JP6872935B2 - Plasma generator - Google Patents

Description

The present invention relates to an inductively coupled plasma generator.

Plasma generators are used in various fields such as coating, microfabrication, surface modification, and contaminant removal. Capacitively Coupled Plasma (also known as electric field coupled type) and inductively coupled type (Inductively Coupled Plasma, also known as magnetic field coupled type) are known as plasma generators. In the capacitively coupled type, plasma is generated by directly applying a high-frequency electric field by an electrode provided in a chamber through which a material gas to be converted into plasma flows. In the inductive coupling type, for example, an elongated tubular chamber is passed through a magnetic core, and a high-frequency current is passed through an inductive coil wound around the magnetic core to generate a high-frequency magnetic field around the chamber. Plasma is generated by generating a high-frequency electric field of.

Patent Document 1 describes an inductively coupled plasma generator in which a high-frequency current is passed through a primary winding wound around a magnetic core provided so as to surround a part of an annular chamber to form an annular chamber. A configuration that generates a high-frequency electric field along the line is disclosed. The plasma generator of Patent Document 1 states that by making the annular chamber made of metal, it is possible to increase the resistance to chemical reactions and high temperatures caused by a specific material gas usually used for plasma treatment.

Japanese Patent No. 4070152

In a plasma generator, the chamber becomes very hot to generate plasma. A large current is required to generate high-energy plasma, and the need for cooling the chamber becomes a problem, but Patent Document 1 does not disclose it. Regarding the cooling method, if the size of the device is allowed to be increased, a large-scale cooling mechanism such as air cooling and water cooling can be realized as much as possible, but it is required to achieve both miniaturization of the device and high output.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a plasma generator that is provided with a cooling mechanism and realizes miniaturization of the entire device.

The plasma generator according to the present disclosure includes a chamber formed of a conductive material in an annular shape and a gas flow path for a material gas formed inside along the shape, and a high-frequency power source for supplying a high-frequency current to the chamber. The plasma generator is provided, and the chamber is in close contact with a main body portion in which a part of the ring shape is omitted and an outer surface of the main body portion, and heat from a cooling medium supplied from the outside is applied to the main body portion. Includes a cooling unit that communicates to.

As a result, in the plasma generator according to the present disclosure, the high-frequency current supplied from the high-frequency power source flows through the main body portion of the chamber, and the cooling medium is directly supplied from the outside by the cooling portion along the outer surface of the main body portion of the chamber. Since heat exchange with and is performed, it is possible to efficiently suppress the temperature rise of the chamber.

In the plasma generator according to the present disclosure, the cooling portion is made of a heat conductive plate that is closely fixed along the outer surface of the main body portion and a heat conductor that is fixed to the heat conductive plate and the cooling medium flows inside. Including the cooling pipe.

As a result, in the plasma generator according to the present disclosure, it is possible to suppress the temperature rise of the chamber at low cost by using the heat conductor plate closely fixed to the main body portion.

In the plasma generator according to the present disclosure, the outer surface of the main body portion has a flat surface, and the heat conductive plate is closely fixed to a part or all of the flat surface.

As a result, in the plasma generator according to the present disclosure, since the plate made of a heat conductor is closely fixed to the flat surface used by the main body portion, the temperature rise of the chamber can be suppressed at low cost.

In the plasma generator according to the present disclosure, the cooling unit includes a recess provided on the outer surface of the main body portion through which the cooling medium flows, and a lid covering the recess.

As a result, in the plasma generator according to the present disclosure, the main body portion is directly caused by flowing a cooling medium through a recess provided in the main body portion or a recess provided in a plate-shaped member having thermal conductivity fixed to the main body portion. Since it is cooled, the temperature of the chamber can be increased efficiently.

In the plasma generator according to the present disclosure, the main body portion of the chamber is made of a conductive material and has a rectangular vertical cross section, and a base material bent and molded into the same shape is provided with through holes passing through the centers of each side. The insulator is included, and an insulator having a cross-sectional shape corresponding to the cross-sectional shape of the split body is included, and the end faces of the two split bodies are opposed to each other. A spacer made of a conductor is interposed between the other end faces so as to form a square ring, and the heat conductive plate of the cooling portion is closely fixed along the outer surface over the two divided bodies. Includes only one heat conductive plate.

As a result, in the plasma generator according to the present disclosure, one heat conductive plate extending over the two divided bodies is provided in the cooling portion provided in the main body portion in which two divided bodies having the same shape are connected so as to sandwich the insulator and the spacer. By using it, it is possible to realize compactness of the device and improvement of cooling efficiency.

In the plasma generator according to the present disclosure, the cooling unit includes a member of a conductive material, further includes an annular magnetic core provided at one or a plurality of locations of the chamber, and the magnetic core is a cross-sectional view of the chamber and the chamber. It is provided so as to surround at least a part of the outside of the cooling unit.

As a result, in the plasma generator according to the present disclosure, the cooling portion is made of a conductive material and passes through the inside of the magnetic core. When the high frequency current from the high frequency power supply is supplied to the main body of the chamber, the cooling part also becomes a current path, but since the cooling part passes through the inside of the magnetic core, compared to the case where the cooling part does not pass inside the magnetic core. The leakage flux can be reduced and the inductance component can be increased.

Further, in the case of the plasma generator of the present disclosure, the high frequency current supplied from the high frequency power supply flows through the main body portion of the chamber, and the plasma current flows in the discharge space inside the main body portion. The paths are close and nearly coaxial. Therefore, the leakage flux can be reduced and the coupling force can be strengthened. Even if a high-frequency current is passed directly through the chamber in this way, it can be efficiently cooled by using a cooling unit along the outer surface of the main body of the chamber, so it is possible to suppress high temperature without using a large cooling mechanism. it can.

It is explanatory drawing which shows the outline of the plasma generator in Embodiment 1. FIG. It is a perspective view which shows the appearance of the chamber in Embodiment 1. FIG. It is an exploded perspective view of the chamber in Embodiment 1. FIG. It is a cross-sectional view of the chamber by line AB in FIG. It is a vertical sectional view of the chamber by the CD line in FIG. It is an external perspective view which shows the other structural example of a cooling part. It is an exploded perspective view of the chamber of another configuration example of a cooling part. It is a perspective view which shows the appearance of the chamber in Embodiment 2. FIG. It is an exploded perspective view of the chamber in Embodiment 2. FIG. It is a perspective view which shows the appearance of the chamber in Embodiment 3. FIG. It is a perspective view which shows the appearance of the chamber in Embodiment 3. FIG. FIG. 3 is an exploded perspective view of the chamber according to the third embodiment. It is a perspective view which shows an example of the arrangement mode of the magnetic core of the chamber in Embodiment 3. FIG.

The present invention will be specifically described with reference to the drawings showing the embodiments thereof.

(Embodiment 1)
FIG. 1 is an explanatory diagram showing an outline of the plasma generator 1 according to the first embodiment. The plasma generator 1 includes a chamber 2, a magnetic core 3, and a high-frequency power supply 4.

The outer shape of the chamber 2 in the plan view shown in FIG. 1 is substantially a square ring, the vertical cross section of the ring is rectangular over the entire circumference, and a circular hole is provided in the center. The chamber 2 includes a main body portion 20 having a missing portion (hatched portion in FIG. 1) in which a central portion on one side is cut off at an appropriate length, and an insulator interposed in the missing portion. The main body portion 20 is made of a metal material having excellent conductivity such as aluminum. The main body portion 20 may be made of another metal material such as copper or iron, and may be made of a material other than metal as long as it has appropriate strength and conductivity. The insulator is formed of an insulating material such as ceramics, and has the same vertical cross section as the main body portion 20. The holes provided in the main body portion 20 and the insulator form a continuous gas flow path 29 inside the chamber 2 over the entire circumference. The gas flow path 29 communicates with the outside by gas inlets and gas outlets formed at two opposite corners of the main body portion 20. In the gas flow path 29, as shown by IN and OUT in FIG. 1, the material gas supplied to the gas inlet is internally turned into plasma and flows so as to be sent from the gas outlet to the subsequent process.

The magnetic core 3 is an annular body made of a ferrite magnetic material. The magnetic core 3 is fitted to the outside of each of the four sides of the main body portion 20. The magnetic cores 3 are not indispensable, and the number of the magnetic cores 3 is not limited to four as shown in FIG. 1, and are appropriately designed according to the plasma generation situation.

The high-frequency power supply 4 is connected to the end on the gas inlet side of the ends of the main body 20 facing each other with the missing portion (insulator) in between. The end of the main body 20 on the gas outlet side is grounded. The current supplied from the high-frequency power supply 4 flows from the end on the gas inlet side to the end on the gas outlet side, as shown by the solid white arrow in FIG.

In the plasma generator 1 configured as described above, the high-frequency current supplied from the high-frequency power supply 4 flows in the circumferential direction (toroidal direction) of the main body portion of the chamber 2 and orbits the cross section of the ring of the main body portion 20 (poloidal). A high frequency magnetic field is generated along the direction). Since the magnetic core 3 is provided, leakage of magnetic flux is reduced. Then, due to the action of electromagnetic induction of the high-frequency magnetic field, as shown by the broken white arrow in FIG. 1, the direction is opposite to the above-mentioned high-frequency current flowing in the main body portion 20 in the circumferential direction along the shape of the main body portion 20. A high frequency electric field is generated in the gas flow path 29 in the chamber 2. The material gas supplied from the gas inlet into the gas flow path 29 is turned into plasma by this high-frequency electric field and sent out from the gas outlet. As described above, in the plasma generator 1, the high-frequency current flowing through the main body portion 20 of the chamber 2 is used as the exciting current, and the plasma current flows through the gas flow path 29 inside the main body portion 20 by inductively coupled. The paths of the high-frequency current and the plasma current flowing in the opposite directions are close to each other and are substantially coaxial, so that the leakage flux can be reduced and the coupling force can be strengthened.

Hereinafter, a specific configuration of the chamber 2 which can realize the miniaturization of the entire apparatus while further preventing the high temperature while having the structure for reducing the leakage flux will be described in detail. In the following description, of the plasma generator 1 shown in FIG. 1, the description of the magnetic core 3 is omitted.

FIG. 2 is a perspective view showing the appearance of the chamber 2 according to the first embodiment, FIG. 3 is an exploded perspective view of the chamber 2, and FIG. 4 is a cross-sectional view of the chamber 2 according to the line AB in FIG. FIG. 5 is a vertical cross-sectional view of the chamber 2 taken along the line CD in FIG.

The chamber 2 is configured such that the divided bodies 20a and 20b having the same shape are connected via an insulator 23 and a spacer 24 to form a square ring as a whole. The split bodies 20a and 20b are made of a metal material having excellent conductivity such as aluminum. The split bodies 20a and 20b have a rectangular vertical cross section and are bent-formed (in FIG. 2 and the like, an example of forming a U-shape is shown), and a circular shape passing through the center of each side. It has a structure in which a through hole in a cross section is formed, and a U-shaped corner portion (a portion indicated by a broken line in FIG. 4) is diagonally cut to expose the intersection of the through holes on each side. Further, a flange 28 for connection is integrally formed at one end of the divided bodies 20a and 20b. The size of the flange 28 is the same as the size of the vertical cross section of the split bodies 20a and 20b.

The insulator 23 and the spacer 24 are plates of equal thickness having the same outer shape as the cross-sectional outer shape of the separate bodies 20a and 20b, and a through hole having the same diameter as the hole of the separate bodies 20a and 20b is formed in the center of each. The hollow portions 231 and 241 are provided by the above. The insulator 23 and the spacer 24 have the same cross-sectional shape as the split bodies 20a and 20b. The insulator 23 is made of an insulating material having appropriate strength, such as ceramics. The spacer 24 is made of a metal material having excellent conductivity which is the same as or different from that of the split bodies 20a and 20b. The cross-sectional shapes of the insulator 23 and the spacer 24 may be corresponding shapes such that the hollow portions 231 and 241 communicate with the hollow portions of the split bodies 20a and 20b, respectively. It does not have to be the same shape. The insulator 23 and the spacer 24 do not have to have the same shape.

In the chamber 2, one end portion provided with a flange 28 of the split bodies 20a and 20b and the other end portion of each of the split bodies 20a and 20b face each other, and an insulator 23 and a spacer 24 are interposed between the facing end faces. , It is configured by being integrally connected by a plurality of fixing bolts 27 passed through the flange 28. Then, the excised portions of the divided bodies 20a and 20b are covered with the inlet port 21, the outlet port 22, and the two lid plates 25 to form a tubular shape. As a result, the chamber 2 is configured by providing a gas flow path 29 that is continuous in a tubular shape by the central hole of the split bodies 20a and 20b and the central hole of the insulator 23 and the spacer 24.

In this way, an insulator 23 is interposed between one end faces of the divided bodies 20a and 20b having the same shape, and a spacer 24 made of a conductor is interposed between the gaps between the other end faces, as shown in FIG. It is possible to easily manufacture an annular main body portion 20 in which such a part is omitted. By making the split bodies 20a and 20b the same shape, the manufacturing cost can be reduced. Further, the split bodies 20a and 20b can be easily handled by forming the shape so as to include a wide flat surface. If the split bodies 20a and 20b have the same shape and can be connected to form an annular shape (not limited to a square ring but also a polygonal ring such as a hexagonal ring or an octagonal ring, or a circular ring, an elliptical ring, etc.), this can be used. Not limited. The split bodies 20a and 20b can be connected in an annular shape as long as they are bent tubular members. For example, the split bodies 20a and 20b are not only U-shaped as in the examples shown in FIGS. It may be formed in the shape of. Furthermore, the cross-sectional outer shape is not limited to being square.

Further, in the chamber 2 of the first embodiment, as shown in FIG. 4, the tubular body 26 is internally fitted in the hollow portion 231 of the insulator 23 provided at the portion corresponding to the missing portion of the main body portion 20. Another tube body 26 is internally fitted in the hollow portion 241 of the spacer 24. The tubular body 26 is made of an insulating material having sufficient strength, and is sufficiently long compared to the lengths of the insulator 23 and the spacer 24. An O-ring 261 provided on the inner circumference near the end face in contact with the insulator 23 or the spacer 24 of each of the split bodies 20a and 20b is elastically contacted with the outer circumference of the tubular body 26, whereby the insulator 23 and the spacer 24 are in contact with each other. Maintains the airtightness of the connection part.

The lid plate 25 is a metal flat plate corresponding to the rectangles at the corners of the divided bodies 20a and 20b. A glass window 251 is provided in the center of one or both of the lid plates 25. The window 251 enables observation of the plasma generation state inside the gas flow path 29.

The inlet port 21 is formed by erection of a gas pipe 210 having a small diameter in the center of a metal flat plate corresponding to a rectangle at a corner portion of the body 20b, and a material gas can pass therethrough. The outlet port 22 is formed by erection of a large-diameter gas pipe 220 in the center of a metal flat plate corresponding to the rectangle at the corner of the body 20a, and the material gas can pass therethrough. As a result, the gas flow path 29 formed inside the divided bodies 20a and 20b communicates with the outside via the gas pipe 210 of the inlet port 21 and the gas pipe 220 of the outlet port 22.

The chamber 2 further includes a cooling unit 5. The cooling unit 5 includes a heat conductive plate 51 fixed in close contact with each other along the outer surfaces of the divided bodies 20a and 20b, and a cooling pipe 52 fixed on the heat conductive plate 51, respectively. Both the heat conductive plate 51 and the cooling pipe 52 are made of a material having excellent heat conductivity such as copper. The heat conductive plate 51 is formed, for example, in substantially the same shape as the L-shaped surface of the split bodies 20a and 20b. The cooling pipe 52 is piped so as to bend along the center line of each of the heat conductive plates 51. One end of each cooling pipe 52 is bent outward and extends to the outside of the split pieces 20a and 20b, respectively, and the extended end is connected to a cooling medium supply device (not shown) via a connector 53. There is. Further, the other end of each cooling pipe 52 is bent inward and extended to the inside of the divided bodies 20a and 20b, and the extended ends thereof are connected to each other by the connectors 53 and 53 and the connecting pipe 54. As a result, the cooling medium such as cooling water supplied from the supply device flows inside the cooling pipe 52 from the outer extension end of the cooling pipe 52 on the split body 20a side, and cools the split body 20b side via the connecting pipe 54. It flows into the pipe 52 and returns to the supply device or is drained from the outer extension end. As a result, the heat conductive plate 51 in contact with the cooling pipe 52 is cooled, and the temperature rise of the components 20a and 20b, which are heated by the heat conductive plate 51 due to the plasma conversion of the material gas, is suppressed. The connecting pipe 54 is preferably made of an insulator. Since the cooling unit 5 is configured to pass inside the inner circumference of the main body portion 20 composed of the divided bodies 20a and 20b of the chamber 2, a current also flows through the constituent members of the conductive material of the cooling unit 5. This is to prevent. The current flowing through the cooling unit 5 including the connecting pipe 54 passing through the inside of the main body portion 20 does not contribute to the generation and maintenance of plasma in the chamber 2, and the inductance component of the chamber 2 is reduced. By making the connecting pipe 54 made of an insulator, the cooling pipe 52 connected by the connecting pipe 54 and the connector 53, and the heat conductive plate 51 on the split body 20a side and the split body 20b side to which the cooling pipe 52 is closely fixed, respectively. It is avoided that a current path different from that of the divided bodies 20a and 20b is formed on the heat conductive plate 51 of the above.

Needless to say, the cooling pipe 52 on the side of the split body 20a and the cooling pipe 52 on the side of 20b may be composed of one bent pipe. Further, in the examples shown in FIGS. 2 to 5, one cooling pipe 52 is bent and piped on the center line of each of the heat conductive plates 51, but it may be piped so as to meander on the heat conductive plate 51. Alternatively, two or more cooling pipes 52 may be piped to one heat conductive plate 51. Further, the cooling unit 5 may not include the heat conductive plate 51, and the cooling pipe 52 may be directly fixed to the outer surfaces of the separate bodies 20a and 20b, respectively. In this case, the cooling pipe 52 may be configured to meander on the outer surface of the split pieces 20a, 20b to obtain many heat exchange opportunities, or a plurality of cooling pipes 52 may be used. .. Further, in the examples shown in FIGS. 2 and 3, the cooling unit 5 is provided only on one of the L-shaped surfaces of the divided bodies 20a and 20b, but may be provided on the other surface as well. Further, since the split bodies 20a and 20b shown in FIG. 2 have flat surfaces other than the L-shaped surface, the heat conductive plate (or the cooling pipe itself) is closely attached to these surfaces (outer surface and inner surface). It may be fixed and the cooling pipe to which the cooling medium is supplied may be fixed to the heat conductive plate. The heat conductive plate 51 constituting the cooling unit 5 may have a shape that can be aligned with the outer surfaces of the divided bodies 20a and 20b.

As described above, in the chamber 2 of the first embodiment, since the cooling unit 5 is directly fixed to the divided bodies 20a and 20b, the high temperature can be efficiently suppressed. In particular, the split bodies 20a and 20b have many flat surfaces because they have a rectangular cross section and are formed in a U shape. On the flat surface, the heat conductive plate 51 can be easily fixed in close contact, and cooling can be made more efficient at low cost.

Further, the cooling unit 5 is not necessarily configured to include the heat conductive plate 51 and the cooling pipe 52. FIG. 6 is an external perspective view showing another configuration example of the cooling unit 5, and FIG. 7 is an exploded perspective view of the chamber 2. The cooling unit 5 includes a recess 55 formed in a heat conductive plate 58 made of a material having excellent thermal conductivity, which is closely fixed along the L-shaped surface of the divided bodies 20a and 20b, and a lid plate covering the recess 55. Includes 56 and. The recess 55 may be formed directly on the outer surface of the split pieces 20a and 20b. As shown in FIG. 7, the outer wall of each of the recesses 55 of the heat conductive plate 58 is provided with holes 57 at two locations on the outer side and the inner side, and the inner holes 57 are connected to each other by the connectors 53 and 53 and the connecting pipe 54. ing. Further, the outer holes 57 are each connected to a cooling medium supply device (not shown) via a connector 53. Further, the recess 55 is provided with an inner wall 59 so as to separate the portions where the holes 57 are provided, and a flow that generates a constant flow in a cooling medium such as cooling water supplied from one of the holes 57. Forming a road. In the examples shown in FIGS. 6 and 7, it is expected that the range in which the cooling medium flows is expanded, the chances of heat exchange with the split bodies 20a and 20b are further increased, and the cooling effect is improved.

The chamber 2 further includes a conductive portion 6. The conductive portion 6 is made of a metal having excellent conductivity such as copper, and includes connected split bodies 20a and 20b, that is, a thin plate-shaped conductor 60 that circulates along the chamber 2. One end of the conductor 60 is fixed to a connecting body 64 fixed on the flange 28 of the split body 20b. The connecting body 64 is made of a conductive material and has a thickness substantially equal to the thickness of the flange 28. Then, the conductor 60 is provided along the chamber 2 and at a predetermined distance from the heat conductive plate 51 of the cooling unit 5 on the cooling unit 5 side of the divided bodies 20a and 20b so as not to come out from the outer periphery of the main body portion 20. It is provided at a distance. Specifically, the other end of the conductor 60 is supported by a support 62 fixed at a position closer to the lid plate 25 on the heat conductive plate 51 on the split body 20b side, and the intermediate portion is on the split body 20a side. It is supported by a support 63 fixed at a position closer to the lid plate 25 on the heat conductive plate 51. The supports 62 and 63 are both formed of an insulating material, and have a function of forming a predetermined distance between the conductor 60 and the heat conductive plate 51 and avoiding electrical contact with the cooling unit 5. It exerts its effect and is fixed at a position avoiding the cooling pipe 52. The conductor 60 fixed by the connecting body 64 and the supports 62 and 63 has a shape in which the silhouette fits within the divided bodies 20a and 20b when viewed from the central axis direction of the ring shape of the connected bodies 20a and 20b. It is done like this. That is, the conductor 60 in the first embodiment has a shape that fits in the surface (square annular surface) excluding the outer surface and the inner surface of the main body portion 20 composed of the connected split bodies 20a and 20b. That is, the outer circumference of the conductor 60 when viewed from the central axis direction of the ring shape is smaller than the outer circumference of the main body portion 20, and in addition, the inner circumference is larger than the inner circumference of the main body portion 20. The size of the conductor 60 can be suppressed from increasing in size by at least having a size within a range that does not protrude outward from the outer shape of the main body portion 20 when viewed from the central axis direction. Further, the other end of the conductor 60 supported by the support 62 is bent inward and extends inward of the chamber 2, and the connecting rod 61 is provided so as to stand up at the tip of the extension end. The conductor 60 extends from the connecting rod 61 located above the center of the chamber 2 to the split body 20a side along the shape of the split body 20b, and further returns to the split body 20b side along the shape of the split body 20a to form the portion. It is connected to the flange 28 of the body 20b.

In the plasma generator 1 using the chamber 2 configured as described above, the high frequency power supply 4 is connected to the connecting rod 61 of the conductive portion 6, and the flat plate portion of the outlet port 22 is connected to the ground potential. When a voltage from the high-frequency power source 4 is applied, a current is transmitted from the connecting rod 61 through the conductor 60 counterclockwise in FIG. 2, and is transmitted from the flange 28 of the metal body 20b via the connecting body 64 to the flange 28. Flows to the side opposite to the insulator 23 in contact with the body, and is transmitted from the other end side of the body 20b to the body 20a via the spacer 24. The current transmitted to the split body 20a flows to the ground potential via the outlet port 22. That is, the current in the conductor 60 and the current flowing on the split body 20a and the split body 20b have the same direction, and flow spirally from the connecting rod 61 to the ground potential. At this time, the conductive portion 60 exerts a function as an additional inductance component with respect to the inductance component formed by the main body portion 20 (parts 20a, 20b and the spacer 24) of the chamber 2.

The conductive portion 6 is not an indispensable constituent requirement. The cooling unit 5 of the present disclosure can also be applied to a chamber having a configuration that does not include the conductive unit 6.

(Embodiment 2)
FIG. 8 is a perspective view showing the appearance of the chamber 2 according to the second embodiment, and FIG. 9 is an exploded perspective view of the chamber 2. Since the plasma generator 1 of the second embodiment is the same as that of the first embodiment except for the configuration of the cooling unit 5 and the arrangement of the magnetic core 3, the common constituent members will be described with the same reference numerals. Is omitted.

The cooling unit 5 in the second embodiment includes a heat conductive plate 51 and a cooling pipe 52 fixed on the heat conductive plate 51. Both the heat conductive plate 51 and the cooling pipe 52 are made of a material having excellent heat conductivity such as copper. As shown in FIGS. 8 and 9, the heat conductive plate 51 according to the second embodiment is formed in a substantially C shape over both the split bodies 20a and 20b so as to be along the outer surface thereof, and the split body 20a is formed. , 20b is closely fixed to the outer surface. The cooling pipe 52 is composed of a single bent pipe along the center line of the heat conductive plate 51. Both ends of the cooling pipe 52 are bent outward and extended to the outside of the divided bodies 20a and 20b, respectively, and the extended ends are connected to a cooling medium supply device (not shown) via a connector 53. .. As a result, the cooling medium such as cooling water supplied from the supply device flows from the outer extension end of the cooling pipe 52 on the split body 20a side through the inside of the cooling pipe 52 to the split body 20b side as it is, and flows to the split body 20b side as it is. Return to the feeder or drain from the outer extension of the. As a result, the heat conductive plate 51 in contact with the cooling pipe 52 is cooled, and the heat conductive plate 51 suppresses the temperature rise of the split bodies 20a and 20b.

In the second embodiment, the support 63 on the side of the split body 20a of the conductive portion 6 is fixed on the heat conductive plate 51, but is shown in FIG. 9 in order to avoid the cooling pipe 52 which is a single bent pipe. As described above, a semicircular notch is formed on the surface in contact with the heat conductive plate 51 so that the cooling pipe 52 can pass through the notch.

Since the heat conductive plate 51 in the second embodiment has a larger area than the heat conductive plate 51 in the first embodiment, the cooling area is further increased and the cooling effect is improved. Further, in the second embodiment, since the connecting pipe 54 is not required and the cooling water is not passed inside the inner circumference of the main body portion 20, the space through which the connecting pipe 54 passes is not required, and the diameter of the main body portion 20 is increased. It is also possible to make the entire plasma generator 1 even smaller.

Further, in the second embodiment, the arrangement mode of the magnetic core 3 is shown. The magnetic core 3 is an annular body formed by joining two ferrite magnetic materials bent and molded in a U shape by itself. The magnetic core 3 is provided at a portion corresponding to each of the insulator 23 and the spacer 24 of the chamber 2 and a middle portion of each of the divided bodies 20a and 20b. The magnetic core 3 is provided so as to surround the outside of both the insulator 23 and the conductor 60 in a cross-sectional view so as to follow a direction (poloidal direction) that orbits the cross section of the main body portion 20 of the chamber 2. .. At the corresponding portion of the spacer 24, the magnetic core 3 is provided so as to surround the outside of the conductor 60 of the spacer 24, the cooling portion 5, and the conductive portion 6. The magnetic cores 3 provided in the middle of the split bodies 20a and 20b are also provided so as to surround the outside of the split bodies 20a and 20b, the cooling section 5 and the conductor 60, respectively. The number of magnetic cores 3 is not limited to four as shown in FIGS. 8 and 9, but may be three or less, for example, only one. When the number of magnetic cores 3 is one, it may be provided at a location corresponding to the spacer 24.

In this way, in the second embodiment, the conductive heat conductive plate 51 and the cooling pipe 52 extending over both the split body 20a and the split body 20b are used for the cooling unit 5. When the high-frequency power supply 4 is connected to the connecting rod 61 of the conductive portion 6 of the chamber 2 and the flat plate portion of the outlet port 22 is connected to the ground potential, the cooling portion 5 also serves as a current path. Since the heat conductive plate 51 and the cooling tube 52 pass through the inside of the magnetic core 3, the amount of current passing through the inside of the magnetic core 3 can be increased, and the inductance of the chamber 2 as a whole can be increased.

(Embodiment 3)
10 and 11 are perspective views showing the appearance of the chamber 2 in the third embodiment, and FIG. 12 is an exploded perspective view of the chamber 2. The outline of the plasma generator 1 according to the third embodiment is the same as that of the first and second embodiments except for the specific shape of the chamber 2. The magnetic core 3 of the plasma generator 1 of the third embodiment will be described later. The chamber 2 of the third embodiment is not provided with the conductive portion 6, but includes the same constituent members as the chambers 2 of the first and second embodiments. The same reference numerals are given to these common constituent members, and some detailed description thereof will be omitted.

Also in the third embodiment, the chamber 2 is configured so that the divided bodies 20a and 20b having the same shape are connected via the insulator 23 and the spacer 24 to form a square ring as a whole. In the split bodies 20a and 20b in the third embodiment, one of the corners of the U-shape is cut diagonally at a depth at which the through hole is exposed, and the other corner is diagonally cut so that the through hole is not exposed. It has been excised. Flange 28s for connection are integrally formed at both ends of the split bodies 20a and 20b. The flange 28 in the third embodiment is formed so that the end face expands in the central axis direction of the square ring, that is, its size is expanded in the central axis direction with respect to the vertical cross section of the split bodies 20a and 20b. ing. Further, as shown in FIGS. 10 to 12, the flange 28 near the corner, which is cut shallowly, is provided with a rectangular notch in the center, and the inner side surface of the notch is divided into 20a and 20b. It is designed to be continuous with the outer surface of the character.

The insulator 23 and the spacer 24 are rectangular equal-thick plates larger than the cross-sectional outer shape of the split bodies 20a and 20b and the flange 28, and have the same diameter as the holes of the split bodies 20a and 20b at the center of each. A hole (not shown) is formed. The insulator 23 is made of an insulating material having appropriate strength, such as ceramics. The spacer 24 is made of a metal material having the same or different conductivity as the split bodies 20a and 20b and having excellent conductivity, and has a rectangular notch corresponding to the notch of the flange 28 at the center of both short sides.

In the chamber 2, the flanges 28 in which the notches of the divided bodies 20a and 20b are formed face each other and a spacer 24 is interposed between the end faces thereof, and the other flanges 28 face each other and the insulator 23 is between the end faces. , And are integrally connected by a plurality of fixing bolts 27 passed through each of the flanges 28. An outlet port 22 is provided in the deeply cut portion of the split body 20a, and a lid plate 25 is provided in the deep cut portion of the split body 20b so as to cover the cut portion. A gas pipe 210 corresponding to the inlet port is formed in the shallow cut portion of the split body 20b so as to be conductive with the internal through hole. As a result, the chamber 2 is configured by providing a gas flow path 29 that is continuous in a tubular shape by the central hole of the split bodies 20a and 20b and the central hole of the insulator 23 and the spacer 24.

The chamber 2 further includes two cooling portions 5c that are closely fixed to both of the square annular surfaces of the main body portion 20. The cooling portion 5c includes a recess 55 formed in a horseshoe-shaped (U-shaped) heat conductive plate 58 that is closely fixed along the outer surfaces of the divided bodies 20a and 20b, and a lid plate 56 that covers the recess 55. .. The central portion of the heat conductive plate 58 is adapted to fit into the notched portion of the flange 28. Both ends of the heat conductive plate 58 are obliquely cut so as to be along the boundary surface of the split body 20b with the lid plate 25 and the boundary surface of the split body 20a with the outlet port 22. The lid plate 56 has a wall (not shown) projecting from the surface facing the recess 55 and has a T-shaped cross section, and this wall serves as an inner wall to form a fine circulation flow path in the recess 55. I am trying to do it. As shown in the exploded view of FIG. 12, the outer wall of each of the recesses 55 of the heat conductive plate 58 has holes 57 in two places corresponding to the horseshoe-shaped heel portion (the portion corresponding to the U-shaped corner portion). Is provided and is connected to a cooling medium supply device (not shown) via a connecting pipe 59. As shown in FIG. 11, the connecting pipe 59 on the split body 20a side is bent toward the split body 20a side. By connecting the bent connection pipes 59 of the cooling unit 5c fixed to the opposite side of the main body portion 20, the circulation flow path of the cooling medium is continuous between the cooling units 5c and 5c fixed on both sides. Will be. In this way, in the heat conductive plate 58 in which the flow path is formed inside without using the cooling pipe 52, the range in which the cooling medium flows is expanded, the chances of heat exchange with the split bodies 20a and 20b are further increased, and cooling is performed. It is expected that the effect will be improved.

In the plasma generator 1 using the chamber 2 in the third embodiment, the high frequency power supply 4 is connected to the flange 28 in contact with the insulator 23 of the split body 20b, and the flat plate portion of the outlet port 22 on the split body 20a side is connected to the ground potential. To do. When a voltage from the high-frequency power supply 4 is applied, a current flows from the flange 28 of the split body 20b to the side opposite to the insulator 23 in contact with the flange 28, and a spacer is applied from the other end side of the split body 20b. It is transmitted to the split body 20a via 24. The current transmitted to the split body 20a flows to the ground potential via the outlet port 22. Further, when the current flows from the flange 28 of the split body 20b to the split body 20b, it flows to the heat conductive plate 58 of the cooling unit 5c in contact with the outer surface thereof, and further grounds from the outlet port 22 via the other end on the outlet port 22 side. It flows to the electric potential. In this way, the high-frequency current supplied from the high-frequency power supply 4 flows through the main body portion 20 (divisions 20a, 20b and spacer 24) and the cooling portion 5c of the chamber 2 in the circumferential direction (toroidal direction), and the ring of the main body portion 20. A high-frequency magnetic field can be generated along the direction (poloidal direction) that orbits the cross section of. Since the current path of the cooling unit 5c is along the main body portion 20, the effect of increasing the inductance component can be exerted. Further, in the third embodiment, since the connecting pipe 54 inside the inner circumference of the square ring is not required, the diameter of the main body portion 20 can be further reduced to make the plasma generator 1 compact.

Next, a specific example of the case where the magnetic core 3 is provided in the chamber 2 will be described with reference to the drawings. FIG. 13 is a perspective view showing an example of the arrangement mode of the magnetic core 3 of the chamber 2 in the third embodiment. The magnetic core 3 alone is the same as that described in the second embodiment. Also in the third embodiment, the magnetic core 3 is provided at a portion corresponding to each of the insulator 23 and the spacer 24 of the chamber 2 and a middle portion of each of the divided bodies 20a and 20b. The magnetic core 3 is provided so as to surround the outside of both the insulator 23 and the cooling portion 5c in a cross-sectional view so as to follow a direction (poloidal direction) that orbits the cross section of the main body portion 20 of the chamber 2. At the corresponding portion of the spacer 24, the magnetic core 3 is provided so as to surround the outside of the spacer 24 and the cooling portion 5c. The magnetic cores 3 provided in the middle of the divided bodies 20a and 20b are also provided so as to surround the outside of the divided bodies 20a and 20b and the cooling portion 5c, respectively. As shown in FIG. 13, the magnetic core 3 may be not only four examples but also three or less, for example, only one. When the number of magnetic cores 3 is one, it may be provided at a location corresponding to the spacer 24. Further, as shown in FIGS. 10 to 13, the cooling effect is further improved by providing the cooling portions 5c on both sides of the main body portion 20.

In this way, in the third embodiment, the cooling unit 5c uses the conductive heat conductive plate 58 and the lid plate 56 that span both the body 20a and the body 20b, and the cooling unit 5c is also used as a current path. It is configured to pass through the inside of the magnetic core 3. As a result, not only the cooling effect can be improved, but also the amount of current passing through the inside of the magnetic core 3 can be increased, and the inductance of the chamber 2 as a whole can be increased.

It should be noted that the present embodiment disclosed as described above is an example in all respects and should be considered not to be restrictive. The scope of the present invention is indicated by the scope of claims, not the above-mentioned meaning, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Plasma generator 2 Chamber 20 Main body 20a, 20b Divided 23 Insulator 29 Gas flow path 3 Magnetic core 4 High frequency power supply 5, 5c Cooling part 51, 58 Heat conduction plate 52 Cooling pipe 55 Recess 56 Lid plate

Claims (4)

A plasma generator including a chamber formed of a conductive material in an annular shape and having a gas flow path for a material gas formed inside along the shape, and a high-frequency power source for supplying a high-frequency current to the chamber.
The chamber
The main body part with a part of the ring shape missing,
Wherein being in close contact with the outer surface of the body portion, viewed contains a cooling unit to transfer heat from the cooling medium supplied from the outside to the body portion,
The main body of the chamber
Two separate bodies formed of a conductive material having a rectangular vertical cross section and bent into the same shape with through holes passing through the centers of each side.
With an insulator having a cross-sectional shape corresponding to the cross-sectional shape of the split body
Including
The end faces of the two split bodies are opposed to each other, and the insulator is interposed between one end face and a conductor spacer is interposed between the other end faces so as to form a square ring.
The cooling unit
A heat conductive plate tightly fixed along the outer surface of the main body,
With a cooling tube made of a heat conductor that is fixed to the heat conductive plate and the cooling medium flows inside.
Including
The plasma generator is characterized in that the heat conductive plate of the cooling unit includes one heat conductive plate that is closely fixed along the outer surface over the two divided bodies. The outer surface of the main body portion has a flat surface and
The plasma generator according to claim 1 , wherein the heat conductive plate is closely fixed to a part or all of the flat surface. The cooling unit
A recess provided on the outer surface of the main body portion through which the cooling medium flows,
The plasma generator according to claim 1, further comprising a lid covering the recess. The cooling unit includes a member of a conductive material and contains a member.
An annular magnetic core provided at one or more locations in the chamber is further provided.
The plasma generator according to any one of claims 1 to 3 , wherein the magnetic core is provided so as to surround at least a part of the outside of the chamber and the cooling unit in a cross-sectional view.

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