JP2010086685A - Plasma treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment device maintaining an aligned state before and after plasma generation. <P>SOLUTION: The plasma treatment device 1 includes: a ground potential-applied cylindrical case 11 whose one end is closed with a closing plate 11b and other end is formed to be open-ended; and a rod-shaped radiator 14 disposed upright in the plate 11b so as to extend in a cylinder length direction of the case 11. With discharge gas W supplied to the vicinity of an open end-side leading end of the radiator 14, the radiator 14 radiates a supplied high-frequency signal S1 to generate a plasma P in the vicinity of the leading end. The device also includes a power supply conductor 13 connected to a power supply position A apart from a base end of the radiator 14 fixed to the closing plate 11b by a predetermined distance L2 to supply the high-frequency signal S1 to the radiator 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes a cylindrical casing whose one end is closed by a closing plate, and a radiation conductor erected on the inner surface of the closing plate so as to extend along the cylinder length direction of the casing. The present invention relates to a plasma processing apparatus for generating plasma near the tip of a radiation conductor.

As this type of plasma processing apparatus, a plasma processing apparatus (microwave plasma generator) disclosed in Patent Document 1 below is known. This plasma processing apparatus includes a resonator configured by fixing a lid to the upper end of a cylindrical outer tube, a coaxial line disposed near the upper end of the outer tube, and an inner portion fixed to the center of the lid. And a conductor. Further, the conductor (center conductor) of the coaxial line is refracted in the direction of the lid in the outer tube, and the tip is connected to the lid. The length of the inner conductor is set to (λ / 2) × n + (λ / 4). A gas introduction port is formed in the outer tube. In this plasma processing apparatus, a microwave is generated in the resonator by transmitting the microwave converted into the coaxial mode to the inner conductor via the coaxial line and generating a high electric field at the tip of the inner conductor. For this reason, this plasma processing apparatus eliminates the need for an impedance matching device, and also eliminates the need for a reflecting plate and the like, thereby enabling downsizing of the entire apparatus.
JP-A-6-1888094 (page 2-3, FIG. 2)

  However, as a result of intensive studies on the above-described conventional plasma processing apparatus by the present inventors, it has been found that the following problems exist in this plasma processing apparatus. That is, in this plasma processing apparatus, the generated plasma itself has conductivity, so that the apparent length (electrical length) of the inner conductor changes before and after the generation of the plasma. The resonance frequency of the inner conductor changes at. Therefore, in this plasma processing apparatus, when the length of the internal conductor is defined with reference to the resonance frequency before plasma generation, the plasma processing apparatus becomes inconsistent after plasma generation. Therefore, this plasma processing apparatus needs to be supplied with a high-frequency signal having a large power in order to maintain the generation of plasma due to an increase in reflection of the high-frequency signal, resulting in a decrease in power efficiency. There is a problem.

  The present invention has been made to solve such a problem, and a main object of the present invention is to provide a plasma processing apparatus capable of maintaining an alignment state before and after plasma generation.

  In order to achieve the above object, a plasma processing apparatus according to claim 1, wherein a ground potential is applied, one end is closed by a closing plate, and the other end is formed at an open end. And a rod-shaped radiation conductor erected so as to extend along the cylinder length direction of the casing on the inner surface of the closing plate, and plasma discharge near the open end side of the radiation conductor A plasma processing apparatus for generating plasma in the vicinity of the tip by radiating a high-frequency signal supplied by the radiation conductor in a state where a working gas is supplied, the substrate being fixed to the closing plate in the radiation conductor A power supply conductor is provided that is connected to a power supply position that is separated from the end by a predetermined distance and supplies the high-frequency signal to the radiation conductor.

  The plasma processing apparatus according to claim 2 is the plasma processing apparatus according to claim 1, wherein the radiation conductor is formed in a cylindrical shape and is disposed in the radiation conductor so as to protrude from the tip of the radiation conductor. The plasma discharge gas is supplied to the vicinity of the tip of the radiation conductor by the insulation tube, and the plasma is generated in the vicinity of the tip in the insulation tube.

  According to a third aspect of the present invention, there is provided the plasma processing apparatus according to the first aspect, wherein the radiation conductor is formed in a cylindrical shape, and the through-hole communicating with the inside of the radiation conductor is formed in the blocking plate. The plasma discharge gas is supplied to the vicinity of the tip of the radiation conductor by the processing target tube inserted into the through hole and the radiation conductor, and the plasma is generated near the tip of the processing target tube. Be made.

  According to the plasma processing apparatus of claim 1, the plasma processing apparatus is configured to supply a high-frequency signal via a power supply conductor to a power supply position that is spaced a predetermined distance from a base end portion fixed to the closing plate in the radiator. Before and after the occurrence, the alignment state (good and substantially constant VSWR state) can be maintained. Therefore, both the power efficiency at the time of plasma generation and the power efficiency after plasma generation (when the plasma generation state is maintained) can be made good, so that the power efficiency of the plasma processing can be sufficiently improved.

  According to the plasma processing apparatus of claim 2, the radiation conductor is formed in a cylindrical shape, an insulating tube is disposed in the radiation conductor so as to protrude from the tip of the radiation conductor, and the plasma discharge gas is insulated. By supplying the plasma near the tip of the radiating conductor through a tube and generating plasma near the tip of the radiating conductor in the insulating tube, the plasma processing efficiency is sufficiently improved, and the plasma diameter is defined by the inner diameter of the insulating tube. can do. For this reason, for example, by reducing the inner diameter of the insulating tube, it is possible to surface-treat only a narrow range on the surface of the object to be processed.

  According to the plasma processing apparatus of claim 3, the radiation conductor is formed in a cylindrical shape, the through-hole communicating with the inside of the radiation conductor is formed in the closing plate, and the plasma discharge gas is placed in the through-hole and in the radiation conductor. Is supplied to the vicinity of the tip of the radiation conductor by the processing target tube inserted into the processing target tube, and plasma is generated in the vicinity of the leading end in the processing target tube, thereby sufficiently improving the power efficiency of the plasma processing and the processing target tube. The inner surface of can be surface-treated.

  Hereinafter, the best mode of a plasma processing apparatus according to the present invention will be described with reference to the accompanying drawings.

  A plasma processing apparatus 1 shown in FIG. 1 includes a high-frequency power source 2, a plasma generator 3, and a table 4. In addition, the plasma processing apparatus 1 generates and generates plasma in the plasma generating unit 3 by supplying the high frequency signal S1 generated in the high frequency power source 2 to the plasma generating unit 3 through the coaxial cable 5. Plasma is radiated to the processing object 6 placed on the table 4 so that the surface thereof can be subjected to plasma processing. As an example, the plasma processing apparatus 1 uses a member (for example, a sheet-like or plate-like member) formed of an organic material such as a resin as a processing object 6, sterilization treatment, cleaning treatment, and hydrophilicity of the surface thereof. Execute improvement processing.

  The high frequency power supply 2 generates a high frequency signal (for example, a quasi microwave of about 2.45 GHz) S1 in a quasi-microwave band (1 GHz to 3 GHz) or a microwave band (3 GHz to 30 GHz) with a predetermined power, and plasma It functions as a high-frequency signal generation unit that outputs to the generation unit 3. In this example, the high-frequency power supply 2 employs a configuration that outputs the quasi-microwave as the high-frequency signal S1, but a configuration that outputs the microwave as the high-frequency signal S1 can also be employed. Further, a matching unit may be provided between the high frequency power source 2 and the plasma generating unit 3 in order to increase the supply efficiency of the high frequency signal S1 from the high frequency power source 2 to the plasma generating unit 3.

  As shown in FIG. 1 as an example, the plasma generating unit 3 includes a housing 11, a coaxial connector 12, a feeding conductor 13, and a radiator (antenna) 14 as a radiation conductor in the present invention. As an example, the housing 11 includes a conductive cylinder 11a that is open at both ends, a conductive blocking plate 11b, and an insulating tube 11c. One end (upper end in FIG. 1) is closed, and the other The end portion (the lower end portion in FIG. 1) is formed at an open end to constitute a torch type housing, and a ground potential is applied.

  Specifically, as shown in FIG. 1, the casing 11 is a closed body in which one end portion (upper end portion in FIG. 1) of the cylindrical body 11a is disposed in close contact with the one end portion. It is configured as a torch-type housing that is closed by the plate 11b and whose other end becomes an open end. Further, as shown in FIG. 2, the cylindrical body 11a has a quadrangular cross section on the outer peripheral surface along a plane orthogonal to the central axis X (that is, the outer shape is a rectangular cylindrical body). Since the cross-sectional shape of the peripheral surface is circular, it substantially functions as a cylindrical body. Further, as shown in FIG. 1, the cylinder 11a is defined to have a length (cylinder length) longer than the length L1 of the radiator 14, and the tip of the radiator 14 protrudes from the open end of the cylinder 11a. It has a configuration that does not. As shown in FIG. 1, the insulating tube 11c is disposed on the inner peripheral surface of the cylindrical body 11a, and when the output power of the high frequency signal S1 is increased, unnecessary discharge from the radiator 14 to the housing 11 is performed. It functions so as not to generate.

  In this example, as shown in FIG. 1, a through hole 21 for introducing a high-frequency signal S <b> 1 into the housing 11 is formed in the cylindrical body 11 a. Further, as an example, the closing plate 11b is formed with a through hole 22 for connecting a supply pipe 7 for supplying a plasma discharge gas G (hereinafter also referred to as “discharge gas G”) into the cylindrical body 11a. ing. In this case, as shown in FIGS. 1 and 2, the position of the through hole 22 is a position deviated from the central axis X of the cylinder 11a (specifically, a radiator disposed on the central axis X as described later). 14 is a position that does not interfere with 14). The through hole 22 for connecting the supply pipe 7 can be formed in the cylindrical body 11a instead of the blocking plate 11b. In this example, as an example, a gas (eg, argon gas or helium gas) that has a low ionization voltage and easily generates plasma is used as the discharge gas G.

  As shown in FIG. 1, the coaxial connector 12 is attached to the outer peripheral surface of the cylindrical body 11 a so as to close the through-hole 21 while being attached to the tip of the coaxial cable 5 connected to the high-frequency power source 2. ing. For example, as shown in FIGS. 1 and 2, the power supply conductor 13 is formed in a rod shape (substantially straight rod shape) using a highly conductive wire, and one end side is connected to the core wire 12 a of the coaxial connector 12. At the same time, the other end is connected to the feeding position A of the radiator 14. In this case, the power feeding position A is defined as a position separated from the base end portion fixed to the closing plate 11b in the radiator 14 by a predetermined distance L2. Here, the predetermined distance L2 is preferably defined in a range of λ / 10 ≧ L2> 0, where λ is the wavelength of the high-frequency signal S1. As a result, the radiator 14, the closing plate 11b connected to the radiator 14 and the feed conductor 13 constitute an inverted F-shaped antenna, which reduces the change in VSWR before and after plasma generation (ignition), as will be described later. This is a possible configuration. Note that, in the configuration in which the predetermined distance L2 exceeds λ / 10, the VSWR before plasma generation begins to deteriorate as described later (that is, the ignitability of plasma starts to decrease). For this reason, L2 is preferably λ / 10 or less.

  The radiator 14 is formed in a single bar shape using a conductive material. Specifically, the radiator 14 is composed of one conductive columnar body (in this example, a cylindrical body) whose length L1 is defined as ((1/4 + n / 2) × λ). Here, n is an integer greater than or equal to 0. In this example, n = 0 is set as an example, and the length L1 of the radiator 14 is (λ / 4. The frequency of the high-frequency signal S1 is 2.45 GHz as an example. Therefore, it is defined as 122.45 mm / 4 = 30.6 mm). In addition, the radiator 14 is not limited to a columnar body, and can be configured by a plate-shaped body such as a rectangular parallelepiped or a bowl-shaped body (half-pipe-shaped body). Further, as shown in FIG. 1, the radiator 14 is disposed inside the casing 11 along the cylinder length (longitudinal) direction of the casing 11. In this example, as an example, the radiator 14 is closed in a state of being located on the central axis X of the cylindrical body 11a (in a state of extending along the cylindrical length direction of the casing 11) inside the cylindrical body 11a. Standing on the inner surface of the plate 11b (standing in an electrically connected state).

  As shown in FIG. 1, the table 4 is disposed to face the other end (opening end) of the housing 11, and the processing object 6 is placed on the surface (mounting surface) on the housing 11 side. It is configured so that it can be placed. In this example, as an example, the mounting surface of the table 4 is formed on a plane orthogonal to the central axis X of the cylindrical body 11a.

  Next, the operation of the plasma processing apparatus 1 will be described. It is assumed that the processing object 6 is placed on the table 4.

  In the plasma processing apparatus 1, when performing the plasma processing on the processing object 6, first, the discharge gas G is supplied into the housing 11 from the gas supply unit (not shown) via the supply pipe 7. Next, in the supply state of the discharge gas G, the high-frequency power source 2 starts outputting the high-frequency signal S1 to the plasma generator 3. The high-frequency signal S1 output from the high-frequency power source 2 is supplied from the power supply position A to the radiator 14 via the coaxial cable 5, the coaxial connector 12, and the power supply conductor 13. Thereby, the radiator 14 prescribed | regulated to the length L1 of (lambda) / 4 resonates with the high frequency signal S1. The resonator 14 in the resonance state operates as a resonance monopole, and the voltage is maximized on the front end side (the lower end in FIG. 1 and the front end in the present invention) located on the opening end side of the housing 11. For this reason, the electric field intensity is maximized near the tip of the radiator 14 in the plasma generating unit 3 (near the tip), and the inside of the plasma generating unit 3 in which the discharge gas G that easily generates plasma exists (that is, in the casing 11). Then, plasma P is generated near the tip. In this case, since the high frequency power supply 2 supplies a quasi-microwave or a microwave to the plasma generator 3 as the high frequency signal S1, the plasma P is generated in a high density state. Further, since the discharge gas G supplied from the supply tube 7 flows in the cylinder 11a along the cylinder length direction and flows out from the opening end of the housing 11, the generated plasma P is shown in FIG. Thus, it extends along the cylinder length direction (along the central axis X of the cylinder 11a) from the tip of the radiator 14, and is radiated from the open end of the cylinder 11a to the processing object 6. Thereby, the processing object 6 is surface-treated by the plasma P emitted from the housing 11.

  At this time, due to the fact that the plasma P itself has conductivity, the apparent length (electrical length) of the radiator 14 is before the plasma generation (the length of the radiator 14 only) and after the plasma generation ( It varies depending on the length of the radiator 14 and the total length of the plasma P). Therefore, in the conventional plasma processing apparatus, the resonance frequency of the plasma generation unit 3 before and after the generation of the plasma P changes greatly. Therefore, according to an experiment by the inventors (an experiment in which the frequency of the high-frequency signal S1 is 2.45 GHz and the length L1 of the radiator 14 is λ / 4 (= 30.6 mm)), as shown in FIG. In addition, when the length L1 of the radiator 14 is defined with reference to the resonance frequency before plasma generation (before ignition), a mismatched state occurs after plasma generation (after ignition), and VSWR before plasma generation (same figure). It was confirmed that VSWR after plasma generation (value marked with ◯ in the figure: 61.5) greatly deteriorated compared with the value marked with □ in the middle: 12.4).

  On the other hand, in the plasma processing apparatus 1 according to the present invention, the feeding position A of the high-frequency signal S1 is defined at a position separated from the closing plate 11b in the radiator 14 by a predetermined distance L2, as described above. Therefore, as shown in FIG. 7, for example, the predetermined distance L2 is changed to 2 mm (= λ / 61.2), 3 mm (= λ / 40.8), and 4 mm (= λ / 30.6) to generate plasma. When the change in VSWR before and after is measured, the measured VSWR before and after plasma generation at each predetermined distance L2 is (11.1, 18.6), (13.1, 17), respectively. 4) and (18.5, 17), and at least in the range of λ / 30.6 ≧ L2 ≧ λ / 61.2, the VSWR in the alignment state in the conventional plasma processing apparatus (VSWR before plasma generation) And almost the same value (all VSWRs are less than 20). As a result, it was confirmed that the change in VSWR before and after plasma generation was significantly reduced to a level where it could be said that the change in VSWR before and after plasma generation did not change substantially compared to the conventional plasma processing apparatus. That is, in the plasma processing apparatus 1, it was confirmed that a good alignment state was maintained before and after plasma generation. The reason for this is that the high-frequency signal S1 fed from the feeding position A causes the path from the proximal end of the radiator 14 to the distal end of the radiator 14 and the path transmitted from the feeding position A to the distal end of the radiator 14. Since resonance occurs in two paths, it is considered that one of the causes is that the Q of the radiator 14 becomes broad (broadband).

  From the results of the experiment shown in FIG. 7, as the predetermined distance L2 is increased to 2 mm, 3 mm, and 4 mm, the VSWR after plasma generation is maintained substantially constant from 18.6 to 17.4, 17 (slightly However, the VSWR before the plasma generation tends to gradually increase from 11.1 to 13.1, 18.5 (decrease in plasma ignitability). For this reason, it is considered that if the predetermined distance L2 to the power feeding position A is too long, the VSWR before the plasma generation is further increased and the ignitability of the plasma is lowered. For this reason, it is considered that the predetermined distance L2 is preferably λ / 10 or less at the longest.

  As described above, according to the plasma processing apparatus 1, the high-frequency signal S <b> 1 is supplied via the power supply conductor 13 to the power supply position A that is separated by the predetermined distance L <b> 2 from the base end portion fixed to the closing plate 11 b in the radiator 14. By adopting the configuration, the plasma generating unit 3 can be maintained in an aligned state (good and substantially constant VSWR state) before and after plasma generation. Therefore, both the power efficiency at the time of plasma generation and the power efficiency after plasma generation (when the plasma generation state is maintained) can be improved, and as a result, the power efficiency of the plasma processing in the plasma processing apparatus 1 can be sufficiently improved. Can be made.

  The present invention is not limited to the configuration shown in the above embodiment. For example, in the above-described embodiment, the insulating tube 11c is disposed on the inner peripheral surface of the cylinder 11a, and the discharge gas G is supplied from the supply tube 7 to the entire inside of the cylinder 11a to generate the plasma P from the cylinder 11a. However, as in the plasma processing apparatus 1A shown in FIGS. 3 and 4, the radiator 14 is formed in a cylindrical shape and an insulating tube 11c is disposed inside the radiator 14, It is also possible to supply the discharge gas G through the insulating tube 11c and generate the plasma P in the insulating tube 11c so that the plasma P is emitted from the insulating tube 11c to the object 6 to be processed. Hereinafter, the plasma processing apparatus 1A will be described.

  First, the configuration of the plasma processing apparatus 1A will be described. In addition, about the same structure as the plasma processing apparatus 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted and only a different structure is demonstrated.

  A plasma processing apparatus 1 </ b> A shown in FIG. 3 includes a high-frequency power source 2, a plasma generator 3 </ b> A, and a table 4, and the plasma generator 3 </ b> A is different from the plasma generator 3 of the plasma processing apparatus 1. Further, in this example, the insulating tube 11c having the same function as the insulating tube 11c in the plasma processing apparatus 1 is also made to function as a supply pipe for the discharge gas G, so that it is different from the plasma processing apparatus 1 in that there is no supply pipe 7. is doing.

  As shown in FIGS. 3 and 4, the plasma generator 3 </ b> A includes a housing 11, a coaxial connector 12, a power supply conductor 13, and a radiator (antenna) 14. The housing 11 includes a cylindrical body 11a, a closing plate 11b, and an insulating tube 11c, one end (upper end in FIG. 3) is closed, and the other end (lower end in FIG. 3) is open. It is formed at the end to constitute a torch-type housing, and a ground potential is applied. Specifically, as shown in FIG. 3, the casing 11 is a closed body in which one end portion (upper end portion in FIG. 1) of the cylindrical body 11 a is disposed in close contact with the one end portion. It is configured as a torch-type housing that is closed by the plate 11b and whose other end becomes an open end. In addition, in this example, the through hole 22 formed in the closing plate 11b for supplying the discharge gas G has a central axis that is coaxial with the central axis X of the cylindrical body 11a (that is, the closing plate 11b has a central axis). Formed in the center). The radiator 14 is formed in a cylindrical shape whose inner diameter is defined to be equal to or larger than the inner diameter of the through hole 22, and is erected on the inner surface of the closing plate 11 b so that the central axis thereof is coaxial with the central axis X of the cylindrical body 11 a. Has been. As a result, the inside of the radiator 14 is in communication with the through hole 22. The outer diameter of the insulating tube 11c is smaller than the inner diameter of the through hole 22, and is inserted into the through hole 22 and the radiator 14 as shown in FIGS. 3 and 4, and from the inner surface of the blocking plate 11b. The protruding length is defined to be substantially the same as the entire length of the cylinder 11a. Thereby, the edge part (end part by the side of the opening end of the cylinder 11a) which protruded from the radiator 14 in the insulating tube 11c is in the same state as this opening end.

  Next, the operation of the plasma processing apparatus 1A will be described.

  In the plasma processing apparatus 1A, when performing plasma processing on the processing object 6, first, the discharge gas G is supplied into the insulating tube 11c from a gas supply unit (not shown). Next, in the supply state of the discharge gas G, the high-frequency power source 2 starts outputting the high-frequency signal S1 to the plasma generator 3A. The high frequency signal S1 output from the high frequency power source 2 is supplied from the power supply position A to the radiator 14 through the power supply conductor 13 and the like. As a result, the radiator 14 defined by the length L1 (λ / 4 as an example) with respect to the wavelength λ of the high-frequency signal S1 operates as a resonance monopole. Thus, the plasma P is generated in a region located near the tip of the radiator 14 inside the insulating tube 11c where the discharge gas G in which the electric field intensity becomes maximum near the tip and the plasma is easily generated exists. Further, the plasma P extends along the flow of the discharge gas G and is radiated from the end portion (lower end portion in FIG. 3) of the insulating tube 11c to the object 6 to be processed. Thereby, the processing object 6 is surface-treated by the plasma P emitted from the housing 11.

  Also in this plasma processing apparatus 1A, the basic configuration of the casing 11, the radiator 14, and the power supply conductor 13 (the configuration that becomes an inverted F-shaped antenna) is the same as that of the plasma processing apparatus 1, and thus the generated plasma P Thus, even if the apparent length (electric length) of the radiator 14 changes before and after the generation of the plasma, the alignment state can be maintained both before and after the generation of the plasma P. Moreover, since the diameter of the plasma P can be defined by the inner diameter of the insulating tube 11c, it is possible to surface-treat only a narrow range on the surface of the processing object 6 by reducing the inner diameter of the insulating tube 11c.

  In this plasma processing apparatus 1A, the insulating tube 11c is made to function as a supply tube for the discharge gas G by inserting the insulating tube 11c through the through hole 22 and the cylindrical radiator 14, but FIG. As shown, a supply pipe 7 is separately provided as in the plasma processing apparatus 1B, a discharge gas G is supplied from the supply pipe 7 into a cylindrical radiator 14, and an insulating pipe 11c is provided near the tip of the radiator 14. It is also possible to configure the plasma generator 3B by attaching In this case, the insulating tube 11c may be attached to the inner peripheral surface near the tip of the radiator 14, or may be attached to the outer peripheral surface. In this example, as an example, the insulating tube 11 c is attached with the outer peripheral surface of the insulating tube 11 c in close contact with the inner peripheral surface of the radiator 14. By this plasma processing apparatus 1B, plasma P is generated in the vicinity of the tip of the radiator 14 in the insulating tube 11c, and the end of the insulating tube 11c (the end on the open end side of the cylindrical body 11a). The plasma P can be radiated to the object 6 to be processed from the end portion which is flush with the plasma processing apparatus 1A, and the same effect as the plasma processing apparatus 1A can be obtained. In addition, about the structure same as plasma processing apparatus 1A, the same code | symbol was attached | subjected and the overlapping description was abbreviate | omitted.

  Further, in each of the plasma processing apparatuses 1, 1A, 1B described above, the insulating tube 11c is disposed in the cylindrical body 11a, and the plasma P is generated near the tip of the radiator 14 inside the insulating tube 11c. Although the structure which makes the processed plasma P radiate | emitted to the process target body 6 mounted on the table 4 was employ | adopted, the process target body 6 is a tubular shape, and the internal peripheral surface becomes an object site | part of a plasma process. In this case, as in the plasma processing apparatus 1C shown in FIG. 6, the tubular processing object 6 is inserted into the closing plate 11b and the cylindrical radiator 14, and the processing object 6 is supplied with the discharge gas G. By functioning also as a tube, it becomes possible to process the inner peripheral surface of the object 6 to be processed with the plasma P on the insulating tube 11c by the plasma processing apparatus 1C.

  Hereinafter, the plasma processing apparatus 1C will be described with reference to FIG. In addition, about the structure same as plasma processing apparatus 1A, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  This plasma processing apparatus 1C has substantially the same configuration as the plasma processing apparatus 1A, and only the plasma generator 3C is different. As shown in FIG. 6, the plasma generating unit 3C of the plasma processing apparatus 1C has a configuration in which only the insulating tube 11c is omitted from the plasma generating unit 3A of the plasma processing apparatus 1A.

  Next, the operation of the plasma processing apparatus 1 </ b> C will be described. In the plasma processing apparatus 1 </ b> C, when the plasma processing is performed on the tubular processing object 6, first, the processing object 6 is moved to the through-hole 22 and the cylindrical radiator 14. Insert. Next, supply of the discharge gas G from the gas supply unit (not shown) into the processing object 6 is started. Next, in the supply state of the discharge gas G, the high-frequency power source 2 starts outputting the high-frequency signal S1 to the plasma generator 3. Thereby, similarly to the plasma processing apparatus 1A, the radiator 14 operates as a resonance monopole, the electric field intensity is maximized in the vicinity of the tip thereof, and the processing object 6 in which the discharge gas G that easily generates plasma exists. Inside, the plasma P is generated in a region located near the tip of the radiator 14. In this state, the processing object 6 is transferred from the through hole 22 side to the radiator 14 as an example. Thereby, the inner peripheral surface of the processing object 6 is sequentially subjected to plasma processing by the plasma P generated in the processing object 6.

  Also in this plasma processing apparatus 1C, the basic configuration of the casing 11, the radiator 14, and the power supply conductor 13 (the configuration that becomes an inverted F-shaped antenna) is the same as the plasma processing apparatuses 1, 1A, and 1B. Therefore, even if the apparent length (electrical length) of the radiator 14 is changed before and after the generation of the plasma by the generated plasma P in the same manner as each of the plasma processing apparatuses 1 described above, The alignment state can be maintained both after the occurrence. Therefore, it is possible to surface-treat the inner surface of the processing target tube while sufficiently improving the power efficiency of the plasma processing.

1 is a configuration diagram of a plasma processing apparatus 1 (a cross-sectional view taken along a central axis X for a housing 11). FIG. 2 is a cross-sectional view taken along line W1-W1 in FIG. 1 (a cross-sectional view excluding the coaxial connector 12). 1 is a configuration diagram of a plasma processing apparatus 1A (a cross-sectional view taken along a central axis X for a housing 11). FIG. 4 is a cross-sectional view taken along line W2-W2 in FIG. 3 (a cross-sectional view excluding the coaxial connector 12). It is a block diagram (it is sectional drawing in alignment with the central axis X about the housing | casing 11) of the plasma processing apparatus 1B. It is a block diagram (Cross sectional view along the central axis X about the housing | casing 11) of 1 C of plasma processing apparatuses. It is a characteristic view of VSWR before and after the plasma generation measured about the plasma processing apparatus 1 and the conventional plasma processing apparatus.

Explanation of symbols

1, 1A, 1B, 1C Plasma processing apparatus 2 High frequency power source 3, 3A, 3B, 3C Plasma generation unit 6 Processed object 11 Housing 11b Blocking plate 13 Feeding conductor 14 Radiator A Feeding position G Discharge gas L2 Feeding position A Predetermined distance to P Plasma S1 High frequency signal

Claims (3)

A cylindrical casing in which a ground potential is applied and one end is closed by a closing plate and the other end is formed as an open end, and the cylinder length direction of the casing is formed on the inner surface of the closing plate And a rod-shaped radiation conductor erected so as to extend along the line, and the radiation conductor is supplied in the state where the plasma discharge gas is supplied in the vicinity of the tip on the open end side of the radiation conductor. A plasma processing apparatus for generating plasma in the vicinity of the tip by radiating a high-frequency signal,
A plasma processing apparatus, comprising: a power supply conductor that is connected to a power supply position that is a predetermined distance away from a base end portion fixed to the blocking plate in the radiation conductor and supplies the high-frequency signal to the radiation conductor. The radiation conductor is formed in a cylindrical shape,
Comprising an insulating tube disposed in the radiation conductor in a state protruding from the tip of the radiation conductor;
The plasma processing apparatus according to claim 1, wherein the plasma discharge gas is supplied to the vicinity of the tip of the radiation conductor by the insulating tube, and the plasma is generated in the vicinity of the tip in the insulating tube. The radiation conductor is formed in a cylindrical shape,
The blocking plate is formed with a through hole communicating with the inside of the radiation conductor.
The plasma discharge gas is supplied to the vicinity of the tip of the radiation conductor by a processing target tube inserted in the through hole and the radiation conductor, and the plasma is generated in the vicinity of the tip in the processing target tube. The plasma processing apparatus according to claim 1.

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