JP5105775B2 - Insulating piping, plasma processing apparatus and method - Google Patents

Description

The present invention relates to a plasma processing method and apparatus using an insulating pipe and an insulating pipe for insulating between an ionization chamber and a gas introduction system.
In particular, the present invention relates to a plasma processing apparatus and method in which a high voltage is applied to an insulating pipe and a gas introduction unit such as an ion irradiation apparatus, an ion implantation apparatus, an ion milling apparatus, and an ion beam processing apparatus.

There are ion beam implantation equipment, ion milling equipment, ion beam processing equipment, etc. as devices that turn source gas into plasma, accelerate it by applying a high voltage to it, and irradiate the sample as an ion beam. It will be called a plasma processing apparatus.
In the plasma processing apparatus, there are various modes such as an ionization method, a gas type, and a gas pressure.
Also, ionization methods include those using high frequency, microwaves, filaments, and electron guns. In any case, a high voltage is applied to the ion source.
Therefore, the source gas must be connected to a high voltage ionization chamber.

Conventionally, in a plasma processing apparatus in which the gas pressure in an ionization chamber is about 10 ⁻² Pa to 10 Pa, the following two modes are known when supplying gas from a gas cylinder to an ion source at a high voltage.
That is, one is a gas cylinder high potential system in which a gas cylinder is provided at a high potential (see, for example, Patent Document 1), and the other is a gas cylinder ground potential system in which a gas cylinder is provided at a ground potential (for example, Patent Document 2). reference).

Hereinafter, each of these methods will be described.
(1) Gas cylinder high potential system In this system, the gas cylinder is installed at the same potential as the ionization chamber. This eliminates the need for insulation between the ionization chamber and the gas cylinder.
Next, a plasma processing apparatus using an ECR plasma apparatus as an ion source will be described as an example of a gas cylinder high potential method with reference to FIG.
In FIG. 2, when a microwave is incident on the vacuum window 203 through the waveguide 202 while a current is passed through the coil 201 to generate a magnetic field, a plasma 205 is generated in the ionization chamber 204.
At this time, the ionization chamber 204 and the processing chamber 206 are evacuated by the exhaust device 207.
At the same time, the raw material gas adjusted to an arbitrary flow rate is introduced from the gas cylinder 208 through the metal pipe 210 into the ionization chamber 204 via the gas flow rate controller 209.
At that time, the pressure in the ionization chamber 204 is about 0.05 to 0.5 Pa.
In order to accelerate the ions and irradiate the sample 211, the processing chamber 206 is set to the ground potential, and the ionization chamber 204 is set to a high potential of 1 KV or more by the acceleration power source 212.
The ionization chamber 204 and the processing chamber 206 are insulated from each other by an insulator 213.
Similarly, by applying an arbitrary potential to the grid conductive plates 214, 215, and 216 that are insulated from each other, ions 217 are extracted from the plasma 205, accelerated, and irradiated on the sample 211.
Since the gas introduction system such as the metal pipe 210, the gas cylinder 208, and the gas flow rate controller 209 are all at the same high potential as the ionization chamber, the whole is placed on the high voltage base 218 and insulated from the ground potential.

(2) Gas cylinder ground potential system In this system, an insulating pipe is provided between a gas cylinder and an ionization chamber having a high potential of 1 KV or more to insulate the gas cylinder as a ground potential.
Next, a plasma processing apparatus using an ECR plasma apparatus as an ion source will be described using FIG. 3 as an example of a grounding gas gas cylinder.
In FIG. 3, when a microwave is incident on the vacuum window 303 through the waveguide 302 while a current is passed through the coil 301 to generate a magnetic field, a plasma 305 is generated inside the ionization chamber 304.
At this time, the ionization chamber 304 and the processing chamber 306 are evacuated by the exhaust device 307.
At the same time, the raw material gas adjusted to an arbitrary flow rate is introduced from the gas cylinder 308 through the metal pipe 310 into the ionization chamber via the gas flow rate controller 309.
At that time, the pressure in the ionization chamber 304 is about 0.05 to 0.5 Pa.
In order to accelerate ions and irradiate the sample 311, the processing chamber 306 is set to the ground potential, and the ionization chamber 304 is set to a high potential by the acceleration power source 312.
The ionization chamber 304 and the processing chamber 306 are insulated from each other by an insulator 313.
Similarly, by applying an arbitrary potential to the grid conductive plates 314, 315, and 316 that are insulated from each other, ions 317 are extracted from the plasma 305, accelerated, and irradiated on the sample 311.
At this time, since the gas cylinder 308 is at the ground potential, the gas cylinder 308 and the gas flow controller 309 are insulated by the insulating pipe 318, and the gas flow controller 309 and the metal pipe 310 have the same voltage as the ionization chamber. Place on high voltage pedestal 319.
Further, the gas pressure inside the insulating pipe 318 is adjusted to about 10 ³ Pa to 10 ⁵ Pa in order to prevent discharge.
Japanese Patent Laid-Open No. 10-79231 Japanese Patent Laid-Open No. 10-275695

However, the conventional gas cylinder high potential system and gas cylinder ground potential system have the following problems, respectively.
First, in the gas cylinder high potential system, a large space for a high voltage gantry is required to install the entire gas introduction system including the gas cylinder at a high potential.
In addition, an electric wire cannot be used for communication and control between the valve or the flow rate controller and the control device, and an expensive communication means such as an optical fiber is required.
In addition, a complicated interlock for ensuring the safety of work must be provided.
As a result, the apparatus becomes very large and complicated, and the price is high. Furthermore, if the gas cylinder placed on the high-voltage gantry becomes empty, the temporary device must be stopped and the gas cylinder must be replaced after turning off the high-voltage power supply, leading to a decrease in throughput. .

Next, in the gas cylinder ground potential system, valves and gas flow rate controllers are at a high potential, so a high voltage base that is somewhat wide is also required.
In particular, when several kinds of source gases are mixed and used at an arbitrary ratio, the number of insulators required for the number of source gas types is required.
Further, as in the case of the gas cylinder high potential method, an electric wire cannot be used for communication and control between the valve and the flow rate controller and the control device, and an expensive communication means such as an optical fiber is required.
In addition, since a complicated interlock or the like for ensuring the safety of work must be provided, the apparatus becomes very large and complicated, resulting in a high price.
Further, when plastic or the like is used as the insulating pipe, the gas permeability is large and impurities are mixed, which is not suitable for a highly accurate process.
In addition, the use of ceramics is not only more expensive, but also the pressure inside the insulated piping must be relatively high to prevent discharge, so the mechanical strength of the ceramic is weak, which hinders safety. Will be affected.

In view of the above-mentioned problems, the present invention uses an insulating pipe that can save space and cost and can improve operability, and an insulating pipe that insulates between the ionization chamber and the gas introduction system. An object of the present invention is to provide a plasma processing apparatus and method.

In order to solve the above-mentioned problems, the present invention provides a plasma processing apparatus and method using an insulating pipe configured as follows, and an insulating pipe for insulating an ionization chamber and a gas introduction system.
The insulated pipe of the present invention is an insulated pipe in which both ends of the pipe are electrically insulated,
Metal flanges with openings, spaced apart;
An insulator disposed between the metal flanges arranged at intervals, and
In the space formed by the metal flange and the insulator,
Dividing the metal plate having a half-moon shaped opening so that the internal flow path does not become a straight line by arranging a plurality of the openings so that the openings are at different positions,
In the divided space, having said metal flange with a plurality of openings which are conductive, at intervals discharge under pressure does not occur in the insulation pipe, and the porous conductive plate arranged to overlap a plurality of sheets,
It is characterized by having.
Moreover, the insulating pipe of the present invention is characterized in that a spacer is disposed between the porous conductive plates.
The plasma processing apparatus of the present invention includes an ionization chamber and a gas introduction system for introducing a source gas into the ionization chamber,
The insulating pipe according to any one of the above, which insulates between the ionization chamber and the gas introduction system.
Further, the plasma processing method of the present invention includes an ionization chamber and a gas introduction system, and a raw material gas is introduced into the ionization chamber from the gas introduction system, and a sample is processed with plasma generated in the ionization chamber. In the processing method,
Insulating between the ionization chamber and the gas introduction system by an insulating pipe, and when introducing the source gas into the ionization chamber through the insulating pipe,
As the insulating pipe, metal flanges having openings arranged at intervals, and
An insulator disposed between the metal flanges arranged at intervals, and
In the space formed by the metal flange and the insulator,
Dividing the metal plate having a half-moon shaped opening so that the internal flow path does not become a straight line by arranging a plurality of the openings so that the openings are at different positions,
In the divided space, having said metal flange with a plurality of openings which are conductive, at intervals discharge under pressure does not occur in the insulation pipe, and the porous conductive plate arranged to overlap a plurality of sheets,
It is characterized by using an insulating pipe having

According to the present invention, space saving and cost reduction can be achieved, and an insulation pipe that insulates between an ionization chamber and a gas introduction system that can improve operability, and a plasma processing apparatus using the insulation pipe And methods can be realized.

The above configuration can achieve the object of the present invention, which is based on the following knowledge of the present inventors.
In general, when parallel plate electrodes are provided in a gas atmosphere and a voltage is applied between them, the relationship between the voltage at which discharge starts, the gas pressure, and the distance between the electrodes is given a good approximation by Paschen's law. It is known that
According to Paschen's law, assuming that the distance between electrodes is D, the gas pressure is P, and the discharge start voltage is Vs, Vs is determined as a function of the product P · D of P and D.
An overview of this function is shown in FIG. As shown in FIG. 4, the curve of V _s with respect to P · D is V-shaped, and there is P · D _m where Vs has the minimum value V _sm, and this V _sm is called the minimum spark voltage. .
In a region where the pressure is sufficiently high, such as under atmospheric pressure, discharge can be prevented relatively easily by increasing the inter-electrode distance D and increasing P · D.
However, in the region of gas pressure of 10 ⁻² Pa to 10 Pa, which is generally said to easily cause discharge, when an insulated pipe designed for the purpose of preventing discharge under atmospheric pressure is used, P · D becomes this P _-Since it is close to _Dm , discharge easily occurs at a low voltage.
Also, if the insulator is lengthened under such a pressure that is likely to cause a discharge and the discharge is prevented by increasing P · D, the required length of the insulator becomes very large, resulting in a cost increase. In addition, the device space is disadvantageous.

In order to solve such problems, the present invention comprises an insulating pipe that can prevent discharge even when the distance D between the electrodes is narrowed and P · D is sufficiently smaller than P · D _m. is there.
That is, a conductive plate or a mesh conductive plate (hereinafter referred to as a porous conductive plate) having a plurality of openings is used as an electrode in an insulated pipe, thereby reducing space and cost and improving operability. Made possible.
In the present embodiment, when the source gas is introduced into the ionization chamber at a high potential of, for example, 1 kV or higher in the plasma processing apparatus, the insulating pipe using such a porous conductive plate is used in the following plasma processing apparatus. It can be used as insulating piping.
For example, the gas cylinder and the gas flow controller can be provided at the ground potential, and can be used as an insulating pipe constituting a part of the pipe connecting the gas flow controller and the ionization chamber.

Hereinafter, embodiments of the plasma processing apparatus of the present invention will be described.
[First Embodiment]
In this embodiment, a configuration example of an insulating pipe of a plasma processing apparatus using a porous conductive plate having a small opening will be described.
FIG. 5A is a diagram for explaining an electric field in a conventional insulated pipe, and FIG. 5B is a diagram for explaining an electric field in an insulated pipe using the porous conductive plate in the present embodiment.

As shown in FIG. 5 (a), when a cylindrical metal flange 501 used in a general insulator becomes an electrode, the electric field created by the electrode becomes 502, The distance that the electrons can fly is longer than the distance D between the metal flanges.
On the other hand, in this embodiment, as shown in FIG. 5B, by using a porous conductive plate 503 having a sufficiently small opening, the electric field 504 created by them becomes an electric field closer to a parallel plate. .
When such a porous conductive plate is used, the conductance of the pipe decreases due to the porous conductive plate, and discharge easily occurs when the gas pressure in the insulating pipe rises. In order to increase the size, it is preferable to increase the number of openings as much as possible.

FIG. 6 shows a specific configuration of the insulation piping of the plasma processing apparatus in the present embodiment designed based on the above.
In FIG. 6, an insulator 601 is disposed between metal flanges 602 and 603, and a space is formed by the metal flanges 602 and 603 and the insulator 601.
The porous conductive plate 604 is electrically connected to the metal flanges 602 and 603, respectively.
The length of the insulator 601 is sufficiently long so that discharge does not occur under atmospheric pressure, and conversely, the distance between the porous conductive plates is sufficiently small so that discharge does not occur under pressure in the insulating pipe. .

Next, the result of the withstand voltage test performed using this insulated piping is shown in FIG.
FIG. 7 is a plot of the relationship between the pressure in the insulator and the discharge start voltage when the distance between the porous conductive plates is 0.5 mm, 1 mm, 2 mm, 5 mm, 10 mm, 20 mm, and 50 mm.
The porous conductive plate used in this test is a φ200 mm porous conductive plate having a plurality of openings having a hole diameter of φ0.5 mm and a pitch of 1 mm. The insulator is cylindrical alumina and the length is 150 mm. The gas introduced into the insulating pipe is argon gas.
FIG. 7 shows that this insulated pipe has the highest withstand voltage when the distance between the porous conductive plates is 1 mm in this test.

[Second Embodiment]
In this embodiment, a configuration example of an insulating pipe that can obtain a higher withstand voltage will be described.
FIG. 8 shows the configuration of the insulating piping in the present embodiment.
FIG. 8 shows the insulating pipes 802 and 803 adjacent to each other by stacking a plurality of insulating plates shown in FIG. 6 with a conductive plate 801 having an opening without overlapping the openings of adjacent conductive plates. , 804 is connected in multiple stages so that the internal flow path does not become a straight line.

FIG. 9 shows the results of a withstand voltage test performed using this multistage insulating pipe.
FIG. 9 is a plot of the relationship between the pressure in the insulator and the discharge start voltage when the number of stages of insulating piping is one, two, and three.
The porous conductive plate used in this test is a φ200 mm porous conductive plate having a plurality of openings with a hole diameter of 0.5 mm and a pitch of 1 mm, and the insulator is cylindrical alumina and has a length of 100 mm.
The distance between the porous conductive plates is all 1 mm. In this test, three metal plates with a thickness of 1 mm having a half-moon shaped opening are used so that the internal flow paths of adjacent insulating pipes do not become straight. The gas introduced into the insulating pipe is argon gas.
From FIG. 9, it can be seen that the withstand voltage is proportional to the number of stages of the insulating pipes when the insulating pipes are multistage in this way.
In this test, a plurality of metal plates were used so that the internal flow paths of adjacent insulating pipes were not straight, but the present invention is not limited to such a configuration.
For example, in addition to this, as shown in FIG. 10, the configuration is also the same by using a bent metal pipe 1001 such as an elbow or a flexible pipe so that the internal flow paths of adjacent insulating pipes 1002 and 1003 are not straight. The effect of.

[Third Embodiment]
In the present embodiment, an example in which an insulating flange of another form that can obtain a high withstand voltage is configured will be described.
FIG. 11 shows the configuration of the insulating flange in the present embodiment.
In this embodiment, the insulator 1101 is sandwiched between metal flanges 1102 and 1103.
A stepped process is applied to the inner surface of the insulator, and a plurality of porous conductive plates 1104 are provided on each step.
The porous conductive plates at both ends are electrically connected to the metal flanges 1102 and 1103.

The positional relationship of the holes of the porous conductive plate 1104 will be described with reference to FIG.
If the positions of the holes of adjacent porous conductive plates 1201, 1202, 1203, and 1204 match as shown in FIG. 12A, the distance between the conductive plates is locally increased, and discharge is likely to occur. End up.
Therefore, by sufficiently shifting the opening positions of adjacent porous conductive plates 1205, 1206, 1207, and 1208 as shown in FIG. 12B, the distance between the conductive plates of the porous conductive plate is the longest distance between the conductive plates. Can be almost twice as large as.
In this case, the hole diameter of the conductive plate may be large, and if the hole diameter is sufficiently large, the conductance is unlikely to be impaired, so the number of holes may be small.
Furthermore, by increasing the number of porous conductive plates, the withstand voltage can be increased in proportion to the number of conductive plates, as in the case of FIGS.
Here, when the resistance value of the insulator is too high, the porous conductive plate is charged, and as a result, the withstand voltage of the insulating pipe is lowered.
Therefore, it is necessary to devise such as using a material having a resistance value not too high for the insulator, sandwiching a spacer of a low resistance material between the porous conductive plates, or coating the inner surface of the insulator with an antistatic film.

FIG. 13 shows the result of a withstand voltage test performed using this insulating flange.
FIG. 13 is a plot of the relationship between the pressure in the insulator and the discharge start voltage when the number of porous conductive plates is 3, 5, and 10.
The porous conductive plate used for this test is a φ200 mm conductive plate having a plurality of openings with a hole diameter of φ1.0 mm and a pitch of 3.0 mm, and the distance between the porous conductive plates is all 0.5 mm.
Also, the openings of adjacent porous conductive plates are all designed to be shifted by 2.5 mm.
The insulator is made of alumina whose volume resistivity is adjusted to about 10 ⁹ Ω · cm for the purpose of preventing charging of the porous conductive plate, and the length is 100 mm. The gas introduced into the insulating pipe is argon gas.
FIG. 13 shows that the withstand voltage increases as the number of porous conductive plates increases.
Further, the withstand voltage can be further increased by providing a multi-stage insulating pipe having a plurality of such porous conductive plates as shown in FIGS.

Examples of the present invention will be described below.
[Example 1]
In Example 1, an ion milling apparatus configured by applying the first embodiment as an insulating pipe will be described.
FIG. 1 is a diagram illustrating the configuration of an ion milling apparatus according to this embodiment.
FIG. 1A is a diagram showing an outline of an ion milling apparatus using an ECR plasma system as an ion source, and FIG. 1B is a diagram showing an outline of an insulating pipe used in this embodiment.

In FIG. 1A, when a 2.45 GHz microwave is incident on the vacuum window 103 through the waveguide 102 while passing a current through the coil 101 to generate a magnetic field, a plasma 105 is generated in the ionization chamber 104.
At this time, the ionization chamber 104 and the processing chamber 106 are evacuated by the exhaust device 107. At the same time, the source gas adjusted to an arbitrary flow rate from the gas cylinder 108 via the gas flow rate controller 109 is introduced into the ionization chamber 104 through the metal pipe 110.
There are four kinds of raw material gases, Ar, Xe, Kr, and N ₂ . The pressure in the ionization chamber 104 during operation is about 0.12 to 0.43 Pa.

A high voltage of 0.5 kV to 15 kV is applied between the sample 111 at the ground potential and the ionization chamber 104 by the acceleration power source 112.
The ionization chamber 104 and the processing chamber 106 are insulated from each other by an insulator 113.
Similarly, by applying an arbitrary potential to the grid conductive plates 114, 115, and 116 that are insulated from each other, ions are extracted from the plasma, accelerated, and irradiated on the sample 111.
The gas introduction system such as the gas cylinder 108, the gas flow rate controller 109, and the valve 122 is at the ground potential, and is insulated from the ionization chamber by the insulating pipe 117 downstream from the valve 122.

As shown in FIG. 1B, the insulator 118 constituting the insulating pipe 117 is made of cylindrical alumina, and has a diameter of 120 mm, a diameter of 100 mm, and a length of 50 mm.
The two porous conductive plates 121 connected to the metal flanges 119 and 120 are stainless steel plates having an outer diameter of φ99 mm having a plurality of openings with a hole diameter of 0.2 mm and a pitch of 0.4 mm, and the distance between the porous conductive plates is 1 mm. It is said that.
The porous conductive plate 121 is subjected to an electric field polishing treatment so that electron field emission does not occur.
When this apparatus was used and a withstand voltage test was performed in the range of 0.5 kV to 15 kV in an actual use state, no discharge occurred in the insulating pipe 117.

[Example 2]
In Example 2, an ion milling device configured by applying the second embodiment as an insulating pipe and applying the third embodiment as an insulating flange will be described.
FIG. 14 is a diagram illustrating the configuration of the ion milling apparatus according to the present embodiment.
FIG. 14A is a diagram showing an outline of an ion milling apparatus using an ECR plasma system as an ion source.
Moreover, FIG.14 (b) is sectional drawing which shows the outline of the insulation piping used for a present Example.
FIG. 14C is a cross-sectional view schematically showing an insulating flange used in this embodiment, and FIG. 14D is a plan view thereof.

In FIG. 14A, when a high frequency of 13.56 MHz is applied to the antenna 1403 provided on the surface of the quartz tube 1402 while applying a current to the coil 1401 to generate a magnetic field, plasma 1405 is generated in the ionization chamber 1404. To do.
At this time, the ionization chamber 1404 and the processing chamber 1406 are evacuated by the exhaust device 1407.
At the same time, the raw material gas adjusted to an arbitrary flow rate is introduced from the gas cylinder 1408 through the metal pipe 1410 into the ionization chamber 1404 via the gas flow rate controller 1409.
There are five kinds of source gases used: Ar, O ₂ , SF ₆ , CF ₄ , and NF ₃ . The pressure in the ionization chamber 1404 during operation is about 1.2 to 4.8 Pa.

A high voltage of 5 kV to 50 kV is applied between the sample 1411 at the ground potential and the ionization chamber 1404 by the acceleration power supply 1412.
The ionization chamber 1404 and the processing chamber 1406 are insulated from each other by an insulator 1440.
The ion beam 1415 is extracted from the plasma 1405 by the lead conductive plate 1413 and the focusing lens 1414 provided therein, and is focused and irradiated onto the sample 1411.
The gas introduction system such as the gas cylinder 1408, the gas flow rate controller 1409, and the valve 1416 is at the ground potential, and is insulated from the ionization chamber by an insulating pipe 1417 downstream from the valve 1416.
The processing chamber is provided with an RF electron gun 1418 for preventing charging of the sample.
Then, Ar gas adjusted to an arbitrary flow rate is introduced from the gas cylinder 1408 via the gas flow rate controller 1419 into the ionization chamber 1421 of the electron gun via the metal pipe 1425 and the insulating flange 1420.

In the ionization chamber 1421, plasma is generated when an RF wave of 13.56 MHz is incident at a gas pressure of about 10 Pa, and electrons are extracted therefrom and irradiated on the sample 1411.
Further, the RF electron gun 1418 is set to a high potential of 200 V to 5 kV by the acceleration power source 1423 connected through the feedthrough 1422, so that the RF electron gun 1418 is insulated from the processing chamber 1406 by the insulating flange 1420.
As shown in FIG. 14 (b), the insulating pipe 1417 includes three insulating pipes 1426, 1427, and 1428 that are adjacent to each other by using three 1mm-thick metal plates 1429 having a half-moon shaped opening. The flow paths are connected so as not to be straight.
The insulator 1430 is cylindrical alumina, and has an outer diameter of 120 mm, an inner diameter of 100 mm, and a length of 30 mm.
The porous conductive plate 1431 is a stainless plate having an outer diameter of φ99 mm having a plurality of openings with a thickness of 0.5 mm, a hole diameter of φ0.5 mm, and a pitch of 1 mm, and the distance between the conductive plates is all 1 mm.
The porous conductive plate 1431 is electrically connected to the metal flanges 1432, 1433, 1434, and 1435, respectively.
Further, all the porous conductive plates 1431 are subjected to an electric field polishing treatment so that electron field emission does not occur.

Further, as shown in FIG. 14C, in the insulating flange 1420, a stepped process is applied to the inner surface of an insulator 1436 made of alumina whose volume resistivity is adjusted to about 10 ⁹ Ω · cm. Has been.
Ten porous conductive plates 1437 are provided at intervals of 0.5 mm in each step.
The porous conductive plates at both ends are electrically connected to the metal flanges 1438 and 1439, respectively.
As shown in FIG. 14D, the porous conductive plate 1437 is formed by arranging arc-shaped holes 1441 having a width of 3 mm on a stainless steel plate having a thickness of 0.5 mm and an outer diameter of 40 mm to 50 mm at a pitch of 9 mm.
And it is designed so that the radius of the arc-shaped hole of adjacent porous conductive plates may be shifted by 4.5 mm.
All the porous conductive plates 1437 are subjected to an electric field polishing treatment so that electron field emission does not occur.
When a withstand voltage test was performed using this apparatus in an actual use state, no discharge occurred in the insulating pipe 1417 and the insulating flange 1420.

[Example 3]
In Example 3, an ion implantation apparatus configured by applying an insulating pipe having a different form from the above-described examples will be described.
FIG. 15 is a diagram illustrating the configuration of the ion implantation apparatus according to this embodiment.
FIG. 15A is a diagram showing an outline of an ion implantation apparatus using a capacitively coupled plasma system as an ion source.
FIG. 15B is a cross-sectional view showing an outline of the insulating piping used in this embodiment, and FIG. 15C is a diagram for explaining the configuration of the porous conductive plate.

As shown in FIG. 15A, the ion implantation apparatus of the present embodiment is configured by using a capacitively coupled plasma system as an ion source.
An ionization chamber 1501 and a high frequency flange portion 1503 attached to the ionization chamber 1501 via an insulator 1502 are connected to a high frequency power source 1504.
The ionization chamber 1501 and the processing chamber 1505 are evacuated by an exhaust device 1506.
At the same time, a raw material gas adjusted to an arbitrary flow rate from a gas cylinder 1507 via a gas flow rate controller 1508 is introduced into the ionization chamber 1501 through a metal pipe 1509.
There are five kinds of source gases used: PH ₃ , AsH ₃ , NH ₃ , Ar, and O ₂ .
The pressure in the ionization chamber 1501 during operation is about 0.8 Pa to 9.4 Pa.

Further, a high voltage of 10 kV to 150 kV is applied between the processing chamber 1505 and the ionization chamber 1501 at the ground potential by the acceleration power supply 1510.
The ion beam 1513 is extracted from the plasma 1511 generated in the plasma chamber 1501 by the high frequency application by the extraction conductive plate 1512 and focused by the focusing lens 1514, and then only desired ions are selected by the mass separator 1515.
The selected ions are irradiated to a desired region on the sample 1518 by the focusing lens 1516 and the deflection lens 1517.
The gas introduction system such as the gas cylinder 1507, the gas flow rate controller 1508, and the valve 1519 is at the ground potential, and is insulated from the ionization chamber by the insulating pipe 1520 downstream from the valve 1519.

A more detailed schematic diagram of the insulating pipe 1520 is shown in FIG.
In this insulating pipe 1520, three insulators 1521, 1522, 1523 made of alumina whose volume resistivity is adjusted to about 10 ⁹ Ω · cm are connected via metal flanges 1524, 1525, 1526, 1527. Has been.
Inside each of these metal flanges, three metal plates 1528 each having a half-moon shaped opening are provided so that the internal flow paths of adjacent insulating pipes do not become straight. Further, the inner surfaces of the insulators 1521, 1522, and 1523 are stepped, and a porous conductive plate 1529 is arranged on each step.
The porous conductive plates at both ends are electrically connected to metal flanges 1524, 1525, 1526, and 1527, respectively.
In addition, a total of 60 porous conductive plates 1529 are provided in a single insulator, 20 sheets at intervals of 0.5 mm.

As shown in FIG. 15 (c), the porous conductive plate 1529 of this example has a thickness of 0.5 mm having opposing fan-shaped holes 1531 and an outer diameter of 181 mm to 200 mm, and the opening positions of adjacent porous conductive plates are They are arranged 90 degrees apart so as not to match.
Further, all the porous conductive plates 1529 are subjected to electropolishing.
Further, in order to prevent charging of the porous conductive plate and the metal flange, the metal flanges 1524, 1525, 1526, and 1527 are connected by a resistor 1530 of 1000Ω.
When this apparatus was used and a withstand voltage test was performed in the range of 10 to 150 kV in an actual use state, no discharge occurred in the insulating pipe 1520.

It is a figure explaining the ion milling apparatus in Example 1 of this invention, (a) is a figure which shows the outline of the ion milling apparatus which used the ECR plasma system for the ion source, (b) is the insulation used for a present Example. The figure which shows the outline of piping. The figure explaining the plasma processing apparatus in the conventional gas cylinder high potential system. The figure explaining the plasma processing apparatus in the conventional gas cylinder grounding potential system. The conceptual diagram for demonstrating Paschen's law. It is a figure explaining the electric field in an insulated pipe, (a) is a figure explaining the electric field in the conventional insulated pipe, (b) is the electric field in the insulated pipe using the porous conductive plate in embodiment of this invention. FIG. The figure which shows the structure of the insulation piping in the 1st Embodiment of this invention. The figure which shows the data of the withstand voltage test in the insulated piping of the 1st Embodiment of this invention. The figure which shows the structure of the multistage insulation piping in the 2nd Embodiment of this invention. The figure which shows the data of the withstand voltage test in the multistage insulated piping of the 2nd Embodiment of this invention. The figure which shows the structure of the multistage insulation piping in the 2nd Embodiment of this invention. The figure which shows the structure of the insulation flange in the 3rd Embodiment of this invention. It is a figure explaining the positional relationship of the hole in the porous conductive plate of the 3rd Embodiment of this invention, (a) is a figure explaining the case where the position of a hole corresponds, (b) is the position of a hole. The figure explaining the case where it shifted. The figure which shows the data of the withstand voltage test of the insulation piping which comprises a multistage porous conductive plate. It is a figure explaining the ion milling apparatus in Example 2 of this invention. (A) is a figure which shows the outline of the ion milling apparatus which used the ECR plasma system for the ion source, (b) is sectional drawing which shows the outline of the insulated piping, (c) is sectional drawing which shows the outline of an insulating flange, d) is a plan view thereof. It is a figure explaining the structure of the ion implantation apparatus in Example 3 of this invention. (A) is a figure which shows the outline of the ion implantation apparatus which used the capacitive coupling plasma system for the ion source, (b) is sectional drawing which shows the outline of insulation piping, (c) is a figure explaining the structure of the porous conductive plate. .

Explanation of symbols

117, 1417, 1520: Insulation piping 118, 601, 1101, 1430, 1436, 1521, 1522, 1523: Insulator 121, 604, 1104, 1431, 1437, 1529: Porous conductive plates 801, 1429, 1528: Conductive plates ( Metal plate)
1001: bent pipe 1420: insulation flange

Claims (4)

Insulated piping in which both ends of the tube are electrically insulated,
Metal flanges with openings, spaced apart;
An insulator disposed between the metal flanges arranged at intervals, and
In the space formed by the metal flange and the insulator,
Dividing the metal plate having a half-moon shaped opening so that the internal flow path does not become a straight line by arranging a plurality of the openings so that the openings are at different positions,
In the divided space, having said metal flange with a plurality of openings which are conductive, at intervals discharge under pressure does not occur in the insulation pipe, and the porous conductive plate arranged to overlap a plurality of sheets,
Insulating piping characterized by having. The insulating pipe according to claim 1, wherein a spacer is disposed between the porous conductive plates. An ionization chamber, and a gas introduction system for introducing a raw material gas into the ionization chamber,
A plasma processing apparatus comprising the insulating pipe according to claim 1 or 2 , wherein the ionization chamber is insulated from the gas introduction system. In a plasma processing method comprising an ionization chamber and a gas introduction system, introducing a source gas from the gas introduction system into the ionization chamber, and processing a sample with plasma generated in the ionization chamber,
Insulating between the ionization chamber and the gas introduction system by an insulating pipe, and when introducing the source gas into the ionization chamber through the insulating pipe,
As the insulating pipe, metal flanges having openings arranged at intervals, and
An insulator disposed between the metal flanges arranged at intervals, and
In the space formed by the metal flange and the insulator,
Dividing the metal plate having a half-moon shaped opening so that the internal flow path does not become a straight line by arranging a plurality of the openings so that the openings are at different positions,
In the divided space, having said metal flange with a plurality of openings which are conductive, at intervals discharge under pressure does not occur in the insulation pipe, and the porous conductive plate arranged to overlap a plurality of sheets,
The plasma processing method characterized by using the insulation piping which has this.

Images