Impedance sampling device applied to matcher and semiconductor process equipment

Abstract

The invention provides an impedance sampling device applied to a matcher, an automatic matcher and semiconductor process equipment, and relates to the technical field of semiconductors, the impedance sampling device comprises a current sampling circuit, a voltage sampling circuit and a signal processing circuit; the current sampling circuit is used for collecting a current signal of a main loop and transmitting the current signal to the signal processing circuit; the voltage sampling circuit is used for collecting a voltage signal of a main loop and transmitting the voltage signal to the signal processing circuit; the signal processing circuit is used for calculating impedance based on the current signal and the voltage signal; the signal processing circuit is also used for adjusting the current coupling coefficient of the current sampling circuit according to the current signal so as to control the current measurement range of the current sampling circuit; the signal processing circuit is also used for adjusting the voltage coupling coefficient of the voltage sampling circuit according to the voltage signal so as to control the voltage measurement range of the voltage sampling circuit. The signal acquisition precision of the current signal and the voltage signal is improved, and the impedance calculation error can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to an impedance sampling device applied to a matcher, an automatic matcher and semiconductor process equipment. Background Art

[0002] Semiconductor process equipment usually uses radio frequency signals as plasma excitation sources, such as etching equipment, physical vapor deposition (PVD) equipment and plasma enhanced chemical vapor deposition (PECVD) equipment. These process equipment uses a radio frequency power supply (RF Generator) to provide radio frequency energy to the chamber to ionize special gases under high vacuum (such as argon, helium, nitrogen, oxygen, hydrogen, chlorine, hydrogen bromide, boron trichloride, octafluorocyclobutane, tetrafluoromethane and sulfur hexafluoride, etc.), generating 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 cavity 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.

[0003] In plasma equipment, since the plasma impedance is not 50 ohms and the RF power supply is 50 ohms, in order to achieve the maximum efficiency transmission of RF energy, it is necessary to connect an RF impedance matcher (RF Impedance Matcher) in the RF system to adjust the plasma impedance to a matching state of 50 ohms. According to the control method, the matcher can be divided into automatic matchers, manual matchers, and fixed matchers. The automatic matcher has become a preferred component for semiconductor equipment due to its automation, fast speed, and high precision. The automatic matcher includes a measuring unit, a control unit, an execution unit, and a matching circuit. The measuring unit is used to sample the current signal and voltage signal of the main circuit and perform impedance calculation to achieve impedance measurement, transmit the measured impedance to the control unit for matching calculation, and output the adjustment signal to the execution unit, thereby controlling the matching circuit to adjust to the required impedance point to achieve impedance matching.

[0004] The measurement unit of the relevant automatic matcher usually has a fixed coupling coefficient and a specific voltage measurement range and current measurement range. However, when the voltage or current measurement value exceeds the measurement range, the resolution is insufficient and cannot be measured. In order to meet the current and voltage measurement range requirements, the relevant matcher usually sets a larger current measurement range and voltage measurement range. However, when the current measurement range and voltage measurement range under a fixed resolution are large, when the measured voltage signal or current signal is small, the measurement signal error is large, which has a greater impact on the measurement accuracy of the voltage signal and current signal, and easily leads to an increase in the subsequent impedance calculation error, reduces the impedance calculation accuracy, and then causes matching mismatch. Summary of the invention

[0005] In view of this, the object of the present invention is to provide an impedance sampling device and semiconductor process equipment applied to a matcher, which can reduce the measurement errors of voltage and current caused by the large current and voltage measurement range of the impedance sampling device, improve the acquisition accuracy of current signals and voltage signals, reduce impedance calculation errors, and alleviate the problems of low matching accuracy or matching misalignment caused by impedance errors.

[0006] In order to achieve the above purpose, the technical solution adopted by the embodiment of the present invention is as follows:

[0007] In a first aspect, an embodiment of the present invention provides an impedance sampling device for a matcher, comprising: a current sampling circuit, a voltage sampling circuit and a signal processing circuit; the current sampling circuit is used to collect a current signal of a main loop and transmit the current signal to the signal processing circuit; wherein the main loop is an equivalent circuit of a radio frequency power supply connected to the matcher; the voltage sampling circuit is used to collect a voltage signal of the main loop and transmit the voltage signal to the signal processing circuit; the signal processing circuit is used to calculate impedance based on the current signal and the voltage signal; the signal processing circuit is also used to adjust a current coupling coefficient of the current sampling circuit according to the current signal to control a current measurement range of the current sampling circuit; wherein the current coupling coefficient is positively correlated with the current signal, and the current measurement range is positively correlated with the current coupling coefficient; the signal processing circuit is also used to adjust a voltage coupling coefficient of the voltage sampling circuit according to the voltage signal to control a voltage measurement range of the voltage sampling circuit; wherein the voltage coupling coefficient is positively correlated with the voltage signal, and the voltage measurement range is positively correlated with the voltage coupling coefficient.

[0008] Furthermore, the signal processing circuit is also used to confirm that the RF signal is turned on when the current signal is greater than a first current threshold, and to determine whether the current signal is less than a second current threshold. If the current signal is less than the second current threshold, the current coupling coefficient of the current sampling circuit is controlled to be a first value so that the current measurement range of the current sampling circuit is the first current range; if the current signal is greater than the second current threshold, the current coupling coefficient of the current sampling circuit is controlled to be a second value so that the current measurement range of the current sampling circuit is the second current range; wherein the second value is greater than the first value, and the maximum current value in the second current range is greater than the maximum current value in the first current range.

[0009] Furthermore, the signal processing circuit is also used to confirm that the RF signal is turned on when the voltage signal is greater than a first voltage threshold, and to determine whether the voltage signal is less than a second voltage threshold. If the voltage signal is less than the second voltage threshold, the voltage coupling coefficient of the voltage sampling circuit is controlled to be a third value so that the voltage measurement range of the voltage sampling circuit is the first voltage range; if the voltage signal is greater than the second voltage threshold, the voltage coupling coefficient of the voltage sampling circuit is controlled to be a fourth value so that the voltage measurement range of the voltage sampling circuit is the second voltage range; wherein the fourth value is greater than the third value, and the maximum voltage value in the second voltage range is greater than the maximum voltage value in the first voltage range.

[0010] Furthermore, the current sampling circuit includes a first induction coil, a second induction coil, a first switch and a load resistor; the first induction coil, the second induction coil and the load resistor are connected in series in sequence to form a closed loop, one end of the first switch is connected between the first induction coil and the second induction coil, the other end of the first switch is connected between the second induction coil and the load resistor, and the other end of the first switch is also connected to the signal processing circuit; the signal processing circuit is used to control the first switch to be in a closed state when the current signal is greater than the second current threshold; and control the first switch to be in an open state when the current signal is less than the second current threshold.

[0011] Further, when the first switch is closed, the first induction coil is coupled with the equivalent inductance in the main circuit, so that the current coupling coefficient of the current sampling circuit is a first coefficient; when the first switch is opened, the first induction coil and the second induction coil are jointly coupled with the equivalent inductance in the main circuit, so that the current coupling coefficient of the current sampling circuit is a second coefficient; wherein the first coefficient is greater than the second coefficient.

[0012] Furthermore, the voltage sampling circuit includes a first voltage-dividing capacitor, a second voltage-dividing capacitor and a second switch; the first voltage-dividing capacitor and the second voltage-dividing capacitor are both connected to the signal processing circuit, and the first voltage-dividing capacitor is connected in parallel with the second voltage-dividing capacitor, and the second switch is connected in series with the second voltage-dividing capacitor; the signal processing circuit is used to control the second switch to be in an open state when the voltage signal is less than the second voltage signal, and to control the second switch to be in a closed state when the voltage signal is greater than the second voltage signal.

[0013] Furthermore, the first voltage-dividing capacitor is also connected to the coupling capacitor in the main circuit. When the second switch is closed, the first voltage-dividing capacitor and the second voltage-dividing capacitor divide the voltage with the coupling capacitor so that the voltage coupling coefficient of the voltage sampling circuit is a third coefficient; when the second switch is opened, the first voltage-dividing capacitor divides the voltage with the coupling capacitor so that the voltage coupling coefficient of the voltage sampling circuit is a fourth coefficient; wherein the third coefficient is greater than the fourth coefficient.

[0014] Furthermore, the signal processing circuit includes an AD converter and a controller; the input end of the AD converter is respectively connected to the output end of the current sampling circuit and the output end of the voltage sampling circuit, the output end of the AD converter is connected to the input end of the controller, the first control end of the controller is electrically connected to the first switch, and the second control end of the controller is electrically connected to the second switch; the AD converter is used to convert the current signal and the voltage signal from analog signals into digital signals and transmit them to the controller.

[0015] In a second aspect, an embodiment of the present invention further provides an automatic matcher, comprising: an impedance sampling device, a control unit, an execution unit and a matching circuit as described in any one of the first aspects; the impedance sampling device is used to calculate the impedance of the RF power supply according to the collected voltage value and current value of the RF power supply, and transmit the impedance to the control unit; the control unit is used to perform matching calculations based on the impedance and output an adjustment signal to the execution unit; the execution unit is used to control the capacitance value of the matching circuit according to the adjustment signal so that the impedance of the RF power supply matches the impedance of the load connected to the automatic matcher.

[0016] In a third aspect, an embodiment of the present invention further provides a semiconductor process equipment, comprising: an upper RF power supply and an upper matcher, and / or a lower RF power supply and a lower matcher; the upper matcher and / or the lower matcher is the automatic matcher described in the second aspect.

[0017] The embodiment of the present invention provides an impedance sampling device, an automatic matcher and semiconductor process equipment applied to a matcher. By adaptively adjusting the current measurement range of a current sampling circuit and the voltage measurement range of a voltage sampling circuit according to the measured current signal and voltage signal, the sampled current signal and voltage signal can be matched with the measurement range of the sampling circuit, thereby reducing the measurement error of the voltage and current caused by the large current and voltage measurement range of the impedance sampling device, improving the acquisition accuracy of the current signal and the voltage signal, reducing the impedance calculation error, and alleviating the problem of low matching accuracy or matching misalignment caused by the impedance error.

[0018] Other features and advantages of the embodiments of the present invention will be described in the following description, or some features and advantages can be inferred or determined without doubt from the description, or can be learned by implementing the above-mentioned techniques of the embodiments of the present invention.

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic diagram of the structure of a typical ICP inductively coupled plasma device and its radio frequency matching system is shown;

[0022] Figure 2 A schematic diagram of the related automatic matching device structure is shown;

[0023] Figure 3 A schematic diagram showing the structure of a measurement unit of a related automatic matcher is shown;

[0024] Figure 4 A voltage sampling signal curve diagram of a measurement unit of a related automatic matching device is shown;

[0025] Figure 5 A schematic diagram of the structure of an impedance sampling device provided by an embodiment of the present invention is shown;

[0026] Figure 6 A circuit diagram of an impedance sampling device provided by an embodiment of the present invention is shown;

[0027] Figure 7a A schematic diagram of a voltage signal curve sampled when the voltage measurement range is 30-1000V provided in an embodiment of the present invention is shown;

[0028] Figure 7b A schematic diagram of a voltage signal curve sampled when the voltage measurement range is 6-200V provided in an embodiment of the present invention is shown;

[0029] Figure 8 A flow chart of adaptive impedance measurement of a measuring unit of an automatic matcher provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be described below in conjunction with the drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0031] Currently, see Figure 1 The schematic diagram of the structure of a typical ICP inductively coupled plasma device and its RF matching system is shown, the plasma chamber 11 includes an upper electrode and a lower electrode, the lower electrode includes a lower RF power supply 12, a lower matcher 13 and a base 14, the lower RF power supply 12 is connected to the lower matcher 13 and then to the base 14, and the wafer 15 is located above the base 14. The upper electrode includes an upper RF power supply 19, an upper matcher 10 and a coil 18, the upper RF power supply 19 is connected to the upper matcher 10 and then to the coil 18, and the coil 18 is located on the dielectric window 17. The plasma 16 is formed in the plasma chamber 11 through the joint action of the upper electrode and the lower electrode, and acts on the wafer 15 to achieve the process requirements.

[0032] See Figure 2 The schematic diagram of the structure of the related automatic matching device shown in the figure, the automatic matching device includes a measuring unit 21, a control unit 22, an execution unit 23 and a matching circuit unit 24, the measuring unit 21 at the input end is connected to the matching circuit unit 24 and then outputs, the testing unit 21 feeds back the measured voltage and current and other information to the control unit 22, and the control unit 22 calculates and outputs the adjustment signal to the execution unit 23, thereby controlling the matching circuit to be adjusted to the required circuit. The execution unit 23 of the automatic matching device is generally a stepping motor, which drives the operation of the vacuum capacitor 25 and the vacuum capacitor 26 in the matching circuit 24. There is a one-to-one correspondence between the position of the stepping motor and the capacitance value of the vacuum capacitor, so by adjusting the position of the stepping motor, the goal of matching the required capacitance value can be achieved, thereby achieving matching.

[0033] See Figure 3 The structural diagram of the measurement unit of the related automatic matching device shown in FIG. 1 includes a current sampling circuit 30, a voltage sampling circuit 31 and a signal processing circuit 32. Figure 3 As shown, the main loop equivalent circuit 33 includes an equivalent resistor 331, an equivalent inductor 332 and an equivalent capacitor 333, the current sampling circuit 30 includes an induction coil 301 and a load resistor 302, the voltage sampling circuit 31 includes a voltage-dividing capacitor 311, and the signal processing circuit 32 includes an AD converter 321 and a controller 322.

[0034] The induction coil 301 in the current sampling circuit and the equivalent inductance 332 of the main circuit use the transformer principle to generate a current sensing signal loaded on the load resistor 302, which represents the current value of the main circuit; the voltage sampling circuit 31 The voltage-dividing capacitor 311 and the equivalent capacitor 333 of the main circuit form a voltage sensing signal through capacitor voltage division, which represents the voltage value of the main circuit; the above-mentioned detected current and voltage output analog signals are converted into digital signals by the AD conversion device 321 and transmitted to the controller 322, and physical quantities such as impedance and power are calculated through signal processing for subsequent matching algorithms. Among them, the AD conversion device 321 mainly converts analog RF signals into digital signals (generally ADC or analog multiplier and other devices), and the controller 322 processes and converts digital signals, which can be a digital processor (DSP), a microcontroller unit MCU, an advanced RISC device ARM, a programmable array logic FPGA and other chips.

[0035] I(t)=ki*i(t)=f(M332-301, R302)*i(t)=I*cos(θ) (Formula 1)

[0036] V(t)=ku*u(t)= f(C333, C311)*u(t) =V*cos(θ+θ0) (Formula 2)

[0037] Among them, I(t) is the main loop current, i(t) is the sampling current amplitude of the current sampling circuit of the measuring unit, ki is the current coupling coefficient, which is related to the mutual inductance M332-301 and the load resistor 302, that is, f(M332-301, R302); V(t) is the main loop voltage, u(t) is the sampling voltage amplitude of the voltage sampling circuit of the measuring unit, ku is the voltage coupling coefficient, which is related to the voltage-dividing capacitors 333 and 311, that is, f(C333, C311).

[0038] After the automatic matcher starts running, the measurement unit collects information about voltage V, current I and phase Phase(θ). When the collected signal is greater than the thresholds Vth1 and Ith1, it is considered that the RF signal is turned on at this time, and the impedance and power are calculated based on voltage V, current I and phase Phase(θ). The calculated impedance value Z is used for the subsequent matching algorithm. If the measured impedance is Z, and the matching point is the characteristic impedance Z0 = 50 ohms, a control unit is required to give an adjustment signal to the execution unit after calculation, and then control the matching circuit to adjust to the required impedance point, and finally achieve matching.

[0039] The measurement unit of the related automatic matching device also has the following disadvantages:

[0040] 1. The measurement unit of the relevant automatic matcher usually samples a fixed coupling coefficient and a specific working range. For example, if the voltage coupling coefficient is 1000:1 and the resolution of the back-end ADC device is 0.03-1V, the measurable voltage range of the front-end main circuit is 30-1000V; if the current coupling coefficient is 70:1 and the resolution of the back-end ADC device is 0.03-1V, the measurable current range of the front-end main circuit is 2-70A; when the voltage or current measurement value exceeds the measurable range, such as when the voltage is less than 30V or greater than 1000V, it exceeds the measurable voltage range, and when the current is less than 2A or greater than 70A, it exceeds the measurable current range, then the resolution is insufficient and the current and voltage values ​​of the main circuit cannot be measured.

[0041] 2. In order to avoid over-range measurement, when the measurement range of the automatic matching device's measurement unit is large at a fixed resolution, the measurement linearity is poor under a smaller measurement signal; for example, when the voltage measurement range is 30-1000V, according to the device and circuit characteristics, the measurement difference of 1000V is 3% at 30V, and the measurement difference of 30V is 100% at 30V; this has a great impact on the signal measurement accuracy, which will increase the error of the back-end impedance calculation and cause matching misalignment. See, for example Figure 4 The voltage sampling signal curve diagram of the measurement unit of the related automatic matching device shown in the figure and the voltage sampling data table shown in Table 1 below:

[0042] Table 1 Voltage sampling data table

[0043] Main circuit voltage / V Voltage coupling coefficient Voltage coupling signal / mV error 30 1000 0 100％ 100 1000 70 30％ 200 1000 170 15％ 300 1000 270 10％ 400 1000 370 8％ 500 1000 470 6％ 600 1000 570 5％ 700 1000 670 4％ 800 1000 770 4％ 900 1000 870 3％ 1000 1000 970 3％

[0044] from Figure 4 It can be seen that when the voltage sampling signal is less than 400mV, the voltage signal error increases, and the voltage calculation error of the main circuit will also increase. As shown in Table 1 above, when the main circuit voltage is a small signal of 30V, the voltage signal error collected by the voltage sampling circuit can reach 100%, while the error is only 3% under a large signal of 1000V. The measurement accuracy of the voltage signal needs to be improved.

[0045] In order to improve the above problems, an embodiment of the present invention provides an impedance sampling device and a semiconductor process equipment applied to a matcher. The embodiment of the present invention is introduced in detail below.

[0046] This embodiment provides an impedance sampling device applied to a matching device. Figure 5 The impedance sampling device shown in the figure comprises: a current sampling circuit 51, a voltage sampling circuit 52 and a signal processing circuit 53;

[0047] like Figure 5As shown, the current sampling circuit 51 and the voltage sampling circuit 52 are electrically connected to the input end of the signal processing circuit 53 respectively. The current sampling circuit 51 is used to collect the current signal of the main loop 54 and transmit the current signal to the signal processing circuit; the voltage sampling circuit 52 is used to collect the voltage signal of the main loop 54 and transmit the voltage signal to the signal processing circuit. The above-mentioned main loop is an equivalent circuit of the RF power supply connected to the matcher, and the equivalent circuit includes an equivalent inductor and a coupling capacitor (not shown in the figure).

[0048] like Figure 5 As shown, two control terminals of the signal processing circuit 53 are electrically connected to the current sampling circuit 51 and the voltage sampling circuit 52 respectively, so as to input control signals to the current sampling circuit 51 and the voltage sampling circuit 52 .

[0049] The signal processing circuit 53 is also used to adjust the current coupling coefficient of the current sampling circuit according to the current signal to control the current measurement range of the current sampling circuit; wherein the current coupling coefficient is positively correlated with the current signal, and the current measurement range is positively correlated with the current coupling coefficient; that is, the smaller the current signal of the main circuit collected is, the smaller the current coupling coefficient of the current sampling circuit is controlled, thereby reducing the current measurement range of the current sampling circuit, thereby improving the current collection accuracy. The above-mentioned current measurement range is the current range of the main circuit that the current sampling signal can detect, that is, when the current of the main circuit is within the current measurement range, the current sampling circuit can measure the current signal of the main circuit.

[0050] The above-mentioned current sampling circuit can be connected in series with one or more induction coils on the basis of the relevant current sampling circuit, and each induction coil is correspondingly provided with a control switch. When the current sampling circuit has more induction coils connected in series, the current coupling coefficient is smaller, and the sampling accuracy is higher when the current signal of the main circuit is sampled within the small signal range. By controlling the opening and closing states of each control switch based on the signal processing circuit, the number of induction coils connected in series with the current sampling circuit can be controlled, thereby realizing the adjustment of the current coupling coefficient.

[0051] The signal processing circuit 53 is also used to adjust the voltage coupling coefficient of the voltage sampling circuit according to the voltage signal to control the voltage measurement range of the voltage sampling circuit; wherein the voltage coupling coefficient is positively correlated with the voltage signal, and the voltage measurement range is positively correlated with the voltage coupling coefficient. That is, the smaller the voltage signal of the main circuit collected, the smaller the voltage coupling coefficient of the voltage sampling circuit is controlled, thereby reducing the voltage measurement range of the voltage sampling circuit, thereby improving the voltage collection accuracy. The above-mentioned voltage measurement range is the voltage range of the main circuit that the voltage sampling circuit can measure, that is, when the voltage of the main circuit is within the voltage measurement range, the voltage sampling circuit can measure the voltage signal of the main circuit.

[0052] The voltage sampling circuit can be connected in parallel with one or more voltage-dividing capacitors on the basis of the relevant voltage sampling circuit, and each voltage-dividing capacitor is provided with a corresponding control switch. When the voltage sampling circuit has more voltage-dividing capacitors connected in parallel, the voltage coupling coefficient becomes larger, and the sampling accuracy of the voltage signal of the main circuit is higher when it is sampled within the large signal range. By controlling the opening and closing states of each control switch based on the signal processing circuit, the number of voltage-dividing capacitors connected in parallel with the voltage sampling circuit can be controlled, thereby realizing the adjustment of the voltage coupling coefficient. The control switch includes but is not limited to switching devices such as radio frequency switches, diodes and triodes.

[0053] The impedance sampling device applied to the matcher provided in the present embodiment can match the sampled current signal and voltage signal with the measurement range of the sampling circuit by adaptively adjusting the current measurement range of the current sampling circuit and the voltage measurement range of the voltage sampling circuit according to the measured current signal and voltage signal, thereby reducing the voltage and current measurement errors caused by the large current and voltage measurement ranges of the impedance sampling device, improving the acquisition accuracy of the current signal and the voltage signal, reducing the impedance calculation error, and alleviating the problem of low matching accuracy or matching misalignment caused by impedance error.

[0054] In one embodiment, in order to improve the current sampling accuracy, the signal processing circuit provided in this embodiment is also used to confirm that the RF signal is turned on when the current signal is greater than a first current threshold, and to determine whether the current signal is less than a second current threshold. If the current signal is less than the second current threshold, the current coupling coefficient of the current sampling circuit is controlled to be a first value so that the current measurement range of the current sampling circuit is the first current range; if the current signal is greater than the second current threshold, the current coupling coefficient of the current sampling circuit is controlled to be a second value so that the current measurement range of the current sampling circuit is the second current range; wherein the second value is greater than the first value, and the maximum current value in the second current range is greater than the maximum current value in the first current range.

[0055] The second current threshold may be 10% to 30% of the maximum operating current of the main circuit, preferably the maximum operating current*20%. For example, when the maximum operating current of the main circuit is 70A, the second current threshold may be 14A. When the current signal is less than the second current threshold, the number of inductors connected in series in the control current sampling circuit is increased to increase the mutual inductance of the current sampling circuit, thereby reducing the current coupling coefficient and narrowing the current measurement range of the current sampling circuit. At this time, when the main circuit operates in a smaller current signal range, the accuracy of the current sampling signal is higher.

[0056] When the collected current signal of the main circuit is less than the above-mentioned second current threshold, it indicates that the main circuit operates within a smaller current signal range (i.e., a small signal amplitude range). If the current measurement range of the current sampling circuit is larger, the current signal sampling accuracy will be lower. By controlling the current sampling circuit to be in a smaller current measurement range when the main circuit operates within a smaller current signal range, and controlling the current sampling circuit to be in a larger current measurement range when the main circuit operates within a larger current signal range, the measurement range of the current sampling circuit can be adaptively switched, so that the current measurement range of the current sampling circuit changes with the current current signal of the main circuit, thereby improving the acquisition accuracy of the current signal.

[0057] In one embodiment, in order to improve the voltage sampling accuracy, the signal processing circuit provided in this embodiment is also used to confirm that the RF signal is turned on when the voltage signal is greater than a first voltage threshold, and to determine whether the voltage signal is less than a second voltage threshold. If the voltage signal is less than the second voltage threshold, the voltage coupling coefficient of the voltage sampling circuit is controlled to be a third value so that the voltage measurement range of the voltage sampling circuit is the first voltage range; if the voltage signal is greater than the second voltage threshold, the voltage coupling coefficient of the voltage sampling circuit is controlled to be a fourth value so that the voltage measurement range of the voltage sampling circuit is the second voltage range; wherein the fourth value is greater than the third value, and the maximum voltage value in the second voltage range is greater than the maximum voltage value in the first voltage range.

[0058] The second voltage threshold may be 10% to 30% of the maximum operating voltage of the main circuit, preferably the maximum operating voltage*20%. For example, when the maximum operating voltage of the main circuit is 1000 V, the second voltage threshold may be 200 V. When the voltage signal is less than the second voltage threshold, the voltage sampling circuit is controlled to increase the number of voltage-dividing capacitors connected in parallel, so that the capacitance of the voltage sampling circuit is increased to reduce the voltage coupling coefficient and narrow the voltage measurement range of the voltage sampling circuit. At this time, when the main circuit operates in a smaller voltage signal range, the accuracy of the voltage sampling signal is higher.

[0059] When the collected voltage signal of the main circuit is less than the above-mentioned second voltage threshold, it indicates that the main circuit operates within a smaller voltage signal range (i.e., a small signal amplitude range). If the voltage measurement range of the voltage sampling circuit is larger, the voltage signal sampling accuracy will be lower. By controlling the voltage sampling circuit to be in a smaller voltage measurement range when the main circuit operates within a smaller voltage signal range, and controlling the voltage sampling circuit to be in a larger voltage measurement range when the main circuit operates within a larger voltage signal range, the measurement range of the voltage sampling circuit can be adaptively switched, so that the voltage measurement range of the voltage sampling circuit changes with the current voltage signal of the main circuit, thereby improving the acquisition accuracy of the voltage signal.

[0060] In one embodiment, see Figure 6The circuit diagram of the impedance sampling device is shown. The current sampling circuit 51 provided in this embodiment includes a first induction coil L1, a second induction coil L2, a first switch S1, and a load resistor R1.

[0061] As Figure 6 shown, the first induction coil L1, the second induction coil L2, and the load resistor R1 are connected in series in turn to form a closed loop. One end of the first switch S1 is connected between the first induction coil L1 and the second induction coil L2, and the other end of the first switch S1 is connected between the second induction coil L2 and the load resistor R1. Moreover, the other end of the first switch S1 is also connected to the signal processing circuit 53.

[0062] The signal processing circuit is configured to control the first switch S1 to be in an open state when the current signal is less than the second current threshold; and control the first switch S1 to be in a closed state when the current signal is greater than the second current threshold.

[0063] When the first switch is open, the coupling coil of the current sampling circuit includes the first induction coil L1 and the second induction coil L2. The series inductance value of the two coils is greater than the inductance of a single first induction coil L1. At this time, the mutual inductance M is in a high value state, the sampled current signal is a large signal, the current coupling coefficient Ki is in a lower proportion, and the sampling signal accuracy is higher in the small signal amplitude range of the main circuit.

[0064] The mutual inductance M-H = f(L0, L1 + L2), and the series inductance L of the current sampling circuit is L = L1 + L2.

[0065] The inductive reactance XL = jw*L1 + jw*L2 (where w is the angular frequency), and f(L0, L1 + L2) indicates that the mutual inductance M-H between the main circuit and the current acquisition circuit is a functional relationship related to L0 and L1 + L2.

[0066] When the first switch is closed, the coupling coil of the current sampling circuit is the first induction coil L1, and the second induction coil L2 is short-circuited. At this time, the mutual inductance M is in a low value state, the sampled current signal is a small signal, the current coupling coefficient Ki is in a larger proportion, and the sampling signal accuracy is higher in the large signal amplitude range of the main circuit.

[0067] The mutual inductance M-H = f(L0, L1), and the series inductance L of the current sampling circuit is L = L1.

[0068] The inductive reactance XL = jw*L1 < jwL19 + jwL25 (where w is the angular frequency), and f(L0, L1) indicates that the mutual inductance M-H between the main circuit and the current acquisition circuit is a functional relationship related to L0 and L1.

[0069] Therefore, M-L = f(L18, L19) < M-H = f(L18, L19 + L25);

[0070] Ki=k / ML>k / MH;

[0071] Among them, Ki is the current coupling coefficient, k is the fixed value of the mutual inductance coefficient, and MH is the mutual inductance between the main loop and the current sampling circuit inductance; the larger MH is, the smaller Ki is.

[0072] Since the larger MH is, the smaller Ki is, by controlling the first switch to be in an open state when the current signal is less than the second current threshold, MH can be increased to make the current coupling coefficient Ki smaller. At this time, when the main circuit is within the small signal amplitude range, the current sampling signal accuracy is higher, thereby improving the current signal sampling accuracy of the main circuit.

[0073] In one embodiment, when the first switch S1 is closed, the first induction coil L1 is coupled with the equivalent inductor L0 in the main loop equivalent circuit, so that the current coupling coefficient of the current sampling circuit is the first coefficient; the first induction coil L1 and the equivalent inductor coupling L0 use the transformer principle to generate a current sensing signal loaded on the load resistor R1, representing the current value of the main loop.

[0074] When the first switch S1 is turned on, the first induction coil L1 and the second induction coil L2 are coupled with the equivalent inductance L0 in the main loop equivalent circuit, so that the current coupling coefficient of the current sampling circuit is the second coefficient; wherein the first coefficient is greater than the second coefficient. The first induction coil L1 and the second induction coil L2 are coupled with the equivalent inductance L0 to generate a current sensing signal using the transformer principle and load it on the load resistor R1. By controlling the on and off state of the first switch S1, current sampling signals of different amplitudes can be output.

[0075] When the first switch S1 is closed, the current coupling coefficient is the first coefficient with a larger value, and the sampling accuracy is higher when the main circuit is in a large signal amplitude range; when the first switch S1 is opened, the current coupling coefficient is the second coefficient with a smaller value, and the sampling accuracy is higher when the main circuit is in a small signal amplitude range. By controlling the on and off state of the first switch S1, the current sampling range is improved.

[0076] In one embodiment, see Figure 6 As shown in the circuit diagram of the impedance sampling device, the voltage sampling circuit 52 provided in this embodiment includes a first voltage-dividing capacitor C1, a second voltage-dividing capacitor C2 and a second switch S2.

[0077] like Figure 6 As shown, the first voltage-dividing capacitor C1 and the second voltage-dividing capacitor C2 are both connected to the signal processing circuit, and the first voltage-dividing capacitor C1 and the second voltage-dividing capacitor C2 are connected in parallel, and the second switch S2 and the second voltage-dividing capacitor C2 are connected in series;

[0078] The signal processing circuit is used to control the second switch S2 to be in an open state when the voltage signal is less than the second voltage signal, and to control the second switch S2 to be in a closed state when the voltage signal is greater than the second voltage signal.

[0079] When the second switch S2 is in the closed state, the voltage-dividing capacitor of the voltage sampling circuit is a first voltage-dividing capacitor C1 and a second voltage-dividing capacitor C2 in parallel, and the parallel value of the two capacitors is greater than that of a single capacitor. At this time, the capacitance is in a high value state, and the voltage coupling coefficient Ku is relatively large. The voltage sampling signal accuracy is high within the large signal amplitude range of the main circuit, and the voltage measurement range of the voltage sampling circuit is a larger second voltage range (such as 30-1000V).

[0080] Capacitance CH = f(C0, C1 + C2);

[0081] Wherein, the parallel capacitor C of the voltage sampling circuit is C=C1 / / C1=C1+C2;

[0082] Capacitive reactance Xc = 1 / (jwC1+jwC2) (where w is the angular frequency)

[0083] f(C0, C1+C2) indicates that the capacitance CH is a function of C0 and C1+C2, Ku=C0<(C0+C1+C2) / C0.

[0084] When the second switch S2 is in the open state, the voltage-dividing capacitor is capacitor C1, and capacitor C2 is open. At this time, the capacitor is in a low value state, the voltage coupling coefficient Ku is relatively small, and the sampling signal accuracy is high when the main circuit has a small signal amplitude range; the voltage measurement range of the voltage sampling circuit is a smaller first voltage range (such as 6-200V).

[0085] Capacitance CL = f(C0, C1);

[0086] Wherein, the parallel capacitance of the voltage sampling circuit is C=C1 / / C1=C1+C2>C1;

[0087] Capacitive reactance Xc = 1 / jwC1>1 / (jwC1+jwC2) (where w is the angular frequency)

[0088] f(C0, C1) indicates that the capacitance CL is a function of C0 and C1.

[0089] Ku=(C0+C1) / C0<(C0+C1+C2) / C0;

[0090] Among them, Ku is the voltage coupling coefficient, C21 is the capacitance between the main loop and the voltage sampling circuit, C22 and C27 are the capacitances of the sampling circuit; the larger the voltage-dividing capacitance of the voltage sampling circuit, the larger Ku.

[0091] In one embodiment, the first voltage-dividing capacitor C1 is also connected to one end of the coupling capacitor C0 in the main loop equivalent circuit, and the other end of the coupling capacitor C0 is connected between the equivalent resistor R0 and the equivalent inductor L0. When the second switch S2 is closed, the first voltage-dividing capacitor C1 and the second voltage-dividing capacitor C2 divide the voltage with the coupling capacitor C0 so that the voltage coupling coefficient of the voltage sampling circuit is the third coefficient.

[0092] When the second switch S2 is turned on, the first voltage-dividing capacitor C1 and the coupling capacitor C0 divide the voltage to represent the voltage value of the main loop, so that the voltage coupling coefficient of the voltage sampling circuit is the fourth coefficient; wherein the third coefficient is greater than the fourth coefficient.

[0093] When the second switch S2 is closed, a voltage sensing signal is formed by voltage division between the first voltage-dividing capacitor C1 and the second voltage-dividing capacitor C2 in the voltage sampling circuit and the coupling capacitor C0 of the main circuit to represent the voltage value of the main circuit. When the second switch S2 is in different open and closed states, the voltage sampling circuit outputs voltage sampling signals of different amplitudes.

[0094] When the second switch S2 is closed, the voltage coupling coefficient is the third coefficient with a larger value, and the sampling accuracy is higher when the main circuit is in a large signal amplitude range; when the second switch S2 is opened, the voltage coupling coefficient is the fourth coefficient with a smaller value, and the sampling accuracy is higher when the main circuit is in a small signal amplitude range. By controlling the on and off state of the second switch S2, the voltage sampling range is improved.

[0095] In one embodiment, Figure 6 As shown, the signal processing circuit provided in this embodiment includes an AD converter ADC and a controller T1.

[0096] The input end of the AD converter ADC is connected to the output end of the current sampling circuit 51 and the output end of the voltage sampling circuit 52 respectively, the output end of the AD converter is connected to the input ends IN1 and IN2 of the controller T1, the first control end IO1 of the controller T1 is electrically connected to the first switch S1, and the second control end IO2 of the controller T1 is electrically connected to the second switch S2.

[0097] The AD converter ADC is used to convert the current signal and the voltage signal from analog signals into digital signals and transmit them to the controller T1.

[0098] The controller T1 is used to calculate the impedance and power based on the converted current signal and voltage signal, and output the calculated impedance and power through the output port OUT so as to be used in the subsequent matching algorithm. The controller can be a digital processor (DSP), a microcontroller unit MCU, an advanced RISC device ARM or a programmable array logic FPGA or other chips.

[0099] The impedance sampling device provided in this embodiment can adaptively adjust the measurement range of the sampling circuit according to the sampled voltage signal and current signal, reduce the measurement error by amplifying the sampling signal amplitude, thereby improving the accuracy of data acquisition, helping to reduce the error of subsequent impedance calculation, improving the impedance calculation accuracy, and reducing the problem of low matching accuracy or matching tuning mismatch caused by errors; and the improved impedance calculation accuracy helps to achieve fast and stable matching, improve matching stability, and improve data repeatability.

[0100] Exemplarily, this embodiment provides a case of sampling a voltage signal based on the above impedance sampling device. Assuming C0 = 1pF, C1 = 199pF, C2 = 800pF, the high voltage coupling coefficient Ku-H is 1000:1 when S2 is closed, and the low voltage coupling coefficient is 200:1 when S2 is open.

[0101] When the second switch S2 is closed, the voltage coupling coefficient Ku-H is 1000:1, the resolution of the back-end ADC device is 0.03-1V, and the voltage measurement range of the voltage sampling circuit is 30-1000V (that is, the main circuit voltage range that the voltage sampling circuit can measure is 30-1000V); when the second switch S2 is opened, the measured voltage coupling coefficient Ku-L is 200:1, and the voltage measurement range of the voltage sampling circuit is 6-200V. See, for example Figure 7a The voltage signal curve diagram of the voltage measurement range is 30-1000V and Figure 7b The voltage signal curve diagram shown is a sampled voltage signal curve when the voltage measurement range is 6-200V. Figure 7b It can be seen that the measurement accuracy of the voltage signal in the low-end voltage range is improved; by adaptively adjusting the coupling coefficient of the sampling circuit, the measurement range can be expanded from 30-1000V to 6-1000V; see the relationship between the main circuit voltage signal and the sampling error data shown in Table 2 below:

[0102] Table 2 Relationship between main circuit voltage signal and sampling error data

[0103] Main circuit voltage / V Voltage coupling coefficient Voltage coupling signal / mV error 6 200 24 20％ 10 200 44 12％ 20 200 94 6％ 30 200 144 4％ 40 200 194 3％ 50 200 244 2％ 100 200 494 1％ 200 200 994 1％ 300 1000 270 10％ 400 1000 370 8％ 500 1000 470 6％ 600 1000 570 5％ 700 1000 670 4％ 800 1000 770 4％ 900 1000 870 3％ 1000 1000 970 3％

[0104] It can be seen from Table 2 that by switching different voltage coupling coefficients when the main circuit voltage signal is in different intervals, the voltage signal measurement accuracy can be improved. For example, the 100% error is reduced to 4% error when the voltage signal is 30V, which effectively reduces the acquisition error of the voltage signal in the low voltage range.

[0105] Based on the above embodiment, this embodiment provides an example of using the above impedance sampling device to adaptively adjust the measurement unit of the automatic matching device, see Figure 8The flowchart of the automatic matching device's measurement unit adaptive impedance measurement is shown in the figure. The specific steps can be referred to as follows:

[0106] Step 1: After the operation starts, close the first switch S1 and open the second switch S2, so that the current sampling circuit and the voltage sampling circuit operate in a large measurement range.

[0107] Step 2: Collect voltage signal, current signal and phase information.

[0108] Step 3, determine whether the collected voltage signal V is greater than the first voltage threshold Vth1, and determine whether the collected current signal I is greater than the first current threshold Ith1; if yes, determine that the RF signal is turned on.

[0109] Step 4: determine whether the voltage signal and the current signal are small signals based on the controller.

[0110] The controller determines whether the current signal I is less than the second current threshold value Ith2. If so, the controller sends an opening switch instruction to the first switch S1, so that the current sampling circuit operates in the low current measurement range, and returns to execute the collection of voltage signal, current signal and phase information; if not, the first switch S1 remains in a closed state, so that the current sampling circuit operates in the high current measurement range.

[0111] The controller determines whether the voltage signal is less than the second voltage threshold Vth2. If so, the controller sends an open switch instruction to the second switch S2, so that the voltage sampling circuit operates in the low voltage measurement range (such as 6-200V), and returns to execute the collection of voltage signals, current signals and phase information; if not, the controller sends a closed switch instruction to the second switch S2, so that the voltage sampling circuit operates in the high voltage measurement range (such as 30-1000V).

[0112] Step 5: Calculate impedance and power based on the current signal and the voltage signal.

[0113] Corresponding to the impedance sampling device provided in the above embodiment, an embodiment of the present invention provides an automatic matcher, which includes: the impedance sampling device provided in the above embodiment, a control unit, an execution unit and a matching circuit;

[0114] The impedance sampling device is used to calculate the impedance of the radio frequency power supply according to the collected voltage value and current value of the radio frequency power supply, and transmit the impedance to the control unit;

[0115] The control unit is used to perform matching calculation according to the impedance and output an adjustment signal to the execution unit; the control unit and the controller in the signal processing circuit of the above-mentioned impedance sampling device can be the same control chip or different control chips.

[0116] The execution unit is used to control the capacitance value of the matching circuit according to the adjustment signal, so that the impedance of the radio frequency power supply matches the impedance of the load connected to the automatic matcher.

[0117] The execution unit of the automatic matcher is generally a stepper motor, which drives the operation of the vacuum capacitor and the vacuum capacitor in the matching circuit. There is a one-to-one correspondence between the position of the stepper motor and the capacitance of the vacuum capacitor. Therefore, by adjusting the position of the stepper motor, the goal of matching the required capacitance value is achieved, thereby achieving the impedance matching of the RF power supply and the load impedance connected to the matcher.

[0118] In a specific embodiment, the impedance sampling device calculates the impedance of the RF power supply based on the collected voltage value and current value of the RF power supply, and the signal processing circuit in the impedance sampling device calculates the impedance and power based on the current signal and the voltage signal when the current signal is greater than a first current threshold and the voltage signal is greater than a first voltage threshold.

[0119] The first current threshold can be a relatively small current value, and the value range of the first current threshold can be 0.1A to 0.2A; the first voltage threshold can be a relatively small voltage value, and the value range of the first voltage threshold can be 1A to 6A. When the current signal is greater than the first current threshold and the voltage signal is greater than the first voltage threshold, it indicates that the RF signal is turned on, and the collected impedance and power can be calculated based on the collected current signal and voltage signal of the main loop, where the calculation formula of the impedance Z and the power P can be:

[0120]

[0121] P=V·I (Formula 4)

[0122] Among them, Z is the impedance, V is the collected voltage signal of the main circuit, I is the collected current signal of the main circuit, θ is the phase, R is the real part of the impedance, X is the imaginary part of the impedance, cosθ is the phase cosine, sinθ is the phase sine, and P is the power.

[0123] Corresponding to the automatic matcher provided in the above embodiment, an embodiment of the present invention provides a semiconductor process equipment, which includes: an upper RF power supply and an upper matcher, and / or a lower RF power supply and a lower matcher; the upper matcher and / or the lower matcher are the automatic matcher provided in the above embodiment.

[0124] The semiconductor process equipment also includes: a coil and a base; an upper matcher is connected between an upper radio frequency power source and the coil, and a lower matcher is connected between a lower radio frequency power source and the base.

[0125] The above-mentioned semiconductor process equipment includes but is not limited to an etcher, a PVD equipment, a PECVD equipment, an ICP (inductively coupled plasma) chamber and a CCP (capacitively coupled plasma source) chamber.

[0126] In this embodiment, the matcher of the impedance sampling device provided by the above embodiment is set in the semiconductor process equipment, and the impedance detection accuracy of the impedance sampling device is improved, so that the matching stability of the matcher can be improved, and the matching time and power stability in the process can also be improved, thereby ensuring the stability of the process results.

[0127] The semiconductor process equipment provided in this embodiment has the same implementation principle and technical effects as those of the aforementioned embodiments. For the sake of brief description, for matters not mentioned in the semiconductor process equipment embodiment, reference may be made to the corresponding contents in the aforementioned device embodiment.

[0128] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0129] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0130] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. An impedance sampling device applied to a matching device, characterized in that: include: Current sampling circuit, voltage sampling circuit and signal processing circuit; The current sampling circuit is used to collect the current signal of the main loop and transmit the current signal to the signal processing circuit; wherein the main loop is an equivalent circuit of the radio frequency power supply connected to the matcher; The voltage sampling circuit is used to collect the voltage signal of the main circuit and transmit the voltage signal to the signal processing circuit; The signal processing circuit is used to adjust the current coupling coefficient of the current sampling circuit according to the current signal to control the current measurement range of the current sampling circuit; wherein the current coupling coefficient is positively correlated with the current signal, and the current measurement range is positively correlated with the current coupling coefficient; The signal processing circuit is also used to adjust the voltage coupling coefficient of the voltage sampling circuit according to the voltage signal to control the voltage measurement range of the voltage sampling circuit; wherein the voltage coupling coefficient is positively correlated with the voltage signal, and the voltage measurement range is positively correlated with the voltage coupling coefficient.

2. The impedance sampling device according to claim 1, characterized in that: The signal processing circuit is further used to confirm that the RF signal is turned on when the current signal is greater than a first current threshold, determine whether the current signal is less than a second current threshold, and if the current signal is less than the second current threshold, control the current coupling coefficient of the current sampling circuit to be a first value, so that the current measurement range of the current sampling circuit is the first current range; If the current signal is greater than the second current threshold, the current coupling coefficient of the current sampling circuit is controlled to be a second value so that the current measurement range of the current sampling circuit is a second current range; wherein the second value is greater than the first value, and the maximum current value in the second current range is greater than the maximum current value in the first current range.

3. The impedance sampling device according to claim 1, characterized in that: The signal processing circuit is also used to confirm that the RF signal is turned on when the voltage signal is greater than a first voltage threshold, and to determine whether the voltage signal is less than a second voltage threshold. If the voltage signal is less than the second voltage threshold, the voltage coupling coefficient of the voltage sampling circuit is controlled to be a third value so that the voltage measurement range of the voltage sampling circuit is the first voltage range; if the voltage signal is greater than the second voltage threshold, the voltage coupling coefficient of the voltage sampling circuit is controlled to be a fourth value so that the voltage measurement range of the voltage sampling circuit is the second voltage range; wherein the fourth value is greater than the third value, and the maximum voltage value in the second voltage range is greater than the maximum voltage value in the first voltage range.

4. The impedance sampling device according to claim 2, characterized in that: The current sampling circuit includes a first induction coil, a second induction coil, a first switch and a load resistor; The first induction coil, the second induction coil and the load resistor are connected in series in sequence to form a closed loop, one end of the first switch is connected between the first induction coil and the second induction coil, the other end of the first switch is connected between the second induction coil and the load resistor, and the other end of the first switch is also connected to the signal processing circuit; The signal processing circuit is used to control the first switch to be in a closed state when the current signal is greater than the second current threshold; and to control the first switch to be in an open state when the current signal is less than the second current threshold.

5. The impedance sampling device according to claim 4, characterized in that: When the first switch is closed, the first induction coil is coupled with the equivalent inductance in the main loop, so that the current coupling coefficient of the current sampling circuit is a first coefficient; when the first switch is opened, the first induction coil and the second induction coil are jointly coupled with the equivalent inductance in the main loop, so that the current coupling coefficient of the current sampling circuit is a second coefficient; wherein the first coefficient is greater than the second coefficient.

6. The impedance sampling device according to claim 4, characterized in that: The voltage sampling circuit includes a first voltage-dividing capacitor, a second voltage-dividing capacitor and a second switch; The first voltage-dividing capacitor and the second voltage-dividing capacitor are both connected to the signal processing circuit, and the first voltage-dividing capacitor is connected in parallel with the second voltage-dividing capacitor, and the second switch is connected in series with the second voltage-dividing capacitor; The signal processing circuit is used to control the second switch to be in an open state when the voltage signal is smaller than the second voltage signal, and to control the second switch to be in a closed state when the voltage signal is larger than the second voltage signal.

7. The impedance sampling device according to claim 6, characterized in that: The first voltage-dividing capacitor is also connected to the coupling capacitor in the main loop. When the second switch is closed, the first voltage-dividing capacitor and the second voltage-dividing capacitor divide the voltage with the coupling capacitor so that the voltage coupling coefficient of the voltage sampling circuit is a third coefficient. When the second switch is opened, the first voltage-dividing capacitor divides the voltage with the coupling capacitor so that the voltage coupling coefficient of the voltage sampling circuit is a fourth coefficient. The third coefficient is greater than the fourth coefficient.

8. The impedance sampling device according to claim 6, characterized in that: The signal processing circuit includes an AD converter and a controller; The input end of the AD converter is connected to the output end of the current sampling circuit and the output end of the voltage sampling circuit respectively, the output end of the AD converter is connected to the input end of the controller, the first control end of the controller is electrically connected to the first switch, and the second control end of the controller is electrically connected to the second switch; The AD converter is used to convert the current signal and the voltage signal from analog signals into digital signals and transmit them to the controller.

9. An automatic matcher, characterized in that: include: The impedance sampling device, control unit, execution unit and matching circuit according to any one of claims 1 to 8; The impedance sampling device is used to calculate the impedance of the RF power supply according to the collected voltage value and current value of the RF power supply, and transmit the impedance to the control unit; The control unit is used to perform matching calculation according to the impedance and output an adjustment signal to the execution unit; The execution unit is used to control the capacitance value of the matching circuit according to the adjustment signal, so that the impedance of the RF power supply matches the impedance of the load connected to the automatic matcher.

10. A semiconductor process equipment, characterized in that: include: An upper radio frequency power supply and an upper matching device, and / or a lower radio frequency power supply and a lower matching device; The upper matcher and / or the lower matcher is the automatic matcher according to claim 9.

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