Radio frequency impedance matching device and method

Abstract

The present application relates to a radio frequency impedance matching device and method, the radio frequency impedance matching device comprising: a sensor module, a fractional-order controller, a driving module and a variable impedance circuit. The radio frequency output impedance of the radio frequency generating device and the current impedance of the variable impedance circuit are detected by the sensor module, the current error impedance of the variable impedance circuit is calculated by the fractional-order controller, the adjustment amount of the variable impedance circuit is determined by the fractional-order PID control algorithm, and the variable impedance circuit is driven by the driving module to complete the impedance adjustment so as to match the impedance. The fractional-order PID control algorithm executed in the fractional-order controller is provided with an integral term fractional-order factor and a differential term fractional-order factor, the integral term fractional-order factor affects the steady-state accuracy of the impedance of the variable impedance circuit, and the integral term fractional-order factor affects the overshoot of the impedance of the variable impedance circuit. Therefore, the radio frequency impedance matching device proposed in the present application has a faster matching speed and higher matching accuracy.

Description

Technical Field

[0001] The present application relates to automation control technology, and in particular to a radio frequency impedance matching device and method. Background Art

[0002] A radio frequency (RF) generator is used to generate a radio frequency electrical signal of a specific frequency, can provide radio frequency power, and is used in a variety of scenarios that require radio frequency signals. The RF generator is combined with a plasma chamber to transmit radio frequency power to the plasma chamber, which can stimulate the generation of plasma for processes such as etching and chemical vapor deposition. However, under normal circumstances, the nonlinear load impedance of the plasma chamber is not equal to the constant output impedance of the RF generator, and there will be a serious impedance imbalance between the RF generator and the plasma chamber, resulting in a large amount of reflected power on the RF transmission line between the RF generator and the plasma chamber, causing the power generated by the RF generator to be unable to be fully transmitted to the plasma chamber.

[0003] Therefore, in the conventional technology, a radio frequency impedance matching device is provided between the radio frequency generating device and the plasma chamber to adjust the impedance in the circuit so as to achieve impedance matching. In the implementation process, the inventors found that the conventional radio frequency impedance matching device has the problems of slow matching speed and low matching accuracy. Summary of the invention

[0004] Based on this, it is necessary to provide a radio frequency impedance matching device to address the problem of slow matching speed and low precision.

[0005] On the one hand, in one embodiment, a radio frequency impedance matching device is provided, comprising: a sensor module, a fractional-order controller, a driving module, and a variable impedance circuit;

[0006] The variable impedance circuit is used to connect the radio frequency generating device and the plasma chamber respectively, and the sensor module is used to detect the radio frequency output impedance of the radio frequency generating device and the current impedance of the variable impedance circuit, and transmit them to the fractional order controller;

[0007] The fractional-order controller is connected to the sensor module and the driving module respectively, and is used to obtain the current error impedance of the variable impedance circuit according to the RF output impedance and the current impedance of the variable impedance circuit, and obtain the impedance adjustment amount of the variable impedance circuit based on the fractional-order PID control algorithm, and generate an adjustment instruction according to the impedance adjustment amount and send it to the driving module; the current error impedance is obtained according to the difference between the target impedance of the variable impedance circuit and the current impedance of the variable impedance circuit during impedance matching;

[0008] The driving module is used to adjust the current impedance of the variable impedance circuit according to the adjustment instruction so that the radio frequency output impedance matches the input impedance of the matching network.

[0009] In one embodiment, the fractional-order controller includes an error calculation unit, a fractional-order PID control unit and an instruction generation unit;

[0010] The error calculation unit is connected to the sensor module, and is used to receive the RF output impedance detected by the sensor module and the current impedance of the variable impedance circuit, and use the RF output impedance as the matching network input impedance, and bring it into the preset functional relationship between the variable impedance circuit impedance and the matching network input impedance to obtain the target impedance of the variable impedance circuit when the impedance is matched, and obtain the current error impedance of the variable impedance circuit according to the difference between the target impedance of the variable impedance circuit and the current impedance of the variable impedance circuit;

[0011] The fractional-order PID control unit is connected to the error calculation unit, and is used to bring the current error impedance of the variable impedance circuit into the fractional-order PID control algorithm to obtain the impedance adjustment amount of the variable impedance circuit;

[0012] The instruction generating unit is respectively connected to the fractional-order PID control unit and the driving module, and is used for generating an adjustment instruction according to the impedance adjustment amount and sending the adjustment instruction to the driving module.

[0013] In one embodiment, a variable impedance circuit includes at least one variable impedance element.

[0014] In one embodiment, the variable impedance circuit includes a first variable impedance element and a second variable impedance element;

[0015] The sensor module is used to detect the RF output impedance of the RF generating device, the current impedance of the first variable impedance element and the current impedance of the second variable impedance element, and transmit them to the error calculation unit;

[0016] The error calculation unit is connected to the sensor module, and is used to receive the RF output impedance, the current impedance of the first variable impedance element, and the current impedance of the second variable impedance element detected by the sensor module, and use the RF output impedance as the matching network input impedance, and bring into the preset functional relationship between the impedance of the first variable impedance element, the impedance of the second variable impedance element, and the matching network input impedance, to obtain the target impedance of the first variable impedance element and the target impedance of the second variable impedance element when the impedance is matched, and obtain the current error impedance of the first variable impedance element according to the difference between the target impedance of the first variable impedance element and the current impedance of the first variable impedance element, and obtain the current error impedance of the second variable impedance element according to the difference between the target impedance of the second variable impedance element and the current impedance of the second variable impedance element;

[0017] The fractional-order PID control unit is connected to the error calculation unit, and is used to respectively bring the current error impedance of the first variable impedance element and the current error impedance of the second variable impedance element into the fractional-order PID control algorithm to obtain the impedance adjustment amount of the first variable impedance element and the impedance adjustment amount of the second variable impedance element;

[0018] The instruction generation unit is connected to the fractional-order PID control unit and the driving module respectively, and is used to generate an adjustment instruction according to the impedance adjustment amount of the first variable impedance element and the impedance adjustment amount of the second variable impedance element and send it to the driving module;

[0019] The driving module is used to adjust the current impedance of the first variable impedance element and the current impedance of the second variable impedance element according to the adjustment instruction, so that the radio frequency output impedance matches the input impedance of the matching network.

[0020] In one embodiment, the integral term fractional order factor of the fractional order PID control algorithm is greater than zero, and the derivative term fractional order factor is less than two.

[0021] In one embodiment, the first variable impedance element is a variable inductor or a variable capacitor.

[0022] On the other hand, in one embodiment, a radio frequency impedance matching method is provided, which is applied to the fractional-order controller of claim 1, and is characterized by comprising:

[0023] receiving the radio frequency output impedance of the radio frequency generating device and the current impedance of the variable impedance circuit sent by the sensor module;

[0024] According to the RF output impedance and the variable impedance circuit, a current error impedance of the variable impedance circuit is obtained; the current error impedance is obtained according to the difference between the target impedance of the variable impedance circuit during impedance matching and the current impedance of the variable impedance circuit;

[0025] According to the current error impedance of the variable impedance circuit, based on the fractional-order PID control algorithm, the impedance adjustment amount of the variable impedance circuit is obtained;

[0026] An adjustment instruction is generated according to the impedance adjustment amount and sent to the driving module; the adjustment instruction is used to control the driving module to adjust the impedance of the variable impedance circuit according to the impedance adjustment amount so that the RF output impedance matches the matching network input impedance.

[0027] In one embodiment, the step of obtaining the current error impedance of the variable impedance circuit according to the RF output impedance and the variable impedance circuit includes:

[0028] The RF output impedance is used as the input impedance of the matching network, and is substituted into the functional relationship between the preset variable impedance circuit impedance and the input impedance of the matching network to obtain the target impedance of the variable impedance circuit when the impedance is matched;

[0029] The current error impedance of the variable impedance circuit is obtained according to the difference between the target impedance of the variable impedance circuit and the current impedance of the variable impedance circuit.

[0030] In one embodiment, the variable impedance circuit includes at least one variable impedance element, and before the step of receiving the RF output impedance of the RF generating device and the current impedance of the variable impedance circuit sent by the sensor module, it also includes:

[0031] According to the topological relationship of each variable impedance element, the functional relationship between the input impedance of the matching network and the impedance of each variable impedance element is obtained through modeling.

[0032] In one embodiment, the integral term fractional order factor of the fractional order PID control algorithm is greater than zero, and the derivative term fractional order factor is less than two.

[0033] One of the above technical solutions has the following advantages and beneficial effects:

[0034] The RF output impedance of the RF generating device and the current impedance of the variable impedance circuit are detected by the sensor module, the current error impedance of the variable impedance circuit is calculated by the fractional-order controller, the adjustment amount of the variable impedance circuit is determined by the fractional-order PID control algorithm, and the variable impedance circuit is driven by the driving module to complete the impedance adjustment so that the impedance is matched. In addition to the strong robustness of the traditional PID control algorithm, the fractional-order PID control algorithm executed in the fractional-order controller adds two parameters, the integral term fractional-order factor and the differential term fractional-order factor. The integral term fractional-order factor affects the steady-state accuracy of the impedance of the variable impedance circuit, and the integral term fractional-order factor affects the overshoot of the impedance of the variable impedance circuit. Therefore, the RF impedance matching device proposed in this application has a faster matching speed and higher matching accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic structural diagram of a radio frequency impedance matching device provided for one implementation of the present application. DETAILED DESCRIPTION

[0036] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0037] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to another element and integrated therewith, or there may be an intermediate element at the same time. The terms "installed", "one end", "the other end" and similar expressions used herein are for illustrative purposes only.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0039] In one embodiment, Figure 1 As shown, the present application provides a radio frequency impedance matching device, including: a sensor module 100, a fractional-order controller 200, a driving module 300 and a variable impedance circuit 400;

[0040] The variable impedance circuit 400 is used to connect the RF generator and the plasma chamber respectively, and the sensor module 100 is used to detect the RF output impedance of the RF generator and the current impedance of the variable impedance circuit, and transmit them to the fractional-order controller 200;

[0041] The fractional-order controller 200 is connected to the sensor module 100 and the driving module 300 respectively, and is used to obtain the current error impedance of the variable impedance circuit according to the RF output impedance and the current impedance of the variable impedance circuit, and obtain the impedance adjustment amount of the variable impedance circuit based on the fractional-order PID control algorithm, and generate an adjustment instruction according to the impedance adjustment amount and send it to the driving module 300; the current error impedance is obtained according to the difference between the target impedance of the variable impedance circuit and the current impedance of the variable impedance circuit during impedance matching;

[0042] The driving module 300 is used to adjust the current impedance of the variable impedance circuit according to the adjustment instruction so that the RF output impedance matches the input impedance of the matching network.

[0043] The matching network is a matching network composed of the variable impedance circuit 400 and the plasma chamber, and the impedance is matched when the RF output impedance of the RF generator is equal to the input impedance of the matching network. The RF output impedance of the RF generator is generally fixed, for example, it can be 50 ohms.

[0044] Specifically, the sensor module 100 is set in different ways according to its detection mode. For example, the sensor module 100 can be set on the RF transmission line between the RF generator and the variable impedance circuit 400; the sensor module 100 can be connected to the output end of the RF generator through the first detection end, and connected to the variable impedance circuit 400 through the second detection end. The sensor module 100 outputs the detection result according to the set detection cycle.

[0045] When the time reaches the detection moment, the sensor module 100 detects and outputs the RF output impedance and the current impedance of the variable impedance circuit to the fractional-order controller 200. The fractional-order controller 200 calculates the current error impedance of the variable impedance circuit based on the RF output impedance and the current impedance of the variable impedance circuit through some traditional algorithms in the field, and brings the current error impedance into the fractional-order PID control algorithm to obtain the impedance adjustment amount of the variable impedance circuit. The fractional-order controller 200 adjusts the current impedance of the variable impedance circuit according to the impedance adjustment amount by controlling the driving module 300, and the current impedance of the variable impedance circuit after adjustment will become the current impedance of the variable impedance circuit detected and output by the sensor module 100 when the next detection moment arrives. Because there are many factors causing control errors in actual situations, the current impedance of the variable impedance circuit will not be completely consistent with its target impedance after being adjusted according to the impedance adjustment amount. Therefore, it is necessary to loop the above method until the current error impedance of the variable impedance circuit meets certain conditions, and then determine that the impedance is matched in the current state.

[0046] The impedance of the variable impedance circuit is used as the control object of the fractional-order PID control algorithm, and the impedance matching is used as the control target. It can be understood that the control target in an ideal situation is to make the impedance of the variable impedance circuit stable and equal to the target impedance of the variable impedance circuit, but in reality there will always be control errors, so the control target is the input of the fractional-order PID control algorithm, that is, when the current error of the variable impedance circuit converges within an interval, it is considered that the control target is achieved. In one example, the fractional-order controller: r(t) is the set input; y(t) is the system input; e(t) = r(t)-y(t) is the tracking error, and u(t) is the control input.

[0047] Preferably, in the fractional-order PID control algorithm, the integral term fractional-order factor λ is greater than 0, and the differential term fractional-order factor μ is less than 2, and the transfer formula of the fractional-order PID control algorithm is as follows. p , K i , and K d are proportional, integral and differential gains respectively, λ is the fractional order factor of the integral term and μ is the fractional order factor of the differential term.

[0048]

[0049] The above-mentioned RF impedance matching device detects the RF output impedance of the RF generating device and the current impedance of the variable impedance circuit through the sensor module 100, calculates the current error impedance of the variable impedance circuit through the fractional-order controller 200, uses the fractional-order PID control algorithm to determine the adjustment amount of the variable impedance circuit, and drives the variable impedance circuit 400 through the driving module 300 to complete the impedance adjustment so as to match the impedance. In addition to the strong robustness of the traditional PID control algorithm, the fractional-order PID control algorithm executed in the fractional-order controller 200 adds two parameters, the integral term fractional-order factor and the differential term fractional-order factor. The integral term fractional-order factor affects the steady-state accuracy of the impedance of the variable impedance circuit 400, and the integral term fractional-order factor affects the overshoot of the impedance of the variable impedance circuit 400. Therefore, the RF impedance matching device proposed in this application has a faster matching speed and higher matching accuracy.

[0050] In one embodiment, the variable impedance circuit 400 includes at least one variable impedance element. In another embodiment, the variable impedance element is a variable inductor or a variable capacitor. When the variable impedance circuit 400 includes two variable impedance elements, the two impedance elements can be in parallel or in series.

[0051] The driving module 300 is used to drive and adjust each variable impedance element in the variable impedance circuit 400 .

[0052] The driving module 300 mentioned above changes the driving mode according to the impedance adjustment mode of the variable impedance element. In one embodiment, the impedance adjustment mode of the variable impedance element is to mechanically push and pull the adjustment component set thereon, and the driving module 300 is an electrically driven mechanical device, which drives and adjusts the variable impedance element by mechanical push and pull. In one embodiment, the adjustment mode of the variable impedance element is electrically driven adjustment, and its impedance is adjusted according to the adjustment drive signal of the adjustment port. The driving module 300 is an electrically driven electrical structure device, which is used to generate an adjustment drive signal according to the adjustment instruction output by the fractional-order controller 200.

[0053] In one embodiment, the sensor module 100 includes a sensor and a computing unit that are interconnected. The sensor is used to detect the voltage, current, forward power and reverse power on the RF transmission line between the RF generator and the variable impedance circuit 400. The computing unit is used to calculate the RF output impedance of the RF generator and the current impedance of the variable impedance circuit according to a preset electrical relationship model of each component formed according to the system topology, or calculate the RF output impedance of the RF generator and the current impedance of each variable impedance element.

[0054] In one embodiment, the fractional-order controller 200 includes an error calculation unit 210, a fractional-order PID control unit 220, and an instruction generation unit 230;

[0055] The error calculation unit 210 is connected to the sensor module 100 and is used to receive the RF output impedance Z detected by the sensor module 100. out and the current impedance Z of the variable impedance circuit, and the RF output impedance is used as the matching network input impedance Z in , bring into the functional relationship between the preset variable impedance circuit impedance and the matching network input impedance, obtain the target impedance Z' of the variable impedance circuit during impedance matching, and obtain the current error impedance ΔZ of the variable impedance circuit according to the difference between the target impedance Z' of the variable impedance circuit and the current impedance Z of the variable impedance circuit;

[0056] The fractional-order PID control unit 220 is connected to the error calculation unit 210 and is used to bring the current error impedance ΔZ of the variable impedance circuit into the fractional-order PID control algorithm to obtain the impedance adjustment amount ΔZ' of the variable impedance circuit;

[0057] The instruction generation unit 230 is connected to the fractional-order PID control unit 220 and the driving module 300 respectively, and is used to generate an adjustment instruction according to the impedance adjustment amount ΔZ′ and send the instruction to the driving module 300 .

[0058] Specifically, the preset functional relationship between the variable impedance circuit impedance and the matching network input impedance is the functional relationship between the variable impedance circuit impedance and the matching network input impedance obtained by modeling the topology structure of the device before the device works. In the present device, the target impedance of the variable impedance circuit is determined according to the preset functional relationship between the variable impedance circuit impedance and the matching network input impedance, and the algorithm complexity is low and the operation speed is fast.

[0059] In one embodiment, the variable impedance circuit 400 is composed of a plurality of variable impedance elements, and the sensor module 100 detects and obtains the RF output impedance Z out , and simultaneously detect the current impedance of each variable impedance element, and calculate the current impedance Z of the entire variable impedance circuit according to the topological structure model of the variable impedance circuit.

[0060] The functional relationship between the variable impedance circuit impedance and the matching network input impedance is:

[0061] Z in =f(Z)

[0062] Z out As Z in Substitute it into it and get the target impedance Z' of the variable impedance circuit during impedance matching;

[0063] The current error impedance ΔZ of the variable impedance circuit is obtained according to the following formula.

[0064] ΔZ=|Z-Z'|

[0065] ΔZ is then input into the fractional-order PID control algorithm to obtain the impedance adjustment amount ΔZ' of the variable impedance circuit. Since the variable impedance circuit in this embodiment includes multiple variable impedance elements, the instruction generation unit 230 is also used to obtain the impedance adjustment amount of each variable impedance element according to the topological structure model of each variable impedance circuit, generate an adjustment instruction according to the impedance adjustment amount of each variable impedance element, and control the driving module 300 to adjust the current impedance of each variable impedance element.

[0066] In one embodiment, variable impedance circuit 300 includes a first variable impedance element and a second variable impedance element.

[0067] The sensor module 100 is used to detect the RF output impedance Z of the RF generating device. out , the current impedance Z1 of the first variable impedance element, and the current impedance Z2 of the second variable impedance element are transmitted to the error calculation unit 210.

[0068] The error calculation unit 210 is connected to the sensor module 100 and is used to receive the RF output impedance Z detected by the sensor module. out , the current impedance Z1 of the first variable impedance element and the current impedance Z2 of the second variable impedance element, and the RF output impedance Z out As the matching network input impedance Z in , the impedance Z1 of the first variable impedance element, the impedance Z2 of the second variable impedance element and the input impedance Z of the matching network are input. in The functional relationship of

[0069] Z in =f(Z1,Z2)

[0070] The target impedance Z'1 of the first variable impedance element and the target impedance Z'2 of the second variable impedance element during impedance matching are obtained, and the current error impedance ΔZ1 of the first variable impedance element is obtained according to the difference Z1 between the target impedance Z'1 of the first variable impedance element and the current impedance of the first variable impedance element, and the current error impedance ΔZ2 of the second variable impedance element is obtained according to the difference between the target impedance Z'2 of the second variable impedance element and the current impedance Z2 of the second variable impedance element.

[0071] Optionally, the current error impedance ΔZ1 of the first variable impedance element and the current error impedance ΔZ2 of the second variable impedance element are obtained according to the formula: ΔZ1=|Z1-Z'1|, ΔZ2=|Z2-Z'2|.

[0072] The fractional-order PID control unit 220 is connected to the error calculation unit 210, and is used to respectively bring the current error impedance ΔZ1 of the first variable impedance element and the current error impedance ΔZ2 of the second variable impedance element into the fractional-order PID control algorithm to obtain the impedance adjustment amount ΔZ'1 of the first variable impedance element and the impedance adjustment amount ΔZ'2 of the second variable impedance element.

[0073] The instruction generation unit 230 is connected to the fractional-order PID control unit 220 and the driving module 300, respectively, and is used to generate an adjustment instruction according to the impedance adjustment amount ΔZ'1 of the first variable impedance element and the impedance adjustment amount ΔZ'2 of the second variable impedance element and send it to the driving module;

[0074] The driving module 300 is used to adjust the current impedance Z1 of the first variable impedance element and the current impedance Z2 of the second variable impedance element according to the adjustment instruction, so that the RF output impedance matches the input impedance of the matching network.

[0075] In one embodiment, the first variable impedance element is a variable capacitor or a variable electron.

[0076] In one embodiment, the second variable impedance element is a variable capacitor or a variable electron.

[0077] In one embodiment, two fractional-order PID control algorithm models are set in the fractional-order PID control unit, which are used to control the error of the first variable impedance element and the error of the second variable impedance element respectively. The current error impedance ΔZ1 of the first variable impedance element and the current error impedance ΔZ2 of the second variable impedance element are respectively brought into the fractional-order PID control algorithm to obtain the impedance adjustment amount ΔZ'1 of the first variable impedance element and the impedance adjustment amount ΔZ'2 of the second variable impedance element, including:

[0078] Substituting the current error impedance ΔZ1 of the first variable impedance element into the first fractional-order PID control algorithm to obtain the impedance adjustment amount ΔZ'1 of the first variable impedance element;

[0079] The current error impedance ΔZ2 of the second variable impedance element is brought into the second fractional-order PID control algorithm to obtain the impedance adjustment amount ΔZ′2 of the second variable impedance element.

[0080] The embodiment of the present application also provides a radio frequency impedance matching method, which is applied to any of the above-mentioned fractional-order controllers 200, including:

[0081] Step S520, receiving the radio frequency output impedance of the radio frequency generating device and the current impedance of the variable impedance circuit sent by the sensor module 100;

[0082] Step S530, obtaining a current error impedance of the variable impedance circuit according to the RF output impedance and the variable impedance circuit; the current error impedance is obtained according to the difference between the target impedance of the variable impedance circuit during impedance matching and the current impedance of the variable impedance circuit;

[0083] Step S540, according to the current error impedance of the variable impedance circuit, based on the fractional-order PID control algorithm, obtain the impedance adjustment amount of the variable impedance circuit;

[0084] Step S550, generating an adjustment instruction according to the impedance adjustment amount and sending it to the driving module 300; the adjustment instruction is used to control the driving module 300 to adjust the impedance of the variable impedance circuit according to the impedance adjustment amount so that the RF output impedance matches the matching network input impedance.

[0085] For the specific definition of the RF impedance matching method, please refer to the definition of the RF impedance matching device above, which will not be repeated here.

[0086] In one embodiment, the step of obtaining the current error impedance of the variable impedance circuit according to the RF output impedance and the variable impedance circuit includes:

[0087] Step S531, taking the RF output impedance as the matching network input impedance, and substituting it into a preset functional relationship between the variable impedance circuit impedance and the matching network input impedance, to obtain the target impedance of the variable impedance circuit when impedance matching is performed;

[0088] Step S532: obtaining a current error impedance of the variable impedance circuit according to a difference between the target impedance of the variable impedance circuit and the current impedance of the variable impedance circuit.

[0089] In one embodiment, the variable impedance circuit includes at least one variable impedance element, and before the step of receiving the RF output impedance of the RF generating device and the current impedance of the variable impedance circuit sent by the sensor module 100, it also includes:

[0090] Step S510 , according to the topological relationship of each variable impedance element, a functional relationship between the input impedance of the matching network and the impedance of each variable impedance element is obtained through modeling.

[0091] In one embodiment, the integral term fractional order factor of the fractional order PID control algorithm is greater than zero, and the differential term fractional order factor is less than two.

[0092] In one embodiment, a radio frequency impedance matching method is provided, which is applied to the fractional-order controller 200 of the radio frequency impedance matching device mentioned above, wherein the variable impedance circuit in the radio frequency impedance matching device includes a first variable impedance element and a second variable impedance element.

[0093] receiving the RF output impedance detected by the sensor module 100 , the current impedance of the first variable impedance element, and the current impedance of the second variable impedance element;

[0094] The RF output impedance is used as the input impedance of the matching network, and the preset impedance of the first variable impedance element, the impedance of the second variable impedance element and the functional relationship of the input impedance of the matching network are substituted into the functional relationship, so as to obtain the target impedance of the first variable impedance element and the target impedance of the second variable impedance element when the impedance is matched;

[0095] Obtaining a current error impedance of the first variable impedance element according to a difference between a target impedance of the first variable impedance element and a current impedance of the first variable impedance element;

[0096] Obtaining a current error impedance of the second variable impedance element according to a difference between a target impedance of the second variable impedance element and a current impedance of the second variable impedance element;

[0097] Substituting the current error impedance of the first variable impedance element into the first fractional-order PID control algorithm to obtain the impedance adjustment amount of the first variable impedance element;

[0098] Bringing the current error impedance of the second variable impedance element into the second fractional-order PID control algorithm to obtain the impedance adjustment amount of the second variable impedance element;

[0099] An adjustment instruction is generated according to the impedance adjustment amount of the first variable impedance element and the impedance adjustment amount of the second variable impedance element and sent to the driving module; the adjustment instruction is used to control the driving module to adjust the current impedance of the first variable impedance element and the current impedance of the second variable impedance element so that the RF output impedance matches the matching network input impedance.

[0100] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0101] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A radio frequency impedance matching device, characterized in that: include: A sensor module, a fractional-order controller, a driving module, and a variable impedance circuit; The variable impedance circuit is used to connect the RF generator and the plasma chamber respectively, and the sensor module is used to detect the RF output impedance of the RF generator and the current impedance of the variable impedance circuit, and transmit them to the fractional-order controller; the sensor module is arranged on the RF transmission line between the RF generator and the variable impedance circuit, or connected to the output end of the RF generator through a first detection end, and connected to the variable impedance circuit through a second detection end; the sensor module outputs the detection result according to the set detection cycle; The fractional-order controller is connected to the sensor module and the driving module respectively, and is used to obtain the current error impedance of the variable impedance circuit according to the RF output impedance and the current impedance of the variable impedance circuit, and obtain the impedance adjustment amount of the variable impedance circuit based on the fractional-order PID control algorithm, and generate an adjustment instruction according to the impedance adjustment amount and send it to the driving module; the current error impedance is obtained according to the difference between the target impedance of the variable impedance circuit and the current impedance of the variable impedance circuit during impedance matching; The driving module is used to adjust the current impedance of the variable impedance circuit according to the adjustment instruction so that the RF output impedance matches the matching network input impedance.

2. The radio frequency impedance matching device according to claim 1, characterized in that: The fractional-order controller comprises an error calculation unit, a fractional-order PID control unit and an instruction generation unit; The error calculation unit is connected to the sensor module, and is used to receive the RF output impedance detected by the sensor module and the current impedance of the variable impedance circuit, and use the RF output impedance as the matching network input impedance, and bring it into a preset functional relationship between the variable impedance circuit impedance and the matching network input impedance to obtain the target impedance of the variable impedance circuit when impedance matching occurs, and obtain the current error impedance of the variable impedance circuit according to the difference between the target impedance of the variable impedance circuit and the current impedance of the variable impedance circuit; The fractional-order PID control unit is connected to the error calculation unit and is used to bring the current error impedance of the variable impedance circuit into the fractional-order PID control algorithm to obtain the impedance adjustment amount of the variable impedance circuit; The instruction generating unit is connected to the fractional-order PID control unit and the driving module respectively, and is used for generating an adjustment instruction according to the impedance adjustment amount and sending the adjustment instruction to the driving module.

3. The radio frequency impedance matching device according to claim 2, characterized in that: The variable impedance circuit includes at least one variable impedance element.

4. The radio frequency impedance matching device according to claim 3, characterized in that: The variable impedance circuit includes a first variable impedance element and a second variable impedance element; The sensor module is used to detect the RF output impedance of the RF generating device, the current impedance of the first variable impedance element and the current impedance of the second variable impedance element, and transmit them to the error calculation unit; The error calculation unit is connected to the sensor module, and is used to receive the RF output impedance, the current impedance of the first variable impedance element, and the current impedance of the second variable impedance element detected by the sensor module, and use the RF output impedance as the matching network input impedance, and bring into the preset functional relationship between the impedance of the first variable impedance element, the impedance of the second variable impedance element, and the input impedance of the matching network to obtain the target impedance of the first variable impedance element and the target impedance of the second variable impedance element during impedance matching, and obtain the current error impedance of the first variable impedance element according to the difference between the target impedance of the first variable impedance element and the current impedance of the first variable impedance element, and obtain the current error impedance of the second variable impedance element according to the difference between the target impedance of the second variable impedance element and the current impedance of the second variable impedance element; The fractional-order PID control unit is connected to the error calculation unit, and is used to bring the current error impedance of the first variable impedance element and the current error impedance of the second variable impedance element into the fractional-order PID control algorithm respectively, to obtain the impedance adjustment amount of the first variable impedance element and the impedance adjustment amount of the second variable impedance element; The instruction generating unit is connected to the fractional-order PID control unit and the driving module respectively, and is used to generate an adjustment instruction according to the impedance adjustment amount of the first variable impedance element and the impedance adjustment amount of the second variable impedance element and send the adjustment instruction to the driving module; The driving module is used to adjust the current impedance of the first variable impedance element and the current impedance of the second variable impedance element according to the adjustment instruction, so that the RF output impedance matches the input impedance of the matching network.

5. The radio frequency impedance matching device according to claim 4, characterized in that: The integral term fractional order factor of the fractional order PID control algorithm is greater than zero, and the differential term fractional order factor is less than two.

6. The radio frequency impedance matching device according to claim 5, characterized in that: The first variable impedance element is a variable inductor or a variable capacitor.

7. A radio frequency impedance matching method, applied to the fractional-order controller according to claim 1, characterized in that: include: receiving the radio frequency output impedance of the radio frequency generating device and the current impedance of the variable impedance circuit sent by the sensor module; According to the RF output impedance and the variable impedance circuit, a current error impedance of the variable impedance circuit is obtained; the current error impedance is obtained according to the difference between the target impedance of the variable impedance circuit and the current impedance of the variable impedance circuit during impedance matching; According to the current error impedance of the variable impedance circuit, based on a fractional-order PID control algorithm, an impedance adjustment amount of the variable impedance circuit is obtained; An adjustment instruction is generated according to the impedance adjustment amount and sent to the driving module; the adjustment instruction is used to control the driving module to adjust the impedance of the variable impedance circuit according to the impedance adjustment amount so that the RF output impedance matches the matching network input impedance.

8. The radio frequency impedance matching method according to claim 7, characterized in that: The step of obtaining the current error impedance of the variable impedance circuit according to the RF output impedance and the variable impedance circuit comprises: The RF output impedance is used as the matching network input impedance, and is substituted into a functional relationship between a preset variable impedance circuit impedance and the matching network input impedance to obtain a target impedance of the variable impedance circuit when impedance matching is performed; A current error impedance of the variable impedance circuit is obtained according to a difference between a target impedance of the variable impedance circuit and a current impedance of the variable impedance circuit.

9. The radio frequency impedance matching method according to claim 8, characterized in that: The variable impedance circuit includes at least one variable impedance element, and before the step of receiving the RF output impedance of the RF generating device and the current impedance of the variable impedance circuit sent by the sensor module, it also includes: According to the topological relationship of each of the variable impedance elements, a functional relationship between the input impedance of the matching network and the impedance of each of the variable impedance elements is obtained through modeling.

10. The radio frequency impedance matching method according to claim 8 or 9, characterized in that: The integral term fractional order factor of the fractional order PID control algorithm is greater than zero, and the differential term fractional order factor is less than two.

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