A method and system for impedance matching based on a matrix matching graph

Abstract

The present invention relates to the field of semiconductor technology, and more particularly, to a method and system for impedance matching based on a matrix matching graph. The method of the present invention includes the following steps: starting a radio frequency power supply and setting a matching value as an initial point; configuring a matrix with the initial point as the scanning starting point; starting a matrix scanning operation to record the corresponding reflected power and output frequency values as the element values of the corresponding matrix positions; generating a matrix matching graph based on all the matrix element value data; judging each element value data, and if the condition is satisfied, using the current element value data as a preselected matching value; judging each preselected matching value, and if the best matching condition is satisfied, using the current preselected matching value as the best matching value. The present invention accurately identifies the best matching parameters of an impedance matcher through a matrix scanning method, adapts to impedance changes under different process conditions, and significantly improves the stability and reliability of the semiconductor process.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and more particularly to a method and system for impedance matching based on a matrix matching diagram. Background Art

[0002] In a plasma deposition system, the RF power source transmits RF energy from the power source to the reaction chamber (i.e., the load), exciting the reaction gas to form a plasma rich in active particles. The plasma contains a large number of active particles such as electrons, ions, excited atoms, molecules, and free radicals. These active particles interact with the workpiece to be processed / treated (e.g., wafers) placed in the chamber and exposed to the plasma environment, causing various physical and chemical reactions on the surface of the workpiece to be processed / treated, thereby changing the surface properties of the workpiece, thereby completing plasma etching, deposition, or other process.

[0003] During the RF energy transmission process, the output impedance of the RF power supply is usually 50 ohms, while the equivalent impedance of the plasma reaction chamber is usually not 50 ohms, and the equivalent impedance of the plasma reaction chamber will also change under different process conditions. When the output impedance of the RF power supply does not match the load impedance, the output power of the RF power supply will be lost, and a large amount of reflected power will be generated on the transmission line, which will cause the plasma to be unable to obtain sufficient energy and thus difficult to ignite, and unable to complete the predetermined plasma process, and may even damage the RF power supply, causing local overheating, and even fire and other safety issues in severe cases.

[0004] In order to solve this problem, an impedance matcher that can automatically adjust the load impedance needs to be installed between the RF power supply and the plasma reaction chamber so that the load impedance is matched to 50 ohms, thereby ensuring the effective transmission of RF energy.

[0005] The impedance matching method in the prior art is to add a matching device that automatically adjusts the impedance between the RF power supply and the reaction chamber. Inside the matching device, the sensor monitors the impedance value in the circuit in real time. When the energy of the RF power supply is transmitted to the matching device, the matching device controls the capacitance value of the adjustable capacitor through a preset algorithm based on the real-time impedance value fed back by the sensor, thereby adjusting the impedance of the matching device and the impedance of the plasma reaction chamber to 50 ohms, completing the impedance matching.

[0006] The advantage of this matching method is that it can automatically achieve impedance matching between the RF power supply and the reaction chamber, so that the impedance value is stabilized at 50 ohms. In the early stage of the process, after the matcher finds the appropriate capacitance parameters through the automatic mode, it will switch to the fixed mode (Fix mode) to ensure the stability of the process and improve production efficiency.

[0007] However, the effect of this matching method is closely related to the initial capacitance value of the tunable capacitor. Since the lossy devices in the plasma reaction chamber will gradually consume with use, the impedance of the chamber will change continuously under the same process conditions. Therefore, if the initial capacitance value of the tunable capacitor remains unchanged, it may lead to a gradual loss of consistency in the impedance matching process, thereby reducing the matching efficiency.

[0008] To solve these problems, further optimizing the impedance matching method to improve process adaptability and matching efficiency has become a technical difficulty that urgently needs to be broken through. Summary of the Invention

[0009] The object of the present invention is to provide a method and system for impedance matching based on a matrix matching diagram, which solves the problems of decreased matching efficiency and unstable energy transmission caused by impedance value changes in existing plasma processing equipment.

[0010] To achieve the above object, the present invention provides a method for impedance matching based on a matrix matching diagram, which uses a matcher to adjust the impedance matching between the RF power supply and the cavity load in the plasma processing equipment. The matcher includes at least a first tunable capacitor and a second tunable capacitor;

[0011] The method includes the following steps:

[0012] Start the RF power supply and set a matching value as the initial point. The matching value is a set of first tunable capacitor parameters and second tunable capacitor parameters;

[0013] Configure a matrix with the initial point as the scanning starting point. The rows and columns of the matrix are respectively composed of the first tunable capacitor parameters and the second tunable capacitor parameters;

[0014] Start the matrix scanning operation, sequentially change the values of the first tunable capacitor parameters and / or the second tunable capacitor parameters in the matrix, and record the corresponding reflected power and output frequency values as the element values of the corresponding matrix positions;

[0015] Generate a matrix matching diagram based on all the matrix element value data;

[0016] Judge whether each element value data in the matrix matching diagram meets a preset judgment condition. If it meets the preset judgment condition, use the current element value data as the preselected matching value. If it does not meet the preset judgment condition, reset the initial point and start the matrix scanning. The preset judgment condition is related to the reflected power value and the output frequency value;

[0017] Generate a set of preselected matching values from all the preselected matching values;

[0018] For each preselected matching value in the set of preselected matching values, determine whether it meets the best matching condition. If it meets the best matching condition, use the current preselected matching value as the best matching value. If it does not meet the best matching condition, reset the initial point and start matrix scanning, and repeat the above steps;

[0019] The best matching condition is related to the element value data around the preselected matching value.

[0020] In some embodiments, the preset determination condition at least includes: the reflected power is equal to 0 and the absolute value of the difference between the output frequency value and the preset target frequency value is the smallest;

[0021] The step of determining whether each element value data in the matrix matching graph meets the preset determination condition includes:

[0022] If the current element value data meets the condition that the reflected power is equal to 0 and the absolute value of the difference between the output frequency value and the preset target frequency value is the smallest, use the current element value data as the preselected matching value.

[0023] In some embodiments, the preset determination condition at least includes a first determination condition and a second determination condition:

[0024] The first determination condition is that the reflected power is equal to 0, and the difference between the output frequency and the preset target frequency value is within the first preset frequency threshold range;

[0025] The second determination condition is that the reflected power is equal to 0, and the absolute value of the difference between the output frequency value and the preset target frequency value is the smallest;

[0026] The step of determining whether each element value data in the matrix matching graph meets the preset determination condition includes:

[0027] Determine whether each element value data in the matrix matching graph meets the first determination condition, select the element value data that meets the first determination condition as the first determination matching value, and generate a set of first determination matching values from all the first determination matching values;

[0028] Determine whether each element value data in the set of first determination matching values meets the second determination condition, and select the element value data that meets the second determination condition as the preselected matching value.

[0029] In some embodiments, the best matching condition is:

[0030] Taking the current preselected matching value as the center point, determine that the matrix element values within the specified range around the center point all meet the condition that the reflected power is equal to 0, and the difference between the output frequency and the preset target frequency value is within the second preset frequency threshold range.

[0031] In some embodiments, a specified range around the center point forms a matrix composed of matrix element values of an N-row by N-column matrix, where N is greater than or equal to 3.

[0032] In some embodiments, the initial point is the matching value obtained by switching the matcher to the automatic mode.

[0033] In some embodiments, the method further includes:

[0034] Set the matcher to the fixed mode.

[0035] In some embodiments, the method further includes:

[0036] Before starting the matrix scanning operation, set the input step size and step interval of the matrix scanning.

[0037] In some embodiments, if the preset determination condition is not satisfied, reset the input step size and step interval of the matrix scanning and start the matrix scanning; and / or

[0038] If the optimal matching condition is not satisfied, reset the input step size and step interval of the matrix scanning and start the matrix scanning.

[0039] In some embodiments, the step of starting the matrix scanning operation, sequentially changing the first adjustable capacitance parameter and / or the second adjustable capacitance parameter value in the matrix, and recording the corresponding reflected power and output frequency value as the element value of the corresponding matrix position further includes:

[0040] Manually adjust and change the first adjustable capacitance parameter and / or the second adjustable capacitance parameter value in the matrix, and record the corresponding reflected power and output frequency value as the element value of the corresponding matrix position.

[0041] In some embodiments, after the step of taking the current preselected matching value as the optimal matching value, further includes:

[0042] Use the first adjustable capacitance parameter and the second adjustable capacitance parameter corresponding to the optimal matching value as fixed parameters for semiconductor process operations.

[0043] In some embodiments, the preset target frequency value is the target starting frequency.

[0044] To achieve the above object, the present invention provides a system for impedance matching based on a matrix matching diagram, including a radio frequency power supply, a matcher, a controller, and a cavity load:

[0045] The radio frequency power supply is used to provide radio frequency energy;

[0046] The matcher is located between the radio frequency power supply and the cavity load and is used to adjust the impedance matching between the radio frequency power supply and the cavity load;

[0047] The matcher includes at least a first adjustable capacitor and a second adjustable capacitor;

[0048] The controller is connected to the matcher and is configured to control the matcher to perform the impedance matching method based on the matrix matching diagram as described above;

[0049] The cavity load is used for semiconductor processes.

[0050] In some embodiments, the controller includes a first control unit that interacts with the matcher for data:

[0051] The first control unit is configured to send control instructions to the matcher to adjust the parameters of the first adjustable capacitor and / or the second adjustable capacitor of the matcher; switch between the automatic mode and the fixed mode of the matcher; and

[0052] is configured to receive the matching value result output by the matcher.

[0053] In some embodiments, the controller further includes a second control unit:

[0054] The second control unit is connected to the first control unit and is configured to execute the impedance matching method based on the matrix matching diagram and control the first control unit to achieve data interaction between the first control unit and the matcher.

[0055] In some embodiments, the matcher includes a fixed capacitor C0, a fixed inductor L0, a first adjustable capacitor C1, a second adjustable capacitor C2, a first inductor L1, and a second inductor L2:

[0056] One end of the fixed capacitor C0 is grounded, and the other end is connected to the fixed inductor L0, and is configured to provide a basic capacitance value;

[0057] The fixed inductor L0 is connected to the fixed capacitor C0 and is configured to provide a basic inductance value;

[0058] The first adjustable capacitor C1 is connected in series in the subsequent circuit and is connected to the first inductor L1;

[0059] The second adjustable capacitor C2 is connected in parallel in the subsequent circuit, one end is grounded, and the other end is connected to the second inductor L2;

[0060] Impedance matching is achieved by adjusting the parameters of the first adjustable capacitor and the second adjustable capacitor.

[0061] The present invention provides a method and system for impedance matching based on a matrix matching graph. By using a matrix scanning method, the optimal matching parameters of the impedance matcher can be accurately identified, enabling efficient and stable impedance matching between the RF power supply and the cavity load, adapting to impedance changes under different process conditions, not only effectively reducing the reflected power loss, but also ensuring the stability of the output frequency of the matcher, thereby significantly improving the stability and reliability of the semiconductor process. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The above and other features, properties, and advantages of the present invention will become more apparent from the following description in conjunction with the drawings and embodiments, where like reference numerals in the drawings always denote like features, wherein:

[0063] Figure 1 Discloses a flowchart of a method for impedance matching based on a matrix matching graph according to an embodiment of the present invention;

[0064] Figure 2 Discloses a block diagram of the system principle for impedance matching based on a matrix matching graph according to an embodiment of the present invention;

[0065] Figure 3 Discloses an initial schematic diagram of a matrix matching graph according to an embodiment of the present invention;

[0066] Figure 4 Discloses a first result schematic diagram of a matrix matching graph according to an embodiment of the present invention;

[0067] Figure 5 Discloses a second result schematic diagram of a matrix matching graph according to an embodiment of the present invention;

[0068] Figure 6 Discloses a third result schematic diagram of a matrix matching graph according to an embodiment of the present invention;

[0069] Figure 7 Discloses a fourth result schematic diagram of a matrix matching graph according to an embodiment of the present invention.

[0070] The meanings of the reference numerals in the drawings are as follows:

[0071] 10 RF power supply;

[0072] 20 matcher;

[0073] 30 controller;

[0074] 31 first control unit;

[0075] 32 second control unit;

[0076] 40 cavity load. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0077] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the invention and are not used to limit the invention.

[0078] A method and system for impedance matching based on a matrix matching diagram provided by the present invention effectively solve the problem in the prior art that the impedance value fluctuates due to process condition changes, thereby affecting the matching efficiency. The present invention can efficiently and stably achieve impedance matching between a radio frequency power supply and a reaction chamber, ensure that the plasma in the reaction chamber obtains sufficient energy for process operations, avoid radio frequency power loss or process instability caused by improper impedance matching, not only adapt to long-term changes in process conditions, but also greatly improve the matching efficiency and production stability, and have broad industrial application prospects.

[0079] Figure 1 Discloses a method step diagram of impedance matching based on a matrix matching diagram according to an embodiment of the present invention, as Figure 1 shown, the method for impedance matching based on a matrix matching diagram provided by the present invention includes the following steps:

[0080] Step S1, start the radio frequency power supply, set a matching value as the initial point, and the matching value is a set of first adjustable capacitor parameters and second adjustable capacitor parameters;

[0081] Step S2, configure a matrix with the initial point as the scanning starting point, and the rows and columns of the matrix are respectively composed of the first adjustable capacitor parameters and the second adjustable capacitor parameters;

[0082] Step S3, start the matrix scanning operation, sequentially change the values of the first adjustable capacitor parameters and / or the second adjustable capacitor parameters in the matrix, and record the corresponding reflected power and output frequency values as the element values of the corresponding matrix positions;

[0083] Step S4, generate a matrix matching diagram based on all the matrix element value data;

[0084] Step S5, judge whether each element value data in the matrix matching diagram meets a preset judgment condition. If it meets the preset judgment condition, use the current element value data as the preselected matching value. If all the element value data do not meet the preset judgment condition, return to Step S1, reset the initial point and start the matrix scanning. The preset judgment condition is related to the reflected power value and the output frequency value;

[0085] Step S6, generate a preselected matching value set from all the preselected matching values;

[0086] Step S7: Determine whether each preselected matching value in the set of preselected matching values meets the best matching condition. If it meets the best matching condition, use the current preselected matching value as the best matching value. If all preselected matching values do not meet the best matching condition, return to Step S1, reset the initial point and start matrix scanning, and repeat the above steps;

[0087] The best matching condition is related to the element value data around the preselected matching value.

[0088] Among them, a matcher is used to adjust the impedance matching between the RF power supply and the cavity load in the plasma processing equipment. The matcher includes at least a first adjustable capacitor and a second adjustable capacitor.

[0089] The impedance matching method based on the matrix matching graph provided by the present invention significantly shortens the matching time, improves the matching accuracy and efficiency at the same time, and further ensures the stability of the output frequency. This efficient and accurate matching method can improve the stability and consistency of the semiconductor process, realize the controllability of the process thickness, and significantly improve the repeatability and reliability of the process.

[0090] Figure 2 Discloses a system principle block diagram of impedance matching based on a matrix matching graph according to an embodiment of the present invention, as Figure 2 shown, a system for impedance matching based on a matrix matching graph provided by the present invention includes an RF power supply 10, a matcher 20, a controller 30, and a cavity load 40:

[0091] The RF power supply 10 is connected to the matcher 20 and is used to provide RF energy;

[0092] The matcher 20 is located between the RF power supply 10 and the cavity load 40 and is used to adjust the impedance matching between the RF power supply 10 and the cavity load 40;

[0093] The controller 30 is connected to the matcher 20 and is used to control the matcher 20 to execute the impedance matrix matching method as Figure 1 shown;

[0094] The cavity load 40 is used for semiconductor processing.

[0095] Furthermore, the controller 30 at least includes a first control unit 31 that interacts with the matcher for data:

[0096] The first control unit 31 is used to send control instructions to the matcher 20 to adjust the first adjustable capacitor parameter and / or the second adjustable capacitor parameter of the matcher 20; switch the automatic (Auto) mode and the fixed (Fix) mode of the matcher 20; and receive the matching value result output by the matcher 20.

[0097] Furthermore, the controller 30 may further include a second control unit 32:

[0098] The second control unit 32, connected to the first control unit 31, is configured to execute an impedance matching method for the matcher 20 based on matrix adjustment and control the first control unit 31 to achieve data interaction between the first control unit 31 and the matcher 20.

[0099] The second control unit 32 is not necessary during the process of manually performing matrix scanning and generating a matrix matching diagram, etc., and is only enabled when automatically executed. Specific details will be elaborated in the subsequent method description.

[0100] In this embodiment, the controller 30 can be designed to be jointly implemented by the above two independent control units (the first control unit 31 and the second control unit 32). In other embodiments, its functions can also be integrated into a complete control unit. The design of this controller 30 has the flexibility of modularization and integration, and can be adjusted according to actual application requirements to improve system control efficiency and matching accuracy.

[0101] In this embodiment, the matcher 20 adjusts the values of the first capacitance parameter C1 (Tune) on the series circuit and the second capacitance parameter C2 (Match) on the parallel circuit to achieve matching between the output impedance (50 Ω) of the RF power supply 10 and the input impedance of the cavity load 40, and reduce the reflected power loss.

[0102] Furthermore, the matcher 20 includes a fixed capacitor C0, a fixed inductor L0, a first adjustable capacitor C1, a second adjustable capacitor C2, a first inductor L1, and a second inductor L2:

[0103] One end of the fixed capacitor C0 is grounded, and the other end is connected to the fixed inductor L0, and is used to provide a basic capacitance value;

[0104] The fixed inductor L0 is connected to the fixed capacitor C0 and is used to provide a basic inductance value;

[0105] The first adjustable capacitor C1 is connected in series in the subsequent circuit and is connected to the first inductor L1. By adjusting the value of the first adjustable capacitance parameter (Tune), the impedance of the series circuit can be accurately controlled.

[0106] The second adjustable capacitor C2 is connected in parallel in the subsequent circuit, one end is grounded, and the other end is connected to the second inductor L2. By adjusting the value of the second adjustable capacitance parameter (Match), the impedance of the matching circuit is further optimized to achieve a refined adjustment of the input impedance of the cavity load 40.

[0107] Impedance matching is achieved by adjusting the parameters of the first adjustable capacitor and the second adjustable capacitor. Adjusting the values of these two parameters can precisely adjust the impedance matching between the RF power supply 10 and the cavity load 40 to reduce the reflected power and improve the energy transfer efficiency.

[0108] The following takes the impedance matching system based on the matrix matching diagram as shown in Figure 2 as an example to specifically illustrate the impedance matching method based on the matrix matching diagram proposed by the present invention.

[0109] Step S1: Start the RF power supply 10 and set a matching value as the initial point. The matching value is a set of parameters of the first adjustable capacitor (Tune value) and the second adjustable capacitor (Match value).

[0110] The initial point can be either manually input or automatically obtained:

[0111] The manual input means directly inputting the matching value by the user; the automatic acquisition means that by switching the matcher 20 to the automatic mode, the matcher 20 automatically adjusts and obtains the matching value.

[0112] In this embodiment, the matcher 20 has two working modes, including the automatic mode and the fixed mode:

[0113] In the automatic mode, the output frequency of the RF signal is fixed. The matcher 20 will automatically adjust the parameters of the first adjustable capacitor and the second adjustable capacitor to obtain the matching value to achieve impedance matching. However, since the adjustment of the matcher 20 is achieved by controlling the rotation of the capacitor position by a stepper motor, and the stepper motor belongs to a mechanical structure, the adjustment speed is slow, and the response time is usually in the second-level range. In addition, in the automatic mode, the output frequency of the RF signal may fluctuate within the range of ±10%.

[0114] In this embodiment, by configuring the matcher to the automatic mode in step S1, an initial point can be effectively obtained as a matching point. For example, automatic matching generates a set of matching values: the Tune / Match value is 50 / 50 as the initial point.

[0115] In this embodiment, the parameter of the first adjustable capacitor (Tune value) represents the relative degree of adjustment of the first adjustable capacitor C1, that is, the ratio of the current adjustable capacitor value to the maximum adjustable capacitor value, and the value range is 0% to 100%. A Tune value of 50 means that the ratio of the current adjustable capacitor value to the maximum adjustable capacitor value is 50%.

[0116] The parameter of the second adjustable capacitor (Match value) represents the relative degree of adjustment of the second adjustable capacitor C2, that is, the ratio of the current adjustable capacitor value to the maximum adjustable capacitor value, and the value range is also 0% to 100%.

[0117] In the present invention, by configuring the matcher to the automatic mode, an initial point can be effectively obtained as a matching point. If the initial point is obtained through the automatic mode of the matcher, the matcher will switch to the fixed mode after obtaining the initial point. In the fixed mode, step S2 performs a further rapid matching operation through a frequency sweep operation, and in combination with the matrix adjustment method, the optimal matching value is accurately found. In some embodiments, the initial point can also be manually input, and the operation of manually inputting the initial point is completed when the matcher is set to the fixed mode, so as to directly optimize the matching value through the frequency sweep and matrix adjustment methods; the manually input initial point can be set according to process experience, for example.

[0118] During the matrix scanning process in the fixed mode, the output frequency can be maintained within a range close to the target frequency of 13.56 MHz (the standard frequency of the plasma deposition process), and it is ensured that the deviation of its output frequency is controlled within ±5% (13.56 MHz ± 0.68 MHz). The finally determined optimal matching value makes the reflected power zero, maximizes the RF power transmission efficiency and meets the requirements of the semiconductor process for the output frequency value.

[0119] Step S2: Configure a matrix with the initial point as the scanning starting point, where the rows and columns of the matrix are respectively composed of the first adjustable capacitance parameter and the second adjustable capacitance parameter;

[0120] Figure 3 Reveals an initial schematic diagram of a matrix matching diagram according to an embodiment of the present invention, as Figure 3 shown, the controller 30 takes the initial point with a Tune / Match value of 50 / 50 as the center point of the matrix, inputs the step size (step) and the step size interval value (step interval value), and generates a two-dimensional matrix centered on the initial point as a reference.

[0121] After the matrix is generated, the matching value (Tune / Match value) of the initial point in step S1 will be displayed at the central position of the matrix.

[0122] The rows and columns of the matrix respectively represent different Tune values and Match values, and each grid is initialized. Each matrix element displays the default values of the reflected power and the output frequency, and the default value of the element value of the initial point is p0 / f0.

[0123] Step S3: Start the matrix scanning operation, sequentially change the values of the first adjustable capacitance parameter and / or the second adjustable capacitance parameter in the matrix, and record the corresponding reflected power and output frequency values as the matrix element values at the corresponding positions;

[0124] After clicking "Start", the controller 30 automatically changes the Tune value or Match value of each cell in the matrix point by point, inputs it into the matcher 20, records the corresponding reflected power and output frequency value, and fills them into the element values at the corresponding matrix positions.

[0125] Step S4, generating a matrix matching graph based on all the matrix element value data;

[0126] After the matrix scanning is completed, the controller 30 finally generates a matrix matching graph based on the recorded data. Each element value in the matrix matching graph corresponds to the reflected power and output frequency value recorded by adjusting the Tune / Match value.

[0127] Step S5, judging whether each element value data in the matrix matching graph meets the preset judgment condition. If it meets the preset judgment condition, the current element value data is used as the preselected matching value. If all the element value data do not meet the preset judgment condition, return to step S1 to reset the initial point and start the matrix scanning.

[0128] Judging each element value data of the matrix matching graph in turn to determine whether it meets the preset judgment condition.

[0129] The preset judgment condition is closely related to the reflected power value and the output frequency value.

[0130] In this embodiment, the preset judgment condition at least includes: the reflected power is equal to 0 and the absolute value of the difference between the output frequency value and the preset target frequency value is the smallest. At this time, the output frequency value is closest to the preset target frequency value. If the current element value data meets the condition that the reflected power is equal to 0 and the absolute value of the difference between the output frequency value and the preset target frequency value is the smallest, the current element value data is used as the preselected matching value.

[0131] To improve the matching accuracy and matching efficiency, the preset judgment condition is further refined into two-level judgment:

[0132] The first judgment condition: the reflected power is equal to 0, and the difference between the output frequency and the preset target frequency value is within the first preset frequency threshold range. The element value data that meets the first judgment condition is selected to form the first judgment matching value set;

[0133] The second judgment condition is that the reflected power is equal to 0 and the absolute value of the difference between the output frequency value and the preset target frequency value is the smallest.

[0134] At this time, step S5 specifically includes the following steps:

[0135] For each element value data in the matrix matching graph, determine one by one whether it meets the first determination condition, select the element value data that meets the first determination condition as the first determination matching value, and generate a first determination matching value set from all the first determination matching values;

[0136] For each element value data in the first determination matching value set, determine whether it meets the second determination condition, and select the element value data that meets the second determination condition as the preselected matching value.

[0137] The above two-level determination method can effectively narrow the candidate range, accurately locate the preselected matching value, ensure that the output frequency value is as close as possible to the preset target frequency value, and at the same time achieve efficient matching with zero reflected power.

[0138] Furthermore, during the first determination, all element value data with a reflected power equal to 0 can be found first, and then data with the difference between the output frequency and the target frequency value within the preset range can be screened out from these data. Such two-step operations can more efficiently narrow the matching range and further improve the accuracy of the matching process.

[0139] Figure 4 Disclosed is a first result schematic diagram of a matrix matching graph according to an embodiment of the present invention, as Figure 4 shown. Assuming that the preset target frequency value is the starting frequency of 13.56 MHz, which is a key frequency range for semiconductor processes such as plasma deposition, the first preset frequency threshold range is, for example, ±0.5 MHz. Therefore, the allowable output frequency range is 13.56 ± 0.5 MHz. It should be understood that the first preset frequency range can also be other ranges suitable for plasma semiconductor processes.

[0140] As Figure 4 shown, through the first determination condition, Tune / Match values that meet the conditions are obtained to generate a first determination matching value set. For example, Tune / Match values 50 / 50 and 51 / 50 both meet the first determination condition, so they belong to the first determination matching value set. However, when further screening according to the second determination condition, it is found that the output frequency of the Tune / Match value 50 / 50 is 13.57 MHz, which is not the closest to the target frequency of 13.56 MHz; on the contrary, the output frequency of the Tune / Match value 51 / 50 is 13.56 MHz and the reflected power is 0, so it is selected as the preselected matching value.

[0141] It should be noted that in the above step S5, if the current element value data does not meet the preset determination condition, continue to select the next element value data for determination. If all element value data do not meet the preset determination condition, return to step S1, and the following adjustment methods can be adopted:

[0142] Restart the matrix scan after the input step size and step size interval of the matrix scan can be reset again, or restart the matrix scan after resetting the initial point.

[0143] Step S6, generate a set of preselected matching values from all the preselected matching values.

[0144] There may be more than one preselected matching value obtained through step S5. These preselected matching values are taken as a set. Subsequently, this set will be further screened and optimized through subsequent steps, and finally an optimal matching value will be selected to meet the higher-precision matching requirements.

[0145] Step S7, determine whether each preselected matching value in the set of preselected matching values meets the optimal matching condition. If it meets the optimal matching condition, the current preselected matching value is taken as the optimal matching value. If all preselected matching values do not meet the optimal matching condition, reset the initial point and start the matrix scan, and repeat the above steps. The optimal matching condition is related to the element value data around the preselected matching value.

[0146] The optimal matching condition is related to the matrix element value data around the preselected matching value. Its core is to verify the stability and reliability of the preselected matching value within a certain range.

[0147] In this embodiment, the optimal matching condition includes the following:

[0148] Taking the current preselected matching value as the center point, judge that the matrix element values within the specified range around the center point all satisfy that the reflection power is equal to 0, and the difference between the output frequency and the preset target frequency value is within the second preset frequency threshold range.

[0149] By checking the reflection power and output frequency of the matrix element values around the center point, verify whether the preselected matching value performs well in a wider range, thereby improving the stability and reliability of the process.

[0150] In this embodiment, the second preset frequency threshold range is the same as the first preset frequency threshold range. However, obviously, the second preset frequency threshold range can also be inconsistent with the first preset frequency threshold range. Preferably, the second preset frequency range can be smaller than the first preset frequency range. In addition, the second preset frequency range can also be a frequency range suitable for other plasma semiconductor processes, and this situation is also covered by the protection scope of the present invention.

[0151] If the matrix element values around the center point satisfy the conditions that the reflection power is equal to 0 and the difference between the output frequency and the preset target frequency value is within the second preset frequency threshold range, it indicates that the preselected matching value is not only accurate, but also has good fault tolerance and stability, and can adapt to the dynamic load changes that may occur in the process. Therefore, it is suitable as the optimal matching condition.

[0152] Through this step of verifying the optimal matching value, it is possible to avoid re - matching through the matcher every time the cavity load changes, thereby reducing the negative impact on process stability caused by frequent adjustments. The tolerance range of the optimal matching value ensures the stability of the load conditions during the process, improving the reliability and repeatability of the process operation. In addition, the tolerance of the optimal matching value enables it to adapt to small changes in the cavity load without frequent adjustments, significantly improving the process efficiency and quality.

[0153] In this embodiment, the specified range around the center point constitutes a matrix composed of the matrix element values of an N - row × N - column matrix, where N is greater than or equal to 3, that is, at least a 3×3 square matrix.

[0154] Take Figure 5 the second result as an example. Taking the Tune / Match value 51 / 50 as the center point, if the element value data within the 3×3 matrix range around it satisfies the condition that the reflected power is equal to 0 and the difference between the output frequency and the preset target frequency value of 13.56 MHz is within ±0.5 MHz, then this pre - selected matching value is considered the optimal matching value;

[0155] Take Figure 6 the third result as an example. Taking the Tune / Match value 51 / 50 as the center point, within the 3×3 matrix range around it, although the Tune / Match value 50 / 49 satisfies that the reflected power is equal to 0, but the output frequency of 15.66 MHz is too large compared with the preset target frequency value of 13.56 MHz, exceeding the range of 0.5 MHz, then this pre - selected matching value is not considered the optimal matching value.

[0156] If the matrix range is less than 3×3, such as the 2×2 matrix shown in Figure 4 , then this pre - selected matching value is not considered the optimal matching value, and continue to search for the next suitable pre - selected matching value.

[0157] If the matrix range is greater than 3×3 (i.e., N > 3), then consider that the center position of the matrix is not unique. Select a point with the output frequency closest to the preset target frequency value among the four points in the center as the judgment reference. If there are multiple closest points, judge them in turn.

[0158] Take Figure 7Taking the fourth result as an example, the matrix range is 4×4. First, among the four points of Tune / Match value 51 / 50, Tune / Match value 52 / 50, Tune / Match value 50 / 51, and Tune / Match value 52 / 51, select the point Tune / Match value 51 / 50 with the output frequency closest to the preset target frequency value as the center point. Then, taking this point of Tune / Match value 51 / 50 as the center point, construct a 3×3 matrix range, and check again whether the element values within this matrix range meet the following conditions:

[0159] The condition that the reflected power is equal to 0 and the difference between the output frequency and the preset target frequency value of 13.56 MHz is within 0.5 MHz, for example.

[0160] If the 3×3 matrix formed by the Tune / Match value 51 / 50 meets the above conditions, it is considered that this preselected matching value is the best matching value. If the above conditions are not met, continue to find the next suitable preselected matching value. If all preselected matching values do not meet the requirements, return to step S1.

[0161] It should be understood that for Figure 7 the result, the above inspection process may be unnecessary. Since this center point is located at the center (one of) of the 4×4 matrix, there must be a 3×3 matrix range around this point that meets the above conditions.

[0162] In some embodiments, among the preselected matching values with a matrix range of 4×4, there are two or more best matching values among the four center points;

[0163] It should be noted that in the above step S7, if the current preselected matching value does not meet the best matching condition, select the next preselected matching value for judgment. If all preselected matching values do not meet the conditions, the input step size and step interval of the matrix scan can be reset and the matrix scan can be started, or the initial point can be reset and return to step S1.

[0164] It should be understood that according to the matrix matching method of the present invention, at least one best matching value can be found for the matcher. In some embodiments, there are multiple best matching values, and the present invention does not limit this.

[0165] When determining the optimal matching conditions, the specified range around the center point can adopt various different shapes. Although in this embodiment, a square matrix (such as a 3×3 matrix) is adopted as the judgment range, and it is considered to be an ideal way, in fact, other shapes (such as rectangles, rings, or even irregular shapes) can also be used for such determination. These different shapes can also effectively judge whether the matching value meets the optimal matching conditions. Therefore, other shapes except squares should also be included in the protection scope of this application. The square range given in this embodiment is only a preferred example for implementing this method and does not limit the application of this method.

[0166] Furthermore, after the step S7, it further includes:

[0167] Taking the first adjustable capacitance parameter and the second adjustable capacitance parameter corresponding to the optimal matching value as fixed parameters, semiconductor process operations are performed.

[0168] Writing the Tune and Match values corresponding to the optimal matching value into the process parameters, so that the matcher 20 fixedly outputs these values during subsequent process. Running the process in the fixed mode can significantly improve the stability of the process operation and enhance the production efficiency.

[0169] Furthermore, on the basis of automatically generating the matrix, the user can also manually adjust the matrix diagram to find the optimal matching value, further improving the matching accuracy.

[0170] The step S3 further includes:

[0171] Manually adjusting and changing the first adjustable capacitance parameter (Tune value) and / or the second adjustable capacitance parameter (Match value) in the matrix, recording the corresponding reflected power and output frequency values as the matrix element values at the corresponding positions, and generating a matrix matching diagram based on all the matrix element value data.

[0172] When using the manual method, the first control unit 31 of the controller 30 is used to input adjustment parameters (such as Tune and Match values) to the matcher 20 and receive the matching results. The operation of the second control unit 32 can be generated manually. For example, the user manually adjusts the capacitance parameters through the first control unit 31 and then generates the corresponding matrix.

[0173] The user can center around the output matching value, arrange the Tune and Match values in an arithmetic progression, set the step size and the step size interval (tolerance), so as to construct a matrix similar to Figure 3 as shown. In this way, the user can manually control the fineness of the matching process and further optimize the impedance matching.

[0174] In a manually generated matrix, the smaller the reflected power, the lower the loss of radio frequency energy, and the better the matching effect.

[0175] When the reflected power is 0 and the output frequency value is closest to the preset target frequency, the impedance matching reaches the optimal state, ensuring the maximization of the energy transfer efficiency in the process.

[0176] Through manual adjustment, the user can finely adjust the matching parameters according to the actual process requirements, thereby improving the matching accuracy and ensuring the stability and accuracy of the output frequency and power transmission.

[0177] Although the above methods are illustrated and described as a series of actions for simplicity of explanation, it should be understood and appreciated that these methods are not limited by the order of the actions, because according to one or more embodiments, some actions may occur in a different order and / or concurrently with other actions that are illustrated and described herein or that are not illustrated and described herein but are understandable to those skilled in the art.

[0178] The present invention provides a method and system for impedance matching based on a matrix matching diagram. By using a matrix scanning method, the optimal matching parameters of the impedance matcher are accurately identified to adapt to impedance changes under different process conditions, not only effectively reducing the reflected power loss, but also ensuring the stability of the output frequency of the matcher, thereby significantly improving the stability and reliability of the semiconductor process.

[0179] As shown in this application and the claims, unless the context clearly indicates otherwise, words such as "a", "an", "one", and / or "the" are not specifically singular and may also include the plural. Generally speaking, the terms "including" and "comprising" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0180] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is 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 should not be construed as a limitation of the present invention.

[0181] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may also include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below" and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.

[0182] In the description of the present invention, it should be noted that, unless otherwise clearly specified or limited, the terms "mounted", "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a direct connection, or an indirect connection through an intermediate medium, and may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention may be understood according to specific circumstances.

[0183] Those skilled in the art will appreciate that information, signals, and data may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, symbols, and chips described throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0184] Those skilled in the art will further appreciate that the various illustrative logical blocks, modules, circuits, and algorithmic steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability of hardware and software, the various illustrative components, blocks, modules, circuits, and steps are described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

[0185] The various illustrative logical modules and circuits described in connection with the embodiments disclosed herein can be implemented or executed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration.

[0186] The above embodiments are provided to those skilled in the art to implement or use the present invention. Those skilled in the art can make various modifications or changes to the above embodiments without departing from the inventive concept of the present invention. Therefore, the protection scope of the present invention is not limited by the above embodiments, but should be the maximum scope that conforms to the innovative features mentioned in the claims.

Claims

1. A method for impedance matching based on a matrix matching graph, characterized in that An impedance matcher is used to adjust the impedance matching between the RF power supply and the cavity load in the plasma processing equipment. The matcher at least includes a first adjustable capacitor and a second adjustable capacitor; The method includes the following steps: Start the RF power supply and set a matching value as the initial point. The matching value is a set of first adjustable capacitor parameters and second adjustable capacitor parameters; Configure a matrix with the initial point as the scanning starting point. The rows and columns of the matrix are respectively composed of the first adjustable capacitor parameters and the second adjustable capacitor parameters; Start the matrix scanning operation, sequentially change the values of the first adjustable capacitor parameters and / or the second adjustable capacitor parameters in the matrix, and record the corresponding reflected power and output frequency values as the element values at the corresponding matrix positions; Generate a matrix matching graph based on all the matrix element value data; Judge whether each element value data in the matrix matching graph meets the preset judgment condition. If it meets the preset judgment condition, the current element value data is used as the preselected matching value. If all the element value data do not meet the preset judgment condition, reset the initial point and start the matrix scanning. The preset judgment condition is related to the reflected power value and the output frequency value; Generate a set of preselected matching values from all the preselected matching values; Judge whether each preselected matching value in the set of preselected matching values meets the best matching condition. If it meets the best matching condition, the current preselected matching value is used as the best matching value. If all the preselected matching values do not meet the best matching condition, reset the initial point and start the matrix scanning, and repeat the above steps; The best matching condition is related to the element value data around the preselected matching value.

2. The impedance matching method based on matrix matching graph according to claim 1, wherein The preset judgment condition at least includes: the reflected power is equal to 0 and the absolute value of the difference between the output frequency value and the preset target frequency value is the smallest; The step of judging whether each element value data in the matrix matching graph meets the preset judgment condition includes: If the current element value data meets the condition that the reflected power is equal to 0 and the absolute value of the difference between the output frequency value and the preset target frequency value is the smallest, the current element value data is used as the preselected matching value.

3. The impedance matching method based on matrix matching graph according to claim 1, wherein The preset judgment condition at least includes a first judgment condition and a second judgment condition: The first judgment condition is that the reflected power is equal to 0, and the difference between the output frequency and the preset target frequency value is within the first preset frequency threshold range; The second judgment condition is that the reflected power is equal to 0, and the absolute value of the difference between the output frequency value and the preset target frequency value is the smallest; The step of judging whether each element value data in the matrix matching graph meets the preset judgment condition includes: Judge whether each element value data in the matrix matching graph meets the first judgment condition, select the element value data that meets the first judgment condition as the first judgment matching value, and generate a set of first judgment matching values from all the first judgment matching values; Judge whether each element value data in the set of first judgment matching values meets the second judgment condition, and select the element value data that meets the second judgment condition as the preselected matching value.

4. The impedance matching method based on a matrix matching graph according to claim 1, characterized in that The best matching condition is: Taking the current preselected matching value as the center point, it is determined that the matrix element values within a specified range around the center point all satisfy that the reflection power is equal to 0, and the difference between the output frequency and the preset target frequency value is within the second preset frequency threshold range.

5. The method for impedance matching based on a matrix matching graph according to claim 4, wherein The specified range around the center point constitutes a matrix composed of matrix element values of N rows multiplied by N columns, where N is greater than or equal to 3.

6. The method for impedance matching based on a matrix matching graph according to claim 1, characterized in that The method further includes: Before starting the matrix scanning operation, set the input step size and step size interval of the matrix scanning.

7. The impedance matching method based on matrix matching graph according to claim 6, wherein If the preset determination condition is not satisfied, reset the input step size and step size interval of the matrix scanning and start the matrix scanning; and / or If the best matching condition is not satisfied, reset the input step size and step size interval of the matrix scanning and start the matrix scanning.

8. The impedance matching method based on matrix matching graph according to claim 1, wherein The step of starting the matrix scanning operation, sequentially changing the first adjustable capacitance parameter and / or the second adjustable capacitance parameter value in the matrix, and recording the corresponding reflection power and output frequency value as the element value of the corresponding matrix position, further includes: Manually adjust and change the first adjustable capacitance parameter and / or the second adjustable capacitance parameter value in the matrix, and record the corresponding reflection power and output frequency value as the element value of the corresponding matrix position.

9. The impedance matching method based on matrix matching graph according to claim 1, characterized in that After the step of taking the current preselected matching value as the best matching value, further includes: Taking the first adjustable capacitance parameter and the second adjustable capacitance parameter corresponding to the best matching value as the fixed parameters of the matcher, and performing semiconductor process operations.

10. The method for impedance matching based on a matrix matching graph according to any one of claims 2 to 4, characterized in that The preset target frequency value is the target starting frequency.

11. An impedance matching system based on a matrix matching graph, characterized in that, It includes a radio frequency power supply, a matcher, a controller, and a cavity load: The radio frequency power supply is used to provide radio frequency energy; The matcher is located between the radio frequency power supply and the cavity load, and is used to adjust the impedance matching between the radio frequency power supply and the cavity load; The matcher includes at least a first adjustable capacitance and a second adjustable capacitance; The controller is connected to the matcher and is used to control the matcher to execute the impedance matching method based on the matrix matching diagram as described in any one of claims 1 to 10; The cavity load is used to perform semiconductor processes.

12. The impedance matching system based on a matrix matching graph according to claim 11, wherein The controller includes at least a first control unit for data interaction with the matcher: The first control unit is used to send control instructions to the matcher to adjust the first adjustable capacitance parameter and / or the second adjustable capacitance parameter of the matcher; switch the automatic mode and the fixed mode of the matcher; and is used to receive the matching value result output by the matcher.

13. The impedance matching system based on a matrix matching graph according to claim 12, characterized in that, The controller further includes a second control unit: The second control unit is connected to the first control unit and is used to execute the impedance matching method based on the matrix matching diagram and control the first control unit to realize the data interaction between the first control unit and the matcher.

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