JP3405161B2 - Ion beam irradiation equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, an ion implantation apparatus, an ion doping apparatus (non-mass separation type ion implantation apparatus), a thin film forming apparatus using both ion irradiation and vacuum deposition, which is extracted from an ion source. The present invention relates to an ion beam irradiation apparatus for irradiating an object to be irradiated with an ion beam in a processing chamber, and more specifically to a means for analyzing the composition of the ion beam extracted from the ion source.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a conventional ion beam irradiation apparatus. This ion beam irradiation apparatus is used for the ion source 2
In the treatment chamber 12, the irradiation target 16 (for example, a semiconductor substrate, a liquid crystal display substrate, etc.) 16 is irradiated with the ion beam 10 extracted from the irradiation target, and a treatment such as ion implantation is performed on the irradiation target 16. Is configured to apply. The inside of the processing chamber 12 is evacuated to a vacuum (for example, about 10 ⁻⁵ to 10 ⁻⁶ Torr) by the vacuum exhaust device 14.

The ion source 2 is the introduced ion source gas 2
A plasma generation unit 4 for generating plasma 6 by ionizing 6 by, for example, high-frequency discharge, microwave discharge, arc discharge, etc., and an ion beam by the action of an electric field from the plasma 6 provided near the exit of the plasma generation unit 4. It has an extraction electrode system 8 for drawing out 10.

The lead-out electrode system 8 has four porous electrodes in this example, and the first electrode and the plasma generator 4 (more specifically, the plasma generator constituting the electrode) counted from the upstream side thereof. The container 5) has a positive high voltage (for example, 10 kV-) for extracting and accelerating the ion beam 10.
About 100 kV) is applied from the DC power supply 20. DC voltages are applied to the second and third electrodes from the DC power supplies 21 and 22, respectively, as shown in the figure. The fourth electrode and the processing chamber 12 are grounded. The energy of the ion beam 10 in this case is about 10 keV-100.
It becomes about keV.

Although there is an idea that the ion source gas 26 is introduced into the processing chamber 12 and supplied to the plasma generating unit 4 through the extraction electrode system 8, in this example, the ion source gas 26 is supplied to the plasma generating unit 4. Are introduced directly. This is because it is preferable in that the gas pressure of the ion source gas 26 in the plasma generation unit 4 can be increased to generate the dense plasma 6.

In this case, since the high voltage is applied to the plasma generating unit 4 as described above, the high voltage pedestal of the same potential as the plasma generating unit 4 is conventionally supported by the insulator from the ground potential portion. A gas source (for example, a gas cylinder) 24 is installed in (not shown), and the ion source gas 26 is supplied at the same potential. That is, the gas source 24 for supplying the ion source gas 26 and the plasma generator 4 are connected to the metal pipe 2
7, the pressure reducing valve 28 and the flow rate regulator 3
0 are provided, and all of them are provided on the high voltage pedestal.

The ion source gas 26 is, for example, PH ₃ (phosphine), B ₂ H ₆ (diborane), or B ₂ H ₆ (diborane) in the case of manufacturing semiconductor devices (specifically, for implanting impurities into semiconductors).
A gas such as AsH ₃ (arsine) or a gas obtained by diluting them with hydrogen or the like.

This ion beam irradiation apparatus is provided with an ion source 2
The ion beam 10 extracted from the irradiation target 16 is directly irradiated to the irradiation target 16 without mass separation.
The ion beam 1 extracted from the ion source 2 is used to measure a desired ion implantation amount (dose amount) into the ion source 2.
It is necessary to know (analyze) the composition of 0. Therefore, conventionally, a mass spectrometer 18 is provided so as to communicate with a portion of the processing chamber 12 facing the ion source 2, and a part of the ion beam 10 extracted from the ion source 2 is incident on the mass spectrometer 18. The mass analysis of the ion beam 10 is performed by 18. The mass spectrometer 18 includes a mass separator 18a that mass-separates the ion beam 10 using a magnetic field or an orthogonal electromagnetic field, and an ion detector 18b that receives ions derived therefrom. An ion implanter including such a mass spectrometer 18 is disclosed in, for example, Japanese Patent Laid-Open No. 6-36737.

[0009]

In the above ion beam irradiation apparatus, since the ion beam 10 extracted from the ion source 2 is subjected to mass analysis by the mass analyzer 18, as the energy of the ion beam 10 increases,
The mass spectrometer 18 (more specifically, the mass separator 18a constituting the mass spectrometer) is upsized. For example, the mass separator 18
If a uses magnetic field deflection, the ion beam 10
As the energy of 1 increases, the magnetic field strength necessary for deflecting the ions in the ion beam 10 increases remarkably, and the coil forming the mass separator 18a increases significantly in size. The same applies to the case where the mass separator 18a uses an orthogonal electromagnetic field. By the way, the energy of the ion beam 10 extracted from the ion source 2 is
For example, as described above, it is about 10 keV to 100 keV, which is extremely large.

Further, the degree of vacuum in the processing chamber 12 is not good (that is, the gas pressure is high) because the ion source 2 is large (large area) and the ion source gas 26 that diffuses into the processing chamber 12 is large. ) State, the ions in the ion beam 10 are neutralized by collision with gas molecules in the atmosphere or the molecular ions are decomposed until they are emitted from the ion source 2 and analyzed by the mass spectrometer 18. As a result, the composition of the ion beam 10 analyzed by the mass spectrometer 18 changes to a different composition from the original one, and accurate analysis cannot be performed.

Therefore, it is a main object of the present invention to provide an ion beam irradiation apparatus capable of accurately analyzing the composition of an ion beam extracted from an ion source by using a small mass spectrometer.

[0012]

A first ion beam irradiation apparatus according to the present invention is a part of ions which are attached to a plasma generating section of the ion source and which form plasma generated in the plasma generating section. Mass spectrometer for injecting the ions through a small hole to perform mass analysis of the ions, a vacuum exhaust device provided in a ground potential part for evacuating the inside of the mass analyzer, the vacuum exhaust device and the mass analyzer And an insulating pipe provided in the middle of the exhaust pipe for connecting with (1).

According to the above structure, the mass spectrometer attached to the plasma generation part of the ion source can take in a part of the ions constituting the plasma generated in the plasma generation part and perform mass analysis thereof. In addition, since the mass spectrometer is provided with a vacuum exhaust device for vacuum exhaust, it is possible to prevent the taken ions from colliding with residual gas molecules to cause neutralization and decomposition. Therefore, the mass spectrometry of the ion can be accurately performed.

The ions thus taken into the mass spectrometer for mass analysis and the ion beam extracted from the extraction electrode system of the ion source are both extracted from the same plasma and are basically the same as each other. Have a composition. Therefore, by accurately performing the mass analysis of the ions by the mass spectrometer, the composition of the ion beam extracted from the ion source can be accurately measured, though indirectly, without being affected by the deterioration of the degree of vacuum in the processing chamber. Can be analyzed.

Moreover, the ions that enter the mass spectrometer from the plasma generation unit have only the acceleration energy due to the electric field in the ion sheath in the plasma peripheral region and the kinetic energy associated with the diffusion of the plasma. The energy is much smaller than that of the ion beam extracted from the electrode system, so that the mass spectrometer can be downsized.

Further, the electric insulation between the vacuum exhaust device provided in the ground potential part and the mass spectrometer to which a high voltage is applied by being attached to the plasma generation part can be performed by the above-mentioned insulating tube, and the vacuum can be obtained. Since the exhaust device is installed in the ground potential part, it is easy to supply power to the vacuum exhaust device and is less susceptible to the high voltage surge generated in the high voltage part such as the extraction electrode system. It is possible to prevent a failure or malfunction of the vacuum exhaust device due to.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an example of an ion beam irradiation apparatus according to the present invention. FIG. 2 is an enlarged sectional view showing a detailed example of the mass spectrometer in FIG. The same or corresponding portions as those of the conventional example shown in FIG. 5 are designated by the same reference numerals, and the differences from the conventional example will be mainly described below.

In this embodiment, the mass spectrometer 18 is not attached to the processing chamber 12 as in the conventional example, but
A mass spectrometer 70 is attached to the plasma generation unit 4 of the ion source 2. The mass spectrometer 70 includes a part 7 of ions constituting the plasma 6 generated by the plasma generation unit 4.
Is injected through the small hole 76 to perform mass analysis of the ion 7.

More specifically, as shown in FIG. 2, a hole 68 is provided in the side wall portion of the plasma generating portion 4 (more specifically, the plasma generating container 5 constituting the plasma generating portion 4) so as to communicate with the hole 68. The mass spectrometer 70 is attached to the plasma generation unit 4. The mass spectrometer 70 includes a vacuum container 72,
A mask 74 provided at the entrance, a mass separator 78 provided at the back, an ion detector 80 provided at the back, and an ammeter 82 connected thereto are provided.

The mask 74 serves to limit the incident ions and to make a pressure difference between the inside of the plasma generation unit 4 and the inside of the mass spectrometer 70. A part 7 of the ions constituting the plasma 6 is made incident. It has a small hole 76 to allow it. The size of the small hole 76 is, for example, about 1 mm to 3 mm in diameter.

The mass separator 78 uses at least one of a magnetic field and an electric field to perform mass separation of the ions 7 incident through the small holes 76 (depending on the difference in the ratio m / q between the mass m of the ions and the charge q). It is to select). The mass separator 78 shown in FIG. 2 is a quadrupole mass separator having a quadrupole electrode, but in addition, an analysis magnet for deflecting the ions 7 by a magnetic field to perform mass separation, a quadrature electromagnetic field ( E × B separator for mass separation of ions 7 by E × B) (also called Wien filter)
And so on.

The ion detector 80 receives the ions extracted from the mass separator 78 and measures them as a current, and is composed of a Faraday cup in this example. An ammeter 82 is connected to the ion detector 80, that is, between the ion detector 80 and the plasma generation container 5, whereby the ion current flowing through the ion detector 80 can be measured. .

This ion beam irradiation apparatus is further provided with a vacuum exhaust device 92 provided in the ground potential part and for exhausting the inside of the mass spectrometer 70 to vacuum. The vacuum exhaust device 92 and the mass spectrometer 70 are connected by a metal exhaust pipe 88, and an insulating pipe 90 is provided in the middle thereof. As shown in FIG. 2, one end of the exhaust pipe 88 is connected to a side wall of the vacuum container 72 and an exhaust port 84 provided near the mass separator 78. Reference numerals 86 and 87 in FIG. 2 are packings made of O-rings for sealing.

The plasma generating unit 4 is evacuated by the vacuum evacuation device 14 described above through the extraction electrode system 8, and the ion source gas 26 described above for generating the plasma 6 is introduced into the plasma generating unit 4 to generate an ion source. During the operation of No. 2, for example, it is maintained at about 10 ⁻³ to 10 ⁻⁴ Torr. On the other hand, the plasma generation unit 4 and the mass spectrometer 70 are connected to each other through a small hole 76, and the inside of the mass spectrometer 70 is evacuated to about 10 ^-5 to 10 ^-6 Torr by a vacuum exhaust device 92. It That is, the plasma generation unit 4 and the mass spectrometer 70 are differentially exhausted.

Since the mass spectrometer 70 is attached to the plasma generation unit 4, the high voltage described above is applied from the DC power source 20 to have a high potential, like the plasma generation unit 4. On the other hand, the vacuum exhaust device 92 is installed in the ground potential section as described above. Therefore, in this embodiment, the insulating pipe 90 is provided in the middle of the exhaust pipe 88 as described above, and with this insulating pipe 90, the potential difference between the mass spectrometer 70 and the vacuum exhaust device 92, that is, the mass spectrometer. It insulates the high voltage applied to 70. The insulating tube 90 is made of ceramics such as alumina or resin such as fluororesin. At the connecting portion between the insulating pipe 90 and the exhaust pipe 88, packing composed of an O-ring for sealing is provided.
The illustration is omitted.

In this ion beam irradiation apparatus, some of the ions 7 forming the plasma 6 generated in the plasma generation unit 4 of the ion source 2 are made incident on the mass spectrometer 70 through the small holes 76, and this mass analysis is performed. The device 70 allows mass spectrometry of the ions 7. An ion sheath is formed between the peripheral portion of the plasma 6 and the plasma generation container 5, and the plasma 6 is generated by the electric field in the ion sheath.
The ions inside are accelerated toward the wall surface of the plasma generation container 5, and a part 7 thereof enters the mass spectrometer 70 through the small hole 76. Also, due to the diffusion motion of the plasma 6, some of the ions forming the plasma 6 enter the mass spectrometer 70 through the small holes 76. In this way, the energy of the ions 7 incident on the mass spectrometer 70 is, for example, 1 eV to 10 eV.
It is about 0 eV.

Moreover, since this ion beam irradiation apparatus is provided with the vacuum exhaust device 92 for evacuating the inside of the mass spectrometer 70, the degree of vacuum in the mass spectrometer 70 is increased (that is, the gas pressure is lowered). ), It is possible to prevent the incident ions 7 from colliding with residual gas molecules to cause neutralization and decomposition in the mass spectrometer 70. Therefore, the mass analysis of the ion can be accurately performed.

The ions 7 thus taken into the mass spectrometer 70 for mass analysis and the ion beam 10 extracted from the extraction electrode system 8 of the ion source 2 are both extracted from the same plasma 6. , Basically have the same composition as each other. Therefore, by accurately performing the mass analysis of the ions 7 by the mass spectrometer 70, the composition of the ion beam 10 extracted from the ion source 2 is indirectly, but the degree of vacuum in the processing chamber 12 is deteriorated. It can be analyzed accurately without being affected.

Moreover, the energy of the ions 7 incident on the mass spectrometer 70 from the plasma generator 4 is, for example, about 1 eV to 100 eV as described above, and the energy of the ion beam 10 extracted from the extraction electrode system 8 (this is the above-mentioned). As described above, it is much smaller than, for example, about 10 keV to 100 keV). Therefore, the mass separator 78 for mass-separating the ions 7 need only be small, and the mass spectrometer 70 can be miniaturized.

Further, since the vacuum evacuation device 92 for evacuating the inside of the mass spectrometer 70 is provided in the ground potential part, as compared with the case where it is provided in the high voltage part having the same potential as the plasma generation part 4, There is such an effect. That is, if the vacuum exhaust device 92 is provided in the high voltage part having the same potential as the plasma generation part 4, an insulating transformer is required to supply power to the vacuum exhaust device 92 from the ground potential part. Also,
The vacuum evacuation device 92 is easily affected by a high voltage surge generated in a high voltage part such as the extraction electrode system 8 and easily causes a failure or malfunction. Further, since the vacuum exhaust device 92 is mounted on the above-mentioned high-voltage pedestal, the high-voltage pedestal becomes large, and the insulating space surrounding the high-voltage pedestal also becomes large, and the ion beam irradiation device becomes large. On the other hand, as in this embodiment, by providing the vacuum evacuation device 92 in the ground potential part and electrically insulating the mass evacuation device 92 and the mass analysis device 70 by the insulating tube 90, the insulation transformer is not required. Therefore, it becomes easy to supply power to the vacuum exhaust device 92, and the vacuum exhaust device 92 is less susceptible to the high voltage surge generated in the high voltage section. Can be prevented. Further, since no space for the vacuum exhaust device 92 is required on the high-voltage pedestal, this ion beam irradiation device can be downsized.

The ion beam 10 is used as described above.
The analysis of the composition is particularly effective in an apparatus which directly irradiates the irradiation target 16 without mass-separating the ion beam 10 extracted from the ion source 2 as in this embodiment, but other than such an apparatus. In this case, for example, the ion beam 10 extracted from the ion source 2 is also used.
In a device that irradiates the irradiation target 16 after roughly separating the mass (that is, separating only the ion species having a large mass difference),
Since it is important to know the composition of the ion beam 10 extracted from the ion source 2, the effect can be exhibited.

By the way, the gas source 24 for introducing the ion source gas 26 into the plasma generating section 4 is considerably large in size in order to prevent the throughput of the ion beam irradiation apparatus from being lowered by reducing the frequency of replacement. When the amount of the ion source gas 26 supplied to the plasma generation unit 4 is increased to extract a large amount of the ion beam 10, the size becomes even larger.

Therefore, when the gas source 24 is installed on the high-voltage pedestal as described above, the high-voltage pedestal becomes large,
As a result, the insulating space surrounding the high-voltage pedestal also becomes large, and the device becomes large.

Further, the high-voltage pedestal provided on the insulator is
It is located at a relatively high position from the floor surface (ground potential portion), and it is not safe to replace the large gas source 24 at such a high position.

Unlike the above example, the gas source 2 is connected to the ground potential portion.
4 is installed, an insulating pipe is provided in the middle of the metal pipe 27, and the insulating pipe is used to insulate the high voltage applied to the plasma generation unit 4. Although it is preferable to install the gas source 24 in the ground potential portion in this way in terms of downsizing of the device and safety in handling the gas source 24,
It is not safe from the viewpoint of leakage of the ion source gas 26 from the insulating pipe portion that the high voltage is simply insulated by the insulating pipe. This is because, for example, in the case of manufacturing a semiconductor device, a gas containing toxicity (for example, PH ₃ , B ₂ H ₆ , AsH _{3 and the} like described above) may be used as the ion source gas 26. This is because the insulating pipe is generally weaker in mechanical strength than the metal pipe, and gas leakage easily occurs. For example, the material of the insulating pipe is usually resin such as fluororesin or ceramics such as alumina. In the case of resin, since it is easily deformed, gas leakage easily occurs depending on the tightening condition. Further, when a high voltage is applied to cause creeping discharge, carbonization may occur and gas leakage may occur, and a hole may be formed depending on the case. For ceramics,
Since it is brittle, it is apt to crack or break due to external force, which may cause gas leakage.

By the way, although a part of the ion source gas 26 introduced into the plasma generating section 4 slightly flows into the insulating tube 90 through the mass spectrometer 70,
Since the insulating pipe 90 and its connecting portion are evacuated to a negative pressure by the vacuum exhaust device 92, the insulating pipe 90 and its insulating pipe 90 are provided unlike the case of the insulating pipe provided in the middle of the metal pipe 27 that becomes positive pressure. There is no risk that the ion source gas 26 will leak out from the connection portion.

Then, next, in addition to the above-mentioned problems concerning the analysis of the composition of the ion beam 10, the ion source gas 2
FIG. 3 shows an embodiment in which the problem concerning the introduction of No. 6 is also solved.

This ion beam irradiation apparatus is provided with a double insulating tube 40 having an inner insulating tube 42 and an outer insulating tube 44 surrounding the outer side of the inner insulating tube 42 with a space therebetween. Both the insulating tubes 42 and 44 are made of, for example, ceramics such as alumina, and have a high voltage applied to both ends thereof, that is, the high voltage applied from the DC power source 20 to the plasma generation unit 4 of the ion source 2. Has withstand voltage.

In this example, metal flanges 46 and 48 are provided at both ends of the inner insulating pipe 42 and the outer insulating pipe 44, respectively, as shown in FIG. 4, and both metal flanges 46 and 48 and both insulating pipes are provided. The connection with 42 and 44 is O
It is sealed with packings 52 to 55 such as rings. Both metal flanges 46 and 48 are provided with holes 47 and 49 communicating with the inner insulating tube 42, respectively. The metal flange 46 is provided with an exhaust port 50 for evacuating the space between the inner insulating pipe 42 and the outer insulating pipe 44. One exhaust port 50 may be provided as shown in FIG. 3, but a plurality of exhaust ports 50 are preferable as shown in FIG. 4 because the conductance is improved.

The gas source 24 for supplying the above-mentioned ion source gas 26 is installed in the ground potential section.

The inner insulating tube 42 of the double insulating tube 40
One end side of which is connected to the gas source 24 by a metal pipe 32,
The other end of the inner insulating tube 42 is connected to the plasma generation unit 4 of the ion source 2 (more specifically, the plasma generation container 5 that constitutes the ion generation source) by a metal pipe 34. Both metal pipes 32 and 34 are provided in the metal flanges 46 and 48 in the holes 47 and 49 as shown in FIG. 4 in this example.
To be communicated with each other, and the connecting portions are sealed by packings 56 and 57 such as O-rings. Since one metal flange 46 of the double insulating pipe 40 is connected to the gas source 24 and the vacuum exhaust device 64 described later via the metal pipe 32 and the exhaust pipe 60 described later, they have the same potential, that is, the ground potential. Since the other metal flange 48 is connected to the plasma generation unit 4 via the metal pipe 34, it has the same potential as that of the plasma generation unit 4.
That is, the potential becomes high.

In the middle of the metal pipe 32, in this example, the above-described pressure reducing valve 28 for adjusting the supply gas pressure of the ion source gas 26, the operation valve 36 for intermittently connecting and disconnecting the ion source gas 26, and the double insulation. A pressure gauge 38 for measuring the pressure of the ion source gas 26 supplied to the tube 40 side is provided. The pressure in the metal pipe 32 of the ion source gas 26 is, for example, a related regulation (high pressure gas control law) when handling a special gas.
To less than 1 kg / mm ² G. Operation valve 36
The operating method is, for example, a pneumatic type, but other than that, an electromagnetic type, an electric type or the like may be used.

In this example, the flow rate controller 30 for controlling the flow rate of the ion source gas 26 introduced into the plasma generating section 4 is provided in the middle of the metal pipe 34.

The metal flange 48 on the high potential side of the double insulating tube 40 is further provided with a hole 51 which communicates with the space between the inner insulating tube 42 and the outer insulating tube 44. The exhaust pipe 88 connected to 70 is connected to the hole 51
Is connected to the metal flange 48 so as to communicate with, and the connecting portion is sealed by a packing 59 such as an O-ring (see FIG. 4).

Further, this ion beam irradiation apparatus is provided in the ground potential portion and is provided with the inner insulating tube 42 of the double insulating tube 40.
A vacuum evacuation device 64 for collectively evacuating the inside of the mass spectrometer 70 connected between the outer insulation pipe 44 and the outer insulation pipe 44 and via the evacuation pipe 88 is provided. The vacuum exhaust device 64 exhausts the inside of the mass spectrometer 70 to, for example, the above-mentioned 10 ⁻⁵ to 10 ⁻⁶ Torr. Due to the conductance, a somewhat higher vacuum is created between the inner insulating tube 42 and the outer insulating tube 44. The vacuum exhaust device 64 is connected to the double insulating pipe 40 by an exhaust pipe 60 made of metal in this example. The exhaust pipe 60 is
In this example, as shown in FIG. 4, the metal flange 46 is connected so as to communicate with the exhaust port 50, and the connecting portion is vacuum-sealed by a packing 58 such as an O-ring. A vacuum gauge 62 for measuring the degree of vacuum between the inner insulating pipe 42 and the outer insulating pipe 44 is provided near the double insulating pipe 40 in the middle of the exhaust pipe 60. The exhaust gas from the vacuum exhaust device 64 is exhausted to a predetermined safe place. In that case, it is preferable that the components of the ion source gas 26 that may be contained in the exhaust gas be discharged via a trap device (not shown) that captures and adsorbs the components to render them harmless.

In this ion beam irradiation apparatus, the ion source gas 26 supplied from the gas source 24 is passed through the inner insulating pipe 42 of the double insulating pipe 40 and the metal pipes 32 and 34 connected to both ends thereof, It can be directly introduced into the plasma generation unit 4 of the ion source 2 (that is, not directly supplied into the plasma generation unit 4 from the vacuum container 12 side via the extraction electrode system 8 but introduced into the plasma generation unit 4).

In addition, the plasma generation unit 4 of the ion source 2,
The electrical insulation between the gas source 24 and the vacuum exhaust device 64 installed in the ground potential section can be performed by the double insulating tube 40. That is, the plasma generator 4 is connected to the DC power source 20.
The withstand voltage against the above-mentioned high voltage applied from can be held by this double insulating tube 40.

In the unlikely event that the inner insulation tube 42 of the double insulation tube 40 itself or the connection between the inner insulation tube 42 and the metal flanges 46 and 48 (that is, around the packings 52 and 54 in FIG. 4) is deteriorated, the ion source gas may be deteriorated. Even if the leak of 26 occurs, the vacuum exhaust device 6 is provided between the inner insulating pipe 42 and the outer insulating pipe 44.
Since it is evacuated by 4, the leaked ion source gas 26 can be discharged to a predetermined safe place without being diffused around the ion beam irradiation device. Therefore, the plasma generation unit 4 to which the high voltage of the ion source 2 is applied
From the gas source 24 provided in the ground potential portion to the ion source gas 2
6 can be safely introduced. As a result, unlike the case where the gas source 24 is installed on the high-voltage pedestal as in the conventional example shown in FIG. 5 and the embodiment shown in FIG. 1, it is possible to prevent the ion beam irradiation apparatus from increasing in size. At the same time, the gas source 24 can be safely replaced.

Since the metal pipes 32 and 34 are used as the pipes between the inner insulation pipe 42 of the double insulation pipe 40 and the gas source 24 and the plasma generating portion 4, the possibility of gas leakage in the pipes is usually high. It is extremely small as in the case of the metal pipe, and there is no fear of gas leakage as in the case of the insulating pipe described above. Since the metal pipes 32 and 34 and the double insulating pipe 40 are also connected to each other at the metal flanges 46 and 48 in this example, as shown in FIG. The property is extremely small as in the case of connecting ordinary metal pipes.

Moreover, in this embodiment, as in the embodiment of FIG. 1, a dedicated insulating tube 90 and a vacuum exhaust device 92 for evacuating the inside of the mass spectrometer 70 from the ground potential portion are not provided, but the ground potential is not provided. The double insulation pipe 40 and the vacuum exhaust device 64 for safely introducing the ion source gas 26 from the gas source 24 provided in the gas analyzer 24 to the plasma generation unit 4 are used for vacuum exhaust from the ground potential part in the mass spectrometer 70. Since this is also used, the device configuration can be simplified and the device cost can be reduced.

If a gas leak should occur from the inner insulating tube 42 of the double insulating tube 40, a leak detector such as a helium detector is usually used to find the leak location, but the mass spectrometer described above is used. If a quadrupole mass spectrometer capable of ionizing and detecting the incident gas is used as 70, this mass spectrometer 70 can be used in place of the leak detector. That is, for example, the metal pipe 3
Close the valve on the side 4 and insert metal pipe 3 into the inner insulating pipe 42.
If a gas for leak detection, such as helium gas, is supplied from the second side, helium will leak between the inner insulating pipe 42 and the outer insulating pipe 44 if there is a leaked portion, and the exhaust pipe 88 will come out.
This is because it reaches the mass spectrometer 70 via and is detected. In this case, although the vacuum evacuation device 64 may be operated, it is preferable to stop the evacuation device 64 because the detection sensitivity becomes higher.

When the ion source gas 26 leaks from the inner insulating tube 42 of the double insulating tube 40 as described above, the degree of vacuum between the inner insulating tube 42 and the outer insulating tube 44 deteriorates (that is, Since the gas pressure rises), it is preferable to provide a vacuum gauge 62 to measure the degree of vacuum as in this embodiment. In this case, the leakage of the ion source gas 26 from the inner insulating tube 42 portion will occur. Can be promptly detected by the vacuum gauge 62. Further, in response to the detection of the ion source gas leak by the vacuum gauge 62, the operation valve 36 provided in the supply line of the ion source gas 26 on the ground potential side is closed,
It is preferable to shut off the ion source gas 26 on the upstream side of the double insulating tube 40. By doing so, the leakage of the ion source gas 26 can be quickly stopped. This vacuum gauge 6
The operation of closing the operation valve 36 in response to the detection of the deterioration of the degree of vacuum due to 2 is preferably performed by providing a control device 66 including a sequencer or the like as in this embodiment. Can be achieved.

Further, it is preferable to provide a pressure gauge 38 as in this embodiment to measure the gas pressure in the metal pipe 32.
By doing so, it is possible to promptly detect the damage of the inner insulating pipe 42 when the gas pressure abnormally rises due to the abnormality of the pressure reducing valve 28 and the start of the discharge inside the inner insulating pipe 42 due to the abnormal decrease of the gas pressure. can do. Further, in response to the detection of the gas pressure abnormality by the pressure gauge 38, it is preferable to close the operation valve 36 to shut off the ion source gas 26 on the upstream side of the double insulating pipe 40. It is possible to quickly prevent damage to the insulating pipe 42. The operation of closing the operation valve 36 in response to the detection of the gas pressure abnormality by the pressure gauge 38 is also preferably caused to be performed by the control device 66 as in this embodiment. By doing so, the protection operation can be automated. it can.

If a plurality of types of ion source gas 26 are supplied to the plasma generating unit 4, a plurality of holes are provided in the inner insulating tube 42 of the double insulating tube 40 and the gas is supplied as needed. From source 24 to metal line 32, and metal line 3
4 to the flow controller 30 are provided in a plurality of lines,
The metal pipes 32 and 34 may be connected to the holes of the inner insulating pipe 42, respectively.

[0055]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, the mass analysis apparatus attached to the plasma generation unit of the ion source can perform the mass analysis of the ions constituting the plasma generated in the plasma generation unit. Since the evacuation device for evacuating the inside of the mass spectrometer is provided, it is possible to accurately perform mass analysis of the ion. Since the ions and the ion beam extracted from the ion source have the same composition as each other because they are extracted from the same plasma, the ions can be accurately analyzed by mass spectrometry. The composition of the beam can be analyzed accurately.

Moreover, since the energy of the ions entering the mass spectrometer from the plasma generation unit is much smaller than the energy of the ion beam extracted from the extraction electrode system, the mass spectrometer can be downsized. That is, a small mass spectrometer is sufficient.

Further, since the vacuum exhaust device is provided in the ground potential portion, the power supply to the vacuum exhaust device is facilitated and the high voltage surge generated in the high voltage portion such as the extraction electrode system is affected. It is possible to prevent the failure and malfunction of the vacuum exhaust device due to the high voltage surge.

According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the following effect is further exerted.

That is, electrical insulation between the plasma generating portion of the ion source and the gas source and the vacuum exhaust device installed in the ground potential portion can be performed by the double insulating tube. Even if the ion source gas leaks from the portion of the inner insulating tube, the space between the inner insulating tube and the outer insulating tube is evacuated by the vacuum exhaust device. Without diffusing around
It can be discharged to a designated safe place. Therefore, the ion source gas can be safely introduced from the gas source provided in the ground potential section to the plasma generation section to which the high voltage of the ion source is applied. As a result, unlike the case where the gas source is installed on a high-voltage pedestal, it is possible to prevent the ion beam irradiation apparatus from increasing in size and to safely replace the gas source.

Moreover, since the double insulating tube and the vacuum exhaust device are also used for the vacuum exhaust in the mass spectrometer, the device structure can be simplified and the device cost can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an ion beam irradiation apparatus according to the present invention.

FIG. 2 is an enlarged sectional view showing a detailed example of the mass spectrometer in FIG.

FIG. 3 is a diagram showing another example of the ion beam irradiation apparatus according to the present invention.

FIG. 4 is an enlarged cross-sectional view showing a detailed example of the double insulating tube in FIG.

FIG. 5 is a diagram showing an example of a conventional ion beam irradiation apparatus.

[Explanation of symbols]

2 Ion source 4 Plasma generator 10 ion beam 12 Processing room 16 Irradiated object 24 gas sources 26 Ion source gas 32, 34 metal piping 40 double insulation pipe 42 Inner insulation tube 44 Outer insulation tube 64 vacuum exhaust device 70 Mass spectrometer 76 small holes 88 Exhaust pipe 90 Insulation pipe 92 Vacuum exhaust device

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-9-127060 (JP, A) JP-A-9-259778 (JP, A) JP-A-5-205685 (JP, A) JP-A-6- 36737 (JP, A) JP 5-325872 (JP, A) JP 5-82072 (JP, A) JP 10-275695 (JP, A) JP 5-67450 (JP, A) JP 10-79231 (JP, A) JP 1-309300 (JP, A) JP 2-312154 (JP, A) JP 4-12448 (JP, A) JP 2-248854 (JP, A) Actual Kaihei 2-102655 (JP, U) Special Tables 5-500286 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01J 37/317 C23C 14 / 22 C23C 14/48 H01J 27/02

Claims (2)

(57) [Claims] 1. A process of evacuating an ion beam extracted from an ion source, which generates plasma and to which a high voltage is applied, and an extraction electrode system for extracting an ion beam from the plasma, into a vacuum. In an ion beam irradiation apparatus configured to irradiate an object to be irradiated indoors, a part of ions constituting a plasma generated in the plasma generation unit of the ion source are made incident through a small hole. Mass analyzer for performing mass analysis of the ion concerned, a vacuum exhaust device provided in the ground potential part for vacuum exhausting the inside of the mass analyzer, and an exhaust pipe connecting the vacuum exhaust device and the mass analyzer. An ion beam irradiation apparatus, comprising: an insulating tube provided in the middle of the. 2. A process of evacuating an ion beam extracted from an ion source for generating plasma, to which a high voltage is applied, and an ion source having an extraction electrode system for extracting the ion beam from the plasma, to a vacuum. In an ion beam irradiation apparatus configured to irradiate an object to be irradiated indoors, a part of ions constituting a plasma generated in the plasma generation unit of the ion source are made incident through a small hole. A mass spectrometer for performing mass analysis of the ions, a gas source provided in the ground potential section for supplying an ion source gas to the plasma generating section of the ion source, an inner insulating tube and an outer insulating tube surrounding the inner insulating tube. A double insulating tube having, and one end side of the inner insulating tube of the double insulating tube is connected to the gas source and the other end side is plasma of the ion source. A metal pipe connected to the generation unit, an exhaust pipe connecting the mass spectrometer to the space between the inner insulating pipe and the outer insulating pipe of the double insulating pipe on the high potential side of the double insulating pipe, and ground. An evacuation device that is provided in the potential part and that evacuates the inside of the mass spectrometer connected between the inner insulating pipe and the outer insulating pipe of the double insulating pipe and therethrough via the exhaust pipe. An ion beam irradiation device characterized by comprising.