Impedance matching method and system based on matrix matching graph

Abstract

The invention relates to the technical field of semiconductors, in particular to an impedance matching method and system based on a matrix matching graph. The method comprises the following steps: starting a radio frequency power supply, and setting a matching value as an initial point; configuring a matrix taking the initial point as a scanning starting point; matrix scanning operation is started to record corresponding reflection power and output frequency values as element values of corresponding matrix positions; generating a matrix matching graph based on all the matrix element value data; judging each piece of element value data, and taking the current element value data as a pre-selected matching value if a condition is met; and judging each pre-selected matching value, and taking the current pre-selected matching value as the optimal matching value if the optimal matching condition is met. According to the method, the optimal matching parameters of the impedance matcher are accurately identified through a matrix scanning method, impedance changes under different process conditions are adapted, and the stability and reliability of the semiconductor process are remarkably improved.

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 adjustable capacitor. Since the consumable components in the plasma reaction chamber will gradually wear out with use, the impedance of the chamber will continue to change under the same process conditions. Therefore, if the initial capacitance value of the adjustable capacitor remains unchanged, the impedance matching process may gradually lose consistency, 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 needs to be overcome urgently. Summary of the invention

[0009] The purpose of the present invention is to provide a method and system for impedance matching based on a matrix matching diagram, so as to solve the problems in the prior art of reduced matching efficiency and unstable energy transmission caused by impedance changes of plasma processing equipment.

[0010] In order to achieve the above object, the present invention provides an impedance matching method based on a matrix matching diagram, using a matcher to adjust the impedance matching between a radio frequency power supply and a cavity load in a plasma processing device, wherein the matcher includes at least a first adjustable capacitor and a second adjustable capacitor;

[0011] The method comprises the following steps:

[0012] Starting the radio frequency power supply, setting a matching value as an initial point, wherein the matching value is a set of a first adjustable capacitance parameter and a second adjustable capacitance parameter;

[0013] A matrix is ​​configured with the initial point as the scanning starting point, wherein the rows and columns of the matrix are respectively composed of the first adjustable capacitance parameter and the second adjustable capacitance parameter;

[0014] Start a matrix scanning operation, change the first adjustable capacitance parameter and / or the second adjustable capacitance parameter value in the matrix in turn, and record the corresponding reflected power and output frequency value as the element value of the corresponding matrix position;

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

[0016] Determine whether each element value data in the matrix matching diagram meets the preset determination conditions. If the preset determination conditions are met, the current element value data is used as the pre-selected matching value. If the preset determination conditions are not met, the initial point is reset and the matrix scan is started. The preset determination conditions are related to the reflected power value and the output frequency value.

[0017] Generate a pre-selected matching value set from all pre-selected matching values;

[0018] Determine whether each pre-selected matching value in the pre-selected matching value set meets the best matching condition. If the best matching condition is met, the current pre-selected matching value is used as the best matching value. If the best matching condition is not met, reset the initial point and start matrix scanning, and repeat the above steps.

[0019] The optimal matching condition is related to element value data surrounding the preselected matching value.

[0020] In some embodiments, the preset determination condition includes at least: 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 judging whether each element value data in the matrix matching graph meets the preset judgment condition comprises:

[0022] If the current element value data satisfies 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 pre-selected matching value.

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

[0024] 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;

[0025] 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;

[0026] The step of judging whether each element value data in the matrix matching graph meets the preset judgment condition comprises:

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

[0028] It is judged whether each element value data in the first determination matching value set satisfies the second determination condition, and the element value data satisfying the second determination condition is selected as the pre-selected matching value.

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

[0030] 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 reflected power is equal to 0, and the difference between the output frequency and the preset target frequency value is within a second preset frequency threshold range.

[0031] In some embodiments, the specified range around the center point constitutes a matrix consisting of N rows by N columns of matrix element values, where N is greater than or equal to 3.

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

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

[0034] Set the matcher to a fixed pattern.

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

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

[0037] In some embodiments, if the preset determination condition is not met, the input step size and step size interval of the matrix scan are reset and the matrix scan is started; and / or

[0038] If the optimal matching condition is not met, the input step size and step size interval of the matrix scan are reset and the matrix scan is started.

[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 values ​​as element values ​​of the corresponding matrix position further includes:

[0040] The first adjustable capacitance parameter and / or the second adjustable capacitance parameter value in the matrix is ​​adjusted and changed manually, and the corresponding reflected power and output frequency values ​​are recorded as element values ​​of the corresponding matrix positions.

[0041] In some embodiments, after the step of using the current pre-selected matching value as the best matching value, the method further comprises:

[0042] The semiconductor process operation is performed using the first adjustable capacitance parameter and the second adjustable capacitance parameter corresponding to the best matching value as fixed parameters.

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

[0044] In order to achieve the above object, the present invention provides an impedance matching system 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 RF power supply and the cavity load, and is used to adjust the impedance matching between the RF power supply and the cavity load;

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

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

[0049] The chamber load is used for performing semiconductor processes.

[0050] In some embodiments, the controller includes a first control unit for data interaction with the matchmaker:

[0051] The first control unit is used to send a control instruction 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

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

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

[0054] The second control unit is connected to the first control unit, and is used to execute an impedance matching method based on a matrix matching diagram, and control the first control unit to realize 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] The fixed capacitor C0 has one end grounded and the other end connected to the fixed inductor L0, for providing a basic capacitance value;

[0057] The fixed inductor L0 is connected to the fixed capacitor C0 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 of which is grounded, and the other end is connected to the second inductor L2;

[0060] Impedance matching is achieved by adjusting the first adjustable capacitance parameter and the second adjustable capacitance parameter.

[0061] The present invention provides an impedance matching method and system based on a matrix matching diagram. The optimal matching parameters of an impedance matcher are accurately identified through a matrix scanning method, and the impedance matching between a radio frequency power supply and a cavity load can be efficiently and stably achieved, and the impedance changes under different process conditions can be adapted. This not only effectively reduces the reflected power loss, but also ensures 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 through the following description in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always represent the same features, wherein:

[0063] Figure 1 A method step diagram of impedance matching based on a matrix matching diagram according to an embodiment of the present invention is disclosed;

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

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

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

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

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

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

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

[0071] 10. RF power supply;

[0072] 20 matchers;

[0073] 30 controllers;

[0074] 31 first control unit;

[0075] 32 second control unit;

[0076] 40 cavity load. DETAILED DESCRIPTION

[0077] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is 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] The present invention provides an impedance matching method and system based on a matrix matching diagram, which effectively solves the problem in the prior art that the impedance value fluctuates due to changes in process conditions, thereby affecting the matching efficiency. The present invention can efficiently and stably achieve impedance matching between the RF power supply and the reaction chamber, ensuring that the plasma in the reaction chamber obtains sufficient energy for process operations, avoiding RF power loss or process instability caused by improper impedance matching, not only adapting to long-term changes in process conditions, but also greatly improving matching efficiency and production stability, and has broad industrial application prospects.

[0079] Figure 1 A method step diagram of impedance matching based on a matrix matching diagram according to an embodiment of the present invention is disclosed, such as Figure 1 As shown, the impedance matching method based on the matrix matching diagram provided by the present invention comprises the following steps:

[0080] Step S1, starting the radio frequency power supply, setting a matching value as an initial point, wherein the matching value is a set of a first adjustable capacitance parameter and a second adjustable capacitance parameter;

[0081] Step S2, configuring a matrix with the initial point as the scanning starting point, wherein the rows and columns of the matrix are respectively composed of the first adjustable capacitance parameter and the second adjustable capacitance parameter;

[0082] Step S3, 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;

[0083] Step S4, generating a matrix matching graph based on all matrix element value data;

[0084] Step S5, judging whether each element value data in the matrix matching diagram meets the preset judgment condition, if it meets the preset judgment condition, the current element value data is used as the pre-selected matching value, if all element value data do not meet the preset judgment condition, return to step S1, reset the initial point and start the matrix scan, the preset judgment condition is related to the reflected power value and the output frequency value;

[0085] Step S6, generating a pre-selected matching value set from all pre-selected matching values;

[0086] Step S7, judging whether each pre-selected matching value in the pre-selected matching value set meets the best matching condition, if it meets the best matching condition, taking the current pre-selected matching value as the best matching value, if all pre-selected matching values ​​do not meet the best matching condition, returning to step S1, resetting the initial point and starting the matrix scan, and repeating the above steps;

[0087] The optimal matching condition is related to element value data surrounding the preselected matching value.

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

[0089] The impedance matching method based on the matrix matching diagram provided by the present invention significantly shortens the matching time, improves the matching accuracy and efficiency, 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 A system principle block diagram of impedance matching based on a matrix matching diagram according to an embodiment of the present invention is disclosed. Figure 2 As shown, the present invention provides an impedance matching system based on a matrix matching diagram, including a radio frequency power supply 10, a matcher 20, a controller 30 and a cavity load 40:

[0091] The radio frequency power supply 10 is connected to the matching device 20 and is used to provide radio frequency energy;

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

[0093] The controller 30 is connected to the matching device 20 and is used to control the matching device 20 to perform the following steps: Figure 1 The impedance matrix matching method shown;

[0094] The chamber load 40 is used for performing semiconductor processes.

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

[0096] The first control unit 31 is used to send a control instruction to the matcher 20 to adjust the first adjustable capacitance parameter and / or the second adjustable capacitance 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 is connected to the first control unit 31 , and is used to execute the impedance matching method of 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 in the process of manually executing a series of operations such as matrix scanning and generating a matrix matching map, and is only enabled during automatic execution. The specific details will be described in detail in the subsequent method description.

[0100] In this embodiment, the controller 30 can be designed to be implemented by the above two independent control units (the first control unit 31 and the second control unit 32) in collaboration. In other embodiments, its functions can also be integrated into a complete control unit. The design of the controller 30 has modular and integrated flexibility 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 first capacitance parameter C1 (Tune) value in the series circuit and the second capacitance parameter C2 (Match) value in the parallel circuit to achieve matching between the output impedance (50Ω) of the RF power supply 10 and the input impedance of the cavity load 40, thereby reducing 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] The fixed capacitor C0 has one end grounded and the other end connected to the fixed inductor L0, for providing a basic capacitance value;

[0104] The fixed inductor L0 is connected to the fixed capacitor C0 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 parameter (Tune) value of the first adjustable capacitor, the impedance of the series circuit can be accurately controlled.

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

[0107] Impedance matching is achieved by adjusting the first adjustable capacitance parameter and the second adjustable capacitance parameter. Adjustment of these two parameter values ​​can accurately adjust the impedance matching between the RF power source 10 and the cavity load 40 to reduce reflected power and improve energy transmission efficiency.

[0108] The following is Figure 2 Taking the impedance matching system based on the matrix matching diagram shown in the figure as an example, the impedance matching method based on the matrix matching diagram proposed by the present invention is specifically described.

[0109] Step S1, starting the RF power supply 10, setting a matching value as an initial point, wherein the matching value is a set of a first adjustable capacitance parameter (Tune value) and a second adjustable capacitance parameter (Match value);

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

[0111] The manual input refers to the user directly inputting the matching value; the automatic acquisition refers to the matching device 20 automatically adjusting and acquiring the matching value by switching the matching device 20 to the automatic mode.

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

[0113] In the automatic mode, the output frequency of the RF signal is fixed, and the matcher 20 automatically adjusts 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 position of the rotating capacitor by a stepper motor, and the stepper motor is a mechanical structure, the adjustment speed is slow, and the response time is usually in the second 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, the step S1 can effectively obtain a matching point as the initial point by configuring the matcher to the automatic mode. For example, the automatic matching generates a set of matching values: the Tune / Match value is 50 / 50, which is used as the initial point.

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

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

[0117] In the present invention, by configuring the matcher to the automatic mode, a matching point can be effectively obtained as the initial point. If the initial point is obtained by 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 fast matching operation through a frequency sweep operation, and combines the matrix adjustment method to accurately find the best matching value. 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 in the fixed mode, so as to directly optimize the matching value through the frequency sweep and matrix adjustment method; the manually input initial point can be set, for example, according to process experience.

[0118] During the fixed-mode matrix scanning process, 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 its output frequency deviation can be controlled within ±5% (13.56 MHz ± 0.68 MHz). The optimal matching value is finally determined, so that the reflected power reaches zero, maximizing the RF power transmission efficiency and meeting the output frequency value requirements of the semiconductor process.

[0119] Step S2, configuring a matrix with the initial point as the scanning starting point, wherein 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 An initial schematic diagram of a matrix matching graph according to an embodiment of the present invention is disclosed, such as Figure 3 As shown, the controller 30 uses 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 interval value (step interval value), and generates a two-dimensional matrix with the initial point as the center 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 center of the matrix.

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

[0123] Step S3, 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 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 grid in the matrix point by point, and inputs it into the matcher 20, records the corresponding reflected power and output frequency values ​​and fills them into the element values ​​of the corresponding matrix positions.

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

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

[0127] Step S5, judge whether each element value data in the matrix matching diagram meets the preset judgment conditions. If the preset judgment conditions are met, the current element value data is used as the pre-selected matching value. If all element value data do not meet the preset judgment conditions, return to step S1, reset the initial point and start matrix scanning.

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

[0129] The preset determination 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 satisfies the reflected power 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 pre-selected matching value.

[0131] In order to improve the matching accuracy and matching efficiency, the preset judgment conditions are further refined into two levels of judgment:

[0132] 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 a first judgment matching value set;

[0133] 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.

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

[0135] Determine whether each element value data in the matrix matching graph satisfies the first determination condition one by one, select the element value data satisfying 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] It is judged whether each element value data in the first determination matching value set satisfies the second determination condition, and the element value data satisfying the second determination condition is selected as the pre-selected matching value.

[0137] The above two-level determination method can effectively narrow the candidate range and accurately locate the pre-selected matching value, ensuring that the output frequency value is as close as possible to the preset target frequency value, while achieving efficient matching with zero reflected power.

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

[0139] Figure 4 A first result schematic diagram of a matrix matching graph according to an embodiment of the present invention is disclosed, such as Figure 4 As shown, assuming that the preset target frequency value is the ignition 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, and therefore, the allowed output frequency range is 13.56±0.5 MHz. It should be understood that the first preset frequency range may also be other ranges suitable for plasma semiconductor processes.

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

[0141] It should be noted that in the above step S5, if the current element value data does not meet the preset judgment condition, the next element value data is selected for judgment. If all element value data do not meet the preset judgment condition, the process returns to step S1 and can be adjusted in the following ways:

[0142] You can reset the matrix scan input step and step interval and then restart the matrix scan, or reset the initial point and then restart the matrix scan.

[0143] Step S6: All pre-selected matching values ​​are converted into a pre-selected matching value set.

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

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

[0146] The best matching condition is related to the matrix element value data around the pre-selected matching value, and its core is to verify the stability and reliability of the pre-selected matching value within a certain range.

[0147] In this embodiment, the optimal matching conditions include the following:

[0148] 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 reflected power is equal to 0, and the difference between the output frequency and the preset target frequency value is within a second preset frequency threshold range.

[0149] By checking the reflected power and output frequency of the matrix element values ​​around the center point, it is verified that the pre-selected matching values ​​perform well over 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, it is obvious that the second preset frequency threshold range may also be inconsistent with the first preset frequency threshold range. Preferably, the second preset frequency range may be smaller than the first preset frequency range. In addition, the second preset frequency range may also be a frequency range suitable for other plasma semiconductor processes, which is also covered within the protection scope of the present invention.

[0151] If the matrix element values ​​around the center point satisfy 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 value, it indicates that the pre-selected matching value is not only accurate, but also has good fault tolerance and stability, and can adapt to dynamic load changes that may occur in the process, and is therefore suitable as the optimal matching condition.

[0152] This step of verifying the best match value avoids the need to re-match through the matcher every time the chamber load changes, thereby reducing the negative impact of frequent adjustments on process stability. The error tolerance range of the best match value ensures the stability of the load conditions during the process and improves the reliability and repeatability of process operations. In addition, the error tolerance of the best match value enables it to adapt to slight changes in the chamber load without frequent adjustments, greatly improving process efficiency and quality.

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

[0154] by Figure 5 Taking the second result as an example, taking the Tune / Match value 51 / 50 as the center point, the element value data in the surrounding 3×3 matrix range meets the conditions that the reflected power is equal to 0, and the difference between the output frequency and the preset target frequency value 13.56MHz is within ±0.5MHz, then the pre-selected matching value is considered to be the best matching value;

[0155] by Figure 6 Taking 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, the Tune / Match value 50 / 49 satisfies the reflected power equal to 0, but the output frequency 15.66MHz is too large compared to the preset target frequency value 13.56MHz, exceeding the range of 0.5MHz, and it is considered that the pre-selected matching value is not the best matching value.

[0156] If the matrix range is less than 3×3, for example, the result is Figure 4 If the 2×2 matrix shown is not the best match value, the pre-selected match value is considered not to be the best match value, and the next suitable pre-selected match value is searched for.

[0157] If the matrix range is greater than 3×3 (ie, N>3), the center position of the matrix is ​​not unique, and a point whose output frequency is closest to the preset target frequency value is selected from the four points in the center as the judgment basis. If there are multiple closest points, they are judged in turn.

[0158] by Figure 7Take the fourth result of as an example, the matrix range is 4×4. First, from 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 that is closest to the preset target frequency value as the center point. Then, with the point of Tune / Match value 51 / 50 as the center point, construct a 3×3 matrix range, and check again whether the element values ​​in the matrix range meet the following conditions:

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

[0160] The 3×3 matrix formed by the Tune / Match value 51 / 50 satisfies the above conditions, and the pre-selected matching value is considered to be the best matching value. If the above conditions are not met, continue to search for the next suitable pre-selected matching value. If all pre-selected matching values ​​do not meet the requirements, return to step S1.

[0161] It should be understood that Figure 7 As a result, the above checking process may be unnecessary, because the center point is located at (one of) the centers of the 4×4 matrix, and there must be a 3×3 matrix range around the point that satisfies the above conditions.

[0162] In some embodiments, among the pre-selected matching values ​​in a matrix range of 4×4, there are two or more best matching values ​​in the central four points;

[0163] It should be noted that in the above step S7, if the current pre-selected matching value does not meet the optimal matching condition, the next pre-selected matching value is selected for judgment. If all pre-selected matching values ​​do not meet the condition, the input step size and step size 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 the matrix matching method according to the present invention can find at least one optimal matching value for the matcher. In some embodiments, there are multiple optimal matching values, which is not limited by the present invention.

[0165] When determining the best matching condition, the specified range around the center point can adopt a variety of different shapes. Although in the present embodiment, a square matrix (such as a 3×3 matrix) is used as the judgment range, and it is considered to be an ideal method, in fact, other shapes (such as rectangles, rings, and even irregular shapes) can also be used for such judgments. These different shapes can also effectively determine whether the matching value meets the best matching condition. Therefore, shapes other than 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 step S7, the method further includes:

[0167] The semiconductor process operation is performed using the first adjustable capacitance parameter and the second adjustable capacitance parameter corresponding to the best matching value as fixed parameters.

[0168] The Tune and Match values ​​corresponding to the best matching values ​​are written into the process parameters so that the matcher 20 outputs these values ​​in a fixed manner during the subsequent process. Running the process in a fixed mode can significantly improve the stability of the process operation and increase production efficiency.

[0169] Furthermore, based on the automatically generated matrix, users can also manually adjust the matrix diagram to find the best matching value and further improve the matching accuracy.

[0170] The step S3 further comprises:

[0171] The first adjustable capacitor parameter (Tune value) and / or the second adjustable capacitor parameter (Match value) in the matrix are manually adjusted and changed, and the corresponding reflected power and output frequency values ​​are recorded as the matrix element values ​​at the corresponding positions, and a matrix matching diagram is generated based on all the matrix element value data.

[0172] When the manual mode is adopted, 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 result. The action 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 adjust the Tune and Match values ​​in an arithmetic progression, with the output match value as the center, set the step size and step interval (tolerance), and thus construct a similar Figure 3 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 RF 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 that the energy transfer efficiency in the process is maximized.

[0176] Through manual adjustment, users can fine-tune matching parameters according to actual process requirements, thereby improving matching accuracy and ensuring the stability and accuracy of 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 from those illustrated and described herein or not illustrated and described herein but understandable to those skilled in the art.

[0178] The present invention provides an impedance matching method and system based on a matrix matching diagram, which accurately identifies the optimal matching parameters of an impedance matcher through a matrix scanning method and adapts to impedance changes under different process conditions. It not only effectively reduces the reflected power loss, but also ensures 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 claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" 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 directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0181] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0182] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[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, data, instructions, commands, information, signals, bits, symbols, and chips cited throughout the above description may be represented by voltage, current, 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 logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or a combination of the two. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. The technician may implement the described functionality in different ways for each specific application, but such implementation decisions should not be interpreted as resulting in a departure from the scope of the present invention.

[0185] The various illustrative logic modules and circuits described in conjunction with the embodiments disclosed herein may 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, a plurality of microprocessors, one or more microprocessors in cooperation with a DSP core, or any other such configuration.

[0186] The above embodiments are provided for persons familiar with the art to implement or use the present invention. Personnel familiar with 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 to the above embodiments, but should be the maximum scope of the innovative features mentioned in the claims.

Claims

1. A method for impedance matching based on a matrix matching diagram, characterized in that: A matcher is used to adjust the impedance matching between the radio frequency power supply and the cavity load in the plasma processing equipment, wherein the matcher comprises at least a first adjustable capacitor and a second adjustable capacitor; The method comprises the following steps: Starting the radio frequency power supply, setting a matching value as an initial point, wherein the matching value is a set of a first adjustable capacitance parameter and a second adjustable capacitance parameter; A matrix is ​​configured with the initial point as the scanning starting point, wherein the rows and columns of the matrix are respectively composed of the first adjustable capacitance parameter and the second adjustable capacitance parameter; Start a matrix scanning operation, change the first adjustable capacitance parameter and / or the second adjustable capacitance parameter value in the matrix in turn, and record the corresponding reflected power and output frequency value as the element value of the corresponding matrix position; Generate a matrix matching graph based on all matrix element value data; Determine whether each element value data in the matrix matching diagram meets the preset judgment condition. If the preset judgment condition is met, the current element value data is used as the pre-selected matching value. If all element value data do not meet the preset judgment condition, reset the initial point and start the matrix scan. The preset judgment condition is related to the reflected power value and the output frequency value. Generate a pre-selected matching value set from all pre-selected matching values; Determine whether each pre-selected matching value in the pre-selected matching value set meets the best matching condition. If the best matching condition is met, the current pre-selected matching value is used as the best matching value. If all pre-selected matching values ​​do not meet the best matching condition, reset the initial point and start matrix scanning, and repeat the above steps. The optimal matching condition is related to element value data surrounding the preselected matching value.

2. The impedance matching method based on the matrix matching diagram according to claim 1, characterized in that: The preset judgment conditions at least include: 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 comprises: If the current element value data satisfies 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 pre-selected matching value.

3. The impedance matching method based on the matrix matching diagram according to claim 1, characterized in that: The preset determination condition includes at least a first determination condition and a second determination 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 comprises: Determine whether each element value data in the matrix matching graph satisfies a first determination condition, select the element value data satisfying the first determination condition as a first determination matching value, and generate a first determination matching value set from all the first determination matching values; It is judged whether each element value data in the first determination matching value set satisfies the second determination condition, and the element value data satisfying the second determination condition is selected as the pre-selected matching value.

4. The impedance matching method based on a matrix matching diagram 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 reflected power is equal to 0, and the difference between the output frequency and the preset target frequency value is within a second preset frequency threshold range.

5. The impedance matching method based on the matrix matching diagram according to claim 4, characterized in that: The specified range around the center point forms a matrix consisting of N rows and N columns of matrix element values, where N is greater than or equal to 3.

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

7. The impedance matching method based on the matrix matching diagram according to claim 6, characterized in that: If the preset judgment condition is not met, the input step size and step size interval of the matrix scan are reset and the matrix scan is started; and / or If the optimal matching condition is not met, the input step size and step size interval of the matrix scan are reset and the matrix scan is started.

8. The impedance matching method based on a matrix matching diagram according to claim 1, characterized in that: 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: The first adjustable capacitance parameter and / or the second adjustable capacitance parameter value in the matrix is ​​adjusted and changed manually, and the corresponding reflected power and output frequency values ​​are recorded as element values ​​of the corresponding matrix positions.

9. The impedance matching method based on a matrix matching diagram according to claim 1, characterized in that: After the step of taking the current pre-selected matching value as the best matching value, the method further comprises: The semiconductor process operation is performed using the first adjustable capacitance parameter and the second adjustable capacitance parameter corresponding to the best matching value as fixed parameters of the matcher.

10. The impedance matching method based on a matrix matching diagram according to any one of claims 2 to 4, characterized in that: The preset target frequency value is a target ignition frequency.

11. An impedance matching system based on a matrix matching diagram, characterized in that: Including RF power supply, matching device, controller and cavity load: The radio frequency power supply is used to provide radio frequency energy; The matcher is located between the RF power supply and the cavity load, and is used to adjust the impedance matching between the RF power supply and the cavity load; The matcher at least includes a first adjustable capacitor and a second adjustable capacitor; The controller is connected to the matcher and is used to control the matcher to perform the impedance matching method based on the matrix matching diagram according to any one of claims 1 to 10; The chamber load is used for performing semiconductor processes.

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

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

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