JPH10125495A - Phase control multi-electrode type alternating current discharge device using electrode placed in control - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a cooling efficiency of an electrode, enlarge an area for electric discharge, and make easy the use of a magnet by inventing a shape and an arrangement of a phase control multi-electrode type alternating current discharge electrode which is divided into plural electrode pieces for applying a phase control polyphase alternating current voltage. SOLUTION: Six pieces of divided electrodes 2 having a circular arc shape in section are arranged circumferenctially with a few gaps 2a formed between the pieces in a longitudinal direction, and are fixed in a close contact with the inner wall of a cylindrical vacuum chamber 4 through an insulating sheet 3. The vacuum chamber 4 forms a water cooled double tube and cools the sic pieces of divided electrodes 2 placed in contact with the inner wall of the vacuum chamber 4 by supplying cooling water 5 in the tube. The six pieces of bar-shaped magnets 6 disposed with the adjacent polarities reversed to each other placed in close contact with an outer wall of the vacuum chamber 4 along the gaps 2a, and besides the outer circumference is covered with a magnetic shield pipe 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new discharge device for efficiently and stably generating high-density, large-capacity weakly ionized low-temperature plasma.

[0002]

In a weakly ionized low-temperature plasma under a low gas pressure, a neutral gas temperature of about room temperature requires that various materials be treated with plasma without causing thermal deformation and deterioration. Is made possible. This feature
It is very useful for treating heat-sensitive materials such as fibers and plastics, and for forming a film on the surface.

In these film forming techniques utilizing low-temperature plasma, high-density low-temperature plasma occupies an important position. If high-density plasma can be obtained, discharge can be maintained under a lower pressure, and the quality of various films can be improved, the deposition rate can be improved, and the like.

Therefore, conventionally, a magnetic field has been separately applied in order to increase the density of low-temperature plasma as seen in a magnetron discharge device. The magnetron discharge device is intended to increase the probability of collision with gas atoms and improve ionization efficiency by applying a magnetic field perpendicular to the electric field, thereby improving the ionization efficiency. To maintain the discharge, thereby realizing high-speed and low-temperature film formation.

The shape and arrangement of electrodes for generating low-temperature plasma in conventional discharge devices, including this magnetron discharge device, vary depending on the requirements of the application object. It was common to arrange them linearly.

These electrodes have a low cooling efficiency due to their shape and arrangement, and are not cooled so much that large power cannot be applied. Since the discharge area is small, a high-density plasma can be uniformly formed between the electrodes over a wide range. Was difficult to generate.

In the case of a magnetron discharge device, it is necessary to cool the magnet attached to the electrode so that the temperature of the magnet is kept below the Curie temperature even if the electrode is heated by the discharge. In addition, moving the magnet to rotate the outer periphery of the circumferentially arranged electrodes or sliding behind the linearly arranged electrodes has the effect of making the plasma uniform. It was difficult to move the magnet by the mounting method.

Accordingly, the present invention provides a method of dividing a discharge electrode into a plurality of electrode pieces and applying a phase control multi-output AC voltage to improve the cooling efficiency of the electrode by devising the shape and arrangement of the phase control multi-electrode type AC discharge electrode. The purpose of the present invention is to increase the discharge area, increase the discharge area, and facilitate the use of magnets.

[0009]

In order to achieve the above object, the present invention is configured as follows.

That is, a plurality of electrode pieces are fixed to the inner wall of the discharge chamber in close contact with each other via a thin-film insulator, a cooling means for cooling the electrode pieces, and a multipolar magnetic field formed on the surface of the electrode pieces. And a multi-pole magnetic field forming means for confining a discharge by providing a multi-pole magnetic field forming means on the outer periphery of the discharge chamber, thereby supplying a multi-output AC power supply to each of the electrode pieces.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are a partial cross-sectional view (AA ′ plane in FIG. 2) and a partial longitudinal cross-sectional view (BB ′ plane in FIG. 1) of a cylindrical discharge device embodying the present invention. Show. In the discharge device 1, six pieces of segmented arc-shaped divided electrodes 2 are circumferentially arranged with a slight gap 2a in the vertical direction, and are described later on the inner wall of a cylindrical vacuum vessel 4 via an insulating sheet 3. Securely adhere by the method.

The vacuum vessel 4 forms a water-cooled double tube, and the cooling water 5 is supplied to cool the six pieces of divided electrodes 2 which are in close contact with the inner wall of the vacuum vessel 4. On the outer wall of the vacuum vessel 4, six adjacent bar-shaped magnets 6 arranged in reverse polarity are closely fixed along the gap 2 a, and the outer periphery thereof is covered with a cylindrical magnetic shield tube 7.

To the six divided electrodes 2, six AC power supplies (not shown) whose phases are shifted by ６ cycle and whose amplitudes are the same are supplied via a power supply line (not shown) to a method described later. Connect with.

The discharge device of the present invention has the above-described configuration,
The inside of the vacuum vessel 4 is evacuated by an exhaust device (not shown), and a discharge electric energy is supplied by supplying a polyphase alternating current of 1 kW or less to the six divided electrodes 2. As a result, FIG.
As shown in (1), a stable AC glow discharge is generated along the inner wall of the vacuum container 4.

FIG. 3 shows a state of magnetic field lines and discharge (plasma) confinement in a partial cross section (AA 'plane in FIG. 2) of the cylindrical discharge device of the present invention. The straight lines with arrows and the symbols indicating the vertical direction in the figure represent the directions of the magnetic field in the circumferential direction and the electric field in the radial direction in the vicinity of the center of the split electrode 2, and a
Represents a discharge (plasma) region. Since the polarities of the adjacent magnets 6 are opposite, the lines of magnetic force can cover the divided electrodes 2. Therefore, the discharge is confined in the central portion near the surface of each divided electrode 2. The direction of the AC electric field in the vicinity of the divided electrode 2 is in the positive or negative direction (radial direction) substantially perpendicular to the surface of the divided electrode 2 because the potential difference between the divided electrode 2 and the divided electrode 2 located on the opposite side is the largest.

FIGS. 4 and 5 show a partial cross-sectional view (AA 'of FIG. 5) of a prismatic discharge device as another embodiment of the present invention.
4) and a partial longitudinal sectional view (BB ′ plane in FIG. 4). In the discharge device 1, four flat plate-shaped divided electrodes 2 are arranged on two opposing surfaces (electrode surfaces) of an inner wall of a rectangular cylindrical vacuum vessel 4 with a slight gap 2a therebetween, and are linearly arranged in a vertical direction. Then, it is fixed to the inner wall of the vacuum vessel 4 through the insulating sheet (layer) 3 by a method described later.

The electrode surface of the vacuum vessel 4 forms a water-cooled double wall, and cooling water 5 is supplied to cool the four divided electrodes 2 which are in close contact with the inner wall of the vacuum vessel 4. On the outer wall of the electrode surface of the vacuum vessel 4, adjacent 5
The bar-shaped magnet 6 is fixed in close contact with both ends of the electrode surface along the gap 2a, and the outside thereof is covered with a magnetic shield plate 7.

Eight AC power supplies (not shown) whose phases are shifted by ８ cycle and have the same amplitude are supplied to the eight pieces of divided electrodes 2 via a feeder line (not shown). Connect with.

The prismatic discharge device of the present invention has the above-described structure, and the inside of the vacuum vessel 4 is evacuated by an exhaust device (not shown) to supply a polyphase alternating current of 1 kW or less to the eight divided electrodes 2. To supply discharge electrical energy. Thereby, a stable AC glow discharge is generated along the inner wall of the vacuum vessel 4 as shown in FIG.

FIG. 6 shows a state of magnetic field lines and discharge (plasma) confinement in a partial cross section (AA 'plane in FIG. 5) of the rectangular cylindrical discharge device of the present invention. The straight lines with arrows and the symbols indicating the up and down directions in the figure represent the directions of the magnetic field and the electric field in the vicinity of the center of the split electrode 2, and a represents discharge (plasma).
Represents an area. Since the polarities of the adjacent magnets 6 are opposite, the lines of magnetic force can cover the divided electrodes 2. Therefore, the discharge is confined in the central portion near the surface of each divided electrode 2. The direction of the AC electric field in the vicinity of the divided electrode 2 is in the positive or negative direction (X direction) substantially perpendicular to the surface of the divided electrode 2 because the potential difference between the divided electrode 2 and the opposite electrode is the largest.

Hereinafter, the shape and arrangement of the divided electrodes 2 according to the application of the discharge device will be described. FIG. 7 shows various examples of the shape of the divided electrode 2. FIG. 5A shows a thin plate-shaped divided electrode 2 having good heat radiation efficiency, and is effective in minimizing the heating of the electrode due to discharge. FIG.
A cylindrical split electrode 2 cut on one side by a plane parallel to the axis
This is effective when the discharge area of the electrode is increased or when the discharge between adjacent electrodes is actively used. Figure (c)
Is a divided electrode 2 having a large number of small projections formed on the surface. Since the electric field concentrates on the tips of the small projections, it is effective under conditions where discharge is unlikely to occur, for example, when the atmospheric gas pressure is considerably low or high. is there.

FIG. 8 shows various arrangement examples of the divided electrodes 2. FIG. 5A shows an example in which thin plate-like divided electrodes 2 of the same shape are arranged at equal intervals. Since discharge and plasma generation are performed in the same manner in each electrode, it is effective when the electrodes are arranged in a circumferential shape. It is. In this case, a uniform discharge is generated from the circumferential direction toward the center. FIG. 2B shows an example in which thin plate-like divided electrodes 2 of the same shape are arranged at unequal intervals. Both ends are dense and the center is sparsely arranged. Since plasma generation becomes active in a portion where electrodes are densely arranged, it is effective when the electrodes are arranged in a plane. In this case, since the plasma density at both ends is higher than when arranged at equal intervals, the plasma is uniformly distributed on a plane.

Hereinafter, a method of fixing the divided electrode 2 in close contact with the inner wall of the vacuum vessel 4 will be described. The first of the adhesion methods is a method using an adhesive. In this method, the insulating sheet 3 is attached to the inner wall of the vacuum container 4 using an adhesive, and then the divided electrodes 2 are attached to the insulating sheet 3 using an adhesive. This method has the advantage that it is easy to manufacture, but it does not have a high heat-resistant temperature of the adhesive, emits gas under reduced pressure or high temperature, and is difficult to peel off. However, there is a drawback in that even if a problem occurs, the entire device must be replaced.

Instead of directly attaching the insulating sheet 3 and the divided electrodes 2 to the inner wall of the vacuum vessel 4, the one once attached to a thin metal plate or the like serving as a base is pressed using a pressure contact ring or the like.
May be fixed in close contact with the inner wall. In this case, since the electrode portion can be attached and detached, the electrode portion can be exchanged according to the use if several sets having different numbers, shapes, arrangements, and the like of the electrodes are prepared.

The disadvantages of the method using the adhesive are that it is difficult to maintain the shape by applying a required pressure until the adhesive is hardened, and that the entire electrode section including these mechanical devices is placed in a thermostat. Must be raised to the solidification temperature of the adhesive.

As a specific example using an adhesive, a thickness of 0.3 m
m on SUS304 polished stainless steel base sheet,
A 0.8-mm-thick boron nitride insulating sheet with good thermal conductivity and electrical insulation is attached using a high-temperature curing type (150 ° C, 1 minute) epoxy adhesive with a heat resistance temperature of 350 ° C, and Then, a titanium electrode having a thickness of 0.3 mm and having a thickness of 100 m was adhered thereon by the same adhesive.
m, a cylindrical discharge device having a length of 500 mm.

The second of the contacting methods is a method by screwing. In this method, a screw hole or a mounting flange is prepared in advance on the inner wall of the vacuum vessel 4, and the divided electrodes 2 are screwed through an insulating sheet (layer) 3 and mechanically adhered and fixed. The advantage of this method is that if an insulating sheet with a high heat-resistant temperature is used, it can be used at a higher temperature than the method using an adhesive. Even if it deteriorates, it can be replaced by removing the screws. Disadvantages of this method are that if the number of screwed portions is small, the adhesion to the wall is not sufficient, and the number, shape, and arrangement of electrodes that can be mounted are limited by screw holes prepared in advance.

If the adhesion is not sufficient, the heat conduction from the electrode to the wall via the insulating sheet is reduced, and the cooling efficiency is reduced. In addition, gas enters between the wall, the insulating sheet, and the electrode, and it takes time to exhaust when discharging under reduced pressure.

An advantage of the screw set screw is to drill a hole along the axis of the screw to remove gas trapped when the screw is inserted into the screw hole.

As a specific example by screwing, a thickness of 0.8
6mm boron nitride insulation sheet and thickness 5mm
Each of the 6 divided graphite electrodes is overlapped to form a set of electrodes, and two Teflon rings having the same inner diameter as the inner wall of the apparatus are inserted into the upper and lower ends of the inner wall of the apparatus, and the inside of the Teflon ring is inserted. A cylindrical discharge device having an inner diameter of 100 mm and a length of 500 mm is formed by drilling and screwing a screw hole.

The third of the contacting methods is a method by thermal spraying. According to this method, alumina or ceramic is sprayed on the inner wall of the device to form a layer having a required electric insulation property, and then a conductive material such as titanium is sprayed thereon to form an electrode having an appropriate thickness. Form. Alternatively, a clay-like unsintered alumina ceramic is sprayed on the inner wall of the device to form an electrical insulating layer, and a conductive material such as clay-like titanium is sprayed thereon to form an electrode. It is placed in a heating furnace and subjected to heat melting (enamelling).

The advantages of the thermal spraying method are that the heat resistance temperature of the insulating layer is high, the degree of adhesion between the layers is high, heat conduction to the wall is large and the cooling efficiency is good, and almost no gas remains between the layers. And so on. The disadvantages of the thermal spray method are that when applying thermal spray to the inner wall or insulating layer of the device or enameling, a considerable heat load is applied to the entire device, and even if the characteristics of some insulating layers and electrodes deteriorate, And the whole must be replaced.

Hereinafter, a method for supplying a multi-phase alternating current to the divided electrodes 2 will be described. Since normal discharge is generated between two electrodes, two power supply lines (one power supply line when one electrode is grounded) may be introduced into the device and connected to the electrodes. . Split electrode 2 of discharge device of the present invention
Generates electric discharge between the multiple electrodes. Therefore, a large number of power supply lines must be introduced into the apparatus, and a multi-output AC power source whose phase is controlled (adjusted) must be connected to each divided electrode 2. As the number of power supply lines increases, it becomes more difficult to introduce power supply lines (bushings) inside the apparatus and connect them to respective electrodes while maintaining electrical insulation and vacuum tightness under reduced pressure. Therefore, an appropriate device for easily supplying power to the divided electrodes 2 is required.

FIG. 9 is a cross-sectional view of a device for supplying a multi-phase alternating current to the divided electrodes 2. The power supply device attaches the bushing 8 having the same number of outputs of the phase control power supply or a multiple thereof to the vacuum vessel 4 having both electrical insulation and vacuum tightness,
From there, the power supply line 9 is connected to each divided electrode 2.
Since the electrodes of the conventional discharge device are set apart from the inner wall of the device, a bushing is attached to an appropriate portion of the device, and a feeder line is connected from the bushing to the electrode. Since the divided electrodes 2 of the discharge device 1 of the present invention are in close contact with the inner wall of the vacuum vessel 4 via the thin insulating sheet 3, the feeder line 9 can be connected from the back surface of each divided electrode 2 through the bushing 8. is there.

That is, a bushing 8 having an insulating outer tube 8a formed of ceramic or the like and a conductive inner tube 8b formed of copper or the like is combined with a magnetic shield jacket 7, an outer wall of a vacuum vessel 4, cooling water 5, and a vacuum vessel 4. It penetrates through the inner wall and the wall surface of the discharge device 1 composed of the insulating sheet 3. Then, the power supply line 9 is connected to one end of the conductive inner tube 8b, and the other end of the conductive inner tube 8b is brought into contact with the back surface of the split electrode 2 to electrically connect the feed line 9 and the split electrode 2. At this time, the waterproof and airtight properties of the outer and inner walls of the vacuum container 4 are maintained. Further, the electrical insulation of the conductive inner tube 8b when penetrating the insulating sheet 3 is maintained.

The method of connecting the conductive inner tube 8b to the divided electrode 2 differs depending on the method of fixing the divided electrode 2 in close contact with the inner wall of the vacuum vessel 4. In the method using an adhesive, a male screw is formed on the tip of the conductive inner tube 8b, a screw hole is made on the back surface of the divided electrode 2, and the tip of the conductive inner tube 8b is screwed into the hole to connect. At this time, the gap between the screw and the screw hole is sealed with an adhesive.

In the method by screwing, as will be described later, a female screw is formed on the tip of the conductive inner tube 8b to which the power supply line 9 is connected, and the divided electrode 2 is evacuated with the screw from the front surface. The container 4 is fixed in close contact with the inner wall. Thus, power is supplied to the divided electrode 2 and the divided electrode 2 is fixed to the inner wall of the vacuum vessel 4 with one screw.

In the thermal spraying method, the bushing 8 is attached to the vacuum vessel 4 before thermal spraying. Then, an insulating layer is sprayed on the inner wall of the vacuum vessel 4, and thereafter,
The insulating outer tube 8a of the bushing 8 protruding from the inner wall of the vacuum vessel 4 is removed to expose the conductive inner tube 8b, and the conductive split electrode 2 is sprayed on this. Thereby, the split electrode 2
And the conductive inner tube 8b are electrically connected.

The above method has a practical advantage that the internal wiring can be omitted as compared with a case where the power supply line 9 is once introduced into the vacuum vessel 4 and connected to each of the divided electrodes 2 using a multi-core bushing or the like. . This effect is greater as the number of electrodes and the number of wirings are larger.

FIGS. 10, 11 and 12 show a cylindrical discharge device 1 for feeding the divided electrode 2 by screwing and fixing the upper end thereof. FIG. 10 shows the upper flange 1 of the device.
FIG. 11A is a cross-sectional view (AA ′ plane in FIG. 11) of FIG.
3 is a vertical sectional view of the vacuum container 4. FIG. FIG. 12 shows a lower flange 1 for fixing the lower end of the divided electrode 2 by screwing.
FIG. 12 is a cross-sectional view of FIG. The upper flange 1a is formed of a heat-resistant insulating material (Teflon, ceramic, or the like), and a radial bushing 8 penetrates toward each of the divided electrodes 2 which is in close contact with the inner wall of the vacuum vessel 4 while maintaining vacuum tightness.

The upper flange 1a and the lower flange 1b are
It is attached to the upper end and the lower end of the vacuum vessel 4 while maintaining the vacuum tightness by an O-ring (not shown). At this time,
Upper flange 1a, vacuum vessel 4 and lower flange 1b
Of the bushing 8 is not exactly protruded inward.

A female screw 8 is provided at the end of the bushing 8 on the inner wall side.
The upper end of the divided electrode 2 is fixed to the inner wall of the upper flange 1a with the insulating sheet 3 interposed therebetween. Here, since the outer wall end of the bushing 8 extends to the outer periphery of the upper flange 1a, if the power supply line 9 is connected to the conductive inner tube 8b exposed at the outer wall end of the bushing 8, the divided electrode 2 and the power supply are connected. The electric wires 9 are electrically connected.

The split electrode 2 is not fixed directly to the inner wall of the vacuum vessel 4 with screws, but is fixed at its upper end and lower end to the inner walls of the upper flange 1a and the lower flange 1b with screws 10, respectively. At this time, since the inner diameters of the upper flange 1a, the lower flange 1b, and the vacuum vessel 4 are the same, the split electrode 2 is in close contact with the inner wall of the vacuum vessel 4 via the insulating sheet 3.

The lower flange 1b is made of a heat-resistant insulating material, has the same inner diameter as the vacuum vessel 4, seals the lower end of the vacuum vessel 4, and inscribes a movable ring 11 at the center. The screw holes of the screws 10 for attaching the divided electrodes 2 are radially arranged on the inner wall of the eleventh electrode 11. When the divided electrode 2 expands in the movable ring 11 due to heat generated by discharge and extends in the length direction, the movable ring 11 descends and can absorb this expansion.

The lower flange 1b located on the outer periphery of the movable ring 11 is provided to secure a moving space for the movable ring 11 and to maintain vacuum tightness and electrical insulation of the outer periphery of the movable ring 11. The inside of the movable ring 11 is slightly larger.

FIG. 13 shows a screw 1 for attaching the split electrode 2.
0 shows a longitudinal sectional view. The screw 10 drills a hole along the axis of the screw 10 to remove gas left at the bottom of the screw hole when inserted into the female screw hole. Alternatively, screw 10
May be cut off in a plane parallel to the axis.

In an actual apparatus, a preliminary discharge chamber and a vacuum exhaust portion are mounted above and below the upper flange 1a and the lower flange 1b in FIG. In addition, a plurality of vacuum vessels 4
By connecting the upper flange 1a and the lower flange 1b, the applicable object can be lengthened.

FIGS. 14, 15 and 16 show the rectangular cylindrical discharge device 1 for supplying power to the divided electrode 2 and fixing the upper end by screwing. FIG. 14 is a cross-sectional view (AA ′ plane of FIG. 15) of the upper lid 1 a, and FIG. 15 is a vertical cross-sectional view of the vacuum vessel 4. FIG. 16 is a cross-sectional view of the lower lid 1b for fixing the lower end of the divided electrode 2 by screwing (B in FIG. 15).
−B ′ plane). The upper lid portion 1a is formed of a heat-resistant thick plate insulator, and each of the divided electrodes 2 is in close contact with the inner wall of the vacuum vessel 4.
The bushing 8 penetrates while maintaining vacuum tightness.

The upper lid 1a and the lower lid 1b are attached to the upper and lower ends of the vacuum vessel 4 while maintaining the vacuum tightness.
At this time, the inner wall surfaces of the upper lid portion 1a, the vacuum vessel 4 and the lower lid portion 1b are strictly located on the same plane, and the inner wall end of the bushing 8 is prevented from protruding inward.

A female screw 8 is provided at the end of the bushing 8 on the inner wall side.
The upper end of the split electrode 2 is fixed to the inner wall of the upper lid 1a with the insulating sheet 3 interposed therebetween. Here, since the outer wall end of the bushing 8 extends to the outside of the upper lid 1a, if the power supply line 9 is connected to the conductive inner tube 8b exposed at the outer wall end of the bushing 8, the divided electrode 2 and the power supply are connected. The electric wires 9 are electrically connected.

The divided electrode 2 is not directly fixed to the inner wall of the vacuum vessel 4 with a screw, and the upper end and the lower end are respectively formed on the upper lid 1.
a and the inner wall of the lower lid 1b with screws 10. At this time, since the upper lid portion 1a, the lower lid portion 1b, and the inner wall surface of the vacuum vessel 4 are on the same plane, the divided electrode 2 is in close contact with the inner wall of the vacuum vessel 4 via the insulating sheet 3.

The lower lid 1b is made of a heat-resistant insulating material,
The inner wall is on the same plane as the vacuum vessel 4, the lower end of the vacuum vessel 4 is sealed, the movable frame 12 is inscribed at the center, and the screw hole of the screw 10 for attaching each divided electrode 2 to the inner wall of the movable frame 12. Place. When the divided electrodes 2 expand in the movable frame 12 due to heat generated by electric discharge and extend in the length direction, the movable frame 12 is lowered and can absorb the extension.

The lower lid portion 1b located outside the movable frame 12 secures a space for moving the movable frame 12,
It is provided to maintain vacuum confidentiality and electric insulation on the outer periphery of the movable frame 12, and the inside of the movable frame 12 is made slightly larger.

In the following, a method of connecting the phase control multi-output AC power supply to the divided electrodes 2 and performing sputter coating using the electrodes themselves as targets by electric discharge to make the wear of each electrode spatially uniform as much as possible. explain.
As shown in FIG. 3 or FIG. 6, the discharge (plasma) region is confined to a part of a narrow region of each electrode by the multi-pole magnetic field, so that the electrode wear due to sputtering increases only in this region. When the wear in this area reaches the base of the electrode, the electrode must be replaced.In order to increase the utilization rate of the electrode as a target, the worn part of the electrode is moved and the entire electrode is worn as uniformly as possible. It is necessary to devise it.

In order to move the wear portion, that is, the discharge region, the distribution of the multipole magnetic field may be moved as is often done in a conventional magnetron sputtering apparatus. That is, a permanent magnet or a magnetic field generating coil for generating a multi-pole magnetic field is spatially moved to move a discharge location on the electrode surface, thereby making the wear on the electrode surface uniform. FIG. 17, FIG.
8 and FIG. 19 schematically show how to move the multipolar magnetic field in the case of the split electrode 2 of the discharge device 1 of the present invention. The magnetic field here is generated by the permanent magnet 6. FIG. 17 shows the split electrode 2
18 and FIG. 19 show the split electrode 2
Is a configuration of a multipolar magnetic field (lines of magnetic force) when there is a discharge (plasma) region at the left end and the right end. By moving the position of the permanent magnet 6 provided outside the vacuum vessel 4 to the left and right, the multipolar magnetic field configuration shifts, and the discharge (plasma) generation region on the surface of the divided electrode 2 moves. By appropriately adjusting this movement, the wear of the surface of the divided electrode 2 can be made uniform.

FIGS. 20 and 21 show a cross section of a mechanical mechanism for attaching a permanent magnet 6 for forming a multi-pole magnetic field to the outer wall of the vacuum vessel 4 and sliding reciprocally along the outer circumference of the vacuum vessel 4 in the cylindrical discharge device 1. A plan view and a longitudinal sectional view are shown. To facilitate sliding of the permanent magnet 6, a thin Teflon sheet is placed on the vacuum container 4
Six rod-shaped permanent magnets 6 attached to the outer wall and integrally attached to a magnetic shield tube 7 surrounding the outer periphery of the vacuum vessel 4 are brought into contact. A rack-shaped gear 13 is attached to the magnetic shield tube 7, and a circular gear 14 meshing with the rack 13 is rotated in the forward and reverse directions so that the permanent magnet 6 is reciprocated along the outer periphery of the vacuum vessel 4.

The following describes a method of generating a magnetic field the same as that of a permanent magnet by flowing a current through a coil, a method of moving a magnetic field by switching a current flowing through a plurality of coils, and a method of moving a magnetic field in a cylindrical discharge device. Method will be described. As shown in FIG. 22, consider a columnar micro-permanent magnet having a magnetization intensity M, a thickness in the magnetization direction dh, and an area vector dS. Current d that generates a magnetic field equivalent to this
i (direction and its magnitude) can be obtained from Equation 1 because the magnetic moments are equal in the two cases.

(Equation 1) Here, * on the left side represents the inner product of the vectors. From Equation 1, the equivalent current becomes Equation 2, and the magnetization strength of the permanent magnet is
It can be seen that the direction and the magnetization direction are determined from the length of the magnet.

(Equation 2) Here, the direction in which the equivalent current flows is a direction in which the direction of the area vector dS and the direction of the magnetization vector M of the surface formed by surrounding the equivalent (circular) current along the flow are the same. The direction of the area vector is defined as the direction in which the right-handed screw advances when the right-handed screw is turned along the direction in which the current flows. In the case of FIG. 22, the equivalent current is a loop current flowing counterclockwise along the edge of the thickness dh of the columnar permanent magnet.

FIG. 23 shows a bar-shaped permanent magnet whose magnetization intensity is M, thickness in the direction of magnetization is h, and the area of the magnetized surface is S (= width w × length g). , An equivalent current i of magnetization. From Equation 2, the magnitude of the equivalent current is given by Equation 3, and the direction is the direction in which the direction of magnetization is the same as the area vector created by the equivalent current along the flow.

(Equation 3) That is, the equivalent current of the magnetization flows counterclockwise along the thickness h plane parallel to the direction of the magnetization, and the magnitude becomes the loop current of Formula 4.

(Equation 4)

FIGS. 24 and 25 are a perspective view and a cross-sectional view showing an actual winding method of an equivalent current coil for flowing an equivalent current of magnetization of the bar-shaped permanent magnet. In the equivalent current coil, the coil is wound along the surface where the equivalent current flows, and the current I flows in the same direction as the direction in which the equivalent current flows. At this time, when the number of turns of the coil is N, the value of I is represented by Expression 5.

(Equation 5)

FIGS. 26 and 27 show that the inner diameter is d1 and the outer diameter is d.
2. In the case of a cylindrical permanent magnet having a thickness of w, a magnetization direction of a radial direction, and a magnetization intensity of M, an equivalent current i of magnetization flowing counterclockwise on the front surface and flowing clockwise on the back surface. The equivalent currents i of the same magnitude of magnetization are shown. Here, it is assumed that the magnetization intensity is uniform regardless of the distance from the center, that is, the radius (actually, it is difficult to magnetize in this way). The equivalent current of magnetization is apparently
This is because the current component connecting the front and back surfaces is offset in the process of synthesizing the equivalent current of the magnetization for the minute portion of the cylindrical magnet as shown in FIG. It is.

Equivalent current i of magnetization in FIGS. 26 and 27
Is obtained from the equivalent current di for the minute portion in FIG. FIG. 28 shows a minute component of the cylindrical magnet in cylindrical coordinates with the origin at the center of the lower surface of the cylindrical magnet. By integrating in the radial and azimuth directions, the equivalent current of the entire magnetization is obtained. As shown in FIG. 28, the equivalent current in this minute portion is a loop current that reaches the front surface from the back surface through the side surface in the thickness direction, passes through the opposite side surface, and returns to the back surface again. Here, it can be seen that the current components flowing up and down on the side surface in the thickness direction cancel each other as the integration is performed in the azimuth direction. Therefore, as a result, only the loop current flowing in the azimuth direction in which the magnitude is the same and the directions are opposite to each other is left only on the front and back surfaces.

In FIG. 28, the value of the equivalent current of the magnetization at the radial position r is given by
Thus, Equation 7 is obtained. When both sides are integrated with r, Equation 8 is obtained, and an equivalent current of magnetization in FIGS. 26 and 27 is obtained.

(Equation 6)

(Equation 7)

(Equation 8)

FIGS. 29 and 30 are a perspective view and a cross-sectional view showing an actual winding of an equivalent current coil for flowing an equivalent current of magnetization of a cylindrical permanent magnet. Here, since the cylindrical magnetic field coil is divided into two and attached to the cylindrical discharge device, only one half of the coil is shown. The winding method of the coil is the same as the flow of the equivalent current of the minute portion shown in FIG. 28, the back surface is wound along the circumference from the inside, and when it reaches the end, it passes through the right section and the front surface becomes the circumference. Wrap along, pass the left section when it reaches the end, and return to the back again.
Repeat this winding process from the inside to the outside,
Wrap the coil all over the surface. When two half coils are completed, the two are combined into a cylindrical coil. At this time, the current in the section of the cross section is canceled because the directions of the current in this section of the two coils are opposite. Current I flowing in coil
Is given by Equation 9 where N is the number of turns of the coil.

(Equation 9)

FIG. 31 shows four current coils of the same standard as one.
A multi-pole magnetic field is shown as a set, in which several sets are arranged side by side while reversing the direction of current between adjacent sets. Here, the solid lines of magnetic force indicate the lines of magnetic force when current flows only through the first and second coils of each set. On the other hand, the broken lines of magnetic force indicate the lines of magnetic force when current flows only through the third and fourth coils of each set.

FIG. 32 shows the arrangement of magnets when a multi-pole magnetic field equivalent to that of FIG. 31 is formed using permanent magnets. Here, the lines of magnetic force and the layout shown by solid lines and broken lines correspond to the cases of lines of magnetic force shown by solid lines and broken lines in FIG. 31, respectively.

As shown in FIG. 31, by switching the current flowing through the coils from No. 1 and No. 2 to No. 3 and No. 4 in one set of coils, as shown in FIG. It can also be seen that the magnetic field can be moved.

In FIG. 31, the coil width is half the width w of the permanent magnet equivalent to this, but this causes the generated magnetic field to move as smoothly as possible when the current flowing through the coil is switched in order. That's why. As the number of coil divisions increases, the movement becomes smoother, but the configuration becomes complicated, and a power supply for coil excitation is required for the number of divisions.

FIG. 33 shows an example of time adjustment of the current flowing through four coils in one set when the magnetic field is moved as shown in FIG. However, it is assumed that the core of the coil is an air core or a non-magnetic material. When the core is a magnetic material, a hysteresis occurs in a magnetic field (magnetic flux density) generated in response to a change in current value, and therefore, it is necessary to perform current adjustment to correct the hysteresis.

In the current transition diagram of FIG. 33, the overall width of the coil to be simultaneously supplied with power is made as equal as possible to the width w of the permanent magnet of FIG. 32, and the magnetic field generated by the coil current is changed from left to right. Then, the discharge time to each coil is adjusted again so as to move spatially as uniformly as possible from right to left.

In the state of the coil current at times t = t1 and t = t2 in FIG. 33, the magnetic fields indicated by the solid lines and the broken lines of magnetic force in FIG. 31 are formed, respectively.

In FIG. 34, in a cylindrical discharge device having six divided wall-contact electrodes 2, six coil groups, each of which is composed of six coils, are attached to the outer periphery of the device, and the current flowing through the coils is determined. Are sequentially switched to move the multipole magnetic field in the circumferential direction. A magnetic field equivalent to a permanent magnet is generated by two coils of which width is half w / 2, and a group of six coils is arranged in a circumferential direction so as to generate a magnetic field equivalent to a multipole magnetic field distribution. Place and coordinate the power supply to them. The reason why the coil width is reduced to half is that the magnetic field can move as smoothly as possible in the circumferential direction.

The magnetic field lines in FIG. 34 indicate the magnetic field lines of the multi-pole magnetic field generated when a current is applied to only the third and fourth coils in the six coil groups.

FIG. 35 shows the arrangement of all coils when the device is deployed in the circumferential direction. Here, the arrow indicates the direction of the current flowing through the coil. The upper and lower coils are for improving confinement of discharge (plasma) at the upper and lower ends of the device. This coil does not need to move the generated magnetic field, so that the coil width is made the same as the width of the permanent magnet, and an equivalent current of magnetization corresponding to the permanent magnet flows through the coil.

The six coil groups attached to the side wall are arranged at equal intervals in the circumferential direction, and currents in opposite directions flow in adjacent sets. In each set of coil groups, adjustment is made so that current flows simultaneously only to two coils sequentially from the end.

FIG. 36 shows an example of time adjustment of the current flowing through six coils in one set when the magnetic field is moved with time in the positive and negative circumferential directions. However, it is assumed that the winding core of the coil is an air core or a non-magnetic material. Further, the magnetic field generated by the coil current is spatially changed from left to right, and again from right to left, so that the overall width of the simultaneously operating coil is as close as possible to the width w of the permanent magnet in FIG. The power supply time to each coil is adjusted so as to move as uniformly as possible. The magnetic field indicated by the magnetic field lines in FIG. 34 is generated in the coil current state at times t = t1 and t = t2.

[0077]

According to the discharge electrode of the present invention, a plurality of electrode pieces are fixed to the inner wall of the discharge chamber with a thin-film insulator interposed therebetween. Therefore, according to the present invention, since the electrode is in close contact with the inner wall of the discharge chamber, the discharge area can be set to approximately the same size as the discharge chamber capacity, and the utilization efficiency of the apparatus space can be maximized. Further, by cooling the wall surface having a large capacity from the outside, heat generated in the electrodes can be efficiently and easily removed. For this reason, a large electric power can be supplied to the small electrode, and it is not necessary to bring the cooling device into the inside of the device, so that the configuration of the entire device can be made simple and compact. Further, since the distance between the electrode and the outer wall of the device is short, a permanent magnet or an electromagnetic coil can be attached to the outer wall of the device, and a magnetic field can be easily applied near the electrode. Therefore, there is no need to bring a permanent magnet or an electromagnetic coil with a cooling device into the device, so that a magnetic field can be generated with a simple device configuration and the movement of the magnetic field can be easily performed by mechanical or electrical means. It can be carried out.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a cylindrical discharge device of the present invention.

FIG. 2 is a longitudinal sectional view of the cylindrical discharge device of the present invention.

FIG. 3 is a diagram showing lines of magnetic force and a state of electric discharge of the cylindrical electric discharge device.

FIG. 4 is a cross-sectional view of the prismatic discharge device of the present invention.

FIG. 5 is a longitudinal sectional view of the rectangular discharge device of the present invention.

FIG. 6 is a diagram showing lines of magnetic force and a state of electric discharge of the rectangular cylindrical discharge device.

FIG. 7 is a diagram showing an example of the shape of an electrode.

FIG. 8 is a diagram showing an example of the arrangement of electrodes.

FIG. 9 is a cross-sectional view of a device that supplies polyphase alternating current to electrodes.

FIG. 10 is a cross-sectional view of an upper flange of the cylindrical discharge device.

FIG. 11 is a longitudinal sectional view of a vacuum vessel of the cylindrical discharge device.

FIG. 12 is a cross-sectional view of a lower flange of the cylindrical discharge device.

FIG. 13 is a longitudinal sectional view of a screw for attaching an electrode.

FIG. 14 is a cross-sectional view of the upper lid of the rectangular cylindrical discharge device.

FIG. 15 is a vertical cross-sectional view of a vacuum vessel of the prismatic discharge device.

FIG. 16 is a cross-sectional view of a lower lid portion of the prismatic discharge device.

FIG. 17 is a diagram showing a multipolar magnetic field configuration in which a discharge region is at the center of an electrode.

FIG. 18 is a diagram showing a multipolar magnetic field configuration in which a discharge region is moved to the left end of an electrode.

FIG. 19 is a diagram showing a multipolar magnetic field configuration in which a discharge region is moved to the right end of an electrode.

FIG. 20 is a cross-sectional view of a mechanical mechanism for moving a permanent magnet of the cylindrical discharge device.

FIG. 21 is a longitudinal sectional view of a mechanical mechanism for moving a permanent magnet of the cylindrical discharge device.

FIG. 22 is a schematic diagram showing an equivalent current of a columnar permanent magnet.

FIG. 23 is a schematic diagram showing an equivalent current of a bar-shaped permanent magnet.

FIG. 24 is a perspective view showing an actual winding method of the rod-shaped equivalent current coil.

FIG. 25 is a cross-sectional view showing an actual winding method of the rod-shaped equivalent current coil.

FIG. 26 is a schematic diagram showing an equivalent current on the surface of a cylindrical permanent magnet.

FIG. 27 is a schematic diagram showing an equivalent current on the back surface of the cylindrical permanent magnet.

FIG. 28 is a schematic diagram showing an equivalent current in a minute cylindrical magnetization portion.

FIG. 29 is a perspective view showing an actual winding method of the cylindrical equivalent current coil.

FIG. 30 is a cross-sectional view showing an actual winding method of the cylindrical equivalent current coil.

FIG. 31 is a schematic diagram showing an arrangement of coils and movement of a magnetic field due to current adjustment.

FIG. 32 is a schematic view showing the movement of a magnetic field due to an equivalent permanent magnet and mechanical movement.

FIG. 33: Time adjustment of coil current for magnetic field movement (4
FIG.

FIG. 34 is a schematic diagram showing an example of the arrangement of multipole magnetic field configuration coils in a cylindrical discharge device.

FIG. 35 is a schematic diagram showing an arrangement example of a multi-pole magnetic field configuration coil developed in a circumferential direction.

FIG. 36: Time adjustment of coil current for magnetic field movement (6
FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge device 2 Split electrode 3 Insulating sheet 4 Vacuum container 5 Cooling water 6 Magnet 7 Magnetic shield 8 Bushing 9 Feeding line 10 Screw 11 Movable ring 12 Movable frame 13 Rack-shaped gear 14 Circular gear

Claims (1)

[Claims] 1. A plurality of electrode pieces are fixed to an inner wall of a discharge chamber in close contact with each other via a thin-film insulator, a cooling means for cooling the electrode pieces, and a multipolar magnetic field formed on a surface of the electrode pieces. And a multi-pole magnetic field forming means for confining a discharge by providing a multi-pole magnetic field forming means on the outer periphery of the discharge chamber, and supplying a phase control multi-output AC power to each of the electrode pieces.