JP3533916B2 - Ion beam irradiation equipment - Google Patents

Description

Description: 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), and a thin film formation using both ion irradiation and vacuum deposition. An ion beam irradiation apparatus that irradiates an object to be irradiated with an ion beam extracted from an ion source in a vacuum vessel, and more specifically, to a plasma generation unit to which a high voltage of the ion source is applied. And a means for safely introducing an ion source gas from a gas source provided in a ground potential portion. 2. Description of the Related Art FIG. 3 shows an example of a conventional ion beam irradiation apparatus. This ion beam irradiation apparatus includes an ion source 2
The object 16 (for example, a semiconductor substrate or a substrate for a liquid crystal display) is irradiated with the ion beam 10 extracted from the substrate 16 in the vacuum vessel 12 without mass separation, and a process such as ion implantation is performed on the object 16. Is configured to be performed. The inside of the vacuum vessel 12 is evacuated to a vacuum (for example, about 10 ⁻⁵ to 10 ⁻⁶ Torr) by the vacuum exhaust device 14. [0003] The ion source gas 2
A plasma generator 4 for generating a plasma 6 by ionizing the plasma 6 by, for example, high-frequency discharge, microwave discharge, arc discharge, etc., and an ion beam provided by the action of an electric field from the plasma 6 provided near an outlet of the plasma generator 4. And an extraction electrode system 8 for extracting the reference numeral 10. The extraction electrode system 8 has four porous electrodes in this example, and the first electrode counted from the upstream side and the plasma generation section 4 (more specifically, the plasma generation section constituting the electrode). The container 5) has a positive high voltage (for example, 10 kV to 10 kV) for extracting and accelerating the ion beam 10.
(About 200 kV) is applied from the DC power supply 20. DC voltages are applied to the second and third electrodes from DC power supplies 21 and 22, respectively, as shown in the figure. The fourth electrode and the vacuum vessel 12 are grounded. Incidentally, an ion implantation apparatus provided with a similar ion source is disclosed in, for example, Japanese Patent Application Laid-Open No. 9-92199. [0005] The ion source gas 26 is supplied to the vacuum vessel 12.
Plasma generating unit 4
In this example, the ion source gas 26 is directly introduced into the plasma generation unit 4, although there is a thought that the ion source gas 26 is supplied to the plasma generation unit 4. This is preferable because 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 a high voltage is applied to the plasma generation unit 4 as described above, conventionally, a high-voltage mount having a potential equivalent to that of the plasma generation unit 4 is supported by an insulator from the ground potential portion. A gas source (for example, a gas cylinder) 24 and the like are 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 generation unit 4 are connected to the metal pipe 2.
7 and the pressure reducing valve 28 and the flow controller 3
0, and all of them are provided on the high-voltage mount. The ion source gas 26 is, for example, PH ₃ (phosphine), B ₂ H ₆ (diborane), or the like in the case of manufacturing a semiconductor device (specifically, injecting impurities into a semiconductor).
A gas such as AsH ₃ (arsine) or a gas obtained by diluting them with hydrogen or the like. The gas source 24 is considerably large because it is necessary to reduce the frequency of replacement of the gas source 24 to prevent a decrease in the throughput of the ion beam irradiation apparatus.
When the supply amount of the ion source gas 26 to the plasma generation unit 4 is increased to extract a large amount of the ion beam 10, the size becomes further larger. For this reason, when the gas source 24 is installed on the high-voltage gantry as described above, the high-voltage gantry becomes large,
Eventually, the insulating space surrounding the high-voltage gantry becomes large, and the device becomes large. [0010] The high-voltage mount provided on the insulator is
It is located at a relatively high position from the floor (ground potential portion), and replacing the large gas source 24 at such a high position is not preferable in terms of safety. Unlike the above conventional example, a gas source 24 is installed in the ground potential portion, an insulating pipe is provided in the middle of a metal pipe 27, and this insulating pipe insulates a high voltage applied to the plasma generator 4. There is also the idea. Although it is preferable to install the gas source 24 at the ground potential portion in terms of miniaturization of the apparatus and safety in handling the gas source 24, if the high voltage is simply insulated by the insulating pipe, Leakage of the ion source gas 26 from the insulating piping portion is not preferable for safety. This is because, for example, in the case of semiconductor device manufacturing and the like, a toxic gas (for example, PH ₃ , B ₂ H ₆ , AsH _3, etc. described above) may be used as the ion source gas 26, This is because the insulating pipe generally has a lower mechanical strength than the metal pipe and easily causes gas leakage. For example, the material of the insulating pipe is usually a resin such as a fluororesin or a ceramic such as alumina. In the case of resin, gas leakage is likely to occur due to the degree of tightening because the resin is easily deformed. Further, when a high voltage is applied to cause creeping discharge, carbonization may occur to cause gas leakage, and in some cases, a hole is formed. In the case of ceramics, since they are brittle, cracks and cracks are likely to occur due to external force, which may cause gas leakage. SUMMARY OF THE INVENTION Accordingly, it is a main object of the present invention to safely introduce an ion source gas from a gas source provided at a ground potential portion into a plasma generating section to which a high voltage of an ion source is applied. An ion beam irradiation apparatus according to the present invention comprises a gas source provided at a ground potential portion for supplying the ion source gas, an inner insulating tube and an outer insulating tube surrounding the same. And one end of the inner insulating tube of the double insulating tube is connected to the gas source via a remote control type operation valve, and the other end is connected to the plasma generator of the ion source. A metal pipe, which is provided in a ground potential portion and evacuates a space between an inner insulating pipe and an outer insulating pipe of the double insulating pipe, is provided with a second vacuum pump different from the first vacuum pumping apparatus.
A vacuum exhaust system, the inner insulating tube and the outside of the double insulation tube
A vacuum gauge for measuring the degree of vacuum between the insulating tube and the vacuum gauge
The degree of vacuum is smaller than a predetermined value based on the degree of vacuum measured in
A control device that performs control to close the operation valve when it deteriorates
And characterized in that: According to the above configuration, the ion source gas supplied from the gas source is introduced into the plasma generator of the ion source through the inner insulating tube of the double insulating tube and the metal pipes connected to both ends thereof. be able to. Further, the electrical insulation between the plasma generation part of the ion source and the gas source provided at the ground potential part can be performed by a double insulating tube. Even if the ion source gas leaks from the inner insulating tube part, the space between the inner insulating tube and the outer insulating tube is evacuated by the vacuum exhaust device. It can be discharged to a predetermined safe place without diffusing around the beam irradiation device. Therefore, the ion source gas can be safely introduced from the gas source provided at the ground potential portion into the plasma generating portion to which the high voltage of the ion source is applied. 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 double insulating tube in FIG. FIG.
The same or corresponding parts as those of the conventional example are denoted by the same reference numerals, and differences from the conventional example will be mainly described below. This ion beam irradiation apparatus includes 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. The two 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, a high voltage as described above applied from the DC power supply 20 to the plasma generation unit 4 of the ion source 2. It has withstand voltage. As shown in FIG. 2, metal flanges 46 and 48 are provided at both ends of the inner insulating tube 42 and the outer insulating tube 44, respectively. The connection with 42 and 44 is O
It is sealed (sealed) by packings 52 to 55 such as rings. The two 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 tube 42 and the outer insulating tube 44. Although one exhaust port 50 may be provided as shown in FIG. 1, a plurality of exhaust ports 50 are preferably used as shown in FIG. 2 because the conductance is improved. The gas source 24 for supplying the above-mentioned ion source gas 26 is installed at the ground potential portion. The inner insulating tube 42 of the double insulating tube 40
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 generating unit 4 of the ion source 2 (more specifically, the plasma generating container 5 constituting the same) by a metal pipe 34. As shown in FIG. 2, both metal pipes 32 and 34 are provided in the metal flanges 46 and 48 with the holes 47 and 49, respectively.
Are connected so as to communicate with each other, and the connection portions are sealed by packings 56 and 57 such as O-rings. The one metal flange 46 of the double insulating pipe 40 is connected to the gas source 24 and a vacuum exhaust device 64 described later via the metal pipe 32 and an exhaust pipe 60 described later, so that it has 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,
That is, the potential becomes high. In the present embodiment, 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 remotely controlling the on / off of 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 is provided. The pressure of the ion source gas 26 in the metal pipe 32 may be determined, for example, by a related regulation when handling a special gas (high pressure gas control law).
Is maintained at less than 1 kg / mm ² G according to Operation valve 36
The operation method is, for example, pneumatic, but may be electromagnetic, electric, or the like. In the present embodiment, the flow 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. Further, the ion beam irradiation apparatus is provided at the ground potential portion, and is provided on the inner insulating tube 42 of the double insulating tube 40.
For example, between 10 ^{-4 and} 10 ^-6 Torr.
An evacuation device 64 for evacuating to about r is provided.
The vacuum exhaust device 64 is connected to the double insulating pipe 40 by an exhaust pipe 60 made of metal in this example. As shown in FIG. 2 in this example, the exhaust pipe 60 is connected to the metal flange 46 so as to communicate with the exhaust port 50, and the connection portion is vacuum-sealed by a packing 58 such as an O-ring. . A vacuum gauge 62 that measures the degree of vacuum between the inner insulating tube 42 and the outer insulating tube 44 is provided near the double insulating tube 40 in the middle of the exhaust pipe 60.
The exhaust gas from the vacuum exhaust device 64 is discharged to a predetermined safe place. In this case, it is preferable that the exhaust gas is discharged through a trap device (not shown) that captures and adsorbs a component of the ion source gas 26 that may be contained in the exhaust gas and renders it harmless. In this ion beam irradiation apparatus, the ion source gas 26 supplied from the gas source 24 is passed through the inner insulating tube 42 of the double insulating tube 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 (ie, not directly into the plasma generation unit 4 but from the vacuum vessel 12 via the extraction electrode system 8 via the extraction electrode system 8). The electrical insulation between the plasma generating section 4 of the ion source 2 and the gas source 24 installed at the ground potential section is as follows.
This can be performed by the double insulating tube 40. That is, the withstand voltage against the above-described high voltage applied from the DC power supply 20 to the plasma generation unit 4 can be maintained by the double insulating tube 40. In the unlikely event that the inner insulating tube 42 itself of the double insulating tube 40 and the connection between the inner insulating tube 42 and the metal flanges 46 and 48 (that is, around the packings 52 and 54 in FIG. 2) deteriorate, the ion source gas is removed therefrom. 26, a vacuum exhaust device 6 is provided between the inner insulating tube 42 and the outer insulating tube 44.
Since the gas is evacuated by the pump 4, the leaked ion source gas 26 can be discharged to a predetermined safe place without diffusing around the ion beam irradiation device. Therefore, the plasma generator 4 to which the high voltage of the ion source 2 is applied
And the ion source gas 2 from the gas source 24 provided in the ground potential portion.
6 can be safely introduced. As a result, unlike the case where the gas source 24 is installed on a high-voltage gantry as in the conventional example shown in FIG. 3, it is possible to prevent the ion beam irradiation apparatus from being enlarged, and to replace the gas source 24. It can be done safely. Since the metal pipes 32 and 34 are used for the pipes between the inner insulating pipe 42 of the double insulating pipe 40 and the gas source 24 and the plasma generating section 4, there is a possibility that gas leaks in the pipes. Is extremely small as in the case of ordinary metal piping, and there is no concern about gas leakage as in the case of the insulating piping described above. In this example, the connection between the metal pipes 32 and 34 and the double insulating pipe 40 is made of metal at the metal flanges 46 and 48 as shown in FIG. The performance is extremely low as in the case of the connection of ordinary metal piping. 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 (ie, the degree of vacuum between the inner insulating tube 42 and the outer insulating tube 44 deteriorates). Since the gas pressure rises), it is preferable to measure the degree of vacuum by providing a vacuum gauge 62 as in this embodiment. In this case, leakage of the ion source gas 26 from the inner insulating tube 42 is prevented. Can be quickly 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 on the supply line on the ground potential side of the ion source gas 26 is closed, and the ion source gas 26 is It is preferable to shut off upstream, so that the ion source gas 2
6 can be stopped immediately. The operation of closing the operation valve 36 in response to the detection of the deterioration of the degree of vacuum by the vacuum gauge 62 is preferably performed by providing a control device 66 composed of a sequencer or the like as in this embodiment. The operation can be automated. It is preferable to provide a pressure gauge 38 to measure the gas pressure in the metal pipe 32 as in this embodiment.
By doing so, it is possible to quickly detect the breakage of the inner insulating tube 42 when the gas pressure rises abnormally due to the abnormality of the pressure reducing valve 28, and the start of the discharge inside the inner insulating tube 42 due to the abnormal decrease in the gas pressure. can do. Further, in response to the detection of the gas pressure abnormality by the pressure gauge 38, it is preferable that the operation valve 36 be closed to shut off the ion source gas 26 on the upstream side of the double insulating tube 40. Breakage of the insulating tube 42 can be promptly prevented. 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 performed by the control device 66 as in this embodiment, so that the protection operation can be automated. it can. In the case of supplying a plurality of types of ion source gases 26 to the plasma generating section 4, a plurality of holes are provided in the inner insulating tube 42 of the double insulating tube 40 as necessary, From source 24 to metal tubing 32 and metal tubing 3
A plurality of lines are provided from 4 to the flow controller 30, respectively.
Each metal pipe 32 and 34 may be connected to each hole of the inner insulating pipe 42, respectively. As described above, according to the present invention, the electrical insulation between the plasma generating portion of the ion source and the gas source provided at the ground potential portion can be performed by the double insulating tube. . Also, even if the ion source gas leaks from the inner insulating tube portion of the double insulating tube, the space between the inner insulating tube and the outer insulating tube is evacuated by the second vacuum exhaust device. The discharged ion source gas can be discharged to a predetermined safe place without diffusing around the ion beam irradiation device. Therefore, the ion source gas can be safely introduced from the gas source provided at the ground potential portion into the plasma generating portion to which the high voltage of the ion source is applied. As a result, unlike the case where the gas source is installed on the high-voltage gantry as in the conventional example, it is possible to prevent the ion beam irradiation apparatus from being enlarged, and to safely exchange the gas source. In addition, ions from the inner insulating tube part of the double insulating tube
Leakage of source gas, inner insulation tube and outer insulation tube of double insulation tube
Quickly detected by a vacuum gauge that measures the degree of vacuum between
And shut off the leakage immediately by closing the operation valve.
The operation of closing the operation valve can be controlled by the control device.
Therefore, the protection operation can be automated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an example of an ion beam irradiation device according to the present invention. FIG. 2 is an enlarged sectional view showing a detailed example of a double insulating tube in FIG. 1; FIG. 3 is a diagram illustrating an example of a conventional ion beam irradiation apparatus. [Description of Signs] 2 Ion source 4 Plasma generator 10 Ion beam 12 Vacuum container 16 Irradiated object 24 Gas source 26 Ion source gas 32, 34 Metal pipe 40 Double insulating pipe 42 Inner insulating pipe 44 Outer insulating pipe 64 Vacuum exhaust apparatus

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 14/00-14/58 C23C 16/00-16/56 H01J 37/00

Claims (1)

(1) Claims 1. An ion source gas is introduced into a plasma generation unit to which a high voltage of an ion source is applied, and an ion beam extracted from the ion source is supplied to a first evacuation device. True by
An ion beam irradiation apparatus configured to irradiate an object to be irradiated in a vacuum container to be evacuated, comprising: a gas source provided at a ground potential portion for supplying the ion source gas; an inner insulating tube and an outer insulating tube surrounding the same; A double insulated pipe having a pipe, and one end of an inner insulating pipe of the double insulated pipe is remotely operated.
A metal pipe connected to the gas source via a valve operation and the other end connected to a plasma generation unit of the ion source; an inner insulating pipe and an outer insulating pipe of the double insulating pipe provided in a ground potential part; the be those for evacuating the space between the
A further second vacuum exhaust system and the first vacuum exhaust system, the vacuum between the inner insulating tube and the outer insulating tube of the double insulation tube
A vacuum gauge for measuring the degree, the degree of vacuum Tokoro based on the degree of vacuum measured by the vacuum gauge
Control to close the operation valve when it becomes worse than the fixed value
Cormorant controller and the ion beam irradiation apparatus comprising: a.