Impedance matcher and impedance matching method

Abstract

The invention provides an impedance matcher and an impedance matching method, the impedance matcher comprises a matching circuit and a control module, the matching circuit comprises at least one matching inductor and a plurality of variable matching capacitors, the matching circuit is connected with a matching load, and the control module obtains a plurality of groups of matching inductance values; based on any group of matching inductance values, the first target impedance, an impedance detection value before each time of iterative matching and capacitance values of a plurality of variable matching capacitors before iterative matching, multiple times of iterative matching are carried out to obtain matching data corresponding to the matching inductance values, and the impedance detection value is the sum of the actual impedance of the matching circuit and the impedance of the matching load; and the control module selects an effective matching inductance value from the multiple groups of matching inductance values based on the multiple groups of matching inductance values and the iteration matching data corresponding to the multiple groups of matching inductance values, and determines the target capacitance value of each variable matching capacitor based on the effective matching inductance value and the second target impedance. According to the invention, the convergence speed of the matching network model can be improved, and the impedance matching accuracy is high.

Description

Technical Field

[0001] The present application relates to the field of radio frequency plasma, and in particular to an impedance matcher and an impedance matching method. Background Art

[0002] In the process of exciting plasma by radio frequency (RF) source, radio frequency energy is provided to the plasma chamber by the RF source to ionize the process gas in the high vacuum state, thereby generating a plasma containing a large number of active particles such as electrons, ions, excited atoms, molecules and free radicals. These active particles interact with the wafer placed in the chamber and exposed to the plasma environment, causing various physical and chemical reactions on the surface of the wafer material, thereby changing the surface properties of the material, and completing the etching, deposition or other process of the wafer. In order to achieve the maximum power of the plasma chamber from the RF source, an automatic impedance matcher can be added between the RF source and the plasma chamber to achieve impedance matching between the RF source and the load. In the existing impedance matching method, the matching network model parameters are determined by directly measuring the parameters of the device in the matching circuit. However, due to the influence of parasitic factors, the matching network model parameters obtained by direct measurement are often not accurate enough, the matching network model converges slowly or even cannot converge, and the automatic impedance matching effect is poor. Summary of the invention

[0003] The embodiments of the present application provide an impedance matcher and an impedance matching method, which can improve the convergence speed of the matching network model and have high impedance matching accuracy.

[0004] In the first aspect, the present application provides an impedance matcher, which includes a matching circuit and a control module, wherein the matching circuit includes at least one matching inductor and a plurality of variable matching capacitors, and the matching circuit is connected to a matching load. The control module is used to obtain multiple groups of matching inductance values, and perform multiple iterative matching based on any group of matching inductance values, a first target impedance, an impedance detection value before each iterative matching, and a capacitance value of multiple variable matching capacitors before each iterative matching, to obtain matching data corresponding to any group of matching inductance values, wherein the matching data includes an impedance detection value after each iterative matching and a capacitance value of multiple variable matching capacitors after each iterative matching, and the impedance detection value is the sum of the actual impedance of the matching circuit and the impedance of the matching load. The control module is used to select an effective matching inductance value from multiple groups of matching inductance values ​​based on multiple groups of matching inductance values ​​and iterative matching data corresponding to each group of matching inductance values, and determine the target capacitance value of multiple variable matching capacitors based on the effective matching inductance value and the second target impedance.

[0005] In the present application, the control module in the impedance matcher can obtain multiple groups of matching inductance values, where the control module can obtain multiple groups of matching inductance values ​​based on the measured inductance value of at least one inductor. The control module can perform multiple iterative matching based on any group of matching inductance values, the first target impedance (which can be the impedance of the RF power supply, or the impedance of other test loads), the impedance detection value before each iterative matching, and the capacitance values ​​of multiple variable capacitors before each iterative matching to obtain matching data corresponding to any group of matching inductance values, where the matching data corresponding to any group of matching inductance values ​​can include the capacitance values ​​of multiple variable capacitors after each iterative matching and the impedance detection value after each iterative matching. The control module can select the optimal matching inductance value (or effective matching inductance value) from the above-mentioned multiple groups of matching inductance values ​​based on the iterative matching data corresponding to each group of matching inductance values. The effective matching inductance value can be used as one of the above-mentioned matching network model parameters. The control module combines the matching network model including the effective matching inductance value to perform impedance matching (which can be the matching of the impedance of the plasma chamber plus the impedance matcher with the second target impedance), and adjusts the capacitance value of each variable capacitor based on the target capacitance value of multiple variable matching capacitors obtained by the matching network model. The matching network model converges faster, that is, the control module can match the impedance of the plasma chamber plus the impedance matcher with the impedance of the RF power supply more quickly, and the impedance matching effect is good.

[0006] In combination with the first aspect, in a first possible implementation, the control module is used to select an effective matching inductance value from multiple groups of matching inductance values ​​based on multiple groups of matching inductance values ​​and iterative matching data corresponding to each group of matching inductance values, including the control module obtaining the impedance real part value and the impedance imaginary part value of the matching load after each iterative matching based on any group of matching inductance values ​​and the matching data corresponding to any group of matching inductance values, so as to obtain multiple impedance real part values ​​and multiple impedance imaginary part values ​​of the matching load corresponding to any group of matching inductance values. The control module obtains the variance of multiple impedance real part values ​​and the variance of multiple impedance imaginary part values, or obtains the standard deviation of multiple impedance real part values ​​and the standard deviation of multiple impedance imaginary part values, or obtains the range of multiple impedance real part values ​​and the range of multiple impedance imaginary part values. The control module selects effective matching inductance values ​​from multiple groups of matching inductance values ​​based on the sum of the variances of multiple real impedance values ​​and the variances of multiple imaginary impedance values ​​corresponding to each group of matching inductance values, or the sum of the standard deviations of multiple real impedance values ​​and the standard deviations of multiple imaginary impedance values, or the sum of the ranges of multiple real impedance values ​​and the ranges of multiple imaginary impedance values. The matching inductance value with the smallest sum of the variances of multiple real impedance values ​​and the variances of multiple imaginary impedance values, or the sum of the ranges, or the sum of the standard deviations corresponding to each group of matching inductance values ​​can enable the control module to perform impedance matching through the matching network model at the fastest speed (i.e., complete matching within fewer iterations), and the matching result is more accurate.

[0007] In combination with the first possible implementation of the first aspect, in a second possible implementation, the control module performs multiple iterative matching based on any set of matching inductance values, the first target impedance, the impedance detection value before each iterative matching, and the capacitance values ​​of multiple variable matching capacitors before each iterative matching, including the control module performing multiple iterative matching through the impedance matching network model until the reflection coefficient is lower than a preset value. The reflection coefficient is the ratio of the difference between the impedance detection value after each iterative matching and the first target impedance to the sum of the impedance detection value after each iterative matching and the first target impedance.

[0008] In combination with the second possible implementation of the first aspect, in a third possible implementation, the control module performs multiple iterative matching through an impedance matching network model, including a control module for inputting any group of matching inductance values, a first target impedance, an impedance detection value before each iterative matching, and a capacitance value of multiple variable matching capacitors before each iterative matching into the impedance matching network model, so as to obtain target capacitance values ​​of multiple variable matching capacitors through the impedance matching network model, and adjust the capacitance values ​​of multiple variable matching capacitors based on the target capacitance values ​​of multiple variable matching capacitors. The control module can select an effective matching inductance value from the above-mentioned multiple groups of matching inductance values ​​based on the iterative matching data corresponding to each group of matching inductance values, and the effective matching inductance value can be used as one of the above-mentioned matching network model parameters. The operation unit obtains the target capacitance value of each variable capacitor in combination with the matching network model containing the effective matching inductance value, and the matching network model converges faster.

[0009] In combination with any possible implementation of the first aspect to the third possible implementation of the first aspect, in a fourth possible implementation, the matching circuit includes a first variable matching capacitor and a second variable matching capacitor, and one end of the first variable matching capacitor is connected to one end of the second variable matching capacitor. The other end of the first variable matching capacitor is connected to one end of the matching load through the first matching inductor, and / or the other end of the second variable matching capacitor is connected to the other end of the matching load through the second matching inductor. The control module can select an effective matching inductance value from the above-mentioned multiple groups of matching inductance values ​​based on the iterative matching data corresponding to each group of matching inductance values. The effective matching inductance value can be used as one of the matching network model parameters. The operation unit obtains the target capacitance value of each variable capacitor in combination with the matching network model containing the effective matching inductance value, and the matching network model converges faster.

[0010] In combination with the fourth possible implementation of the first aspect, in a fifth possible implementation, the matching circuit includes a third variable matching capacitor, one end of the third variable matching capacitor is connected to the connection end of the first variable matching capacitor and the second variable matching capacitor, or one end of the third variable matching capacitor is connected to the connection end of the first variable matching capacitor and the second variable matching capacitor through a third matching inductor. The control module can select an effective matching inductance value from the above-mentioned multiple groups of matching inductance values ​​based on the iterative matching data corresponding to each group of matching inductance values, and the effective matching inductance value can be used as one of the matching network model parameters. The operation unit obtains the target capacitance value of each variable capacitor in combination with the matching network model containing the effective matching inductance value, and the matching network model converges faster.

[0011] In combination with any possible implementation of the first aspect to the third possible implementation of the first aspect, in a sixth possible implementation, the matching circuit includes a first variable matching capacitor and a second variable matching capacitor, one end of the first variable matching capacitor is connected to one end of the second variable matching capacitor through a first matching inductor, and the connection end of the second variable matching capacitor and the matching inductor is connected to one end of the matching load. The other end of the first variable matching capacitor is connected to the other end of the matching load through the second matching inductor, and / or the other end of the second variable matching capacitor is connected to the other end of the matching load through the third matching inductor. The control module can select an effective matching inductance value from the above-mentioned multiple groups of matching inductance values ​​based on the iterative matching data corresponding to each group of matching inductance values, and the effective matching inductance value can be used as one of the above-mentioned matching network model parameters. The operation unit obtains the target capacitance value of each variable capacitor in combination with the matching network model containing the effective matching inductance value, and the matching network model converges faster.

[0012] In a second aspect, the present application provides an impedance matching method, wherein the impedance matching device applicable to the method includes a matching circuit, the matching circuit includes at least one matching inductor and multiple variable matching capacitors, the matching circuit is connected to a matching load, and the method includes obtaining multiple groups of matching inductance values, and performing multiple iterative matching based on any group of matching inductance values, a first target impedance, an impedance detection value before each iterative matching, and a capacitance value of multiple variable matching capacitors before each iterative matching, to obtain matching data corresponding to any group of matching inductance values, wherein the matching data includes an impedance detection value after each iterative matching and a capacitance value of multiple variable matching capacitors after each iterative matching, and the impedance detection value is the sum of the actual impedance of the matching circuit and the impedance of the matching load. Based on multiple groups of matching inductance values ​​and iterative matching data corresponding to each group of matching inductance values, an effective matching inductance value is selected from multiple groups of matching inductance values, and the target capacitance values ​​of multiple variable matching capacitors are determined based on the effective matching inductance value and the second target impedance.

[0013] In the present application, the control module in the impedance matcher can obtain multiple groups of matching inductance values, where the control module can obtain multiple groups of matching inductance values ​​based on the measured inductance value of at least one inductor. The control module can perform multiple iterative matching based on any group of matching inductance values, the first target impedance (which can be the impedance of the RF power supply, or the impedance of other test loads), the impedance detection value before each iterative matching, and the capacitance values ​​of multiple variable capacitors before each iterative matching to obtain matching data corresponding to any group of matching inductance values, where the matching data corresponding to any group of matching inductance values ​​can include the capacitance values ​​of multiple variable capacitors after each iterative matching and the impedance detection value after each iterative matching. The control module can select the optimal matching inductance value (or effective matching inductance value) from the above-mentioned multiple groups of matching inductance values ​​based on the iterative matching data corresponding to each group of matching inductance values. The effective matching inductance value can be used as one of the above-mentioned matching network model parameters. The control module combines the matching network model including the effective matching inductance value to perform impedance matching (which can be the matching of the impedance of the plasma chamber plus the impedance matcher with the second target impedance), and adjusts the capacitance value of each variable capacitor based on the target capacitance value of multiple variable matching capacitors obtained by the matching network model. The matching network model converges faster, that is, the control module can match the impedance of the plasma chamber plus the impedance matcher with the impedance of the RF power supply more quickly, and the impedance matching effect is good.

[0014] In combination with the second aspect, in a first possible implementation, selecting an effective matching inductance value from a plurality of matching inductance values ​​based on a plurality of matching inductance values ​​and iterative matching data corresponding to each matching inductance value group includes obtaining the impedance real part value and the impedance imaginary part value of the matching load after each iterative matching based on any matching inductance value group and the matching data corresponding to any matching inductance value group, so as to obtain a plurality of impedance real part values ​​and a plurality of impedance imaginary part values ​​of the matching load corresponding to any matching inductance value group. Obtain the variance of the plurality of impedance real part values ​​and the variance of the plurality of impedance imaginary part values, or obtain the standard deviation of the plurality of impedance real part values ​​and the standard deviation of the plurality of impedance imaginary part values, or obtain the range of the plurality of impedance real part values ​​and the range of the plurality of impedance imaginary part values. Select an effective matching inductance value from a plurality of matching inductance values ​​based on the sum of the variance of the plurality of impedance real part values ​​and the variance of the plurality of impedance imaginary part values ​​corresponding to each matching inductance value group, or the sum of the standard deviation of the plurality of impedance real part values ​​and the standard deviation of the plurality of impedance imaginary part values, or the sum of the range of the plurality of impedance real part values ​​and the range of the plurality of impedance imaginary part values. The matching inductance value with the smallest sum of the variances of the real part values ​​of the impedances and the variances of the imaginary part values ​​of the impedances corresponding to each group of matching inductance values, or the sum of the ranges, or the sum of the standard deviations, can enable the control module to perform impedance matching through the matching network model at the fastest speed (i.e., complete the matching within fewer iterations) and provide more accurate matching results.

[0015] In combination with the first possible implementation of the second aspect, in a second possible implementation, multiple iterative matching is performed based on any group of matching inductance values, the first target impedance, the actual impedance of the matching circuit before each iterative matching, and the capacitance values ​​of multiple variable matching capacitors before each iterative matching, including multiple iterative matching through an impedance matching network model until the reflection coefficient is lower than a preset value. The reflection coefficient is the difference between the impedance detection value after each iterative matching and the first target impedance, and the ratio of the sum of the impedance detection value after each iterative matching and the first target impedance. The control module can select an effective matching inductance value from the above-mentioned multiple groups of matching inductance values ​​based on the iterative matching data corresponding to each group of matching inductance values. The effective matching inductance value can be used as one of the above-mentioned matching network model parameters. The operation unit combines the matching network model containing the effective matching inductance value to obtain the target capacitance value of each variable capacitor, and the matching network model converges faster.

[0016] In combination with the second possible implementation of the second aspect, in a third possible implementation, performing multiple iterative matching through an impedance matching network model includes inputting any group of matching inductance values, the first target impedance, the impedance detection value before each iterative matching, and the capacitance values ​​of multiple variable matching capacitors before each iterative matching into the impedance matching network model, so as to obtain the target capacitance values ​​of multiple variable matching capacitors through the impedance matching network model, and adjust the capacitance values ​​of multiple variable matching capacitors based on the target capacitance values ​​of multiple variable matching capacitors. The control module can select an effective matching inductance value from the above-mentioned multiple groups of matching inductance values ​​based on the iterative matching data corresponding to each group of matching inductance values, and the effective matching inductance value can be used as one of the above-mentioned matching network model parameters. The operation unit obtains the target capacitance value of each variable capacitor in combination with the matching network model containing the effective matching inductance value, and the matching network model converges faster. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of an impedance matching system;

[0018] Figure 2 A schematic diagram of the structure of an impedance matching system provided in an embodiment of the present application;

[0019] Figure 3 A schematic diagram of the structure of an impedance matching system provided in an embodiment of the present application;

[0020] Figure 4 A schematic diagram of the structure of an impedance matching system provided in an embodiment of the present application;

[0021] Figure 5 A schematic diagram of the structure of an impedance matching system provided in an embodiment of the present application;

[0022] Figure 6A schematic diagram of the structure of an impedance matching system provided in an embodiment of the present application;

[0023] Figure 7 A schematic diagram of the structure of an impedance matching system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0024] See also Figure 1 , Figure 1 It is a structural diagram of an impedance matching system. Figure 1 The impedance matching system in may include a radio frequency power source and a matching load, wherein the matching load may be a plasma chamber. Figure 1 In the impedance matching system shown, the RF power supply can provide RF energy to the plasma chamber to ionize the gas in the vacuum state in the plasma chamber, thereby generating a plasma containing a large number of active particles such as electrons, ions, excited atoms, molecules and free radicals. These active particles interact with the wafer placed in the chamber and exposed to the plasma environment, causing various physical and chemical reactions on the surface of the wafer material, thereby changing the surface properties of the material and completing the etching, deposition or other process of the wafer. Please refer again Figure 1 , an impedance matcher can be added between the RF power supply and the plasma chamber. The control module in the impedance matcher can adjust the tuning element (such as a variable capacitor) in the matching circuit based on the impedance value of the RF power supply combined with the matching network model, so that the impedance of the plasma chamber plus the impedance matcher matches the impedance of the RF power supply to ensure that the plasma chamber obtains the maximum power from the RF source. In the process of impedance matching through an impedance matcher, the accuracy of the matching network model parameters is very important for the impedance matching effect. However, in the existing impedance matching methods, the parameters of the devices in the matching circuit are usually directly measured to determine the matching network model parameters. Due to the influence of parasitic factors, the matching network model parameters obtained by direct measurement are often not accurate enough, the matching network model converges slowly or even cannot converge, and the impedance matching effect is poor.

[0025] Combine the following Figures 2 to 7 The impedance matching system provided by the embodiment of the present application is introduced. In some feasible implementations, the impedance matching device in the impedance matching system may include a matching circuit and a control module, the matching circuit may include at least one matching inductor and a plurality of variable matching capacitors, and the matching circuit may be connected to a matching load. Figure 2 , Figure 2 A schematic diagram of the structure of an impedance matching system provided in an embodiment of the present application. Figure 2In the impedance matching system shown, the impedance matcher may include a matching circuit and a control module. Specifically, the matching circuit may include a matching inductor (for convenience of description, it can be expressed as an inductor L1) and two variable matching capacitors (for convenience of description, it can be expressed as a variable capacitor C1 and a variable capacitor C2), one end of the variable capacitor C1 is connected to one end of the variable capacitor C2, the other end of the variable capacitor C1 is connected to one end of the matching load and one end of the RF power supply through the inductor L1, the other end of the variable capacitor C2 is connected to the other end of the matching load, and the connection end of the variable capacitor C1 and the variable capacitor C2 is connected to the other end of the RF power supply. The control module in the impedance matcher can adjust the capacitance value of the variable capacitor C1 and the variable capacitor C2 in the matching circuit based on the impedance value of the RF power supply in combination with the matching network model, so that the impedance of the matching load (which can be the plasma chamber) plus the impedance of the impedance matcher (which can be the total impedance of the matching circuit) matches the impedance of the RF power supply to ensure that the plasma chamber obtains maximum power from the RF source.

[0026] In some possible implementations, Figure 2In the impedance matching system shown, in the process of impedance matching of the impedance matcher through the matching network model, the matching network model parameters of the matching network model may include the capacitance value of the variable capacitor C1, the capacitance value of the variable capacitor C2, and the inductance value of the inductor L1. The control module can obtain multiple sets of matching inductance values. Here, the control module can obtain multiple sets of matching inductance values ​​based on the measured inductance value of the inductor L1 (which can be multiple sets of matching inductance values ​​whose measured inductance value of the inductor L1 is within a set interval). The control module can perform multiple iterative matching based on any set of matching inductance values, the first target impedance (which can be the impedance of the RF power supply, or the impedance of other test loads), the impedance detection value before each iterative matching (which can be the sum of the actual impedance of the matching circuit before the iterative matching and the impedance of the matching load), and the capacitance values ​​of the variable capacitor C1 and the variable capacitor C2 before each iterative matching to obtain matching data corresponding to any set of matching inductance values. Here, the matching data corresponding to any set of matching inductance values ​​can include the capacitance values ​​of the variable capacitor C1 and the variable capacitor C2 after each iterative matching and the impedance detection value after each iterative matching (which can be the sum of the actual impedance of the matching circuit after the iterative matching and the impedance of the matching load). The control module can select the optimal matching inductance value (or effective matching inductance value) from the above-mentioned multiple groups of matching inductance values ​​based on the iterative matching data corresponding to each group of matching inductance values. The effective matching inductance value can be used as one of the above-mentioned matching network model parameters. The control module combines the matching network model including the effective matching inductance value to perform impedance matching (which can be the matching of the impedance of the plasma chamber plus the impedance matcher with the second target impedance), and adjusts the capacitance value of each variable capacitor based on the target capacitance value of multiple variable matching capacitors obtained by the matching network model. The matching network model converges faster, that is, the control module can match the impedance of the plasma chamber plus the impedance matcher with the impedance of the RF power supply more quickly, and the impedance matching effect is good.

[0027] In some possible implementations, Figure 2 In the impedance matching system shown, the control module can obtain the impedance real part value and the impedance imaginary part value of the matching load after each iterative matching based on any set of matching inductance values ​​and the matching data corresponding to any set of matching inductance values, so as to obtain multiple impedance real part values ​​and multiple impedance imaginary part values ​​of the matching load corresponding to any set of matching inductance values. Specifically, the control module can obtain the impedance real part value and the impedance imaginary part value of the matching load corresponding to any set of matching inductance values ​​based on any set of matching inductance values ​​(for example, the matching inductance value L m ) The corresponding matching data is used to obtain the matching inductance value L m After the nth iteration matching, the capacitance values ​​of the variable capacitor C1 and the variable capacitor C2 (for example, they can be C 1n and C 2n ), and the sum of the actual impedance of the matching circuit obtained after the nth iteration matching and the impedance of the matching load above Z pn(Here, the sum of the impedance of the matching circuit and the above-mentioned matching load can be obtained by voltage and current probe detection after each iterative matching.) Further, the above-mentioned matching inductance value L m , C 1n and C 2n The impedance can be expressed as "jwL m ”, “1 / jwC 1n ” and “1 / jwC 2n ", where w is the RF source frequency (can be 13.56Mhz). According to the total impedance of the series link is the sum of the link impedances, and the total admittance of the parallel link is the sum of the link admittances, the following relationship exists:

[0028]

[0029] Among them, Z ln is the impedance of the matched load after the nth iteration matching. pn , which can be divided into the real part of the impedance R pn and the imaginary part of impedance I pn , that is, Z pn It can be expressed as:

[0030] Z pn =R pn +j*I pn

[0031] The above Z ln It can be divided into the real part of the impedance R ln and the imaginary part of impedance I ln , that is, Z ln It can be expressed as:

[0032] Z ln =R ln +j*I ln

[0033] Combining the above relationships, we can get the equation:

[0034]

[0035] Here, the matching inductance value L can be obtained based on the fact that the real part of the impedance on the left side of the equation is equal to the real part of the impedance on the right side of the equation. m The real part of the impedance of the matched load after the nth iteration matching is I ln According to the equation, the imaginary impedance value on the left side is equal to the imaginary impedance value on the right side, so the matching inductance value L can be obtained. m The imaginary impedance value R of the matched load after the nth iteration matching ln. Further, the control module can obtain the impedance real part value and the impedance imaginary part value of the matching load after each iterative matching based on any one of the multiple groups of matching inductance values ​​and the matching data corresponding to any one of the multiple groups of matching inductance values, so as to obtain multiple impedance real part values ​​and multiple impedance imaginary part values ​​of the matching load corresponding to any one of the multiple groups of matching inductance values, thereby selecting an effective matching inductance value from the multiple groups of matching inductance values ​​based on the multiple impedance real part values ​​and multiple impedance imaginary part values ​​of the matching load corresponding to any one of the multiple groups of matching inductance values. The above-mentioned effective matching inductance value can be used as one of the above-mentioned matching network model parameters. The control module adjusts the capacitance values ​​of the variable capacitor C1 and the variable capacitor C2 in the matching circuit in combination with the matching network model containing the effective matching inductance value. The matching network model converges faster, that is, the control module can match the impedance of the plasma chamber plus the impedance matcher with the impedance of the RF power supply faster, and the impedance matching effect is good.

[0036] In some possible implementations, Figure 2In the impedance matching system shown, the control module can obtain the variances of multiple real impedance values ​​and multiple imaginary impedance values ​​based on multiple real impedance values ​​and multiple imaginary impedance values ​​of the matching load corresponding to any group of matching inductance values, thereby selecting effective matching inductance values ​​from multiple groups of matching inductance values ​​based on the sum of the variances of multiple real impedance values ​​and multiple imaginary impedance values ​​corresponding to each group of matching inductance values. Specifically, the control module can obtain multiple groups of matching inductance values ​​based on the measured inductance value of the inductor L1. For example, the measured inductance value of the inductor L1 is 520nH. Based on the measured inductance value, multiple groups of matching inductance values ​​are obtained within a set interval, which can be multiple groups of matching inductance values ​​ranging from 450nH to 750nH. The control module can obtain a plurality of impedance real part values ​​and a plurality of impedance imaginary part values ​​of the matching load corresponding to any set of matching inductance values ​​from 450nH to 750nH to obtain the variance of the plurality of impedance real part values ​​and the variance of the plurality of impedance imaginary part values, thereby selecting the matching inductance value with the minimum variance and the minimum variance from 450nH to 750nH as the effective matching inductance value based on the sum of the variance of the plurality of impedance real part values ​​and the variance of the plurality of impedance imaginary part values ​​corresponding to each set of matching inductance values. Here, since the resistance value of the load impedance connected to the impedance matcher is fixed, the impedance real part value and the impedance imaginary part value of the matching load after multiple iterative matching obtained based on the above equation should remain stable. In the process of impedance matching through the matching network model, the control module selects some matching inductance values ​​as one of the matching network model parameters of the matching network model for impedance matching. The real impedance value and the imaginary impedance value of the matching load after multiple iterative matching obtained based on the above equation fluctuate greatly (the degree of fluctuation can be determined by the variance of the above multiple real impedance values ​​and the variance of the multiple imaginary impedance values), that is, the selected matching inductance value is not accurate enough, resulting in a slow convergence speed of the matching network model. In other words, the matching inductance value with the smallest sum of the variances of the multiple real impedance values ​​and the multiple imaginary impedance values ​​corresponding to each group of matching inductance values ​​can make the control module perform impedance matching through the matching network model at the fastest speed (that is, complete matching in fewer iterations), and the matching result is more accurate. In addition, the control module can obtain multiple impedance real part values ​​and multiple impedance imaginary part values ​​of the matching load corresponding to any group of matching inductance values ​​from 450nH to 750nH to obtain multiple standard deviations or ranges of the impedance real part values, as well as the standard deviations or ranges of the multiple impedance imaginary part values, thereby selecting the matching inductance value with the smallest sum of standard deviations from 450nH to 750nH as the effective matching inductance value based on the sum of the standard deviations of the multiple impedance real part values ​​and the standard deviations of the multiple impedance imaginary part values ​​corresponding to each group of matching inductance values, or selecting the matching inductance value with the smallest sum of ranges from 450nH to 750nH as the effective matching inductance value based on the sum of the ranges of the multiple impedance real part values ​​and the ranges of the multiple impedance imaginary part values ​​corresponding to each group of matching inductance values.

[0037] In some possible implementations, Figure 2 In the impedance matching system shown, the control module performs multiple iterative matching based on any set of matching inductance values, the first target impedance, the impedance detection value before each iterative matching, and the capacitance values ​​of multiple variable matching capacitors before each iterative matching. During each iterative matching process, the control module can input any set of matching inductance values, the first target impedance, the impedance detection value before each iterative matching, and the capacitance values ​​of the variable capacitors C1 and C2 for each iterative matching into the impedance matching network model to obtain the target capacitance values ​​of the variable capacitors C1 and C2 through the impedance matching network model, and adjust the capacitance values ​​of the variable capacitors C1 and C2 based on the target capacitance values ​​of the variable capacitors C1 and C2 until the iterative matching is terminated when the reflection coefficient is lower than a preset value. Here, the above reflection coefficient can be the sum of the impedance of the matching circuit and the impedance of the above matching load (which can be expressed as Z p ) and the first target impedance (which can be expressed as Z s1 ), and Z p and Z s1 The ratio of the sum of the reflection coefficient can be expressed as (Z p -Z s1 ) / (Z p +Z s1 ).

[0038] In some possible implementations, see Figure 3 , Figure 3 Another structural schematic diagram of the impedance matching system provided in an embodiment of the present application. Figure 3 In the impedance matching system shown in FIG. 1 , the impedance matcher may include a matching circuit and a control module ( Figure 3(not shown). Specifically, the matching circuit may include two matching inductors, namely inductor L1 and inductor L2, and the matching circuit also includes variable capacitor C1 and variable capacitor C2, one end of variable capacitor C1 is connected to one end of variable capacitor C2, the other end of variable capacitor C1 is connected to one end of matching load and one end of RF power supply through inductor L1, the other end of variable capacitor C2 is connected to the other end of matching load through inductor L2, and the connection end of variable capacitor C1 and variable capacitor C2 is connected to the other end of RF power supply. The control module in the impedance matcher can adjust the capacitance value of variable capacitor C1 and variable capacitor C2 in the matching circuit based on the impedance value of RF power supply in combination with the matching network model, so that the impedance of the matching load (which can be the plasma chamber) plus the impedance of the impedance matcher (which can be the total impedance of the matching circuit) matches the impedance of the RF power supply to ensure that the plasma chamber obtains maximum power from the RF source. Specifically, the control module can obtain multiple groups of matching inductance values. Here, the control module can obtain multiple groups of matching inductance values ​​based on the measured inductance values ​​of the inductance L1 and the inductance L2 (each group of matching inductance values ​​includes the matching inductance values ​​of the inductance L1 and the inductance L2, which can be multiple groups of matching inductance values ​​whose measured inductance values ​​of the inductance L1 and the inductance L2 are within a set interval). The control module can perform multiple iterative matching based on any group of matching inductance values, the first target impedance (which can be the impedance of the RF power supply, or the impedance of other test loads), the impedance detection value before each iterative matching, and the capacitance value of the variable capacitor C1 and the variable capacitor C2 before each iterative matching to obtain matching data corresponding to any group of matching inductance values. Here, the matching data corresponding to any group of matching inductance values ​​can include the capacitance values ​​of the variable capacitor C1 and the variable capacitor C2 after each iterative matching and the impedance detection value after each iterative matching. The control module can select a group of effective matching inductance values ​​(which may include effective matching inductance values ​​of inductance L1 and inductance L2) from the above-mentioned multiple groups of matching inductance values ​​based on the iterative matching data corresponding to each group of matching inductance values. The effective matching inductance value can be used as one of the above-mentioned matching network model parameters. The control module adjusts the capacitance values ​​of the variable capacitors C1 and C2 in the matching circuit in combination with the matching network model including the effective matching inductance value. The matching network model converges faster, that is, the control module can match the impedance of the plasma chamber plus the impedance matcher with the impedance of the RF power supply more quickly, and the impedance matching effect is good.

[0039] In some possible implementations, Figure 3 In the impedance matching system shown in FIG. 1 , the matching circuit may further include an inductor L3 and a variable capacitor C3. Please refer to FIG. Figure 4 , Figure 4 Another structural schematic diagram of the impedance matching system provided in an embodiment of the present application. Figure 4 In the impedance matching system shown in FIG. 1 , the impedance matcher may include a matching circuit and a control module ( Figure 4(not shown). Specifically, the matching circuit may include three matching inductors, namely inductor L1, inductor L2 and inductor L3, and the matching circuit also includes variable capacitor C1, variable capacitor C2 and variable capacitor C3, one end of the variable capacitor C1 is connected to one end of the RF power supply through inductor L3 and variable capacitor C3 in turn, one end of the variable capacitor C1 is also connected to one end of the matching load through variable capacitor C2 and inductor L2 in turn, and the other end of the variable capacitor C1 is connected to the other end of the RF power supply and the other end of the load through inductor L1. The control module in the impedance matcher can adjust the capacitance values ​​of the variable capacitor C1, variable capacitor C2 and variable capacitor C3 in the matching circuit based on the impedance value of the RF power supply in combination with the matching network model, so that the impedance of the matching load plus the impedance matcher matches the impedance of the RF power supply to ensure that the plasma chamber obtains maximum power from the RF source.

[0040] In some possible implementations, see Figure 5 , Figure 5 Another structural schematic diagram of the impedance matching system provided in an embodiment of the present application. Figure 5 In the impedance matching system shown in FIG. 1 , the impedance matcher may include a matching circuit and a control module ( Figure 5 (not shown). Specifically, the matching circuit may include a matching inductor, namely, inductor L1, and the matching circuit also includes a variable capacitor C1 and a variable capacitor C2, wherein the variable capacitor C1 is connected in parallel at both ends of the RF power supply, and the variable capacitor C2 is connected in parallel at both ends of the matching load, and one end of the variable capacitor C1 is connected to one end of the variable capacitor C2 through the inductor L1. The control module in the impedance matcher can adjust the capacitance values ​​of the variable capacitors C1 and C2 in the matching circuit based on the impedance value of the RF power supply in combination with the matching network model, so that the impedance of the matching load plus the impedance matcher matches the impedance of the RF power supply to ensure that the plasma chamber obtains maximum power from the RF source.

[0041] In some possible implementations, Figure 5 In the impedance matching system shown, the other end of the variable capacitor C1 can be connected to one end of the RF power supply through the inductor L2, or the other end of the variable capacitor C2 can be connected to one end of the matching load through the inductor L3, or the other ends of the variable capacitor C1 and the variable capacitor C2 are connected to one end of the RF power supply and one end of the matching load through the inductor L2 and the inductor L3 respectively. Please refer to Figure 6 , Figure 6 Another structural diagram of the impedance matching system provided in the embodiment of the present application. Figure 6 As shown, Figure 6 In the impedance matching system shown in FIG. 1 , the impedance matcher may include a matching circuit and a control module ( Figure 6(not shown). Specifically, the matching circuit may include three matching inductors, namely inductor L1, inductor L2 and inductor L3. The matching circuit also includes a variable capacitor C1 and a variable capacitor C2. The variable capacitor C1 is connected in series with the inductor L2 and then connected in parallel at both ends of the RF power supply. The variable capacitor C2 is connected in series with the inductor L3 and then connected in parallel at both ends of the matching load. One end of the variable capacitor C1 is connected to one end of the variable capacitor C2 through the inductor L1. The control module in the impedance matcher can adjust the capacitance values ​​of the variable capacitor C1 and the variable capacitor C2 in the matching circuit based on the impedance value of the RF power supply in combination with the matching network model, so that the impedance of the matching load plus the impedance matcher matches the impedance of the RF power supply to ensure that the plasma chamber obtains maximum power from the RF source. Here, the control module can obtain multiple groups of matching inductance values, and select an effective matching inductance value from the above multiple groups of matching inductance values ​​based on the iterative matching data corresponding to each group of matching inductance values, so as to adjust the variable capacitor in the matching circuit in combination with the matching network model containing the effective matching inductance value. Figures 3 to 5 The control module in the impedance matching system shown in the figure obtains the effective matching inductance value, which can be seen from the above Figure 2 The process of the control module obtaining the effective matching inductance value in the impedance matching system shown is not repeated here.

[0042] In some feasible implementations, the control module in the impedance matcher may include a sensor, a computing unit, and a motor control unit. Specifically, Figure 2 The control module in the impedance matching system shown in the figure includes a sensor, a computing unit and a motor control unit. Figure 7 , Figure 7 Another structural schematic diagram of the impedance matching system provided in an embodiment of the present application. Figure 7In the impedance matching system shown, the impedance matcher may include a matching circuit and a control module. Specifically, the matching circuit may include an inductor L1 and a variable capacitor C1 and a variable capacitor C2, the control module includes a sensor, an operation unit and a motor control unit, the operation unit is connected to the sensor and the motor control unit respectively, one end of the variable capacitor C1 is connected to one end of the variable capacitor C2, the other end of the variable capacitor C1 is connected to one end of the matching load and one end of the RF power supply through the inductor L1, the other end of the variable capacitor C2 is connected to the other end of the matching load, the connection end of the variable capacitor C1 and the variable capacitor C2 is connected to the other end of the RF power supply through the sensor, and the motor control unit is wirelessly connected or electrically connected to the variable capacitor C1 and the variable capacitor C2. The control module performs multiple iterative matching based on any set of matching inductance values, the first target impedance, the impedance detection value before each iteration matching, and the capacitance values ​​of multiple variable matching capacitors before each iteration matching. During each iterative matching process, the control module can obtain the impedance detection value before each iteration matching and the capacitance values ​​of the variable capacitor C1 and the variable capacitor C2 before each iteration matching through the sensor, and input any set of matching inductance values, the first target impedance, the impedance detection value before each iteration matching, and the capacitance values ​​of the variable capacitor C1 and the variable capacitor C2 before each iteration matching into the operation unit, and the operation unit obtains the target capacitance values ​​of the variable capacitor C1 and the variable capacitor C2 through the impedance matching network model, and the motor control unit adjusts the capacitance values ​​of the variable capacitor C1 and the variable capacitor C2 based on the target capacitance values ​​of the variable capacitor C1 and the variable capacitor C2 until the reflection coefficient is lower than the preset value, and the iterative matching is terminated. The above-mentioned operation unit can obtain the matching data corresponding to any set of matching inductance values, and here, the matching data corresponding to any set of matching inductance values ​​can include the capacitance values ​​of the variable capacitor C1 and the variable capacitor C2 after each iteration matching and the impedance detection value after each iteration matching. The control module can select an effective matching inductance value from the above multiple groups of matching inductance values ​​through the operation unit based on the iterative matching data corresponding to each group of matching inductance values. The effective matching inductance value can be used as one of the matching network model parameters. The operation unit combines the matching network model containing the effective matching inductance value to obtain the target capacitance value of the variable capacitor C1 and the variable capacitor C2. The matching network model converges faster, that is, the control module can match the impedance of the plasma chamber plus the impedance matcher with the impedance of the RF power supply faster, and the impedance matching effect is good. It can be understood that the above Figures 3 to 6 The control module in the impedance matching system shown may include a sensor, a computing unit and a motor control unit, and the connection method of each device in the control module is the same as that described above. Figure 7 The impedance matching system shown is similar and will not be described again here.

[0043] In the present application, the control module in the impedance matcher can obtain multiple groups of matching inductance values, where the control module can obtain multiple groups of matching inductance values ​​based on the measured inductance value of at least one inductor. The control module can perform multiple iterative matching based on any group of matching inductance values, the first target impedance (which can be the impedance of the RF power supply, or the impedance of other test loads), the impedance detection value before each iterative matching, and the capacitance values ​​of multiple variable capacitors before each iterative matching to obtain matching data corresponding to any group of matching inductance values, where the matching data corresponding to any group of matching inductance values ​​can include the capacitance values ​​of multiple variable capacitors after each iterative matching and the impedance detection value after each iterative matching. The control module can select the optimal matching inductance value (or effective matching inductance value) from the above-mentioned multiple groups of matching inductance values ​​based on the iterative matching data corresponding to each group of matching inductance values. The effective matching inductance value can be used as one of the above-mentioned matching network model parameters. The control module combines the matching network model including the effective matching inductance value to perform impedance matching (which can be the matching of the impedance of the plasma chamber plus the impedance matcher with the second target impedance), and adjusts the capacitance value of each variable capacitor based on the target capacitance value of multiple variable matching capacitors obtained by the matching network model. The matching network model converges faster, that is, the control module can match the impedance of the plasma chamber plus the impedance matcher with the impedance of the RF power supply more quickly, and the impedance matching effect is good.

Claims

1. An impedance matching device, characterized in that: The impedance matcher includes a matching circuit and a control module, the matching circuit includes at least one matching inductor and a plurality of variable matching capacitors, and the matching circuit is connected to a matching load; The control module is used to obtain multiple groups of matching inductance values, and perform multiple iterative matching based on any group of matching inductance values, the first target impedance, the impedance detection value before each iterative matching, and the capacitance values ​​of the multiple variable matching capacitors before each iterative matching, to obtain matching data corresponding to any group of matching inductance values, wherein the matching data includes the impedance detection value after each iterative matching and the capacitance values ​​of the multiple variable matching capacitors after each iterative matching, and the impedance detection value is the sum of the actual impedance of the matching circuit and the impedance of the matching load; The control module is used to select an effective matching inductance value from the multiple groups of matching inductance values ​​based on the multiple groups of matching inductance values ​​and iterative matching data corresponding to each group of matching inductance values, and determine a target capacitance value of the multiple variable matching capacitors based on the effective matching inductance value and a second target impedance.

2. The impedance matching box according to claim 1, characterized in that: The control module is used to select an effective matching inductance value from the multiple groups of matching inductance values ​​based on the multiple groups of matching inductance values ​​and iterative matching data corresponding to each group of matching inductance values, including: The control module obtains the impedance real part value and the impedance imaginary part value of the matching load after each iterative matching based on any one group of matching inductance values ​​and the matching data corresponding to any one group of matching inductance values, so as to obtain multiple impedance real part values ​​and multiple impedance imaginary part values ​​of the matching load corresponding to any one group of matching inductance values; The control module obtains the variance of the multiple real impedance values ​​and the variance of the multiple imaginary impedance values, or obtains the standard deviation of the multiple real impedance values ​​and the standard deviation of the multiple imaginary impedance values, or obtains the range of the multiple real impedance values ​​and the range of the multiple imaginary impedance values; The control module selects the effective matching inductance value from the multiple groups of matching inductance values ​​based on the sum of the variances of the multiple real impedance values ​​and the variances of the multiple imaginary impedance values ​​corresponding to the respective groups of matching inductance values, or the sum of the standard deviations of the multiple real impedance values ​​and the standard deviations of the multiple imaginary impedance values, or the sum of the ranges of the multiple real impedance values ​​and the ranges of the multiple imaginary impedance values.

3. The impedance matching box according to claim 2, characterized in that: The control module performs multiple iterative matching based on any set of matching inductance values, the first target impedance, the impedance detection value before each iterative matching, and the capacitance values ​​of the multiple variable matching capacitors before each iterative matching, including: The control module performs multiple iterative matching through the impedance matching network model until the reflection coefficient is lower than a preset value; The reflection coefficient is a ratio of a difference between the impedance detection value after each iterative matching and the first target impedance to a sum of the impedance detection value after each iterative matching and the first target impedance.

4. The impedance matching box according to claim 3, characterized in that: The control module performs multiple iterative matching through the impedance matching network model, including: The control module is used to input any group of matching inductance values, the first target impedance, the impedance detection value before each iterative matching, and the capacitance values ​​of the multiple variable matching capacitors before each iterative matching into the impedance matching network model, so as to obtain the target capacitance values ​​of the multiple variable matching capacitors through the impedance matching network model, and adjust the capacitance values ​​of the multiple variable matching capacitors based on the target capacitance values ​​of the multiple variable matching capacitors.

5. The impedance matcher according to any one of claims 1 to 4, characterized in that: The matching circuit includes a first variable matching capacitor and a second variable matching capacitor, one end of the first variable matching capacitor is connected to one end of the second variable matching capacitor; The other end of the first variable matching capacitor is connected to one end of the matching load via a first matching inductor, and / or the other end of the second variable matching capacitor is connected to the other end of the matching load via a second matching inductor.

6. The impedance matching box according to claim 5, characterized in that: The matching circuit includes a third variable matching capacitor, one end of the third variable matching capacitor is connected to the connection end of the first variable matching capacitor and the second variable matching capacitor, or one end of the third variable matching capacitor is connected to the connection end of the first variable matching capacitor and the second variable matching capacitor through a third matching inductor.

7. The impedance matcher according to any one of claims 1 to 4, characterized in that: The matching circuit comprises a first variable matching capacitor and a second variable matching capacitor, one end of the first variable matching capacitor is connected to one end of the second variable matching capacitor via a first matching inductor, and a connection end of the second variable matching capacitor and the matching inductor is connected to one end of the matching load; The other end of the first variable matching capacitor is connected to the other end of the matching load via a second matching inductor, and / or the other end of the second variable matching capacitor is connected to the other end of the matching load via a third matching inductor.

8. An impedance matching method, characterized in that: The impedance matcher applicable to the method includes a matching circuit, the matching circuit includes at least one matching inductor and a plurality of variable matching capacitors, the matching circuit is connected to a matching load, and the method includes: Acquire multiple groups of matching inductance values, and perform multiple iterative matching based on any group of matching inductance values, the first target impedance, the impedance detection value before each iterative matching, and the capacitance values ​​of the multiple variable matching capacitors before each iterative matching, to obtain matching data corresponding to any group of matching inductance values, wherein the matching data includes the impedance detection value after each iterative matching and the capacitance values ​​of the multiple variable matching capacitors after each iterative matching, and the impedance detection value is the sum of the actual impedance of the matching circuit and the impedance of the matching load; An effective matching inductance value is selected from the multiple groups of matching inductance values ​​based on the multiple groups of matching inductance values ​​and iterative matching data corresponding to each group of matching inductance values, and a target capacitance value of the multiple variable matching capacitors is determined based on the effective matching inductance value and a second target impedance.

9. The method according to claim 8, characterized in that The selecting effective matching inductance values ​​from the multiple groups of matching inductance values ​​based on the multiple groups of matching inductance values ​​and the iterative matching data corresponding to each group of matching inductance values ​​comprises: Obtaining the impedance real part value and the impedance imaginary part value of the matching load after each iterative matching based on any one group of matching inductance values ​​and the matching data corresponding to any one group of matching inductance values, so as to obtain multiple impedance real part values ​​and multiple impedance imaginary part values ​​of the matching load corresponding to any one group of matching inductance values; Obtaining the variance of the multiple real impedance values ​​and the variance of the multiple imaginary impedance values, or obtaining the standard deviation of the multiple real impedance values ​​and the standard deviation of the multiple imaginary impedance values, or obtaining the range of the multiple real impedance values ​​and the range of the multiple imaginary impedance values; The effective matching inductance value is selected from the multiple groups of matching inductance values ​​based on the sum of the variances of the multiple real impedance values ​​and the variances of the multiple imaginary impedance values ​​corresponding to the respective groups of matching inductance values, or the sum of the standard deviations of the multiple real impedance values ​​and the standard deviations of the multiple imaginary impedance values, or the sum of the ranges of the multiple real impedance values ​​and the ranges of the multiple imaginary impedance values.

10. The method according to claim 9, characterized in that The performing multiple iterative matching based on any set of matching inductance values, the first target impedance, the actual impedance of the matching circuit before each iterative matching, and the capacitance values ​​of the multiple variable matching capacitors before each iterative matching comprises: Perform multiple iterations of matching through the impedance matching network model until the reflection coefficient is lower than a preset value; The reflection coefficient is a ratio of a difference between the impedance detection value after each iterative matching and the first target impedance to a sum of the impedance detection value after each iterative matching and the first target impedance.

11. The method according to claim 10, characterized in that The performing multiple iterative matching through the impedance matching network model includes: Any one group of matching inductance values, the first target impedance, the impedance detection value before each iterative matching, and the capacitance values ​​of the multiple variable matching capacitors before each iterative matching are input into the impedance matching network model to obtain the target capacitance values ​​of the multiple variable matching capacitors through the impedance matching network model, and adjust the capacitance values ​​of the multiple variable matching capacitors based on the target capacitance values ​​of the multiple variable matching capacitors.

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