Impedance matching method, impedance matcher and semiconductor process equipment

Abstract

The application provides an impedance matching method, an impedance matching device and a semiconductor process equipment, and switches the control mode of the impedance matching device to an automatic mode or a manual mode based on the real-time data of the reflected power and the reflection coefficient of the radio frequency power source, adopts the manual mode when the glow is not started and when the glow is started to avoid problems such as slow matching time and inconsistent matching time, and adopts the manual mode after the plasma is stable to avoid plasma fluctuation or extinction caused by over-regulation of the impedance matching device due to slight fluctuation of the chamber impedance, so as to improve the impedance matching efficiency and the plasma stability.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to an impedance matching method, an impedance matching device, and semiconductor process equipment. Background Art

[0002] Inductively coupled plasma (ICP) sources are used in a variety of fields within semiconductor equipment manufacturing, including etching, thin film deposition, and ion implantation. Their primary principle is that radio frequency current flowing through a coil generates an electromagnetic field within the chamber, exciting the gas to form a plasma. A bias voltage controls the ion bombardment energy. When using an ICP source, an automatic impedance matcher is required between the power supply and the plasma reaction chamber. This impedance matcher automatically adjusts parameters such as the variable capacitance based on the actual impedance of the plasma reaction chamber, ensuring an input impedance of 50Ω, maximizing power supply output efficiency, and ensuring stable plasma discharge.

[0003] The plasma ignition process mainly includes two parts. The first process is that the plasma goes from non-ignition to ignition, and the impedance suddenly changes. This process is very short, and the impedance matcher may not be able to fully respond to the change in chamber impedance before entering the next ignition process. The second process is that after the plasma is generated, the impedance matcher gradually completes the impedance matching, and the plasma discharge process gradually stabilizes.

[0004] Impedance matchers generally have two basic control modes: automatic mode and manual mode. In the Auto mode, the time required for impedance matching depends on the impedance matching algorithm and the preset position selection. Since sensors are used for detection, slight differences in the initial plasma state will also lead to different matching processes. The sensor accuracy also affects the final matching time, resulting in inconsistent matching time. After the plasma stabilizes, if there are small fluctuations in the chamber, it may cause the impedance matcher to over-adjust, resulting in poor plasma stability. In the Manual mode, the capacitance value of the matching circuit in the impedance matcher is fixed at a certain set value and cannot be automatically adjusted as the plasma state changes. This may result in problems such as the inability to achieve impedance matching or the matching time being too long. Summary of the Invention

[0005] The present invention solves the problems of low impedance matching efficiency and poor plasma stability in a single control mode of an impedance matcher in an existing semiconductor process.

[0006] To solve the above problems, an embodiment of the present invention provides an impedance matching method, which is applied to semiconductor process equipment. The semiconductor process equipment includes a radio frequency power supply, an impedance matcher and a process chamber. The radio frequency power supply loads radio frequency power to the process chamber through the impedance matcher. The method includes: obtaining a reflection coefficient and reflected power of the radio frequency power supply; the reflection coefficient is the ratio of the reflected power to the incident power; if the reflection coefficient is greater than or equal to a preset coefficient threshold and the reflected power is greater than a preset power threshold, setting the impedance matcher to manual mode and setting the parameter value of the parameter adjustable device of the impedance matcher to a preset ignition parameter value.

[0007] As a feasible implementation manner, it also includes: if the reflection coefficient is less than the preset coefficient threshold and the reflection power is less than or equal to the preset power threshold, the impedance matcher is set to manual mode to keep the parameter value of the parameter adjustable device of the impedance matcher unchanged.

[0008] As a feasible implementation manner, it also includes: if the reflection coefficient is greater than or equal to the preset coefficient threshold and the reflected power is less than or equal to the preset power threshold, or the reflection coefficient is less than the preset coefficient threshold and the reflected power is greater than the preset power threshold, the impedance matcher is set to automatic mode.

[0009] As a feasible implementation manner, the impedance matcher automatically adjusts the parameter value of the parameter-adjustable device based on a preset matching algorithm in the automatic mode until impedance matching is achieved.

[0010] As a feasible implementation manner, obtaining the reflection coefficient and reflected power of the RF power supply includes: reading circuit parameters based on a sensor of the RF power supply, and determining the reflected power and the incident power according to the circuit parameters; and calculating the reflection coefficient based on the reflected power and the incident power.

[0011] As a feasible implementation manner, the preset ignition parameter value is a parameter value of a static impedance matching position of the process chamber, or a parameter value corresponding to the static impedance matching position of the process chamber.

[0012] As a feasible implementation manner, the parameter-adjustable device of the impedance matcher includes at least two variable capacitors, and the parameter value is the capacitance value of the variable capacitor.

[0013] As a feasible implementation manner, it also includes: after a predetermined period of time, returning to execute the step of obtaining the reflection coefficient and reflected power of the RF power supply, and executing the step of setting the impedance matcher to manual mode or automatic mode according to the reflection coefficient and the reflected power.

[0014] The embodiment of the present application provides an impedance matcher for a radio frequency power supply, which is applied to a semiconductor process equipment, the radio frequency power supply loads radio frequency power to a process chamber of the semiconductor process equipment through the impedance matcher, and the impedance matcher comprises: an impedance matching circuit comprising at least two parameter adjustable devices; and a controller configured to acquire a reflection coefficient and a reflected power of the radio frequency power supply, wherein the reflection coefficient is a ratio of the reflected power to incident power; if the reflection coefficient is greater than or equal to a preset coefficient threshold value and the reflected power is greater than a preset power threshold value, the impedance matcher is set to a manual mode and parameter values of the parameter adjustable devices of the impedance matcher are set to preset ignition parameter values; or

[0015] The controller is configured to, if the reflection coefficient is less than the preset coefficient threshold value and the reflected power is less than or equal to the preset power threshold value, set the impedance matcher to the manual mode to keep the parameter values of the parameter adjustable devices of the impedance matcher unchanged; or

[0016] The controller is configured to, if the reflection coefficient is greater than or equal to the preset coefficient threshold value and the reflected power is less than or equal to the preset power threshold value, or the reflection coefficient is less than the preset coefficient threshold value and the reflected power is greater than the preset power threshold value, set the impedance matcher to an automatic mode.

[0017] The embodiment of the present application provides a semiconductor process equipment, which comprises a process chamber, a radio frequency power supply and the above-mentioned impedance matcher, and the radio frequency power supply loads radio frequency power to the process chamber through the impedance matcher.

[0018] The impedance matching method, the impedance matcher and the semiconductor process equipment provided by the embodiment of the present application switch the control mode of the impedance matcher to the automatic mode or the manual mode based on the real-time data of the reflected power and the reflection coefficient of the radio frequency power supply, the manual mode is adopted when ignition is not started and when ignition is started to avoid problems such as slow matching time and inconsistent matching time, and the manual mode is adopted after the plasma is stable to avoid plasma fluctuation or extinction caused by over-regulation of the impedance matcher due to slight fluctuation of the chamber impedance, so that the impedance matching efficiency and the plasma stability are improved. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of the provided drawings.

[0020] Figure 1A schematic diagram of an impedance matching circuit of a prior art matching device is shown;

[0021] Figure 2 A schematic flow chart of an impedance matching method according to an embodiment of the present application is shown;

[0022] Figure 3 A schematic diagram of a comparison of reflected power between the prior art and the present embodiment is shown;

[0023] Figure 4 A flow chart of a method of switching the control mode of the capacitance of an impedance matching device based on the reflection coefficient and the reflected power of a power supply according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0024] In order to make the above objectives, features and advantages of the present application more obvious and understandable, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0025] Transmission line theory indicates that when the characteristic impedance of a power supply is different from the load impedance, the output power of the radio frequency power supply will be lost, the output efficiency cannot be maximized, energy is wasted, the power supply itself can be damaged, and even local heat can be too high to cause a fire. Therefore, during the use of a plasma source, an automatic impedance matching device needs to be added between the power supply and the plasma reaction chamber. The impedance matching device can automatically adjust parameters such as variable capacitance according to the actual impedance of the plasma reaction chamber, so that the input impedance is equal to 50Ω, the output efficiency of the power supply is maximized, and the plasma is stably discharged.

[0026] The performance of the impedance matching device directly affects the plasma density, energy, spatial distribution and other parameters in the reaction chamber, thereby affecting the process results. The matching speed of the impedance matching device is an important parameter index in the matching performance. The faster the matching speed, the faster the plasma reaches stability, which is beneficial to shorten the total time of the wafer process and improve the efficiency. And when the plasma is stable, the capacitance position of the impedance matching device is relatively stable. If the impedance matching device is still fluctuating after the plasma is stable, the stability of the discharge system will be affected.

[0027] The plasma ignition process in the plasma reaction chamber mainly includes two parts: the first process is from the unignition of the plasma to the ignition, and the impedance changes suddenly. This process is very short, and the impedance matching device may not be able to completely respond to the change of the chamber impedance to enter the next process of ignition; the second process is that after the plasma is generated, the impedance matching device gradually completes the impedance matching, and at the same time, the plasma discharge process is also gradually stabilized.

[0028] Impedance matchers generally have two basic control modes: Auto and Manual. In Auto mode, different capacitance values ​​(generally expressed as a percentage of the maximum capacitance value) correspond to different capacitance positions. Before starting, the impedance matcher calls a preset capacitance position to obtain the desired preset capacitance value. In Manual mode, the impedance matcher cannot use the automatic matching function. The capacitance value is fixed at a certain set value. When a new capacitance value is set, its value will change. Calling the capacitance position in this mode is not effective. In Auto mode, the impedance matcher first calls a preset position. After the power supply loads power to the chamber, the impedance matcher's sensor detects the voltage amplitude and phase size in the circuit. Based on the detected data, after analysis by the impedance matcher algorithm, the motor controls the change in the value of the variable capacitors C1, C2, and C3 to match the impedance to 50Ω, completing the matching process.

[0029] When the impedance matcher is in automatic mode, the time required for impedance matching depends on the impedance matcher algorithm and the preset position selection. Furthermore, due to the use of sensor detection, slightly different initial plasma states will also lead to different matching processes. The sensor accuracy also affects the final matching time, resulting in inconsistent matching times. Due to algorithm limitations, when the preset position is poor, the matching time can reach 4 to 5 seconds, significantly impacting the stability of the process results. When the plasma stabilizes, the impedance matcher remains in Auto mode. If there are minor fluctuations in the chamber, this may cause the impedance matcher to over-adjust, resulting in poor plasma stability.

[0030] Figure 1 This diagram shows an impedance matching circuit for a matching device in the prior art. Capacitors C1 and C2 are used for impedance matching, capacitors C3 and C4 are used to distribute the current ratio between the two output terminals, and capacitor C5 is used to adjust the inductance of the coil. In actual matching, capacitors C4 and C5 are typically fixed. Impedance matching can be achieved by simply changing the capacitance values ​​of C1 and C2, or by simultaneously adjusting the current ratio and impedance matching by changing the capacitance values ​​of C1, C2, and C3. The RF input port is connected to a power supply.

[0031] There is no specific limitation on the number of capacitors involved in capacitance value adjustment in the impedance matcher. For example, the number of capacitors involved in capacitance value adjustment can be 2 or more. Figure 1 As shown, the impedance matcher may include a first capacitor C1 and a second capacitor C2.

[0032] The power of the power supply is input to the coil of the process chamber through the output ends out1 and out2, and is output to the ground through the return ends return1 and return2 to form a loop. The coil couples energy into the chamber through electromagnetic induction. This matching device has two input coil branches (out1 and out2), and then forms a loop by grounding (return1 and return2), that is, it has two branches for energy coupling with the chamber, and is called a double-output matching device.

[0033] In the prior art described above, it is recorded that the initial position of the variable capacitor determines the initial impedance value of the reaction chamber, which affects the difficulty of plasma ignition. Therefore, in actual use, the time required for plasma to reach stability under different initial capacitor positions is counted, and the initial capacitor position that can make the plasma reach stability the fastest is selected as the preset position.

[0034] The prior art described above can find a capacitor position that can make the chamber ignite, but the plasma after ignition has poor anti-interference ability, and the reflected power has large fluctuations.

[0035] The embodiment of the present application provides an impedance matching method, which can greatly optimize the stability process of the plasma and the control mode of the impedance matching device after the plasma is stable, is beneficial to the consistency of the plasma-related process, and can avoid the problems of low impedance matching efficiency caused by the inconsistency of the matching time, the long matching time and the over-adjustment of the impedance matching device caused by the single algorithm limitation of the impedance matching device.

[0036] Compared with the prior art described above, the control method provided by the embodiment of the present application can switch the control mode of the matching device based on the reflected power and the reflection coefficient read by the sensor of the power supply. In different scenarios, the matching device can be in Auto mode or Manual mode. The problem that the reflected power read by the sensors of the matching device and the power supply is different can be avoided (in fact, the value read by the power supply is generally taken as a reference). By judging the plasma stability after ignition through the reflection coefficient and the reflected power, the matching device is set to manual mode, which can increase the stability of the plasma system and prevent the abnormal phenomena of long matching time and capacitor over-adjustment when the matching device re-performs automatic matching.

[0037] Figure 2 A schematic flowchart of an impedance matching method in the embodiment of the present application is shown. The method is applied to a semiconductor process equipment, which includes a radio frequency power supply, an impedance matching device and a process chamber, and the radio frequency power supply loads radio frequency power to the process chamber through the impedance matching device. The method includes:

[0038] S202: Obtain the reflection coefficient and reflected power of the RF power source. The reflection coefficient is the ratio of the reflected power to the incident power. The incident power refers to the sum of all power output to the capacitor plate or inductor coil, including the effective power ultimately absorbed by the load and the reflected power that is not absorbed.

[0039] The circuitry within the RF power supply includes sensors. When the RF power supply begins to apply RF power to the process chamber via the impedance matcher, it can measure the parameters of the circuitry in real time. Optionally, the RF power supply's sensors read the circuit parameters and determine the reflected power and incident power based on these circuit parameters. The reflection coefficient is then calculated based on the reflected power and incident power. These circuit parameters include amplitude, phase, voltage, and current.

[0040] S204: Compare the reflection coefficient with a preset coefficient threshold, and compare the reflection power with a preset power threshold.

[0041] S206 , if the reflection coefficient is greater than or equal to the preset coefficient threshold and the reflection power is greater than the preset power threshold, setting the impedance matcher to a manual mode and setting the parameter value of the parameter-adjustable device of the impedance matcher to a preset ignition parameter value.

[0042] The preset coefficient threshold and preset power threshold are user-adjustable parameters, and the parameter-adjustable components include adjustable capacitors and / or adjustable inductors. A larger reflection coefficient indicates a non-ignition state, and this parameter can be set according to process requirements; a greater reflection power indicates a greater deviation from the matching position, and this parameter can be set according to actual process needs. Therefore, if the reflection coefficient is greater than or equal to the preset coefficient threshold and the reflection power is greater than or equal to the preset power threshold, indicating that the current plasma has not ignited, the impedance matcher can be set to manual mode to put the impedance matcher in a controllable state, and the parameter values ​​of the parameter-adjustable components of the impedance matcher can be set to the preset ignition parameter values.

[0043] The preset ignition parameter value is a parameter value corresponding to the static impedance matching of the process chamber, or a ignition point parameter value corresponding to the static impedance matching state. For example, if the parameter-adjustable device is an adjustable capacitor, the capacitance position of the adjustable capacitor can be set to the ignition point (the ignition point at or near the chamber static impedance matching position).

[0044] Exemplarily, the parameter-adjustable device of the impedance matcher includes at least two variable capacitors, and the parameter value is the capacitance value of the variable capacitor.

[0045] S208 : If the reflection coefficient is less than the preset coefficient threshold and the reflection power is less than or equal to the preset power threshold, the impedance matcher is set to a manual mode to keep the parameter value of the parameter adjustable component of the impedance matcher unchanged.

[0046] A small reflection coefficient and a small reflected power indicate that the system is in a matching state. If the impedance matcher is in automatic state, the capacitor position will be adjusted when the impedance matcher detects a small change in impedance. When the capacitor position is adjusted by a large amplitude, the impedance matcher will be over-adjusted, resulting in system mismatch, and the reflected power and reflection coefficient will increase instead.

[0047] In this case, the impedance matcher can be set to manual mode to keep the parameter value of the parameter-adjustable device of the impedance matcher unchanged. Optionally, the parameter value of the parameter-adjustable device of the impedance matcher is set to the impedance matching parameter value. When plasma is generated in the process chamber, the reflection coefficient decreases rapidly, and the impedance matcher can be switched to automatic at this time. After plasma is generated, the impedance matcher can automatically match the impedance by an automatic matching method, and its final matching position is the impedance matching position. The parameter value of the impedance matcher corresponding to the impedance matching when the impedance matching is achieved is the above-mentioned impedance matching parameter value. Based on this, the above-mentioned method can also include the following steps: first, loading RF power to the process chamber through the impedance matcher, and performing impedance matching through the impedance matcher, and determining the current parameter value of the parameter-adjustable device when the impedance matching is achieved after the plasma is generated; then, the current parameter value is used as the impedance matching parameter value.

[0048] In this embodiment, by setting the impedance matcher to manual mode, it is possible to avoid plasma fluctuation or extinguishing caused by over-modulation of the impedance matcher when there is a slight fluctuation in chamber impedance after plasma stabilization.

[0049] S210 , if the reflection coefficient is greater than or equal to the preset coefficient threshold and the reflected power is less than or equal to the preset power threshold, or if the reflection coefficient is less than the preset coefficient threshold and the reflected power is greater than the preset power threshold, setting the impedance matcher to an automatic mode.

[0050] In the above situation, for example, when the chamber generates plasma but is not matched, the impedance matcher needs to operate in automatic mode to perform impedance matching.

[0051] It should be noted that the above-mentioned steps of obtaining the reflection coefficient and reflected power of the RF power supply, as well as the subsequent steps of determining the magnitude relationship of the above-mentioned parameters and setting the automatic mode or manual mode, are continuously performed while the RF power supply is loading RF power into the process chamber through the impedance matcher, thereby continuously controlling the impedance matcher. Optionally, after a certain interval, the above-mentioned steps are repeated once. Based on this, the above-mentioned method may further include: after a predetermined period of time, returning to the step of obtaining the reflection coefficient and reflected power of the RF power supply, and performing the step of setting the impedance matcher to manual mode or automatic mode based on the reflection coefficient and reflected power.

[0052] Optionally, in the manual mode, the parameter adjustable device keeps the parameter value unchanged. In the automatic mode, the impedance matching device automatically adjusts the parameter value of the parameter adjustable device until the impedance is matched based on the preset matching algorithm.

[0053] The impedance matching method provided by the embodiment of the application switches the control mode of the impedance matching device based on the real-time data of the reflected power and the reflection coefficient of the radio frequency power source, adopts the manual mode in the non-ignition state and the ignition state to avoid problems such as slow matching time and inconsistent matching time, and adopts the manual mode after the plasma is stable to avoid plasma fluctuation or extinction caused by over-adjustment of the impedance matching device due to slight fluctuation of the chamber impedance, thereby improving the impedance matching efficiency and the plasma stability.

[0054] The prior art controls the matching device by itself, adjusts the plurality of capacitors in the matching device to the stable capacitor value measured in the capacitor value determination stage, and only adjusts one capacitor from the ignition capacitor value to the stable capacitor value of the capacitor after the power source is started, thereby changing from the determination state before the power source is started to another determination state after the power source is started in the ignition process, and eliminating the time difference of automatic adjustment of the impedance of the matching device with the unknown initial capacitor value state as the starting point. The embodiment of the application controls the control mode switching of the matching device through the reflected power and the reflection coefficient of the power source, and can solve the problem caused by the sensor of the matching device in the prior art. Figure 3 The reflected power comparison diagrams of the prior art and the embodiment are shown. Figure 3 The left one in the figure is the incident power and the reflected power diagram of the prior art, and the other three are the incident power and the reflected power diagrams of the embodiment. As can be seen, under the prior art scheme, the reflected power fluctuates greatly between 0-200W, and correspondingly, the forward power also fluctuates to a certain extent, thereby causing unstable plasma, and further causing adverse effects on the wafer process. Under the scheme, the reflected power is stably fluctuated near 7W, 10W and 15W, respectively, and the stability is very good, and correspondingly, the forward power is basically constant, thereby causing the problem of the generated plasma, and further causing the wafer process to be stable.

[0055] The embodiment of the application gives a method for optimizing the matching process of the matching device based on the real-time reflection coefficient of the power source based on the impedance variation law in the plasma reaction chamber. The matching device does not need to automatically match the impedance in the initial ignition stage of the plasma and after the plasma is stable, and in the above two cases, the capacitor mode of the matching device can be controlled according to the reflection coefficient fed back by the power source to make the matching device in the Manual mode. When the chamber generates plasma but is not matched, the matching device needs to match the impedance in the automatic mode.

[0056] This method also avoids the problem of different reflected powers being read by different sensors in the matching unit and power supply (the power supply reading is generally used as a reference in practice). After determining stable plasma ignition using the reflection coefficient and reflected power, setting the matching unit to Manual mode can increase plasma system stability and prevent abnormalities such as long matching times and capacitance overshoot that can occur when the matching unit re-automatically matches.

[0057] The impedance matching point of the matchbox before plasma is generated differs significantly from the impedance matching point after plasma is generated. When plasma is not generated, the power supply reflection coefficient is usually high. In this case, it is desirable to put the matchbox in Manual mode to prevent the capacitor position from reaching an unnecessary matching position in Auto mode. In this case, the capacitor is controllable and can be set to the starting position.

[0058] When plasma is generated in the chamber, the reflection coefficient decreases rapidly. At this point, the matcher can be switched to Auto mode. Once plasma is generated, the matcher automatically performs impedance matching, with its final matching position being the impedance matching position. The present invention controls the capacitance control mode of the matcher using the power supply reflection coefficient, thus avoiding problems such as long matching times caused by inconsistencies in the final impedance matching point during plasma ignition and impedance matching.

[0059] Specifically, the power supply reflection coefficient = reflected power / incident power. After the power supply is loaded, the reflection coefficient is read in real time, and the reflected power is read. The impedance matching device capacitance control mode is controlled according to the reflected power and the reflection coefficient.

[0060] Figure 4 A flow chart of a method for switching an impedance matching device capacitance control mode based on a power supply reflection coefficient and reflected power provided by an embodiment of the present invention is shown, comprising the following steps:

[0061] S401: Determine whether the reflection coefficient is greater than or equal to a reflection coefficient threshold parameter a. If yes, execute S402; if not, execute S406.

[0062] Where a is a user-adjustable reflection coefficient threshold parameter. A large reflection coefficient indicates an unignited state. This threshold parameter can be set according to process requirements, for example, setting a = 0.4.

[0063] S402: Determine whether the reflected power is less than or equal to a reflected power threshold parameter b. If so, execute S405; if not, execute S403.

[0064] Where b is a user-adjustable reflection power threshold parameter. A higher reflection power indicates a greater deviation from the matching position. This threshold parameter can be set based on actual process requirements, for example, b = 20W.

[0065] S403: Set the impedance matching device to Manual mode.

[0066] When the power supply reflection coefficient ≥ a and the reflected power ≥ b, it indicates that the plasma has not yet ignited. In this case, the impedance matcher can be set to manual mode and the capacitor to the ignition point (the chamber's static impedance matching position or a ignition point near the matching position). Since there are two matching points during the pre-ignition and ignition phases, to prevent the impedance matcher's capacitor position from being affected by changes in the chamber impedance during the ignition phase, causing the matching path to become abnormal (uncontrollable), the impedance matcher can be set to manual mode to keep it in a controllable state.

[0067] S404 , setting the capacitance positions of the capacitors C1 and C2 .

[0068] S405, setting the impedance matching device to Auto mode.

[0069] When the power supply reflection coefficient is ≥a and the reflected power is ≤b, it means that the plasma or system is in an abnormal state and the impedance matcher is required to automatically perform impedance matching.

[0070] S406: Determine whether the reflected power is less than or equal to the reflected power threshold parameter b. If so, execute S407; if not, execute S408.

[0071] S407, setting the impedance matching device to Manual mode.

[0072] When the power supply reflection coefficient is less than a and the power supply reflected power is less than b, the system is in a matching state. If the impedance matcher is in Auto mode, the capacitor position will be adjusted when it detects slight impedance changes. Large adjustments to the capacitor position can cause the impedance matcher to overshoot, leading to system mismatch and increased reflected power and reflection coefficient. Setting the impedance matcher to Manual mode can avoid this phenomenon.

[0073] S408, setting the impedance matching device to Auto mode.

[0074] When the reflection coefficient is less than a and the reflection power is greater than b, the impedance matcher slightly deviates from the matching position. At this time, the impedance matcher can be placed in the Auto mode for automatic impedance matching.

[0075] After the above steps S404 , S405 , S407 and S408 , the process returns to the determination step S401 , thereby repeatedly executing the above steps S401 - S408 to continuously control the impedance matching box.

[0076] The embodiment of the present invention controls the control mode of the impedance matcher based on the real-time data of the power supply reflection coefficient and the reflected power, which can solve the problems of slow matching time and inconsistent matching time caused by the presence of two matching points when the plasma is not ignited and when it is ignited; the control mode of the impedance matcher is controlled based on the real-time data of the power supply reflection coefficient and the reflected power, which can avoid plasma fluctuation or extinguishing caused by overmodulation of the impedance matcher when there is a slight fluctuation in the chamber impedance after the plasma is stabilized; the power supply and the impedance matcher can be linked to achieve mutual synergy, which is conducive to precise matching control and improved plasma stability.

[0077] An embodiment of the present invention provides an impedance matcher for a radio frequency power supply, which is applied to semiconductor process equipment. The radio frequency power supply loads radio frequency power to a process chamber of the semiconductor process equipment through the impedance matcher. The impedance matcher includes: an impedance matching circuit including at least two parameter-adjustable devices; a controller for obtaining a reflection coefficient and a reflected power of the radio frequency power supply; the reflection coefficient is a ratio of the reflected power to the incident power; if the reflection coefficient is greater than or equal to a preset coefficient threshold and the reflected power is greater than a preset power threshold, the impedance matcher is set to a manual mode and the parameter value of the parameter-adjustable device of the impedance matcher is set to a preset ignition parameter value; or

[0078] The controller is configured to set the impedance matcher to a manual mode to maintain a parameter value of a parameter-adjustable device of the impedance matcher unchanged if the reflection coefficient is less than a preset coefficient threshold and the reflection power is less than or equal to a preset power threshold; or

[0079] The controller is configured to set the impedance matcher to an automatic mode if the reflection coefficient is greater than or equal to a preset coefficient threshold and the reflection power is less than or equal to a preset power threshold, or if the reflection coefficient is less than the preset coefficient threshold and the reflection power is greater than the preset power threshold.

[0080] An embodiment of the present invention provides a semiconductor process equipment, including a process chamber, a radio frequency power supply and the above-mentioned impedance matcher; the radio frequency power supply loads radio frequency power to the process chamber through the above-mentioned impedance matcher.

[0081] The impedance matcher for RF power supply and semiconductor process equipment provided in this embodiment can implement each process in the embodiment of the above-mentioned impedance matching method and can achieve the same technical effect. To avoid repetition, they are not described here.

[0082] This embodiment further provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the various processes of the above-described impedance matching method embodiment and achieves the same technical effects. To avoid repetition, the details are omitted here. The computer-readable storage medium may be, for example, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0083] Of course, those skilled in the art will understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by a computer program instruction control device, and the computer program can be stored in a computer-readable storage medium. When the computer program is executed, it may include processes such as the above-mentioned method embodiments, wherein the storage medium may be a memory, a disk, an optical disk, etc.

[0084] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

[0085] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0086] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference will be made to the common and similar parts between the various embodiments. Regarding the semiconductor process equipment disclosed in the embodiments, since it corresponds to the impedance matching method disclosed in the above embodiments, the description is relatively simple. For relevant details, refer to the method description.

[0087] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An impedance matching method, applied to semiconductor process equipment, wherein the semiconductor process equipment includes a radio frequency power supply, an impedance matcher, and a process chamber, wherein the radio frequency power supply applies radio frequency power to the process chamber through the impedance matcher, characterized in that: The method comprises: Obtaining a reflection coefficient and a reflected power of the radio frequency power source; the reflection coefficient is a ratio of the reflected power to the incident power; If the reflection coefficient is greater than or equal to a preset coefficient threshold and the reflection power is greater than a preset power threshold, the impedance matcher is set to a manual mode and the parameter value of the parameter adjustable device of the impedance matcher is set to a preset ignition parameter value.

2. The method according to claim 1, characterized in that Also includes: If the reflection coefficient is less than the preset coefficient threshold and the reflection power is less than or equal to the preset power threshold, the impedance matcher is set to a manual mode to keep the parameter value of the parameter adjustable component of the impedance matcher unchanged.

3. The method according to claim 1, characterized in that Also includes: If the reflection coefficient is greater than or equal to the preset coefficient threshold and the reflected power is less than or equal to the preset power threshold, or if the reflection coefficient is less than the preset coefficient threshold and the reflected power is greater than the preset power threshold, the impedance matcher is set to automatic mode.

4. The method according to claim 3, characterized in that In the automatic mode, the impedance matcher automatically adjusts the parameter value of the parameter-adjustable device based on a preset matching algorithm until impedance matching is achieved.

5. The method according to claim 1, wherein The obtaining of the reflection coefficient and the reflection power of the radio frequency power source includes: Reading circuit parameters based on a sensor of the radio frequency power supply, and determining the reflected power and the incident power according to the circuit parameters; The reflection coefficient is calculated according to the reflected power and the incident power.

6. The method according to claim 1, characterized in that The preset ignition parameter value is a parameter value of a static impedance matching position of the process chamber, or a parameter value corresponding to the static impedance matching position of the process chamber.

7. The method according to claim 1, characterized in that The parameter-adjustable device of the impedance matcher includes at least two variable capacitors, and the parameter value is the capacitance value of the variable capacitor.

8. The method according to any one of claims 1 to 7, characterized in that Also includes: After a predetermined time period, the method returns to the step of obtaining the reflection coefficient and the reflected power of the RF power source, and performs the step of setting the impedance matching device to a manual mode or an automatic mode according to the reflection coefficient and the reflected power.

9. An impedance matcher for a radio frequency power supply, applied to semiconductor processing equipment, wherein the radio frequency power supply loads radio frequency power to a process chamber of the semiconductor processing equipment through the impedance matcher, characterized in that: The impedance matching box includes: An impedance matching circuit comprising at least two parameter-adjustable devices; A controller, configured to obtain a reflection coefficient and a reflected power of the RF power source; the reflection coefficient being a ratio of the reflected power to the incident power; and if the reflection coefficient is greater than or equal to a preset coefficient threshold and the reflected power is greater than a preset power threshold, setting the impedance matcher to a manual mode and setting a parameter value of a parameter-adjustable device of the impedance matcher to a preset ignition parameter value; or The controller is configured to set the impedance matcher to a manual mode to maintain a parameter value of a parameter-adjustable component of the impedance matcher unchanged if the reflection coefficient is less than the preset coefficient threshold and the reflected power is less than or equal to the preset power threshold; or The controller is configured to set the impedance matcher to an automatic mode if the reflection coefficient is greater than or equal to the preset coefficient threshold and the reflected power is less than or equal to the preset power threshold, or if the reflection coefficient is less than the preset coefficient threshold and the reflected power is greater than the preset power threshold.

10. A semiconductor process equipment, characterized in that: comprising a process chamber, a radio frequency power supply, and the impedance matching device according to claim 9; The radio frequency power supply applies radio frequency power to the process chamber through the impedance matcher.

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