A multi-load automatic impedance matching system

Abstract

This invention proposes a multi-load automatic impedance matching system, comprising a matching network including adjustable elements; a signal acquisition and processing unit for real-time acquisition of the transmission power signal of the RF power supply and calculation of the load impedance; a control unit connected to the signal acquisition and processing unit for generating a first control signal and a second control signal based on the calculated load impedance; a motor adjustment module connected to the control unit for driving the adjustable motor of the adjustable elements according to the first control signal; and an output switching unit connected between the output end of the matching network and at least two output interfaces. The output switching unit is connected to the control unit and controlled by the second control signal, and has multiple operating states. This invention integrates at least four practical output modes through the output switching unit, meeting the needs of various application scenarios without requiring multiple external devices.

Description

Technical Field

[0001] This utility model relates to the field of radio frequency matching technology, specifically, it demonstrates a multi-load automatic impedance matching system. Background Technology

[0002] In radio frequency plasma processes, in order to meet different process requirements, the system needs to be dynamically adjusted to match the wide range of load impedance changes. The operating frequency band, power budget and load complex impedance characteristics of different processes are significantly different, which puts stringent requirements on the flexibility of the output device.

[0003] Using a single matching unit to meet two impedance requirements involves a recalibration process, which increases the complexity of the operation.

[0004] The basic impedance matching modes currently are as follows: Figure 1 As shown, its function is to adjust the matching network to obtain an effective impedance that is conjugate to the internal resistance of the RF source. The effective impedance includes the load impedance and the impedance of the matching network. When the effective impedance and the internal resistance of the RF source are completely equal, the matching is considered complete. This avoids reflections, optimizes the operating performance of the RF source, and ensures the stability of the entire system. Common RF matching network structures are designed to adapt to the target process load requirements in a single case. However, in practical applications, to meet different process requirements, there are two or more load structures. When using only a single matching network, the equipment needs to be disassembled and readjusted for two or more different load requirements, increasing the complexity of operation and reducing overall efficiency.

[0005] In addition, existing dual-output switching solutions have functional limitations: one type is a single-pole double-throw switch, which can only achieve two-way switching of two loads and cannot meet the requirements of parallel drive; the other type is a fixed power divider, which supports two outputs at the same time, but lacks the ability to turn off the path, and it is difficult to balance insertion loss and amplitude imbalance. Utility Model Content

[0006] To address the shortcomings of existing technologies, this utility model provides a multi-load automatic impedance matching system with a simple and practical structure, high functional integration, simple and reliable system, and good scalability and adaptability.

[0007] The technical solution is as follows: A multi-load automatic impedance matching system, connected between an RF power supply and at least two loads, includes: A matching network, which includes adjustable elements for adjusting the impedance matching state; The signal acquisition and processing unit is used to acquire the transmission power signal of the RF power supply in real time and calculate the load impedance. The control unit, connected to the signal acquisition and processing unit, is used to generate a first control signal and a second control signal based on the calculated load impedance. The motor adjustment module, connected to the control unit, is used to drive the adjustable motor with adjustable elements according to the first control signal; An output switching unit is connected between the output of the matching network and at least two output interfaces, wherein the at least two output interfaces are used to connect at least two loads respectively. The output switching unit is connected to the control unit and controlled by the second control signal. It has multiple operating states and is used to selectively connect the output of the matching network to a single output interface, a combination of multiple output interfaces, or disconnect it from all output interfaces.

[0008] In addition, the above embodiments of this utility model may also have the following additional technical features: According to one embodiment of the present invention, the signal acquisition and processing unit includes: The power detection module is used to collect the incident power signal and reflected power signal on the radio frequency power transmission line; The computer signal processing module, connected to the power detection module, is used to receive incident and reflected power signals and calculate the load impedance value.

[0009] The power detection module is specifically responsible for acquiring the raw data of incident / reflected power; the computer signal processing module is responsible for complex impedance calculations. This clear division of functions improves the system's reliability and processing efficiency.

[0010] In one embodiment, the computer signal processing module includes: An interface module is used to receive incident and reflected power signals from the power detection module; The impedance calculation module, connected to the interface module, is used to calculate the load impedance value based on the incident and reflected power signals.

[0011] The interface module is responsible for signal conditioning and standardization, ensuring the data quality of the input impedance calculation module; the impedance calculation module is responsible for algorithm calculation. The internal processing logic of the computer signal processing module is clearly defined, reducing system complexity and improving anti-interference capability and computational accuracy.

[0012] According to one embodiment of this utility model, the control unit includes a switch control module connected to the signal acquisition and processing unit, used to generate the second control signal to control the output switching unit. This makes the control of the adjustable element and the control of the output switching unit independent of each other, without interference, thus improving the accuracy and stability of system control.

[0013] According to one embodiment of the present invention, the output switching unit includes a common switch, a first load switch and a second load switch; The first end of the shared switch is connected to the output end of the matching network, and its second end forms a shared node. The first load switch is connected between the common node and the first output interface; The second load switch is connected between the common node and the second output interface; Multiple operating states can be achieved by controlling the on and off combinations of the common switch, the first load switch, and the second load switch.

[0014] Using only three switching elements, four operating states can be achieved through different on / off combinations. The structure is simple, the cost is low, and the reliability is high.

[0015] In one implementation, the plurality of operating states include: First state: The shared switch and the first load switch are turned on, and the second load switch is turned off, so that the matching network is connected to one of the loads; Second state: The shared switch and the second load switch are turned on, the first load switch is turned off, and the matching network is connected to another load; Third state: The shared switch, the first load switch and the second load switch are all turned on, so that the matching network is connected to two loads at the same time; Fourth state: The common switch, the first load switch and the second load switch are all turned off, disconnecting the matching network from all loads.

[0016] Based on the above technical solution, the common switch, the first load switch, and the second load switch all MOSFET MOSFETs are type-type transistors. Theoretically, the voltage drop after a MOSFET is turned on is zero, resulting in low drive power and avoiding unnecessary power loss due to the matching network. Only a single drive voltage signal is needed, making control convenient. Furthermore, the input impedance of a MOSFET is close to infinite, maximizing voltage division. When used as a switch in static operation, the overall MOSFET structure has low power consumption. In practical applications, this avoids unnecessary circuit design, simplifying the overall circuit structure and facilitating timely observation of problems during verification and testing. Using a MOSFET as a switch also ensures the stability of the overall circuit.

[0017] According to one embodiment of the present invention, the control unit is configured to: record the optimized impedance matching position of the matching network under different operating states as a preset value; when switching to a certain operating state, the control unit preferentially adjusts the adjustment element of the matching network to the corresponding preset value.

[0018] According to one embodiment of this invention, the adjustable element is an adjustable vacuum capacitor. Vacuum capacitors have extremely low losses, which helps to build high-performance matching networks and reduces power losses inherent in the matching network itself.

[0019] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. Functional integration: Through a built-in multi-position switch, it integrates at least four practical output modes (all on, A-channel, B-channel, all off), meeting the needs of various application scenarios without the need for multiple external devices.

[0020] 2. Performance optimization: The built-in matching circuit ensures impedance matching of signal transmission in various switching modes, improves signal transmission efficiency and quality, and reduces the risk of signal attenuation and equipment damage caused by mismatch.

[0021] 3. It has the advantages of high flexibility and high reliability. The output interface can be configured to be the same or different types, which enhances the versatility and applicability of the equipment. The integrated design reduces external wiring and connectors, reducing system complexity and failure rate. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the existing impedance matching mode; Figure 2 This is a system block diagram of a multi-load automatic impedance matching system according to an embodiment of the present invention; Figure 3 This is a structural diagram of a multi-load automatic impedance matching system according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the output switching unit according to an embodiment of the present invention; The relevant labels in the attached diagram are: 1-Signal acquisition and processing unit, 2-Control unit, 3-Motor adjustment module, 4-Matching network, 5-Output switching unit; 11-Power detection module, 12-Computer signal processing module, 121-Interface module, 122-Impedance calculation module, 21-Switch control module, 41-Adjustable element, 51-MOS transistor switch; S1-Common switch, S2-First load switch, S3-Second load switch. Detailed Implementation

[0023] 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.

[0024] Example 1 This utility model embodiment proposes a multi-load automatic impedance matching system, designed to connect between an RF power supply and at least two loads; in this embodiment, two plasma device loads are selected. (See also...) Figure 2 The diagram shown is a system block diagram of a multi-load automatic impedance matching system, which mainly includes a signal acquisition and processing unit 1, a control unit 2, a matching network 4, a motor adjustment module 3, and an output switching unit 5.

[0025] The signal acquisition and processing unit 1 is mainly used to acquire the transmission power signal of the RF power supply in real time and calculate the load impedance. It includes a power detection module 11 and a computer signal processing module 12. The power detection module 11 is the signal acquisition module, used to acquire the incident power signal and reflected power signal on the coaxial transmission line of the RF power supply. The computer signal processing module 12 is electrically connected to the power detection module 11 and is mainly used to receive the incident and reflected power signals and calculate the load impedance value. It includes an interface module 121 and an impedance calculation module 122. Specifically, the interface module 121 is used to receive the incident power signal and reflected power signal from the power detection module 11, while the impedance calculation module 122 is electrically connected to the interface module 121 and is used to calculate the load impedance value based on the incident power signal and reflected power signal.

[0026] Control unit 2 is electrically connected to signal acquisition and processing unit 1, and is mainly used to generate a first control signal and a second control signal based on the load impedance calculated by the impedance calculation module. Control unit 2 includes a switch control module 21, which is connected to signal acquisition and processing unit 1, and is used to generate a second control signal to control the output switching unit. Control unit 2 is configured to record the optimized impedance matching position of the matching network under different working states as a preset value. When switching to a certain working state, control unit prioritizes adjusting the adjustment element of the matching network to the corresponding preset value.

[0027] The matching network 4 includes an adjustable element 41, which is selected as an adjustable vacuum capacitor. In this embodiment, there are two adjustable elements, specifically an adjustable capacitor C1 and an adjustable capacitor C2.

[0028] The motor adjustment module 3 is electrically connected to the control unit 2. It is mainly used to drive the adjustment motor of the adjustable element according to the first control signal generated by the control unit, and the adjustment motor controls the adjustment of the capacitor.

[0029] The output switching unit 5 is connected between the output end of the matching network 4 and the two output interfaces in this embodiment. The two output interfaces are connected to the two plasma device loads mentioned above. The output interface is referred to as output interface A and output interface B below.

[0030] See Figure 3 The diagram shown illustrates the structure of a multi-load automatic impedance matching system. The output switching unit 5 includes three MOS transistor switches 51, namely... MOSFET The output switching unit 5 is electrically connected to the control unit 2 and controlled by the second control signal. That is, the control unit controls the switching of each MOS transistor. The MOS transistor switches are a common switch S1, a first load switch S2 and a second load switch S3.

[0031] Combination Figure 4 The schematic diagram of the output switching unit shown shows that the first end of the common switch S1 is connected to the output end of the matching network, and its second end forms a common node; the first load switch S2 is connected between the common node and the first output interface A; the second load switch S3 is connected between the common node and the second output interface B; by controlling the combination of the on and off states of the common switch S1, the first load switch S2 and the second load switch S3 respectively, multiple working states can be realized, thereby selectively connecting the output end of the matching network to a single output interface, a combination of multiple output interfaces, or disconnecting it from all output interfaces.

[0032] Specifically, the output switching unit can achieve at least the following four operating states: (1) State I (A-channel output mode): Shared switch S1 and first load switch S2 are turned on, and second load switch S3 is turned off, so that the matching network is connected to one of the plasma device loads Z. L1 .

[0033] The output of the matching circuit is made to be connected to the first output interface A and disconnected from the second output interface B. That is, S1 and S2 are kept closed while S3 remains open, achieving the on-mode for output interface A. At this time, the matching circuit achieves a matching effect with the first plasma device load Z. L1 The matching status is recorded, and the current matching position is recorded.

[0034] (2) State II (B-channel output mode): Shared switch S1 and second load switch S3 are turned on, first load switch S2 is turned off, so that the matching network is connected to another plasma device load Z. L2 .

[0035] The output of the matching circuit is made to be connected to the second output interface B and disconnected from the first output interface A. This means that S1 and S3 are kept closed while S2 remains open, achieving the output interface B conduction mode. At this time, the matching circuit achieves a matching effect with the second plasma device load Z. L2 Matching status, recording the current matching position.

[0036] (3) State III (Simultaneous conduction mode): The common switch S1, the first load switch S2 and the second load switch S3 are all turned on, so that the matching network is connected to the two loads at the same time.

[0037] The output of the matching circuit is simultaneously connected to both the first output port A and the second output port B, meaning that S1, S2, and S3 are kept closed simultaneously, achieving a two-port conduction mode. At this time, the matching effect achieved by the matching circuit is that of the plasma load Z... L1 With Z L2 Record the state after parallel connection, and the matching position at this time.

[0038] (4) State IV (Full Disconnect Mode): The common switch S1, the first load switch S2 and the second load switch S3 are all turned off, disconnecting the matching network from all loads.

[0039] Disconnect the output of the matching circuit from both the first output interface A and the second output interface B, that is, keep S1, S2 and S3 in the disconnected state at the same time to realize the two output interfaces disconnected mode; at this time, the matching network is in an unused state.

[0040] In one possible implementation, the signal acquisition and processing unit primarily uses a directional coupler as a power detection module to acquire signals. The acquired analog signals are then converted into digital signals by an ADC and transmitted to the signal acquisition and processing unit FPGA. The FPGA processes the signals to obtain impedance information and records power information. Using the FPGA for processing not only meets current requirements but also reserves space for future upgrades to perform various signal processing operations. To enable the operation of the automatic impedance matching system, the FPGA connects the processed signals to the control unit STM32 via a CAN communication module. The STM32 then controls the stepper motor adjustment module TMC4361 to adjust the capacitance of the adjustable vacuum capacitor in the matching network to meet the matching requirements.

[0041] The overall system controls different states through an output switching unit, i.e., an external switch. The matching position under different matching states is recorded as different preset values. After testing, the switch can be bound to the preset value. Under different states, the matching network can be directly adjusted to different preset values. At the same time, the automatic matching system is used for fine adjustment to match different impedance changes during the matching process.

[0042] The multi-load automatic impedance matching system in this embodiment has the advantages of high flexibility and high reliability. Through a built-in multi-position switching switch, it integrates four practical output modes to meet the needs of various application scenarios. It does not require multiple external devices, and the output interfaces can be configured to be the same or different types, which enhances the versatility and applicability of the device. The integrated design reduces external wiring and connectors, thereby reducing system complexity and failure rate.

[0043] The above descriptions are merely some embodiments of this utility model. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of this utility model, and all such modifications and improvements fall within the protection scope of this utility model.

Claims

1. A multi-load automatic impedance matching system connected between a radio frequency power source and at least two loads, characterized in that, include: Matching network (4), which includes an adjustable element (41) for adjusting the impedance matching state; The signal acquisition and processing unit (1) is used to acquire the transmission power signal of the radio frequency power supply in real time and calculate the load impedance; The control unit (2) is connected to the signal acquisition and processing unit (1) and is used to generate a first control signal and a second control signal based on the calculated load impedance. The motor adjustment module (3) is connected to the control unit (2) and is used to drive the adjustable motor of the adjustable element according to the first control signal; The output switching unit (5) is connected between the output end of the matching network and at least two output interfaces, wherein the at least two output interfaces are used to connect at least two loads respectively. The output switching unit (5) is connected to the control unit (2) and controlled by the second control signal. It has multiple working states and is used to selectively connect the output end of the matching network to a single output interface, a combination of multiple output interfaces, or disconnect it from all output interfaces.

2. A multi-load automatic impedance matching system as claimed in claim 1, wherein, The signal acquisition and processing unit (1) includes: The power detection module (11) is used to collect the incident power signal and reflected power signal on the radio frequency power transmission line; The computer signal processing module (12) is connected to the power detection module (11) and is used to receive incident and reflected power signals and calculate the load impedance value.

3. A multi-load automatic impedance matching system as claimed in claim 2, wherein, The computer signal processing module (12) includes: The interface module (121) is used to receive incident and reflected power signals from the power detection module (11); Impedance calculation module (122) is connected to interface module (121) and is used to calculate load impedance value based on incident and reflected power signals.

4. A multi-load automatic impedance matching system as claimed in claim 1, wherein, The control unit (2) includes a switch control module (21), which is connected to the signal acquisition and processing unit (1) and is used to generate the second control signal to control the output switching unit (5).

5. A multi-load automatic impedance matching system as claimed in claim 1, wherein, The output switching unit (5) includes a common switch (S1), a first load switch (S2) and a second load switch (S3). The first end of the shared switch (S1) is connected to the output end of the matching network (4), and its second end forms a shared node; The first load switch (S2) is connected between the common node and the first output interface; The second load switch (S3) is connected between the common node and the second output interface; Multiple operating states can be achieved by controlling the on and off combinations of the common switch (S1), the first load switch (S2), and the second load switch (S3).

6. The multi-load automatic impedance matching system according to claim 5, characterized in that, The multiple operating states include: First state: The common switch (S1) and the first load switch (S2) are turned on, and the second load switch (S3) is turned off, so that the matching network (4) is connected to one of the loads; Second state: The common switch (S1) and the second load switch (S3) are turned on, and the first load switch (S2) is turned off, so that the matching network (4) is connected to another load; Third state: The common switch (S1), the first load switch (S2) and the second load switch (S3) are all turned on, so that the matching network (4) is connected to two loads at the same time; Fourth state: The common switch (S1), the first load switch (S2) and the second load switch (S3) are all turned off, so that the matching network (4) is disconnected from all loads.

7. A multi-load automatic impedance matching system according to claim 5 or 6, characterized in that, The common switch (S1), the first load switch (S2) and the second load switch (S3) are all MOSFET transistors of the n-channel type.

8. A multi-load automatic impedance matching system as claimed in claim 1, wherein, The control unit (2) is configured to record the optimized impedance matching position of the matching network under different working states as a preset value; when switching to a certain working state, the control unit will preferentially adjust the adjustment element of the matching network to the corresponding preset value.

9. A multiple load automatic impedance matching system as claimed in claim 1, wherein, The adjustable element (41) is an adjustable vacuum capacitor.

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