Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J27/00—Ion beam tubes
  • H01J27/02—Ion sources; Ion guns
  • H01J27/20—Ion sources; Ion guns using particle beam bombardment, e.g. ionisers
  • H01J27/205—Ion sources; Ion guns using particle beam bombardment, e.g. ionisers with electrons, e.g. electron impact ionisation, electron attachment
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/02—Details
  • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/02—Details
  • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
  • H01J37/08—Ion sources; Ion guns
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
  • H01J37/305—Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating, or etching
  • H01J37/3053—Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating, or etching for evaporating or etching
  • H01J37/3056—Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating, or etching for evaporating or etching for microworking, e. g. etching of gratings or trimming of electrical components
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
  • H01J2237/05—Arrangements for energy or mass analysis
  • H01J2237/057—Energy or mass filtering
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
  • H01J2237/06—Sources
  • H01J2237/061—Construction
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
  • H01J2237/06—Sources
  • H01J2237/08—Ion sources
  • H01J2237/0815—Methods of ionisation
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
  • H01J2237/16—Vessels
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
  • H01J2237/30—Electron or ion beam tubes for processing objects
  • H01J2237/317—Processing objects on a microscale
  • H01J2237/31701—Ion implantation
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
  • H01J2237/30—Electron or ion beam tubes for processing objects
  • H01J2237/317—Processing objects on a microscale
  • H01J2237/31735—Direct-write microstructures

Definitions

• the present invention relates to a multiply charged ion source and a charged particle beam apparatus using the multiply charged ion source.
• Removing an electron from an atom can produce a positive ion, but for example, X e 4 4 + ions that have removed two or more electrons are called positive multivalent ions.
• Multivalent ions have extremely large internal energy, and when a multivalent ion collides with a solid surface, a large number of secondary electrons are emitted, or a nanometer size around the incident point of multivalent ions. Many unique phenomena are known to occur, including structural changes (see references 1 and 2 below). This unique interaction between multiply-charged ions and substances has the potential to be applied to nanometer-scale process technologies such as single-ion implantation plantation and quantum dot fabrication (see Reference 3 below).
• Electron cyclotron resonance (ECR) ion source (ECRIS) and electron beam ion source (EBIS) are generally known as ion sources that generate such multiply charged ions. The latter is characterized by a high ionization degree of the resulting ion.
• ECR electron cyclotron resonance
• EBIS electron beam ion source
• a fusion research laboratory device developed for atomic physics research is known (for example, see Reference 4 below). This device is composed of an electron source, a drift tube, a collector, a solenoid magnet, an ion extraction lens, and the like.
• the electron emitted from the force electrode is a drift tube placed in a magnetic field. Passed through and collected by the collector.
• Electrons are compressed by a strong magnetic field formed in the drift tube, resulting in a high current density electron beam.
• the gas introduced from the vicinity of the cathode is ionized in the drift chew.
• the drift tube electrode is divided into several parts, and a potential is applied so that a well-type potential having barriers against ions at both ends is formed. Ion is for a certain time, It is confined in this well-type potential, and the impact ionization by electrons proceeds to become multivalent ions.
• multiply charged ions the one whose kinetic energy increases due to electron collision and exceeds the barrier is guided to the ion extraction lens side (the multiply charged ions are taken out to the ion source section).
• the EBIT (electron beam ion trap) of the conventional example 2 improved from the EBIS of the conventional example 1 was developed (see reference 5 below).
• the EBIT generation principle of EBIT is the same as that of EBIS, but the superconducting Helmholt coil is used and the drift tube is made shorter than before to avoid plasma instability in the drift tube. In this way, the ion confinement time is improved, so that a high number of multiply charged ions can be held stably. For this reason, E B I T has made it possible to generate a high ionization ion by focusing the electron beam in the drift tube to the ultimate.
• the equipment at the Puruk Haven Laboratory in the United States consists of a superconducting magnet, an electron source necessary for ion generation, a drift tube, and a collector (here, these are collectively referred to as an ion source electrode) They are separated (see reference 9 below).
• an ion source electrode the equipment at the Puruk Haven Laboratory in the United States consists of a superconducting magnet, an electron source necessary for ion generation, a drift tube, and a collector (here, these are collectively referred to as an ion source electrode) They are separated (see reference 9 below).
• the heat resistance of the superconducting magnet part is weak in the EB IS of Conventional Example 6, so that a sufficient degree of vacuum cannot be obtained unless evacuation is continued for a very long time.
• the central axes of the electron source, drift tube, and collector need to be adjusted with high precision.
• the axis of the ion source electrode alone can be aligned. Therefore, a lot of time was required for assembly and adjustment
• a superconducting magnet is required for ion generation, as in the multivalent ion source in Conventional Example 6.
• separation from the ion source electrode it was necessary to break the vacuum of the ion source electrode. For this reason, when the superconducting magnet is not assembled, the ion source electrode alone cannot be aligned, and a great deal of time is required for assembly and adjustment.
• the present invention provides a multi-ion source that is easy to manufacture, has excellent operability and maintainability, has a high power consumption, and has a large beam, and a charged particle beam apparatus using the same. It is aimed.
• the present inventors have manufactured, assembled, and adjusted by disposing the ion source electrode in the same vacuum container and the superconducting magnet in different vacuum containers. It has been found that a highly-charged ion source that is easy to operate and has excellent operability. In addition, the acceleration voltage is reduced to 4 O k V or less, and the ion source electrode shape and superconducting coil optimal for this are used to increase the intensity and size of the multi-ion beam. The invention has been completed.
• the multivalent ion generation source of the present invention includes an ion source electrode including an electron source, a drift tube serving as an ion confinement region, and a collector, and a superconducting magnet for ion confinement.
• the ion introduction means, and the multivalent ion generation source further comprises a first vacuum container containing the ion source electrode and a second vacuum container containing the superconducting magnet.
• the first vacuum vessel and the second vacuum vessel are each provided with an evacuation device.
• the second vacuum vessel is formed in an annular shape in cross section, and the first vacuum vessel is disposed through the ring of the first vacuum vessel.
• the second vacuum vessel is preferably removable from the first vacuum vessel without breaking both vacuums.
• Super The conducting magnet is preferably a superconducting magnet using a Helmholtz type coil. It is preferable to set the acceleration voltage of the electron source to 10 to 40 kV.
• the superconducting magnet is accommodated—with the second vacuum vessel detached from the first vacuum vessel, the first vacuum vessel and the contained ion source electrode are sufficiently heated. And can be degassed.
• the first vacuum vessel for generating multivalent ions can be brought to an extremely high vacuum in a short time. Therefore, in the multivalent ion generation source of the present invention, the ion source electrode can be started up in a short time, so that a multivalent ion generation source with excellent operability and maintainability can be realized.
• the charged particle beam apparatus of the present invention is characterized by using the above-mentioned multivalent ion generation source and irradiating the sample surface with multivalent ions.
• Another configuration of the charged particle beam device includes an ion source including a drift tube and a collector serving as an electron source and a ion confinement region, an electrode, a superconducting magnet for ion confinement, and ion introduction. Means, a first vacuum vessel containing an ion source electrode, a second vacuum vessel containing the superconducting magnet, and a vacuum exhaust disposed in each of the first vacuum vessel and the second vacuum vessel.
• a third vacuum vessel connected to the multivalent ion generation source, and a vacuum exhaust device thereof, and further comprising:
• the ion separator and the sample stage are arranged on the sample stage, and the sample is placed on the sample stage, so that a desired multivalent ion is selected from the multivalent ions generated by the multivalent ion source by the ion separator. Irradiate the sample surface And it is characterized in and.
• the charged particle beam device preferably further includes a sample observation device and / or a sample surface treatment device.
• various multivalent ions generated from the multivalent ion generation source are irradiated with the sample by selecting a desired multivalent ion by the ion separator.
• the surface cleaning device can clean the sample surface before the multi-ion irradiation.
• the multivalent ion generation source since the multivalent ion generation source is small and light, it can be applied to a nano process.
• FIG. 1 is a cross-sectional view schematically showing the configuration of a multiply-charged ion source according to the present invention.
• FIG. 2 is an enlarged cross-sectional view schematically showing the configuration of the electron source shown in FIG.
• FIG. 3 is a cross-sectional view schematically showing the configuration of a polyvalent ion source having a solid ion source as the ion source.
• FIG. 4 is a schematic block diagram for explaining a power source applied to the multivalent ion generation source of the present invention.
• FIG. 5 is a diagram schematically showing a configuration of a charged particle beam apparatus using the multiply-charged ion generation source of the present invention.
• FIG. 6 is a diagram showing a magnetic field generated by a superconducting magnet having a Helmholtz-type coil used in the multivalent ion generation source of the example.
• Figure 7 shows the calculation results of the electron beam trajectory when electrons are accelerated at 40 keV in the multiply-charged ion source of the example.
• (A) is near the force sword
• (b) is It is a figure which shows the collector vicinity.
• FIG. 1 is a cross-sectional view schematically showing the configuration of a multiply-charged ion source according to the present invention.
• a multivalent ion generation source 1 of the present invention includes an ion source electrode 3 disposed in a first vacuum vessel 2 and a superconducting ion confinement disposed in a second vacuum vessel 10.
• a conductive magnet 11 and a gas ion introducing means 20 are provided.
• the ion source electrode 3 includes an electron source 4, a drift tube 5 serving as an ion confinement region, and a collector 6.
• the first and second vacuum devices 2 and 10 have independent configurations, but the first vacuum device 2 is disposed so as to pass through the inside of the second vacuum device 10. That is, in this embodiment, the first vacuum vessel 10 is formed in a cylindrical shape with an annular cross section and open at both ends. Thus, the first vacuum device 1 is arranged through the ring of the cylindrical first vacuum vessel 10. A superconducting magnet 11 is annularly arranged inside a cylindrical second vacuum vessel 10.
• the first vacuum vessel 2 and the second vacuum vessel 10 are evacuated independently by the vacuum evacuation devices 15 and 16, respectively.
• the first vacuum container 2 for Okai on occurrence, 1 X 1 0- 5 P a ( Pascal) or less, and especially 1 X 1 0- 3 P a hereinafter the extreme high vacuum.
• the first vacuum vessel 2 is provided with baking means using a baking heater (not shown) for degassing. By using this baking means, the first vacuum vessel 2 can be baked to about 2500-300.
• the first and second vacuum vessels 2 and 10 are formed of a material such that at least their opposing surfaces are applied with the magnetic field from the superconducting magnet 11 to the drift tube 5.
• the nonmagnetic material austenitic stainless steel (for example, SUS-304, SUS-3116) or aluminum can be used.
• a superconducting magnet 11 is accommodated in the second vacuum vessel 10 so as to be thermally cut off from the outside.
• the superconducting magnet 11 is kept at a cryogenic temperature of, for example, 10 K ( ⁇ 26 3 ° C.). It is designed to be cooled.
• the true ⁇ the second vacuum chamber 1 0 is a high vacuum of about 1 0- 4 P a. Baking means for obtaining such a high vacuum is not necessary.
• a magnetic shield 18 is provided on the outer periphery of the first vacuum vessel 10 on the first vacuum vessel 2 side. The magnetic shield 18 is disposed so that the magnetic field from the superconducting magnet 11 does not leak to the electron source 4 of the ion source electrode 3 and the drift tube 5 on the collector 6 side.
• the magnetic shield 18 may be made of a ferromagnetic material such as soft iron.
• FIG. 2 is an enlarged cross-sectional view schematically showing the configuration of the electron source 4 shown in FIG.
• the electron source 4 is connected to the ultrahigh vacuum flange 2 a on the left side surface of the first vacuum vessel 2 via the support portion 2 b on the horizontal central axis of the first vacuum vessel 2. It is arranged.
• the diameter of the void of the superconducting magnet 11 accommodated in the second vacuum vessel 10 is indicated by D. is doing.
• the arrow in the figure indicates the exhaust path.
• the electron source 4 is arranged from left to right in the order of a filament (force sword) electrode 4 a, a focus electrode 4 b, an anode electrode 4 c, and a snout electrode 4 d, each of which is a terminator 4 e, 4 e
• the thread is 3 ⁇ 4 ⁇ .
• the electron source 4 includes a backing coil 7 for setting the magnetic field in the vicinity of the force sword to 0 (zero), and is accommodated in the magnetic shield unit 8.
• the above-mentioned force sword electrode 4a, anode electrode c, and snow electrode 4d and the insulators 4e, 4e are assembled by fitting together to increase the mutual axis. Match with accuracy.
• the anode potential is 4 k + + 10 kV for the anode electrode 4 c and + 15 k for the snout electrode 4 d, based on the filament potential. V potential is applied.
• the electron source 4 can be accommodated in the ultra-high vacuum flange 2 a having an outer diameter of 16 2 mm and an inner diameter of 10 2 mm, and the electron source 4 side of the second vacuum vessel 10 The diameter can be reduced to 1 52 mm.
• the inner diameter of the ultra-high vacuum flange 2a is sufficiently larger than the diameters of the magnetic shield part 8 and the drift tube 5, the emitted gas from the electron source 4 region can be exhausted efficiently.
• the annular gap of the second vacuum vessel 10 that accommodates the superconducting magnet 11, that is, the bore diameter of the superconducting magnet can be reduced.
• the device of the multiply-charged ion source 1 can be downsized. By being able to reduce the size, the manufacturing cost and operating cost of the device can be reduced.
• the drift tube 5 is composed of a cylindrical electrode divided into several parts, and both ends thereof have an electric field arrangement that forms a barrier (well-type potential) against ions.
• the gas that becomes ions is introduced into the interior of the drift tube 5 from the side by the gas ion introduction means 20.
• the stage 20 includes a gas source 20 a, a flow rate adjusting unit 2 O b, a piping unit 20 c into the first vacuum vessel 2, and the like.
• FIG. 3 is a cross-sectional view schematically showing the configuration of a multivalent ion source having a solid ion source.
• the multivalent ion generation source shown in FIG. 3 is different from the multivalent ion generation source shown in FIG. 1 in that a solid ion introduction means 22 is provided on the right side of the collector 6 instead of the gas ion introduction means 20. It is that you are.
• a vacuum arc ion source or the like can be used in which needle-shaped solid material for generating desired ions is subjected to vacuum arc discharge and ionized (monovalent). Ions generated from the solid ion introduction means 2 2 pass through the collector 6 in the first vacuum vessel 2 and are injected into the drift tube 5.
• the ions injected into the drift tube 5 by the ion introduction means consisting of the above gas ion introduction means 20 or solid ion introduction means 22 are confined in a well-type potential for a certain period of time, and the impact ionization by electrons proceeds. It becomes a multivalent ion.
• these polyvalent ions the one that increases kinetic energy due to electron collision and exceeds the barrier is taken out of the multivalent ion source 1.
• the multiplying ion beam jumps out by changing the electric field arrangement. Is generated.
• the collector 6 is an electrode for collecting electrons passing through the drift tube 5 and is composed of electrodes such as a suppressor electrode, a collector electrode, and an extractor one electrode, for example.
• the force sword and the collector 6 are applied with a voltage of about several tens of kV to about 300 kV with respect to the ground.
• the acceleration voltage may be a voltage for obtaining a desired multivalent ion.
• the electrons are applied with the maximum acceleration voltage immediately before entering the drift tube 5, and the electrons passing through the drift tube 5 are decelerated to about 2 to 3 kV before the collector 6 and collected by the collector 6. Therefore, the collector 6 collects the power of the product of this voltage and the electron beam current.
• This power is 9 0 0 W when the voltage before the collector 6 is 3 kV and the electron beam current is 30 O mA, and when it hits the collector 6 in a narrowed state, The place melts. Accordingly, the collector 6 collects electrons while expanding the electron beam as an electrode structure cooled with a refrigerant.
• the superconducting magnet 11 uses a so-called Helmholtz type coil composed of a first coil 1 la and a second coil 11 b.
• the radius of the first coil 1 1 a and the second coil 1 1 b is a, and the distance between these coils is the same as the radius a, the magnetic field in the central part of the opposing coil is made uniform. be able to.
• the superconducting magnet 11 is cooled by a closed cycle refrigerator using He (not shown) as a refrigerant, and is maintained in a superconducting state.
• a feature of the multivalent ion generation source 1 of the present invention is that a superconducting magnet 11 for ion confinement is disposed in a second vacuum vessel 10, and an annular gap in the second vacuum vessel 10 is provided. That is, the first vacuum vessel 2 is inserted. That is, the first vacuum vessel 2 is inserted in the gap of the superconducting magnet 11.
• the ion source 3 including the electron source 4, the drift tube 5, and the collector 6 is disposed in the first vacuum vessel 2.
• the first vacuum vessel 10 that accommodates the superconducting magnet 11 can be detached without breaking the vacuum of the first vacuum vessel 2 and the like.
• the multivalent ion generation source of the present invention is configured as described above. Next, the operation thereof will be described.
• FIG. 4 is a schematic block diagram for explaining a power source applied to the multiply-charged ion source 1 of the present invention.
• An example of an electron acceleration voltage of 40 kV is shown.
• the filament of electron source 4 is 15 V, 2 A
• the focus electrode is 50 V, 1 mA
• the anode electrode is 10 kV
• the snow electrode is 15 kV.
• 1 mA power is added to the 130 kV power supply.
• each electrode of the drift tube 5 has a first electrode 5 0 0 V and a second electrode 5 0 0 V on a 10 kV power source.
• the third electrodes 50 OV are supplied by being added to each other.
• the suppressor electrode, collector electrode, and extractor electrode of collector 6 are added with 2 kV, 3 kV, 50 OmA, and 13 reductions, respectively, to the -3 OkV power supply. Have been supplied.
• Electrons generated from the electron source 4 pass through a drift tube 5 disposed in the magnetic field of the superconducting magnet 11.
• a drift tube 5 disposed in the magnetic field of the superconducting magnet 11.
• Electrons that have entered the drift tube 5 after being accelerated are compressed by the strong magnetic field formed in the drift tube 5 by the superconducting magnet 11, and have an electron beam with a large current density (: ⁇ 100 OA / cm 2 ).
• collector 6 collects the gas after decelerating to about 2-3 kV. The electrons are applied with the maximum acceleration voltage immediately before the drift tube 5.
• the gas to be ions introduced from the gas ion introduction means 20 is ionized in the drift tube 5.
• the electrode of the drift tube 5 is divided into several parts, and a potential is applied to both ends so that a barrier (well-type potential) is formed against ions. Ions are confined in this well-type potential for a certain period of time, and gas atoms are ionized by repeatedly colliding with an electron beam. Impact ionization by electrons proceeds and becomes multivalent ions. Among these multiply charged ions, the kinetic energy increases due to electron collision and exceeds the barrier, and is taken out of the ion source.
• the intensity of the resulting multiply charged ion beam 24 is proportional to the length L 1 of the drift tube 5 in which ions are trapped (see Fig. 1) and the emission current, and the time until the ionization degree reaches the ultimate is Proportional to current density. If the drift tube 5 is too long, plasma instability will appear and high ionization polyion will not be possible.
• the electron beam current density increases as the magnetic field strength applied to the drift tube 5 by the superconducting magnet 11 increases (however, it is not proportional). For this reason, the intensity of the multiply-charged ion beam 24 obtained per unit time can be increased as the electron beam current density is higher and the trap region is longer.
• the above multivalent ion generation mechanism is the same as the conventional multivalent ion generation source.
• a feature of the present invention is that a vacuum exhaust device 15 for the first vacuum vessel 2 that houses the ion source electrode 3 and a vacuum exhaust for the first vacuum vessel 10 that contains the superconducting magnet 11 1.
• the device 16 can be detached and detached. For this reason, the first vacuum vessel 2 and the ion source electrode 3 accommodated in the second vacuum vessel 10 containing the superconducting magnet 11 are sufficiently separated from the first vacuum vessel 2. Can be degassed by heating.
• the first vacuum vessel 2 for generating multiply charged ions can be made an extremely high vacuum in a short time.
• the ion source electrode 3 can be started up in a short time, so that the highly-charged ion source 1 having excellent operability and maintainability is realized. be able to.
• FIG. 5 is a diagram schematically showing a configuration of a charged particle beam device 30 using the multiply-charged ion source 1 of the present invention.
• the third vacuum vessel 31 is connected to the multivalent ion generation source 1, and the third vacuum vessel 31 is included in the third vacuum vessel 31.
• the third vacuum vessel 3 1 is evacuated by the evacuation device 3 5 independently of the evacuation devices 15 and 16 of the multivalent ion generation source 1.
• the ion separator 32 is provided for selecting a desired multivalent ion from various multivalent ions generated from the multivalent ion source 1.
• an analysis magnet deflection magnet
• a Wien filter using a magnetic field and an electric field, or the like can be used as the ion separator 3 2.
• the sample stage 34 can use an XYZ stage or the like so that its position can be controlled.
• the charged particle beam device 30 may include a sample surface observation device 36.
• an observation apparatus include an electron beam diffraction apparatus, a scanning electron microscope (S E M), a scanning tunneling microscope (S TM), and a secondary ion mass spectrometer (S I M S).
• a sample surface treatment apparatus 37 may be provided. Examples of such a surface treatment apparatus include a surface cleaning apparatus and a vapor deposition apparatus.
• the various multivalent ions generated from the multivalent ion source 1 are irradiated with the sample by selecting the desired multivalent ions in the ion separator 3 2.
• the surface of the sample can be cleaned by the surface cleaning device 37 before irradiation with the multiply charged ions.
• the observation device 36 can be used to observe the shape of the sample and its crystal state during irradiation with multiply charged ions. According to the charged particle beam apparatus 30 using the multiply-charged ion source 1 of the present invention, since the multi-charged ion source 1 is small and light, it can be applied to a nano process.
• an acceleration voltage of 10 to 40 kV, an electron beam current of 30 O mA, an ion confinement magnetic field of 3 T, and a commercially available superconducting magnet as a superconducting coil is separated from an electron beam and ion beam.
• the polyvalent ion source 1 disposed in the second vacuum vessel 10 was manufactured (see FIGS. 1 and 2).
• a Helmholtz coil type was adopted as the superconducting coil, and the ion confinement region was widened by using a drift tube 5 having a length of 200 mm.
• FIG. 6 is a diagram showing a magnetic field generated by a superconducting magnet T1 having a Helmholtz-type coil used in the multiply-charged ion source 1 of the example.
• the horizontal axis indicates the distance (mm) in the horizontal axis from the cathode to the collector 6, and the vertical axis indicates the magnetic field (Tesla (T)) formed in the first vacuum vessel 2.
• the maximum magnetic field is 3 T
• the uniform magnetic field range of 5% from the maximum magnetic field is 10 Omm. For this reason, if the length of the drift tube 5 ′ was 100 to 20 Omm, a substantially uniform magnetic field could be formed at the center.
• Figure 7 shows the calculation results of the electron beam trajectory when electrons are accelerated at 40 keV in the multiply-charged ion source 1 of the example.
• (A) is near the force sword
• (b) is the collector It is a figure which shows the vicinity.
• the horizontal axis (a) is from the force sword
• (b) is from the left end of the collector
• the vertical axis is from the horizontal axis (X) to the vertical direction (Y
• the distance (mm) to) is shown.
• the calculation of the electron beam trajectory was performed using the TriComp 2 D (Fiedel Frecione on) software.
• Beam direction Horizontal Vertical Table 1 compares the EBIT of the multivalent ion source 1 of the example and the conventional example 3.
• the maximum accelerating voltage of the multiply-charged ion source 1 in the example is 40 kV necessary for ionizing xenon, the maximum electron beam current is 30 mA, and cooling of the superconducting magnet right 1 1 is a closed cycle.
• the magnetic field strength is 3 T, and the beam of multiply charged ions can be emitted horizontally.
• the maximum acceleration voltage is 30 kV to ionize uranium
• the maximum electron beam current is 30 O mA
• the superconducting magnet is cooled by a liquid He tank.
• the magnetic field strength is 4.5 T, and the beam of multiply charged ions can be emitted in the vertical direction.
• the major difference between the multivalent ion source 1 of the present invention and the EBIT of the conventional example 3 is its size (height X width L 2). In the present invention, 0.6 mx 1 m, respectively, Then it is 3 m X 2 m. As described above, the multivalent ion source 1 of the present invention can be made smaller in size than the EBIT of Conventional Example 3.
• the multivalent ion generation source of Conventional Example 3 was a large apparatus of 3 mx 2 m (vertical type), but in the embodiment, a compact apparatus of 0.6 mx lm (horizontal type)
• a highly-charged ion source 1 having equivalent or better performance can be realized from the viewpoint of application to nanoprocesses.
• the superconducting magnet 11 was accommodated in a second vacuum vessel 10 different from the first vacuum vessel 2 in which an electron beam and an ion beam were accommodated, thereby facilitating device fabrication.
• a second vacuum vessel 10 different from the first vacuum vessel 2 in which an electron beam and an ion beam were accommodated, thereby facilitating device fabrication.
• a nanoprocess using multivalent ions can be performed.
• the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and it goes without saying that these are also included in the scope of the present invention.
• the ion source electrode configuration including the drift tube and collector serving as the electron source and the ion confinement region and the magnetic field strength of the superconducting magnet are appropriately changed according to the acceleration voltage and the electron beam current it can.
• the first vacuum vessel for generating multiply-charged ions can be brought to an extremely high vacuum in a short time, so that the ion source electrode can be started up in a short time. Therefore, a highly-charged ion source with excellent operability and maintainability can be realized.
• this device is small and light and can be manufactured at low cost.
• the multivalent ion generation source since the multivalent ion generation source is used, in addition to providing a small and lightweight charged particle beam apparatus, it is possible to start up the vacuum in a short time. Excellent operability and maintainability. Therefore, it can be suitably used for nanoprocesses.

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