WO2025002211A1 - 半导体工艺设备及最优阻抗值获取方法、扫频匹配方法 - Google Patents

半导体工艺设备及最优阻抗值获取方法、扫频匹配方法 Download PDF

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Publication number
WO2025002211A1
WO2025002211A1 PCT/CN2024/101805 CN2024101805W WO2025002211A1 WO 2025002211 A1 WO2025002211 A1 WO 2025002211A1 CN 2024101805 W CN2024101805 W CN 2024101805W WO 2025002211 A1 WO2025002211 A1 WO 2025002211A1
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Prior art keywords
impedance
power supply
matching
plasma etching
etching process
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PCT/CN2024/101805
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English (en)
French (fr)
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WO2025002211A9 (zh
Inventor
邹丽影
卫晶
韦刚
张晓博
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Beijing Naura Microelectronics Equipment Co Ltd
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Beijing Naura Microelectronics Equipment Co Ltd
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Priority to JP2025561433A priority Critical patent/JP2026513378A/ja
Priority to KR1020257035538A priority patent/KR20250167024A/ko
Publication of WO2025002211A1 publication Critical patent/WO2025002211A1/zh
Publication of WO2025002211A9 publication Critical patent/WO2025002211A9/zh
Anticipated expiration legal-status Critical
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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
    • H01J37/32082—Radio frequency generated discharge
    • H01J37/32174—Circuits specially adapted for controlling the RF discharge
    • H01J37/32183—Matching circuits
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32917—Plasma diagnostics
    • H01J37/32935—Monitoring and controlling tubes by information coming from the object and/or discharge
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/38—Impedance-matching networks
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
    • H10P72/00—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof
    • H10P72/04—Apparatus for manufacture or treatment
    • H10P72/0402—Apparatus for fluid treatment
    • H10P72/0418—Apparatus for fluid treatment for etching
    • H10P72/0421—Apparatus for fluid treatment for etching for drying etching
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
    • H01J2237/32—Processing objects by plasma generation
    • H01J2237/33—Processing objects by plasma generation characterised by the type of processing
    • H01J2237/334—Etching

Definitions

  • the present application belongs to the field of semiconductor process technology, and in particular relates to a semiconductor process equipment, an optimal impedance value acquisition method, and a frequency sweep matching method.
  • Method 2 Use an RF power supply with a frequency sweep function to automatically adjust the center frequency of the power supply output for impedance matching.
  • Method 3 Impedance matching is completed by combining an RF power supply with a frequency sweeping function with an impedance matcher.
  • This method in which an RF power supply with a frequency sweeping function and an impedance matcher cooperate with each other, can quickly complete the plasma ignition matching process and can complete the plasma ignition matching task under different conditions. Therefore, in the plasma etching machine It is increasingly widely used in impedance matching.
  • the impedance matching method of the third method mentioned above is prone to signal oscillation of the RF power supply output due to inappropriate load impedance of the RF power supply, which in turn leads to failure of frequency sweep matching of the RF power supply, that is, failure of plasma ignition.
  • the embodiments of the present application provide a semiconductor process equipment and a method for obtaining an optimal impedance value and a frequency sweeping matching method, which are intended to solve the technical problem that the existing method of completing impedance matching by combining an RF power supply with a frequency sweeping function with an impedance matcher is prone to oscillation of the signal output by the RF power supply due to inappropriate load impedance of the RF power supply, thereby causing failure of frequency sweeping matching of the RF power supply.
  • an embodiment of the present application provides a method for obtaining an optimal impedance value of an impedance matcher, wherein the impedance matcher is used to adjust the rear-end impedance of a radio frequency power supply in real time, and the impedance matcher includes a variable impedance device for impedance adjustment.
  • the method includes the following steps:
  • the current matching impedance value is recorded as the optimal impedance value.
  • the step of adjusting the operating frequency of the RF power source includes:
  • the operating frequency of the RF power supply is gradually modified from one of the minimum value and the maximum value of the operating frequency range to the other of the minimum value and the maximum value of the operating frequency range according to a first preset adjustment step.
  • the preset requirement includes that the relationship curve has an operating frequency point corresponding to the power reflection coefficient being less than 0.01 and that the relationship curve does not have an area where the power reflection coefficient oscillates.
  • the method further includes:
  • the relationship curve generated by adjusting the working frequency of the radio frequency power supply is adjusted until the obtained relationship curve meets the preset requirements, and the current matching impedance value is recorded as the optimal impedance value.
  • variable impedance device includes a first variable capacitor and a second variable capacitor
  • the step of adjusting the variable impedance device to a preset impedance value includes: adjusting the first variable capacitor to a first preset capacitor position, and adjusting the second variable capacitor to a second preset capacitor position;
  • the step of recording the matching impedance value of the variable impedance device at this time after the impedance matching adjustment is completed comprises: recording the first capacitance position of the first variable capacitor and the second capacitance position of the second variable capacitor at this time after the impedance matching adjustment is completed;
  • the step of fixing the impedance of the variable impedance device at the matching impedance value comprises: fixing the first variable capacitor at the first capacitor position, and fixing the second variable capacitor at the second capacitor position;
  • the step of recording the current matching impedance value as the optimal impedance value comprises: recording the current The first capacitor position is recorded as a first optimal capacitor position, and the current second capacitor position is recorded as a second optimal capacitor position.
  • it also includes:
  • the current value of the first capacitor position is gradually reduced according to the second preset adjustment step, and the current value of the second capacitor position is gradually reduced according to the third preset adjustment step, thereby achieving the adjustment of the matching impedance value.
  • the first variable capacitor is connected between the output terminal of the RF power supply and ground, and the second variable capacitor is connected between the output terminal of the RF power supply and a load;
  • the third preset adjustment step length is greater than the second preset adjustment step length.
  • an embodiment of the present application provides a method for sweeping frequency matching of an RF power supply of a semiconductor process device, wherein the semiconductor process device includes an RF power supply with a sweeping frequency function and an impedance matcher for adjusting the rear-end impedance of the RF power supply in real time, wherein the impedance matcher includes a variable impedance device for impedance adjustment, and the sweeping frequency matching method includes the following steps:
  • the optimal impedance value of the variable impedance device is obtained by using the above method
  • the frequency sweep mode of the radio frequency power supply is turned on to achieve plasma ignition matching.
  • the step of obtaining the optimal impedance value of the variable impedance device includes:
  • the optimal impedance value of the variable impedance device is obtained and recorded and stored in a preset process parameter list.
  • the step of determining whether the plasma etching process to be performed is an existing plasma etching process includes:
  • the plasma etching to be performed is stored in the preset process parameter list process, to determine whether the plasma etching process to be performed is an existing plasma etching process;
  • the plasma etching process to be performed is stored in the preset process parameter list, determining that the plasma etching process to be performed is an existing plasma etching process;
  • the plasma etching process to be performed is not stored in the preset process parameter list, it is determined that the plasma etching process to be performed is not an existing plasma etching process.
  • the step of determining whether the plasma etching process to be performed is an existing plasma etching process includes:
  • the optimal impedance value of the plasma etching process to be performed is a default state, determining that the plasma etching process to be performed is not an existing plasma etching process
  • the optimal impedance value of the plasma etching process to be performed is not a default state, it is determined that the plasma etching process to be performed is an existing plasma etching process.
  • the step of obtaining the optimal impedance value of the variable impedance device further includes:
  • the plasma etching process to be performed is an existing plasma etching process, the plasma etching process to be performed and the corresponding stored optimal impedance value are found in the preset process parameter list.
  • an embodiment of the present application provides a semiconductor process equipment, comprising an RF power supply with a frequency sweeping function, an impedance matcher for adjusting the rear-end impedance of the RF power supply in real time, and a controller, wherein the impedance matcher comprises a variable impedance device for impedance adjustment, and the controller comprises a processor, a memory, and a program stored in the memory and executable on the processor, wherein the program, when executed by the processor, implements the steps of the method for obtaining the optimal impedance value of the impedance matcher or executes the steps of the frequency sweeping matching method.
  • the semiconductor process equipment when the semiconductor process equipment performs RF power sweep matching, it can first find the optimal impedance value of the variable impedance device according to the specific process conditions (i.e., the plasma etching process to be performed currently), and the optimal impedance value can ensure that the relationship curve between the working frequency of the RF power supply and the power reflection coefficient meets the preset requirements, that is, find the appropriate load of the RF power supply to ensure that when the RF power supply is swept, the relationship curve between the working frequency of the RF power supply and the power reflection coefficient satisfies the one-to-one corresponding change relationship, so that after the impedance of the variable impedance device is fixed at the optimal impedance value, the sweep mode of the RF power supply can be turned on, that is, the power supply sweep mode can be turned on at the appropriate load, so that the plasma can be quickly ignited, avoiding the frequency oscillation area, and then achieving plasma ignition matching. It can be seen that the present technical solution can effectively avoid the problem of signal oscillation output by the specific
  • FIG. 1 is a working principle diagram of an existing method of achieving impedance matching by combining a radio frequency power supply with a frequency sweeping function with an impedance matcher.
  • FIG. 2 is a graph showing the relationship between the operating frequency and the power reflection coefficient of the RF power supply when the RF power supply shown in FIG. 1 fails in frequency sweeping.
  • FIG3 is a schematic diagram of a partial enlargement of the relationship curve between the operating frequency and the power reflection coefficient of the RF power supply shown in FIG2.
  • FIG. 4 is a working principle diagram of the power supply load of the RF power supply shown in FIG. 1 .
  • FIG. 5 is a flowchart of a method for obtaining an optimal impedance value of an impedance matcher provided in an embodiment of the present application.
  • FIG. 6 is another flowchart of a method for obtaining an optimal impedance value of an impedance matcher provided in an embodiment of the present application.
  • FIG. 7 is a flowchart of a frequency sweep matching method for semiconductor process equipment provided in an embodiment of the present application.
  • FIG. 8 is a graph showing the relationship between the operating frequency of the RF power supply and the power reflection coefficient in the swept frequency matching method shown in FIG. 7 .
  • FIG. 9 is a schematic structural diagram of an L-type impedance matcher in the swept frequency matching method shown in FIG. 7 .
  • FIG. 10 is a flowchart of step S110 of the sweep frequency matching method shown in FIG. 7 .
  • a plasma etching machine uses a radio frequency power supply with a frequency sweeping function in combination with an impedance matcher to complete impedance matching. Its working principle is shown in FIG1 , and is generally divided into the following two stages: In the first stage, the variable capacitance of the impedance matcher is fixed, and the frequency sweeping function of the radio frequency power supply is turned on. At this time, the power detection module of the radio frequency power supply uses a detection control circuit to detect the incident power and the reflected power through high-frequency measurement inductance, and obtains the power reflection coefficient ⁇ through calculation, and provides the signal to the frequency control module.
  • the frequency control module uses the reflection coefficient ⁇ as an input variable combined with the frequency sweeping matching algorithm to calculate the frequency adjustment amount, and feeds the frequency adjustment amount back to the radio frequency signal source to realize the impedance matching feedback process of automatically adjusting the working frequency of the radio frequency power supply.
  • the frequency sweeping function of the radio frequency power supply is used for preliminary matching.
  • the reflected power in the line can be reduced to 5%-10% of the incident power, which helps the plasma to start quickly.
  • the working frequency of the radio frequency power supply is fixed, and the automatic adjustment mode of the impedance matcher is turned on. At this time, the sensor of the impedance matcher will detect the voltage V and current I of the signal in the line.
  • the impedance matching signal from the input end of the impedance matcher to the impedance matcher can be obtained.
  • the input impedance amplitude Mag and phase Phase information seen from the output end of the matcher are used as input variables of the automatic matching algorithm.
  • the controller calculates the adjustment amount of the stepper motor based on the variables provided by the sensor and the automatic matching algorithm, and then changes the capacitance value of the tunable capacitor components C1 and C2. After fine-tuning the capacitance position of C1 and C2, the reflected power in the line is reduced to less than 1%, completing the final matching.
  • this method of cooperating with the RF power supply with a sweeping frequency function and the impedance matcher can quickly complete the plasma ignition matching process, and can complete the plasma ignition matching task under different conditions. Therefore, it is increasingly widely used in the impedance matching of plasma etching machines.
  • this impedance matching method still has the following problems: when using the frequency sweeping function of the RF power supply to achieve plasma ignition, the RF power supply adjusts the output frequency of the RF power supply by judging the relationship between the power reflection coefficient and the operating frequency, and finally finds the operating frequency point with the lowest power reflection coefficient to complete the plasma ignition matching process. Therefore, in order to achieve a fast and stable plasma ignition process, when the RF power supply performs frequency sweeping matching, it is necessary to ensure that the power reflection coefficient in the line and the operating frequency of the RF power supply are in a one-to-one corresponding relationship.
  • the signal output by the RF power supply may have an oscillation phenomenon.
  • the voltage signal in the line is composed of the incident voltage wave U i (z) and the reflected voltage wave Ur (z), where Ur (z) is related to the load reflection coefficient ⁇ L.
  • the load reflection coefficient ⁇ L is different, which leads to different amplitudes (U 1 , U 2 ) of the voltage wave at the MOS tube M 1 in the power amplifier.
  • the overvoltage, overcurrent, and dissipation protection of the MOS tube M1 will be triggered.
  • the signal output by the RF power supply will oscillate as shown in Figures 2 and 3.
  • the power load Z L of the RF power supply consists of two parts: the first part is the impedance Z M of the matching network of the impedance matcher, and the second part is the plasma impedance Z P.
  • the variable capacitors C1 and C2 of the impedance matcher are fixed at the position (C1_a, C2_a) after the plasma ignition matching.
  • the power load Z L may cause the signal output by the RF power supply to oscillate, and finally the RF power supply sweep frequency matching fails.
  • the embodiment of the present application provides a method for obtaining an optimal impedance value of an impedance matcher, wherein the impedance matcher is used to adjust the impedance of the rear end of a radio frequency power supply in real time to cooperate with the radio frequency power supply to quickly complete the plasma ignition matching of semiconductor process equipment, and the impedance matcher includes a variable impedance device for impedance adjustment.
  • the method may specifically include the following steps:
  • Step S11 adjusting the impedance of the variable impedance device to a preset impedance value.
  • the purpose of obtaining the optimal impedance value of the impedance matcher in the embodiment of the present application is mainly to perform frequency sweep matching service for the RF power supply of the semiconductor process equipment in the future. Therefore, the specific structure of the impedance matcher can refer to Figures 1 and 4, that is, the impedance matcher will include a variable impedance device for impedance adjustment. Further, the variable impedance device may specifically include a first variable capacitor C1 and a second variable capacitor C2.
  • obtaining the optimal impedance value of the impedance matcher should include obtaining The first optimal capacitance position of the first variable capacitor C1 and the second optimal capacitance position of the second variable capacitor C2 are obtained, that is, when the first variable capacitor C1 is at the first optimal capacitance position and the second variable capacitor C2 is at the second optimal capacitance position, the impedance of the variable impedance device of the impedance matcher is the optimal impedance value.
  • the impedance of the variable impedance device should be adjusted to a reasonable impedance value before starting to search (that is, the impedance of the variable impedance device is adjusted to a preset impedance value, which may specifically include adjusting the first variable capacitor to the first preset capacitance position and adjusting the second variable capacitor to the second preset capacitance position, for example, at the (50%, 50%) position).
  • Step S12 starting the radio frequency power supply, and when the frequency sweeping function of the radio frequency power supply is turned off, adjusting the impedance of the variable impedance device by using an automatic matching algorithm to perform impedance matching adjustment.
  • the RF power supply can be started, and when the frequency sweep function of the RF power supply is turned off, the impedance of the variable impedance device is adjusted using the automatic matching algorithm to perform impedance matching adjustment, that is, the impedance of the variable impedance device is adjusted through the automatic adjustment mode of the impedance matcher itself (specifically, the capacitance positions of the first variable capacitor C1 and the second variable capacitor C2 are adjusted respectively, that is, the specific capacitance values of the first variable capacitor C1 and the second variable capacitor C2) to complete the impedance matching adjustment.
  • Step S13 After the impedance matching adjustment is completed, the matching impedance value of the variable impedance device is recorded, and the RF power supply is turned off.
  • the system can automatically record the matching impedance value of the variable impedance device at this time (and can further record the first capacitance position of the first variable capacitor C1 and the second capacitance position of the second variable capacitor C2 at this time).
  • the matching impedance value of the variable impedance device at this time is The record is obtained after the matcher completes the impedance matching adjustment.
  • the first capacitance position of the first variable capacitor C1 can specifically coincide with the matching position C1_a of the first variable capacitor C1 in the related technology
  • the second capacitance position of the second variable capacitor C2 can specifically coincide with the matching position C2_a of the second variable capacitor C2 in the related technology
  • Step S14 after fixing the impedance of the variable impedance device at the matching impedance value, turning on the RF power supply again.
  • the impedance of the variable impedance device can be fixed at the matching impedance value (specifically, the first variable capacitor C1 can be fixed at the first capacitance position and the second variable capacitor C2 can be fixed at the second capacitance position), and then the RF power supply can be turned on again to make corresponding preliminary preparations for the subsequent acquisition of the relationship curve between the operating frequency and the power reflection coefficient of the RF power supply under the current matching impedance value.
  • Step S15 adjusting the operating frequency of the radio frequency power supply, obtaining the corresponding relationship between the operating frequency of the radio frequency power supply and the power reflection coefficient obtained in each adjustment, so as to generate a corresponding relationship curve.
  • the impedance of the variable impedance device is fixed at the matching impedance value (specifically, the first variable capacitor can be fixed at the first capacitor position and the second variable capacitor can be fixed at the second capacitor position) through the above method steps, and the RF power supply is turned on again, the corresponding relationship between the operating frequency of the RF power supply obtained by each adjustment and the power reflection coefficient can be obtained by adjusting the operating frequency of the RF power supply to generate a corresponding relationship curve.
  • the corresponding power reflection coefficient under the current operating frequency of the RF power supply can be recorded once, and then the corresponding relationship between the operating frequency of the RF power supply obtained by each adjustment and the power reflection coefficient can be obtained under multiple adjustment records to generate a corresponding relationship curve, that is, the relationship curve between the operating frequency of the RF power supply and the power reflection coefficient under the current matching impedance value (or the current first capacitor position and the second capacitor position).
  • Step S16 When the relationship curve meets the preset requirement, the current matching impedance value is recorded as the optimal impedance value.
  • the preset requirements may specifically include the existence of an operating frequency point corresponding to a power reflection coefficient less than 0.01 in the relationship curve and an area where the power reflection coefficient does not oscillate, wherein the existence of an operating frequency point corresponding to a power reflection coefficient less than 0.01 in the relationship curve can ensure that there is a frequency point for plasma ignition matching, so that the plasma can be successfully ignited and matched.
  • the absence of an area where the power reflection coefficient oscillates in the relationship curve can ensure that the relationship curve between the operating frequency of the RF power supply and the power reflection coefficient satisfies a one-to-one corresponding variation relationship, and can also ensure successful ignition matching of the plasma.
  • the optimal impedance value of the impedance matcher (or obtaining the first optimal capacitance position of the first variable capacitor C1 and obtaining the second optimal capacitance position of the second variable capacitor C2) through the method of the embodiment of the present application, it can be ensured that when the impedance of the variable impedance device used for impedance adjustment of the impedance matcher is fixed at the optimal impedance value, when the corresponding RF power supply is swept, the relationship curve between the operating frequency and the power reflection coefficient of the RF power supply can satisfy a one-to-one corresponding change relationship, thereby ensuring successful plasma ignition matching.
  • the process of executing the above method step "adjusting the operating frequency of the RF power supply” is as follows: within the operating frequency range of the RF power supply, the operating frequency of the RF power supply is gradually modified from one of the minimum value and the maximum value of the operating frequency range to the minimum value of the operating frequency range according to the first preset adjustment step. and the other of the maximum values.
  • the operating frequency of the RF power supply is gradually modified from 12.882 MHz to 14.238 MHz in steps of 0.1 MHz, and the power reflection coefficient corresponding to each operating frequency of the RF power supply is recorded to obtain the relationship curve between the operating frequency of the RF power supply and the power reflection coefficient under the current matching impedance value (i.e., the matching impedance value corresponding to fixing the first variable capacitor at the first capacitor position and fixing the second variable capacitor at the second capacitor position and the power load).
  • the matching impedance value of the variable impedance device found for the first time through the above method steps is recorded after the impedance matcher completes the impedance matching adjustment. Therefore, at this time, the matching impedance value of the variable impedance device is also the matching impedance value of the related technology, that is, at this time, the first capacitance position of the first variable capacitor C1 can specifically coincide with the matching position C1_a of the first variable capacitor C1 in the related technology, and the second capacitance position of the second variable capacitor C2 can specifically coincide with the matching position C2_a of the second variable capacitor C2 in the related technology.
  • the method of completing impedance matching by combining an RF power supply with a frequency sweeping function with an impedance matcher in the related art is that when the RF power supply performs frequency sweeping matching, the impedance of the variable impedance device of the impedance matcher is fixed at the matching impedance value (that is, the first variable capacitor C1 and the second variable capacitor C2 are fixed at the matching positions C1_a and C2_a).
  • the relationship curve between the operating frequency (Frequency) of the RF power supply and the power reflection coefficient ( ⁇ 2 ) shown in Figures 2 and 3 will appear.
  • the RF power supply is sweeping, its operating frequency enters the oscillation area and cannot jump out and find the operating frequency point where the power reflection coefficient is less than 0.1, which causes the frequency sweeping matching of the RF power supply to fail.
  • some electronegative gases HBr, CF4 , etc.
  • the matching impedance value i.e., the capacitor position C1_a and C2_a
  • the power reflection coefficient oscillation problem will occur more easily. This is because when using the matching method of the relevant technology, there is no RF power
  • the fixed position of the capacitor of the impedance matcher during source frequency sweep matching is optimized to obtain the relationship curve between the operating frequency of the RF power supply and the power reflection coefficient in the line in advance, so the successful frequency sweep matching of the RF power supply cannot be guaranteed.
  • the work of "obtaining and finding the relationship curve between the power frequency and the power reflection coefficient of the optimal impedance value of the variable impedance device (i.e., the first variable capacitor C1 and the second variable capacitor C2 at the appropriate fixed position)" in the embodiment of the present application is exactly the part missing from the solution of the related technology, which is the root cause of the failure of the power frequency sweep of the solution of the related technology. If this step is not performed, after the frequency sweep function of the RF power supply is turned on, it cannot be guaranteed that each frequency sweep of the RF power supply will be matched successfully.
  • the method further includes:
  • Step S17 When the relationship curve does not meet the preset requirement, adjust the matching impedance value.
  • the matching impedance value (or the first capacitor position and the second capacitor position) needs to be further optimized, that is, the matching impedance value (or the first capacitor position and the second capacitor position) needs to be further adjusted to gradually find the optimal impedance value of the variable impedance device (or the first optimal capacitor position of the first variable capacitor and the second optimal capacitor position of the second variable capacitor).
  • Step S18 After obtaining each matching impedance value adjustment, the relationship curve generated by adjusting the working frequency of the RF power supply is adjusted until the obtained relationship curve meets the preset requirements, and the current matching impedance value is recorded as the optimal impedance value.
  • the optimal impedance value of the impedance matcher (or obtaining the first optimal capacitance position of the first variable capacitor C1 and obtaining the second optimal capacitance position of the second variable capacitor C2) through the method of the embodiment of the present application, it can be ensured that when the impedance of the variable impedance device used for impedance adjustment of the impedance matcher is fixed at the optimal impedance value, when the corresponding RF power supply is swept, the relationship curve between the operating frequency and the power reflection coefficient of the RF power supply can satisfy a one-to-one corresponding change relationship, thereby ensuring successful plasma ignition matching.
  • the current value of the first capacitor position can be gradually reduced according to the second preset adjustment step, and the current value of the second capacitor position can be gradually reduced according to the third preset adjustment step.
  • the embodiment of the present application provides a frequency sweeping matching method for a semiconductor process device.
  • the semiconductor process device may include a radio frequency power supply with a frequency sweeping function and an impedance matcher for adjusting the impedance of the rear end of the radio frequency power supply in real time.
  • the impedance matcher includes a variable impedance device for impedance adjustment.
  • the frequency sweeping matching method specifically includes the following steps:
  • Step S110 according to the plasma etching process to be currently performed, using the method provided in the above embodiment, the optimal impedance value of the variable impedance device is obtained.
  • the frequency sweeping matching method of the embodiment of the present application is a further improvement based on the method of completing impedance matching by combining an RF power supply with a frequency sweeping function with an impedance matcher in the related art. Therefore, the specific structure of the RF power supply and the impedance matcher can be referred to as shown in FIG1. In order to avoid the phenomenon of signal oscillation output by the RF power supply due to inappropriate load impedance of the RF power supply, which leads to the problem of failure of frequency sweeping matching of the RF power supply.
  • the appropriate load of the RF power supply under the current plasma etching process to be executed is first found, that is, the optimal impedance value of the variable impedance device (or the first optimal capacitance position of the first variable capacitor C1 and the second optimal capacitance position of the second variable capacitor C2) is obtained to ensure that when the RF power supply is swept, the relationship curve between the operating frequency of the RF power supply and the power reflection coefficient satisfies the one-to-one corresponding variation relationship shown in FIG8.
  • Step S120 fixing the impedance of the variable impedance device at the optimal impedance value.
  • the impedance of the variable impedance device can be further fixed at the optimal impedance value (specifically, the first variable capacitor can be fixed at the first optimal capacitance position and the second variable capacitor can be fixed at the second optimal capacitance position).
  • the RF power supply can have a suitable load.
  • Step S130 starting the frequency sweep mode of the RF power supply to achieve plasma ignition matching.
  • the impedance of the variable impedance device is fixed at the optimal impedance value (or the first optimal capacitance position of the first variable capacitor C1 and the second optimal capacitance position of the second variable capacitor C2) through the above method steps, that is, after the RF power supply has a suitable load, the sweep mode of the RF power supply is turned on, and the plasma can be quickly ignited by turning on the power sweep mode at the suitable load, avoiding the frequency oscillation region, thereby achieving a stable and repeatable ignition matching process for the plasma.
  • the input admittance from the output of the RF power supply to the plasma is G L
  • the first variable capacitor C1 only affects the imaginary part of the input admittance
  • the second variable capacitor C2 affects not only the real part of the input admittance but also the imaginary part of the input admittance.
  • the only way to obtain a suitable power supply load Z L is to modify the impedance Z M of the matching network.
  • the impedance value of the etcher chamber is too large before the plasma starts, so the position of C2 can be reduced by 2% and the position of C1 can be reduced by 1%, that is, the third preset adjustment step mentioned above is greater than the second preset adjustment step, so as to quickly increase the impedance value corresponding to the matching network, and then repeat the process of finding the capacitor position.
  • the relationship curve between the operating frequency and the power reflection coefficient of the RF power supply as shown in Figure 8 can be finally obtained.
  • the specific process of performing the above method step of “according to the plasma etching process to be performed, using the method provided in the above embodiment, obtaining the optimal impedance value of the variable impedance device” is as follows:
  • Step S111 determining whether the plasma etching process to be performed is an existing plasma etching process.
  • an existing plasma etching process generally refers to a plasma etching process that has automatically found and saved the optimal impedance value (or optimal capacitor position), that is, a plasma etching process that has been previously executed by the semiconductor process equipment.
  • the corresponding optimal impedance value or optimal capacitor position, which may specifically include the first optimal capacitor position of the first variable capacitor and the second optimal capacitor position of the second variable capacitor
  • the corresponding optimal impedance value or optimal capacitor position
  • the corresponding optimal impedance value or optimal capacitor position
  • the corresponding optimal impedance value can be directly called, and the corresponding optimal impedance value (or optimal capacitor position) can be saved in the preset process parameter list.
  • the plasma etching process to be executed is an existing plasma etching process is determined according to whether the plasma etching process to be executed is stored in the preset process parameter list.
  • the specific process is as follows: whether the plasma etching process to be executed is an existing plasma etching process is determined according to whether the plasma etching process to be executed is stored in the preset process parameter list. If the plasma etching process to be executed is stored in the preset process parameter list, it is determined that the plasma etching process to be executed is an existing plasma etching process. If the plasma etching process to be executed is not stored in the preset process parameter list, it is determined that the plasma etching process to be executed is not an existing plasma etching process.
  • the preset process parameter list may also record in advance the plasma etching process that has not been previously executed by the semiconductor process equipment. At this time, only the plasma etching process that has been executed records the corresponding optimal impedance value (or optimal capacitor position), while the corresponding optimal impedance value (or optimal capacitor position) of the plasma etching process that has not been executed is kept in the default state.
  • the process of judging whether the plasma etching process to be executed is an existing plasma etching process may be specifically as follows: judging whether the plasma etching process to be executed is an existing plasma etching process according to whether the optimal impedance value (or the first optimal capacitor position and the second optimal capacitor position) of the plasma etching process to be executed in the preset process parameter list is in the default state.
  • the optimal impedance value (or the first optimal capacitor position and the second optimal capacitor position) of the plasma etching process to be executed is in the default state, it is determined that the plasma etching process to be executed is not an existing plasma etching process; if the optimal impedance value (or the first optimal capacitor position and the second optimal capacitor position) of the plasma etching process to be executed is not in the default state, it is determined that the plasma etching process to be executed is an existing plasma etching process.
  • Step S112 If the plasma etching process to be performed is not an existing plasma etching process, the optimal impedance value of the variable impedance device is obtained by using the method in the above embodiment, and is recorded and stored in a preset process parameter list.
  • the plasma etching process to be performed is determined by the above method steps, When there is an existing plasma etching process, it means that the semiconductor process equipment has not previously executed the plasma etching process to be executed. At this time, it is necessary to use the method in the above embodiment to search for the optimal impedance value (or optimal capacitance position) of the plasma etching process to be executed, so as to obtain the optimal impedance value of the variable impedance device (or the first optimal capacitance position of the first variable capacitor and the second optimal capacitance position of the second variable capacitor) under the process conditions corresponding to the plasma etching process to be executed, and record and store them in the preset process parameter list to facilitate the direct call of the corresponding optimal impedance value (or optimal capacitance position) when the same process is executed later.
  • Step S113 If the plasma etching process to be performed is an existing plasma etching process, then the plasma etching process to be performed and its corresponding stored optimal impedance value are found in the preset process parameter list.
  • the plasma etching process to be executed is an existing plasma etching process
  • the corresponding optimal impedance value (or optimal capacitance position, which may specifically include the first optimal capacitance position of the first variable capacitor and the second optimal capacitance position of the second variable capacitor) will be pre-recorded in its preset process parameter list. Therefore, when it is determined through the above method steps that the plasma etching process to be executed is an existing plasma etching process, the plasma etching process to be executed and its corresponding stored optimal impedance value (or the first optimal capacitance position and the second optimal capacitance position) can be directly found in the preset process parameter list.
  • the embodiment of the present application also provides a semiconductor process equipment, which includes an RF power supply with a frequency sweeping function, an impedance matcher for adjusting the back-end impedance of the RF power supply in real time, and a controller
  • the impedance matcher includes a variable impedance device for impedance adjustment
  • the controller includes a processor, a memory, and a program stored in the memory and executable on the processor, and when the program is executed by the processor, the steps of the method for obtaining the optimal capacitance position of the impedance matcher in the above embodiment or the steps of the frequency sweeping matching method in the above embodiment are executed, which will not be repeated here.
  • the impedance matcher may be an L-type impedance matcher, a ⁇ -type impedance matcher, Matcher, T-type impedance matcher, L-type impedance matcher consists of a series inductor and a parallel capacitor, and its structure is similar to the letter L.
  • ⁇ -type impedance matcher consists of two parallel capacitors and a series inductor, and its structure is similar to the letter ⁇ .
  • T-type impedance matcher consists of two series inductors and a parallel capacitor, and its structure is similar to the letter T.
  • first and second are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly referring to.
  • the number of technical features indicated by the specification is thus defined as “first” or “second” and may explicitly or implicitly include one or more features.
  • “plurality” means two or more, unless otherwise explicitly and specifically defined.
  • the word "exemplary” is used to mean “used as an example, illustration or description”. Any embodiment described as “exemplary” in this application is not necessarily to be construed as being more preferred or more advantageous than other embodiments.
  • the present application provides the above description.
  • various details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present application can be implemented without using these specific details.
  • well-known structures and processes will not be elaborated in detail to avoid unnecessary details that make the description of the present application obscure. Therefore, the present application is not intended to be limited to the embodiments shown, but is consistent with the widest range of principles and features disclosed in the present application.

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Abstract

本申请公开了一种半导体工艺设备及最优阻抗值获取方法、扫频匹配方法，属于半导体工艺技术。该扫频匹配方法包括以下步骤：根据当前待执行的等离子体刻蚀工艺，获取可变阻抗器件的最优阻抗值；将该可变阻抗器件的阻抗固定在该最优阻抗值；开启射频电源的扫频模式，以实现等离子体起辉匹配。本技术方案，其可有效避免射频电源输出的信号震荡的问题，提高射频电源的扫频匹配成功率，进而提高工艺结果的可重复性和稳定性。

Description

半导体工艺设备及最优阻抗值获取方法、扫频匹配方法 技术领域
本申请属于半导体工艺技术领域，尤其涉及一种半导体工艺设备及最优阻抗值获取方法、扫频匹配方法。
背景技术
在等离子体刻蚀机中，通常由射频电源为自由电子提供电磁场环境，使得自由电子获得更多的能量。根据传输线理论，在射频电源的射频能量传输的过程中，需要实现阻抗匹配，才能保证射频能量最大限度地被等离子体吸收。目前在大部分等离子体刻蚀机中，通常会采用以下三种方式进行阻抗匹配：方式一：在射频电源与等离子体之间加入一个可自动调节的匹配网络，即阻抗匹配器，来实时调节射频电源后端的阻抗。该方式主要存在以下两个缺点：1、匹配时间较长(在0.5s-2s范围内)，这是因为阻抗匹配器是通过步进电机转动实现电容位置的调节，其中步进电机属于机械结构，所以调节速度较慢。2、在相同的气压、功率和气体种类的条件下，重复进行等离子体起辉匹配所需时间相差较多，这是因为每次起辉匹配过程中匹配器存在多条匹配路径，导致匹配时间不一致。方式二：利用具有扫频功能的射频电源，通过自动调节电源输出的中心频率进行阻抗匹配。该方式虽然匹配速度较快，但是由于目前射频电源支持的频带范围较窄(中心频率的频带范围为13.56MHz的±5％)，使得射频电源的扫频能够匹配的阻抗范围很小，不能够完成不同情况下等离子体的起辉匹配任务。方式三：具有扫频功能的射频电源与阻抗匹配器相结合的方式完成阻抗匹配。这种通过具有扫频功能的射频电源和阻抗匹配器相互配合的方式，可快速完成等离子体起辉匹配的过程，且能够完成不同情况下等离子体的起辉匹配任务，因而，在等离子体刻蚀机 的阻抗匹配中得到越来越广泛的应用。
然而，在实际应用过程中发现，上述方式三的阻抗匹配方式容易因为射频电源的负载阻抗不合适而出现射频电源输出的信号震荡的现象，进而导致射频电源的扫频匹配失败，即使得等离子体起辉失败。
发明内容
本申请实施例提供一种半导体工艺设备及最优阻抗值获取方法、扫频匹配方法，旨在解决现有采用具有扫频功能的射频电源与阻抗匹配器相结合的方式完成阻抗匹配的方式容易因为射频电源的负载阻抗不合适而出现射频电源输出的信号震荡的现象，进而导致射频电源的扫频匹配失败的技术问题。
第一方面，本申请实施例提供一种用于获取阻抗匹配器的最优阻抗值的方法，所述阻抗匹配器用于实时调节射频电源后端阻抗，所述阻抗匹配器包括用于进行阻抗调节的可变阻抗器件，所述方法包括以下步骤：
将所述可变阻抗器件的阻抗调整至预设阻抗值；
启动所述射频电源，并在所述射频电源的扫频功能关闭的情形下，利用自动匹配算法调节所述可变阻抗器件的阻抗，以进行阻抗匹配调节；
在完成所述阻抗匹配调节后，记录此时所述可变阻抗器件的匹配阻抗值，并关闭所述射频电源；
将所述可变阻抗器件的阻抗固定在所述匹配阻抗值后，再次开启所述射频电源；
调节所述射频电源的工作频率，获取每次调节所得到的所述射频电源的工作频率与功率反射系数的对应关系，以生成相应的关系曲线；
当所述关系曲线满足预设要求时，将当前的所述匹配阻抗值记录为最优阻抗值。
在一些实施例中，所述调节所述射频电源的工作频率的步骤包括：
在所述射频电源的工作频率区间内，将所述射频电源的工作频率由所述工作频率区间的最小值和最大值中的一者，按第一预设调节步长逐渐修改到所述工作频率区间的最小值和最大值中的另一者。
在一些实施例中，所述预设要求包括所述关系曲线存在所述功率反射系数小于0.01对应的工作频率点和所述关系曲线不存在所述功率反射系数震荡的区域。
在一些实施例中，所述调节所述射频电源的工作频率，获取每次调节所得到的所述射频电源的工作频率与功率反射系数的对应关系，以生成相应的关系曲线的步骤之后，还包括：
当所述关系曲线不满足预设要求时，调整所述匹配阻抗值；
获取每次所述匹配阻抗值调整后，调节所述射频电源的工作频率所生成的关系曲线，直至所获取的所述关系曲线满足预设要求时，将当前的所述匹配阻抗值记录为最优阻抗值。
在一些实施例中，所述可变阻抗器件包括第一可变电容和第二可变电容；
所述将所述可变阻抗器件调整至预设阻抗值的步骤包括：将所述第一可变电容调整至第一预设电容位置，及将所述第二可变电容调整至第二预设电容位置；
所述在完成所述阻抗匹配调节后，记录此时所述可变阻抗器件的匹配阻抗值的步骤包括：在完成所述阻抗匹配调节后，记录此时所述第一可变电容的第一电容位置和所述第二可变电容的第二电容位置；
所述将所述可变阻抗器件的阻抗固定在所述匹配阻抗值的步骤包括：将所述第一可变电容固定在所述第一电容位置，和将所述第二可变电容固定在所述第二电容位置；
所述将当前的所述匹配阻抗值记录为最优阻抗值的步骤包括：将当前的 所述第一电容位置记录为第一最优电容位置，及将当前的所述第二电容位置记录为第二最优电容位置。
在一些实施例中，还包括：
当所述关系曲线不满足预设要求时，按第二预设调节步长逐渐减少所述第一电容位置的当前取值，及按第三预设调节步长逐渐减少所述第二电容位置的当前取值，进而实现所述匹配阻抗值的调整。
在一些实施例中，所述第一可变电容连接在所述射频电源的输出端与地之间，所述第二可变电容连接在所述射频电源的输出端与负载之间；
所述第三预设调节步长大于所述第二预设调节步长。
第二方面，本申请实施例提供一种半导体工艺设备的射频电源扫频匹配方法，所述半导体工艺设备包括具有扫频功能的射频电源以及用于实时调节所述射频电源后端阻抗的阻抗匹配器，所述阻抗匹配器包括用于进行阻抗调节的可变阻抗器件，所述扫频匹配方法包括以下步骤：
根据当前待执行的等离子体刻蚀工艺，利用上述的方法获取所述可变阻抗器件的所述最优阻抗值；
将所述可变阻抗器件的阻抗固定在所述最优阻抗值；
开启所述射频电源的扫频模式，以实现等离子体起辉匹配。
在一些实施例中，所述获取所述可变阻抗器件的所述最优阻抗值的步骤包括：
判断所述待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺；
若所述待执行的等离子体刻蚀工艺不是已有等离子体刻蚀工艺，则获取所述可变阻抗器件的所述最优阻抗值，并记录存储在预设工艺参数列表中。
在一些实施例中，所述判断所述待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺的步骤包括：
根据所述预设工艺参数列表中是否存储有所述待执行的等离子体刻蚀 工艺，来判断所述待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺；
若所述预设工艺参数列表中存储有所述待执行的等离子体刻蚀工艺，则确定所述待执行的等离子体刻蚀工艺是已有等离子体刻蚀工艺；
若所述预设工艺参数列表中未存储有所述待执行的等离子体刻蚀工艺，则确定所述待执行的等离子体刻蚀工艺不是已有等离子体刻蚀工艺。
在一些实施例中，所述判断所述待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺的步骤包括：
根据所述预设工艺参数列表中，所述待执行的等离子体刻蚀工艺的最优阻抗值是否为缺省状态，来判断所述待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺；
若所述待执行的等离子体刻蚀工艺的最优阻抗值是缺省状态，则确定所述待执行的等离子体刻蚀工艺不是已有等离子体刻蚀工艺；
若所述待执行的等离子体刻蚀工艺的最优阻抗值不是缺省状态，则确定所述待执行的等离子体刻蚀工艺是已有等离子体刻蚀工艺。
在一些实施例中，所述获取所述可变阻抗器件的所述最优阻抗值的步骤还包括：
若所述待执行的等离子体刻蚀工艺是已有等离子体刻蚀工艺，则在所述预设工艺参数列表中找出所述待执行的等离子体刻蚀工艺及其对应存储的所述最优阻抗值。
第三方面，本申请实施例提供一种半导体工艺设备，包括具有扫频功能的射频电源、用于实时调节所述射频电源后端阻抗的阻抗匹配器以及控制器，所述阻抗匹配器包括用于进行阻抗调节的可变阻抗器件，所述控制器包括处理器、存储器以及存储在所述存储器上并可在所述处理器上运行的程序，所述程序被所述处理器执行时实现上述用于获取阻抗匹配器的最优阻抗值的方法的步骤或执行上述扫频匹配方法的步骤。
在本申请中，其半导体工艺设备在进行射频电源扫频匹配时，可针对具体的工艺条件(即当前待执行的等离子体刻蚀工艺)，来先找到可变阻抗器件的最优阻抗值，该最优阻抗值可确保射频电源的工作频率与功率反射系数的关系曲线满足预设要求，即找到该射频电源的合适负载，以确保该射频电源扫频时，射频电源的工作频率与功率反射系数的关系曲线满足一一对应的变化关系，这样便可在将该可变阻抗器件的阻抗固定在该最优阻抗值后，开启其射频电源的扫频模式，即在该合适负载处开启电源扫频模式，使等离子体快速起辉，避免出现频率震荡区域，进而实现等离子体起辉匹配。可见，本技术方案，其可有效避免射频电源输出的信号震荡的问题，提高射频电源的扫频匹配成功率，进而提高工艺结果的可重复性和稳定性。
附图说明
下面结合附图，通过对本申请的具体实施方式详细描述，将使本申请的技术方案及其有益效果显而易见。
图1是现有采用具有扫频功能的射频电源与阻抗匹配器相结合的方式完成阻抗匹配的工作原理图。
图2是图1所示的射频电源扫频失败时的射频电源的工作频率与功率反射系数的关系曲线图。
图3是图2所示的射频电源的工作频率与功率反射系数的关系曲线图的局部Ⅰ放大示意图。
图4是图1所示的射频电源的电源负载的工作原理图。
图5是本申请实施例提供的用于获取阻抗匹配器的最优阻抗值的方法的一种流程框图。
图6是本申请实施例提供的用于获取阻抗匹配器的最优阻抗值的方法的另一种流程框图。
图7是本申请实施例提供的半导体工艺设备的扫频匹配方法的流程框图。
图8是图7所示的扫频匹配方法中的射频电源的工作频率与功率反射系数的关系曲线图。
图9是图7所示的扫频匹配方法中L型阻抗匹配器的结构示意图。
图10是图7所示的扫频匹配方法的步骤S110的流程框图。
具体实施方式
下面结合附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅是本申请一部分实施例，而非全部实施例。基于本申请中的实施例，本领域技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。在不冲突的情况下，下述各个实施例及其技术特征可以相互组合。
在一种相关技术中，等离子体刻蚀机会采用具有扫频功能的射频电源与阻抗匹配器相结合的方式完成阻抗匹配，其工作原理如图1所示，通常分为以下两个阶段：第一阶段，将阻抗匹配器的可变电容固定，同时开启射频电源的扫频功能，此时，射频电源的功率检测模块利用检测控制电路，通过高频测量电感检测入射功率和反射功率，经过计算得到功率反射系数Γ，并将该信号提供给频率控制模块，该频率控制模块会以反射系数Γ作为输入变量结合扫频匹配算法，计算出频率调整量，并将频率调整量反馈给射频信号源，实现自动调节射频电源工作频率的阻抗匹配反馈过程，该阶段利用射频电源的扫频功能进行初步匹配，此时线路中反射功率可降为入射功率的5％-10％，帮助等离子体快速起辉。第二阶段，将射频电源的工作频率固定，开启阻抗匹配器的自动调节模式。此时，阻抗匹配器的传感器将检测线路中信号的电压V和电流I，通过数字信号处理可以得到由阻抗匹配器的输入端向阻抗匹 配器的输出端看去的输入阻抗的幅值Mag和相位Phase信息，作为自动匹配算法的输入变量，控制器根据传感器提供的变量结合自动匹配算法，计算给出步进电机的调整量，进而改变可调谐电容器件C1、C2的电容值，经过微调C1和C2的电容位置，将线路中的反射功率降到1％以内，完成最终的匹配。可见，这种通过具有扫频功能的射频电源和阻抗匹配器相互配合的方式，可快速完成等离子体起辉匹配的过程，且能够完成不同情况下等离子体的起辉匹配任务，因而，在等离子体刻蚀机的阻抗匹配中得到越来越广泛的应用。
然而，在实际应用过程中发现，这种阻抗匹配方式仍存在以下问题：在利用射频电源的扫频功能实现等离子体起辉时，由于射频电源是通过判断功率反射系数与工作频率的关系，进行射频电源的输出频率调节，最终找到功率反射系数最低的工作频率点，来完成等离子体起辉匹配过程。所以要想实现快速、稳定的等离子体起辉过程，则在射频电源进行扫频匹配时，需要保证线路中的功率反射系数和射频电源的工作频率是一一对应的变化关系。但在实际阻抗匹配过程中，当射频电源的负载阻抗不合适时，会出现图2及图3所示的射频电源的工作频率(Frequency)与功率反射系数(Γ2)的关系曲线，可以明显地观察到，射频电源的工作频率(Frequency)在13.4MHz-13.5MHz区间内对应的功率反射系数(Γ2)存在震荡，使得射频电源在扫频的过程中，如果射频电源的工作频率落入该区域后，则无法跳出，进而不能将反射功率降到入射功率的5％-10％并固定，这会导致射频电源的扫频匹配失败，即使得等离子体起辉失败。
进一步地，上述射频电源扫频匹配失败的主要原因是，在射频电源的输出端连接不同的负载时，射频电源输出的信号可能存在震荡现象。如图4所示，线路中电压信号由入射电压波Ui(z)和反射电压波Ur(z)组成，其中Ur(z)与负载反射系数ΓL相关，当电源负载ZL不同时，负载反射系数ΓL不同，从而导致在电源功率放大器中MOS管M1处电压波的幅值(U1、U2)有所不同， 此时会触发MOS管M1的过压、过流、耗散保护等，当MOS管M1无法正常工作时，射频电源输出的信号就会出现如图2及图3所示的震荡现象。
U(z)＝Ui(z)+Ur(z)
Ur(z)＝Ui(z)ΓLe-2γz
如图4所示，射频电源的电源负载ZL由两部分组成：第一部分为阻抗匹配器的匹配网络的阻抗ZM，第二部分是等离子体阻抗ZP。一般利用射频电源的扫频功能进行扫频匹配时，将阻抗匹配器的可变电容C1、C2固定在等离子体起辉匹配后的位置(C1_a，C2_a)，但是如果电容位置不合适，此时电源负载ZL可能会导致射频电源输出的信号震荡，最终射频电源扫频匹配失败。
基于此，有必要提供一种新的射频电源扫频匹配方法的解决方案，以解决现有采用具有扫频功能的射频电源与阻抗匹配器相结合的方式完成阻抗匹配的方式容易因为射频电源的负载阻抗不合适而出现射频电源输出的信号震荡的现象，进而导致射频电源的扫频匹配失败的技术问题。
在一个实施例中，如图5所示，本申请实施例提供一种用于获取阻抗匹配器的最优阻抗值的方法，该阻抗匹配器用于实时调节射频电源后端阻抗，以配合该射频电源快速完成半导体工艺设备的等离子体起辉匹配，该阻抗匹配器包括用于进行阻抗调节的可变阻抗器件，该方法具体可包括以下步骤：
步骤S11：将可变阻抗器件的阻抗调整至预设阻抗值。
可以理解的是，本申请实施例获取阻抗匹配器的最优阻抗值的目的主要在于后续为半导体工艺设备的射频电源进行扫频匹配服务，因而，该阻抗匹配器的具体结构可参考图1和图4所示，即该阻抗匹配器会包括用于进行阻抗调节的可变阻抗器件。进一步地，该可变阻抗器件具体可包括第一可变电容C1和第二可变电容C2。此时，获取阻抗匹配器的最优阻抗值应包括获取 第一可变电容C1的第一最优电容位置和获取第二可变电容C2的第二最优电容位置，即当第一可变电容C1处于第一最优电容位置以及第二可变电容C2处于第二最优电容位置时，该阻抗匹配器的可变阻抗器件的阻抗为最优阻抗值。而为了更便捷地找到该可变阻抗器件的最优阻抗值(即第一可变电容C1的第一最优电容位置和第二可变电容C2的第二最优电容位置)，应在开始寻找前，先将该可变阻抗器件的阻抗调整至合理的阻抗值(即将该可变阻抗器件的阻抗调整至预设阻抗值，具体可包括将第一可变电容调整至第一预设电容位置，及将第二可变电容调整至第二预设电容位置，例如(50％，50％)位置处)。
步骤S12：启动射频电源，并在该射频电源的扫频功能关闭的情形下，利用自动匹配算法调节该可变阻抗器件的阻抗，以进行阻抗匹配调节。
可以理解的是，当通过上述方法步骤将该可变阻抗器件的阻抗调整至预设阻抗值(即将该第一可变电容C1调整至第一预设电容位置，及将该第二可变电容C2调整至第二预设电容位置)后，便可启动射频电源，并在该射频电源的扫频功能关闭的情形下，利用自动匹配算法调节该可变阻抗器件的阻抗，以进行阻抗匹配调节，即通过阻抗匹配器本身自带的自动调节模式调整该可变阻抗器件的阻抗(具体为分别调整第一可变电容C1和第二可变电容C2的电容位置，即第一可变电容C1和第二可变电容C2具体电容取值)，来完成阻抗匹配调节。
步骤S13：在完成该阻抗匹配调节后，记录此时该可变阻抗器件的匹配阻抗值，并关闭该射频电源。
可以理解的是，当通过上述方法步骤使得该阻抗匹配器完成相应的阻抗匹配调节后，便可通过系统自动去记录此时该可变阻抗器件的匹配阻抗值(也可进一步记录此时该第一可变电容C1的第一电容位置和该第二可变电容C2的第二电容位置)。同时，由于此时该可变阻抗器件的匹配阻抗值是在该阻抗 匹配器完成阻抗匹配调节后记录得到的，故此时该第一可变电容C1的第一电容位置具体可与相关技术中第一可变电容C1的匹配位置C1_a重合，该第二可变电容C2的第二电容位置具体可与相关技术中第二可变电容C2的匹配位置C2_a重合。
步骤S14：将该可变阻抗器件的阻抗固定在该匹配阻抗值后，再次开启该射频电源。
可以理解的是，当通过上述方法步骤得到该可变阻抗器件的匹配阻抗值(或者该第一可变电容C1的第一电容位置和该第二可变电容C2的第二电容位置)后，便可通过将可变阻抗器件的阻抗固定在该匹配阻抗值(具体可为将该第一可变电容C1固定在该第一电容位置以及将该第二可变电容C2固定在该第二电容位置)后，再次开启该射频电源，以为后续获取当前匹配阻抗值下，射频电源的工作频率与功率反射系数的关系曲线，做好相应的前期准备。
步骤S15：调节该射频电源的工作频率，获取每次调节所得到的射频电源的工作频率与功率反射系数的对应关系，以生成相应的关系曲线。
可以理解的是，当通过上述方法步骤将可变阻抗器件的阻抗固定在该匹配阻抗值(具体可为将该第一可变电容固定在该第一电容位置以及将该第二可变电容固定在该第二电容位置)，并再次开启射频电源后，便可通过调节该射频电源的工作频率，获取每次调节所得到的射频电源的工作频率与功率反射系数的对应关系，以生成相应的关系曲线。即每调节改变一次该射频电源的工作频率，便可记录一次当前该射频电源的工作频率下对应的功率反射系数，进而在多次调节记录下，获取每次调节所得到的射频电源的工作频率与功率反射系数的对应关系，以生成相应的关系曲线，即当前匹配阻抗值(或者当前的第一电容位置和第二电容位置)下，射频电源的工作频率与功率反射系数的关系曲线。
步骤S16：当该关系曲线满足预设要求时，将当前的该匹配阻抗值记录为最优阻抗值。
可以理解的是，当通过上述方法步骤得到当前匹配阻抗值(或者当前第一电容位置和第二电容位置)下，该射频电源的工作频率与功率反射系数的关系曲线后，便可进一步判断该射频电源的工作频率与功率反射系数的关系曲线是否满足预设要求，以在该关系曲线满足预设要求时，将当前的该匹配阻抗值记录为最优阻抗值(或者将当前的第一电容位置记录为第一最优电容位置，及将当前的第二电容位置记录为第二最优电容位置)。
一般而言，该预设要求具体可包括该关系曲线存在功率反射系数小于0.01对应的工作频率点和该关系曲线不存在功率反射系数震荡的区域，其中，该关系曲线存在功率反射系数小于0.01对应的工作频率点，可确保其存在等离子体起辉匹配的频率点，使得等离子体可成功起辉匹配。而该关系曲线不存在功率反射系数震荡的区域则可确保该射频电源的工作频率与功率反射系数的关系曲线满足一一对应的变化关系，同样可确保等离子体成功起辉匹配。
这样一来，通过本申请实施例的方法获取阻抗匹配器的最优阻抗值(或者获取第一可变电容C1的第一最优电容位置和获取第二可变电容C2的第二最优电容位置)，可确保当阻抗匹配器的用于进行阻抗调节的可变阻抗器件的阻抗固设在该最优阻抗值后，对相应的射频电源进行扫频时，该射频电源的工作频率与功率反射系数的关系曲线可满足一一对应的变化关系，进而可确保等离子体成功起辉匹配。
在一些示例中，为更好地获取当前匹配阻抗值(或者当前的第一电容位置和第二电容位置)下，射频电源的工作频率与功率反射系数的关系曲线，执行上述方法步骤“调节射频电源的工作频率”的过程具体如下：在该射频电源的工作频率区间内，将该射频电源的工作频率由工作频率区间的最小值和最大值中的一者，按第一预设调节步长逐渐修改到工作频率区间的最小值 和最大值中的另一者。具体以该射频电源的工作频率区间为13.56MHz±5％，该第一预设调节步长为0.1MHz为例，此时，将射频电源的工作频率由12.882MHz，按0.1MHz的步长逐渐修改到14.238MHz，并记录每一射频电源的工作频率下对应的功率反射系数，以得到当前匹配阻抗值(即将该第一可变电容固定在该第一电容位置和将该第二可变电容固定在该第二电容位置后对应的匹配阻抗值和电源负载下)下，该射频电源的工作频率与功率反射系数的关系曲线。
一般而言，通过上面的方法步骤第一次找到的该可变阻抗器件的匹配阻抗值是在该阻抗匹配器完成阻抗匹配调节后记录得到的，故此时，该可变阻抗器件的匹配阻抗值亦为相关技术的匹配阻抗值，即此时，该第一可变电容C1的第一电容位置具体可与相关技术中第一可变电容C1的匹配位置C1_a重合，该第二可变电容C2的第二电容位置具体可与相关技术中第二可变电容C2的匹配位置C2_a重合。而基于前面表述可知，相关技术中采用具有扫频功能的射频电源与阻抗匹配器相结合的方式完成阻抗匹配的方式，则是在射频电源进行扫频匹配时，将阻抗匹配器的可变阻抗器件的阻抗固定在匹配阻抗值(即第一可变电容C1和第二可变电容C2固定在匹配位置C1_a和C2_a处)，此时如果电源负载不合适，会出现图2及图3所示的射频电源的工作频率(Frequency)与功率反射系数(Γ2)的关系曲线，可以明显地观察到，射频电源的工作频率(Frequency)在13.4MHz-13.5MHz区间内对应的功率反射系数(Γ2)存在震荡，当射频电源在扫频时，其工作频率进入该震荡区域后，无法跳出并寻找功率反射系数小于0.1的工作频率点，而导致射频电源的扫频匹配失败。特别是一些电负性气体(HBr、CF4等)，存在较大的容性放电到感性放电模式转变的区域，在该区域内等离子体阻抗不稳定，如果此时的匹配阻抗值(即电容位置C1_a和C2_a)不合适，会更容易出现功率反射系数震荡的问题。正是因为在使用相关技术的匹配方式时，没有对射频电 源扫频匹配时的阻抗匹配器的电容固定位置进行优化，提前得到射频电源的工作频率和线路中功率反射系数的关系曲线，所以无法保证射频电源的扫频匹配成功。而本申请实施例的“获取并寻找可变阻抗器件的最优阻抗值(即第一可变电容C1和第二可变电容C2的合适的固定位置处)的电源频率和功率反射系数的关系曲线”这一工作正是相关技术的方案所缺少的部分，也就是相关技术的方案电源扫频失败的根本原因，如果不进行这一步工作，在开启射频电源的扫频功能后，无法保证每次射频电源的扫频都会匹配成功。
因而，在一些示例中，如图6所示，执行上述方法步骤“调节该射频电源的工作频率，获取每次调节所得到的射频电源的工作频率与功率反射系数的对应关系，以生成相应的关系曲线”的步骤之后，还包括：
步骤S17：当该关系曲线不满足预设要求时，调整该匹配阻抗值。
可以理解的是，当通过上述方法步骤的判断，得出当前匹配阻抗值(或者当前第一电容位置和第二电容位置)下，该射频电源的工作频率与功率反射系数的关系曲线不满足上述方法步骤的预设要求时，则说明当前找到的匹配阻抗值(或者第一电容位置和第二电容位置)不可确保等离子体成功起辉匹配，即当前找到的匹配阻抗值非可变阻抗器件的最优阻抗值(或者第一电容位置和第二电容位置非该第一可变电容的第一最优电容位置和该第二可变电容的第二最优电容位置)，此时，需对该匹配阻抗值(或该第一电容位置和该第二电容位置)进行进一步优化，即需进一步调整该匹配阻抗值(或者该第一电容位置和该第二电容位置)，来逐步找出该可变阻抗器件的最优阻抗值(或者该第一可变电容的第一最优电容位置和该第二可变电容的第二最优电容位置)。
步骤S18：获取每次匹配阻抗值调整后，调节该射频电源的工作频率所生成的关系曲线，直至所获取的关系曲线满足预设要求时，将当前的匹配阻抗值记录为最优阻抗值。
可以理解的是，为在调整该匹配阻抗值(或者第一电容位置和第二电容位置)的过程中，逐步找出该可变阻抗器件的最优阻抗值(或者该第一可变电容的第一最优电容位置和该第二可变电容的第二最优电容位置)。需在每调整一次该匹配阻抗值(或者第一电容位置和第二电容位置)后，进行一次调节该射频电源的工作频率，得到相应的关系曲线的过程，即按上述步骤S15的过程得到当前匹配阻抗值(或者当前第一电容位置和第二电容位置)下对应的该射频电源的工作频率与功率反射系数的关系曲线，且每获取得到一个关系曲线，均需进行上述方法步骤中的该关系曲线是否满足预设要求的判断，直至所获取的关系曲线满足预设要求时，将当前的该匹配阻抗值记录为最优阻抗值(或者将当前的第一电容位置记录为第一最优电容位置，及将当前的第二电容位置记录为第二最优电容位置)。
这样一来，通过本申请实施例的方法获取阻抗匹配器的最优阻抗值(或者获取第一可变电容C1的第一最优电容位置和获取第二可变电容C2的第二最优电容位置)，可确保当阻抗匹配器的用于进行阻抗调节的可变阻抗器件的阻抗固设在该最优阻抗值后，对相应的射频电源进行扫频时，该射频电源的工作频率与功率反射系数的关系曲线可满足一一对应的变化关系，进而可确保等离子体成功起辉匹配。
在一些示例中，为更好地通过对第一电容位置和第二电容位置的调整，来实现该匹配阻抗值的调整，可按第二预设调节步长逐渐减少该第一电容位置的当前取值，及按第三预设调节步长逐渐减少该第二电容位置的当前取值。以该第一电容位置的当前取值为匹配位置C1_a，该第二电容位置的当前取值为匹配位置C2_a，第二预设调节步长为1％，第二预设调节步长为2％为例，需在电容匹配位置C1_a和C2_a的基础上分别以1％、2％为步长逐步减小电容位置，以获取每次电容位置调整(即匹配阻抗值调整)后，调节该射频电源的工作频率所生成的关系曲线，直至所获取的关系曲线满足预设要求时， 将当前的第一电容位置记录为第一最优电容位置，及将当前的第二电容位置记录为第二最优电容位置(或者将当前的匹配阻抗值记录为最优阻抗值)。
在一个实施例中，如图7所示，本申请实施例提供一种半导体工艺设备的扫频匹配方法，该半导体工艺设备具体可包括具有扫频功能的射频电源以及用于实时调节射频电源后端阻抗的阻抗匹配器，阻抗匹配器包括用于进行阻抗调节的可变阻抗器件，该扫频匹配方法具体包括以下步骤：
步骤S110：根据当前待执行的等离子体刻蚀工艺，利用上述实施例提供的方法，获取该可变阻抗器件的最优阻抗值。
可以理解的是，本申请实施例的扫频匹配方法是基于相关技术的采用具有扫频功能的射频电源与阻抗匹配器相结合的方式完成阻抗匹配的方式作出的进一步改进，因而，其射频电源和阻抗匹配器的具体结构可参考图1所示，而为了避免出现因为射频电源的负载阻抗不合适而出现射频电源输出的信号震荡的现象，进而导致射频电源的扫频匹配失败的问题。其在进行射频电源的扫频操作前，先找到当前待执行的等离子体刻蚀工艺下，该射频电源的合适负载，即获取该可变阻抗器件的最优阻抗值(或者该第一可变电容C1的第一最优电容位置以及该第二可变电容C2的第二最优电容位置)，以确保该射频电源扫频时，该射频电源的工作频率与功率反射系数的关系曲线满足图8所示的一一对应的变化关系。
步骤S120：将该可变阻抗器件的阻抗固定在该最优阻抗值。
可以理解的是，当通过上述方法步骤获取得到该可变阻抗器件的最优阻抗值(或者该第一可变电容C1的第一最优电容位置以及该第二可变电容C2的第二最优电容位置)后，便可进一步将该可变阻抗器件的阻抗固定在该最优阻抗值(具体可为将该第一可变电容固定在该第一最优电容位置以及将该第二可变电容固定在该第二最优电容位置)，此时，即可使得射频电源具有合适的负载。
步骤S130：开启该射频电源的扫频模式，以实现等离子体起辉匹配。
可以理解的是，当通过上述方法步骤将该可变阻抗器件的阻抗固定在该最优阻抗值(或者该第一可变电容C1的第一最优电容位置以及该第二可变电容C2的第二最优电容位置)，即使得射频电源具有合适的负载后，开启该射频电源的扫频模式，即可通过在该合适负载处开启电源扫频模式，来使等离子体快速起辉，避免出现频率震荡区域，进而实现等离子体稳定且可重复的起辉匹配过程。
进一步的，基于上述表述可知，当寻找得到该可变阻抗器件的最优阻抗值(或者该第一可变电容C1的第一最优电容位置以及该第二可变电容C2的第二最优电容位置)后，开启该射频电源的扫频功能时，可帮助等离子体快速起辉匹配。目前常用的L型阻抗匹配器如图9所示，第一可变电容C1连接在射频电源的输出端与地之间，第二可变电容C2连接在射频电源的输出端与负载(即图9中所示的等离子体部分)之间。
在射频电源的输出端向等离子体看去的输入导纳为GL
记则输入导纳GL的实部和虚部为

根据输入导纳的实部和虚部表达式可发现，第一可变电容C1只影响输入导纳的虚部，第二可变电容C2不仅会影响输入导纳的实部还影响输入导纳的虚部。当第一可变电容C1和第二可变电容C2分别固定到匹配位置，射频电源的工作频率和功率反射系数曲线不满足要求时，主要是因为此时电源 负载ZL不合适，其中，ZL包含阻抗匹配器的匹配网络的阻抗ZM和等离子体的阻抗ZP两部分，目前无法改变等离子体的阻抗ZP，只能通过修改匹配网络的阻抗ZM，得到合适的电源负载ZL，同时在等离子体起辉之前刻蚀机腔室的阻抗值偏大，所以可同时将C2位置降低2％，将C1位置降低1％，即使得上文提到的第三预设调节步长大于第二预设调节步长，以快速增加匹配网络对应的阻抗值后，再重复进行寻找电容位置的过程。根据本申请实施例进行最优电容位置寻找之后，可最终得到如图8所示的该射频电源的工作频率与功率反射系数的关系曲线。
这样一来，在本申请实施例中，其可有效避免射频电源输出的信号震荡的问题，提高射频电源的扫频匹配成功率，进而提高工艺结果的可重复性和稳定性。
在一些示例中，如图10所示，为更好地获取该可变阻抗器件的最优阻抗值(或者相应的第一可变电容的第一最优电容位置以及相应的第二可变电容的第二最优电容位置)，执行上述方法步骤“根据当前待执行的等离子体刻蚀工艺，利用上述实施例提供的方法，获取该可变阻抗器件的最优阻抗值”的具体过程如下：
步骤S111：判断待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺。
可以理解的是，已有等离子体刻蚀工艺一般指已自动寻找并保存最优阻抗值(或者最优电容位置)的等离子体刻蚀工艺，即该半导体工艺设备先前已执行过的等离子体刻蚀工艺，该工艺在先前执行过程中，已找到相应的最优阻抗值(或者最优电容位置，具体可包括该第一可变电容的第一最优电容位置以及该第二可变电容的第二最优电容位置)，及为便于后续执行相同的该工艺时，可直接调用相应的最优阻抗值(或者最优电容位置)，其可将相应的最优阻抗值(或者最优电容位置)保存至预设工艺参数列表中。因而，可根 据预设工艺参数列表中是否存有该待执行的等离子体刻蚀工艺，来判断该待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺，其过程具体如下：根据该预设工艺参数列表中是否存储有该待执行的等离子体刻蚀工艺，来判断该待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺。若该预设工艺参数列表中存储有该待执行的等离子体刻蚀工艺，则确定该待执行的等离子体刻蚀工艺是已有等离子体刻蚀工艺。若该预设工艺参数列表中未存储有该待执行的等离子体刻蚀工艺，则确定待执行的等离子体刻蚀工艺不是已有等离子体刻蚀工艺。
另外，该预设工艺参数列表中也可提前记录该半导体工艺设备先前未执行过的等离子体刻蚀工艺，此时，仅执行过的等离子体刻蚀工艺记录有相应的最优阻抗值(或者最优电容位置)，而未执行过的等离子体刻蚀工艺的记录相应的最优阻抗值(或者最优电容位置)处保持缺省状态，此时，判断待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺的过程可具体如下：根据该预设工艺参数列表中，该待执行的等离子体刻蚀工艺的最优阻抗值(或者第一最优电容位置以及第二最优电容位置)是否为缺省状态，来判断该待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺。若该待执行的等离子体刻蚀工艺的最优阻抗值(或者第一最优电容位置以及第二最优电容位置)是缺省状态，则确定该待执行的等离子体刻蚀工艺不是已有等离子体刻蚀工艺；若该待执行的等离子体刻蚀工艺的最优阻抗值(或者第一最优电容位置以及第二最优电容位置)不是缺省状态，则确定该待执行的等离子体刻蚀工艺是已有等离子体刻蚀工艺。
步骤S112：若该待执行的等离子体刻蚀工艺不是已有等离子体刻蚀工艺，则利用上述实施例中的方法获取该可变阻抗器件的最优阻抗值，并记录存储在预设工艺参数列表中。
可以理解的是，当通过上述方法步骤确定待执行的等离子体刻蚀工艺不 是已有等离子体刻蚀工艺时，则说明该半导体工艺设备先前未执行过当前待执行的等离子体刻蚀工艺，此时，需通过上述实施例中的方法对待执行的等离子体刻蚀工艺进行最优阻抗值(或者最优电容位置)寻找处理，以获取在待执行的等离子体刻蚀工艺对应的工艺条件下，该可变阻抗器件的最优阻抗值(或者第一可变电容的第一最优电容位置和第二可变电容的第二最优电容位置)，并记录存储在预设工艺参数列表中，以方便后续执行相同的该工艺时，可直接调用相应的最优阻抗值(或者最优电容位置)。
步骤S113：若待执行的等离子体刻蚀工艺是已有等离子体刻蚀工艺，则在预设工艺参数列表中找出待执行的等离子体刻蚀工艺及其对应存储的最优阻抗值。
可以理解的是，基于上述表述可知，当该待执行的等离子体刻蚀工艺是已有等离子体刻蚀工艺时，其预设工艺参数列表中会预先记录有相应的最优阻抗值(或者最优电容位置，具体可包括该第一可变电容的第一最优电容位置以及该第二可变电容的第二最优电容位置)，因而，当通过上述方法步骤判断待执行的等离子体刻蚀工艺是已有等离子体刻蚀工艺时，则可在预设工艺参数列表中直接找出待执行的等离子体刻蚀工艺及其对应存储的最优阻抗值(或者第一最优电容位置和第二最优电容位置)。
在一个实施例中，本申请实施例还提供一种半导体工艺设备，该半导体工艺设备包括具有扫频功能的射频电源、用于实时调节射频电源后端阻抗的阻抗匹配器以及控制器，阻抗匹配器包括用于进行阻抗调节的可变阻抗器件，控制器包括处理器、存储器以及存储在该存储器上并可在该处理器上运行的程序，该程序被该处理器执行时执行上述实施例中的用于获取阻抗匹配器的最优电容位置的方法的步骤或上述实施例中的扫频匹配方法的步骤，此处不再赘述。
在一些示例中，上述阻抗匹配器具体可以是L型阻抗匹配器、π型阻抗 匹配器、T型阻抗匹配器，L型阻抗匹配器由一个串联电感和并联电容组成，其结构类似于字母L。π型阻抗匹配器由两个并联电容和一个串联电感组成，其结构类似于字母π。T型阻抗匹配器则由两个串联电感和一个并联电容组成，其结构类似于字母T。这些结构形式都可以用来匹配不同的阻抗，且均具有用于进行阻抗调节的第一可变电容和第二可变电容，具体使用哪种结构可根据实际情况来确定。
尽管已经相对于一个或多个实现方式示出并描述了本申请，但是本领域技术人员基于对本说明书和附图的阅读和理解将会想到等价变型和修改。本申请包括所有这样的修改和变型，并且仅由所附权利要求的范围限制。特别地关于由上述组件执行的各种功能，用于描述这样的组件的术语旨在对应于执行所述组件的指定功能(例如其在功能上是等价的)的任意组件(除非另外指示)，即使在结构上与执行本文所示的本说明书的示范性实现方式中的功能的公开结构不等同。
即，以上所述仅为本申请的实施例，并非因此限制本申请的专利范围，凡是利用本申请说明书及附图内容所作的等效结构或等效流程变换，例如各实施例之间技术特征的相互结合，或直接或间接运用在其他相关的技术领域，均同理包括在本申请的专利保护范围内。
另外，在本申请的描述中，需要理解的是，术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。另外，对于特性相同或相似的结构元件，本申请可采用相同或者不相同的标号进行标识。此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指 明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多个特征。在本申请的描述中，“多个”的含义是两个或两个以上，除非另有明确具体的限定。
在本申请中，“示例性”一词是用来表示“用作例子、例证或说明”。本申请中被描述为“示例性”的任何一个实施例不一定被解释为比其它实施例更加优选或更加具优势。为了使本领域任何技术人员能够实现和使用本申请，本申请给出了以上描述。在以上描述中，为了解释的目的而列出了各个细节。应当明白的是，本领域普通技术人员可以认识到，在不使用这些特定细节的情况下也可以实现本申请。在其它实施例中，不会对公知的结构和过程进行详细阐述，以避免不必要的细节使本申请的描述变得晦涩。因此，本申请并非旨在限于所示的实施例，而是与符合本申请所公开的原理和特征的最广范围相一致。

Claims (13)

  1. 一种用于获取阻抗匹配器的最优阻抗值的方法，所述阻抗匹配器用于实时调节射频电源后端阻抗，所述阻抗匹配器包括用于进行阻抗调节的可变阻抗器件，其特征在于，所述方法包括以下步骤：
    将所述可变阻抗器件的阻抗调整至预设阻抗值；
    启动所述射频电源，并在所述射频电源的扫频功能关闭的情形下，利用自动匹配算法调节所述可变阻抗器件的阻抗，以进行阻抗匹配调节；
    在完成所述阻抗匹配调节后，记录此时所述可变阻抗器件的匹配阻抗值，并关闭所述射频电源；
    将所述可变阻抗器件的阻抗固定在所述匹配阻抗值后，再次开启所述射频电源；
    调节所述射频电源的工作频率，获取每次调节所得到的所述射频电源的工作频率与功率反射系数的对应关系，以生成相应的关系曲线；
    当所述关系曲线满足预设要求时，将当前的所述匹配阻抗值记录为最优阻抗值。
  2. 根据权利要求1所述的方法，其特征在于，所述调节所述射频电源的工作频率的步骤包括：
    在所述射频电源的工作频率区间内，将所述射频电源的工作频率由所述工作频率区间的最小值和最大值中的一者，按第一预设调节步长逐渐修改到所述工作频率区间的最小值和最大值中的另一者。
  3. 根据权利要求1所述的方法，其特征在于，所述预设要求包括所述关系曲线存在所述功率反射系数小于0.01对应的工作频率点和所述关系曲线不存在所述功率反射系数震荡的区域。
  4. 根据权利要求1所述的方法，其特征在于，所述调节所述射频电源的工作频率，获取每次调节所得到的所述射频电源的工作频率与功率反射系数的对应关系，以生成相应的关系曲线的步骤之后，还包括：
    当所述关系曲线不满足预设要求时，调整所述匹配阻抗值；
    获取每次所述匹配阻抗值调整后，调节所述射频电源的工作频率所生成的关系曲线，直至所获取的所述关系曲线满足预设要求时，将当前的所述匹配阻抗值记录为最优阻抗值。
  5. 根据权利要求1-4任一项所述的方法，其特征在于，所述可变阻抗器件包括第一可变电容和第二可变电容；
    所述将所述可变阻抗器件调整至预设阻抗值的步骤包括：将所述第一可变电容调整至第一预设电容位置，及将所述第二可变电容调整至第二预设电容位置；
    所述在完成所述阻抗匹配调节后，记录此时所述可变阻抗器件的匹配阻抗值的步骤包括：在完成所述阻抗匹配调节后，记录此时所述第一可变电容的第一电容位置和所述第二可变电容的第二电容位置；
    所述将所述可变阻抗器件的阻抗固定在所述匹配阻抗值的步骤包括：将所述第一可变电容固定在所述第一电容位置，和将所述第二可变电容固定在所述第二电容位置；
    所述将当前的所述匹配阻抗值记录为最优阻抗值的步骤包括：将当前的所述第一电容位置记录为第一最优电容位置，及将当前的所述第二电容位置记录为第二最优电容位置。
  6. 根据权利要求5所述的方法，其特征在于，还包括：
    当所述关系曲线不满足预设要求时，按第二预设调节步长逐渐减少所述第一电容位置的当前取值，及按第三预设调节步长逐渐减少所述第二电容位 置的当前取值，进而实现所述匹配阻抗值的调整。
  7. 根据权利要求6所述的方法，其特征在于，所述第一可变电容连接在所述射频电源的输出端与地之间，所述第二可变电容连接在所述射频电源的输出端与负载之间；
    所述第三预设调节步长大于所述第二预设调节步长。
  8. 一种半导体工艺设备的扫频匹配方法，所述半导体工艺设备包括具有扫频功能的射频电源以及用于实时调节所述射频电源后端阻抗的阻抗匹配器，所述阻抗匹配器包括用于进行阻抗调节的可变阻抗器件，其特征在于，所述扫频匹配方法包括以下步骤：
    根据当前待执行的等离子体刻蚀工艺，利用如权利要求1-7任一项所述的方法获取所述可变阻抗器件的所述最优阻抗值；
    将所述可变阻抗器件的阻抗固定在所述最优阻抗值；
    开启所述射频电源的扫频模式，以实现等离子体起辉匹配。
  9. 根据权利要求8所述的扫频匹配方法，其特征在于，所述获取所述可变阻抗器件的所述最优阻抗值的步骤包括：
    判断所述待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺；
    若所述待执行的等离子体刻蚀工艺不是已有等离子体刻蚀工艺，则获取所述可变阻抗器件的所述最优阻抗值，并记录存储在预设工艺参数列表中。
  10. 根据权利要求9所述的扫频匹配方法，其特征在于，所述判断所述待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺的步骤包括：
    根据所述预设工艺参数列表中是否存储有所述待执行的等离子体刻蚀工艺，来判断所述待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺；
    若所述预设工艺参数列表中存储有所述待执行的等离子体刻蚀工艺，则确定所述待执行的等离子体刻蚀工艺是已有等离子体刻蚀工艺；
    若所述预设工艺参数列表中未存储有所述待执行的等离子体刻蚀工艺，则确定所述待执行的等离子体刻蚀工艺不是已有等离子体刻蚀工艺。
  11. 根据权利要求9所述的扫频匹配方法，其特征在于，所述判断所述待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺的步骤包括：
    根据所述预设工艺参数列表中，所述待执行的等离子体刻蚀工艺的最优阻抗值是否为缺省状态，来判断所述待执行的等离子体刻蚀工艺是否为已有等离子体刻蚀工艺；
    若所述待执行的等离子体刻蚀工艺的最优阻抗值是缺省状态，则确定所述待执行的等离子体刻蚀工艺不是已有等离子体刻蚀工艺；
    若所述待执行的等离子体刻蚀工艺的最优阻抗值不是缺省状态，则确定所述待执行的等离子体刻蚀工艺是已有等离子体刻蚀工艺。
  12. 根据权利要求9-11任一项所述的扫频匹配方法，其特征在于，所述获取所述可变阻抗器件的所述最优阻抗值的步骤还包括：
    若所述待执行的等离子体刻蚀工艺是已有等离子体刻蚀工艺，则在所述预设工艺参数列表中找出所述待执行的等离子体刻蚀工艺及其对应存储的所述最优阻抗值。
  13. 一种半导体工艺设备，其特征在于，包括具有扫频功能的射频电源、用于实时调节所述射频电源后端阻抗的阻抗匹配器以及控制器，所述阻抗匹配器包括用于进行阻抗调节的可变阻抗器件，所述控制器包括处理器、存储器以及存储在所述存储器上并可在所述处理器上运行的程序，所述程序被所述处理器执行时实现如权利要求1-7任一所述的方法的步骤或执行如权利要求8-12任一项所述的扫频匹配方法的步骤。
PCT/CN2024/101805 2023-06-30 2024-06-27 半导体工艺设备及最优阻抗值获取方法、扫频匹配方法 Ceased WO2025002211A1 (zh)

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