Ion beam generating device, ion beam generating method, analysis method, workpiece manufacturing method, and ionic solution

Abstract

To provide an ion beam generation device capable of generating an ion beam containing various metallic elements or non-metallic elements.SOLUTION: An ion beam generation device includes a solution ion source that stores a solution containing ions, a needle-shaped ejection unit that sprays the solution containing the ions stored in the solution ion source, an electric field applying unit that applies an electric field to the solution containing the ions to electrospray the solution containing the ions from the needle-like ejection unit, and a rotating electric field applying unit disposed on the downstream side of the needle-like ejection unit and applying a rotating electric field to the ions sprayed from the needle-like ejection unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an ion beam generating device, an ion beam generating method, an analysis method, a method for manufacturing a workpiece, and an ionic solution. [Background technology]

[0002] Conventionally, a liquid metal ion source has been used as an ion source for a focused ion beam (FIB) device. This liquid metal ion source has a needle electrode coated with liquid metal. When a voltage is applied between the needle electrode and the extraction electrode, the liquid metal at the tip of the needle electrode takes on a conical shape called a Taylor cone, and metal ions are released from the tip of this cone.

[0003] For example, Patent Document 1 discloses a liquid metal ion source including a reservoir that holds an ionic material that forms a liquid metal, a needle electrode whose surface is covered with the ionic material supplied from the reservoir, an extraction electrode that releases ions of the ionic material from the tip of the needle electrode, a beam aperture that is arranged downstream of the extraction electrode and limits the beam diameter of the ions, and a vacuum chamber that contains these and maintains them in a vacuum. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-51844 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, a liquid metal is used to generate an ion beam. When an ionic material made of a liquid metal is used to emit ions from the tip of a needle electrode, the metal usable for generating the ion beam is limited to gallium, etc. It is desirable to have a technology in which the materials usable for the ion beam generator and ion beam generation method are not limited to a specific metal, and which generates an ion beam using various metallic or non-metallic elements.

[0006] The present disclosure has been made in consideration of the above-described circumstances, and aims to provide an ion beam generating device and ionic solution capable of generating ion beams containing various metal elements or non-metal elements, as well as an ion beam generating method, an analysis method, and a method for manufacturing a workpiece using this device. [Means for solving the problem]

[0007] The means for solving the above problems include the following embodiments. <1> a solution ion source that stores a solution containing ions; a needle-shaped discharge part that sprays the solution containing the ions stored in the solution ion source; an electric field applying unit that applies an electric field to the solution containing ions, thereby spraying the solution containing ions from the needle-shaped discharge unit; a rotating electric field applying unit disposed downstream of the needle-shaped discharge unit and configured to apply a rotating electric field to the ions sprayed from the needle-shaped discharge unit; An ion beam generating device comprising: <2> a beam stopper unit that is disposed between the needle-shaped discharge unit and the rotating electric field application unit and adjusts the solid angle of the ion beam that includes the ions sprayed from the needle-shaped discharge unit; <1> The ion beam generating apparatus according to claim 1. <3> The electric field applying unit includes a first electrode attached to at least a part of the needle-shaped discharge unit, and a second electrode that forms a potential difference between the first electrode and the second electrode. Further equipped <1> or <2> The ion beam generating apparatus according to claim 1. <4> The apparatus further includes a focusing lens disposed between the needle-shaped discharge part and the rotating electric field application part, for focusing the ions sprayed from the needle-shaped discharge part. <1> ~ <3> 1. An ion beam generating apparatus according to claim 1, wherein the ion beam generating apparatus is a <5> a focusing lens disposed between the needle-shaped discharge part and the rotating electric field application part, for focusing the ions sprayed from the needle-shaped discharge part; A part of the focusing lens also serves as the second electrode. <3> The ion beam generating apparatus according to claim 1. <6> The rotating electric field application unit includes two rotating electric field application units arranged in series along the direction in which the solution containing the ions is sprayed from the needle-shaped discharge unit. <1> ~ <5> 1. An ion beam generating apparatus according to claim 1, wherein the ion beam generating apparatus is a <7> a storage chamber that accommodates the needle-shaped discharge unit, the electric field application unit, and the rotating electric field application unit and has an area in which an ion beam is generated; a pressure reducing means for reducing the pressure inside the accommodation chamber by exhaust; Further equipped <1> ~ <6> 1. An ion beam generating apparatus according to claim 1, wherein the ion beam generating apparatus is a <8> <1> ~ <7> 1. An ion beam generating method for generating an ion beam using the ion beam generating apparatus according to any one of claims 1 to 8, the ion-containing solution stored in the solution ion source contains at least two or more types of ions of the same charge, The ion beam generating method generates an ion beam containing specific ions by adjusting the rotating electric field applied to the at least two or more types of ions of the same charge sprayed from the needle-shaped discharge part in the rotating electric field application part and performing mass separation. <9> <1> ~ <7> 2. Using the ion beam generating device according to any one of the preceding claims, or <8> generating an ion beam by the ion beam generation method described in analyzing properties of a workpiece by irradiating the workpiece with the generated ion beam; Analytical methods including: <10> <1> ~ <7> 2. Using the ion beam generating device according to any one of the preceding claims, or <8> generating an ion beam by the ion beam generation method described in a step of manufacturing a workpiece by processing the workpiece by irradiating the generated ion beam onto the workpiece; A method for manufacturing a processed product, comprising: <11> An ionic solution for use in generating an ion beam, comprising at least two or more types of ions of the same charge and a solvent capable of dissolving the at least two or more types of ions of the same charge. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide an ion beam generating device and ionic solution capable of generating ion beams containing various metal elements or non-metal elements, as well as an ion beam generating method, an analysis method, and a method for manufacturing a workpiece using this device. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram illustrating an ion beam generating apparatus according to an example of the present disclosure. [Figure 2] 1 is an enlarged view of a needle-shaped discharge part included in an ion beam generating apparatus according to an example of the present disclosure. [Figure 3] FIG. 1 is a diagram showing metal elements that can be used to generate an ion beam in an ion beam generator using a conventional liquid metal ion source. [Figure 4] FIG. 2 is a diagram showing metal elements and non-metal elements that can be used to generate an ion beam in the ion beam generating device of the present disclosure. [Figure 5] 1 shows the simulation results for ion trajectories. DETAILED DESCRIPTION OF THE INVENTION

[0010] In the present disclosure, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples. In the present disclosure, each component may contain multiple substances corresponding to the component. When multiple substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified. Specific examples of the ion beam generating apparatus and the like of the present disclosure will be described with reference to the drawings, but the present invention is not limited to the configurations shown in the drawings. Also, the sizes of the components in each drawing are conceptual, and the relative size relationships between the components are not limited to these. In the ion beam generating apparatus, the ion beam generating method, the analysis method, the workpiece manufacturing method, and the ionic solution disclosed herein, a preferred aspect of each configuration may be used as a preferred aspect of another configuration. For example, a preferred aspect of the ion beam generating apparatus disclosed herein may be used as a preferred aspect of the ion beam generating method, the analysis method, the workpiece manufacturing method, and the ionic solution disclosed herein.

[0011] [Ion beam generator] The ion beam generating device of the present disclosure includes a solution ion source that stores a solution containing ions, a needle-shaped discharge unit that sprays the solution containing ions stored in the solution ion source, an electric field application unit that applies an electric field to the solution containing ions, thereby electric-field spraying the solution containing ions from the needle-shaped discharge unit, and a rotating electric field application unit that is positioned downstream of the needle-shaped discharge unit and applies a rotating electric field to the ions sprayed from the needle-shaped discharge unit.

[0012] The ion beam generator disclosed herein uses a solution containing ions as an ion source for the ion beam, and is capable of generating ion beams containing various metal elements or nonmetal elements. Furthermore, the ion beam generator includes a rotating electric field application unit, which separates ions contained in the solution according to mass and allows selection of ions to be used for generating the ion beam. Furthermore, when the solution contains multiple types of ions, switching between ion beams is easy.

[0013] On the other hand, ion beam generators using conventional liquid metal ion sources have the following problems, limiting the metals that can be used to generate ion beams. First, liquid metal ion sources require that liquid metal be applied to a needle-shaped electrode in a vacuum, and usable metals are limited to those that can maintain a liquid state in a vacuum and have a low vapor pressure in the liquid state. Furthermore, the liquid metal must have low viscosity and be easy to apply to the needle-shaped electrode. It is also required that a Taylor cone can be formed at the tip of the liquid metal ion source where the liquid metal is ejected.

[0014] In an ion beam generator using a conventional liquid metal ion source, metal elements that satisfy the above conditions and can be used to generate an ion beam are shown in Figure 3. In Figure 3, metal elements (including metalloid elements that can exhibit properties similar to those of metal elements) that can be used to generate an ion beam are shaded. The metal elements and metalloid elements that can be used to generate an ion beam are significantly limited, and expensive metals such as gallium are commonly used.

[0015] On the other hand, in an ion beam generator equipped with a solution ion source, unlike a case where a liquid metal ion source is used, there is no limitation on the elements that can be used to generate an ion beam. Metal elements and non-metal elements that can be used to generate an ion beam in the ion beam generator of the present disclosure are shown in FIG. 4. In FIG. 4, metal elements (including metalloid elements that can exhibit properties similar to those of metal elements) and non-metal elements that can be used to generate an ion beam are indicated by shading. By using the ion beam generator of the present disclosure, it is possible to generate ion beams containing various metal elements or non-metal elements.

[0016] An example of an ion beam generator according to the present disclosure will be described below with reference to Fig. 1. As shown in Fig. 1, the ion beam generator 100 includes a solution ion source 1, a needle-shaped discharge unit 2, a condenser lens 3, an objective lens 4, an orifice 5, a rotating electric field application unit 7, and a storage chamber 8.

[0017] The solution ion source 1 is connected to a storage chamber 8. The needle-shaped discharge part 2, the condenser lens 3, the objective lens 4, the orifice 5, and the rotating electric field application part 7 are housed in the storage chamber 8. Furthermore, the storage chamber 8 has therein a first region 30 and a second region 40, which are regions where an ion beam is generated. The storage chamber 8 is equipped with a turbomolecular pump 31 (pressure reducing means) and an oil rotary pump 32 (pressure reducing means) for reducing the pressure in the first region 30, and a turbomolecular pump 41 (pressure reducing means) and an oil rotary pump 42 (pressure reducing means) for reducing the pressure in the second region 40.

[0018] The solution ion source 1 includes a reservoir for storing a solution to be used for ion beam generation and a flow path for supplying the solution to the needle-shaped discharge part. The solution used for ion beam generation only needs to contain a solvent and at least one type of ion dissolved in the solvent, and the ions contained in the solution are used for ion beam generation.

[0019] The needle-shaped discharge part 2 is configured to receive the solution containing ions from the flow channel of the solution ion source 1 and to discharge the supplied solution from the tip thereof into the first region 30 .

[0020] The ion-containing solution stored in the solution ion source need only contain at least one type of ion having a positive charge or a negative charge, and may also contain two or more types of ions of the same charge (positive charge or negative charge). When two or more types of ions of the same charge are contained, the valences of the ions of the same charge may be the same or different. Even when two or more types of ions of the same charge are contained, mass separation using a rotating electric field application unit 7 (described later) or the like can be performed to generate a first ion beam focused at the center of the optical axis, a second ion beam containing ions of the same charge as the first ion beam and concentrically shaped about the optical axis, etc. Furthermore, by switching the natural frequency corresponding to the mass of an ion to the natural frequency corresponding to the mass of another ion using the rotating electric field application unit 7 (described later), the type of ion beam focused at the center of the optical axis and the type of concentric ion beam centered about the optical axis can be appropriately switched.

[0021] When two or more types of ions of the same charge (positive or negative charge) are contained, the combination thereof is not particularly limited and may be any combination, such as a combination of Cu and Co, or a combination of Li and Na. The two or more types of ions having the same charge (positive charge or negative charge) preferably have the same valence.

[0022] The solution containing ions can be obtained by dissolving molecules or compounds containing the ions in a solvent. The solvent is not particularly limited as long as it can dissolve the ions used to generate the ion beam, and may be selected appropriately depending on the ions used to generate the ion beam.

[0023] Examples of the solvent include water, 2-(2-butoxyethoxy)ethanol (DEGBE), dimethyl sulfoxide (DMSO), toluene, acetone, dichloromethane, etc. From the viewpoint of suppressing condensation after evaporation, the solvent is preferably one that does not easily volatilize from the tip of the needle-shaped discharge part 2. The solvent may be used alone or in combination of two or more.

[0024] The solvent may be a mixed solvent of water and one or more organic solvents. For example, it may be a mixed solvent of water and DEGBE. When a mixed solvent of water and one or more organic solvents is used, the mixing ratio of water to organic solvent is not particularly limited. For example, the ratio of water to organic solvent may be adjusted appropriately to adjust the solution viscosity and surface tension to be suitable for facilitating electrospraying of ions. The mixing ratio (volume ratio) of water to organic solvent may be water:organic solvent = 1:1 to 1:10, or 1:2 to 1:5.

[0025] The concentration of ions in the solution containing ions is not particularly limited. For example, from the viewpoint of facilitating electrospray of ions, the concentration of ions is preferably such that the conductivity of the solution is 100 μS / cm to 50 mS / cm.

[0026] The ion-containing solution used in the ion beam generator 100 may be an ion solution for use in generating an ion beam, which contains at least two or more types of ions and a solvent capable of dissolving the at least two or more types of ions. By using an ion solution containing multiple ions of the same charge and the ion beam generator 100, it is possible to switch ion beams focused on the center of the optical axis, as described below. For example, it is easy to switch an ion beam containing a specific metal element or nonmetal element to an ion beam containing another metal element or nonmetal element.

[0027] An enlarged view of the needle-shaped discharge part 2 is shown in Fig. 2. As shown in Fig. 2, the needle-shaped discharge part 2 includes a flow path 21 through which a solution containing ions flows, a capillary 22 that forms the inner wall of the flow path 21, and an electrode layer 23 (first electrode) provided on the outer wall side of the capillary 22.

[0028] The needle-shaped discharge part 2 has an electrode layer 23, which allows it to function as a needle-shaped electrode. This allows an electric field to be suitably applied to the solution supplied to the needle-shaped discharge part 2. The capillary 22 is preferably made of a non-metallic material, which reduces deformation of the capillary due to stress from an electric field compared to a metallic capillary, allowing the needle-shaped discharge part 2 to emit ions more stably.

[0029] A solution flows through a flow path 21 inside a capillary 22. The electrode layer 23, together with an extraction electrode 6 (second electrode) described later, constitutes an electric field application unit. A voltage is applied to the electrode layer 23, generating a potential difference between the electrode layer 23 and the extraction electrode 6. Application of a voltage to the electrode layer 23 generates an electric field in the direction of arrow E shown in FIG. 2 . When the generated electric field is applied to the solution in the capillary 22, the attractive force of the electric field causes the solution to form a conical Taylor cone 24 at the tip of the needle-shaped discharge unit 2. Ions are released from the Taylor cone 24 into the first region 30, allowing the ions to be electrosprayed. The released ions may be cluster ions of ions contained in the solution and the solvent. The released ions are accelerated by the electric field formed by the electrode layer 23 and the extraction electrode 6 and travel toward the condenser lens 3 and the orifice 5.

[0030] The material of the capillary 22 is not particularly limited, and examples thereof include glass, ceramic, etc. The material of the electrode layer 23 is not particularly limited as long as it is conductive, and examples thereof include gold, platinum, copper, chromium, iridium, tungsten, iron, and alloys thereof.

[0031] The electrode layer 23 may be coated on the entire outer wall of the capillary 22, or may be coated on only a portion of the outer wall of the capillary 22. When the electrode layer 23 is coated on only a portion of the outer wall of the capillary 22, it is preferable that the electrode layer 23 be coated near the tip of the needle-shaped discharge part 2.

[0032] The hole diameter at the tip of the needle-shaped discharge part 2 is not particularly limited as long as it is possible to electrospray a solution containing ions, and may be, for example, 5 μm to 50 μm.

[0033] The ion beam generator 100 may include a heating means for heating the solution supplied to the needle-shaped discharge unit 2 in order to adjust the viscosity of the ion-containing solution, or may not include the heating means in order to simplify the device configuration. In the present disclosure, a solution is used to generate the ion beam, and therefore, unlike when a liquid metal is used, a heating means is not essential.

[0034] The condenser lens 3 and objective lens 4 are focusing lenses for focusing the ions sprayed from the needle-shaped discharge part, and are arranged in this order between the needle-shaped discharge part 2 and the rotating electric field application part 7. Focusing by a focusing lens is a concept that includes increasing the density of ions and focusing the beam to a point.

[0035] The extraction electrode 6 is a part of the condenser lens 3, and constitutes an electric field application unit together with the electrode layer 23. A part of a focusing lens such as a condenser lens may also serve as the extraction electrode (second electrode). For example, as shown in FIG. 1, the condenser lens 3 closest to the needle-shaped discharge part 2 may also serve as the extraction electrode 6.

[0036] The shortest distance between the tip of the needle-shaped discharge part 2 and the extraction electrode 6 is preferably 0.1 mm to 5 mm, more preferably 0.3 mm to 3 mm, and even more preferably 0.5 mm to 2.0 mm. When the shortest distance is 0.1 mm or more, discharge between the needle-shaped discharge part 2 and the extraction electrode 6 tends to be suppressed. When the shortest distance is 5 mm or less, an electric field tends to be applied locally to the tip of the needle-shaped discharge part 2.

[0037] The potential difference generated between the electrode layer 23 and the extraction electrode 6 is preferably 1 kV to 5 kV, and more preferably 2 kV to 3 kV. In this case, when the ions used to generate the ion beam are cations (e.g., metal ions), the electrode layer 23 preferably has a higher potential than the extraction electrode 6. When the ions used to generate the ion beam are anions (e.g., non-metal ions), the extraction electrode 6 preferably has a higher potential than the electrode layer 23. Furthermore, when a liquid metal is used to generate the ion beam, a higher potential difference (e.g., 7 kV or more) is required. On the other hand, when a solution is used to generate the ion beam, a lower potential difference can be achieved, which prevents excessive electric field concentration at the tip of the needle-shaped discharge part 2 and increases the ion emission angle.

[0038] The electric field strength generated between the electrode layer 23 and the extraction electrode 6 is 2×10 5 V / m~2×10 6 V / m is preferred, and 5×10 5 V / m~1×10 6 V / m is more preferable.

[0039] The condenser lens 3 is a lens that densifies the ions emitted from the needle-shaped discharge part 2 into a beam. The condenser lens 3 is preferably an electrostatic lens that densifies the ions using an electric field. The condenser lens may be an Einzel-type lens consisting of three sets of lenses, with the entrance and exit lenses at the same potential and the central lens at a higher or lower potential than the entrance and exit lenses. However, in the present disclosure, a lens configuration other than an Einzel-type lens may also be used as the condenser lens. For example, an immersion-type lens consisting of three sets of lenses, with the entrance and exit lenses at different potentials, is preferred.

[0040] The orifice 5 is a beam restrictor that adjusts the solid angle of the ion beam IB containing the ions sprayed from the needle-shaped discharge part 2 . The orifice 5 is located between the extraction electrode 6 and the condenser lens 3 (for example, an intermediate condenser lens) other than the extraction electrode 6. This makes it possible to increase the acceptance angle of the beam. An aperture for adjusting the ion beam diameter may be disposed between the condenser lens 3 and the objective lens 4, more specifically, between the condenser lens 3 on the exit side and the objective lens 4 on the entrance side.

[0041] Furthermore, the first region 30 and the second region 40 in the accommodation chamber 8 are connected via the opening of the orifice 5. The first region 30 and the second region 40 are separated by the orifice 5, and the degree of vacuum in the first region 30 upstream of the orifice 5 is adjusted by a turbomolecular pump 31 and an oil rotary pump 32 (hereinafter also referred to as a "pre-operational exhaust system"), and the degree of vacuum in the second region 40 downstream of the orifice 5 is adjusted by a turbomolecular pump 41 and an oil rotary pump 42 (hereinafter also referred to as a "post-operational exhaust system"). The degrees of vacuum in the first region 30 and the second region 40 can be adjusted separately via the orifice.

[0042] The diameter of the opening of the orifice is not particularly limited, and may be, for example, 0.5 mm to 2 mm, or 0.8 mm to 1.5 mm.

[0043] The needle-shaped discharge part 2 and the extraction electrode 6 are arranged in the first region 30. The condenser lens 3 (intermediate lens and outer lens), the objective lens 4, and the rotating electric field application part 7, other than the extraction electrode 6, are arranged in the second region 40.

[0044] In the first region 30, the degree of vacuum near the tip of the needle-shaped discharge part 2 is reduced to a maximum of 1×10 5 Pa~3×10 5 The pressure may rise to about 100 Pa. Furthermore, a large number of neutral particles are generated due to gasification during electrospraying. Therefore, in order to prevent the degree of vacuum from increasing, it is preferable to reduce the pressure in the first region 30 using a pre-operation exhaust system, and to ensure that the second region 40 is in an exhausted state using the orifice 5.

[0045] On the other hand, in the second region 40, the degree of vacuum is 5×10 by the orifice 5 and the post-actuated exhaust system. -6 Pa~5×10 -3 It is preferable that the pressure is adjusted to 1×10 Pa. -5 Pa~1×10 -4 It is more preferable that the temperature is adjusted to Pa.

[0046] The objective lens 4 is disposed between the condenser lens 3 and the rotating electric field application unit 7. The objective lens 4 is a lens that focuses the ion beam IB to a point. The objective lens 4 is preferably an electrostatic lens that focuses ions to a point by an electric field. The objective lens 4 may be an Einzel-type lens consisting of three pairs of lenses, in which the entrance-side lens and the exit-side lens are at the same potential, and the central lens is at a higher or lower potential than the entrance-side and exit-side lenses.

[0047] In the traveling direction of the ion beam IB, an alignment electrode, a deflection electrode, etc. (not shown) for adjusting the irradiation direction of the ion beam IB may be arranged between the condenser lens 3 and the objective lens 4.

[0048] The rotating electric field applicator 7 is disposed downstream of the needle-shaped discharger 2 and applies a rotating electric field to the ions sprayed from the needle-shaped discharger 2. The rotating electric field applicator 7 is disposed downstream of the objective lens 4 and applies a rotating electric field to the ion beam IB focused by the objective lens 4. The ion beam IB focused by the objective lens 4 enters the entrance of the rotating electric field applicator 7 along the traveling direction of the ion beam IB and is emitted from the exit of the rotating electric field applicator 7. It is preferable that the center of the entrance of the rotating electric field applicator 7 approximately coincides with the center of the optical axis.

[0049] The rotating electric field applying part 7 includes two rotating electric field applying units arranged in series along the direction in which the ion-containing solution is sprayed from the needle-shaped discharge part 2 (the same as the traveling direction of the ion beam IB).

[0050] The two rotating electric field application units constituting the rotating electric field application section 7 are each a multipole type electric field application means. Examples of multipole electrode configurations include a quadrupole, an octupole, and a decapole. The multipole type electric field application means may be a cylindrical electric field application means obtained by dividing a cylinder into equal parts, such as an octupole electric field application means obtained by dividing a cylinder into eight parts as shown in FIG. 1. The multipole type electric field application means is not limited to a shape obtained by dividing a cylinder into equal parts, and may also be an electric field application means having multiple rectangular electrode plates arranged at equal intervals about the optical axis.

[0051] From the viewpoint of suppressing distortion of the electric field in the effective ion optical path (Φ≦10 mm), the multipole electrode configuration is preferably an octapole or a decapole, and the multipole electric field applying means is preferably a cylinder with equal divisions.

[0052] The two rotating electric field application units constituting the rotating electric field application unit 7 are each connected to a radio-frequency sine wave generator, and the sine wave signal generated by the radio-frequency sine wave generator is input to each electrode constituting the rotating electric field application unit. The sine wave signal generated by the radio-frequency sine wave generator may be amplified by an amplifier and then input to each electrode constituting the rotating electric field application unit. Phase-shifted sine wave signals are applied to each electrode to rotate the electric field within the rotating electric field application unit. The subsequent rotating electric field application unit preferably applies a rotating electric field in the same direction but in the opposite phase to that of the previous rotating electric field application unit. This causes the previous rotating electric field application unit to deviate from the center of the optical axis, and the subsequent rotating electric field unit to return the ion beam IB (especially ions having a mass-to-charge ratio corresponding to the ion's natural frequency) that has deviated from the center of the optical axis to the center of the optical axis.

[0053] The rotating electric field applicator 7 performs mass separation while maintaining the focusing characteristics of the ion beam IB. In the rotating electric field applicator 7, the rotating electric field frequency of the sinusoidal signal is the frequency (eigenfrequency: f) specific to the mass of the ions contained in the ion beam IB, and ions with mass-to-charge ratios (m / Z) corresponding to the given frequency form a concentric pattern around the center of the optical axis. At this time, the downstream rotating electric field unit selects and focuses ions returning to the center of the optical axis, spatially separating ions of different mass numbers in a concentric pattern. This allows for selective separation of an ion beam containing ions of a specific mass number. Furthermore, because the focusing characteristics of ions relative to the optical axis follow the potential distribution of the rotating electric field applicator 7, no additional optical axis correction (mechanical axis adjustment, electrical alignment correction, astigmatism correction) is required.

[0054] By allowing multiple ions of the same charge to coexist in an ion-containing solution, multiple ions can be emitted from the needle-shaped discharge unit 2. In this case, by inputting a frequency specific to the mass of a specific ion as the rotating electric field frequency, an ion beam can be formed while separating the masses. For example, by inputting a frequency specific to the mass of a specific ion into the rotating electric field application unit 7, it is possible to obtain a first ion beam that focuses on the center of the optical axis, and a second ion beam that contains ions of the same charge as the first ion beam and is concentric with the optical axis.

[0055] The first ion beam focused on the center of the optical axis and the second ion beam concentrically focused around the optical axis may be ion beams (cluster ion beams) consisting of clusters of ions and solvent contained in a solution. The clusters of ions and solvent may include multiple types of clusters with different molar ratios of solvent to ions. When multiple types of clusters are supplied to the rotating electric field application unit 7, a cluster ion beam having a specific size can be selectively obtained by mass separation.

[0056] When multiple ions of the same charge coexist in a solution containing ions, the ion beam focused on the center of the optical axis can be switched by switching the frequency specific to the mass of a specific ion to the frequency specific to the mass of another ion. For example, it is easy to switch an ion beam containing a specific metal element or nonmetal element to an ion beam containing a different metal element or nonmetal element.

[0057] The natural frequency can be switched by operating an external PC (personal computer). The switching speed of the natural frequency is determined by the time constant of the high-frequency sine wave generator and amplifier. Selection of elements to be included in the ion beam is possible only by electric field modulation through natural frequency switching, and there is no need to physically switch the ion beam source in a vacuum. The response time required for natural frequency switching is less than one-tenth of the period of the natural frequency. Therefore, selection of elements to be included in the ion beam is very close to a continuous process.

[0058] The voltage value of the electrode layer 23 in the needle-shaped discharge part 2 affects the initial kinetic energy of the ions, which determines the AC voltage value of the sinusoidal signal applied to the multipole constituting the rotating electric field application part 7. In addition, the focusing electric field applied to the condenser lens 3 and the objective lens 4 changes depending on the initial kinetic energy.

[0059] The ion beam generator 100 may include an aperture plate with apertures downstream of the rotating electric field application unit 7. Ion beams can be selected by passing a specific ion beam through the apertures. The position of the aperture plate is not particularly limited as long as the center of the optical axis passes through the apertures in the aperture plate, and multiple ion beams may be passed through by adjusting the size of the apertures.

[0060] The ion beam generated by the ion beam generator of the present disclosure may be used to analyze the properties of a workpiece to be irradiated, or may be used for ion implantation into the workpiece, film formation by vapor deposition, surface removal processing, etc. When using the ion beam, the elements contained in the ion beam may be selected or switched as needed to analyze or process the workpiece.

[0061] [Ion beam generation method] The ion beam generation method disclosed herein generates an ion beam using the ion beam generator disclosed herein. The ion-containing solution stored in the solution ion source contains at least two or more types of ions of the same charge. The rotating electric field applied to the at least two or more types of ions of the same charge sprayed from the needle-shaped discharge unit is adjusted by the rotating electric field applicator to perform mass separation, thereby generating an ion beam containing specific ions. In the ion beam generation method disclosed herein, by allowing multiple ions of the same charge to coexist in the ion-containing solution, multiple ions can be emitted from the needle-shaped discharge unit 2. In this case, by inputting a frequency specific to the mass of the specific ion as the rotating electric field frequency to the rotating electric field applicator, an ion beam can be formed while performing mass separation. Furthermore, by allowing multiple ions of the same charge to coexist in the ion-containing solution, a first ion beam focused at the center of the optical axis and a second ion beam containing ions of the same charge as the first ion beam and concentrically oriented around the optical axis can be obtained.

[0062] [Analysis method] The properties of a workpiece may be analyzed using the ion beam generated by the ion beam generating device of the present disclosure. For example, an analysis method of the present disclosure includes a step of generating an ion beam using the ion beam generating device of the present disclosure or by the ion beam generating method of the present disclosure, and a step of analyzing the properties of the workpiece by irradiating the workpiece with the generated ion beam.

[0063] In the analysis method disclosed herein, an ion beam can be generated as described above, and the generated ion beam is irradiated onto a workpiece. The properties of the workpiece can be analyzed based on the behavior and state of the workpiece resulting from the ion beam irradiation. For example, secondary ion mass spectrometry (SIMS) may be performed, in which an ion beam is irradiated onto the surface of a solid placed in a vacuum, and ions generated by collisions between the beam ions and the solid surface at the molecular or atomic level are detected by a mass spectrometer.

[0064] [Manufacturing method for processed products] The method for manufacturing a workpiece of the present disclosure includes a step of generating an ion beam using the ion beam generating device of the present disclosure or by the ion beam generating method of the present disclosure, and a step of manufacturing the workpiece by processing the workpiece by irradiating the workpiece with the generated ion beam.

[0065] In the method for manufacturing a workpiece according to the present disclosure, an ion beam can be generated as described above, and the generated ion beam is irradiated onto a workpiece, thereby enabling processing such as ion implantation, film formation by vapor deposition, and surface removal processing of the workpiece, thereby manufacturing the workpiece.

[0066] In the method for manufacturing a workpiece disclosed herein, a plurality of ions of the same charge are allowed to coexist in an ion-containing solution, and a rotating electric field application unit is used to switch the characteristic frequency of a specific ion relative to its mass to the characteristic frequency of another ion relative to its mass, thereby enabling switching of the ion beam focused on the center of the optical axis. This allows processing such as ion implantation, film formation by vapor deposition, and surface removal of the workpiece while switching from an ion beam containing a specific metal element or nonmetal element to an ion beam containing another metal element or nonmetal element.

[0067] <Simulation of the trajectories of different ions in a rotating electric field> When the rotating electric field rotation frequency (f = 353 kHz) is applied to the rotating electric field application section, a hypothetical cluster ion, [Co(CH 14 O3)] +is focused at the center of the optical axis, [Cu(CH 14 O3)] + , [Li(CH 14 O3)] + and [Pb(CH 14 O3)] + The behavior of each cluster ion consisting of CH was simulated. The rotating electric field application section assumed in the simulation consisted of two rotating electric field application units, and the dimensions of the octopole constituting each unit were an outer diameter of 25 mm and an inner diameter of 20 mm, and the length of each unit in the optical axis direction was 150 mm. 14 O3 refers to 2-(2-butoxyethoxy)ethanol, Co represents elemental cobalt, Cu represents elemental copper, Li represents elemental lithium, and Pb represents elemental lead. The positive charge of the cluster ion was set to monovalent, which is stable in vacuum.

[0068] The simulation results for the ion trajectory are shown in Figure 5. As shown in Figure 5, [Co(CH 14 O3)] + is focused at the center of the optical axis, [Cu(CH 14 O3)] + ([Co(CH 14 O3)] + The ions with masses close to those of [Li(CH)] formed a circular pattern around the optical axis. 14 O3)] + ([Co(CH 14 O3)] + The ions, which have a slightly smaller mass than [Pb(CH), collide with the inner wall of the multipole that constitutes the rotating electric field application section, and the reflected ions follow a trochoidal orbit. 14 O3)] + ([Co(CH 14 O3)] + The results of this simulation show that the first ion beam (in Figure 5, [Co(CH 14 O3)] + ions of the same charge as the first ion beam (in Figure 5, [Cu(CH14 O3)] + ) was predicted to be obtained. [Explanation of symbols]

[0069] 1. Solution ion source 2 Needle-shaped discharge part 3 Condenser Lens 4 Objective Lenses 5 Orifice 6 Extraction electrode 7 Rotating electric field application unit 7 8 Containment Cell 21 Flow path 22 Capillary 23 Electrode layer 24 Taylor Cone 100 Ion beam generator

Claims

1. a solution ion source that stores a solution containing ions; a needle-shaped discharge part that sprays the solution containing the ions stored in the solution ion source; an electric field applying unit that applies an electric field to the solution containing ions, thereby spraying the solution containing ions from the needle-shaped discharge unit; a rotating electric field applying unit disposed downstream of the needle-shaped discharge unit and configured to apply a rotating electric field to the ions sprayed from the needle-shaped discharge unit; Equipped with the rotating electric field application unit includes two rotating electric field application units arranged in series along a direction in which the ion-containing solution is sprayed from the needle-shaped discharge unit, An ion beam generating apparatus that applies phase-shifted sinusoidal signals to the electrodes that make up the rotating electric field application unit, thereby rotating the electric field within the rotating electric field application unit.

2. 2. The ion beam generating device according to claim 1, further comprising a beam limiter arranged between the needle-shaped discharge unit and the rotating electric field application unit, the beam limiter adjusting a solid angle of the ion beam containing the ions sprayed from the needle-shaped discharge unit.

3. The electric field applying unit includes a first electrode attached to at least a part of the needle-shaped discharge unit, and a second electrode that forms a potential difference between the first electrode and the second electrode. The ion beam generating device according to claim 1 or 2, further comprising:

4. 4. The ion beam generating device according to claim 1, further comprising a focusing lens disposed between the needle-shaped discharge part and the rotating electric field application part, for focusing the ions sprayed from the needle-shaped discharge part.

5. a focusing lens disposed between the needle-shaped discharge part and the rotating electric field application part, for focusing the ions sprayed from the needle-shaped discharge part; The ion beam generating device according to claim 3 , wherein a part of the focusing lens also serves as the second electrode.

6. a storage chamber that accommodates the needle-shaped discharge unit, the electric field application unit, and the rotating electric field application unit and has an area in which an ion beam is generated; a pressure reducing means for reducing the pressure inside the accommodation chamber by exhaust; The ion beam generating device according to any one of claims 1 to 5, further comprising:

7. An ion beam generating method for generating an ion beam using the ion beam generating apparatus according to any one of claims 1 to 6, the ion-containing solution stored in the solution ion source contains at least two or more types of ions of the same charge, The ion beam generating method includes: adjusting a rotating electric field applied to the at least two or more types of ions of the same charge sprayed from the needle-shaped discharge part in the rotating electric field application part, thereby performing mass separation, thereby generating an ion beam containing specific ions.

8. generating an ion beam by using the ion beam generating device according to any one of claims 1 to 6 or by the ion beam generating method according to claim 7; analyzing properties of a workpiece by irradiating the workpiece with the generated ion beam; Analytical methods including:

9. generating an ion beam by using the ion beam generating device according to any one of claims 1 to 6 or by the ion beam generating method according to claim 7; a step of manufacturing a workpiece by processing the workpiece by irradiating the generated ion beam onto the workpiece; A method for manufacturing a processed product, comprising:

10. At least two or more types of ions of the same charge and a solvent capable of dissolving the at least two or more types of ions of the same charge, The ionic solution for use in generating an ion beam, wherein the at least two or more kinds of ions of the same charge contain a combination of Cu and Co or a combination of Li and Na.

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