Impedance matching circuit and plasma processing apparatus

Abstract

The utility model provides a kind of impedance matching circuit and plasma processing equipment, it is related to electronic circuit technical field, and plasma processing equipment is used to connect load, to improve the surface performance of load. Plasma processing equipment includes radio frequency module, impedance matching circuit is connected between radio frequency module and load in series, and impedance matching circuit includes: inductance adjusting circuit and control circuit. Wherein, the input end of inductance adjusting circuit is connected radio frequency module, and the output end of inductance adjusting circuit is connected load;The control end of control circuit is connected with inductance adjusting circuit. In practical application, control circuit is used to adjust the inductance of inductance adjusting circuit, to make the impedance matching between radio frequency module and load. The utility model adjusts the inductance of inductance adjusting circuit, to adjust the impedance of radio frequency module, so that the impedance matching between radio frequency module and load, keep the energy maximization of radio frequency module, improve the life, flexibility and safety of impedance matching circuit.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to an impedance matching circuit and a plasma processing device. Background Technology

[0002] In plasma processing technology, such as in microelectronic processes like thin film preparation and cleaning, the high-frequency microwave signal emitted by the radio frequency (RF) module in the plasma processing equipment is applied to the reactant gas in the vacuum chamber through a matching network, causing ionization and plasma generation. Variations in process parameters such as chamber pressure and gas flow rate can lead to load impedance fluctuations, causing impedance mismatch and increased reflected power. This can damage internal components of the RF module and potentially cause glow discharge instability, affecting the performance of the processed products. Therefore, when there is impedance mismatch between the RF module and the load, some energy will be reflected, preventing the RF energy from being fully utilized, reducing circuit efficiency, and even shortening circuit lifespan. To address these issues, automatic impedance matching technology is needed to ensure plasma stability and rapid impedance matching, thereby improving processing quality and efficiency. Implementing automatic impedance matching through impedance matching circuits ensures that the high-frequency microwave signal from the plasma processing equipment can be smoothly transmitted to the load point with minimal signal reflection back to the source point, thus improving energy efficiency. When the internal resistance of the signal source is equal in magnitude and phase to the characteristic impedance of the transmission line, or when the characteristic impedance of the transmission line is equal in magnitude and phase to the impedance of the connected load, the input or output terminal of the plasma processing equipment's transmission line can be considered to be in an impedance-matched state. This state is crucial for reducing signal loss and improving signal quality.

[0003] However, when using impedance matching circuits to achieve automatic impedance matching, the load impedance is usually assumed to be fixed. The impedance of the impedance matching circuit is adjusted based on this fixed load impedance, resulting in a fixed impedance for the circuit itself. In plasma processing equipment used in various fields, such as surface modification, printing and packaging, electronics, plastics, home appliances, and automotive, the load impedance changes. This causes the fixed-impedance impedance matching circuit to fail to achieve efficient impedance matching between the RF module and the load when the load impedance changes, thus failing to maximize the RF module's energy output and resulting in low circuit lifespan and safety. Utility Model Content

[0004] The main purpose of this invention is to propose an impedance matching circuit and a plasma processing device, which aims to achieve impedance matching between the radio frequency module and the load.

[0005] This invention proposes an impedance matching circuit for use in plasma processing equipment. The plasma processing equipment includes a radio frequency (RF) module for connecting a load. The impedance matching circuit is connected in series between the RF module and the load. The impedance matching circuit includes: an inductor adjustment circuit, the input of which is connected to the RF module, and the output of which is connected to the load; a first switching circuit, connected in series between the inductor adjustment circuit and the load; the first switching circuit for turning on / off the path between the inductor adjustment circuit and the load; and a control circuit, the control terminal of which is connected to the first switching circuit. The control circuit controls the first switching circuit to turn on / off the path between the inductor adjustment circuit and the load, thereby achieving impedance matching between the RF module and the load.

[0006] In one embodiment, the inductance adjustment circuit includes: an adjustable inductor connected in series between the RF module and the first switching circuit; and a control circuit for controlling the first switching circuit to turn on / off the path between the adjustable inductor and the load, so as to adjust the inductance value of the adjustable inductor.

[0007] In one embodiment, the impedance matching circuit further includes a capacitor module and an inductor module; the capacitor module and the inductor module are connected in series; the capacitance value of the capacitor module is adjustable; and / or, the inductance value of the inductor module is adjustable.

[0008] In one embodiment, the inductor module includes an inductor and a second switching circuit, the inductor and the second switching circuit being connected in parallel; the control circuit is connected to the second switching circuit; the control circuit is further configured to control the on / off state of the second switching circuit to adjust the inductance value of the inductor module.

[0009] In one embodiment, the inductor module includes at least two inductors connected in series and a number of second switching circuits equal to the number of inductors; each second switching circuit is connected in parallel with each inductor; the control circuit is connected to each second switching circuit; the control circuit is further configured to control the on / off state of each second switching circuit to adjust the inductance value of the inductor module.

[0010] In one embodiment, the capacitor module includes at least two capacitors connected in parallel and a third switching circuit of the same number as the capacitors; each of the third switching circuits is connected in series with each of the capacitors; the control circuit is connected to each of the third switching circuits; the control circuit is also used to control the on / off state of each of the third switching circuits to adjust the capacitance value of the capacitor unit.

[0011] In one embodiment, the impedance matching circuit further includes: an impedance detection circuit, the input terminal of which is connected to the load; the impedance detection circuit is used to detect the inductance of the load; the input terminal of the control circuit is connected to the impedance detection circuit; the control circuit is specifically used to adjust the inductance of the inductance adjustment circuit according to the detection result of the impedance detection circuit, so as to achieve impedance matching between the RF module and the load.

[0012] This invention also proposes a plasma processing device, including a radio frequency module and the impedance matching circuit mentioned above.

[0013] This invention proposes an impedance matching circuit and a plasma processing device. The plasma processing device includes a radio frequency (RF) module for connecting to a load. An impedance matching circuit is connected in series between the RF module and the load. The impedance matching circuit includes: an inductor adjustment circuit, the input of which is connected to the RF module, and the output of which is connected to the load; a first switching circuit, connected in series between the inductor adjustment circuit and the load; a first switching circuit for turning on / off the path between the inductor adjustment circuit and the load; and a control circuit, the control terminal of which is connected to the first switching circuit. The control circuit controls the first switching circuit to turn on / off the path between the inductor adjustment circuit and the load, thereby achieving impedance matching between the RF module and the load. This invention adjusts the impedance of the RF module by adjusting the inductance of the inductor adjustment circuit, thus achieving impedance matching between the RF module and the load, maximizing the energy of the RF module, and improving the lifespan, flexibility, and safety of the impedance matching circuit. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0015] Figure 1 This is a circuit flowchart of an impedance matching circuit and a plasma processing device according to the present invention.

[0016] Figure 2 This is a circuit flowchart of another embodiment of the impedance matching circuit and plasma processing equipment of this utility model;

[0017] Figure 3 This is a circuit structure diagram of the inductor module in an impedance matching circuit according to the present invention.

[0018] Figure 4This is a circuit structure diagram of another embodiment of the inductor module in the impedance matching circuit of this utility model;

[0019] Figure 5 This is a circuit structure diagram of the capacitor module in an impedance matching circuit according to this utility model.

[0020] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0023] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0024] Furthermore, in this utility model, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0025] Understandably, in plasma processing technology, such as thin film preparation and cleaning in microelectronics, the high-frequency microwave signal emitted by the radio frequency (RF) module in the plasma processing equipment is applied to the reactant gas in the vacuum chamber through a matching network, causing it to ionize and generate plasma. Changes in process parameters such as chamber pressure and gas flow rate can lead to load impedance fluctuations, causing impedance mismatch and consequently increasing reflected power. This can not only damage internal components of the RF module but also cause glow discharge instability, affecting the performance of the processed products. Therefore, when there is impedance mismatch between the RF module and the load, some energy will be reflected, preventing the RF energy from being fully utilized, reducing circuit efficiency, and even shortening circuit lifespan. To solve these problems, automatic impedance matching technology is needed to ensure plasma stability and rapid impedance matching, thereby improving processing quality and efficiency. Implementing automatic impedance matching technology through impedance matching circuits ensures that the high-frequency microwave signal from the plasma processing equipment can be smoothly transmitted to the load point, with almost no signal reflection back to the source point, thus improving energy efficiency. When the internal resistance of the signal source is equal in magnitude and phase to the characteristic impedance of the transmission line, or when the characteristic impedance of the transmission line is equal in magnitude and phase to the impedance of the connected load, the input or output terminal of the plasma processing equipment's transmission line can be considered to be in an impedance-matched state. This state is crucial for reducing signal loss and improving signal quality.

[0026] However, when using impedance matching circuits to achieve automatic impedance matching, the load impedance is usually assumed to be fixed. The impedance of the impedance matching circuit is adjusted based on this fixed load impedance, resulting in a fixed impedance for the circuit itself. In plasma processing equipment used in various fields, such as surface modification, printing and packaging, electronics, plastics, home appliances, and automotive, the load impedance changes. This causes the fixed-impedance impedance matching circuit to fail to achieve efficient impedance matching between the RF module and the load when the load impedance changes, thus failing to maximize the RF module's energy output and resulting in low circuit lifespan and safety.

[0027] Therefore, to improve the flexibility of the impedance matching circuit and achieve impedance matching between the RF module and the load, this invention proposes an impedance matching circuit for use in plasma processing equipment. The plasma processing equipment includes an RF module for connecting to the load, and the impedance matching circuit is connected in series between the RF module and the load. (Refer to...) Figure 1 The impedance matching circuit includes:

[0028] The inductor adjustment circuit 10 has its input terminal connected to the radio frequency module and its output terminal connected to the load.

[0029] The first switching circuit 20 is connected in series between the inductance adjustment circuit 10 and the load; the first switching circuit 20 is used to turn on / off the path between the inductance adjustment circuit 10 and the load.

[0030] The control circuit 30 has its control terminal connected to the first switching circuit 20. The control circuit 30 is used to control the first switching circuit 20 to turn on / off the path between the inductor regulation circuit 10 and the load, so as to change the direction of the current output to the inductor regulation circuit 10.

[0031] It is understandable that impedance matching is a crucial technical aspect in plasma processing equipment. While impedance matching circuits can achieve automatic impedance matching, ensuring that high-frequency microwave signals from the plasma processing equipment are smoothly transmitted to the load point with minimal signal reflection back to the source, thus improving energy efficiency, impedance matching circuits typically assume a fixed load impedance during matching. This results in a fixed impedance for the impedance matching circuit itself. However, when applied in different scenarios, the load impedance changes, causing the fixed-impedance impedance matching circuit to fail to achieve efficient impedance matching. Consequently, it cannot maximize the energy output of the RF module, and the circuit's lifespan and safety are reduced. This invention proposes an impedance matching circuit that adjusts the inductance of the inductor adjustment circuit 10 to adjust the impedance of the RF module, achieving impedance matching between the RF module and the load, maximizing the RF module's energy output, and improving the lifespan, flexibility, and safety of the impedance matching circuit.

[0032] In this embodiment, the impedance matching circuit is applied in a plasma processing device, which includes a radio frequency (RF) module. The RF module is mainly used to transmit high-frequency microwave signals to generate high-voltage, high-frequency energy. The high-voltage, high-frequency energy is activated and controlled to form a glow discharge, thereby forming low-temperature plasma. The low-temperature plasma interacts with the load surface through surface cleaning and activation to remove mold release agents and additives from the load surface, significantly improving the surface properties of the load. The load can be materials such as polymers, metals, semiconductors, rubber, and PCB circuit boards. Furthermore, the impedance matching circuit includes an inductor adjustment circuit 10 and a control circuit 30. The internal structure of the inductor adjustment circuit 10 consists of a coil and a magnetic chip. When current passes through the inductor adjustment circuit 10, a magnetic field is generated around it. The magnetic field is proportional to the current, generating inductance. The magnetic flux between the coil and the magnetic chip can be changed using the saturation inductance method, the orthogonal core control inductance method, or the switch control inductance method, thereby changing the inductance of the inductor. Furthermore, the first switching circuit 20 is implemented using a bidirectional thyristor, which includes two control electrodes S1 and S2. When the control circuit 30 applies a trigger pulse to either control electrode S1 or S2, the bidirectional thyristor forms a forward or reverse current path, thereby controlling the direction of current flow. With this configuration, the bidirectional conduction capability of the bidirectional thyristor can be used to control the output of the high-frequency microwave signal from the RF module to the load, or to prevent the output of the high-frequency microwave signal from the RF module to the load.

[0033] In practical applications, impedance matching circuits change the inductance of an inductor by controlling it with a switch. Specifically, the control circuit 30 applies a trigger pulse to the control electrode S1 or S2 of the bidirectional thyristor to control the bidirectional thyristor to form a forward or reverse current path, thereby turning on / off the path between the inductor adjustment circuit 10 and the load, regulating the current flowing through the inductor adjustment circuit 10. This change in current alters the magnetic field strength around the inductor adjustment circuit 10, which in turn changes the inductance of the inductor adjustment circuit 10. It's important to understand that impedance is the degree to which a circuit impedes alternating current; impedance includes resistance and reactance. A larger inductance stores more energy and thus impedes changes in current; a smaller inductance stores less energy and impedes changes in current less. Therefore, the impedance of the inductor adjustment circuit 10 is directly proportional to its inductance. When the inductance of the inductor adjustment circuit 10 increases, the resistance to current changes increases, and the impedance of the inductor adjustment circuit 10 also increases accordingly. Conversely, when the inductance of the inductor adjustment circuit 10 decreases, the resistance to current changes decreases, and the impedance of the inductor adjustment circuit 10 also decreases accordingly. Therefore, when the inductance of the inductor adjustment circuit 10 changes, its impedance also changes accordingly. By adjusting the inductance of the inductor adjustment circuit 10, its impedance is adjusted, thus achieving impedance matching between the RF module and the load. This embodiment uses a switch-controlled inductor method, where the inductance of the inductor is changed by controlling the switching transistor's on and off states through the control circuit 30. Based on the fast response and precise control of the switching transistor, the magnetic field distribution in the inductor is adjusted by controlling the switching state of the transistor, thereby achieving inductance adjustment.

[0034] This invention proposes an impedance matching circuit and a plasma processing device. The plasma processing device includes a radio frequency (RF) module for connecting to a load. An impedance matching circuit is connected in series between the RF module and the load. The impedance matching circuit includes: an inductor adjustment circuit 10, the input of which is connected to the RF module, and the output of which is connected to the load; a first switching circuit 20, connected in series between the inductor adjustment circuit 10 and the load; the first switching circuit 20 for turning on / off the path between the inductor adjustment circuit 10 and the load; and a control circuit 30, the control terminal of which is connected to the first switching circuit 20; the control circuit 30 for controlling the first switching circuit 20 to turn on / off the path between the inductor adjustment circuit 10 and the load, thereby achieving impedance matching between the RF module and the load. This invention adjusts the impedance of the RF module by adjusting the inductance of the inductor adjustment circuit 10, thereby achieving impedance matching between the RF module and the load, maximizing the energy of the RF module, and improving the lifespan, flexibility, and safety of the impedance matching circuit.

[0035] In one embodiment, reference is made to Figure 2 The inductor adjustment circuit 10 includes:

[0036] An adjustable inductor L1 is connected in series between the RF module and the first switching circuit 20; a control circuit 30 is used to control the first switching circuit 20 to turn on / off the path between the adjustable inductor L1 and the load, so as to adjust the inductance value of the adjustable inductor L1.

[0037] It is understood that in this embodiment, the inductor adjustment circuit 10 is implemented using an adjustable inductor L1, and the first switching circuit 20 is implemented using a bidirectional thyristor. Specifically, the control circuit 30 applies a trigger pulse to the control electrode S1 or S2 of the bidirectional thyristor to control the bidirectional thyristor to form a forward or reverse current path, thereby turning on or off the path between the adjustable inductor L1 and the load. At this time, the high-frequency microwave signal output by the RF module to the adjustable inductor L1 changes, causing a change in the current of the adjustable inductor L1. The change in the current of the adjustable inductor L1 causes a change in the magnetic field strength around the adjustable inductor L1, and the change in the magnetic field strength around the adjustable inductor L1 causes a change in the inductance of the adjustable inductor L1. Since the impedance of the adjustable inductor L1 is proportional to its inductance, when the inductance of the adjustable inductor L1 changes, its impedance also changes accordingly. Therefore, by adjusting the inductance of the adjustable inductor L1, impedance matching between the RF module and the load is achieved.

[0038] In one embodiment, reference is made to Figure 2 The inductor adjustment circuit 10 also includes a capacitor module 50 and an inductor module 40;

[0039] Capacitor module 50 and inductor module 40 are connected in series;

[0040] The capacitance value of capacitor module 50 is adjustable; and / or, the inductance value of inductor module 40 is adjustable.

[0041] It is understood that the inductor adjustment circuit 10 is specifically composed of a capacitor module 50 and an inductor module 40, which are connected in series. When the input terminal of the capacitor module 50 is the input terminal of the inductor adjustment circuit 10, the output terminal of the inductor module 40 is the output terminal of the inductor adjustment circuit 10; when the input terminal of the inductor module 40 is the input terminal of the inductor adjustment circuit 10, the output terminal of the capacitor module 50 is the output terminal of the inductor adjustment circuit 10.

[0042] In this embodiment, the RF module and the load have a first connection path and a second connection path. The RF module, inductor adjustment circuit 10, first switching circuit 20, and load are connected in series through the first connection path, and the RF module, capacitor module 50, inductor module 40, and load are connected in series through the second connection path. In practical applications, the inductor module 40 and capacitor module 50 have three operating states: the inductor module 40 is adjustable, and the capacitor module 50 is not adjustable; or, the inductor module 40 is not adjustable, and the capacitor module 50 is adjustable; or both the inductor module 40 and capacitor module 50 are adjustable. The specific processes for the three operating states are as follows:

[0043] When the inductor module 40 is adjustable and the capacitor module 50 is not adjustable, the inductor module 40 is equipped with an inductor and a switching circuit. The switching circuit is connected in parallel with the inductor, and the controlled terminal of the switching circuit is connected to the control terminal of the control circuit 30. The control circuit 30 sends a control signal to the switching circuit to control the switching circuit to be turned on / off, thereby controlling the inductor to be short-circuited / not short-circuited, thereby changing the inductance value of the inductor.

[0044] When the inductor module 40 is not adjustable and the capacitor module 50 is adjustable, the capacitor module 50 is equipped with a capacitor and a switching circuit. The switching circuit and the capacitor are connected in series, and the controlled terminal of the switching circuit is connected to the control terminal of the control circuit 30. The control circuit 30 sends a control signal to the switching circuit to control the switching circuit to be turned on / off, thereby controlling the capacitor to be open / closed, thus changing the capacitance value of the capacitor.

[0045] With both inductor module 40 and capacitor module 50 adjustable, inductor module 40 is equipped with an inductor and a switching circuit, and capacitor module 50 is equipped with a capacitor and a switching circuit. The switching circuit in inductor module 40 is connected in parallel with the inductor, and the switching circuit in capacitor module 50 is connected in series with the capacitor. Control circuit 30 sends a control signal to the switching circuit in inductor module 40 to adjust the inductance value; similarly, control circuit 30 sends a control signal to the switching circuit in capacitor module 50 to adjust the capacitance value.

[0046] In one embodiment, reference is made to Figure 3 The inductor module 40 includes an inductor and a second switching circuit, wherein the inductor and the second switching circuit are connected in parallel.

[0047] The control circuit 30 is connected to the second switching circuit; the control circuit 30 is also used to control the on / off state of the second switching circuit to adjust the inductance value of the inductor module 40.

[0048] It is understood that in this embodiment, the inductor module 40 includes an inductor L2 and a second switching circuit, which is implemented using a relay K2. The input terminal of the inductor L2 is the input terminal of the inductor module 40, and the output terminal of the inductor L2 is the output terminal of the inductor module 40. The first terminal of the relay K2 is connected to the input terminal of the inductor L2, the second terminal of the relay K2 is connected to the output terminal of the inductor L2, and the controlled terminal of the relay K2 is connected to the control terminal of the control circuit 30.

[0049] In practical applications, the control circuit 30 sends a control signal to the relay K2 to control the relay K2 to close / open, thereby controlling whether the inductor L2 is short-circuited or not. When the inductor L2 is short-circuited, the inductance value of the inductor L2 changes accordingly. Since the impedance of the inductor L2 is proportional to its inductance, when the inductance of the inductor L2 increases, its impedance also increases; when the inductance of the inductor L2 decreases, its impedance also decreases. Therefore, when the inductance of the inductor L2 changes, its impedance also changes. By adjusting the inductance of the inductor L2, the impedance of the inductor L2 is adjusted, achieving impedance matching between the RF module and the load.

[0050] In one embodiment, reference is made to Figure 4 The inductor module 40 includes at least two inductors connected in series and a second switching circuit of the same number as the inductors; each second switching circuit is connected in parallel with each inductor.

[0051] The control circuit 30 is connected to each of the second switching circuits; the control circuit 30 is also used to control the on / off state of each of the second switching circuits to adjust the inductance value of the inductor module 40.

[0052] It is understood that multiple inductors L2 in the inductor module 40 can be configured to expand the amplitude range of the adjustable impedance and more precisely adjust the inductance value of inductor L2, thereby adjusting the impedance of inductor L2. In this embodiment, the inductor module 40 includes at least two inductors L2 connected in series. The number of second switching circuits is the same as the number of inductors L2, and the second switching circuits are implemented using relays K2. Each relay K2 is connected in parallel with each inductor L2, and the controlled terminal of each relay K2 is connected to the control terminal of the control circuit 30. The output terminal of at least one of the multiple inductors L2 is the output terminal of the inductor module 40.

[0053] In practical applications, the control circuit 30 simultaneously sends control signals to multiple relays K2 to control the closing / opening of the relays K2, thereby controlling the short circuit / non-short circuit of multiple inductors L2. When multiple inductors L2 are short-circuited, their inductance values ​​change accordingly. Since the impedance of an inductor L2 is proportional to its inductance, when the inductance of an inductor L2 increases, its impedance also increases; when the inductance of an inductor L2 decreases, its impedance also decreases. Therefore, when the inductance of multiple inductors L2 changes, their impedance also changes. By adjusting the inductance of multiple inductors L2, their impedance can be adjusted more precisely, achieving impedance matching between the RF module and the load.

[0054] In one embodiment, reference is made to Figure 5 The capacitor module 50 includes at least two capacitors connected in parallel and a third switching circuit of the same number as the capacitors; each third switching circuit is connected in series with each capacitor.

[0055] The control circuit 30 is connected to each third switch circuit; the control circuit 30 is also used to control the on / off state of each third switch circuit to adjust the capacitance value of the capacitor unit.

[0056] It is understood that the capacitor module 50 includes capacitor C1 and a third switching circuit. Multiple capacitors C1 can be used to expand the range of impedance adjustment and more precisely adjust the capacitance value of C1, thereby adjusting the impedance of inductor L2. In this embodiment, the capacitor module 50 includes at least two capacitors connected in parallel. The number of third switching circuits is the same as the number of capacitors C1, and the third switching circuit is implemented using relays K3. Each relay K3 is connected in series with each capacitor C1, and the controlled terminal of each relay K3 is connected to the control terminal of the control circuit 30. The input terminals of multiple capacitors C1 are interconnected, and their interconnection point is the input terminal of the capacitor module 50. The output terminals of multiple capacitors C1 are interconnected, and their interconnection point is the output terminal of the capacitor module 50.

[0057] In practical applications, the control circuit 30 simultaneously sends control signals to multiple relays K3 to control the closing / opening of these relays, thereby controlling the open / closed circuit of multiple capacitors C1. When multiple capacitors C1 are open-circuited, their capacitance values ​​change accordingly. Since the impedance of capacitor C1 is inversely proportional to its capacitance, when the capacitance of capacitor C1 increases, its impedance decreases; conversely, when the capacitance of capacitor C1 decreases, its impedance increases. Therefore, when the capacitance values ​​of multiple capacitors C1 change, their impedance also changes. By adjusting the capacitance values ​​of multiple capacitors C1, their impedance can be adjusted more precisely, achieving impedance matching between the RF module and the load.

[0058] In one embodiment, reference is made to Figure 2The impedance matching circuit also includes:

[0059] Impedance detection circuit 60, the input terminal of impedance detection circuit 60 is connected to the load; impedance detection circuit 60 is used to detect the inductance of the load.

[0060] The input terminal of the control circuit 30 is connected to the impedance detection circuit 60; the control circuit 30 is specifically used to adjust the inductance of the inductance adjustment circuit 10 according to the detection result of the impedance detection circuit 60, so as to achieve impedance matching between the RF module and the load.

[0061] It is understood that in this embodiment, the impedance matching circuit also includes an impedance detection circuit 60. The impedance detection circuit 60 detects the load impedance, and the control module can obtain the load impedance value based on the detection result. It then calculates the load inductance value based on the relationship between impedance and inductance, and controls the first switching circuit 20 to adjust the inductance of the impedance matching circuit, thereby adjusting the impedance of the impedance matching circuit. Even if the load impedance changes, the impedance of the impedance matching circuit can be readjusted, effectively reducing RF reflection power, maximizing the energy of the RF module, and ensuring the lifespan and safety of the plasma processing equipment.

[0062] The above are merely optional embodiments of this utility model and do not limit the patent scope of this utility model. All equivalent structural transformations made based on the contents of this utility model specification and drawings under the utility model concept, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this utility model.

Claims

1. An impedance matching circuit, applied in plasma processing equipment, characterized in that, The plasma processing equipment includes a radio frequency (RF) module for connecting a load. An impedance matching circuit is connected in series between the RF module and the load. The impedance matching circuit includes: An inductor adjustment circuit, wherein the input terminal of the inductor adjustment circuit is connected to the radio frequency module, and the output terminal of the inductor adjustment circuit is connected to the load; A first switching circuit is connected in series between the inductor adjustment circuit and the load; the first switching circuit is used to turn on / off the path between the inductor adjustment circuit and the load. A control circuit, the control terminal of which is connected to the first switching circuit; the control circuit is used to control the first switching circuit to turn on / off the path between the inductor adjustment circuit and the load, so as to achieve impedance matching between the RF module and the load.

2. The impedance matching circuit as described in claim 1, characterized in that, The inductor adjustment circuit includes: An adjustable inductor is connected in series between the RF module and the first switching circuit; the control circuit is used to control the first switching circuit to turn on / off the path between the adjustable inductor and the load, so as to adjust the inductance value of the adjustable inductor.

3. The impedance matching circuit as described in claim 1, characterized in that, The impedance matching circuit also includes a capacitor module and an inductor module; The capacitor module and the inductor module are connected in series; The capacitance value of the capacitor module is adjustable; and / or, the inductance value of the inductor module is adjustable.

4. The impedance matching circuit as described in claim 3, characterized in that, The inductor module includes an inductor and a second switching circuit, wherein the inductor and the second switching circuit are connected in parallel. The control circuit is connected to the second switching circuit; the control circuit is also used to control the on / off state of the second switching circuit to adjust the inductance value of the inductor module.

5. The impedance matching circuit as described in claim 3, characterized in that, The inductor module includes at least two inductors connected in series and a second switching circuit of the same number as the inductors; each of the second switching circuits is connected in parallel with each of the inductors. The control circuit is connected to each of the second switching circuits respectively; the control circuit is also used to control the on / off state of each of the second switching circuits to adjust the inductance value of the inductor module.

6. The impedance matching circuit as described in claim 3, characterized in that, The capacitor module includes at least two capacitors connected in parallel and a third switching circuit of the same number as the capacitors; each of the third switching circuits is connected in series with each of the capacitors. The control circuit is connected to each of the third switching circuits; the control circuit is also used to control the on / off state of each of the third switching circuits to adjust the capacitance value of the capacitor unit.

7. The impedance matching circuit as described in claim 1, characterized in that, The impedance matching circuit further includes: An impedance detection circuit, the input terminal of which is connected to the load; the impedance detection circuit is used to detect the inductance of the load. The input terminal of the control circuit is connected to the impedance detection circuit; specifically, the control circuit is used to adjust the inductance of the inductance adjustment circuit according to the detection result of the impedance detection circuit, so as to achieve impedance matching between the RF module and the load.

8. A plasma processing device, characterized in that, It includes an RF module and an impedance matching circuit as described in any one of claims 1-7.

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