Impedance matching device

Abstract

Because high voltage is generated in the first variable capacitor device connected to the main circuit, a variable capacitor with high voltage resistance is required, which tends to increase the size of the device and thus the cost. [Solution] The impedance matching device 1 is provided with a sensing device 11, a coil 20, and a fixed capacitor 16 in the main system 15A, and a variable capacitor 14A in the sub-system 15B which connects the input terminal of the coil 20 to ground. The variable reactor device 10 is positioned opposite the open end 21 of the winding portion 23 of the coil 20, and is arranged in a range where a magnetic flux F is formed by the alternating current supplied to the coil 20, and further comprises a metal shielding plate 30 that shields a portion of the magnetic flux F, and a moving mechanism 40 that moves the shielding plate 30 in a direction that changes the amount of magnetic flux F being shielded.

Description

[Technical Field]

[0001] The present invention relates to an impedance matching device. [Background Art]

[0002] As a technique of this type, for example, Patent Document 1 proposes an impedance matching device described below. In this impedance matching device, a directional coupler (sensing device), a first variable capacitor device, and a reactor are provided in order from the input terminal side in a main line that connects an input terminal connected to a high-frequency power supply and an output terminal connected to a load. Furthermore, a second variable capacitor device is provided in a sub-line that connects the ground to the main line between the input terminal and the first variable capacitor device. The control device matches the impedance between the high-frequency power supply and the load by controlling the motors of the first variable capacitor device and the second variable capacitor device. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2006-166412 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] However, in the impedance matching device disclosed in Patent Document 1, a high voltage is generated in the first variable capacitor device connected to the main line, so a variable capacitor having high withstand voltage is required, which tends to increase the size and cost of the device.

[0005] The present invention has been made in view of such circumstances, and an object of the present invention is to provide an impedance matching device that can suppress an increase in size of the device and can be manufactured at a lower cost. [Means for Solving the Problem]

[0006] In view of the above problems, the impedance matching device according to the present invention is an impedance matching device provided between a high-frequency power supply and a load, which performs an impedance matching operation to match the impedance between the high-frequency power supply and the load. The impedance matching device comprises a variable capacitor device comprising at least a first motor and a variable capacitor, which drives the first motor to change the capacitance of the variable capacitor; a variable reactor device comprising at least a second motor and a coil, which drives the second motor to change the inductance of the coil; a fixed capacitor having a constant capacitance; a sensing device positioned on the input terminal side of a main system connecting an input terminal connected to the high-frequency power supply and an output terminal connected to the load, which senses electrical information at that position; and a control device that controls the first motor and the second motor based on the electrical information in order to perform the impedance matching operation. The main system is provided with the sensing device, the coil, and the fixed capacitor. The sub-system connecting the input terminal of the coil to ground is provided with the variable capacitor. The variable reactor device further comprises a metal shielding plate positioned opposite the open end of the coil winding portion, within the range in which a magnetic flux is formed by the alternating current supplied to the coil, and which shields a portion of the magnetic flux; and a moving mechanism for moving the shielding plate in a direction that changes the amount of the magnetic flux being shielded.

[0007] The variable reactor device used in this invention has a structure that adjusts the amount of shielding of the magnetic flux flowing through the coil by moving a shielding plate. Therefore, despite the small size of the inductance adjustment mechanism, the inductance adjustment range is large. In addition, it is easy to increase the current value flowing through the coil by increasing the diameter of the coil. In other words, a variable reactor capable of handling large currents can be realized by increasing the diameter of the coil windings and using water cooling, as the inductance adjustment range is wide.

[0008] Therefore, even if the system is configured with a variable reactor device consisting of a coil and a shielding plate instead of the first variable capacitor device previously present in the main system, and with a fixed capacitor instead of the coil previously present in the main system, it is possible to achieve the same matching range as the conventional technology.

[0009] Furthermore, in this invention, the inductance adjustment mechanism (shielding plate and moving mechanism) of the variable reactor device has a simple structure, allowing it to be implemented at a low cost. In addition, since variable capacitors are very expensive, significant cost reductions can be achieved by replacing them with fixed capacitors.

[0010] In a more preferred embodiment, the main system is provided with the sensing device, the coil, and the fixed capacitor in that order from the input terminal side, and the shielding plate is located on the input terminal side of the coil.

[0011] According to this embodiment, by arranging the adjustment mechanism (shielding plate and moving mechanism) on the input terminal side, it becomes possible to manufacture the variable reactor device with a low voltage resistance, thereby enabling miniaturization of the variable reactor device.

[0012] Furthermore, since fixed capacitors are located on the output terminal side in the main system, they require higher current and voltage resistance than those located on the input terminal side. However, in this configuration, a variable mechanism for changing capacitance is unnecessary, so even with high current and voltage resistance, the use of fixed capacitors allows for miniaturization. As a result, the overall size of the impedance matching device can be reduced.

[0013] In a more preferred embodiment, the shielding plate is electrically connected to ground. In this embodiment, eddy currents are generated in the shielding plate that shields the magnetic flux, and these eddy currents are directed towards ground, allowing the shielding plate to stably maintain its ability to shield the magnetic flux.

[0014] In a more preferred embodiment, the surface of the shielding plate is coated with an electrically insulating resin material. In this embodiment, the insulating material can prevent discharge between the shielding plate and components arranged around the variable reactor device.

[0015] In a more preferred embodiment, the moving mechanism is a mechanism that moves the shielding plate in a direction intersecting the direction in which the magnetic flux flows within the coil, such that the area over which the shielding plate blocks the magnetic flux changes.

[0016] In this embodiment, a shielding plate can shield a portion of the magnetic flux passing through the coil. By moving such a shielding plate with a moving mechanism to adjust the area that the shielding plate blocks, the amount of magnetic flux passing through the coil can be adjusted. As a result, by directly adjusting the amount of magnetic flux passing through the coil, the apparent inductance of the coil can be adjusted over a wider range of adjustment.

[0017] In a more preferred embodiment, the moving mechanism is a mechanism that rotates the shielding plate around a rotation axis parallel to the axis of the winding portion.

[0018] According to this embodiment, by making the moving mechanism a rotating mechanism, the shielding plate is moved by the moving mechanism in a simpler structure, and the area that the shielding plate blocks the magnetic flux is change Because this allows for impedance adjustment to be performed in a shorter amount of time.

[0019] In a more preferred embodiment, the variable reactor device further comprises a support for the coil in a fixed state, the support having an insulating core portion inserted through the winding portion, the core portion having a protruding portion extending from the open end of the winding portion, the moving mechanism being fixed to the protruding portion, and the shielding plate being supported by the support via the moving mechanism.

[0020] According to this aspect, by fixing the moving mechanism to the protruding portion, there is no need to separately support the moving mechanism. In particular, when connecting the moving mechanism to the ground, it is only necessary to connect the moving mechanism to the ground via wiring or the like.

[0021] In a more preferred aspect, the moving mechanism is a mechanism that moves the shielding plate relative to the open end so as to adjust the distance between the open end and the shielding plate.

[0022] According to this aspect, part of the magnetic flux passing through the coil can be shielded by the shielding plate. By moving such a shielding plate via the moving mechanism to adjust the distance between the open end of the coil and the shielding plate, the amount of magnetic flux passing through the coil is adjusted. As a result, by directly adjusting the amount of magnetic flux passing through the coil, the apparent inductance of the coil can be adjusted with a wider range of adjustment allowance.

Effects of the Invention

[0023] According to the present invention, an increase in size of the device can be suppressed, and the device can be manufactured at lower cost.

Brief Description of Drawings

[0024] [Figure 1] It is a configuration diagram of a high-frequency power supply system to which an impedance matching device according to a first embodiment of the present invention is applied, and a circuit block diagram of the impedance matching device. [Figure 2A] It is a schematic perspective view of the variable reactor device shown in FIG. 1. [Figure 2B] It is a view of the variable reactor device shown in FIG. 2A as viewed from the side. [Figure 2C] It is an exploded perspective view of the rotating mechanism shown in FIG. 2A. [Figure 2D] It is an explanatory diagram for explaining the operation of the rotating mechanism shown in FIG. 2C. [Figure 3A] It is a schematic perspective view of a variable reactor device of an impedance matching device according to a second embodiment. [Figure 3B]Figure 3A shows a side view of the variable reactor device. [Figure 3C] Figure 3A is an exploded perspective view of the rotating mechanism. [Figure 3D] Figure 3C is an explanatory diagram illustrating the operation of the rotating mechanism shown. [Figure 4] This is a schematic perspective view of a variable reactor device for impedance matching according to the third embodiment. [Figure 5A] This is a schematic perspective view of a variable reactor device for impedance matching according to a fourth embodiment of the present invention. [Figure 5B] Figure 5A shows a side view of the variable reactor device. [Figure 5C] Figure 5A is an exploded perspective view of the moving mechanism. [Figure 6] This shows the configuration of a high-frequency power supply system to which a conventional impedance matching device is applied, and a circuit block diagram of the impedance matching device. [Figure 7] (a) is a graph showing the relationship between resistance and reactance using the impedance matching device shown in Figure 6. (b) is a graph showing the relationship between resistance and reactance using the impedance matching device shown in Figure 1. [Modes for carrying out the invention]

[0025] The impedance matching devices of the first to fourth embodiments according to the present invention will be described below with reference to Figures 1 to 7.

[0026] [First Embodiment] 1. Overall configuration of impedance matching device 1 Figure 1 shows the configuration of a high-frequency power supply system to which the impedance matching device 1 according to the first embodiment of the present invention is applied, and a circuit block diagram of the impedance matching device 1.

[0027] As shown in Figure 1, in the embodiment described below, the impedance matching device 1 is installed between the high-frequency power supply 2 and the load 3 and is a device that performs impedance matching operations to match the impedance between the high-frequency power supply 2 and the load 3. The impedance matching device 1 has an input terminal 18 connected to the high-frequency power supply 2 and an output terminal 19 connected to the load 3. The frequency of the high-frequency power (frequency of the AC current) is, for example, about 1 MHz to 300 MHz.

[0028] The high-frequency power supply 2 is a device for supplying high-frequency power having the above-described frequency to the load 3. The high-frequency power supply 2 is connected to the input terminal 18 of the impedance matching device 1 via a transmission line, for example, a coaxial cable. The impedance matching device 1 is connected to a load connection section made of a shielded copper plate, for example, to suppress electromagnetic wave leakage, and the load 3 is connected to the load connection section. The load 3 is a plasma processing device for processing workpieces such as semiconductor wafers and liquid crystal substrates using methods such as etching and CVD. Various processing processes are performed in the plasma processing device according to the processing purpose of the workpiece.

[0029] The impedance matching device 1 comprises a variable capacitor device 14, a variable reactor device 10, and a fixed capacitor 16 having a constant capacitance. The variable capacitor device 14 comprises at least a first motor 14B and a variable capacitor 14A. The variable capacitor device 14 drives the first motor 14B to change the capacitance of the variable capacitor 14A. Specifically, based on a control signal sent from the control device 12 (described later), the variable capacitor device 14 uses the first motor 14B to change the area of ​​the counter electrode (not shown) of the variable capacitor 14A, thereby changing the capacitance of the variable capacitor 14A.

[0030] The variable reactor device 10 includes at least a second motor 10B and a coil 20. The variable reactor device 10 drives the second motor 10B to change the inductance of the coil 20. The variable reactor device 10 also changes the amount of magnetic flux formed by the coil 20 when energized, and thus changes the inductance of the coil 20, by moving the shielding plate 30, which will be explained in Figure 2 and later, using the second motor 10B based on a control signal sent from the control device 12, which will be described later.

[0031] The impedance matching device 1 further includes a sensing device 11. The sensing device 11 is located on the input terminal 18 side of the main system 15A, which connects the input terminal 18 connected to the high-frequency power supply 2 and the output terminal 19 connected to the load 3. The sensing device 11 senses electrical information at this location. The sensing device 11 can sense current and voltage information at this location, or forward wave voltage and reflected wave voltage at this location, as electrical information. When sensing current and voltage information at this location, for example, a current detector and a voltage detector are used. When sensing forward wave voltage and reflected wave voltage at this location, a directional coupler is used.

[0032] The impedance matching device 1 further includes a control device 12 that controls the first motor 14B and the second motor 10B based on electrical information sensed by the sensing device 11 in order to perform matching operation.

[0033] Here, the control device 12 calculates the input impedance of the impedance matching device 1, that is, the load-side impedance or reflection coefficient as seen from the input terminal 18 of the impedance matching device 1 to the load 3 side, based on the electrical information.

[0034] When sensing current and voltage information in the sensing device 11, the control device 12 calculates the phase difference between the current and voltage, and calculates the load-side impedance or reflection coefficient based on the current, voltage, and the phase difference between the two. When sensing forward wave voltage and reflected wave voltage in the sensing device 11, the control device 12 calculates the load-side impedance or reflection coefficient based on the forward wave voltage and reflected wave voltage. Since load-side impedance and reflection coefficient are mutually convertible, either one can be calculated.

[0035] The control device 12 estimates the capacitance of the variable capacitor 14A and the inductance of the coil 20, which are impedance-variable elements, by acquiring the adjustment positions of the variable capacitor device 14 and the variable reactor device 10. The first motor 14B is equipped with a function to output the adjustment position of the variable capacitor device 14, and the second motor 10B is equipped with a function to output the adjustment position of the variable reactor device 10.

[0036] The control device 12 adjusts the capacitance of the variable capacitor 14A and the inductance of the coil 20 using the calculated load-side impedance or reflection coefficient so that the reflected wave power returning from the load 3 to the high-frequency power supply 2 is reduced. To this end, the control device 12 gives a drive command to the first motor 14B to adjust the capacitance of the variable capacitor 14A. The control device 12 also gives a drive command to the second motor 10B to adjust the inductance of the coil 20. In order to perform the matching operation described above, the control device 12 may use the estimated capacitance of the variable capacitor 14A and the inductance of the coil 20.

[0037] Furthermore, the impedance matching device 1 may include a storage device 13 connected to the control device 12. The storage device 13 stores data for the S-parameters (Scattering Parameters) of the impedance matching device 1 at each adjustment position of the variable capacitor device 14 (variable capacitor 14A) and the variable reactor device 10 (coil 20). The storage device 13 may also store T-parameters (Transmission Parameters) converted from the S-parameters.

[0038] The specific functions of these sensing devices 11 and control devices 12 are disclosed, for example, in Japanese Patent Publication No. 5-63604 and Japanese Patent Publication No. 2006-166412 filed by the applicant, so their details will not be explained here.

[0039] As described above, the impedance matching device 1 includes a main system 15A that connects the input terminal 18 and the output terminal 19, and a secondary system 15B that branches off from the main system 15A and is connected to ground. The main system 15A is provided with a sensing device 11, a coil 20, and a fixed capacitor 16. More specifically, the main system 15A is provided with the sensing device 11, the coil 20, and the fixed capacitor 16 in that order from the input terminal 18 side. More specifically, the secondary system 15B is a system that connects the input terminal of the coil 20 to ground. The secondary system 15B is provided with the variable capacitor 14A of the variable capacitor device 14.

[0040] 2. About the variable reactor device 10 The variable reactor device 10 will be described below with reference to Figures 2A to 2D. Figure 2A is a schematic perspective view of the variable reactor device 10 shown in Figure 1. Figure 2B is a side view of the variable reactor device 10 shown in Figure 2A. Figure 2C is an exploded perspective view of the rotating mechanism shown in Figure 2A. Figure 2D is an explanatory diagram for illustrating the operation of the rotating mechanism shown in Figure 2C.

[0041] The variable reactor device 10 according to the first embodiment is, for example, a device mounted on an impedance matching device 1, and as shown in Figures 2A and 2B, it is equipped with a coil 20 that is part of the main system 15A.

[0042] The variable reactor device 10 according to this embodiment includes a unit body 10A having at least a coil 20, a shielding plate 30, a moving mechanism 40, and a support 50, and a second motor 10B for operating the moving mechanism 40. As shown in Figures 2A and 2B, the coil 20 is a conductor made of, for example, copper or aluminum, and the conductor is made of enameled wire coated with enamel, but the conductor may also be flat rectangular copper wire without coating, and is not limited to this. In this embodiment, the coil 20 is made of a round wire with a circular cross-section, but it may also be made of flat rectangular copper wire or copper pipe, etc., with a rectangular cross-section or an internal hollow core.

[0043] The coil 20 is an air-core coil having a spirally wound winding portion 23. The winding portion 23 is air-core, but a columnar body (for example, a cylindrical body) made of insulating resin may be inserted into it. Open ends 21 and 22 are formed on both sides of the winding portion 23. In this embodiment, the winding portion 23 is a spirally wound portion wound in a cylindrical shape, but it may also be a spirally wound portion wound in a rectangular prism shape, such as a square prism or a hexagonal prism.

[0044] An input terminal 25A is connected to one end 24A extending from the winding portion 23 of the coil 20, and an output terminal 25B is connected to the other end 24B. An alternating current of the above frequency is passed through the coil 20 between the input terminal 25A and the output terminal 25B, and a magnetic flux F is formed in the winding portion 23 by the passage of this alternating current.

[0045] The coil 20 is fixed while being supported by the support 50. Specifically, the support 50 includes a mounting base 51. The mounting base 51 has a metal portion 51A of a conductive plate made of a metal material such as copper or aluminum.

[0046] In this embodiment, the metal part 51A is connected to ground. On the surface of the metal part (conductive plate) 51A, an insulating part 51B is formed on the surface facing the side of the winding portion 23 of the coil 20, made of an electrically insulating insulating material such as a resin material or a ceramic material. The support 50 has a columnar body 57 rising from the insulating part 51B of the mounting base 51 and a cylindrical core material portion 55 inserted through the winding portion 23 of the coil 20. The columnar body 57 and the core material portion 55 are made of an electrically insulating insulating material such as a resin material. The core material portion 55 is fixed to the columnar body 57 in a cantilevered state at its end face.

[0047] In this way, even when a high-voltage alternating current is passed through the coil 20, discharge from the winding portion 23 can be prevented because the columnar body 57, the core material portion 55, and the insulating portion 51B are made of electrically insulating materials.

[0048] The shielding plate 30 is a plate-shaped member that shields a portion of the magnetic flux F formed by the coil 20 when alternating current is passed through it. As shown in Figure 2C, in this embodiment, the shielding plate 30 is disc-shaped, and tabs 31 are formed on the periphery of the shielding plate 30. The shielding plate 30 is made of a metal material such as copper, aluminum, stainless steel, or cast iron. As will be described later, from the viewpoint of reducing the occurrence of induction heating due to the magnetic flux F when shielding the magnetic flux F, it is preferable that this metal material be a non-magnetic material such as copper or aluminum. As described above, the main system 15A is provided with a sensing device 11, a coil 20, and a fixed capacitor 16 in that order from the input terminal 18 side. In this embodiment, the shielding plate 30 is located on the input terminal 25A side of the coil 20.

[0049] In this embodiment, the shielding plate 30 is positioned opposite one open end 21 of the winding portion 23 of the coil 20, within the range where a magnetic flux F is formed by the alternating current supplied to the coil 20. Specifically, the shielding plate 30 is positioned opposite the end face of the core material portion 55 of the support 50, with a gap between it and the core material portion 55. The surface of the shielding plate 30 is covered with an electrically insulating resin material 32. In this embodiment, the resin material 32 is applied to the surface of the shielding plate 30 opposite to the surface facing one open end 21 of the winding portion 23. The resin material 32 prevents discharge between the shielding plate 30 and the members arranged around it.

[0050] The moving mechanism 40 is a mechanism that moves the shielding plate 30 in a direction that changes the amount of magnetic flux F being shielded. Specifically, the shielding plate 30 is moved in a direction intersecting the direction in which the magnetic flux F flows within the winding portion 23, so that the area over which the shielding plate 30 shields the magnetic flux F changes. Specifically, the surface of the shielding plate 30 is perpendicular to the axis CL of the winding portion 23, and the moving mechanism 40 is a rotation mechanism that rotates the shielding plate 30 around a rotation axis RL that is parallel to the axis CL of the winding portion 23. Here, "the area over which the shielding plate 30 shields the magnetic flux F" refers to the area where the internal region of the open end 21 of the winding portion 23 and the shielding plate 30 overlap, as viewed from a direction along the axis CL of the winding portion 23.

[0051] In the series of embodiments including Figures 3A and 3B, the distance between the shielding plate 30 and the open end 21 of the coil 20 is relatively long for the convenience of drawing the diagrams. In reality, the shielding plate 30 and the open end 21 of the coil 20 are placed close together with some space between them. Assuming that there is no discharge between the shielding plate 30 and the open end 21 of the coil 20, the shorter the distance between the shielding plate 30 and the open end 21 of the coil 20, the greater the adjustment range for the amount of magnetic flux F that the shielding plate 30 shields (i.e., the area that the shielding plate shields from the magnetic flux). Therefore, the positional relationship between the shielding plate 30 and the coil 20 shown in the second embodiment shown in Figures 3A and 3B, and the positional relationship between the shielding plate 30 and the coil 20 shown in the third embodiment shown in Figure 4, which will be described later, are similar.

[0052] The moving mechanism 40 has a metal support column 45 erected on the metal portion 51A of the mounting base 51, and a clamping portion 46 is formed at the tip of the support column 45 for clamping the tab 31 of the shielding plate 30. As shown in Figure 2C, the clamping portion 46 has an insertion hole through which a connecting shaft 47 is inserted. The connecting shaft 47 is fitted into the tab 31 with the shaft inserted through the through hole 31a formed in the tab 31. The tab 31 is rotatably positioned around the connecting shaft 47 with the shaft inserted into the space 46b formed in the clamping portion 46.

[0053] In this way, as shown in Figures 2A and 2B, the moving mechanism 40 is mounted on the mounting base 51 by the support columns 45. Specifically, the unit body 10A has the coil 20 fixed and the coil 20 is supported by the support 50 (core material portion 55), while the shielding plate 30 is supported by the support 50 (mounting base 51) via the support columns 45 of the moving mechanism 40.

[0054] Furthermore, the shielding plate 30 is electrically connected to the metal portion 51A of the mounting base 51 via the support column 45. As mentioned above, the metal portion 51A is connected to ground, and as a result, the shielding plate 30 is electrically connected to ground. As will be described later, when the magnetic flux is shielded, eddy currents are generated in the shielding plate 30, and these eddy currents can be passed from the shielding plate 30 to the metal portion 51A. This allows the shielding plate 30 to stably maintain its ability to shield the magnetic flux.

[0055] As shown in Figure 2B, the second motor 10B has a motor body 10a and an output shaft 10b extending from the motor body 10a. The connecting shaft 47 and the output shaft 10b are connected via a coupling 48. This allows the connecting shaft 47 to rotate according to the rotation angle of the second motor 10B.

[0056] In this embodiment, the second motor 10B is connected to the wiring 10 connected to the motor body 10a. c It has wiring 10 cThe second motor 10B is connected to the control device 12. Driven by the power (control signal) from the control device 12, the second motor 10B is driven to a desired number of rotations (rotation angle) and controls the rotational movement of the shielding plate 30 fitted to the connecting shaft 47. With this control device 12, while AC current is supplied to the coil 20, the shielding plate 30 can be moved by the moving mechanism 40 to change the area that the shielding plate 30 blocks from the magnetic flux F.

[0057] In this way, by controlling the second motor 10B with the control device 12, the shielding plate 30 can shield a portion of the magnetic flux passing through the coil 20. Specifically, by moving the shielding plate 30 with the moving mechanism 40 and changing the area over which the shielding plate 30 blocks the magnetic flux F, the amount of magnetic flux passing through the coil 20 can be adjusted. As a result, by directly adjusting the amount of magnetic flux passing through the coil 20, the apparent inductance of the coil 20 can be adjusted over a wider range of adjustment.

[0058] In particular, by making the moving mechanism 40 a rotating mechanism, the shielding plate 30 can be rotated by the moving mechanism 40 with a simpler structure, thereby changing the area over which the shielding plate 30 blocks the magnetic flux F. As a result, by directly adjusting the amount of magnetic flux passing through the coil 20, the apparent inductance of the coil 20 can be adjusted in a shorter time with a wider adjustment range, and the impedance of the impedance matching device 1 can be adjusted in a shorter time.

[0059] For example, if you want to increase the inductance of the coil 20 from the position of the shielding plate 30 shown in Figure 2D, rotate the shielding plate 30 counterclockwise so that the magnetic flux of the coil 20 increases. This reduces the area in which the open end 21 of the axis CL of the winding portion 23 overlaps with the shielding plate 30, thereby increasing the magnetic flux of the coil 20. On the other hand, if you want to decrease the inductance of the coil 20 from the position of the shielding plate 30 shown in Figure 2D, rotate the shielding plate 30 clockwise so that the magnetic flux of the coil 20 decreases. This increases the area in which the open end 21 of the axis CL of the winding portion 23 overlaps with the shielding plate 30, thereby decreasing the magnetic flux of the coil 20.

[0060] Thus, the variable reactor device 10 has a structure that adjusts the amount of shielding of the magnetic flux F flowing through the coil 20 by moving the shielding plate 30. Therefore, despite the small size of the inductance adjustment mechanism, the inductance adjustment range is large. In addition, it is easy to increase the current value flowing through the coil by increasing the diameter of the coil. In other words, a variable reactor capable of handling large currents can be realized by increasing the diameter of the coil windings and water cooling the coil 20, resulting in a wide inductance adjustment range.

[0061] Incidentally, as shown in Figure 6, the conventional impedance matching device 9 has a main circuit 15A connecting an input terminal 18 connected to a high-frequency power supply 2 and an output terminal 19 connected to a load 3, and in order from the input terminal 18 side, a sensing device 11 (for example, a directional coupler), a variable capacitor 16A of the first variable capacitor device 16C, and a coil 17 are provided. Furthermore, a sub-circuit 15B connecting the main circuit 15A between the input terminal 18 and the variable capacitor 16A to ground is provided with a variable capacitor 14A of the second variable capacitor device 14C. The control device 12 controls the motors 16B and 14B of the first variable capacitor device 16C and the second variable capacitor device 14C, respectively, to adjust the capacitance of the variable capacitor 14A and the variable capacitor 16A so that the reflected wave power returning from the load 3 side to the high-frequency power supply 2 is reduced.

[0062] Furthermore, the inductance adjustment mechanism (shielding plate 30 and moving mechanism 40) of the variable reactor device 10 has a simple structure and can be implemented at a low cost. In addition, since the first variable capacitor device 16C is very expensive, a significant cost reduction can be achieved by changing the first variable capacitor device 16C to a fixed capacitor 16.

[0063] By arranging the adjustment mechanism (shielding plate 30 and moving mechanism 40) on the input terminal 18 side, the variable reactor device 10 can be manufactured with a low voltage tolerance, thereby enabling miniaturization of the variable reactor device 10.

[0064] Furthermore, since the fixed capacitor 16 is located on the output terminal 19 side in the main system 15A, it requires a higher current and higher voltage rating than a capacitor located on the input terminal 18 side. However, in this embodiment, a variable mechanism for changing capacitance is unnecessary, so even if it requires a high current and high voltage rating, the fixed capacitor 16 can be miniaturized. As a result, the entire impedance matching device 1 can be miniaturized.

[0065] [Second Embodiment] The impedance matching device 1 according to the second embodiment of the present invention will be described below with reference to Figures 3A to 3D. Figure 3A is a schematic perspective view of the variable reactor device 10 of the impedance matching device 1 according to the second embodiment. Figure 3B is a side view of the variable reactor device 10 shown in Figure 3A. Figure 3C is an exploded perspective view of the rotating mechanism shown in Figure 3A. Figure 3D is an explanatory diagram for illustrating the operation of the rotating mechanism shown in Figure 3C.

[0066] The difference between the impedance matching device 1 of the second embodiment and that of the first embodiment lies in the structure of the variable reactor device 10, specifically in the shape of the shielding plate 30 and the structure of the core material portion 55 of the support 50. Therefore, components having the same function as in the first embodiment are denoted by the same reference numerals, and a detailed explanation of their configurations and the effects arising from them is omitted.

[0067] As shown in Figures 3A and 3B, in this embodiment, similar to the first embodiment, the support 50 has an insulating core material portion 55. The core material portion 55 is inserted through the winding portion 23 of the coil 20. Furthermore, an alternating current of the above frequency is passed through the coil 20 between the input terminal 25A and the output terminal 25B, and a magnetic flux F is formed in the winding portion 23 by the passage of this alternating current.

[0068] The core portion 55 has a protruding portion 55a that extends from the open end 21 of the winding portion 23. As shown in Figure 3C, a housing recess 59 for housing a semicircular shielding plate 30 is formed in the protruding portion 55a. In this embodiment, a semicircular shielding plate 30 is exemplified, but the shape of the shielding plate 30 is not particularly limited as long as it can shield magnetic flux. For example, the shielding plates 30 in the first embodiment described above, the third embodiment described later, and the fourth embodiment described later are also circular in shape, but this shape is not limited as long as it can shield magnetic flux. As shown in Figure 3B, when the shielding plate 30 is housed in the housing recess 59, a gap S is formed between the shielding plate 30 and the wall surface forming the housing recess 59. This allows for smooth movement of the shielding plate 30 and suppresses discharge within the shielding plate 30.

[0069] In this embodiment, as shown in Figure 3C, the moving mechanism 40 is fixed to the protruding portion 55a. Specifically, the moving mechanism 40 according to this embodiment has a clamping bracket 46A and a connecting shaft 47, and the clamping bracket 46A is fixed to the protruding portion 55a.

[0070] Specifically, the clamping bracket 46A has a through hole 46a through which the connecting shaft 47 is inserted. The connecting shaft 47 is rotatably inserted into the through hole 46a of the clamping bracket 46A with the tab 31 inserted into the space 46b formed in the clamping bracket 46A, and is fitted into the through hole 31a formed in the tab 31. The clamping bracket 46A has a mounting portion 46c that is attached to the protruding portion 55a of the core material portion 55. With the mounting portion 46c in contact with the protruding portion 55a, the fastener 91 is inserted into the through hole 46d formed in the mounting portion 46c, and the fastener 91 is fastened into the fastening hole 58 of the protruding portion 55a, thereby attaching the clamping bracket 46A to the protruding portion 55a. As a result, by fixing the moving mechanism 40 to the protruding portion 55a, there is no need to support the moving mechanism 40 separately. In particular, when connecting the mobile mechanism 40 to ground, the mobile mechanism 40 can be connected to ground via wiring 49 or the like.

[0071] With alternating current flowing through the coil 20, the shielding plate 30 can be moved by the moving mechanism 40, as shown in Figure 3D, to change the area that the shielding plate 30 blocks the magnetic flux F. To increase the inductance of the coil 20 from the position of the shielding plate 30 shown in Figure 3D, the shielding plate 30 should be rotated counterclockwise so that the magnetic flux of the coil 20 increases. On the other hand, to decrease the inductance of the coil 20 from the position of the shielding plate 30 shown in Figure 3D, the shielding plate 30 should be rotated clockwise so that the magnetic flux of the coil 20 decreases.

[0072] [Third Embodiment] The impedance matching device 1 according to the third embodiment of the present invention will be described below with reference to Figure 4. Figure 4 is a schematic perspective view of the variable reactor device 10 of the impedance matching device 1 according to the third embodiment of the present invention. The difference between the impedance matching device 1 of the third embodiment and that of the first embodiment is the structure of the moving mechanism 40. Therefore, components having the same function as in the first embodiment are denoted by the same reference numerals, and a detailed explanation of their configuration and the effects arising from it will be omitted.

[0073] In this embodiment, the moving mechanism 40 is a ball screw mechanism that linearly moves the shielding plate 30. Specifically, the moving mechanism 40 has a metal screw shaft 41A. One end of the screw shaft 41A is connected to the output shaft 10b of the second motor 10B via a coupling, and the other end of the screw shaft 41A is attached to the mounting base 51 via a metal bearing 41C. A metal nut portion (movable element) 41B is screwed onto the screw shaft 41A. The nut portion 41B is fixed to the periphery of the shielding plate 30. Furthermore, although not shown, the nut portion 41B is provided with a linear guide that guides the nut portion 41B along the axial direction of the screw shaft 41A.

[0074] In this way, when the output shaft 10b of the second motor 10B is rotated, the screw shaft 41A rotates, and the nut portion 41B moves linearly along the linear guide. This allows the shielding plate 30 to move linearly using the moving mechanism 40, thereby changing the area over which the shielding plate 30 blocks the magnetic flux F. As a result, by directly adjusting the amount of magnetic flux passing through the coil 20, the apparent inductance of the coil 20 can be adjusted over a wider range of adjustment.

[0075] [Fourth Embodiment] The impedance matching device 1 according to the fourth embodiment of the present invention will be described below with reference to Figures 5A to 5C. Figure 5A is a schematic perspective view of the variable reactor device 10 of the impedance matching device 1 according to the fourth embodiment. Figure 5B is a side view of the variable reactor device 10 shown in Figure 5A. Figure 5C is an exploded perspective view of the rotating mechanism shown in Figure 5A.

[0076] The impedance matching device 1 of the fourth embodiment differs from that of the first embodiment in the structure of the variable reactor device 10, specifically in the structure of the moving mechanism 40 and the support 50. Therefore, components having the same function as in the first embodiment are denoted by the same reference numerals, and a detailed explanation of their configuration and the effects arising from it is omitted.

[0077] As shown in Figures 5A to 5C, the support 50 has a mounting base 51 on which the coil 20 and the moving mechanism 40 are placed, and a support plate 53 that supports the moving mechanism 40. Insulating portion 51B is, tree Made from electrically insulating materials such as lipid materials or ceramic materials. Furthermore, the insulating portion 51B supports the side surface of the winding portion 23 of the coil 20. A pair of support blocks 54 are provided. The coil 20 is supported by the support blocks 54 to It is mounted on the support plate 53. The support plate 53 is a metal plate made of copper or aluminum and is erected from the metal part 51A of the mounting base 51. The tip of the support plate 53 is semicircular, and an insertion hole 53a is formed in the support plate 53.

[0078] The moving mechanism 40 is a mechanism that moves the shielding plate 30 in a direction that changes the amount of magnetic flux F being shielded. Specifically, the moving mechanism 40 is a mechanism that moves the shielding plate 30 relative to the open end 21 of the coil 20 so as to adjust the distance L between the open end 21 of the coil 20 and the shielding plate 30. The moving mechanism 40 has a metal moving shaft 41 to which the shielding plate 30 is attached. Specifically, as shown in Figure 5C, the moving shaft 41 has a shaft portion 41a with a male screw formed on its tip side, and the base end of the shaft portion 41a is connected to a coupling 48. The shielding plate 30 is a disc-shaped metal plate, and a metal screw portion 34, such as a nut, is formed on the surface of the shielding plate 30 opposite to the surface facing the winding portion 23 of the coil 20, which screws into the tip of the shaft portion 41a. The support plate 53 has an insertion hole 53a through which the movable shaft 41 is inserted while the movable shaft 41 is screwed into it. Furthermore, the surface of the shielding plate 30 is covered with an electrically insulating resin material 32. In this embodiment, the resin material 32 is applied to the surface of the shielding plate 30 that faces one of the open ends 21 of the winding portion 23. The resin material 32 prevents discharge between the coil 20 and the shielding plate 30. However, if such discharge can be prevented by the limiting members 42A and 42B described later, it is not necessary to provide the resin material 32 on the surface of the shielding plate 30.

[0079] The shielding plate 30 is electrically connected to the metal portion 51A of the mounting base 51 via the movable shaft 41 and the support plate 53. Since the metal portion 51A is connected to ground, the shielding plate 30 is electrically connected to ground as a result. When the magnetic flux is shielded, eddy currents are generated in the shielding plate 30, and these eddy currents can be passed from the shielding plate 30 to the metal portion 51A. This allows the shielding plate 30 to stably maintain its ability to shield the magnetic flux.

[0080] As described above, a coupling 48 is attached to the base end of the movable shaft 41, which is connected to the output shaft 10b of the second motor 10B. Although not shown in the figures, the coupling 48 has a keyway that slidably engages with a key 41c formed on the side surface of the base end of the movable shaft 41. As a result, the rotation of the output shaft 10b of the second motor 10B causes the coupling 48 to rotate, and the movable shaft 41 can be moved along the keyway (specifically, along the axis of the winding portion 23 of the coil 20).

[0081] Furthermore, in this embodiment, a limiting member (limiting part) 42B is provided, which is screwed onto the shaft portion 41a of the movable shaft 41. The limiting member 42B is, for example, a nut. The limiting member 42B moves relative to the support plate 53 as the movable shaft 41 rotates, and the movement of the shielding plate 30 toward the winding portion 23 of the coil 20 is restricted by the limiting member 42B coming into contact with the support plate 53. This prevents the shielding plate 30 from coming too close to the winding portion 23 of the coil 20 when driven by the second motor 10B, and prevents discharge between the coil 20 and the shielding plate 30.

[0082] According to this embodiment, the shielding plate 30 can shield a portion of the magnetic flux passing through the coil 20 at a position opposite the open end 21 of the winding portion 23. By moving the shielding plate 30 with the moving mechanism 40 and adjusting the distance L between the open end 21 of the winding portion 23 and the shielding plate 30, the amount of magnetic flux passing through the coil 20 can be adjusted. As a result, by directly adjusting the amount of magnetic flux passing through the coil 20, the apparent inductance of the coil 20 can be adjusted over a wider range of adjustment.

[0083] Figure 7(a) is a graph showing the relationship between resistance and reactance for the conventional impedance matching device 9 shown in Figure 6. Figure 7(b) is a graph showing the relationship between resistance and reactance for the impedance matching device 1 shown in Figure 1. Figures 7(a) and 7(b) show the range of load impedances that can be matched (matching range). The impedance is expressed in the form R + jX. Here, R is the resistive component and X is the reactance component.

[0084] In the conventional impedance matching device 9 shown in Figure 6, with a 50Ω impedance in a matched state connected to the input terminal 18, the inductance L1 of the coil 17 shown in Figure 6 was kept constant, and the capacitance VC2 of the first variable capacitor device 16C (specifically, variable capacitor 16A) and the capacitance VC1 of the second variable capacitor device 14C (specifically, variable capacitor 14A) were varied from minimum to maximum within the range shown in Figure 7(a). Figure 7(a) shows the load impedance measured from the output terminal 19 at this time. Specifically, point A1 in Figure 7(a) is the impedance when capacitance VC1 is at its minimum and capacitance VC2 is at its minimum. Point B1 is the impedance when capacitance VC1 is at its minimum and capacitance VC2 is at its maximum. Point C1 is the impedance when capacitance VC1 is at its maximum and capacitance VC2 is at its maximum. Point D1 is the impedance when capacitance VC1 is at its maximum and capacitance VC2 is at its minimum.

[0085] On the other hand, in the impedance matching device 1 shown in Figure 1, with a 50Ω impedance (matched) connected to the input terminal 18, the capacitance C1 of the fixed capacitor was kept constant, and the inductance VL1 of the variable reactor device 10 and the capacitance VC1 of the variable capacitor device 14 (specifically, the variable capacitor 14A) were varied from minimum to maximum. Figure 7(b) shows the impedance measured from the output terminal 19 at this time. Specifically, point A2 in Figure 7(b) is the impedance when the inductance VL1 is minimum and the capacitance VC1 is minimum. Point B2 is the impedance when the inductance VL1 is maximum and the capacitance VC1 is minimum. Point C2 This is the impedance at which inductance VL1 is maximum and capacitance VC1 is maximum. Point D 2 This represents the impedance at minimum inductance VL1 and maximum capacitance VC1.

[0086] From the results in Figures 7(a) and 7(b), it can be seen that in this embodiment, a variable reactor device 10 consisting of a coil 20 and a shielding plate 30 is provided instead of the first variable capacitor device 16C (variable capacitor 16A) that was provided in the conventional main system 15A shown in Figure 6. Furthermore, in this embodiment, even if a fixed capacitor 16 is provided instead of the coil 17 that was provided in the conventional main system 15A, the same matching range as before can be achieved.

[0087] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various design modifications can be made without departing from the spirit of the invention as described in the claims. [Explanation of Symbols]

[0088] 1: Impedance matching device, 2: High-frequency power supply, 3: Load, 10, 10A: Variable reactor device, 10B: Second motor, 11: Sensing device, 12: Control device, 14: Variable capacitor device, 14A: Variable capacitor, 14B: First motor, 15A: Main system, 15B: Sub-system, 16: Fixed capacitor, 18: Input terminal, 19: Output terminal, 20: Coil, 21: Open end, 23: Winding section, 30: Shielding plate, 32: Resin material, 40: Moving mechanism, 50: Support, 55: Core material section, 55a: Protruding section, CL: Axis, F: Magnetic flux, L: Distance, RL: Rotation axis

Claims

1. An impedance matching device is provided between a high-frequency power supply and a load, and performs an impedance matching operation to match the impedance between the high-frequency power supply and the load, The impedance matching device is A variable capacitor device comprising at least a first motor and a variable capacitor, wherein the first motor drives the variable capacitor to change the capacitance of the variable capacitor, A variable reactor device comprising at least a second motor and a coil, which drives the second motor and changes the inductance of the coil, A fixed capacitor having a constant capacitance, A sensing device is positioned on the input terminal side of the main system connecting the input terminal connected to the high-frequency power supply and the output terminal connected to the load, and senses electrical information at that position. A control device that controls the first motor and the second motor based on the electrical information in order to perform the matching operation, It is equipped with, The main system is provided with the sensing device, the coil, and the fixed capacitor. The sub-system connecting the input terminal of the coil to ground is provided with the variable capacitor. The variable reactor device is, A metal shielding plate is positioned opposite the open end of the winding portion of the coil, within the range where a magnetic flux is formed by the alternating current supplied to the coil, and which shields a portion of the magnetic flux. The system further includes a moving mechanism for moving the shielding plate in a direction that changes the amount of magnetic flux being shielded, The impedance matching device is characterized in that the shielding plate is electrically connected to ground.

2. The impedance matching device according to claim 1, wherein the main system is provided with the sensing device, the coil, and the fixed capacitor in order from the input terminal side, and the shielding plate is located on the input terminal side of the coil.

3. The impedance matching device according to claim 1, characterized in that the surface of the shielding plate is coated with an electrically insulating resin material.

4. The impedance matching device according to any one of claims 1 to 3, wherein the moving mechanism is a mechanism that moves the shielding plate in a direction intersecting the direction in which the magnetic flux flows in the coil, such that the area over which the shielding plate blocks the magnetic flux changes.

5. The impedance matching device according to claim 4, characterized in that the moving mechanism is a mechanism that rotates the shielding plate around a rotation axis parallel to the axis of the winding portion.

6. The variable reactor device is, With the coil fixed, the system further includes a support that supports the coil. The support has a core material portion that is inserted through the winding portion and has insulating properties. The core portion has a protruding portion that extends from the open end of the winding portion, The aforementioned moving mechanism is fixed to the protruding portion, The impedance matching device according to claim 5, characterized in that the shielding plate is supported by the support via the moving mechanism.

7. The impedance matching device according to claim 1, characterized in that the moving mechanism is a mechanism for moving the shielding plate relative to the open end so as to adjust the distance between the open end and the shielding plate.

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