Voltage and current detection device and power meter

Abstract

To reduce a phase error between a detection voltage and a detection current due to a return current and to increase a degree of freedom in arrangement of a voltage / current detection sensor in the voltage / current detection sensor within an impedance matching device.SOLUTION: A voltage / current detection device and a wattmeter are voltage / current detection devices for detecting voltage and current of output of an impedance matching device provided between a high-frequency power supply and a load, and includes at least a set of paired voltage / current detection sensors for outputting each detection value of current detection by electromagnetic induction and voltage detection by spatial divided voltage, the respective paired voltage / current detection sensors are disposed symmetrically relative to an output current path in which an output current of the impedance matching device flows, sensor terminals of the respective voltage / current detection sensors are connected in series, and the total of the detection values of the voltage / current detection sensors is outputted with one end of the series connection as a detection end.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a voltage-current detection device that is attached to an impedance matching device and detects the voltage and current of the output of the impedance matching device, and a power meter.

Background Art

[0002] It is known that a voltage-current detection sensor is provided between an impedance matching device and a load, and the voltage-current detection sensor detects the voltage and current of the output of the impedance matching device, and calculates the power by obtaining the phase difference from the detected voltage and current.

[0003] In plasma analysis of a semiconductor manufacturing apparatus, an impedance matching device is provided between a high-frequency power source and a plasma load, the output of the impedance matching device is detected by a voltage-current detection sensor, and the power and impedance input to the plasma load are analyzed using the detected voltage and current (Patent Document 1).

[0004] Since the voltage-current detection sensor provided on the output side of the impedance matching device monitors the power considering the power loss of the impedance matching device, it is possible to more accurately analyze the power input to the plasma load.

[0005] In addition, since the plasma input power of a high-frequency system including a high-frequency generator can be monitored, in a configuration in which a plurality of high-frequency systems supply power to a plurality of semiconductor manufacturing apparatuses, a minute power difference generated between the powers input by each high-frequency generator to its respective plasma load can be analyzed. As a result, it is possible to monitor the machine differences between the products in each process of film formation, sputtering, and etching in each semiconductor manufacturing apparatus.

[0006] As current sensors, magnetic detection elements are known that measure current values ​​by detecting the magnetic field strength of the magnetic field generated by an electric current flowing through a conductor. Various magnetic detection elements are known to be used as current sensors, including fluxgate (FR) elements, Hall elements, magnetoresistive (MR) elements, and magnetoimpedance (MI) elements.

[0007] A known type of voltage sensor is a capacitive voltage sensor that detects voltage from the voltage divider point of series-connected capacitors (Patent Document 2).

[0008] Current sensors using magnetic detection elements suffer from errors due to noise magnetic fields. To reduce these errors and measure the current flowing through a conductor, a configuration has been proposed in which magnetic detection elements are positioned symmetrically in a direction perpendicular to the direction of the current being measured to cancel out the influence of the noise magnetic field (Patent Document 2). Another configuration has been proposed in which magnetic detection elements are arranged at equal angles on a circle in a plane perpendicular to the longitudinal direction of the conductor being measured, and magnetic field noise is removed by summing the measured values ​​(Patent Documents 3 and 4). [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Special Publication No. 2002-530856 [Patent Document 2] Japanese Patent Publication No. 2013-196861 [Patent Document 3] Japanese Patent Publication No. 2014-219320 [Patent Document 4] Japanese Patent Publication No. 2005-61980 [Overview of the project] [Problems that the invention aims to solve]

[0010] To measure the output current of an impedance matching device, it is necessary to install a voltage-current sensing sensor inside or near the impedance matching device. However, the requirements for installing such a voltage-current sensing sensor in an impedance matching device present problems such as errors in the detected phase due to noise magnetic fields, and limitations on the placement of the voltage-current sensing sensor.

[0011] Within an impedance matching device, a current path is formed between the load and the elements of the impedance matching device, through which a return current flows. The magnetic field generated by this return current acts as a noise magnetic field on the voltage-current detection sensor, causing a phase error between the detected current and the detected voltage detected by the voltage-current detection sensor. This phase error causes an error in the measurement of output power.

[0012] The patent documents mentioned above all concern technologies for detecting voltage or current, and do not disclose the fact that errors in the detection phase occur due to noise magnetic fields caused by return current.

[0013] Patent Document 3 discloses a method for reducing the influence of noise magnetic fields by arranging magnetic detection elements at equal angles on the circumference in a plane perpendicular to the longitudinal direction of the measurement conductor, adding up the current values ​​measured by each magnetic detection element to obtain a sum, and dividing by the number of magnetic detection elements to calculate the current value flowing through the measurement conductor. However, it does not disclose that the noise magnetic field is due to the return current.

[0014] Inside an impedance matching device, circuit elements such as LC circuits that constitute the matching unit are arranged. As impedance matching devices become smaller, there is less spatial room to place voltage and current detection sensors inside the device. Therefore, the spatial arrangement of magnetic detection elements, which are arranged at equal angles around the circumference, and the output ports of each magnetic detection element, becomes limited.

[0015] Therefore, conventional voltage-current detection devices have the problem that, in order to mount the voltage-current detection sensor inside or near the impedance matching device, a phase error occurs between the voltage and current due to the return current flowing inside the impedance matching device, and there is also the placement problem that the placement of the voltage-current detection sensor is physically restricted by the circuit elements of the impedance matching device.

[0016] Furthermore, in power meters that measure power values ​​using voltage, current, and phase values ​​detected by a voltage-current detection device equipped with an impedance matching device, there is a problem in that errors occur in the measured power value due to errors in the detected phase.

[0017] The present invention aims to solve the aforementioned conventional problems by reducing the phase error between the detected voltage due to the return current and the detected current in a voltage-current detection sensor inside an impedance matching device, and by increasing the degree of freedom in the arrangement of the voltage-current detection sensor inside the impedance matching device. Furthermore, the aim is to reduce errors in measured power values ​​caused by phase errors in voltage-current detection devices. [Means for solving the problem]

[0018] The voltage-current detection device of the present invention is a voltage-current detection device that detects the voltage and current of the output of an impedance matching device installed between a high-frequency power supply and a load, and comprises at least one pair of voltage-current detection sensors that output detection values ​​for current detection by electromagnetic induction and voltage detection by spatial voltage division.

[0019] Each pair of voltage-current sensing sensors comprises the following configurations: (a) arrangement, (b) magnetic field detection, (c) connection configuration, and (d) total output.

[0020] (a) Layout configuration Each pair of voltage-current detection sensors is arranged symmetrically with respect to an output current path through which the output current of the impedance matching device flows. Since at least one pair of voltage-current detection sensors can detect the voltage and current of the output of the impedance matching device, the degree of freedom in arranging the voltage-current detection sensors inside the impedance matching device can be increased, and they can be arranged in the surplus space for arranging circuit elements provided inside the impedance matching device.

[0021] (b) Magnetic field detection The magnetic fields detected by each pair of voltage-current detection sensors are a measured magnetic field generated by the output current and a noise magnetic field generated by a return current flowing inside the impedance matching device. The voltage-current detection sensor detects the combined magnetic field of the measured magnetic field and the noise magnetic field at the position where the voltage-current detection sensor is arranged. Among the magnetic fields detected by a pair of voltage-current detection sensors, the measured magnetic fields are in opposite directions to each other, while the noise magnetic fields are in the same direction. Therefore, the combined magnetic field detected by a pair of voltage-current detection sensors will increase or decrease by the amount of the noise magnetic field.

[0022] Furthermore, the return current generating the noise magnetic field is phase-advanced or phase-delayed with respect to the voltage depending on whether the load is a capacitive load or an inductive load. As a result, one of the detected currents obtained by the magnetic field detection of a pair of voltage-current detection sensors becomes phase-advanced, and the other becomes phase-delayed, resulting in a reverse-phase relationship with each other. Generally, when the load is a parallel-plate type plasma device, it becomes a capacitive load.

[0023] In this way, since the phases of the two detected currents obtained by the magnetic field detection of a pair of voltage-current detection sensors are in a reverse-phase relationship with each other, by combining the detected currents of the two voltage-current detection sensors, their phases cancel each other out, and the phase difference of the detected current is eliminated.

[0024] (c) Connection configuration The sensor terminals of all the voltage-current detection sensors included in the voltage-current detection device are connected in series, and one end of this series connection configuration is used as the detection end.

[0025] (d) Total output The detection outputs of all voltage and current detection sensors are summed from the detection terminal of the series connection, and the total output is output. By making one end of the series connection configuration a detection terminal, the total output of the detection values ​​of the voltage and current detection sensors can be obtained from this detection terminal. This series connection eliminates the need to provide a detection terminal for each sensor output of each voltage and current detection sensor, and reduces the number of detection terminals provided inside the impedance matching device.

[0026] In an impedance matching device composed of an LC circuit consisting of a capacitor and an inductor, the return current path for the return current within the impedance matching device is a current path connecting a connection point that is grounded to the load connected to the impedance matching device via ground, and a connection point where the capacitor of the LC circuit is grounded to ground. The direction of the return current flowing through the return current path switches from the load side to the capacitor side or from the capacitor side to the load side depending on the positive or negative polarity of the AC signal of the high-frequency power supply.

[0027] The voltage-current detection device of the present invention includes a plurality of configuration examples for the arrangement of a pair of voltage-current detection sensors. Configuration examples 1 to 6 and 8 arrange the pair of voltage-current detection sensors symmetrically with respect to the output current path, while configuration example 7 arranges the pair of voltage-current detection sensors facing each other on the front and back sides of the substrate.

[0028] (Example of configuration 1) The first configuration example of the arrangement is one in which a pair of voltage-current detection sensors are arranged at equal angles. Multiple sets of voltage-current detection sensors are provided, and each pair of voltage-current detection sensors is arranged at equal angles in a plane perpendicular to the output current path of the impedance matching device's output current.

[0029] (Second example configuration) A second example of the arrangement configuration is one in which a pair of voltage-current detection sensors are arranged parallel to the magnetic field of the return current. The system includes one pair of voltage-current detection sensors, and the direction in which these sensors are arranged is the same as the direction of the magnetic field generated by the return current.

[0030] (Third example configuration) A third configuration example of the arrangement is one in which a pair of voltage-current detection sensors are arranged in any direction with respect to the magnetic field of the return current. The system includes one pair of voltage-current detection sensors, and the arrangement direction of this pair of voltage-current detection sensors is any direction with respect to the direction of the magnetic field generated by the return current.

[0031] (Fourth example configuration) A fourth configuration example of the arrangement is one in which three pairs of voltage-current sensing sensors are arranged. The system has three pairs of voltage-current sensing sensors, and of these three pairs of sensors, the orientation of one pair of sensors is the same as the direction of the magnetic field generated by the return current, while the orientation of the remaining two pairs of sensors is at an equal angle from the first pair of sensors and in opposite directions.

[0032] (Fifth example configuration) A fifth configuration example of the arrangement is one in which three pairs of voltage-current detection sensors are arranged. The system has three pairs of voltage-current detection sensors, and of these three pairs of voltage-current detection sensors, the central pair is positioned in any direction with respect to the direction of the magnetic field generated by the return current, while the remaining two pairs of voltage-current detection sensors on either side are positioned at equal angles from the central pair of voltage-current detection sensors and in opposite directions.

[0033] (Sixth example configuration) A sixth configuration example of the arrangement is one in which each voltage-current detection sensor in a pair of voltage-current detection sensors is arranged symmetrically with respect to the output current path, with each pair of voltage-current detection sensors being positioned at a different distance from the output current path. Multiple pairs of voltage-current detection sensors are provided, and these multiple pairs of voltage-current detection sensors include pairs at which the output current of the impedance matching device is at a different distance from the output current path.

[0034] (Example of the 7th configuration) A seventh configuration example of the arrangement is one in which pairs of voltage-current detection sensors are arranged on both sides of the substrate. Multiple pairs of voltage-current detection sensors are provided, and the same number of pairs of voltage-current detection sensors are arranged facing each other on the front and back sides of the substrate that form the return current path for the return current, and are arranged symmetrically with respect to the output current path.

[0035] (Example of the 8th configuration) The eighth configuration example of the arrangement is one in which multiple pairs of voltage-current detection sensors are arranged symmetrically with respect to the output current path, and the output current path and the return current path are in a plane parallel to each other.

[0036] The power meter of the present invention comprises a voltage-current detection device of the present invention, a phase calculation unit that calculates the phase difference between voltage and current based on the sum of detected values ​​detected from the voltage-current detection sensor, and a power calculation unit that calculates the power value of the output current of the impedance matching device based on the voltage and current of the sum of the detected values ​​and the phase difference obtained by the phase calculation unit.

[0037] The voltage and current values ​​measured by the voltage and current detection device of the present invention have reduced phase errors. Therefore, the phase of the current calculated by the phase calculation unit is less affected by the magnetic field electromagnetically induced by the return current. By using the phase obtained by the phase calculation unit, it is possible to obtain a power value with reduced influence from the return current. [Effects of the Invention]

[0038] As described above, according to the present invention, the phase error between the detected voltage due to the return current and the detected current in the voltage-current detection sensor inside the impedance matching device can be reduced, and the degree of freedom in arranging the voltage-current detection sensor inside the impedance matching device can be increased. Furthermore, according to the present invention, it is possible to reduce errors in the measured power value caused by phase errors in a voltage-current detection device. [Brief explanation of the drawing]

[0039] [Figure 1] This figure illustrates the schematic of a high-frequency system equipped with the voltage-current detection device of the present invention. [Figure 2] This diagram illustrates an example configuration of an LC circuit that makes up an impedance matching device. [Figure 3] This diagram illustrates the return current pattern inside an impedance matching device. [Figure 4] This is a diagram illustrating the configuration of a voltage and current detection device. [Figure 5] This is a diagram illustrating the configuration of a voltage and current detection device. [Figure 6] This figure illustrates the reduction of noise magnetic fields by the voltage-current detection device of the present invention. [Figure 7] This figure illustrates a first configuration example of the voltage and current detection device of the present invention. [Figure 8] This figure illustrates an example of the internal arrangement of the impedance matching device in a first configuration example of the voltage-current detection device of the present invention. [Figure 9] This diagram illustrates an example configuration of a voltage-current detection sensor. [Figure 10] This diagram illustrates the connection configuration of the voltage-current detection sensor of the present invention. [Figure 11] This figure illustrates the second to sixth configuration examples of the voltage-current detection device of the present invention. [Figure 12] This figure illustrates a seventh configuration example of the voltage-current detection device of the present invention. [Figure 13]This figure illustrates an eighth configuration example of the voltage-current detection device of the present invention. [Figure 14] This figure illustrates the measurement magnetic field and noise magnetic field of the eighth configuration example of the voltage-current detection device of the present invention. [Figure 15] This diagram illustrates an example of an LC circuit that constitutes an impedance matching device. [Modes for carrying out the invention]

[0040] (1) Configuration of the high-frequency system Figure 1 is a schematic diagram of a high-frequency system 10 equipped with the voltage-current detection device 3 of the present invention. The high-frequency system 10 supplies high-frequency power generated by the high-frequency power supply 1 to the load 7.

[0041] The high-frequency power from the high-frequency power supply 1 is supplied to the load 7 via the impedance matching device 2. The impedance matching device 2 can be composed of an LC circuit consisting of a capacitor and an inductor, and the element values ​​of the LC circuit are adjusted so that the matched output matches the load impedance.

[0042] A power meter 6 is provided between the impedance matching device 2 and the load 7 to measure the output power supplied to the load 7. The power meter 6 comprises a voltage / current detection device 3, a phase calculation unit 4, and a power calculation unit 5. The voltage / current detection device 3 measures the voltage and current of the output of the impedance matching device 2, and the phase calculation unit 4 calculates the phase value between the voltage and current using the voltage and current values ​​detected by the voltage / current detection device 3. The phase calculation by the phase calculation unit 4 can be performed using calculation methods such as Fourier transform and Hilbert transform. The power calculation unit 5 calculates the power using the voltage value, current value, and phase value.

[0043] Figure 2 shows an example of the configuration of an impedance matching device using an LC circuit. The impedance matching device shown in Figure 2 is an example of an LC circuit configuration, specifically a circuit configuration called an inverted L type. The impedance matching device 2 has two variable elements, which are variable components used for impedance matching: a first variable capacitor C1 and a second variable capacitor C2, connected in parallel and series with the load 7 to the high-frequency power supply 1, respectively. The capacitance of the first variable capacitor C1 and the second variable capacitor C2 is variable by using general variable capacitors.

[0044] The impedance matching device 2 shown in Figure 2 forms four different current paths depending on the capacitor constant and load conditions. Figure 3 shows two of these four patterns in which the return current flows through the capacitor inside the impedance matching device 2.

[0045] The current paths shown in Figures 3(a) and 3(b) include an output current path 11 through which output current flows between the inductor L and the second capacitor C2 and the load 7, and a return current path 12 through which return current flows between the load 7 and the second capacitor C2 via ground.

[0046] In the current path shown in Figure 3(a), output current flows out towards the load 7 through the output current path 11, and return current Ire flows in from the load 7 towards the first capacitor C1 through the return current path 12. On the other hand, in the current path shown in Figure 3(b), output current flows in from the load 7 through the output current path 11, and return current Ire flows out from the first capacitor C1 towards the load 7 through the return current path 12.

[0047] In addition to the inverted L-type configuration described above, the LC circuit constituting the impedance matching device can also use an L-type configuration or a π-type configuration. Figure 15 shows an example of an LC circuit constituting an impedance matching device.

[0048] Figures 15(a) and 15(b) show examples of inverted L-shaped configurations, Figures 15(c) and 15(d) show examples of L-shaped configurations, and Figures 15(e) and 15(f) show examples of π-shaped configurations.

[0049] (2) Configuration of the voltage and current detection device Figures 4 and 5 are diagrams illustrating the configuration of the voltage-current detection device. In Figure 4, the voltage-current detection device 3 is connected between the output terminal of the impedance matching device 2 and the input terminal of the load 7. The voltage-current detection device 3 includes a voltage-current detection sensor 41 consisting of a voltage detection sensor 42 and a current detection sensor 43.

[0050] In Figure 5, the voltage detection sensor 42 is, as an example, composed of a series-connected space capacitance 42a and a capacitor 42b. Voltage is accumulated in the capacitor 42b via the space capacitance 42a between it and the output current path 11, and a voltage equivalent to the capacitor's voltage divider capacitance is detected from the endpoint of the capacitor 42b.

[0051] The current detection sensor 43 is configured, for example, as a parallel circuit of a secondary coil 43a and a shunt resistor 43b. The output current flowing through the output current path 11 is taken as the current to be measured, and the magnetic field generated by this current induces a secondary current in the secondary coil 43a through electromagnetic induction, which is then detected. The shunt resistor 43b converts the current value of the secondary current into a voltage value and outputs it. The secondary coil 43a can be configured, for example, as an air-core coil.

[0052] (3) Measured magnetic field, noise magnetic field Next, the reduction of the influence of noise magnetic fields in magnetic field detection using the voltage-current detection device 3 of the present invention will be explained with reference to Figure 6. Figure 6(a) shows the measured magnetic field due to the measured current and the noise magnetic field due to the return current, Figure 6(b) shows the measured magnetic field due to the measured current, Figure 6(c) shows the noise magnetic field due to the return current, and Figures 6(d) and 6(e) show the combined magnetic field of the measured magnetic field and the noise magnetic field.

[0053] In Figure 6(b), when the output current Iout flows in the z-axis direction, a ring-shaped measurement magnetic field 31 is formed in the xy-plane perpendicular to the output current path 11. The arrows in Figure 6(b) indicate the direction of the measurement magnetic field 31.

[0054] In Figure 6(c), when a return current Ire flows in the y-axis direction, a noise magnetic field 32 is formed in the xz plane perpendicular to the return current path 12. The arrows in Figure 6(c) indicate the direction of the noise magnetic field 32.

[0055] Figure 6(d) shows the combined magnetic field of the measured magnetic field and the noise magnetic field. When the output current Iout and the return current Ire are orthogonal to each other, the plane on which the measured magnetic field 31 is formed and the plane on which the noise magnetic field 32 is formed are orthogonal to each other. When the return current Ire flows along the y-axis, at two points that are symmetrical to each other on the y-axis with respect to the origin, the magnetic field directions of the measured magnetic field due to the output current Iout are opposite to each other, while the magnetic field directions of the noise magnetic field due to the return current Ire are the same. Therefore, the magnetic field component of the noise magnetic field is added to the measured magnetic field at one point, and the magnetic field component of the noise magnetic field is reduced at the other point.

[0056] Since the return current path 12 is a current path that flows two-dimensionally through the substrate which is grounded, the magnetic field pattern of the noise magnetic field 32 can be considered to be a magnetic field in almost the same direction on a plane parallel to the substrate. The magnetic field shown in Figure 6(e) shows the composite magnetic field when the noise magnetic field 32 can be considered to be a magnetic field in the same direction.

[0057] Since the magnetic field directions of the noise magnetic field 32 can be considered to be approximately the same direction, the magnetic field direction of the noise magnetic field 32 is approximately the same direction at any position in the measured magnetic field 31. For example, when the return current Ire flows along the y-axis, the magnetic field direction of the noise magnetic field 32 is along the x-axis in the xy-plane. On the other hand, the magnetic field direction of the measured magnetic field 31 formed by the output current Iout flowing along the z-axis is in the opposite direction at positions symmetrical to each other with respect to the origin in the xy-plane.

[0058] As a result, the combined magnetic field of any two points symmetrically positioned with respect to the origin will have the following effects: at one point, the magnetic field strength will increase as the noise magnetic field component is added to the measured magnetic field; and at the other point, the magnetic field strength will decrease as the noise magnetic field component is reduced relative to the measured magnetic field.

[0059] At two points in symmetrical positions, the contribution of the noise magnetic field to the measured magnetic field changes depending on the angular position in the xy-plane. In the magnetic field relationship shown in Figure 6(e), it is largest at two points on the y-axis and smallest at two points on the x-axis. On both sides of the x-axis, the polarity of the noise magnetic field contribution is opposite.

[0060] In Figure 6(a), the output current Iout flowing through the output current path 11 inside the impedance matching device 2 forms an annular measurement magnetic field 31 on a plane perpendicular to the output current path 11, while on the same plane, the return current Ire flowing through the return current path 12 forms a noise magnetic field 32.

[0061] A pair of voltage-current detection sensors 41 are positioned symmetrically with respect to the output current path 11 to measure the magnetic field 31. Figure 6(a) shows a configuration in which a pair of voltage-current detection sensors 41Aa and 41Ab are positioned symmetrically in the x-axis direction, and a pair of voltage-current detection sensors 41Ba and 41Bb are positioned symmetrically in the y-axis direction.

[0062] At the position of the voltage-current detection sensor 41Ba, the magnetic field directions of the measurement magnetic field 31 and the noise magnetic field 32 are opposite, and their magnetic field strengths cancel each other out, so the magnetic field strength of the combined magnetic field weakens. On the other hand, at the position of the voltage-current detection sensor 41Bb, the magnetic field directions of the measurement magnetic field 31 and the noise magnetic field 32 are the same, and their magnetic field strengths strengthen each other, so the magnetic field strength of the combined magnetic field strengthens.

[0063] At the position of the voltage / current detection sensor 41Aa, the magnetic field directions of the measurement magnetic field 31 and the noise magnetic field 32 are orthogonal, so the direction of the combined magnetic field is the direction of the vector sum of both magnetic fields. Similarly, at the position of the voltage / current detection sensor 41Ab, the magnetic field directions of the measurement magnetic field 31 and the noise magnetic field 32 are orthogonal, so the direction of the combined magnetic field is the direction of the vector sum of both magnetic fields. Voltage / current detection sensors 41Aa, 41Ab, 41Ba, and 41Bb detect voltage and current from this combined magnetic field.

[0064] The voltage value obtained by the pair of voltage-current detection sensors 41 detecting the combined magnetic field is the sum of the voltage value due to the measured magnetic field 31 and the voltage value due to the noise magnetic field 32. On the other hand, the current value obtained by detecting the combined magnetic field has a phase shift relative to the voltage. If a phase shift occurs in the return current Ire relative to the voltage of the output current path 11 due to the load characteristics, this phase shift will cause a difference in the current value obtained by detecting the combined magnetic field.

[0065] The current value obtained by the voltage-current detection sensors 41Ba and 41Bb detecting the combined magnetic field is the sum of the current value due to the measured magnetic field 31 and the current value due to the noise magnetic field 32. However, the return current Ire has a phase shift, and the direction of this phase shift is opposite to that of phase lead and phase lag. Therefore, the phase shift of the current value detected by the voltage-current detection sensor 41Ba and the phase shift of the current value detected by the voltage-current detection sensor 41Bb are in opposite directions.

[0066] Similarly, the phase difference between the current value detected by the voltage-current detection sensor 41Aa and the phase difference between the current value detected by the voltage-current detection sensor 41Ab are in opposite directions.

[0067] The voltage-current detection device cancels out and reduces the phase error included in the current value detected by the voltage-current detection sensors by summing the detection values ​​of a pair of voltage-current detection sensors located symmetrically to each other.

[0068] (4) Example of voltage and current detection device configuration and measurement example The following describes examples of the configuration and measurement of the voltage-current detection device using Figures 7 to 14. Note that the first to sixth and eighth configurations are examples in which the pair of voltage-current detection sensors are arranged symmetrically with respect to the output current path, while the seventh configuration is an example in which the pair of voltage-current detection sensors are arranged symmetrically in the direction of the output current path.

[0069] (4-1) First Configuration Example A first configuration example and measurement example of the voltage-current detection device will be explained using Figures 7 to 9. The first configuration example shown in Figure 7 is a configuration in which multiple pairs of voltage-current detection sensors 41 are arranged in an annular shape around the output current path 11. A pair of voltage-current detection sensors 41 consists of a total of eight sensors: a pair consisting of two voltage-current detection sensors 41Aa and 41Ab, a pair consisting of two voltage-current detection sensors 41Ba and 41Bb, a pair consisting of two voltage-current detection sensors 41Ca and 41Cb, and a pair consisting of two voltage-current detection sensors 41Da and 41Db. These eight voltage-current detection sensors 41 are arranged around the output current path 11. Each pair of voltage-current detection sensors 41 is positioned symmetrically with respect to the output current path 11. The first configuration example shown in Figure 7 illustrates an example in which eight voltage-current detection sensors 41 are arranged at equal intervals on a circle centered on the output current path 11.

[0070] Figure 7(a) shows the case where the output current Iout flows through the output current path 11 from the front to the back of the drawing. The direction of the magnetic field of the measurement magnetic field 31 formed by the output current Iout is clockwise around the output current path 11, and the direction of the magnetic field of the noise magnetic field 32 formed by the return current Ire flowing in the direction of the arrow is from the lower right to the upper left of the drawing.

[0071] Figure 7(b) shows the case where the output current Iout flows through the output current path 11 from the back to the front of the drawing. The direction of the magnetic field of the measurement magnetic field 31 formed by the output current Iout is counterclockwise around the output current path 11, and the direction of the magnetic field of the noise magnetic field 32 formed by the return current Ire flowing in the direction of the arrow is from the upper left to the lower right of the drawing.

[0072] Figure 8 shows an example in which the voltage-current detection device shown in Figure 7(a) is arranged inside the impedance matching device 2. Figure 8(a) is a top view, Figure 8(b) is a front view from the side, and Figure 8(c) shows a measurement example.

[0073] In Figures 8(a) and 8(b), the first capacitor C1, the second capacitor C2, and the inductor L, which constitute the impedance matching device 2, are arranged on the substrate 50. An output current Iout is output from the second capacitor C2 via the output current path 11 toward the output port connected to the load side (not shown). The load side of the substrate 50 is grounded via ground. The return current Ire from the load flows through the return current path 12 between the grounding point with the load side and the first capacitor C1. The output current Iout forms a ring-shaped measurement magnetic field 31 centered on the output current path 11, and the return current Ire forms a noise magnetic field 32 centered on the return current path 12. The direction of the noise magnetic field 32 is opposite on the inside and outside of the impedance matching device 2 with the substrate 50 in between, and the direction of the noise magnetic field inside the impedance matching device 2 can be considered as a unidirectional magnetic field moving from the lower right to the upper left on the drawing, as shown in Figure 8(c).

[0074] The voltage-current detection sensors 41 of the voltage-current detection device 3 are arranged around the output current path 11 inside the impedance matching device 2 and detect the combined magnetic field obtained by combining the measurement magnetic field 31 and the noise magnetic field 32. In Figure 8(c), the pairs of voltage-current detection sensors 41Aa and 41Ab, 41Ba and 41Bb, 41Ca and 41Cb, and 41Da and 41Db are each arranged symmetrically across the output current path 11. Figure 8(c) shows an example in which each voltage-current detection sensor 41 is arranged at equal angular intervals of 45°.

[0075] When load 7 is a capacitive load, the return current Ire flowing through the return current path 12 from load 7 to the first capacitor C1 of impedance matching device 2 becomes capacitive and leads the voltage in phase.

[0076] If the return current Ire has a phase lead or phase lag, the noise magnetic field will be affected by the phase. Since the combined magnetic field is a combination of the measured magnetic field and the noise magnetic field, the combined magnetic field will also be affected by the phase of the return current Ire.

[0077] The direction in which the measurement magnetic field 31 is affected by the noise magnetic field 32 is opposite to the direction of the noise magnetic field, across the straight line passing through the output current path 11. In Figure 8(c), in the range to the right of the straight line AB, the measurement magnetic field 31 is affected by a magnetic field in the opposite direction from the noise magnetic field 32. When the return current Ire is phase-leading, the measurement magnetic field 31 is affected by a direction that lags the phase from the noise magnetic field 32, resulting in a relative phase lag, and the voltage-current detection sensor 41 detects a phase-lag current.

[0078] On the other hand, in the range to the left of the straight line AB, the measurement magnetic field 31 is affected by a magnetic field in the same direction from the noise magnetic field 32. When the return current Ire is phase-leading, the measurement magnetic field 31 is affected by the noise magnetic field 32 in the direction of phase leading, resulting in a relative phase-leading effect, and the voltage-current detection sensor 41 detects a current with a phase-leading effect.

[0079] In a pair of voltage-current sensing sensors, one sensing current is phase-lag and the other sensing current is phase-leaning. Therefore, when the two sensing currents are added together, the phase differences cancel each other out, reducing the phase error.

[0080] In Figure 8(c), the pair of voltage-current detection sensors 41C, consisting of voltage-current detection sensor 41Ca and voltage-current detection sensor 41Cb, is greatly affected by the noise magnetic field because the measurement magnetic field and the noise magnetic field are parallel. On the other hand, the pair of voltage-current detection sensors 41A, consisting of voltage-current detection sensors 41Aa and voltage-current detection sensor 41Ab, which are arranged orthogonally to the pair of voltage-current detection sensors 41C, is less affected by the noise magnetic field because the measurement magnetic field and the noise magnetic field are orthogonal to each other.

[0081] Figure 9, similar to Figure 8, shows an example in which the voltage-current detection device configuration shown in Figure 7 is arranged inside the impedance matching device 2. Figure 9(a) is a top view, Figure 9(b) is a front view from the side, and Figure 9(c) shows a measurement example. The configuration in Figure 9 differs from that in Figure 8 in that the current direction of the measurement current and the return current are different, but other than the current direction and magnetic field direction, it is the same as in Figure 8.

[0082] In Figures 9(a) and (b), the first capacitor C1, the second capacitor C2, and the inductor L constituting the impedance matching device 2 are arranged on a substrate 50, and an output current Iout flows from the output port connected to the load side to the second capacitor C2 via the output current path 11. The substrate 50 is grounded via ground. The return current Ire flowing to the load flows through the return current path 12 between the first capacitor C1 and the ground point on the load side. The output current Iout forms a ring-shaped measurement magnetic field 31 centered on the output current path 11, and the return current Ire forms a noise magnetic field 32 centered on the return current path 12. The direction of the noise magnetic field 32 is opposite on the inside and outside of the impedance matching device 2 with the substrate 50 in between, and the direction of the noise magnetic field inside the impedance matching device 2 can be considered as a unidirectional magnetic field from the upper left to the lower right on the drawing, as shown in Figure 9(c).

[0083] As an example, the voltage-current detection sensors 41 of the voltage-current detection device 3 are arranged around the output current path 11 inside the impedance matching device 2 and detect the combined magnetic field obtained by combining the measurement magnetic field 31 and the noise magnetic field 32. In Figure 9(c), the pairs of voltage-current detection sensors 41Aa and 41Ab, 41Ba and 41Bb, 41Ca and 41Cb, and 41Da and 41Db are each arranged symmetrically across the output current path 11. Figure 9(c) shows an example in which each voltage-current detection sensor 41 is arranged at equal angular intervals of 45°.

[0084] When load 7 is a capacitive load, the return current Ire flowing through the return current path 12 from the first capacitor C1 of the impedance matching device 2 toward load 7 becomes capacitive and leads the voltage in phase.

[0085] If the return current Ire has a phase lead or phase lag, the noise magnetic field will be affected by the phase. Since the combined magnetic field is a combination of the measured magnetic field and the noise magnetic field, the combined magnetic field will also be affected by the phase of the return current Ire.

[0086] The direction in which the measurement magnetic field 31 is affected by the noise magnetic field 32 is opposite to the direction of the noise magnetic field, across the straight line passing through the output current path 11. In Figure 9(c), in the range to the right of the straight line AB, the measurement magnetic field 31 is affected by a magnetic field in the opposite direction from the noise magnetic field 32. When the return current Ire is phase-leading, the measurement magnetic field 31 is affected by a direction that lags the phase from the noise magnetic field 32, resulting in a relative phase lag, and the voltage-current detection sensor 41 detects a phase-lag current.

[0087] On the other hand, in the range to the left of the straight line AB, the measurement magnetic field 31 is affected by a magnetic field in the same direction from the noise magnetic field 32. When the return current Ire is phase-leading, the measurement magnetic field 31 is affected by the noise magnetic field 32 in the direction of phase leading, resulting in a relative phase-leading effect, and the voltage-current detection sensor 41 detects a current with a phase-leading effect.

[0088] In a pair of voltage-current sensing sensors, one sensing current is phase-lag and the other sensing current is phase-leaning. Therefore, when the two sensing currents are added together, the phase differences cancel each other out, reducing the phase error.

[0089] In Figure 9(c), the pair of voltage-current detection sensors 41C, consisting of voltage-current detection sensor 41Ca and voltage-current detection sensor 41Cb, has parallel measurement magnetic fields, so the measurement magnetic field is greatly affected by the noise magnetic field. On the other hand, the pair of voltage-current detection sensors 41A, consisting of voltage-current detection sensors 41Aa and voltage-current detection sensor 41Ab, which are arranged orthogonally to the pair of voltage-current detection sensors 41C, has orthogonal measurement magnetic fields, so the measurement magnetic field is less affected by the noise magnetic field.

[0090] (4-2) Series connection of voltage and current detection sensors Figure 10 is a diagram illustrating the connection configuration of voltage-current detection sensors. By connecting multiple voltage-current detection sensors 41 that constitute the voltage-current detection device in series, the detection value is obtained by summing the detection outputs of each voltage-current detection sensor 41. In Figure 10(a), adjacent voltage-current detection sensors 41 are connected in series, and the connection point between adjacent voltage-current detection sensors 41 is designated as the measurement point 61. The measurement point at the end of the series-connected voltage-current detection sensors 41 is designated as the detection end 62, and the detection value obtained by summing the detection outputs of each voltage-current detection sensor 41 is output.

[0091] Figure 10(b) shows an example of the connection of the voltage detection sensor 42. When the voltage detection sensor 42 is composed of voltage dividers, the voltage divider ends of adjacent voltage dividers are designated as measurement points 61a, and these are connected sequentially, with one end of the measurement point 61a designated as the voltage detection end 62a. The total voltage, which is the sum of the detected voltages of each voltage detection sensor 42, is detected from the voltage detection end 62a.

[0092] Figure 10(c) shows an example of the connection of the current detection sensor 43. When the current detection sensor 43 is composed of a secondary coil and a shunt resistor connected in parallel, the ends of adjacent shunt resistors are designated as measurement points 61b, and these are connected sequentially, with one end of the measurement point 61b designated as the current detection terminal 62b. The total current, which is the sum of the detected currents of each current detection sensor 43, is detected from the current detection terminal 62b.

[0093] By connecting voltage and current sensors in series, the need for a feedback port, which is required in a configuration where each voltage and current sensor measures a value, can be eliminated. Furthermore, by using the connection points between each voltage and current sensor as measurement points, the detected values ​​of each voltage and current sensor can be obtained from each connection point, and the voltage, current, and magnetic field strength at the points where each voltage and current sensor is located can be determined.

[0094] (4-3) Example 2 to Example 8 The second to eighth configuration examples of the voltage-current detection device of the present invention will be explained with reference to Figures 11 to 14.

[0095] (a) Second configuration example Figure 11(a) shows a second configuration example. In the second configuration example, only one pair of voltage-current detection sensors 41A, consisting of voltage-current detection sensors 41Aa and 41Ab, is arranged along the line AB in the direction of the noise magnetic field. In the figure, the arrow pointing from the lower right to the upper left indicates the direction of the noise magnetic field. At positions symmetrical to the noise magnetic field with respect to the output current path 11, the noise magnetic field 32 is orthogonal to the measurement magnetic field 31, so the influence of the noise magnetic field 32 on the measurement magnetic field 31 is small, and at symmetrical positions, the direction in which the noise magnetic field 32 influences the measurement magnetic field 31 is opposite. As a result, of the detection currents detected by the pair of voltage-current detection sensors 41Aa and 41Ab, the detection current portion due to the noise magnetic field 32 is in opposite phase, and the influence of the noise magnetic field 32 cancels out in the total detection current. On the other hand, the detection current portion due to the measurement magnetic field 31 is added together. As for the detection voltage, it is not affected by the phase shift caused by the noise magnetic field 32, so the sum of the detection voltages of the two voltage sensors is obtained by summing them together.

[0096] Therefore, when the direction of the noise magnetic field is known, the arrangement of the second configuration example makes it possible to detect the detected voltage and current with sufficient accuracy. Furthermore, it is possible to reduce the number of voltage and current detection sensors and to increase the degree of freedom in arranging the voltage and current detection sensors inside the impedance matching device.

[0097] (b) Third configuration example Figure 11(b) shows a third configuration example. Similar to the second configuration example, the third configuration example uses only one pair of voltage-current detection sensors 41A, and the pair of voltage-current detection sensors 41Aa and 41Ab are placed at an angular position shifted by an arbitrary angle θ with respect to the line AB in the direction of the noise magnetic field.

[0098] Since the voltage-current detection sensors 41Aa and 41Ab are positioned symmetrically with respect to the output current path 11, the influence of the noise magnetic field on the measurement magnetic field is greater in this position compared to the position in the second configuration example, but the degree of influence is the same and in opposite directions. Therefore, in the detection values ​​detected by the voltage-current detection sensors 41Aa and 41Ab, the phase of the detection current due to the noise magnetic field is in opposite directions, and they cancel each other out when the detection currents are added together. As for the detection voltage, it is not affected by the phase shift caused by the noise magnetic field 32, so by adding them together, a value obtained is obtained by adding the detection voltages of the two voltage sensors.

[0099] Therefore, if the direction of the noise magnetic field is known, the arrangement of the third configuration example makes it possible to detect the detected voltage and current with sufficient accuracy. Furthermore, the number of voltage and current detection sensors can be reduced, and the installation angle can be set arbitrarily, thus increasing the flexibility in arranging the voltage and current detection sensors inside the impedance matching device.

[0100] (c) Fourth configuration example Figure 11(c) shows a fourth configuration example. In the fourth configuration example, three pairs of voltage-current detection sensors 41A, 41B, and 41C are arranged along the direction of the noise magnetic field. Of the three pairs of voltage-current detection sensors, one pair of sensors 41Aa, 41Ab is positioned on line AB in the direction of the noise magnetic field passing through the output current path 11, while the remaining two pairs of sensors 41Ba, 41Bb and the pair of sensors 41Ca, 41Cb are positioned at angles shifted by a predetermined angle Δθ in opposite directions from the angular position where the sensors 41Aa, 41Ab are positioned. The centrally positioned sensors 41Aa, 41Ab detect the composite magnetic field with the least influence from the noise magnetic field, while the sensors 41Ba, 41Bb and 41Ca, 41Cb, positioned on either side, are affected by the noise magnetic field in opposite directions.

[0101] By shifting the installation angles of the voltage-current detection sensors 41A, 41B, and 41C, which detect the combined magnetic field, by a predetermined angle Δθ so that they are adjacent to each other, the voltage-current detection sensors 41B and 41C will detect almost the same combined magnetic field as the voltage-current detection sensor 41A, although they will differ from the voltage-current detection sensor 41A by the amount of the angle difference in placement.

[0102] In the fourth configuration example, similar to the third configuration example, the measurement magnetic field 31 and the noise magnetic field 32 are orthogonal to each other at positions symmetrical with respect to the output current path 11 on the line AB in the direction of the noise magnetic field passing through the output current path 11. Therefore, the influence of the noise magnetic field 32 on the measurement magnetic field 31 is small, and the direction in which the noise magnetic field 32 influences the measurement magnetic field 31 is opposite. As a result, the directions of the phase shift of the detected current due to the noise magnetic field are opposite, with phase leading and phase lagging, and they cancel each other out in the combined detected current.

[0103] Therefore, when the direction of the noise magnetic field is known, the detected voltage and current can be detected with sufficient accuracy by using the fourth configuration example, and the detection output is increased by using three sets of voltage-current detection sensors 41.

[0104] (d) Fifth configuration example Figure 11(d) shows the fifth configuration example. Similar to the fourth configuration example, the fifth configuration example includes three pairs of voltage-current detection sensors 41A, 41B, and 41C. In the fourth configuration example, the three pairs of voltage-current detection sensors 41A, 41B, and 41C are arranged along the line AB in the direction of the noise magnetic field, whereas in the fifth configuration example, the three pairs of voltage-current detection sensors 41A, 41B, and 41C are arranged with their positions shifted by arbitrary angles θ, θ+Δθ, and θ-Δθ from the line AB in the direction of the magnetic field, with the output current path 11 as the center.

[0105] Since the voltage-current detection sensors 41Aa and 41Ab, voltage-current detection sensors 41Ba and 41Bb, and voltage-current detection sensors 41Ca and 41Cb are each positioned symmetrically with respect to the output current path 11, the influence of the magnetic field on the measurement magnetic field from the noise magnetic field is greater compared to the arrangement in the fourth configuration example, but the degree of influence is the same and in opposite directions. Therefore, for example, in the detection values ​​detected by voltage-current detection sensor 41Aa and voltage-current detection sensor 41Ab, the phase of the detection current due to the noise magnetic field is in opposite directions, and they cancel each other out when the detection currents are added together. Similarly, for voltage-current detection sensors 41Ba and 41Bb, and voltage-current detection sensor 41Ca and voltage-current detection sensor 41Cb, although the magnitude of the detection current affected by the noise magnetic field is different, the phase of the detection current due to the noise magnetic field is in opposite directions, and they cancel each other out when the detection currents are added together.

[0106] Since the detected voltage is not affected by the phase shift caused by the noise magnetic field 32, summing them up yields the sum of the detected voltages of the two voltage sensors.

[0107] Therefore, if the direction of the noise magnetic field is known, the arrangement of the fifth configuration example makes it possible to detect the detected voltage and current with sufficient accuracy. Furthermore, the number of voltage and current detection sensors can be reduced, and the installation angle can be set arbitrarily, thus increasing the flexibility in arranging the voltage and current detection sensors inside the impedance matching device.

[0108] (e) Sixth configuration example Figure 11(e) shows a sixth configuration example. The sixth configuration example includes two pairs of voltage-current detection sensors, each consisting of a pair of voltage-current detection sensors 41Aa, 41Ab and a pair of voltage-current detection sensors 41Ab, 41Bb.

[0109] One pair of voltage-current detection sensors 41Aa and 41Ab are arranged along the line AB in the direction of the noise magnetic field, similar to the second configuration example. In contrast, the other pair of voltage-current detection sensors 41Ba and 41Bb are arranged in a direction perpendicular to the line AB in the direction of the noise magnetic field, and their distance from the output current path 11 is different from the distance of the pair of voltage-current detection sensors 41Aa and 41Ab. In the example shown in Figure 11(e), the distance of the voltage-current detection sensors 41Ba and 41Bb from the output current path 11 is shorter than the distance of the voltage-current detection sensors 41Aa and 41Ab. Note that the distance of the voltage-current detection sensors 41Ba and 41Bb may be longer than the distance of the voltage-current detection sensors 41Aa and 41Ab.

[0110] The voltage and current values ​​detected by the voltage and current detection sensors 41Ba and 41Bb are greater than the voltage and current values ​​detected by the voltage and current detection sensors 41Aa and 41Ab. However, the effect of canceling out the phase lead and phase lag of the total current value is the same as in the second configuration example.

[0111] According to the sixth configuration example, the distance from the output current path 11 to the pair of voltage-current detection sensors can be arbitrarily set for each pair of voltage-current detection sensors, provided that the distances from each sensor are the same.

[0112] Furthermore, in the example configuration shown in Figure 11(e), the angular distance between the two voltage-current detection sensor pairs is set to 90°, but any angular distance may be used. The number of voltage-current detection sensor pairs to be placed may also be any number.

[0113] (f) Seventh configuration example The seventh configuration example involves arranging multiple pairs of voltage-current detection sensors on the front and back of a substrate that forms the return current path for the return current, with the same number of pairs facing each other and arranged symmetrically with respect to the output current path.

[0114] Figure 12(a) shows a top view, Figure 12(b) shows a front view from the side, and Figures 12(c) and 12(d) show measurement examples.

[0115] In Figures 12(a) and (b), the first capacitor C1, the second capacitor C2, and the inductor L, which constitute the impedance matching device 2, are arranged on a substrate 50. An output current Iout is output from the second capacitor C2 to an output port connected to the load side (not shown) via an output current path 11. The substrate 50 is connected to the load side via ground. The return current Ire from the load flows through the return current path 12 between the ground point with the load side and the first capacitor C1. The output current Iout forms a ring-shaped measurement magnetic field 31 centered on the output current path 11, and the return current Ire forms a noise magnetic field 32 centered on the return current path 12. The magnetic field direction of the noise magnetic field 32 is opposite on the inside and outside of the impedance matching device 2, with the substrate 50 in between. The noise magnetic field direction inside the impedance matching device 2 can be considered as a unidirectional magnetic field moving from the lower right to the upper left on the drawing, as shown in Figure 12(c), and the noise magnetic field direction outside the impedance matching device 2 can be considered as a unidirectional magnetic field moving from the upper left to the lower right on the drawing, as shown in Figure 12(d).

[0116] The voltage and current detection sensors of the voltage and current detection device 3 are arranged around the output current path 11 on both the inside and outside sides of the impedance matching device 2, and detect the combined magnetic field obtained by combining the measurement magnetic field 31 and the noise magnetic field 32. In Figures 12(c) and (d), the pairs of voltage and current detection sensors 41Aa and 41Ab, 41Ba and 41Bb, 41Ca and 41Cb, and 41Da and 41Db are each arranged opposite each other with the substrate 50 in between. In the arrangement examples shown in Figures 12(c) and 12(d), the voltage and current detection sensors 41A and 41C are arranged symmetrically with respect to the output current path 11 on the inside and outside sides of the impedance matching device 2, and the voltage and current detection sensors 41B and 41D are arranged symmetrically with respect to the output current path 11.

[0117] If the return current Ire has a phase lead or phase lag, the noise magnetic field will be affected by the phase. Since the combined magnetic field is a combination of the measured magnetic field and the noise magnetic field, the combined magnetic field will also be affected by the phase of the return current Ire.

[0118] The direction in which the measurement magnetic field 31 is affected by the noise magnetic field 32 is opposite to the direction on either side of the substrate 50 on which the return current path 12 is formed. In Figures 12(c) and (d), at the positions where the voltage-current detection sensors 41Aa, 41Ba, 41Ca, and 41Da are located inside the impedance matching device 2 with the substrate 50 in between, and where the voltage-current detection sensors 41Ab, 41Bb, 41Cb, and 41Db are located outside the impedance matching device 2, the measurement magnetic field 31 is affected by a magnetic field in the opposite direction from the noise magnetic field 32.

[0119] When the measurement magnetic field 31 and the noise magnetic field 32 are in the same direction, if the return current Ire is phase-leading, the measurement magnetic field 31 is relatively phase-leading due to the influence of the noise magnetic field 32 in the direction of phase leading. On the other hand, when the measurement magnetic field 31 and the noise magnetic field 32 are in opposite directions, if the return current Ire is phase-leading, the measurement magnetic field 31 is relatively phase-lagging due to the influence of the noise magnetic field 32 in the direction of phase lag.

[0120] The detection currents of voltage-current detection sensors 41Aa and 41Ab are such that one detection current is phase-lagging and the other detection current is phase-leading. Therefore, when the detection currents of both sensors are added together, the phase difference cancels out, and the phase error is reduced.

[0121] Similarly, for the detection currents of voltage-current detection sensors 41Ba and 41Bb, voltage-current detection sensors 41Ca and 41Cb, and voltage-current detection sensors 41Da and 41Db, ​​the phase difference between the two detection currents is canceled out when the total detection current is added, reducing the phase error.

[0122] In Figures 12(c) and (d), the pair of voltage-current detection sensors 41A, consisting of voltage-current detection sensor 41Ca and voltage-current detection sensor 41Ab, and the pair of voltage-current detection sensors 41C, consisting of voltage-current detection sensor 41Ca and voltage-current detection sensor 41Cb, have the measurement magnetic field and the noise magnetic field orthogonal, so the measurement magnetic field is less affected by the noise magnetic field. On the other hand, the pair of voltage-current detection sensors 41B, consisting of voltage-current detection sensor 41Ba and voltage-current detection sensor 41Bb, and the pair of voltage-current detection sensors 41D, consisting of voltage-current detection sensor 41Da and voltage-current detection sensor 41Db, ​​have the measurement magnetic field and the noise magnetic field parallel, so the measurement magnetic field is more affected by the noise magnetic field.

[0123] (g) 8th configuration example The eighth configuration example is one in which the output current path 11 and the return current path 12 are in a plane parallel to each other, and multiple pairs of voltage-current detection sensors are arranged symmetrically with respect to the output current path 11, similar to the first to sixth configuration examples.

[0124] Figure 13(a) shows a top view, Figure 13(b) shows a front view from the side, Figure 13(c) shows a measurement example, and Figure 14 shows the measured magnetic field and noise magnetic field.

[0125] In Figures 13(a) and (b), the first capacitor C1, the second capacitor C2, and the inductor L, which constitute the impedance matching device 2, are arranged on a substrate 50. An output current Iout is output from the second capacitor C2 to an output port connected to the load side (not shown) via an output current path 11. The substrate 50 is connected to the load side via ground. The return current Ire from the load flows through the return current path 12 between the ground point with the load side and the first capacitor C1. At this time, the surface on which the output current path 11 is formed and the surface on the substrate 50 on which the return current path 12 is formed are approximately parallel.

[0126] The output current Iout forms a ring-shaped measurement magnetic field 31 centered on the output current path 11, and the return current Ire forms a noise magnetic field 32 centered on the return current path 12. The direction of the noise magnetic field 32 is opposite on the inside and outside of the impedance matching device 2, with the substrate 50 in between. The noise magnetic field direction inside the impedance matching device 2 can be considered as a unidirectional magnetic field, as shown in Figure 13(c). Note that Figure 13(c) shows the view from the output end side to the right of Figure 13(b).

[0127] The voltage-current detection sensor 41 of the voltage-current detection device 3 is positioned inside the impedance matching device 2 around the output current path 11 and detects the combined magnetic field obtained by combining the measurement magnetic field 31 and the noise magnetic field 32.

[0128] In Figure 14(a), of the pair of voltage-current detection sensors 41 arranged symmetrically with respect to the output current path 11, the magnetic field directions of the measured magnetic field and the noise magnetic field are opposite at the position of one voltage-current detection sensor 41Aa, while the magnetic field directions of the measured magnetic field and the noise magnetic field are the same at the position of the other voltage-current detection sensor 41Ab.

[0129] If the return current Ire has a phase lead or phase lag, the noise magnetic field will be affected by the phase. Since the combined magnetic field is a combination of the measured magnetic field and the noise magnetic field, the combined magnetic field will also be affected by the phase of the return current Ire.

[0130] Figure 14(b) shows the measured magnetic field generated by the output current Iout flowing through the output current path 11, and Figure 14(c) shows the noise magnetic field generated by the return current Ire flowing through the return current path 12. Figures 14(b) and 14(c) show the state in which both the output current path 11 and the return current path 12 are arranged in the x-axis direction, with the output current Iout flowing in the positive x-axis direction and the return current Ire flowing in the negative x-axis direction. The measured magnetic field due to the output current Iout and the noise magnetic field due to the return current Ire are formed in the yz plane. In the positive z-axis direction, the magnetic field direction of the measured magnetic field and the magnetic field direction of the noise magnetic field are opposite. The positive z-axis direction corresponds to the inside of the impedance matching device with the substrate 50 in between in Figure 13(b).

[0131] Figure 14(d) shows the combined magnetic field of the measured magnetic field in Figure 14(b) and the noise magnetic field in Figure 14(c). The magnetic field directions of the measured magnetic field and the noise magnetic field are opposite, and the magnetic field direction of the noise magnetic field is the same as that of the measured magnetic field. Therefore, the magnetic field direction of the noise magnetic field is opposite to that of the measured magnetic field in the positive z-axis direction, and the magnetic field direction of the noise magnetic field is the same as that of the measured magnetic field in the negative z-axis direction.

[0132] Therefore, in Figure 14(a), at the positions where the voltage-current detection sensors 41Aa and 41Ab are located inside the impedance matching device 2 and are positioned in opposite directions in the z-axis direction relative to the output current path 11, the measurement magnetic field 31 is affected by a magnetic field in the opposite direction from the noise magnetic field 32.

[0133] When the measurement magnetic field 31 and the noise magnetic field 32 are in the same direction, if the return current Ire is phase-leading, the measurement magnetic field 31 is relatively phase-leading due to the influence of the noise magnetic field 32 in the direction of phase leading. When the measurement magnetic field 31 and the noise magnetic field 32 are in opposite directions, if the return current Ire is phase-leading, the measurement magnetic field 31 is relatively phase-lagging due to the influence of the noise magnetic field 32 in the direction of phase lag.

[0134] The detection currents of voltage-current detection sensors 41Aa and 41Ab are phase-lagging and phase-leading, respectively. Therefore, the phase difference between the two detection currents is canceled out when the two detection currents are added together, reducing the phase error. [Industrial applicability]

[0135] The voltage and current detection device and power meter of the present invention can be applied to semiconductor manufacturing equipment. [Explanation of Symbols]

[0136] 1 High frequency power supply 2. Impedance matching device 3. Voltage and Current Detection Device 4 Phase calculation section 5 Power calculation section 6 Power meter 7 Load 10 High-Frequency Systems 11 Output current path 12. Return current path 31. Measuring magnetic field 32 Noise Magnetic Field 41 Voltage and Current Detection Sensor 41A, 41B, 41C, 41D Voltage and Current Detection Sensors 41Aa, 41Ab, 41Ba, 41Bb, 41Ca, 41Cb, 41Da, 41Db Voltage and Current Detection Sensor 42 Voltage detection sensor 42a space capacity 42b Capacitor 43 Current detection sensor 43a Secondary coil 43b Shunt resistor 50 circuit boards 61a Measurement point 61b Measurement point 62 Detection terminal 62a Voltage detection terminal 62b Current detection terminal C1 First variable capacitor C2 is the second variable capacitor. Iout output current Ire return current

Claims

1. A voltage and current detection device for detecting the output voltage and current of an impedance matching device installed between a high-frequency power supply and a load, The system includes at least one pair of voltage-current detection sensors, each consisting of a current detection sensor that detects the output current flowing through the output current path of the impedance matching device by electromagnetic induction, and a voltage detection sensor that detects the voltage of the output current path by spatial voltage division. In each pair of voltage-current detection sensors, each pair of voltage-current sensors is: (a) Arranged symmetrically with respect to the output current path, (b) With respect to the noise magnetic field generated by the return current flowing through the return current path of the impedance matching device connected to the load via ground, the detection directions of the magnetic fields of the current detection sensors are arranged in opposite directions to each other. (c) The current detection sensor detects the measurement magnetic field generated by the output current and the noise magnetic field generated by the return current which is orthogonal to the measurement magnetic field. (d) The sensor terminals of the voltage-current detection sensor are connected in series by sequentially connecting the measurement terminals of the current detection sensor and sequentially connecting the measurement terminals of the voltage detection sensor, with one end of the series connection being the detection terminal. (e) The total current detected by the current detection sensor and the total voltage detected by the voltage detection sensor are output from the detection terminal. Voltage and current detection device.

2. Each pair of voltage-current detection sensors is symmetrical with respect to the output current path. The return current path of the aforementioned return current is a current path connecting the connection point where the load and ground are connected and the ground point of the capacitor of the impedance matching device. The voltage and current detection device according to claim 1.

3. Each pair of voltage-current detection sensors is symmetrical with respect to the output current path. The system comprises multiple sets of the aforementioned pair of voltage-current detection sensors, and each set of voltage-current detection sensors is arranged at equal angles in a plane perpendicular to the output current path of the impedance matching device. The voltage and current detection device according to claim 1.

4. Each pair of voltage-current detection sensors is symmetrical with respect to the output current path. The system comprises one pair of voltage-current detection sensors, and the arrangement of these pair of voltage-current detection sensors is in the same direction as the magnetic field direction of the noise magnetic field generated by the return current. The voltage and current detection device according to claim 1.

5. The system comprises three sets of the aforementioned pair of voltage-current detection sensors, and each of the three sets of the aforementioned pair of voltage-current detection sensors is symmetrical with respect to the output current path. The orientation of a pair of voltage-current detection sensors is the same as the direction of the magnetic field generated by the return current. The remaining two pairs of voltage-current detection sensors are arranged in an equi-angle configuration, facing opposite directions from the aforementioned pair of voltage-current detection sensors. The voltage and current detection device according to claim 1.

6. The system comprises three sets of the aforementioned pair of voltage-current detection sensors, and each of the three sets of the aforementioned pair of voltage-current detection sensors is symmetrical with respect to the output current path. The orientation of the central pair of voltage-current detection sensors is arbitrary with respect to the direction of the magnetic field generated by the return current. The remaining two pairs of voltage-current detection sensors on both sides are arranged at equal angles from the central pair of voltage-current detection sensors, in opposite directions. The voltage and current detection device according to claim 1.

7. Multiple sets of the aforementioned pair of voltage-current detection sensors are provided, Each pair of voltage-current detection sensors is symmetrical with respect to the output current path. The aforementioned set of voltage-current detection sensors is arranged in a configuration in which sets of sensors are provided with different distances from the output current path of the impedance matching device. The voltage and current detection device according to claim 1.

8. Multiple sets of the aforementioned pair of voltage-current detection sensors are provided, The output current path is connected to the load outside the impedance matching device, with the substrate in between. The substrate is connected to the inside of the impedance matching device via ground to form the return current path. The voltage and current detection sensors of the aforementioned multiple pairs of voltage and current detection sensors are arranged so that they are opposite each other with respect to the substrate, symmetrical with respect to the output current path, and the same number of pairs are arranged. The voltage and current detection device according to claim 1.

9. The output current path and the return current path of the return current are located in planes parallel to each other. The voltage and current detection device according to claim 1.

10. A voltage-current detection device according to any one of claims 1 to 9, A phase calculation unit calculates the phase difference between voltage and current based on the sum of the detected values ​​detected from the voltage and current detection sensor, A power calculation unit calculates the power value of the output current of the impedance matching device based on the total voltage current of the detected values ​​and the phase difference obtained by the phase calculation unit, A power meter equipped with a power meter.

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