JP6441702B2 - Ion source, ion beam apparatus, and sample processing method - Google Patents

Description

  The present invention relates to an ion source, an ion beam apparatus, and a sample processing method.

  Conventionally, an ion beam apparatus provided with an ion source is known as an apparatus for finely processing a sample. The ion beam apparatus can cut the sample by irradiating the sample with the ion beam emitted from the ion source and sputtering the sample surface, and can produce a cross section of the sample.

  In recent years, in order to improve the throughput of sample processing, it is required to increase the beam current of the ion beam. In response to this demand, there is an ion beam apparatus equipped with a plasma ion source capable of obtaining a large beam current of 1 μA or more compared with a conventional liquid metal ion source as an ion source (see, for example, Patent Document 1). In such an ion beam apparatus, a monomer ion beam in which a single gas atom or molecule is ionized is irradiated. However, it is known that the cross-section of a sample prepared by irradiation with a monomer ion beam has an uneven shape due to a difference in etching rate due to local changes in the shape and structure of the sample (curtain effect). ). In addition, the cross section of the sample irradiated with the monomer ion beam may be in a damaged state when argon atoms having high energy enter the sample.

  In recent years, an ion beam apparatus including a cluster ion source that emits cluster ions in which a plurality of gas atoms or molecules are ionized has been developed. For example, Patent Document 2 discloses a gas cluster ion beam irradiation apparatus including a cluster generation mechanism, an ionization mechanism of a cluster generated by the cluster generation mechanism, and an acceleration mechanism of cluster ions ionized by the ionization mechanism. According to the gas cluster ion beam irradiation apparatus described in Patent Document 2, it is possible to perform flattening with low damage that cannot be achieved with a monomer ion beam.

JP 2011-204672 A JP 2006-156065 A

  By the way, the uneven shape of the cross section of the sample formed by irradiation with the monomer ion beam can reduce the uneven shape of the cross section of the sample by processing the sample while changing the incident direction of the monomer ion beam to the sample. . However, when processing by changing the incident direction of the monomer ion beam, it is necessary to irradiate the sample while changing the inclination of the sample as appropriate, and there is a problem that the amount of work increases. Moreover, even if the incident direction of the monomer ion beam is changed, it is difficult to suppress the penetration of argon atoms into the sample.

  In addition, gas cluster ions can flatten the sample surface with low damage, but have a large mass distribution compared to monomer ions, making it difficult to focus on a small beam diameter. A beam current density as large as ions cannot be achieved. For this reason, the ion beam apparatus using the cluster ion beam has a problem that the efficiency of the ion beam apparatus is lower than that in the case of using the monomer ion beam in producing the cross section of the sample.

  Therefore, it is also conceivable to improve the efficiency of sample processing by using monomer ions and cluster ions in combination. However, although monomer ions are also emitted from the conventional cluster ion source, the monomer ion beam emitted from the cluster ion source has a smaller beam current than the monomer ion beam emitted from the plasma ion source. For this reason, it is difficult to improve the efficiency in producing a cross section of a sample by using a conventional cluster ion source in combination as an ion source for monomer ions. Therefore, the conventional ion source and ion beam apparatus have room for improvement in that the sample is efficiently processed by effectively using monomer ions and cluster ions together.

  Therefore, the present invention provides an ion source, an ion beam apparatus, and a sample processing method capable of effectively using monomer ions and cluster ions together.

The ion source according to the present invention includes a source gas introduction unit that introduces a source gas, a cluster generation chamber that is connected to the source gas introduction unit and generates a cluster from the source gas, and the source gas introduction unit. And a plasma generation chamber connected to the cluster generation chamber and having a plasma generation mechanism for generating plasma.
According to the present invention, the ion source can generate monomer ions by converting the source gas into plasma in the plasma generation chamber, and can generate cluster ions by converting the clusters generated in the cluster generation chamber into plasma. For this reason, the ion source can emit a cluster ion beam, and can emit a monomer ion beam of 1 μA or more as well as a conventional plasma ion source. Therefore, an ion source capable of effectively using monomer ions and cluster ions can be provided.

An ion beam apparatus according to the present invention includes the above ion source, and a sample chamber in which a sample irradiated with an ion beam extracted from the plasma generation chamber is disposed.
According to the present invention, since the ion beam apparatus has an ion source capable of generating monomer ions and cluster ions, it is possible to irradiate the sample placed in the sample chamber with the monomer ion beam and the cluster ion beam. As a result, the ion beam apparatus can process the sample in the sample chamber with monomer ions that can be etched at a high rate, and then continuously finish the portion processed with the monomer ions with cluster ions. Therefore, monomer ions and cluster ions can be effectively used together, and the sample can be processed efficiently.

A sample processing method of the present invention is a sample processing method using the ion beam apparatus described above, wherein a step of generating monomer ions from the source gas by the plasma generation mechanism is performed; Irradiating a sample; generating the cluster from the source gas by the cluster generation mechanism; converting the cluster to plasma by the plasma generation mechanism to generate cluster ions; and applying the cluster ions to the sample And irradiating.
According to the present invention, the method includes the step of irradiating the sample with monomer ions and the step of irradiating the sample with cluster ions. Therefore, the processing of the sample by the monomer ion beam and the finishing processing of the sample by the cluster ion beam are performed. Can be done continuously. Therefore, it is possible to provide a sample processing method in which monomer ions and cluster ions can be effectively used together and the sample can be processed efficiently.

  According to the present invention, the ion source can generate monomer ions by converting the source gas into plasma in the plasma generation chamber, and can generate cluster ions by converting the clusters generated in the cluster generation chamber into plasma. For this reason, the ion source can emit a cluster ion beam, and can emit a monomer ion beam of 1 μA or more as well as a conventional plasma ion source. Therefore, an ion source capable of effectively using monomer ions and cluster ions can be provided.

It is a block diagram of a focused ion beam apparatus. It is a flowchart which shows the processing method of a sample. It is a block diagram of the focused ion beam apparatus of a modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, the focused ion beam apparatus 1 will be described as an example of the ion beam apparatus.

(Configuration of focused ion beam device)
First, the configuration of the focused ion beam apparatus 1 will be described.
FIG. 1 is a configuration diagram of a focused ion beam apparatus. In all the following drawings, the dimensions and ratios of the respective components are appropriately changed to make the drawings easy to see.
As shown in FIG. 1, the focused ion beam apparatus 1 includes a sample chamber 10 in which a sample is placed, an ion source 20 that emits an ion beam, an ion beam optical system 50, and a control unit 70.

(Sample chamber)
The sample chamber 10 accommodates a sample stage 11 that moves the sample to the irradiation position of the ion beam irradiated from the ion source 20.
The sample stage 11 can be displaced in five axes. That is, the sample stage 11 includes an X-axis and a Y-axis that are orthogonal to each other in the same plane, and an XYZ-axis mechanism that moves the sample stage 11 along the Z-axis that is orthogonal to the X-axis and the Y-axis, and the X-axis or Y-axis. It is supported by a displacement mechanism that includes a tilt axis mechanism that rotates and tilts the sample stage 11 around the axis, and a rotation mechanism that rotates the sample stage 11 around the Z axis.

  The sample chamber 10 is connected with a first exhaust unit 13 for making the sample chamber 10 in a vacuum state. The first exhaust unit 13 includes a rotary pump 13a and a turbo molecular pump 13b. The turbo molecular pump 13 b is disposed between the rotary pump 13 a and the sample chamber 10. The degree of vacuum of the sample chamber 10 can be adjusted by the first exhaust unit 13.

(Ion source)
The ion source 20 is attached to the sample chamber 10. The ion source 20 includes a cluster generation chamber 30 and a plasma generation chamber 40 formed inside the lens barrel 21, a source gas introduction unit 60, an extraction electrode 26, and a Wien (E × B) filter 27. Yes. The lens barrel 21 is formed in a bottomed cylindrical shape with one end opened. The lens barrel 21 communicates with the sample chamber 10 at an opening at one end.

  The source gas introduction unit 60 introduces argon gas (corresponding to “source gas” in the claims) into the cluster generation chamber 30 and the plasma generation chamber 40 from an argon gas supply source (not shown). The source gas introduction unit 60 includes a switching valve 61, and a first introduction pipe 62 and a second introduction pipe 63 connected to the switching valve 61. The source gas introduction unit 60 can switch the argon gas supplied from the argon gas supply source to the two flow paths of the first introduction pipe 62 and the second introduction pipe 63 in the switching valve 61 to flow therethrough. ing.

  The cluster generation chamber 30 is formed so as to be sandwiched between a bottom portion of the lens barrel 21 and a skimmer 23 disposed inside the lens barrel 21. The skimmer 23 is formed in a conical shape protruding toward the central portion in the cluster generation chamber 30. At the top of the skimmer 23, a hole that communicates the inside and outside of the cluster generation chamber 30 is formed.

  A nozzle 31 is disposed in the cluster generation chamber 30. The nozzle 31 is provided so as to protrude from the bottom of the lens barrel 21 toward the skimmer 23 side. The tip of the nozzle 31 is located in the center of the cluster generation chamber 30 and is formed so as to spread in a conical shape. A first introduction pipe 62 of the source gas introduction unit 60 is connected to the proximal end of the nozzle 31. Thereby, the cluster generation chamber 30 can introduce argon gas. The nozzle 31 functions as a cluster generation mechanism that generates a cluster, which will be described later, together with the source gas introduction unit 60.

  The cluster generation chamber 30 is connected to a second exhaust unit 33 for evacuating the cluster generation chamber 30. The second exhaust unit 33 includes a rotary pump 33a and a turbo molecular pump 33b. The turbo molecular pump 33 b is disposed between the rotary pump 33 a and the cluster generation chamber 30. The cluster generation chamber 30 can adjust the degree of vacuum by the second exhaust unit 33.

  The plasma generation chamber 40 is formed adjacent to the cluster generation chamber 30 on the sample chamber 10 side of the cluster generation chamber 30. The plasma generation chamber 40 is formed so as to be sandwiched between the skimmer 23 and the plasma electrode 25 disposed closer to the sample chamber 10 than the skimmer 23. The plasma electrode 25 gives an acceleration potential to the plasma. The plasma generation chamber 40 communicates with the cluster generation chamber 30 through the hole of the skimmer 23. The plasma generation chamber 40 is connected to the second introduction pipe 63 of the source gas introduction unit 60. Thereby, the plasma generation chamber 40 can introduce argon gas.

  An RF coil 43 is wound around the outer periphery of the plasma generation chamber 40 (the outer periphery of the lens barrel 21). The RF coil 43 is connected to an RF power source 71 provided in the control unit 70. The RF coil 43 functions as a plasma generation mechanism that generates inductively coupled plasma together with the RF power source 71 of the control unit 70.

  The extraction electrode 26 is disposed closer to the sample chamber 10 than the plasma electrode 25. The extraction electrode 26 forms an electric field for extracting an ion beam in the vicinity of the plasma electrode 25. The voltage applied to the plasma electrode 25 and the extraction electrode 26 is controlled by an acceleration-extraction voltage control unit 72 provided in the control unit 70.

  The Wien (E × B) filter 27 is disposed closer to the sample chamber 10 than the extraction electrode 26. The Wien (E × B) filter 27 is a mass filter that passes only ions having a set mass or energy by deflecting incident ions by an electric field and a magnetic field perpendicular to the electric field. The Wien (E × B) filter 27 is connected to a filter control unit 73 provided in the control unit 70, and can appropriately set the mass or energy of ions to be passed.

(Ion beam optics)
The ion beam optical system 50 is disposed closer to the sample chamber 10 than the plasma generation chamber 40. The ion beam optical system 50 irradiates the sample with an ion beam generated in the ion source 20 (details will be described later). The ion beam optical system 50 includes a condenser lens electrode 51 that focuses the ion beam and an objective lens electrode 52 that focuses the ion beam on the sample on the sample stage 11. The condenser lens electrode 51 is disposed between the extraction electrode 26 and the Wien (E × B) filter 27. The objective lens electrode 52 is disposed closer to the sample chamber 10 than the Wien (E × B) filter 27.

(Control part)
The control unit 70 includes the RF power source 71, the acceleration-extraction voltage control unit 72, and the filter control unit 73 described above, and can control the switching valve 61, the first exhaust unit 13, the second exhaust unit 33, the sample stage 11, and the like. It has become.

(Ion beam irradiation principle of focused ion beam device)
Next, the ion beam irradiation principle of the focused ion beam apparatus 1 will be described.
The focused ion beam apparatus 1 of this embodiment can irradiate a monomer ion beam and a cluster ion beam.

First, the principle of irradiation with a monomer ion beam will be described.
When the monomer ion beam is irradiated, argon gas is introduced into the plasma generation chamber 40 through the second introduction pipe 63 of the source gas introduction unit 60. Next, high frequency power is supplied from the RF power supply 71 provided in the control unit 70 to the RF coil 43 to generate a high frequency magnetic field in the plasma generation chamber 40. Thereby, the argon gas in the plasma generation chamber 40 is turned into plasma. At this time, since argon atoms exist in a single state in the plasma generation chamber 40, argon monomer ions are generated.

  Next, monomer ions in the plasma generation chamber 40 are extracted by the extraction electrode 26 through the hole of the plasma electrode 25. Monomer ions extracted from the plasma generation chamber 40 are emitted as a monomer ion beam and focused by the condenser lens electrode 51. The monomer ion beam then passes through a Wien (E × B) filter 27. At this time, since the monomer ion beam is composed of a single ion, the control unit 70 allows the monomer ion beam to pass without controlling the Wien (E × B) filter 27. Next, the monomer ion beam is focused on the sample on the sample stage 11 in the sample chamber 10 by the objective lens electrode 52 and irradiated onto the sample.

Next, the principle of cluster ion beam irradiation will be described.
When irradiating the cluster ion beam, argon gas is introduced into the cluster generation chamber 30 through the first introduction pipe 62 of the source gas introduction unit 60. At this time, the cluster generation chamber 30 is exhausted by the second exhaust unit 33 below a predetermined pressure generated by the cluster. The argon gas ejected from the nozzle 31 is cooled to below the aggregation temperature by adiabatic expansion. A part of the cooled argon gas becomes a cluster in which argon atoms are bonded to each other by van der Waals force and a plurality of argon atoms are clustered. At this time, clusters composed of various numbers of atoms exist in the cluster generation chamber 30. The number of atoms constituting the cluster (hereinafter referred to as “cluster size”) is, for example, about 3000, which is large.

  Argon gas in the cluster generation chamber 30 including the clusters is introduced into the plasma generation chamber 40 through the holes of the skimmer 23. The argon gas in the plasma generation chamber 40 is turned into plasma by the RF coil 43 as in the case of the monomer ion beam irradiation. As a result, argon monomer ions and cluster ions are generated in the plasma generation chamber 40.

  Next, as in the monomer ion beam irradiation, monomer ions and cluster ions in the plasma generation chamber 40 are extracted by the extraction electrode 26 through the holes of the plasma electrode 25. The ion beam emitted from the plasma generation chamber 40 is focused by the condenser lens electrode 51. The ion beam contains both monomer ions and cluster ions when it is emitted from the plasma generation chamber 40. The ion beam then passes through a Wien (E × B) filter 27. At this time, the control unit 70 controls the electric field and magnetic field of the Wien (E × B) filter 27 so that only cluster ions having a predetermined cluster size or larger pass through the Wien (E × B) filter 27. . Thereby, an ion beam turns into a cluster ion beam containing only cluster ions. Next, the cluster ion beam is focused on the sample on the sample stage 11 in the sample chamber 10 by the objective lens electrode 52 and irradiated to the sample.

(Sample processing method using a focused ion beam device)
Next, a sample processing method using the focused ion beam apparatus 1 will be described. In the present embodiment, a method for producing a cross section of a sample observed with a scanning electron microscope, for example, will be described. In addition, please refer FIG. 1 about the code | symbol of each component of the focused ion beam apparatus 1 in the following description.

FIG. 2 is a flowchart showing a sample processing method.
As shown in FIG. 2, the sample processing method of this embodiment includes a monomer ion generation step S <b> 10 for generating monomer ions by generating plasma from argon gas using a plasma generation mechanism (RF coil 43 and RF power supply 71), and monomer ions. Ion irradiation step S20 for irradiating the sample to the sample, cluster generation step S30 for generating a cluster from the argon gas by the cluster generation mechanism (nozzle 31 and raw material gas introduction unit 60), and the cluster is converted into plasma by the plasma generation mechanism to form cluster ions A cluster ion generation step S40 for generating the sample, and a cluster ion irradiation step S50 for irradiating the sample with cluster ions.

First, monomer ion generation step S10 is performed.
In the monomer ion generation step S <b> 10, the control unit 70 first shuts off the supply of argon gas to the first introduction pipe 62 by the switching valve 61 of the raw material gas introduction section 60 and enters the plasma generation chamber 40 through the second introduction pipe 63. Argon gas is introduced. Next, the control unit 70 supplies high-frequency power to the RF coil 43 from the RF power supply 71 provided in the control unit 70 to generate a high-frequency magnetic field in the plasma generation chamber 40, thereby converting argon gas into plasma, and argon monomer ions Is generated.

Next, monomer ion irradiation step S20 is performed.
In the monomer ion irradiation step S20, the sample is processed. In the monomer ion irradiation step S <b> 20, the control unit 70 extracts monomer ions in the plasma generation chamber 40 as a monomer ion beam by the extraction electrode 26. At this time, the acceleration voltage of the monomer ion beam (potential of the plasma electrode 25) is set to 500 V or more, for example. The beam current of the monomer ion beam is set to 1 μA or more, for example. The ion beam extracted by the extraction electrode 26 is irradiated to a predetermined portion of the sample fixed on the sample stage 11 in the sample chamber 10 by the ion beam optical system 50. At this time, since the sample is etched along the irradiation direction of the monomer ion beam, the monomer ion beam is irradiated along the surface direction of the cross section of the sample to be observed. Thereby, a cross section is exposed at a predetermined location on the sample surface. At this point, the cross section of the sample may have an uneven shape due to the curtain effect, and may become amorphous due to high-energy argon atoms entering the sample and be damaged. .

Next, cluster generation step S30 is performed.
In the cluster generation step S <b> 30, the control unit 70 shuts off the supply of argon gas to the second introduction pipe 63 by the switching valve 61 of the source gas introduction unit 60 and enters the cluster generation chamber 30 through the first introduction pipe 62. To introduce. At this time, the argon gas is ejected from the nozzle 31, and a part of the argon gas is aggregated by adiabatic expansion to form a cluster having a cluster size of about 1000 to 3000.

Next, cluster ion generation step S40 is performed.
In the cluster ion generation step S <b> 40, first, argon gas including the cluster generated in the cluster generation step S <b> 30 is introduced into the plasma generation chamber 40 through the hole of the skimmer 23. Next, the control unit 70 supplies high-frequency power to the RF coil 43 from the RF power supply 71 provided in the control unit 70 to generate a high-frequency magnetic field in the plasma generation chamber 40, thereby converting the argon gas containing clusters into plasma. At this time, the argon gas in the plasma generation chamber 40 has both single argon atoms and argon clusters. Therefore, in the plasma generation chamber 40, both argon monomer ions and cluster ions are generated.

Next, cluster ion irradiation step S50 is performed.
In the cluster ion irradiation step S50, as a sample finishing process, the cross section of the sample formed in the monomer ion irradiation step S20 is flattened. In the cluster ion irradiation step S50, the control unit 70 first extracts monomer ions and cluster ions in the plasma generation chamber 40 as an ion beam by the extraction electrode 26. At this time, the acceleration voltage of the ion beam (potential of the plasma electrode 25) is, for example, 500V.

  The ion beam extracted by the extraction electrode 26 is focused on the condenser lens electrode 51 and then passes through the Wien (E × B) filter 27. At this time, the control unit 70 controls the Wien (E × B) filter 27 to pass only cluster ions having a cluster size of, for example, 100 or more. Thereby, the monomer ions and the cluster ions having a small cluster size contained in the ion beam are removed, and the ion beam becomes a cluster ion beam composed only of cluster ions having a cluster size of 100 or more, for example. The cluster ion beam that has passed through the Wien (E × B) filter 27 is focused on the sample on the sample stage 11 in the sample chamber 10 by the objective lens electrode 52, and irradiated to the cross section of the sample formed in the monomer ion irradiation step S20. Is done. Thereby, the cross section of the sample formed by the monomer ion beam can be flattened.

In the cluster ion irradiation step S50, only cluster ions having a large cluster size are irradiated. For this reason, the energy which each argon atom which comprises cluster ion has is sufficiently smaller than the energy which the argon atom of the monomer ion accelerated by the same acceleration voltage has. Thereby, the cluster ion beam can suppress the penetration of argon atoms colliding with the cross section of the sample into the sample. In addition, the cluster ions collapse when colliding with the sample, causing multiple collisions of argon atoms with the sample. As a result, the cluster ion beam has a higher sputtering rate than the monomer ion beam. For this reason, the cluster ion beam can remove the damaged region of the sample cross section formed by irradiation with the monomer ion beam while suppressing new damage to the sample.
This completes the processing of the sample.

As described above, the ion source 20 of the present embodiment includes the source gas introduction unit 60 that introduces argon gas and the source gas introduction unit 60 connected to each other, and a cluster generation mechanism (nozzle 31 and source gas) that generates clusters from the argon gas. A cluster generation chamber 30 including an introduction unit 60), a plasma generation chamber 40 including a plasma generation mechanism (RF coil 43 and RF power supply 71) that connects the source gas introduction unit 60 and the cluster generation chamber 30 and generates plasma; Have
According to this configuration, the ion source 20 can generate monomer ions by converting the argon gas into plasma in the plasma generation chamber 40, and can generate cluster ions by converting the clusters generated in the cluster generation chamber 30 into plasma. For this reason, the ion source 20 can emit a cluster ion beam, and can emit a monomer ion beam of 1 μA or more as well as a conventional plasma ion source. Therefore, an ion source capable of effectively using monomer ions and cluster ions can be provided.

  Moreover, since the focused ion beam apparatus 1 of this embodiment has the ion source 20 which can produce | generate a monomer ion and a cluster ion, it can irradiate a monomer ion beam and a cluster ion beam to the sample arrange | positioned in the sample chamber 10. FIG. As a result, the focused ion beam apparatus 1 can process the sample in the sample chamber 10 with monomer ions that can be etched at a high rate, and then continuously finish the portion processed with the monomer ions with cluster ions. Therefore, monomer ions and cluster ions can be effectively used together, and the sample can be processed efficiently.

  The focused ion beam apparatus 1 has an ion source 20 that can generate monomer ions and cluster ions. Therefore, the apparatus size can be reduced as compared with an apparatus configuration in which a monomer ion beam ion source and a cluster ion beam ion source are separately provided. Therefore, the space for arranging the focused ion beam apparatus 1 can be saved and the apparatus cost can be reduced.

Further, in the sample processing method of the present embodiment, monomer ion generation step S10 for generating monomer ions by generating plasma from argon gas using a plasma generation mechanism (RF coil 43 and RF power source 71), and irradiating the sample with monomer ions. Monomer ion irradiation step S20, cluster generation step S30 for generating a cluster from an argon gas by a cluster generation mechanism (nozzle 31 and source gas introduction unit 60), and cluster ions for generating a cluster ion by converting the cluster into a plasma by a plasma generation mechanism A generation step S40 and a cluster ion irradiation step S50 for irradiating the sample with cluster ions are included.
According to this method, since the method includes the monomer ion irradiation step S20 and the cluster ion irradiation step S50, the sample processing using the monomer ion beam and the sample finishing processing using the cluster ion beam can be continuously performed. it can. Therefore, it is possible to provide a sample processing method in which monomer ions and cluster ions can be effectively used together and the sample can be processed efficiently.

In the focused ion beam apparatus 1 shown in FIG. 1, the plasma is generated by the high frequency magnetic field formed by the RF coil 43 in the plasma generation chamber 40, but the present invention is not limited to this.
FIG. 3 is a configuration diagram of a modified focused ion beam apparatus. As shown in FIG. 3, a magnet 45 such as a neodymium magnet may be disposed around the plasma generation chamber 40 to form a DC magnetic field in the plasma generation chamber 40. Thereby, electrons perform a spiral motion in the plasma generation chamber 40, the probability of collision with the cluster increases, and ionization efficiency can be improved.

The present invention is not limited to the above-described embodiment described with reference to the drawings, and various modifications can be considered within the technical scope thereof.
For example, in the above embodiment, argon is used as the source gas. However, the present invention is not limited to this, and may be neon, krypton, xenon, or the like.

  In the ion source 20 of the above embodiment, the inductively coupled plasma is generated by the RF coil 43 and the RF power source 71 in the plasma generation chamber 40. However, the present invention is not limited to this. For example, capacitively coupled plasma is generated in the plasma generation chamber. It may be configured to.

  Moreover, although the ion source 20 of the said embodiment introduce | transduced argon gas into the plasma production | generation chamber 40 through the 2nd inlet tube 63 at the time of monomer ion production | generation, it is not limited to this. For example, the ion source 20 may be configured to introduce argon gas into the plasma generation chamber 40 through the cluster generation chamber 30 when monomer ions are generated. At this time, the second exhaust unit 33 adjusts the degree of vacuum of the cluster generation chamber 30 to suppress the adiabatic expansion of argon gas, thereby suppressing the generation of argon gas clusters in the cluster generation chamber 30. it can. Thereby, argon atoms in a single state can be introduced into the plasma generation chamber 40.

  Further, the focused ion beam apparatus 1 of the above embodiment is configured to focus the ion beam on the sample by the ion beam optical system 50. However, the present invention is not limited to this, and the focused ion beam apparatus may be configured such that a shield plate is disposed on the sample, and a cross section of the sample is produced by etching a region not shielded by the shield plate.

  Moreover, in the said embodiment, although the focused ion beam apparatus 1 was used for planarization of the cross section of a sample, it is not limited to this. For example, the cluster ion beam can use the focused ion beam apparatus 1 for three-dimensional structural analysis by utilizing a characteristic that a sample can be etched on the order of nanometers. Specifically, the focused ion beam apparatus 1 is provided with a secondary electron detector that detects secondary electrons generated from the sample when the sample is irradiated with the ion beam so that an ion microscope image can be acquired. Then, after finishing the sample in the above-described embodiment, acquisition of a cross-sectional image of the sample and micro-etching of the cross-section of the sample by irradiation with a cluster ion beam are repeatedly performed. Thereby, the slice processing of the sample similar to the conventional focused ion beam apparatus can be performed with low damage, and more accurate three-dimensional structure analysis of the sample becomes possible.

  In addition, it is possible to appropriately replace the components in the above-described embodiments with known components without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Focused ion beam apparatus 10 ... Sample chamber 20 ... Ion source 30 ... Cluster generation chamber 31 ... Nozzle (cluster generation mechanism) 40 ... Plasma generation chamber 43 ... RF coil (plasma generation mechanism) 60 ... Raw material gas introduction part (cluster generation) Mechanism) 71 ... RF power supply (plasma generation mechanism)

Claims (3)

A source gas introduction section for introducing source gas;
A cluster generation chamber having a cluster generation mechanism connected to the source gas introduction unit and generating a cluster from the source gas;
A plasma generation chamber comprising a plasma generation mechanism for connecting the source gas introduction section and the cluster generation chamber and generating plasma;
An ion source comprising: An ion source according to claim 1;
A sample chamber in which a sample irradiated with an ion beam extracted from the plasma generation chamber is disposed;
An ion beam apparatus comprising: A sample processing method using the ion beam apparatus according to claim 2,
Generating plasma from the source gas by the plasma generation mechanism to generate monomer ions;
Irradiating the sample with the monomer ions;
Generating the clusters from the source gas by the cluster generation mechanism;
Converting the cluster into plasma by the plasma generation mechanism to generate cluster ions;
Irradiating the sample with the cluster ions;
A method for processing a sample, comprising:

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