JPH07220672A - Ion beam device - Google Patents

Abstract

PURPOSE:To generate a large diameter and uniform ion beam, and easily per form highly accurate work by arranging a target in a vacuum vessel so that a distance to an end part of a permanent magnet on an outside surface of a plasma generator is situated in a position of specific intensity of a magnetic field created by the permanent magnet. CONSTITUTION:A target 41 and a substrate 42 are installed in a vacuum vessel 43 respectively through support means 71 and 82, and in that case, the target 41 and the substrate 42 installed in the vacuum vessel 43 are arranged so that a distance (Z) to an end part of a permanent magnet 33 arranged on an outside surface of a plasma generator 32 is situated in a position where intensity of a magnetic field by the permanent magnet 33 is one gauss or less, or in a position in the same degree with the earth magnetism, or that the distance (Z) to the end part of the permanent magnet is separated 60mm or more. The support means 71 rotatably supports the target 41, and enables an ion beam to irradiate the target 41 while rotating it in order to uniformly perform work of the targer 41.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion beam apparatus, and more particularly, to an ion beam applied to a target to process the target or make a thin film, for example, production and processing of a large-scale magnetic thin film or semiconductor. The present invention relates to a suitable ion beam device.

[0002]

2. Description of the Related Art The target surface is processed by irradiating the target with an ion beam having an energy of about 200 to 5000 eV to physically sputter or chemically etch the target or to face the target. There is known a device for forming a thin film on a substrate to be heated.

As such an apparatus, there is a conventional one having a structure shown in FIG. That is, in the apparatus shown in the figure, a neutral gas is introduced into the cylindrical plasma generation container 1 through the gas introduction port 2, and arc discharge is caused by the filament 3 and the anode 4.
Processing of the target 7 is performed by extracting an ion beam from the resulting plasma using the electric fields of the extraction electrodes 5 and 6 and irradiating the target 7 with sputtering to perform etching.
Alternatively, a thin film is formed on the substrate 8 facing the target 7. The target 7 and the substrate 8 are housed in a vacuum container 9 and the inside of the vacuum container 9 is evacuated by a vacuum pump 11. The solenoid coil 10 provided on the outer circumference of the cylindrical plasma generation container 1 has an important function of improving the efficiency of plasma generation and operating with a low gas amount.

However, as the manufacturing and processing of the thin film becomes large in scale and the ion beam diameter becomes large, the cylindrical plasma generating container 1 also becomes large in diameter, so that the solenoid coil 1
0 becomes large, and the leakage magnetic field generated by the solenoid coil 10 to the target 7 or the substrate 8 becomes large. When the leakage magnetic field is large, it becomes difficult to control the magnetic anisotropy and the like of the magnetic film, and the performance deteriorates. Further, the ion beam extracted by the leakage magnetic field is bent, the parallelism of the ion beam is deteriorated, and the processing accuracy is reduced.

In manufacturing and processing a thin film using an ion beam, in order to obtain high processing accuracy, the uniformity of the ion beam is high, the divergence angle of the ion beam is small, and You need to be good.

[0006]

However, in the above-described ion beam apparatus, the plasma in the vicinity of the inner wall of the cylindrical plasma generation container 1 is cooled by the wall of the cylindrical plasma generation container 1 to generate plasma loss. As a result, the plasma density distribution is high at the center of the opening of the cylindrical plasma generation container 1 and is low as it approaches the end of the opening.

Therefore, the plasma pressure on the surface of the extraction electrode 5 is affected, but the plasma pressure also increases the electric field formed in the opening on the extraction electrode in the central portion of the extraction electrode and in the peripheral portion thereof. . Therefore, the electric field formed in the openings on the extraction electrodes 5 and 6 is different between the openings located in the central part and the peripheral parts.

Due to the non-uniformity of the plasma density distribution and the electric field, it is difficult to obtain a uniform ion beam, and therefore, it has been difficult to perform high-precision machining by the conventional ion beam apparatus.

The present invention has been made in view of the above points,
It is an object of the present invention to provide an ion beam apparatus having a large diameter and capable of generating a uniform ion beam and easily performing highly accurate processing.

[0010]

According to the present invention, a plasma generating container for ionizing a neutral gas to generate plasma, and magnetic poles having different polarities are alternately arranged on the outer surface of the plasma generating container. A permanent magnet, an ion source having an extraction electrode for extracting ions from the plasma in the plasma generation container as an ion beam, and a target that is sputtered or etched by the ion beam extracted by the extraction electrode, or is placed opposite to the target A vacuum container for accommodating and supporting a substrate on which a film is to be formed, and a target housed in the vacuum container, or a target and a substrate, and a permanent magnet end portion arranged on an outer surface of the plasma generating container. The distance is such that the strength of the magnetic field generated by the permanent magnet is 1 gauss or less, or the position that is approximately the same as the earth's magnetism, or the The distance between the magnet end, characterized in that an ion beam apparatus which is arranged closer than 60 mm.

[0011]

In other words, in order to efficiently generate plasma and confine it in a predetermined space to have a large diameter and to extract a uniform ion beam, the magnetic field is sufficiently weak near the extraction electrode and the magnetic field near the plasma generation container surface. Is sufficiently strong that the generated plasma must be confined without touching the wall surface of the plasma generation container.

When the present inventors use the method of confining the plasma with the magnetic field in which the N pole and the S pole of the permanent magnet are alternately arranged, the magnetic field in the vicinity of the permanent magnet is much larger than the magnetic field of the solenoid coil. Regardless, a few cm from the permanent magnet row
It is found from the analysis result of the magnetic field distribution that the magnetic field rapidly decreases when it is separated, and it easily becomes the geomagnetic level. If the goodness is confirmed by an experiment and the target, or the target and the substrate are placed at this position, the above-mentioned object is achieved, and it is suitable for the microfabrication of magnetic thin films, semiconductors, and the manufacturing apparatus.

[0013]

The present invention will be described in detail below with reference to the illustrated embodiments.

1 and 2 show an embodiment of the ion beam processing apparatus of the present invention. In FIG. 1, the cathode 31
Is made of a hairpin-shaped tungsten filament, which emits thermoelectrons. The cylindrical plasma generation container 32 forming the plasma generation chamber is made of a non-magnetic material and also serves as an anode electrode for causing arc discharge with the cathode 31.

As shown in FIG. 2, a large number of permanent magnets 33 are provided on the outer periphery of the plasma generating container 32 so that the polarities of the magnetic poles are alternately changed along the circumferential direction on the outer surface of the plasma generating container 32. There is. The plasma generation container 32 is, for example, made of stainless steel having an inner diameter of 150 mm, an outer diameter of 156 mm, and a depth of 150 mm, and is provided with permanent magnets 33 having a width of 8 mm, a height of 25 mm, and a length of 150 mm magnetized in the height direction on a 16-row cylinder. Two permanent magnets each having a width of 120 mm and a length of 120 mm and having a length of 40 mm are provided on the side surface on the side where the filament 31 is held. For the residual magnetization of the permanent magnet 33, a cobalt samarium magnet of 8500 gauss was used. Therefore, the plasma generating container 32 is made of a non-magnetic material such as stainless steel so that the magnetic lines of force of the permanent magnet 33 can be formed inside.

A direct current voltage is applied between the cathode 31 and the plasma generation container 32, plasma is generated by arc discharge at low pressure, and extraction electrodes for extracting ions from this plasma as an ion beam have a large number of apertures 45 in each.
It is composed of extraction electrodes 36 and 37 composed of a plasma electrode (shown in FIG. 2) and an acceleration electrode. In this way, the ion source 30 is configured.

On the other hand, the target 41 and the substrate 42 are mounted in the vacuum container 43 via the supporting means 71 and 81, respectively. At that time, the target 41 and the substrate 42 mounted in the vacuum container 43 are The distance (Z) from the end of the permanent magnet 33 arranged on the outer surface of the plasma generation container 32 is such that the strength of the magnetic field generated by the permanent magnet 33 is 1 gauss or less, or at the same level as the earth magnetism. ,
Alternatively, the distance (Z) from the end of the permanent magnet is 60 mm or more.

The inside of the vacuum container 43 is evacuated by a vacuum pump 44, and the extraction electrodes 36 and 37 of the vacuum container 43 are further exhausted.
An opening 43A for guiding the ion beam extracted by the extraction electrodes 36 and 37 into the vacuum container 43 is provided on the side. The supporting means 71 rotatably supports the target 41 and irradiates the target 41 with an ion beam while rotating the target 41 in order to uniformly process the target 41. In this way, the vacuum container 43 is configured.

Further, in this embodiment, the ion source 30 having the above-mentioned structure and the vacuum container 43 are connected to each other to form an ion beam processing apparatus. Upon connection, the ion source 30
The extraction electrode 36, 37 side end (usually an insulating flange supporting the electrode) and the opening 43A side end of the vacuum container 43 are connected to each other to extract the ion beam extracted by the extraction electrode 36, 37. It is adapted to be introduced into the vacuum container 43 for irradiation.

When a thin film is formed on the substrate 42,
The substrate 42 is placed on the supporting means 81, and on the supporting means 71,
For example, when a permalloy plate is placed and an ion beam is applied to the permalloy plate to perform sputtering, the scattered particles adhere to the substrate 42 to form a thin film.

In the structure of this embodiment described above, argon gas is introduced as the neutral gas 35 (the inlet is 34),
Comparing the efficiency of creating plasma when the permanent magnet 33 is removed and the efficiency of creating plasma when the permanent magnet 33 is provided with respect to argon ion plasma, when the required arc power is compared, Arc power is 1/4 ~
It was found that there is an effect that can be reduced to 1/5 or less.

Therefore, it was found that even with respect to argon gas, the plasma generation using the permanent magnet 33 can be efficiently performed through the nonmagnetic plasma generation container 32.

FIG. 3 shows the magnetic field distribution created by the permanent magnet 33 of FIG. It can be seen that when the distance (Z) is 60 mm or more from the end of the permanent magnet 33 on which the target 41 and the substrate 42 are installed, it is approximately 1 Gauss or less, which is about the same as the geomagnetism. It can also be seen that the magnetic field is approximately the level of geomagnetism even when the distance (Z) is about 15 mm and the distance (R) from the center of the beam is about 35 mm.

As described above, since the magnetic field is sufficiently small in the sufficiently wide range of the extraction electrodes 36 and 37, an ion beam having a large diameter and a uniform diameter can be obtained. As shown in FIG. 2, a strong magnetic field 48 for confining the plasma is generated along the wall surface of the plasma generation container 32, and the plasma is prevented from directly contacting the wall surface of the plasma generation container 32, so that the plasma can be sufficiently confined. And a uniform plasma density distribution can be obtained.
Moreover, it contributes to obtaining an ion beam having a large diameter.

While the strong magnetic field 48 sufficiently confines the plasma, the electrons emitted from the filament 31 are
After repeated collisions with molecules such as argon gas, it is possible to lose its energy and reach the wall surface of the plasma generating container 32 that travels along the magnetic field 48 and forms the anode.

Further, as is apparent from FIG. 1, only the filament 31 is installed in the plasma generating container 32. Therefore, the apparatus of this embodiment is easy to disassemble, easy to clean, and easy to maintain. Good nature.

[0027]

According to the ion beam apparatus of the present invention described above, a plasma generating container for ionizing a neutral gas to generate plasma, and magnetic poles having different polarities are alternately arranged on the outer surface of the plasma generating container. So provided, an ion source having an extraction electrode for extracting ions from the plasma in the plasma generation container as an ion beam, and a target or a target that is sputtered or etched by the ion beam extracted by the extraction electrode. And a vacuum container for accommodating and supporting a substrate on which a film is to be formed, the target being accommodated in the vacuum container, or the target and the substrate being permanently disposed on the outer surface of the plasma generating container. The distance from the magnet end is at a position where the strength of the magnetic field created by the permanent magnet is 1 gauss or less, or as much as the geomagnetism. In this case, the leakage magnetic field is greatly reduced to the same level as the earth's magnetism, and the parallelism of the ion beam is smaller than that of the conventional device. The target, or target and substrate, is placed at this position, which makes it possible to perform high-precision microfabrication on magnetic thin films and semiconductors, as well as accurate magnetic anisotropy. Since it can be applied to a magnetic thin film, a higher performance magnetic thin film can be produced. Furthermore, since the ion beam diameter is large and a uniform ion beam can be generated, it is possible to obtain an ion beam apparatus suitable for high-precision manufacture and processing of large-scale magnetic thin films and semiconductors.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an ion beam thin film manufacturing and processing apparatus of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a characteristic diagram showing a magnetic field distribution in the device of the present invention.

FIG. 4 is a configuration diagram of a conventional thin film manufacturing and processing apparatus using an ion beam.

[Explanation of symbols]

1, 32 ... Plasma generating container, 5, 6, 36, 37 ... Extraction electrode, 7, 41 ... Target, 8, 42 ... Substrate,
9, 43 ... Vacuum container, 30 ... Ion source, 33 ... Permanent magnet, 43A ... Opening portion, 71, 81 ... Supporting means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaru Higaki 3-1-1, Saiwaicho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi Research Laboratory

Claims (6)

[Claims] 1. A plasma generating container for generating plasma by ionizing a neutral gas, and permanent magnets provided so that magnetic poles of different polarities are alternately arranged on the outer surface of the plasma generating container.
An ion source having an extraction electrode for extracting ions as an ion beam from plasma in the plasma generation container, and a vacuum container for accommodating and supporting a target processed by the ion beam extracted by the extraction electrode. The target housed in is located at a position where the distance from the end of the permanent magnet arranged on the outer surface of the plasma generation container is such that the strength of the magnetic field generated by the permanent magnet is 1 gauss or less. An ion beam device characterized in that 2. A plasma generating container for generating plasma by ionizing a neutral gas, and permanent magnets provided so that magnetic poles of different polarities are alternately arranged on the outer surface of the plasma generating container.
An ion source having an extraction electrode for extracting ions as an ion beam from plasma in the plasma generation container, and a vacuum container for accommodating and supporting a target processed by the ion beam extracted by the extraction electrode. The target housed in is located at a position where the distance from the end of the permanent magnet arranged on the outer surface of the plasma generation container is such that the strength of the magnetic field produced by the permanent magnet is approximately the same as the earth's magnetism. An ion beam device characterized in that 3. A plasma generating container for ionizing a neutral gas to generate plasma, permanent magnets provided so that magnetic poles of different polarities are alternately arranged on the outer surface of the plasma generating container,
An ion source having an extraction electrode for extracting ions as an ion beam from plasma in the plasma generation container, and a vacuum container for accommodating and supporting a target processed by the ion beam extracted by the extraction electrode. 2. The ion beam device, wherein the target housed in is located 60 mm or more away from the end of the permanent magnet arranged on the outer surface of the plasma generating container. 4. A plasma generating container for generating plasma by ionizing a neutral gas, and permanent magnets provided so that magnetic poles of different polarities are alternately arranged on the outer surface of the plasma generating container.
An ion source having an extraction electrode that extracts ions as an ion beam from the plasma in the plasma generation container, a target that is sputtered by the ion beam that is extracted by the extraction electrode, and particles that are scattered by the sputtering of the target are attached. A vacuum container for accommodating and supporting the substrate to be deposited, wherein the target and the substrate accommodated in the vacuum container are
An ion beam device characterized in that the distance from the end of the permanent magnet arranged on the outer surface of the plasma generating container is such that the strength of the magnetic field produced by the permanent magnet is 1 gauss or less. . 5. A plasma generating container for ionizing a neutral gas to generate plasma, permanent magnets provided so that magnetic poles of different polarities are alternately arranged on the outer surface of the plasma generating container.
An ion source having an extraction electrode that extracts ions as an ion beam from the plasma in the plasma generation container, a target that is sputtered by the ion beam that is extracted by the extraction electrode, and particles that are scattered by the sputtering of the target are attached. A vacuum container for accommodating and supporting the substrate to be deposited, wherein the target and the substrate accommodated in the vacuum container are
An ion beam, characterized in that the distance from the end of the permanent magnet disposed on the outer surface of the plasma generating container is such that the strength of the magnetic field produced by the permanent magnet is approximately the same as the earth's magnetism. apparatus. 6. A plasma generating container for ionizing a neutral gas to generate plasma, and permanent magnets provided so that magnetic poles having different polarities are alternately arranged on the outer surface of the plasma generating container.
An ion source having an extraction electrode for extracting ions as an ion beam from the plasma in the plasma generation container, a target sputtered by the ion beam extracted by the extraction electrode, and particles scattered by the sputtering of the target are attached. A vacuum container for accommodating and supporting the substrate to be deposited, wherein the target and the substrate accommodated in the vacuum container are
An ion beam device characterized in that the distance from the end of the permanent magnet disposed on the outer surface of the plasma generating container is 60 mm or more.