JP3971965B2 - Method and apparatus for supplying material gas to ion source - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of supplying a material gas to an ion source and an apparatus therefor, and more particularly, to the field of analyzers used for quantitative determination and composition analysis of various materials including semiconductors, or ion implantation for injecting ions into materials. The present invention relates to an ion source used in the field, an ion irradiation field having other effects such as sterilization by irradiating ions.
[0002]
[Prior art and problems to be solved by the invention]
For example, Japanese Patent Application Laid-Open No. 10-275695 and Japanese Patent Application Laid-Open No. 11-149981 have improved and proposed a method for supplying a material gas to an ion source. As described in these publications, the conventional method of supplying the material gas to the ion source is to install a gas cylinder filled with the material gas supplied to the ion source at the same high voltage unit as the ion source. There are a method to perform and a method to perform by installing at the earth potential.
[0003]
In the former method, where the gas cylinder is installed in the same high-voltage part as the ion source, the gas cylinder itself is installed in the high-voltage part and has the same potential as the ion source chamber, so a metal pipe can be used for the piping. It has the advantage that it becomes easy to do. However, a gas cylinder filled with a material gas to be supplied to the ion source, and a pipe including a valve and a flow rate controller for connecting the gas cylinder to the ion source must be installed together in the high voltage section. Because it was difficult to expand the space, it was necessary to make the gas cylinder as small as possible. When the gas cylinder is small, the replacement frequency of the gas cylinder increases. However, since the gas cylinder is installed in the high voltage section, it is necessary to replace the gas cylinder after stopping the operation of the ion source and lowering the voltage each time.
[0004]
On the other hand, in the method in which the latter gas cylinder is installed at the ground potential, the gas cylinder can be installed at the ground potential. Therefore, there is no restriction on the installation space as in the case where the gas cylinder is installed at the high voltage portion, and the gas cylinder can be enlarged. In addition, there is an advantage that a large number can be installed and used by switching. However, the pipe between the gas cylinder installed at the earth potential and the high voltage part needs to be insulated from the gas cylinder side by connecting the insulation pipe to the high voltage part side. There is a concern that the material gas leaks from the joint portion to the outside.
[0005]
In addition, in the case where a high voltage ion source having a high voltage of 100 kV or higher is targeted, in order to insulate the high voltage, as shown in FIGS. The accelerating tube 23 is covered with a tank 24, and SF6 gas or the like is sealed inside the tank 24 at a high pressure. In this case, in the case of the type in which the gas cylinder 25 is installed in the high voltage unit 21 (FIG. 3), the gas cylinder 25 has the same problem as the type in which the gas cylinder is installed in the high voltage unit, and each time the gas cylinder 25 is replaced, It is necessary to recover the SF6 gas in the tank 24, open and close the tank 24, and pressurize the SF6 gas again.
[0006]
On the other hand, in the case of the type in which the gas cylinder is installed at the ground potential (FIG. 4), the same problem as in the case of the type in which the gas cylinder is installed at the earth potential is concerned, but more than that, the gas cylinder 25 and the pipe 26 are connected to the tank. Since the gas cylinder 25 is enlarged or the number of gas cylinders 25 is increased, the tank 24 needs to be enlarged. When the tank 24 is enlarged, a large amount of gas such as SF6 gas to be sealed is required, which increases the cost as a whole. Further, when the insulating tube 27 is required to have a certain length and is short, creeping discharge is generated, so that the insulating tube 27 does not provide effective insulation. Further, each time the gas cylinder 25 is replaced, it is necessary to collect the SF6 gas in the tank 24, open and close the tank 24, and pressurize and supply the SF6 gas again. In FIGS. 3 and 4, 28 is an ion source, 29 is a valve, 30 is a mass flow unit composed of a material gas flow rate adjusting valve, and the like, and 31 is an extraction electrode.
[0007]
The present invention has been made by paying attention to the above-described circumstances, and the purpose thereof is to effectively use an insulating tube so that a gas cylinder can be installed outside the high-voltage section and further outside the tank. A method and apparatus for supplying a material gas to a source are provided.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention comprises the following arrangement.
[0009]
The invention according to claim 1 is a method of supplying a material gas from a gas cylinder to an ion source, wherein the gas cylinder is arranged at the ground potential portion, and the material gas supply pipe between the gas cylinder and the ion source is insulated in the middle. A gist is a method of supplying a material gas to an ion source that includes a tube and supplies the material gas from the gas cylinder to the ion source through a pipe in which the insulating tube is wound around the outer periphery of the high-voltage power source.
[0010]
Usually, it is said that the creepage distance in the atmosphere is 3 times that of space, and the creepage distance in SF6 gas is 4 to 6 times. Therefore, in order to prevent creeping discharge through the insulating tube, the length of the insulating tube needs to be at least five times longer than the spatial distance from the high voltage portion to the ground potential portion. If the insulating tube is piped, the distance from the high voltage portion to the ground potential portion is long. Therefore, in the present invention, by a pipe to the space to ground potential portion of the insulating tube from the high voltage portion formed in al linearly wound around the outer peripheral of the high voltage power supply, and to prevent creeping discharge through the insulating tube Is. Thus, the creeping discharge of the insulating tube can be prevented and the space between the high voltage portion and the ground potential portion can be shortened, so that the material gas can be safely supplied to the ion source with a compact device. In particular, in the case of an ion source using a high voltage of 100 kV or higher, a gas cylinder can be installed outside the tank, and at the same time, the interval between the high voltage part and the tank of the ground potential can be narrowed. The tank itself can be made small, and the entire apparatus can be made compact. In addition, since the gas cylinder is installed outside the tank, the gas cylinder can be enlarged and the number of installation can be increased, so that the frequency of opening and closing of the tank can be reduced, and the number of operations such as recovery and injection of SF6 gas in the tank can be reduced. .
[0016]
The invention according to claim 2 is the method of supplying a material gas to the ion source according to claim 1, wherein when the insulating tube is wound around the outer periphery of the high-voltage power source, it is between the high voltage and the ground potential, and The gist of the present invention is a method of supplying a material gas to an ion source passing through the vicinity or inside of a plurality of metals, which is attached to a high voltage power source .
[0017]
Thus, when wrapped around the outer periphery of the high pressure supply, attached to Re its, by passing near or inside the plurality of metal simply than when wound around the high pressure supply, reducing the length of the insulating tube Thus, creeping discharge can be prevented.
[0018]
According to a third aspect of the present invention, there is provided an apparatus for supplying a material gas from a gas cylinder to an ion source, a gas cylinder arranged at a ground potential portion, a material gas supply pipe between the gas cylinder and the ion source, and the material gas The gist of the present invention is an apparatus for supplying a material gas to an ion source that includes an insulating pipe connected in the middle of a supply pipe, and the insulating pipe is wound around the outer periphery of a high-voltage power source.
[0019]
Usually, it is said that the creepage distance in the atmosphere is 3 times that of space, and the creepage distance in SF6 gas is 4 to 6 times. Therefore, in order to prevent creeping discharge through the insulating tube, the length of the insulating tube needs to be at least five times longer than the spatial distance from the high voltage portion to the ground potential portion. If the insulation pipe is installed, the distance from the high voltage section to the ground potential section is long. Especially in the device for supplying the material gas to the ion source equipped with the tank, a gas cylinder is installed outside the tank. Even if it can be done, the entire device becomes larger. Therefore, in the present invention, the insulating tube is formed in al linearly wound around the outer peripheral of the high-voltage power source, by piping the insulating tube in the space from the high-voltage unit to the ground potential portion, preventing the creeping discharge through the insulating tube The entire apparatus is configured compactly. In particular, in the case of an ion source using a high voltage of 100 kV or higher, a gas cylinder can be installed outside the tank, and at the same time, the interval between the high voltage part and the tank of the ground potential can be narrowed. The tank itself can be made small, and the entire apparatus can be made compact. In addition, since the gas cylinder is installed outside the tank, the gas cylinder can be enlarged and the number of installation can be increased, so that the frequency of opening and closing of the tank can be reduced, and the number of operations such as recovery and injection of SF6 gas in the tank can be reduced. .
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram of an apparatus for supplying a material gas to an ion source according to the present invention.
[0024]
The ion source 1 and the extraction electrode 2 are installed in the high voltage unit 3. The high voltage unit 3 is connected to a high voltage power supply 4 and is held at a high voltage (for example, several hundred kV to several MV). An acceleration tube 5 is attached to the tip of the extraction electrode 2 of the high voltage unit 3. The high voltage unit 3, the high voltage power source 4, and the acceleration tube 5 are installed in the tank 6.
[0025]
On the other hand, the material gas supply device 7 to the ion source basically includes a gas cylinder 8 and a pipe 9, and one end of the pipe 9 is connected to the gas cylinder 8 and the other end is connected to the ion source 1. The gas cylinder 8 is installed in a ground potential portion outside the tank 6. The pipe 9 includes a valve 10 provided at a drawing portion of the gas cylinder 8, a mass flow portion 11 including a material gas flow rate adjustment valve, and an insulating tube 12. In this example, the insulating tube 12 is wound around the outer periphery of the high voltage power supply 4. One end of the insulating tube 12 is connected to a metal tube 13 connected to the ion source 1 and mounted in the high voltage unit 3 including the mass flow unit 11 at a place where the high voltage unit 3 exits, and the other end is A metal pipe 14 connected to the gas cylinder 8 is connected inside the tank 6.
[0026]
In the above configuration, the insulating tube 12 is formed in a spiral shape and is wound around the outer periphery of the high voltage power source 4 and is piped 9 in the space from the high voltage portion 3 to the ground potential portion (metal tube 14). The insulating tube 12 having a length that does not occur can be formed compactly, and creeping discharge through the insulating tube 12 can be prevented. Further, since the creeping discharge of the insulating tube 12 can be prevented and the space between the high voltage portion 3 and the ground potential portion (metal tube 14) can be shortened, the material gas can be safely ionized from the gas cylinder 8 with a compact device. Source 1 can be supplied. Further, since the distance between the high voltage unit 3 and the tank 6 having the ground potential can be narrowed, not only the high voltage unit 3 but also the tank 6 itself can be formed small, and the entire apparatus can be made compact. Further, since the gas cylinder 8 is installed outside the tank 6, the gas cylinder 6 can be enlarged and the number of installation can be increased, so that the frequency of opening and closing of the tank 6 can be reduced, and the SF6 gas in the tank 6 is recovered and charged. At the same time as the number of operations can be reduced, the possibility of leaking SF6 gas is low and it is environmentally friendly.
[0027]
FIG. 2 is a conceptual diagram of an apparatus for supplying a material gas to an ion source according to another embodiment of the present invention. The apparatus shown in FIG. 2 has a structure in which a high voltage power source 4 is provided with a metal ring 15 arranged at an equal electric field at a substantially equal distance between a high voltage and a ground potential on the outer periphery thereof. 1 is a device having substantially the same configuration as the device shown in FIG. 1 except that 12 is spirally provided so as to pass near or inside the metal ring 15.
[0028]
Even in the apparatus shown in FIG. 2, the same effect (paragraph number [0026]) as that of the apparatus shown in FIG. 1 can be enjoyed, and the high voltage power source 4 has a high voltage on its outer periphery. Since the metal ring 15 is disposed with a uniform electric field at an approximately equal distance from the ground potential, and the insulating tube 12 is spirally wound with the metal ring 15 interposed, the equally divided metal ring 15 is provided. Therefore, the length of the insulating tube 12 corresponding to the potential between 15 and 15 is sufficient, and the creeping discharge is made shorter than when the insulating tube 12 is wound between the high voltage and the ground potential without providing the metal ring 15. Can be prevented. The reason is as follows. That is, the creeping discharge start voltage (flashover voltage) increases as the thickness of the insulator increases, but does not become the linear ratio but increases. For example, in order to withstand a voltage of 10 kV, an insulator thickness of 2 mm or more is required, but in order to withstand a voltage of 30 kV, 6 mm which is three times 2 mm is not sufficient, and a thickness of 28 mm is required. However, the thickness of the insulator can be reduced to 6 mm by dividing the potential of 30 kV almost equally into 10 kV by the metal ring and inserting a 2 mm insulator between the three metal rings.
[0029]
In the above embodiment, the case where the mass flow part 11 is provided in the metal pipe 13 attached in the high voltage part 3 has been described as an example. However, the metal pipe 14 connected to the gas cylinder 8 placed at the ground potential. May be provided. By providing in this way, the space for providing the mass flow part 11 can be narrowed, so that the high voltage part 8 can be narrowed and the entire apparatus can be made more compact.
[0030]
In the above embodiment, the case where the insulating tube 12 is wound around the high voltage power source 4 or the case where the metal ring 15 of the high voltage power source 4 is passed has been described as an example, but the insulating tube 12 may be wound around the acceleration tube 5, Or you may make it let the metal ring of the acceleration tube 5 pass.
[0031]
【The invention's effect】
As described above, the space according to the method of supplying the material gas into the ion source of the present invention, the insulating tube is wound around the outer periphery of the high-voltage power source is formed in a spiral shape from the high-voltage unit to the ground potential portion Therefore, the creeping discharge of the insulating tube can be prevented, the space between the high voltage portion and the ground potential portion can be shortened, and the material gas can be safely supplied to the ion source with a compact device.
[0032]
According to the feeder of the material gas to the ion source of the present invention, pipe insulation tube is wound around the outer periphery of the high-voltage power source is formed in a spiral shape, the space that the insulating tube from the high voltage unit to the ground potential portion By doing so, creeping discharge through the insulating tube can be prevented, and the entire apparatus can be configured compactly. In particular, in the case of an ion source using a high voltage of 100 kV or higher, a gas cylinder can be installed outside the tank, and at the same time, the interval between the high voltage part and the tank of the ground potential can be narrowed. The tank itself can be made small, and the entire apparatus can be made compact. In addition, since the gas cylinder is installed outside the tank, the gas cylinder can be enlarged and the number of installation can be increased, so that the frequency of opening and closing of the tank can be reduced, and the number of operations such as recovery and injection of SF6 gas in the tank can be reduced. .
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a material gas supply device to an ion source according to the present invention.
FIG. 2 is a conceptual diagram of an apparatus for supplying a material gas to an ion source according to another embodiment of the present invention.
FIG. 3 is a conceptual diagram of a conventional apparatus for supplying a material gas to an ion source.
FIG. 4 is a conceptual diagram of a conventional apparatus for supplying a material gas to an ion source.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1: Ion source 2: Extraction electrode 3: High voltage part 4: High voltage power supply 5: Acceleration pipe 6: Tank 7: Supply apparatus of material gas to an ion source 8: Gas cylinder 9: Piping 10: Valve 11: Mass flow part 12 : Insulating tube 13, 14: Metal tube 15: Metal ring

Claims (3)

  A method of supplying a material gas from a gas cylinder to an ion source, wherein the gas cylinder is disposed at a ground potential portion, and a material gas supply pipe between the gas cylinder and the ion source is provided with an insulating pipe in the middle, and the insulating pipe is A material gas supply method to an ion source, characterized in that material gas is supplied from a gas cylinder to an ion source through a pipe wound around an outer periphery of a high-voltage power source.   2. The material gas to the ion source according to claim 1, wherein when the insulating tube is wound around the outer periphery of the high-voltage power source, the gas passes between the high voltage power source and the ground potential and passes through the vicinity of or inside the plurality of metals. Supply method.   An apparatus for supplying a material gas from a gas cylinder to an ion source, which is connected to a gas cylinder arranged at a ground potential portion, a material gas supply pipe from the gas cylinder to the ion source, and a middle of the material gas supply pipe An apparatus for supplying a material gas to an ion source, comprising: an insulating tube, wherein the insulating tube is wound around an outer periphery of a high-voltage power source.

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