Digital impedance matching circuit and plasma processing device

Abstract

The present application relates to the technical field of electronic circuits, and provides a digital impedance matching circuit and a plasma processing device. The plasma processing device comprises a radio frequency module, the radio frequency module being used for outputting a radio frequency signal to a load. The digital impedance matching circuit comprises a conversion circuit, a processing circuit, and an impedance matcher. The conversion circuit converts the radio frequency signal of the radio frequency module into a digital signal. The processing circuit calculates actual impedance of the radio frequency module on the basis of the digital signal, compares the actual impedance with preset impedance, and generates a corresponding control signal on the basis of the comparison result. The impedance matcher adjusts the actual impedance of the radio frequency module on the basis of the control signal, so that impedance matching between the radio frequency module and the load is achieved.

Description

Digital impedance matching circuits and plasma processing equipment

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 202411617602.1, filed on November 13, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technical Field

[0004] This application relates to the field of electronic circuit technology, and in particular to a digital impedance matching circuit and a plasma processing device. Background Technology

[0005] In plasma processing technology, the radio frequency (RF) signal emitted by the 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. Automatic impedance matching technology using digital impedance matching circuits ensures that the RF 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. However, when using digital impedance matching circuits for automatic impedance matching, the load impedance is usually assumed to be fixed. The impedance of the digital impedance matching circuit is adjusted based on this fixed load impedance, resulting in a fixed impedance for the digital impedance matching circuit itself. When plasma processing equipment is applied in different fields, such as surface modification, printing and packaging, electronics, plastics, home appliances, and automotive, the load impedance changes. This causes the fixed-impedance digital 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 energy output of the RF module and resulting in low circuit lifespan and safety. Summary of the Invention

[0006] The main objective of this application is to propose a digital impedance matching circuit and a plasma processing device, which aims to achieve impedance matching between the radio frequency module and the load.

[0007] This application proposes a digital impedance matching circuit for use in a plasma processing device. The plasma processing device includes a radio frequency (RF) module for connecting to a load and outputting RF signals to the load. The digital impedance matching circuit includes: a conversion circuit, the input of which is connected to the output of the RF module; the conversion circuit converts the RF signal from the RF module into a digital signal; a processing circuit, the input of which is connected to the output of the conversion circuit; the processing circuit calculates the actual impedance of the RF module based on the digital signal, compares the actual impedance with a preset impedance, and generates a corresponding control signal based on the comparison result; and an impedance matching device, the input of which is connected to both the output of the processing circuit and the output of the RF module, and the output of which is connected to the load; the impedance matching device adjusts the actual impedance of the RF module according to the control signal to achieve impedance matching between the RF module and the load.

[0008] In one embodiment, the conversion circuit includes: a signal acquisition circuit, the input terminal of which is connected to the output terminal of the radio frequency module; the signal acquisition circuit is used to receive the radio frequency signal from the radio frequency module; and an analog-to-digital converter, the input terminal of which is connected to the output terminal of the signal acquisition circuit, the analog-to-digital converter being used to convert the radio frequency signal from the radio frequency module into a digital signal.

[0009] In one embodiment, the processing circuit includes: an impedance calculator, the input of which is connected to the output of the conversion circuit; the impedance calculator is used to calculate the actual impedance of the radio frequency module based on the digital signal; a signal generator, the input of which is connected to the output of the impedance calculator, and the output of which is connected to the input of the impedance matching circuit; the signal generator is used to compare the actual impedance with a preset impedance and generate a corresponding control signal based on the comparison result.

[0010] In one embodiment, the processing circuit further includes: a digital-to-analog converter, the input terminal of which is connected to the output terminal of the signal generator, and the output terminal of which is connected to the input terminal of the impedance matching device; the digital-to-analog converter is used to convert the control signal of the signal generator into an analog control signal and output the analog control signal to the impedance matching device.

[0011] In one embodiment, the processing circuit further includes: a memory connected to the impedance calculator and the signal generator respectively; the memory is used to store a preset impedance database; the impedance calculator is also used to store the actual impedance of the radio frequency module in the memory; the signal generator is also used to call the preset impedance database in the memory and compare the actual impedance with the preset impedance.

[0012] In one embodiment, the impedance matching device includes: a programmable impedance regulator, the input terminal of which is electrically connected to the output terminal of the processing circuit and the output terminal of the radio frequency module, respectively, and the output terminal of which is electrically connected to the load; the programmable impedance regulator is used to adjust the actual impedance of the radio frequency module according to the control signal so as to achieve impedance matching between the radio frequency module and the load.

[0013] In one embodiment, the digital impedance matching circuit further includes: a feedback circuit, the input terminal of which is connected to the output terminal of the impedance matching device, and the output terminal of which is connected to the input terminal of the processing circuit; the feedback circuit is used to acquire the impedance of the impedance matching device according to a preset period, compare the impedance of the impedance matching device with a preset impedance, and generate a corresponding feedback signal to the processing circuit based on the comparison result.

[0014] In one embodiment, the digital impedance matching circuit further includes: an amplifier circuit, the input terminal of which is connected to the output terminal of the radio frequency module, and the output terminal of which is connected to the input terminal of the conversion circuit; the amplifier circuit is used to amplify the radio frequency signal of the radio frequency module and output it to the conversion circuit.

[0015] This application also proposes a plasma processing device, which includes a radio frequency module and the digital impedance matching circuit.

[0016] This application discloses a digital impedance matching circuit and a plasma processing device, relating to the field of electronic circuit technology. The plasma processing device includes a radio frequency (RF) module for outputting RF signals to a load. The digital impedance matching circuit includes a conversion circuit, a processing circuit, and an impedance matching device. The conversion circuit converts the RF signal from the RF module into a digital signal; the processing circuit calculates the actual impedance of the RF module based on the digital signal, compares the actual impedance with a preset impedance, and generates a corresponding control signal based on the comparison result; the impedance matching device adjusts the actual impedance of the RF module according to the control signal to achieve impedance matching between the RF module and the load. This application achieves impedance matching between the RF module and the load through digital control, featuring high precision, high flexibility, and high stability, providing higher signal transmission efficiency and cost-effectiveness in plasma processing equipment. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application 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 application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 is a circuit flowchart of the digital impedance matching circuit and plasma processing equipment of this application;

[0019] Figure 2 is a circuit flowchart of another embodiment of the digital impedance matching circuit and plasma processing device of this application.

[0020] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Embodiments of the present invention

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

[0022] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application 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 application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" 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 expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0024] Furthermore, the use of terms such as "first" and "second" in this application is 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 as "first" or "second" may explicitly or implicitly include at least one of those features. 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. If 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 in this application.

[0025] Understandably, in plasma processing technologies, such as thin film preparation and cleaning in microelectronics, the radio frequency (RF) signal emitted by the 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 utilized to its fullest potential, 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 RF 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 connected 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 technology, 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. When plasma processing equipment is applied 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. Consequently, the RF module's energy cannot be maximized, and the circuit's lifespan and safety are reduced.

[0027] Therefore, in order to improve the flexibility of the impedance matching circuit and enable impedance matching between the RF module and the load, this application proposes an impedance matching circuit for use in a plasma processing device. The plasma processing device includes an RF module, which is used to connect to the load and output an RF signal to the load. Referring to Figure 1, the digital impedance matching circuit includes:

[0028] The conversion circuit 20 has its input terminal connected to the output terminal of the RF module; the conversion circuit 20 is used to convert the RF signal from the RF module into a digital signal.

[0029] The processing circuit 30 has its input terminal connected to the output terminal of the conversion circuit 20. The processing circuit 30 is used to calculate the actual impedance of the RF module based on the digital signal, compare the actual impedance with the preset impedance, and generate a corresponding control signal based on the comparison result.

[0030] Impedance matching device 10 has its input terminals connected to the output terminals of processing circuit 30 and RF module, respectively, and its output terminal connected to the load. Impedance matching device 10 is used to adjust the actual impedance of RF module according to control signal so as to achieve impedance matching between RF module and load.

[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 the radio frequency (RF) signal from the plasma processing equipment is smoothly transmitted to the load point with minimal signal reflection back to the source, thus improving energy efficiency, some impedance matching circuits have relatively fixed impedance adjustment ranges. These circuits adapt to different load impedance matching requirements by switching different settings or setting different parameter combinations. However, this adjustment method is relatively limited and cannot respond to changes in real time like dynamic adjustment. Furthermore, when impedance matching circuits are applied in different scenarios, the load impedance changes, causing fixed-impedance impedance matching circuits to fail to achieve efficient impedance matching when the load impedance changes. This results in the inability to maximize the energy of the RF module, and also reduces the circuit's lifespan and safety. This application proposes a digital impedance matching circuit that achieves impedance matching between the RF module and the load through digital control, improving signal transmission efficiency and reducing signal loss.

[0032] In this embodiment, a digital impedance matching circuit is applied in a plasma processing device. The plasma processing device includes a radio frequency (RF) module for transmitting RF signals. Specifically, the RF signals generate high-voltage, high-frequency energy, which is activated and controlled to form a glow discharge, thereby creating low-temperature plasma. The low-temperature plasma interacts with the load surface through surface cleaning and activation to remove mold release agents and additives, significantly improving the surface properties of the load. The load can be materials such as polymers, metals, semiconductors, rubber, or PCB circuit boards. In practical applications, the digital impedance matching circuit includes a conversion circuit 20, a processing circuit 30, and an impedance matching device 10. During the impedance matching process using digital control, the processing circuit 30 needs to receive digital signals and output corresponding control signals to control the impedance matching device 10 to adjust the impedance. Since the radio frequency (RF) signal is an analog signal, the RF signal from the RF module in the conversion circuit 20 is converted into a digital signal for the processing circuit 30 to perform impedance calculations. The processing circuit 30 calculates the actual impedance of the RF module based on the digital signal output from the conversion circuit 20, retrieves the stored preset impedance from the preset impedance database, and compares the calculated actual impedance with the preset impedance. Based on the comparison result, it determines whether to perform impedance matching. For example, if the comparison result indicates that the actual impedance does not match the preset impedance, a control signal is output to control the impedance matching device 10 to perform impedance matching; if the comparison result indicates that the actual impedance matches the preset impedance, a control signal is output to control the impedance matching device 10 not to perform impedance matching. When the impedance matching device 10 determines to perform impedance matching based on the control signal, it adjusts the actual impedance of the connected RF module to achieve impedance matching between the RF module and the load. The preset impedance is an ideal impedance pre-set by the technician. When the actual impedance does not match the preset impedance, it can be considered that the impedance between the RF module and the load has not reached the ideal matching state, and the impedance matching device 10 needs to be controlled for impedance matching.

[0033] Compared to other control methods, such as analog control, switch control, and manual adjustment, digital control offers higher resolution for high-precision impedance matching, rapid response to environmental changes for fast impedance matching, and greater stability to avoid the effects of noise or temperature, achieving stable impedance matching. Therefore, this embodiment employs digital control for impedance matching, characterized by high precision, high flexibility, and high stability, resulting in higher signal transmission efficiency and cost-effectiveness in plasma processing equipment. This embodiment dynamically adjusts the impedance of the RF module through digital control to achieve high-precision impedance matching between the RF module and the load, minimizing signal reflection and loss, and improving signal transmission efficiency between the RF module and the load.

[0034] This application proposes a digital impedance matching circuit for use in plasma processing equipment. The plasma processing equipment includes a radio frequency (RF) module, which connects to a load and outputs RF signals to the load. The digital impedance matching circuit includes a conversion circuit 20, a processing circuit 30, and an impedance matching device 10. The input terminal of the conversion circuit 20 is connected to the output terminal of the RF module; the input terminal of the processing circuit 30 is connected to the output terminal of the conversion circuit 20; the input terminal of the impedance matching device 10 is connected to both the output terminal of the processing circuit 30 and the output terminal of the RF module, and the output terminal of the impedance matching device 10 is connected to the load. In practical applications, the conversion circuit 20 converts the RF signal from the RF module into a digital signal; the processing circuit 30 calculates the actual impedance of the RF module based on the digital signal, compares the actual impedance with a preset impedance, and generates a corresponding control signal based on the comparison result; the impedance matching device 10 adjusts the actual impedance of the RF module according to the control signal to achieve impedance matching between the RF module and the load. This application achieves impedance matching between the RF module and the load through digital control, featuring high precision, high flexibility, and high stability, providing higher signal transmission efficiency and cost-effectiveness in plasma processing equipment.

[0035] In one embodiment, referring to FIG1, the conversion circuit 20 includes:

[0036] The signal acquisition circuit has its input terminal connected to the output terminal of the RF module; the signal acquisition circuit is used to receive the RF signal from the RF module.

[0037] An analog-to-digital converter (ADC) is a device whose input is connected to the output of a signal acquisition circuit. It is used to convert the radio frequency (RF) signals from an RF module into digital signals.

[0038] It is understood that in this embodiment, the conversion circuit 20 includes a signal acquisition circuit and an analog-to-digital converter (ADC). The signal acquisition circuit can be implemented using a connector or other signal acquisition device to receive the radio frequency (RF) signal from the RF module and transmit the acquired RF signal to the ADC. Since the RF signal is an analog signal, the ADC converts the RF signal acquired by the signal acquisition circuit from analog to digital, outputting a corresponding digital signal to the processing circuit 30, which then performs impedance calculations based on the digital signal.

[0039] In one embodiment, referring to FIG1, the processing circuit 30 includes:

[0040] The impedance calculator has its input terminal connected to the output terminal of the conversion circuit 20; the impedance calculator is used to calculate the actual impedance of the RF module based on the digital signal.

[0041] The signal generator's input is connected to the output of the impedance calculator, and the output of the signal generator is connected to the input of the impedance matching circuit 10.

[0042] The signal generator is used to compare the actual impedance with the preset impedance and generate the corresponding control signal based on the comparison result.

[0043] It is understood that in this embodiment, the processing circuit 30 includes an impedance calculator and a signal generator. The impedance calculator calculates the actual impedance according to a specific mathematical formula. The actual impedance is typically represented as a complex number, including a real part (resistance) and an imaginary part (inductance and capacitance), and transmits the actual impedance to the signal generator. The signal generator receives the actual impedance from the impedance calculator, calls a preset impedance database to obtain a stored preset impedance, and compares the calculated actual impedance with the preset impedance. Based on the comparison result, it determines whether to perform an impedance matching operation. If the comparison result indicates that the actual impedance does not match the preset impedance, a control signal is generated to control the impedance matching device 10 to perform the impedance matching operation; if the comparison result indicates that the actual impedance matches the preset impedance, a control signal is generated to control the impedance matching device 10 not to perform the impedance matching operation.

[0044] In one embodiment, referring to FIG1, the processing circuit 30 further includes:

[0045] The input terminal of the digital-to-analog converter is connected to the output terminal of the signal generator, and the output terminal of the digital-to-analog converter is connected to the input terminal of the impedance matching circuit 10.

[0046] A digital-to-analog converter is used to convert the control signals of the signal generator into analog control signals and output the analog control signals to the impedance matching circuit 10.

[0047] Understandably, since the control signal generated by the signal generator is a digital control signal, it needs to be converted from a digital signal to an analog signal, and the converted analog signal is used to trigger the impedance matching device 10 to work. In this embodiment, the digital-to-analog converter receives the digital control signal output by the signal generator and converts the digital control signal from a digital signal to an analog signal to output an analog control signal to the impedance matching device 10, thereby controlling the impedance matching device 10 to perform impedance matching.

[0048] In one embodiment, referring to FIG1, the processing circuit 30 further includes:

[0049] The memory is connected to both the impedance calculator and the signal generator; the memory is used to store the preset impedance database.

[0050] The impedance calculator is also used to store the actual impedance of the RF module in memory; the signal generator is also used to call the preset impedance database in memory and compare the actual impedance with the preset impedance.

[0051] It is understood that in this embodiment, the processing circuit 30 also includes a memory for storing a preset impedance database, which stores preset impedances. In practical applications, the impedance calculator calculates the actual impedance of the RF module based on the digital signal output by the conversion circuit 20, and stores the calculated actual impedance in the memory so that technicians can record and statistically analyze the data of the RF module. Furthermore, the signal generator receives the actual impedance from the impedance calculator, calls the preset impedance database in the memory, retrieves the stored preset impedance from the database, compares the calculated actual impedance with the preset impedance, and determines whether to perform impedance matching based on the comparison result.

[0052] In one embodiment, referring to FIG1, the impedance matching device 10 includes:

[0053] The programmable impedance regulator has its input terminals electrically connected to the output terminals of the processing circuit 30 and the RF module, respectively, and its output terminal electrically connected to the load.

[0054] A programmable impedance regulator is used to adjust the actual impedance of the RF module according to a control signal, so as to achieve impedance matching between the RF module and the load.

[0055] It is understood that the impedance matching circuit 10 is implemented using a programmable impedance regulator, which includes variable elements such as variable capacitors, variable inductors, or digital potentiometers. The input terminal of the microcontroller is connected to the output terminal of the processing circuit 30. The microcontroller stores a preset algorithm, and when it receives the control signal output from the processing circuit 30, it adjusts the parameters of the variable elements according to the preset algorithm. The variable elements are connected in series between the RF module and the load to adjust the impedance between them.

[0056] In this embodiment, a variable element including a digital potentiometer is used as an example for explanation. The processing circuit 30 calculates the actual impedance of the RF module based on the digital signal output by the conversion circuit 20, and calls the preset impedance database to obtain the stored preset impedance. The calculated actual impedance is compared with the preset impedance. If the comparison result indicates that the actual impedance does not match the preset impedance, a control signal is output to the microcontroller to trigger the microcontroller's preset algorithm to change the position of the slider inside the digital potentiometer. This allows for precise adjustment of the digital potentiometer's resistance value, thereby changing the total impedance between the RF module and the load. Once the required impedance is reached, the microcontroller maintains the current setting until the receiving processing circuit 30 outputs a new control signal.

[0057] In another embodiment, when the processing circuit 30 determines that the actual impedance matches the preset impedance based on the comparison result, it outputs a control signal to the microcontroller to trigger the microcontroller not to perform the step of adjusting the digital potentiometer. At this time, the microcontroller maintains the current setting and does not change the position of the slider inside the digital potentiometer until the receiving processing circuit 30 outputs a new control signal. The preset algorithm is an ideal algorithm pre-set by the technician and can be modified according to the load.

[0058] In one embodiment, referring to FIG2, the digital impedance matching circuit further includes:

[0059] Feedback circuit 40, the input terminal of feedback circuit 40 is connected to the output terminal of impedance matching circuit 10, and the output terminal of feedback circuit 40 is connected to the input terminal of processing circuit 30;

[0060] Feedback circuit 40 is used to acquire the impedance of impedance matching device 10 according to a preset period, compare the impedance of impedance matching device 10 with the preset impedance, and generate a corresponding feedback signal to processing circuit 30 based on the comparison result.

[0061] Understandably, in this embodiment, after the impedance matching device 10 adjusts the actual impedance of the RF module, the feedback circuit 40 acquires the impedance-matched RF signal according to a preset period, performs analog-to-digital conversion on the impedance-matched RF signal to obtain a digital output signal, and calculates the actual output impedance after impedance matching based on the digital output signal. The preset period of the feedback circuit 40 can be set by a technician. For example, if the digital impedance matching circuit operates in a variable environment or requires frequent maintenance and adjustment, the preset period can be set to a medium-to-high frequency period, such as once a month or once a week. The feedback circuit 40 stores a preset output impedance. By acquiring the stored preset output impedance, the feedback circuit 40 compares the calculated actual output impedance with the preset output impedance and outputs a feedback signal to the processing circuit 30 based on the comparison result. The processing circuit 30 receives a feedback signal and, based on the feedback signal, determines that the actual output impedance does not match the preset output impedance. When this happens, it outputs a control signal to control the impedance matching device 10 to perform an impedance matching operation. Alternatively, when the processing circuit 30 receives a feedback signal and, based on the feedback signal, determines that the actual output impedance matches the preset output impedance, it outputs a control signal to control the impedance matching device 10 not to perform an impedance matching operation. This enables real-time monitoring of the output impedance.

[0062] In one embodiment, referring to FIG2, the digital impedance matching circuit further includes:

[0063] Amplifier circuit 50, the input terminal of amplifier circuit 50 is connected to the output terminal of RF module, and the output terminal of amplifier circuit 50 is connected to the input terminal of conversion circuit 20;

[0064] Amplifier circuit 50 is used to amplify the radio frequency signal from the radio frequency module and output it to conversion circuit 20.

[0065] Understandably, to ensure accurate sampling by the conversion circuit 20, this embodiment also includes an amplifier circuit 50. The amplifier circuit 50 is positioned between the RF module and the conversion circuit 20 to increase the signal level of the RF module, thereby ensuring accurate sampling by the conversion circuit 20. Furthermore, the amplifier circuit 50 can provide sufficient power to drive the transmission line between the RF module and the conversion circuit 20, thereby improving signal driving capability.

[0066] This application also proposes a plasma processing device, including a radio frequency module and a digital impedance matching circuit. The specific circuit structure of the plasma processing device is as described in the above embodiments. Since the plasma processing device adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here.

[0067] The above are merely embodiments of this application and do not limit the patent scope of this application. Any equivalent structural transformations made based on the content of the specification and drawings of this application under the concept of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A digitized impedance matching circuit applied to a plasma processing apparatus, the plasma processing apparatus comprising a radio frequency module for connecting a load and outputting a radio frequency signal to the load, wherein, The digital impedance matching circuit includes: A conversion circuit, the input terminal of which is connected to the output terminal of the radio frequency module; the conversion circuit is used to convert the radio frequency signal of the radio frequency module into a digital signal; The processing circuit has its input terminal connected to the output terminal of the conversion circuit. The processing circuit is used to calculate the actual impedance of the radio frequency module based on the digital signal, compare the actual impedance with a preset impedance, and generate a corresponding control signal based on the comparison result. An impedance matching device is provided, wherein the input terminal of the impedance matching device is connected to the output terminal of the processing circuit and the output terminal of the RF module, respectively, and the output terminal of the impedance matching device is connected to the load; the impedance matching device is used to adjust the actual impedance of the RF module according to the control signal so as to achieve impedance matching between the RF module and the load.

2. The digitized impedance matching circuit of claim 1, wherein, The conversion circuit includes: A signal acquisition circuit, wherein the input terminal of the signal acquisition circuit is connected to the output terminal of the radio frequency module; the signal acquisition circuit is used to receive the radio frequency signal from the radio frequency module. An analog-to-digital converter (ADC) is provided, the input of which is connected to the output of the signal acquisition circuit. The ADC is used to convert the radio frequency signal of the radio frequency module into a digital signal.

3. The digitized impedance matching circuit of claim 1, wherein, The processing circuit includes: An impedance calculator, the input of which is connected to the output of the conversion circuit; the impedance calculator is used to calculate the actual impedance of the radio frequency module based on the digital signal. A signal generator, the input of which is connected to the output of the impedance calculator, and the output of which is connected to the input of the impedance matching device; The signal generator is used to compare the actual impedance with the preset impedance and generate a corresponding control signal based on the comparison result.

4. The digitized impedance matching circuit of claim 3, wherein, The processing circuit further includes: A digital-to-analog converter, wherein the input terminal of the digital-to-analog converter is connected to the output terminal of the signal generator, and the output terminal of the digital-to-analog converter is connected to the input terminal of the impedance matching circuit; The digital-to-analog converter is used to convert the control signal of the signal generator into an analog control signal and output the analog control signal to the impedance matching circuit.

5. The digitized impedance matching circuit of claim 3, wherein, The processing circuit further includes: The memory is connected to both the impedance calculator and the signal generator; the memory is used to store a preset impedance database. The impedance calculator is also used to store the actual impedance of the radio frequency module in the memory; the signal generator is also used to call the preset impedance database of the memory and compare the actual impedance with the preset impedance.

6. The digitized impedance matching circuit of claim 1, wherein, The impedance matching device includes: A programmable impedance regulator, wherein the input terminal of the programmable impedance regulator is electrically connected to the output terminal of the processing circuit and the output terminal of the radio frequency module, respectively, and the output terminal of the programmable impedance regulator is electrically connected to the load; The programmable impedance regulator is used to adjust the actual impedance of the RF module according to the control signal, so as to achieve impedance matching between the RF module and the load.

7. The digitized impedance matching circuit of claim 1, wherein, The digital impedance matching circuit also includes: A feedback circuit, wherein the input terminal of the feedback circuit is connected to the output terminal of the impedance matching circuit, and the output terminal of the feedback circuit is connected to the input terminal of the processing circuit; The feedback circuit is used to acquire the impedance of the impedance matching device according to a preset period, compare the impedance of the impedance matching device with the preset impedance, and generate a corresponding feedback signal to the processing circuit based on the comparison result.

8. The digitized impedance matching circuit of claim 1, wherein, The digital impedance matching circuit also includes: An amplifier circuit, wherein the input terminal of the amplifier circuit is connected to the output terminal of the radio frequency module, and the output terminal of the amplifier circuit is connected to the input terminal of the conversion circuit; The amplification circuit is used to amplify the radio frequency signal from the radio frequency module and output it to the conversion circuit.

9. A plasma processing apparatus, wherein, The plasma processing equipment includes a radio frequency module and a digital impedance matching circuit as described in any one of claims 1-8.

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