JP2003197115A - Ion source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion source device capable of generating ion beam under clean environment by preventing the device from being contaminated by an RF antenna. <P>SOLUTION: This ion source device S comprises a discharge means 3 for discharging, a discharge chamber 1 having an opening 12 and holding plasma generated by discharging, and an extraction electrode 6 for extracting ion beam from plasma by closing the opening 12 of a discharge chamber 1. The discharge means 3 is disposed on the outside of a side face 13 adjacent to the face of the discharge chamber 1 having the opening 12. The discharge chamber 1 is formed of an insulator. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion source device, and more particularly to an ion source device having a simple structure and high ion extraction efficiency.

[0002]

2. Description of the Related Art In the field of semiconductors, a technique of using an ion source device is used in processes such as etching and thin film formation in the process of manufacturing semiconductor devices. For example, as dry etching using an ion source device, plasma is generated using an inert gas in the ion source device held in an electrostatic state, and inert gas ions are extracted from this plasma to irradiate the wafer and perform etching. A technique called "ion beam etching" is known. In addition, as a thin film formation using an ion source device, the metal vapor evaporated from the metal evaporation source and the ion beam extracted from the ion source device are simultaneously supplied to the substrate to form a thin film while changing the properties of the thin film. A technique called "assisted vapor deposition" is known.

As an ion source device used in these techniques, Japanese Patent Application Laid-Open No. 2001-210245 proposes an ion source device shown in FIG. The ion source device shown in FIG. 6 has a discharge chamber 101, a gas inlet 102 for introducing gas, an RF antenna 103 for discharging, and a plurality of magnets 105 arranged near the inner wall surface of the discharge chamber 101.
And the ion extraction electrode 106 provided so as to close the discharge chamber 101 are the main constituent elements. Then, as shown in FIG. 7, a plurality of vertically long magnets 105 are arranged along the inner wall of the discharge chamber 101 such that the magnetic pole surfaces of the N pole and the S pole are alternately inverted. In this ion source device,
Argon gas, oxygen gas, and the like are introduced into the pressure-reduced discharge chamber 101, plasma is generated by discharging with the RF antenna 103, and ions are extracted from the plasma with the ion extracting electrode 106 to generate an ion beam.

According to the ion source device shown in FIG. 6, since the cusp magnetic field is generated by the magnet 105 surrounding the interior of the discharge chamber 101, high density plasma can be obtained and high ion extraction efficiency can be obtained. Is possible.

However, in the ion source device having such a structure, the RF antenna 10 which is a conductor is provided in the discharge chamber 101.
Since 3 is arranged, R is generated when plasma is generated.
The F antenna 103 is sputtered and R
There is a problem that the F antenna 103 materials are mixed and cause contamination. Therefore, there is a problem that the metal film derived from the RF antenna 103 adheres to the inner wall of the discharge chamber 101 and cannot be continuously used for a long time. Further, since the magnets 105 used under high temperature are arranged as shown in FIG. 6, it is necessary to provide a water cooling mechanism to prevent demagnetization of the magnets 105, and the structure inside the discharge chamber 101 becomes complicated. There was a point.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide an ion source device capable of generating an ion beam in a clean environment by preventing contamination by an RF antenna. Especially. Another object of the present invention is to provide an ion source device which can prevent contamination by an RF antenna and can be stably used continuously for a long time.

[0007]

According to the invention as defined in claim 1, the above-mentioned object is to provide a discharging means for discharging, a discharge chamber having an opening for holding plasma generated by the discharge, An extraction source for closing the opening of the discharge chamber and extracting an ion beam from the plasma, wherein the discharge means is a side surface adjacent to a surface having the opening of the discharge chamber. This is solved by arranging on the outside and the discharge chamber consists of an insulator.

As described above, since the discharge means is arranged outside the side surface adjacent to the surface having the opening of the discharge chamber, the discharge means such as the RF coil antenna is sputtered during the operation of the ion source device. As a result, it is possible to prevent the occurrence of contamination and to supply the ion beam in a clean environment. Further, the metal film derived from the discharge means is prevented from adhering to the inner wall of the discharge chamber, and the R of the inner wall of the discharge chamber is prevented.
It is possible to maintain a stable state without lowering the F transmittance. As a result, the ion source device can be used for a long time. Further, since the discharge chamber is made of an insulator, the discharge means and the magnetic field generation means can be arranged outside the discharge chamber, and the ion source device can have a simple structure. Become.

At this time, it is preferable that the discharge means comprises a coil antenna wound around the side surface of the discharge chamber. With this configuration, it is possible to efficiently generate plasma by the inductively coupled RF discharge. Further, it becomes possible to stably supply a large current of ions.

At this time, the magnetic field generating means is arranged outside the side surface of the discharge chamber, on the side of the discharge electrode of the discharge means and on the opposite side of the discharge electrode of the discharge means. It is preferable to configure it. With this configuration, it is possible to efficiently generate plasma with a small number of magnetic field generating means.

At this time, one magnetic field generating means is disposed outside the side surface of the discharge chamber, on each of the extraction electrode side of the discharge means and on the opposite side of the extraction electrode of the discharge means. It is preferable to configure as described above. With this configuration, it is possible to efficiently generate plasma with a small number of magnetic field generating means.

At this time, it is preferable that the magnetic field generating means comprises an electromagnetic coil connected to a power source whose current can be varied. By configuring in this way,
It is possible to efficiently generate plasma.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is an invention relating to an ion source apparatus S. The ion source device S of the present invention includes a discharge unit 3 for discharging, a discharge chamber 1 having an opening 12 for holding plasma generated by the discharge, and an opening 12 of the discharge chamber 1.
And an extraction electrode 6 for extracting the ion beam from the plasma. The discharge means 3 is the opening 1 of the discharge chamber 1.
It is arranged outside the side surface 13 adjacent to the surface having 2. The discharge chamber 1 is made of an insulator. The discharge means 3 is composed of a coil antenna 3 wound around the side surface 13 of the discharge chamber 1. On the outside of the side surface 13 of the discharge chamber 1, magnetic field generating means 5a and 5b are arranged one by one on the extraction electrode 6 side of the discharge means 3 and on the opposite side of the extraction electrode 6 of the discharge means 3, respectively. . The magnetic field generating means 5a, 5b are electromagnetic coils 5a, 5b connected to a power source 15 whose current can be varied.
Consists of.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The members, arrangements, and the like described below do not limit the present invention and can be variously modified within the scope of the gist of the present invention. This example is an invention relating to an ion source device. The ion source device S of this example is an RF inductively coupled ion irradiation source.

The ion source apparatus S of this example is used in the ion beam assisted vapor deposition method (IBAD).
As shown in FIG. Film forming device 4
A substrate (not shown), a susceptor 42 for holding the substrate, and the like are arranged in the unit 1. The film forming apparatus 41 is connected to a vacuum pump through a pipe (not shown),
It is configured so that the inside can be decompressed. Further, in the film forming device 41, a crucible 43 that serves as a metal evaporation source and an electron gun device 44 are arranged so as to face the susceptor 42. The ion source device S includes an ion extraction electrode 6 which will be described later.
Are arranged so as to face the susceptor 42 that holds the substrate.

The ion source device S of this embodiment is shown in FIG. 1, and has an ion source body 4 which holds the entire ion source device S therein, a discharge tube 1 as a discharge chamber, and a discharge tube 1 inside. A gas inlet 2 for introducing gas, an RF antenna 3 arranged outside the discharge tube 1, an electromagnetic coil 5, and an ion extraction electrode 6 provided so as to close the opening at the upper end of the discharge tube 1. The main component.

The ion source body 4 is made of a stainless steel cylinder, and holds the entire ion source apparatus S therein.
Inside the ion source body 4, a discharge tube 1, a gas inlet 2,
The RF antenna 3, the electromagnetic coil 5, the ion extraction electrode 6 and the like are housed and fixed. As shown in FIG. 2, the ion source body 4 is supported by a base 36, and the bottom surface of the base 36 is fixed to the bottom surface of the film forming apparatus 41. The base 36 is made of stainless steel, and pins are fixed to the upper ends of the legs having a T-shaped cross section. This pin is on the bottom of the ion source body 4,
It penetrates the convex portion provided perpendicularly to the bottom surface. The ion source body 4 is configured so that the irradiation direction of the ion beam can be adjusted with this pin as an axis. The ion source body 4 is covered with an ion source cover 37 on the outer periphery of the side surface.

The discharge tube 1 is made of quartz (glass) having a thickness of about 2 mm, is made of a hollow substantially cylindrical body, and has a closed bottom surface.
The upper surface has an opening 12. The discharge tube 1 constitutes a space for holding plasma which is a source of the ion beam. Although the discharge tube 1 of this example is made of quartz, it may be made of an insulator and the material is not limited to quartz. For example, alumina (aluminum oxide, Al ₂ O ₃ ), silicon nitride (Si
₃ N ₄ ), zirconia (ZrO ₂ ), germanium glass, diamond (C), magnesia (MgO), forsterite (2MgO.SiO ₂ ), steatite (M
gO ・ SiO ₂ ), other electrical resistivity is 10 ¹⁰ Ω ・
Any insulator having a size of about cm or more can be used. The discharge tube 1 is fixed to the ion source body 4 by a discharge tube supporting member 1 a fixed to the inner wall of the ion source body 4.

As shown in FIG. 1, a gas inlet 2 is fixed to the discharge tube 1 approximately at the center of its bottom surface. This gas inlet 2
Is for introducing gas into the discharge tube 1 from the outside of the ion source device S, and the tip for ejecting the gas is located in the discharge tube 1. The gas inlet 2 has an orifice shape with a diameter of 1 mm and is formed so that plasma does not flow back through the gas inlet 2. This gas inlet 2 is
As shown in FIG. 2, it is connected to a gas cylinder 10 via a gas introduction unit 11, and the gas in the gas cylinder 10 can be introduced into the discharge chamber 1. Although the gas cylinder 10 is a single cylinder in FIG. 2, a plurality of cylinders that store different gases may be used, and the gas introduction unit 11 may mix the gas cylinders.

An ion extraction electrode 6 is fixed to the opening 12 on the upper surface of the discharge tube 1 perpendicularly to the discharge tube 1 so as to close the opening 12. The ion extracting electrode 6 plays a role of extracting positive ions from the plasma held in the discharge tube 1. The ion extracting electrode 6 is composed of three well-known electrodes, that is, a first electrode 7, a second electrode 8 and a third electrode 9, and these three electrodes are arranged in layers from the discharge tube 1 side toward the outside. .

The first electrode 7, the second electrode 8 and the third electrode 9 are
It is made of molybdenum that is not easily corroded by oxygen, and is composed of a plate-shaped body having a predetermined thickness. Further, as shown in FIG. 1, the central portion is formed in a substantially spherical arc surface which is convex toward the outside of the discharge chamber 1. The first electrode 7, the second electrode 8, and the third electrode 9 are provided with a large number of ion extraction holes (not shown) penetrating the electrodes 7 to 9 in the thickness direction, and discharge is performed through the ion extraction holes. Tube 1
Ions can be extracted from the inside.

The first electrode 7, the second electrode 8 and the third electrode 9 are
A predetermined interval, for example, 1
Spacers (not shown) for inserting a space of mm are inserted and fixed to the ion source body 4 with bolts or the like. The spacer is made of alumina capable of maintaining electrical insulation, and the first electrode 7, the second electrode 8 and the third electrode 9 are insulated from each other.

As shown in FIG. 3, the positive electrode terminal of the acceleration power source 17 is connected to the first electrode 7 so that a positive voltage can be applied. As shown in FIG. 3, the negative electrode terminal of the suppressor power supply 18 is connected to the second electrode 8 and is configured so that a negative voltage can be applied. Since the third electrode 9 is directly fixed to the ion source body 4 which is grounded 19, the potential is the same ground as the ion source body 4. By connecting a well-known neutralizer to the third electrode 9, it is possible to prevent ions from accumulating in the acceleration electrode 8 and reducing the efficiency of extracting ions. here,
The neutralizer is a device that supplies electrons and controls the ion value to maintain an electrically neutral state.

An RF antenna 3 is arranged outside the side surface 13 of the discharge tube 1 so as to be wound around the outer periphery at a constant distance from the side surface 13. The antenna 3 is made of a stainless pipe having a diameter of about 6 mm. The antenna 3 includes two legs 31 and 31, and the legs 31 and 31 are fixed to the bottom surface of the ion gun body 4. The antenna 3 extending from one leg portion 31 is formed so as to reach the other leg portion 31 after being wound outside the side surface 13 of the discharge tube 1.
It should be noted that FIG. 1 shows only one of the two legs 31, 31.

The antenna 3 is supported by the antenna support member 35 as shown in FIG. This antenna support member 35
Are fixed to the circumference of an electrode supporting member 6b described later with bolts, and the ion gun body 4 is inserted through the electrode supporting member 6b.
It is fixed to. The antenna support member 35 is the discharge tube 1
A protrusion 35a capable of catching the antenna 3 is formed on the side, and the antenna 3 is configured so as not to fall below the protrusion 35a.

The antenna 3 is, as shown in FIGS.
It is connected to an RF power source 34 via a matching box 33 for controlling current. Matching box 3
The positive side of 3 is one leg 31, the matching box 3
The minus side of 3 is connected to the other leg 31. R
When a high frequency current flows from the F power source 34 to the antenna 3, an induced electromotive force is generated, and plasma is generated in the discharge tube 1 by the inductively coupled RF discharge. Further, the antenna 3 is provided with a cooling water pipe (not shown) inside thereof over the entire length. Figure 2
Cooling water is introduced into the antenna 3 through the cooling water pipe 38, and the antenna 3 can be cooled.

The electromagnetic coil 5 is composed of two electromagnetic coils, an upper electromagnetic coil 5a and a lower electromagnetic coil 5b. The configuration of the electromagnetic coil 5 including the upper electromagnetic coil 5a and the lower electromagnetic coil 5b is shown in FIG. The electromagnetic coil 5 includes an electromagnetic coil in which a copper wire 52 is wound around a copper bobbin 51. The bobbin 51 is provided with a concave groove on the entire outer circumference and has a U-shaped cross section and a ring shape. The copper wire 52 is the bobbin 51.
The magnetic flux density is about 0.1 T when a current of 10 A is applied.

The diameter of the inner surface 53 of the bobbin 51 is slightly larger than the diameter of one turn of the antenna 3 wound around the discharge tube 1. When assembling the ion source device S, the discharge tube 1 is provided inside the bobbin 51 so that the bobbin 51 and the discharge tube 1 are coaxial. That is, the side surface 13 of the discharge tube 1 is arranged so as to surround the inner surface 53 of the bobbin 51.

The upper electromagnetic coil 5a is a coil holding member 6
The coil holding member 6c is fixed to the upper coil supporting member 6a with a bolt. The coil holding member 6c is made of a non-magnetic material, is provided with a concave groove into which the electromagnetic coil 5 can be fitted, and has a U-shaped cross section. The upper coil support member 6 a is formed in a ring shape having substantially the same outer circumference as the inner wall of the ion source body 4, and is fixed to the ion source body 4.

The lower electromagnetic coil 5b is housed in the coil holding member 6d, and the coil holding member 6d is fixed to the lower coil supporting member 6b with bolts. The lower coil support member 6b and the coil holding member 6d have the same material and shape as the upper coil support member 6a and the coil holding member 6b, and are fixed to the ion source body 4. An antenna support member 35 is fixed to the lower coil support member 6b with bolts at a position that divides the ring-shaped circumference into three equal parts.

The antenna support member 35 is arranged so that the inner end of the antenna support member 35 is closer to the inner side than the coil holding members 6b and 6d (closer to the discharge tube 1). As a result, the position of the antenna 3 is arranged closer to the inside than the upper electromagnetic coil 5a and the lower electromagnetic coil 5b. The positions of the upper electromagnetic coil 5a and the lower electromagnetic coil 5b are substantially symmetrical around the antenna 3.

Upper electromagnetic coil 5a, lower electromagnetic coil 5b
Are connected to the coil power supply 15 as shown in FIG. The coil power supply 15 is a power supply whose current can be varied in the range of 0 to 10A. The upper electromagnetic coil 5a and the lower electromagnetic coil 5b are 0.0 when the current is changed in the range of 0 to 10A.
The magnetic field strength is about 0.1T.

Next, the operation of the ion source device S of this example will be described. First, the air inside the film forming apparatus 41 is evacuated by a vacuum pump (not shown) connected to the film forming apparatus 41 to 10 ^−3.
A high vacuum state of about Pa to 10 ⁻⁵ Pa is set. As a result, the inside of the ion gun body 4 which is continuous via the ion extracting electrode 6 is also in a high vacuum state of about 10 ⁻³ Pa to 10 ⁻⁵ Pa. Next, the gas introduction unit 11 is operated to introduce the gas in the gas cylinder 10 into the discharge chamber 1 through the gas introduction port 2 in an amount of 30 to 100 sccm. At this time, oxygen gas is introduced. Instead of oxygen gas, argon gas, nitrogen gas, fluorine gas, or a mixed gas in which these gases and oxygen gas are appropriately combined may be introduced.

When the inside of the ion gun body 4 reaches a predetermined gas pressure, the coil power supply 15 is turned on and the current is set to 3A.
Then, the magnetic field is generated in the electromagnetic coil 5. Then R
The F power supply 34 is turned on, and the antenna 3 receives a high frequency (13.
(56 MHz) current is passed and the antenna 3 discharges. Due to the induced electromotive force caused by the high frequency current of the antenna 3,
The gas is ionized and plasma is generated in the discharge tube 1 surrounded by the antenna 3 and the electromagnetic coil 5 in the ion gun body 4.
This RF discharge is called inductive coupling type discharge. Electrons existing in vacuum vibrate due to high frequency,
When this collides with the neutral gas introduced from the gas inlet 2, neutral gas molecules are ionized and plasma is generated.

The matching of the matching box 33 is set to auto and the RF power source 34 is automatically controlled. As a result, it is possible to always maintain stable plasma with respect to fluctuations in the gas amount, and it is possible to always stably supply ions with a large current of 1 A or more.

Since the discharge tube 1 is made of quartz, which is an insulator, the electric field generated by the discharge of the antenna 3 and the magnetic field generated by the electromagnetic coil 5 reach the discharge tube 1 and plasma is generated in the discharge tube 1. After that, the acceleration power supply 17 and the suppressor power supply 18
Is turned on, and a positive voltage, for example, a positive potential voltage of 1000V is applied to the first electrode 7, and a negative voltage, for example, a negative potential voltage of 1000V is applied to the second electrode 8.
A potential difference is generated between the first electrode 7 and the second electrode 8 to cause an acceleration field. Due to this acceleration field, positive ions in the plasma generated in the discharge tube 1 are extracted from an ion extraction hole (not shown), and an ion beam is formed.

As described above, an ion beam of argon, oxygen, nitrogen or the like is extracted from the ion source device S.
When the ion source apparatus S of this example is operated under the above conditions,
Ion extraction voltage of 1000 V at 1 to 3 seconds after the acceleration power supply 17 and suppressor power supply 18 are turned on.
It was confirmed that a high current ion beam of 1 A was extracted at (1.5 kW power) by monitoring the extracted ions by a known method.

Further, the acceleration power supply 17 and the suppressor power supply 18
According to the Faraday probe, it was found that, after 1 to 3 seconds after the power was turned on, at a position 1 m away from the ion source apparatus S, 300 μA / cm ² or more was uniformly transported within Φ200 mm. Confirmed by ion amperometry. In addition, the ion source device S is provided in a state where there is no magnetic field that does not flow current in the upper electromagnetic coil 5a and the lower electromagnetic coil 5b.
Was operated under the above conditions, it was found that a large current ion of 400 mA was obtained when the ion extraction voltage was 1000 V (power of 1.5 kW) 1 to 3 seconds after the power of the acceleration power supply 17 and the suppressor power supply 18 was turned on. The fact that the beam was extracted was confirmed by the ion current measurement method using a Faraday probe.

When a conventional ion source device such as the ion source device shown in FIGS. 6 and 7 is used, it is normally 800 mA at 6 to 8 kW.
In comparison with the fact that an ion beam of about 300 μA / cm ² is transported within about 30 to 40 mm at a position 1 m away, the ion source device S of this example
It was confirmed that a high-current ion beam can be efficiently extracted.

The ion source apparatus S of this example is used, for example, in the ion beam assisted vapor deposition apparatus shown in FIG. In the ion beam assisted deposition, the metal evaporation source in the crucible 43 provided facing the substrate is irradiated with the electron beam generated by the electron gun device 44 to evaporate the metal vapor. At the same time, the ion source apparatus S of the present example is operated in the above procedure to generate an ion beam. Thus, the metal vapor deposition particles and the ion beam are simultaneously supplied to the substrate. When a rare gas ion beam such as argon is generated, it is possible to change the properties of the thin film such as improving the crystallinity. When an ion beam of nitrogen, oxygen, etc. is generated, a compound thin film of nitride, oxide, etc. can be formed.

Although the case where the ion source apparatus S is used for the ion beam assisted vapor deposition method has been described in the present example, the ion source apparatus S of the present example may be used for the ion beam etching. This ion beam etching system
A vacuum container, a substrate arranged in the vacuum container, and an ion source device S of this example arranged so that the ion extraction electrode 6 faces the substrate. The ion beam etching is performed by arranging the substrate and depressurizing the inside of the vacuum container, and then irradiating the substrate with the ion beam generated by the ion source apparatus S of the present example according to the above procedure. The ion beam etching has a merit that perfect anisotropy can be realized.

[0042]

As described above, according to the present invention, since the discharging means is arranged outside the side surface adjacent to the surface having the opening of the discharge chamber, the discharging means such as the RF coil antenna is provided. It is possible to prevent the occurrence of contamination due to sputtering during the operation of the ion source device, and it is possible to supply the ion beam in a clean environment. as a result,
It is possible to prevent the metal film originating from the discharge means from adhering to the inner wall of the discharge chamber, and to maintain a stable state without reducing the RF transmittance of the inner wall of the discharge chamber. As a result, the ion source device can be used for a long time.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional explanatory view showing an ion source device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a connection of devices when the ion source device according to an embodiment of the present invention is used in an ion beam assisted vapor deposition method.

FIG. 3 is a schematic explanatory view schematically showing an ion source device according to an embodiment of the present invention.

FIG. 4 is a vertical cross-sectional explanatory view showing a part of an ion source device according to an embodiment of the present invention.

FIG. 5 is a schematic explanatory view showing an electromagnetic coil according to an embodiment of the present invention.

FIG. 6 is an explanatory view showing a conventional ion source device.

FIG. 7 is an explanatory diagram showing a conventional ion source device.

[Explanation of symbols] S ion source device 1 discharge tube 1a Discharge tube support member 2 gas inlet 3 RF antenna 4 Ion source body 5 electromagnetic coil 5a Upper electromagnetic coil 5b Lower electromagnetic coil 6 Ion extraction electrode 6a Upper coil support member 6b Lower coil support member 6c, 6d coil holding member 7 First electrode 8 Second electrode 9 Third electrode 10 gas cylinders 11 Gas introduction unit 12 openings 13 sides 17 Accelerating power supply 18 suppressor power supply 19 Earth 31 legs 33 Matching Box 34 RF power supply 35 Antenna support member 35a protrusion 36 foundation 37 Ion source cover 38 Cooling water piping 39 Noise cut filter 41 film deposition equipment 43 Crucible 44 electron gun device 51 bobbins 52 copper wire 53 Inside

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Susumu Kumagawa             3-2-6 Minamioi, Shinagawa-ku, Tokyo Stocks             Inside company Syncron F-term (reference) 4K029 CA09 DE02 EA09                 5C030 DD01 DE04 DE07

Claims (5)

[Claims] 1. A discharge unit for performing discharge, a discharge chamber having an opening for holding plasma generated by the discharge, and a drawer for drawing out an ion beam from the plasma by closing the opening of the discharge chamber. An ion source device comprising an electrode, wherein the discharge means is arranged outside a side surface adjacent to a surface of the discharge chamber adjacent to the surface, and the discharge chamber is made of an insulator. Ion source device. 2. The ion source device according to claim 1, wherein the discharge means comprises a coil antenna wound around the side surface of the discharge chamber. 3. A magnetic field generating means is arranged outside the side surface of the discharge chamber, on each of the discharge electrode side of the discharge means and on the opposite side of the discharge electrode of the discharge means. The ion source device according to claim 1, wherein: 4. A magnetic field generating means is arranged outside the side surface of the discharge chamber, one magnetic field generating means on each of the discharge electrode side of the discharge means and on the opposite side of the discharge electrode of the discharge means. The ion source device according to claim 1, wherein: 5. The ion source device according to claim 3, wherein the magnetic field generating means is composed of an electromagnetic coil connected to a power source whose current can be varied.