JP2004022212A - Magnetic neutral line electrical discharge plasma treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic neutral line discharge plasma treatment device in which the dimensions in longitudinal direction of the vacuum chamber generating plasma is shortened as much as possible and weight saving and simplicity are realized and the cost can be reduced without using a high-cost wall material such as ceramics, while maintaining generation of a low cost, low temperature plasma and time-space and spatial control concerning the size and the location of the generated plasma. <P>SOLUTION: In the discharge plasma treatment device, the magnetic field generating means comprises a cylindrical magnet constructed so that a first end along the axis of the device constitutes N-pole and a second end constitutes S-pole and a constant current coil provided coaxially with the cylindrical magnet on its outside, and by changing the current value flowing to the constant current coil, the diameter of the annular magnetic neutral conductor formed by the cylindrical magnet and the constant current coil can be established freely. The electric field generating means is arranged in the vacuum chamber so that the high frequency electric field may be applied in the inclined direction including right angles to the magnetic neutral conductor generated in the vacuum chamber by the magnetic field generating means. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a discharge plasma processing apparatus that performs processing such as etching, sputtering, coating, and CVD on an object to be processed such as a substrate and a target using plasma.
[0002]
[Prior art]
The existence of a magnetic neutral-ray discharge plasma processing apparatus has been established in Japanese Patent Nos. 2,058,897 and 3,177,573, and its effectiveness has been recognized and industrial results have been obtained. The magnetic neutral loop discharge: wherein no other method has the (Magnetic N eutral L ine D ischarge NLD also abbreviated) plasma method are mainly two.
[0003]
One feature is that it has spatio-temporal control over the size and position of the plasma to be generated, that is, it can freely change the required size and position of the plasma both temporally and spatially. This is because a magnetic neutral wire can be easily installed in a vacuum chamber, and a plasma is generated along its shape. This degree of freedom is not found in other systems. Another feature is that during the plasma generation process that can be performed by the NLD method, the electrons are subjected to the rf electric field in the region including the zero magnetic field, and the energy is crossed many times while obtaining the energy. Under the conditions, even if the power to be injected is increased, the increase in the internal energy of the electron group, 3 / 2kneTe (where ne: electron density, Te: the same temperature, k: Boltzmann constant) concentrates exclusively on the increase in density. In addition, since the temperature is kept almost at a low temperature, there are few high-temperature components unnecessary for the surface treatment, and the processing speed is increased by increasing the density. Due to these two features, the magnetic neutral line discharge plasma processing equipment has outstanding performance in ultra-fine processing in fields such as glass processing of micro lenses and optical waveguides and etching of low dielectric constant materials, which require increasingly precise processing accuracy. It is a state of pride.
[0004]
FIG. 6 of the accompanying drawings is a conceptual diagram of an induction magnetic field type magnetic neutral ray discharge plasma processing apparatus manufactured for the purpose of processing many disk-shaped substrate surfaces. A circular magnetic neutral wire E is formed in the vacuum chamber A by adjusting the current flowing through the upper, middle, and lower coils B, C, and D that are coaxially installed outside the cylindrical vacuum chamber A. . To generate the plasma, a doughnut-shaped donut centered on a circular magnetic neutral line E is generated by an azimuthally induced electric field generated by an excitation current flowing through an rf coil G wound on the outside of an insulating cylindrical vacuum wall F such as ceramic. A plasma is generated. At this time, the diameter and the vertical position of the donut plasma can be freely controlled even during processing, by a combination of currents flowing through the three coils B, C, and D.
[0005]
The characteristic of the plasma itself of the magnetic neutral line discharge plasma thus generated is that high-density and low-temperature plasma is generated using a low-pressure gas as described in [] 0004]. The features are extremely suitable for various types of processing, and there is a strong demand for improving the performance of the apparatus while maintaining features not found in other methods.
[0006]
[Problems to be solved by the invention]
Despite the outstanding performance as described above, there is a need to improve the magnetic neutral discharge plasma processing apparatus from the viewpoint of ease of use as the processing apparatus and shortening of the maintenance adjustment period.
[0007]
That is, in the conventional three-magnetic-field coil processing apparatus as shown in FIG. 6, the number of magnetic field coils is reduced as much as possible from the viewpoint of the arrangement of other components of the plasma processing apparatus, and the weight of the apparatus is reduced. It is realistically required to reduce the weight and energy consumption.
[0008]
In addition, in the case of a conventional circular magnetic neutral ray discharge plasma processing apparatus as shown in FIG. 6, in order to apply an electric field along the magnetic neutral line in a circular shape, in principle, a cylindrical porcelain container is used as a side wall of the vacuum chamber. A one-turn coil for high frequency (rf) had to be wound around the outside. However, a thick cylindrical porcelain container having a diameter of several tens of cm is expensive, and no matter how smooth the inner surface on the vacuum side, it is necessary to take measures to remove or prevent adsorption by affinity with a special gas. . In addition, strong and vacuum-resistant wall materials such as ceramics are expensive and increase the price of the device itself. This tendency becomes more pronounced as the size of the device increases.
[0009]
In view of the above, the present invention has been developed to improve the configuration of the magnetic field generating means to shorten the longitudinal dimension of the apparatus, that is, the longitudinal dimension of the vacuum chamber portion for generating plasma as much as possible to reduce the weight and weight of the magnet. A first object is to provide a glow discharge plasma processing apparatus.
[0010]
A second object of the present invention is to provide a magnetic neutral beam discharge plasma processing apparatus capable of reducing the weight of the apparatus and reducing the cost of the apparatus without using an expensive wall material such as ceramic while reducing the weight and weight. It is in.
[0011]
[Means for Solving the Problems]
In order to achieve the first object, according to the present invention, there is provided a magnetic field generating means for generating a magnetic neutral line formed by a series of positions of zero magnetic field which are continuously present in a vacuum chamber; Means for generating a discharge plasma in a space containing the magnetic neutral line by applying a high-frequency electric field to the magnetic neutral line generated in the vacuum chamber; In a discharge plasma processing apparatus for processing an object to be processed, a magnetic field generating means includes a cylindrical magnet configured so that a first end is an N pole and a second end is an S pole along an axis of the apparatus, and a magnetic field is generated outside the cylindrical magnet. Consisting of a cylindrical magnet and a constant current coil provided coaxially, the diameter of the annular magnetic neutral wire formed by the cylindrical magnet and the constant current coil can be set arbitrarily by changing the current flowing through the constant current coil. It is special that It is set to.
[0012]
Although it is described in Japanese Patent No. 2705897 that a three-coil system is necessary for precise control of the form of the closed magnetic neutral wire, its size, and the position in the vertical direction, as described in Japanese Patent No. Since the necessity of the position control is to control the distance to the surface of the object to be processed, the vertical position control can be performed by the set height of the surface to be processed. As a result, the present invention employs a one-field coil system instead of the conventional three-coil system to control the size of the closed magnetic neutral line, thereby reducing the weight of the entire apparatus and reducing the weight of the apparatus. Is brought about.
[0013]
In an apparatus for achieving the first object of the present invention, as an electric field generating means for generating a discharge plasma in a space including a magnetic neutral line by applying a high-frequency electric field to a magnetic neutral line generated in a vacuum chamber. May be of an inductive type or a capacitive type.
[0014]
Preferably, the magnetic field generating means may be configured to have a circular, polygonal or elliptical axial symmetry having the same shape as the surface of the workpiece.
[0015]
Further, the magnetic field generating means may be constituted by a direct current, an alternating current including a commercial frequency or a combination of a direct current and an alternating current including a commercial frequency.
[0016]
In order to achieve the second object of the present invention, the electric field generating means is provided in the vacuum chamber so as to apply a high-frequency electric field in a tilt angle direction including a right angle with a magnetic neutral line generated in the vacuum chamber by the magnetic field generating means. Placed in
[0017]
Preferably, the electric field generating means may be configured to have a circular, polygonal or elliptical axial symmetry having the same shape as the surface of the workpiece.
[0018]
In one embodiment, the high-frequency electric field generating means may be composed of a pair of electrodes arranged to insert the formed magnetic neutral line. In that case, each electrode may be formed in a disk shape, a perforated disk shape, or an annular shape.
[0019]
In a device for achieving the second object of the present invention, a high-frequency electric field is applied to a magnetic neutral line in a tilt angle direction including a right angle to the magnetic neutral line to cause a magnetic neutral discharge plasma to be generated in a surrounding space including the magnetic neutral line. Is generated. Therefore, in this method, the direction of the applied high-frequency electric field is not parallel to the formed magnetic neutral line, but the direction in which the magnetic neutral line is inserted. There is no need to wind a high-frequency coil along the curved neutral line, which eliminates the need for the induction electric field to provide the space required for installing the high-frequency coil outside the closed neutral line. In addition to being able to use the space in the vertical and horizontal directions of the neutral wire, it is possible to be free from the presence of vacuum walls made of insulating materials such as ceramics, which are inevitable for applying an induction electric field from outside the vacuum vessel. Become. According to one embodiment, when the high-frequency electric field generating means includes a pair of electrodes arranged above and below by inserting a magnetic neutral line, a high-frequency electric field is applied between these electrodes. In the specification, it is defined as "capacitive electric field type".
[0020]
Alternatively, the electric field generating means may be formed to have a circular, polygonal or elliptical axial symmetry having the same shape as the surface of the object to be processed, and to apply a high-frequency electric field along the magnetic neutral line.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0022]
FIG. 1 shows an embodiment of a magnetic neutral ray discharge plasma processing apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a vacuum chamber, which includes a plasma generation unit 2 and a substrate processing unit 3. As shown, a cylindrical magnet having a first end having an N pole and a second end having an S pole along the axis of the vacuum chamber is provided outside the plasma generating portion 2 of the vacuum chamber 1 as shown in the drawing. A constant current coil 5 is provided outside the cylindrical magnet 4 and coaxially with the cylindrical magnet 4. The constant current coil 5 is connected to a constant current power supply 7 via a current setting circuit 6. The cylindrical magnet 4 and the constant current coil 5 generate a magnetic neutral line 8 formed by a series of zero magnetic field positions that are continuously present in the plasma generation unit 2 of the vacuum chamber 1. By changing the value of the current flowing through the constant current coil 5 by the current setting circuit 6, the diameter of the annular magnetic neutral wire 8 formed by the cylindrical magnet 4 and the constant current coil 5 can be arbitrarily set. ing.
[0023]
By the way, although not shown in FIG. 1, naturally, a high-frequency electric field is applied to the magnetic neutral line 8 generated in the plasma generating unit 2 of the vacuum chamber 1 to discharge the magnetic neutral line 8 to the space including the magnetic neutral line 8. An electric field generating means for generating plasma is provided. As the electric field generating means, for example, an induction type electric field as shown in FIG. 6 can be employed. In that case, it can be arranged as a high-frequency antenna coil inside the cylindrical magnet 4.
[0024]
FIG. 2 shows another embodiment of the magnetic neutral ray discharge plasma processing apparatus according to the present invention. In this example, a capacitive electric field generating means for applying a high-frequency electric field to the magnetic neutral line to generate discharge plasma in a space including the magnetic neutral line is used.
[0025]
Also in this case, as in the case of FIG. 1, the vacuum chamber 1 includes a plasma generation unit 2 and a substrate processing unit 3. As shown, a cylindrical magnet having a first end having an N pole and a second end having an S pole along the axis of the vacuum chamber is provided outside the plasma generating portion 2 of the vacuum chamber 1 as shown in the drawing. A constant current coil 5 is provided outside the cylindrical magnet 4 and coaxially with the cylindrical magnet 4. The constant current coil 5 is connected to a constant current power supply 7 via a current setting circuit 6. The cylindrical magnet 4 and the constant current coil 5 generate a magnetic neutral line 8 formed by a series of zero magnetic field positions that are continuously present in the plasma generation unit 2 of the vacuum chamber 1. By changing the value of the current flowing through the constant current coil 5 by the current setting circuit 6, the diameter of the annular magnetic neutral wire 8 formed by the cylindrical magnet 4 and the constant current coil 5 can be arbitrarily set. ing.
[0026]
Further, a pair of electrodes 9 and 10 are arranged at positions vertically sandwiching the magnetic neutral line 8 in the plasma generating section 2 of the vacuum chamber 1, and these electrodes 9 and 10 are perpendicular to the magnetic neutral line 8. Depending on the application of the device, it is adapted to apply a high-frequency electric field and is configured as a disk as shown in FIG. 3 or a ring as shown in FIG. 4, or a perforated disk as shown in FIG. . In this case, the outer shape is circular in the illustrated examples, but the outer shape or the outline can be formed into a polygon or an ellipse depending on the application of the apparatus.
[0027]
A pair of electrodes 9 and 10 arranged in the plasma generation unit 2 of the vacuum chamber 1 are connected to high-frequency power supplies 11 and 12, respectively, so that a high-frequency electric field is applied between these electrodes. In such a “capacitive electric field type”, if a DC component is included in the high-frequency discharge, dielectric breakdown between the upper and lower electrodes 9 and 10 may be caused, which may lead to equipment damage. Therefore, in the present invention, in order to prevent such a situation, each of the electrodes 9 and 10 is covered with an insulator as indicated by reference numeral 13 in the drawing. Further, the shape of each of the electrodes 9 and 10 varies depending on the content of the processing technology, and a disk-shaped one is selected in CVD or the like, and the shape required for the third surface such as a target for sputtering is used. Can be selected to create a spray path from the substrate to be processed.
[0028]
In the illustrated example, the electrodes 9 and 10 are vertically arranged in parallel with a plane including the magnetic neutral line 8 generated in the plasma generation unit 2 of the vacuum chamber 1. The magnetic neutral line 8 may be arranged so as to apply a high-frequency electric field to the magnetic neutral line 8 in the inclination angle direction.
[0029]
【The invention's effect】
As described above, according to the present invention, a magnetic field generating means for generating a magnetic neutral line formed by a series of positions of zero magnetic field continuously present in a vacuum chamber, and a magnetic field generating means for generating a magnetic neutral line in the vacuum chamber Means for generating a discharge plasma in a space containing the magnetic neutral line by applying a high-frequency electric field to the magnetic neutral line to be processed, and processing the workpiece using the plasma in the vacuum chamber In the discharge plasma processing apparatus, the magnetic field generating means includes a cylindrical magnet having a first end having an N pole and a second end having an S pole along the axis of the apparatus, and a cylindrical magnet provided outside the cylindrical magnet. Since it is constituted by a constant current coil provided coaxially, the weight and weight of the device can be reduced, and the effect of assembling and maintaining the device can be obtained easily.
[0030]
In addition, the electric field generating means for generating a discharge plasma in a space including the magnetic neutral line by applying a high-frequency electric field to the magnetic neutral line is formed at a right angle to the magnetic neutral line generated in the vacuum chamber by the magnetic field generating means. When placed in the vacuum chamber so as to apply a high-frequency electric field in the direction of the included tilt angle, it is not necessary to wind a high-frequency coil along a closed neutral line outside the vacuum chamber, which means that the vacuum chamber is insulated. Metal such as impermeable steel can be used without using a body wall, and the cost of the device can be reduced. As a result, the application range of the discharge plasma device can be improved and expanded.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view showing a configuration of an embodiment of a magnetic neutral ray discharge plasma processing apparatus according to the present invention.
FIG. 2 is a schematic longitudinal sectional view showing the configuration of another embodiment of the magnetic neutral ray discharge plasma processing apparatus according to the present invention.
FIG. 3 is a schematic perspective view showing a disk-shaped electrode constituting an electric field generating means used in the magnetic neutral ray discharge plasma processing apparatus shown in FIG.
FIG. 4 is a schematic perspective view showing an annular electrode constituting an electric field generating means used in the magnetic neutral ray discharge plasma processing apparatus shown in FIG.
FIG. 5 is a schematic perspective view showing a perforated disk-shaped electrode constituting an electric field generating means in the magnetic neutral ray discharge plasma processing apparatus shown in FIG. 2;
FIG. 6 is a schematic longitudinal sectional view showing an example of the configuration of a conventional induction electric field type circular magnetic neutral beam discharge plasma processing apparatus.
[Explanation of symbols]
1: vacuum chamber 2: plasma generation unit 3: substrate processing unit 4: cylindrical magnet 5: constant current coil 6: current setting circuit 7: constant current power supply 8: magnetic neutral wire 9: electrode 10: electrode 11: high frequency power supply 12: High frequency power supply 13: Insulator

Claims (12)

A magnetic field generating means for generating a magnetic neutral line formed by a series of zero magnetic fields continuously present in the vacuum chamber, and applying a high-frequency electric field to the magnetic neutral line generated in the vacuum chamber An electric field generating means for generating a discharge plasma in a space containing a magnetic neutral line, and a plasma processing apparatus for processing an object to be processed using plasma in a vacuum chamber. And a constant current coil provided coaxially with the cylindrical magnet outside the cylindrical magnet so that the first end has an N-pole and the second end has an S-pole. Wherein the diameter of the annular magnetic neutral wire formed by the cylindrical magnet and the constant current coil can be arbitrarily set by changing the value of the current supplied to the magnetic neutral wire discharge plasma processing apparatus. 2. The magnetic neutral ray discharge plasma processing apparatus according to claim 1, wherein the magnetic field generating means is configured to have a circular, polygonal, or elliptical axial symmetry having the same shape as the surface of the workpiece. 2. The magnetic neutral ray discharge plasma processing apparatus according to claim 1, wherein the magnetic field generating means is constituted by a direct current. 2. The magnetic neutral discharge plasma processing apparatus according to claim 1, wherein the magnetic field generating means is constituted by an alternating current including a commercial frequency. 2. The magnetic neutral discharge plasma processing apparatus according to claim 1, wherein the magnetic field generating means is configured by combining a direct current and an alternating current including a commercial frequency. The electric field generating means is arranged in the vacuum chamber so as to apply a high frequency electric field in a tilt angle direction including a right angle with a magnetic neutral line generated in the vacuum chamber by the magnetic field generating means. The magnetic neutral ray discharge plasma processing apparatus as described in the above. 7. The magnetic neutral ray discharge plasma processing apparatus according to claim 6, wherein the electric field generating means is configured to have a circular, polygonal or elliptical axial symmetry having the same shape as the surface of the workpiece. 7. The magnetic neutral ray discharge plasma processing apparatus according to claim 6, wherein the high-frequency electric field generating means includes a pair of electrodes arranged to insert the formed magnetic neutral line. 9. The magnetic neutral beam discharge plasma processing apparatus according to claim 8, wherein each electrode has a disk shape. 9. The magnetic neutral line discharge plasma processing apparatus according to claim 8, wherein each electrode is in the shape of a perforated disk. 9. The magnetic neutral discharge plasma processing apparatus according to claim 8, wherein each electrode is annular. The magnetic field according to claim 1, wherein the electric field generating means is configured to have a circular, polygonal, or elliptical axial symmetry having the same shape as the surface of the object to be processed, and applies a high-frequency electric field along a magnetic neutral line. Neutral discharge plasma processing equipment.

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