JP2000030893A - Plasma generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate plasma in a large area, to clarify the plasma boundary end face and to allow the position selection of a process material such as a substrate in a plasma generator exciting the wave motion of the helicon wave or slow wave propagating along the external magnetic field shown by the magnetic lines of force on the antenna side with an antenna. SOLUTION: The second external magnetic field shown by the magnetic lines of force 10 of a magnetic field generating coil 8 on a vacuum container side is provided at a position apart from an antenna 3, and the magnetic lines of force 9 on the antenna side and the magnetic lines of force 10 on the vacuum container side are made opposite to each other in direction to form the cusp field. The magnetic lines of force 9 exist to a large radius at the boundary between both external magnetic fields formed by the opposing magnetic lines of force 9, 10, plasma is generated in a large area, and the plasma boundary end face can be clarified. Since the plasma boundary end face is made clear, a process material 11 such as a large-diameter substrate can be installed via position selection according to the aimed process on the inside or outside of the plasma end face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma generating apparatus useful for process processing using plasma, such as film formation and etching.

[0002]

2. Description of the Related Art As a plasma generation method, a method of generating plasma by a helicon wave, which is an electromagnetic wave propagating along the magnetic field lines of an external magnetic field, has been disclosed in 1970 (RWB).
oswell: Phys. Lett. 33A, (1970) 457) and is known.

In order to process a large-diameter material, one method of increasing the plasma diameter is as follows.
A method using a vacuum vessel-side magnetic field generation coil, which has a larger diameter than the antenna-side magnetic field generation coil, was described in the paper (AJPe
rry and RWBoswell: Appl. Phys. Lett. 55 (1989) 148) and known.

FIG. 7 shows an example of a conceptual configuration of a conventional apparatus devised to increase the diameter of the helicon wave plasma.

In FIG. 7, a cylindrical vacuum vessel 16 having a larger diameter is connected to a dielectric tube 1 such as a glass tube or the like, and the two tubes 1 and 16 have a common inner space and a common central axis. It is configured. A loop-shaped antenna 3 is provided on the outer periphery of the dielectric tube 1, and the antenna 3 is connected to a high-frequency power supply 5 via a matching unit 4. Outside the dielectric tube 1, a plurality of solenoid-shaped antenna-side magnetic field generating coils 7 are further provided. Outside the vacuum vessel 16, a plurality of solenoid-shaped vacuum vessel-side magnetic field generating coils 8 having a larger diameter than the antenna-side magnetic field generating coil 7 are provided.

In such a plasma generator, first,
The dielectric tube 1 and the vacuum vessel 16 are filled with a gas according to the process at a pressure according to the purpose. Next, current is supplied to the antenna-side magnetic field generating coil 7 and the vacuum vessel-side magnetic field generating coil 8. At this time, near the antenna 3, uniform antenna-side magnetic lines of force 9 are formed in the axial direction of the device, and the
Inside, the vacuum vessel side magnetic field lines 10 are formed, and the current flowing through both coils 7 and 8 is adjusted so that the magnetic field lines are continuously spread from the antenna 3 side to the vacuum vessel 16 side. The directions of the magnetic field lines 9 on the antenna side and the magnetic field lines 10 on the vacuum vessel side are shown in FIG.
Although it may be rightward or leftward in the middle, the directions are the same. Next, high frequency power is applied to the antenna 3 from the high frequency power supply 5 via the matching unit 4.

By the above operation, a helicon wave is excited from the antenna 3 along the magnetic lines of force 9 and 10, and a plasma 6 is generated in a region where the wave propagates.

The plasma 6 hardly spreads in the radial direction across the lines of magnetic force 9 and the lines of magnetic force 10, and usually does not reach the inner wall of the dielectric tube 1 and the vacuum vessel 16. On the other hand, in the direction of the line of magnetic force, from the end of the dielectric tube 1 on the opposite side to the vacuum vessel 16,
The plasma 6 spreads into the vacuum chamber 16. Plasma 6
Spread in the direction of the magnetic field depends on the type of gas to be filled and the pressure. The larger the pressure, the smaller the spread.

At an appropriately low gas pressure, the lines of magnetic force 9
Since the magnetic lines of force slightly extend in the direction of a large radius in the region between the magnetic field lines 10 and 10, the diameter of the plasma 6 in the vacuum vessel 16 increases as shown in the figure.

The processing material 11 such as a substrate is placed at an appropriate position on the axis in the vacuum chamber 16 where the plasma 6 is generated, so that the processing surface is perpendicular to the axis of the apparatus. A process using plasma 6 such as etching is performed.

[0011]

The above-described conventional plasma generator has the following three problems.

First problem: The maximum diameter of the plasma 6 is smaller than the inner diameter of the vacuum vessel side magnetic field generating coil 8. Therefore, when the diameter of the vacuum vessel 16 and the vacuum vessel-side magnetic field generating coil 8 is increased in order to increase the diameter of the plasma 6, the power required for generating the magnetic field increases in proportion to the square of the diameter of the coil 8, and the economy increases. The performance and compactness are reduced.

Second problem: The spread of the plasma 6 cannot be restricted in the direction of the line of magnetic force. Therefore, even when the processing material 11 such as a substrate to be processed is not desired to be directly exposed to the plasma 6, the processing material 11 must be installed in the plasma 6. That is, in the plasma 6, the charged particles obtain energy from the wave to decompose the raw material gas to generate active neutral atoms and molecules, and the process is performed using the active neutral atoms and molecules. On the other hand, charged particles having energy are often harmful. Therefore, when it is necessary not to be directly exposed to the plasma 6, other means such as applying a voltage for suppressing the flow of the plasma into the processing material 11 are necessary, but often insufficient.

Third problem: coil 8 for generating a magnetic field on the vacuum vessel side
In the plasma 6 having a large diameter by increasing the diameter, the density decreases as the distance increases in the radial direction. Therefore, when the processing material 11 is a large substrate or the like, the processing speed differs between the center and the periphery on the surface of the processing material 11, and uniform processing cannot be performed. This is because the electric field of the wave excited by the antenna 3 is weak at a place where the radius is large, and therefore, the density of the plasma generated by the wave is reduced at a place where the radius is large.

[0015]

According to a first aspect of the present invention, there is provided a plasma generating apparatus for solving the above-mentioned problems, wherein a plasma for exciting a wave such as a helicon wave or a slow wave propagating along a magnetic field line of an external magnetic field with an antenna. In the generator, two kinds of external magnetic field generating means for adding a second magnetic field different from the antenna-side magnetic field to form a cusp magnetic field (a magnetic field line arrangement in which two external magnetic field lines are opposite to each other) are formed. It is characterized by having.

According to a second aspect of the present invention, there is provided a plasma generating apparatus comprising a magnetic field intensity adjusting means for relatively adjusting the intensities of two kinds of external magnetic fields generated by the two kinds of external magnetic field generating means. Device.

According to a third aspect of the present invention, there is provided a plasma generator comprising a high-frequency power injection electrode provided near a boundary between two cusp magnetic fields.

The invention according to claim 4 is characterized in that, in the generation of the two types of external magnetic fields, the same effect can be obtained by introducing a cusp magnetic field even if the antenna-side magnetic field strength distribution is uniform or changes. Is a plasma generator.

The invention according to claim 5 is a plasma generator characterized in that at least one of the two types of external magnetic field generating means is one of an electromagnetic coil and a permanent magnet.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described with reference to FIGS. FIG. 1 shows a configuration of a plasma generator according to a first embodiment of the present invention. FIG. 2 shows a configuration of a plasma generator according to a second embodiment of the present invention,
3 shows the radial dependence of the electron density in the second embodiment, FIG. 4 shows the coil current dependence of the electron density in the second embodiment, and FIG. 5 shows the axial dependence of the electron density in the second embodiment. Is shown. FIG. 6 shows a configuration of a plasma generator according to a third embodiment of the present invention.

[First Embodiment] The plasma generating apparatus shown in FIG. 1 uses a cusp magnetic field based on the present invention in a device configuration in which the antenna side magnetic field intensity distribution, which is most frequently used as helicon wave plasma, is uniform. It is added.

In FIG. 1, a dielectric tube 1 such as a glass tube is shown.
Is connected to a cylindrical vacuum vessel 2 having a portion larger in diameter than the conventional vacuum vessel 16 so that the dielectric tube 1 and the vacuum vessel 2 have a common inner space and a common central axis. It is configured. A loop-shaped antenna 3 is provided on the outer periphery of the dielectric tube 1.
Is installed, and the antenna 3 is connected to the high-frequency power supply 5 via the matching unit 4. When a uniform magnetic field in the axial direction is formed by the antenna-side magnetic field generating coil 7 and the antenna 3 is installed at a central position on this axis, the helicon wave propagates to both sides on the axis but propagates to the vacuum vessel side. Use only one wave.

That is, two antenna-side magnetic field generating coils 7 are arranged coaxially on both sides of the antenna 3, and two antenna-side magnetic field generating coils 7 immediately adjacent to the antenna 3 are located on the outer periphery of the dielectric tube 1. One of the two antenna-side magnetic field generating coils 7 far from the antenna 3 is located farther than the end of the dielectric tube 1 on the side opposite to the vacuum vessel, and the other is a dielectric tube larger than the large-diameter portion of the vacuum vessel 2. Located on the outer circumference of the side. The vacuum container-side magnetic field generating coil 8 has the same diameter as the antenna-side magnetic field generating coil 7, and is arranged on the outer periphery of the vacuum container 2 closer to the anti-dielectric tube than the large diameter portion. The current flowing through the antenna-side magnetic field generating coil 7 and the vacuum vessel-side magnetic field generating coil 8 is converted into the magnetic field lines 10 generated by the vacuum vessel-side magnetic field generating coil 8 by the magnetic field lines 9 generated by the antenna-side magnetic field generating coil 7. Is set to be in the direction opposite to.

Assuming that the magnetic line of force 10 generated by the coil 8 for generating a magnetic field on the vacuum vessel side is in the direction opposite to the magnetic line of magnetic force 9 on the antenna side, as shown in FIG. A cusp magnetic field (a magnetic field line arrangement in which the directions of the magnetic field lines of the two magnetic fields are opposite to each other) is formed, and the magnetic field lines 9 and 10 exist over a large radius.
The large-diameter portion of the vacuum vessel 2 is located in this area.

By adopting such a cusp magnetic field, the direction of the magnetic force lines 9 and 10 can be bent from the axial direction to the radial direction, and the magnetic force lines 9 and 10 can be expanded to a place having a larger radius than the magnetic field generating coils 7 and 8. The large-diameter plasma 6 can be generated by guiding the wave and the plasma in the radial direction. That is, the plasma 6 is generated in a shape having an area larger than or equal to the diameter of the coils 7 and 8. Moreover, since the waves and plasma do not spread across the magnetic lines of force 9, 10,
The plasma 6 is generated only on the magnetic line 9 on the antenna side, and does not spread on the magnetic line 10 on the vacuum vessel side, which is different from the magnetic line 9 on the antenna side, and the boundary between them becomes a sharp plasma boundary. . However, in the case of a plasma having a high gas pressure, the effect of collision between particles is superior, and a phenomenon of scattering from this boundary surface is also observed.

As described above, in the plasma generator in which the high frequency antenna 3 excites the wave such as the helicon wave or the slow wave propagating along the external magnetic field indicated by the magnetic field line 9 on the antenna side, the vacuum vessel is located at a position away from the antenna 3. The second external magnetic field indicated by the magnetic field lines 10 is provided by the side magnetic field generating coil 8, and the directions of the magnetic field lines 9, 10 of the two magnetic fields are reversed to form a cusp magnetic field. In this case, the magnetic lines of magnetic force 9 on the antenna side exist up to a large radius, and the area of the plasma 6 can be increased and the end face of the plasma boundary can be clarified. In addition, a processing material 11 such as a large-diameter substrate can be selected and installed on the inside and outside of the end face of the plasma 6 according to a target process. Further, the device can be operated with the smaller-diameter magnetic field generating coils 7 and 8 for a plasma having the same large diameter, which is more compact than the conventional device,
The capacity of these coil power supplies is also small, which is economical.

[Second Embodiment] In the plasma generating apparatus shown in FIG. 2, the antenna-side magnetic field generating coil 7 is arranged on only one side of the antenna 3, and the magnetic field intensity distribution changes at the position of the antenna 3. A cusp magnetic field is added to the device.

FIG. 2 also shows a dielectric tube 1 such as a glass tube.
Is connected to a cylindrical vacuum vessel 2 having a portion having a larger diameter than the conventional vacuum vessel 16. Both of them have a common internal space and a common central axis. . A loop-shaped antenna 3 is installed on the outer periphery of the dielectric tube 1,
The antenna 3 is connected to a high frequency power supply 5 via a matching unit 4. The two antenna-side magnetic field generating coils 7 are arranged coaxially on the vacuum vessel side of the antenna 3, and the antenna-side magnetic field generating coil 7 immediately adjacent to the antenna 3 is located on the outer periphery of the dielectric tube 1. The antenna-side magnetic field generating coil 7 that is farther from the outside is located closer to the dielectric tube side than the large-diameter portion of the vacuum vessel 2. The vacuum container-side magnetic field generating coil 8 has the same diameter as the antenna-side magnetic field generating coil 7, and is arranged on the outer periphery of the vacuum container 2 closer to the anti-dielectric tube than the large-diameter portion.

The current flowing through the antenna-side magnetic field generating coil 7 and the vacuum container-side magnetic field generating coil 8 is generated by the magnetic field lines 10 generated by the vacuum container-side magnetic field generating coil 8 by the antenna-side magnetic field generating coil 7. It is set so as to be in the direction facing the magnetic force line 9.

Therefore, in FIG. 2, the plasma emission is weak on the side of the antenna 3 where the antenna-side magnetic field generating coil 7 is not provided, and the plasma 6 does not reach the end of the dielectric tube 1.

Further, in this example, the magnetic field strength adjusting means 12
Is provided. Specifically, by adjusting the current flowing through the antenna-side magnetic field generating coil 7 and the current flowing through the vacuum vessel-side magnetic field generating coil 8 by the magnetic field strength adjusting means 12, the external current generated by the antenna-side magnetic field generating coil 7 is adjusted. The intensity ratio between the magnetic field and the external magnetic field formed by the vacuum vessel side magnetic field generating coil 8 can be changed.

FIG. 3 shows the result of measuring the distribution of the electron density in the radial direction at a position 300 mm away from the antenna 3 toward the vacuum vessel in the example shown in FIG.

In FIG. 3, when the coil 8 for generating a magnetic field on the vacuum vessel side has the same magnetic field direction as the coil 7 for generating a magnetic field on the antenna as in the prior art, a typical magnetic field strength of 550 Ga
In high frequency power injection of uss, hydrogen gas of 30 mTorr, and 2 KW of 27 MHz, the electron density is 3 × 10 ¹² cm ⁻³ and the plasma diameter is almost the same as the diameter of the antenna 3 of 50 mm.

On the other hand, in the case of a cusp magnetic field in which the external magnetic field generated by the vacuum container side magnetic field generating coil 8 is in the opposite direction to the external magnetic field generated by the antenna magnetic field generating coil 7 (maximum magnetic field strength on the axis ± 550 Gauss), 2 × 10 ¹¹ cm ^-3 up to a diameter of 120 mm determined by the conditions of the equipment used, such as the aperture of 2.
The electron density of was observed. If a vacuum vessel having a larger diameter is used, the plasma diameter can be expected to increase, although the density tends to decrease.

Next, FIG. 4 shows a comparison between the case where the current values of the antenna side magnetic field generating coil 7 and the vacuum vessel side magnetic field generating coil 8 for forming the cusp magnetic field are changed and the case where the current values are the same. Thus, the dependence of the electron density on the coil current ratio is shown. The antenna, high-frequency power conditions, and gas conditions are the same as those in FIG. 3. However, if the value of the current flowing through the vacuum vessel-side magnetic field generating coil 8 is slightly reduced, the electron density at a radius of ± 30 mm becomes larger than the center. Thus, the radial distribution of the electron density could be made uniform.

FIG. 5 shows the electron density in the device axis direction (Z-axis distance) when the two external magnetic fields generated by the antenna-side magnetic field generating coil 7 and the vacuum vessel-side magnetic field generating coil 8 are in the same direction. The distribution and the distribution of the electron density in the device axis direction (Z-axis distance) in the case of a cusp magnetic field are shown in comparison. In FIG. 5, the ion saturation current, which is a measured value, is directly shown because the change in the electron temperature is not corrected. However, since the change in the electron temperature is as small as 4 to 7 eV, the value of the ion saturation current substantially shows the electron density distribution. This is clear from texts such as plasma physics.

According to FIG. 5, the boundary of the cusp magnetic field is the antenna 3
From the center of the plasma 6 (Z = 300 mm), at which position the electron density of the plasma 6 sharply decreases. With respect to the plasma emission intensity observed with the naked eye, strong emission is seen on the antenna side from this boundary surface, but almost no emission is seen on the opposite side. Therefore, it is possible to select an appropriate position by moving the processing material 11 such as the substrate away from or close to the large-diameter plasma 6.

As described above, in the plasma generator that excites the waves such as the helicon wave and the slow wave propagating along the external magnetic field indicated by the magnetic field lines 9 on the antenna side with the high-frequency antenna 3, the antenna-side magnetic field generating the cusp magnetic field is generated. By changing the intensity ratio between the external magnetic field generated by the coil 7 for use and the external magnetic field generated by the coil 8 for generating a magnetic field on the vacuum vessel side, the plasma 6
, The spatial position of the plasma end face in the axial direction, and the plasma distribution density can be adjusted. Therefore, even when the processing material 11 such as a substrate is fixed in the vacuum vessel 2, the relative position with respect to the plasma 6 can be changed as necessary by changing the intensity ratio between the two external magnetic fields.

[Third Embodiment] In the plasma generator shown in FIG. 6, a ring-shaped electrode 13 is added as a high-frequency injection electrode at a position where the radius of the cusp magnetic field is large in the example of FIG.
The second matching unit 14 and the second high-frequency power supply 15 inject high-frequency power from the ring-shaped electrode 13 to additionally generate plasma in a region where the radius of the plasma 6 is large.
In this case, since the shape of the plasma 6 is generally a disk shape having a large diameter, the power injection method matching this shape is such that the inductive coupling of the antenna 3 or the like has a large impedance, so that two thin rings having a small impedance are used. The capacitive coupling method using the ring-shaped electrode 13 is adopted, and the ring-shaped electrode 13 is arranged in a region larger than the radius of the cusp magnetic field to additionally inject high-frequency power.

In the example of FIG. 2, the electron density was reduced when the diameter was 80 mm or more in both the results of FIGS. 3 and 4.
The plasma density can be made uniform up to a larger diameter.

As described above, in the plasma generating apparatus in which the high frequency antenna 3 excites the waves such as the helicon wave and the slow wave propagating along the external magnetic field indicated by the magnetic line 9 on the antenna side, the coil 8 for generating the magnetic field on the vacuum vessel side. Magnetic field lines 10
Are provided, and the lines of magnetic force 9, 10 of both magnetic fields are provided.
Is reversed to form a cusp magnetic field, and a high-frequency power injection electrode 13 is added to a region having a large radius where two opposing magnetic lines of force 9 and 10 of the cusp magnetic field are in the same direction to additionally inject high-frequency power. Thereby, the peripheral density of the plasma 6 having a large area is improved, and the plasma density can be made uniform.

In each of the above embodiments, two types of external magnetic fields are both generated by using an electromagnetic coil. However, both external magnetic fields may be generated by using a permanent magnet, or one of the external magnetic fields may be generated. May be generated using an electromagnetic coil, and the other external magnetic field may be generated using a permanent magnet.

When two external magnetic fields are generated using only permanent magnets, the intensity ratio between the two external magnetic fields can be changed by appropriately using an electromagnetic shield or the like.

Further, the waves propagating along the lines of magnetic force include not only helicon waves but also other waves such as slow waves, and whether the magnetic field intensity distribution is uniform or changes in the area of the antenna.
The invention is equally applicable to different types of plasma generation methods.

That is, in the third embodiment shown in FIG. 6, a cusp magnetic field is formed in a plasma generator in which a magnetic field intensity distribution changes in a region of the high-frequency antenna 3 which excites a wave propagating along the magnetic force lines 9. A ring-shaped electrode 13 is provided near the boundary between two cusp magnetic fields as a high-frequency injection electrode.
, But is not limited to this.

For example, as shown in FIG. 1, a cusp magnetic field is formed in a plasma generator in which the magnetic field intensity distribution is uniform in a region of the high-frequency antenna 3 that excites a wave propagating along the magnetic field lines 9; By adding a high-frequency injection electrode such as a ring-shaped electrode 13 near the boundary of the cusp magnetic field as shown in FIG. 6, the peripheral density of the large-area plasma 6 is improved, and the plasma density is made uniform. It becomes possible.

[0047]

According to the plasma generator of the present invention, the following effects can be obtained.

According to the first aspect of the present invention, there is provided a plasma generator which excites a wave such as a helicon wave or a slow wave propagating along a magnetic field line of an external magnetic field with an antenna. Since two types of external magnetic field generating means are provided to form a cusp magnetic field (magnetic field lines of two external magnetic fields in which the directions of the magnetic field lines are opposite to each other) by applying a magnetic field, an electromagnetic coil or the like for forming a cusp magnetic field is provided. The lines of magnetic force are largely spread in the radial direction between the two types of magnetic field generating means, and the plasma is spread along the lines of magnetic force, so that a large area plasma such as a coil diameter can be formed. Therefore, an economical and compact plasma generator can be obtained.

Further, between the two types of magnetic field generating means for forming the cusp magnetic field, the magnetic field lines are directed in the radial direction perpendicular to the central axis of the apparatus, and the plasma does not spread across the magnetic field lines. As a result, a sharp plasma boundary is formed on the surface facing the cusp magnetic field. Therefore, if a processing material such as a substrate is placed on the opposite side of this boundary from the antenna, it will not be directly exposed to the plasma, but since it is close to the plasma, active neutral atoms and molecules will reach the processing material. Desired treatment can be performed without being exposed to charged particles that have harmful energy.

According to the second aspect of the present invention, since the magnetic field intensity adjusting means for relatively adjusting the intensities of the two types of external magnetic fields generated by the two types of external magnetic field generating means is provided, the processing of a substrate or the like is performed. Even if the position of the material is fixed, the position of the plasma can be adjusted, and conditions can be changed, such as exposing or not exposing to plasma.

According to the third aspect of the present invention, since the high frequency power injection electrode provided near the boundary between the two cusp magnetic fields is provided, the plasma generating apparatus is provided at a position having a large radius where the plasma density tends to decrease. In addition, plasma is generated by high frequency power injection from the electrode to compensate for the shortage, and the plasma density in the peripheral portion is increased to make the plasma density uniform.
Therefore, plasma processing can be performed even with a large processing material.

According to the fourth aspect of the present invention, in the two external magnetic fields, the antenna-side magnetic field strength distribution is the same as the apparatus most frequently used as the helicon wave plasma having the uniform antenna-side magnetic field strength distribution. Even if it changes, there is the same effect as above.

According to the fifth aspect of the present invention, at least one of the two types of external magnetic field generating means may be any one of an electromagnetic coil and a permanent magnet.
Even when the magnetic field generating means uses not only an electromagnetic coil but also a permanent magnet, the same effect as described above can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a plasma generator according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a plasma generator according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a radius dependence of an electron density in a second embodiment of the present invention.

FIG. 4 is a diagram showing coil current dependence of electron density in a second embodiment of the present invention.

FIG. 5 is a diagram showing the dependence of electron density on the axial direction in a second embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a plasma generator according to a third embodiment of the present invention.

FIG. 7 is a schematic configuration diagram showing an example of a conventional plasma generator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dielectric tube 2 Vacuum container 3 Antenna 4 Matching device 5 High frequency power supply 6 Plasma 7 Antenna side magnetic field generating coil 8 Vacuum container side magnetic field generating coil 9 Antenna side magnetic field line 10 Vacuum container side magnetic field line 11 Processing material 12 Magnetic field strength ratio adjusting means 13 ring-shaped electrode 14 second matching device 15 second high frequency power supply

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuya Ikeda 1-8-1 Koura, Kanazawa-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsubishi Heavy Industries, Ltd. 8-1 Inside Mitsubishi Heavy Industries, Ltd. Fundamental Technology Laboratory

Claims (5)

[Claims] 1. A plasma generator that excites a wave such as a helicon wave or a slow wave propagating along a magnetic field line of an external magnetic field with an antenna by adding a second magnetic field different from an antenna-side magnetic field to two external magnetic fields. Of magnetic field lines in opposite directions (hereinafter referred to as cusp magnetic field)
Characterized in that it comprises two types of external magnetic field generating means for forming a magnetic field. 2. The plasma generating apparatus according to claim 1, further comprising magnetic field intensity adjusting means for relatively adjusting the intensities of the two types of external magnetic fields generated by said two types of external magnetic field generating means. 3. The plasma generator according to claim 1, further comprising a high-frequency power injection electrode provided near a boundary between the two cusp magnetic fields. 4. The method according to claim 1, wherein, in the generation of the two types of external magnetic fields, the magnetic field intensity distribution at the antenna setting position is one of uniform distributions. Plasma generator. 5. The plasma generator according to claim 1, wherein at least one of the two types of external magnetic field generating means is one of an electromagnetic coil and a permanent magnet.