Radio frequency power supply control method in dual-frequency plasma processing

Abstract

The invention provides a radio frequency power supply control method in double-frequency plasma processing, and belongs to the technical field of semiconductor device processing. The radio frequency power supply control method in the double-frequency plasma processing comprises the steps that real-time power of a high-frequency radio frequency generator and real-time power of a low-frequency radio frequency generator are collected; the actual offset condition of the power in each target process can be obtained, and the power of the corresponding radio-frequency power supply can be adjusted under the condition that the plasma parameters do not meet the processing requirements, so that the radio-frequency power supply can compensate the power fluctuation in time, the plasma parameters can continuously meet the wafer processing requirements, the stability is kept, and the processing efficiency is improved. And control and stability of the machining process are facilitated, and machining defects or quality fluctuation caused by unstable plasma parameters are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor device processing, and in particular to a method for controlling a radio frequency power supply in dual-frequency plasma processing. Background Art

[0002] Plasma etching equipment is widely used in existing semiconductor processing to process semiconductor wafers to obtain microscopic semiconductor devices and conductor connections. Common plasma etching equipment is capacitive coupling and inductive coupling etcher, which generally have two radio frequency generators, one of which is a high-frequency radio frequency generator used to ionize the reaction gas introduced into the reaction chamber to generate plasma, and the other is a low-frequency radio frequency generator used to control the energy of the ions incident on the wafer surface.

[0003] In dual-frequency plasma processing, the existing technology sets a pair of frequency combinations according to different process requirements, and sets the power of two RF power supplies for different processing stages, thereby forming a control strategy for the two RF power supplies. In the existing technology, the control strategy for the two RF power supplies required by the processing equipment has been determined before the processing begins. However, in the actual processing process, due to the unstable output performance of the RF power supply itself and other unstable reasons such as the unevenness of the reaction chamber space, the pre-set control strategy cannot achieve the best processing effect. Summary of the invention

[0004] The present invention provides a method for controlling a radio frequency power supply in dual-frequency plasma processing, which is used to solve the defect of radio frequency power supply power deviation in the prior art and achieve the effect that plasma parameters can continuously meet the requirements of wafer processing.

[0005] The present invention provides a method for controlling a radio frequency power supply in dual-frequency plasma processing, wherein the radio frequency power supply comprises a high-frequency radio frequency generator and a low-frequency radio frequency generator, wherein the high-frequency radio frequency generator is used to ionize a reaction gas introduced into a reaction chamber to generate plasma, and the low-frequency radio frequency generator is used to control the energy of ions incident on a wafer surface, and the method comprises:

[0006] When the high-frequency RF generator is discharged according to the first preset power under the target process, the real-time power of the high-frequency RF generator is collected;

[0007] During the process of the low-frequency RF generator discharging according to the second preset power under the target process, collecting the real-time power of the low-frequency RF generator;

[0008] Collecting plasma parameters at each target position in the wafer processing space, and analyzing the plasma parameters at each target position to determine whether the parameters of the plasma for wafer processing meet the processing requirements;

[0009] In the case where the parameters of the plasma processed for the wafer do not meet the processing requirements, determining whether the real-time power of the high-frequency RF generator deviates from the first preset power, and determining whether the real-time power of the low-frequency RF generator deviates from the second preset power;

[0010] When the real-time power of the high-frequency RF generator deviates from the first preset power, the high-frequency RF generator is controlled to discharge according to a third preset power, and / or when the real-time power of the low-frequency RF generator deviates from the second preset power, the high-frequency RF generator is controlled to discharge according to a fourth preset power.

[0011] According to a method for controlling RF power supply in dual-frequency plasma processing provided by the present invention, the third preset power is obtained based on the first preset power and the fluctuation range of the real-time power of the high-frequency RF generator, and the fourth preset power is obtained based on the second preset power and the fluctuation range of the real-time power of the low-frequency RF generator.

[0012] According to a method for controlling a radio frequency power supply in dual-frequency plasma processing provided by the present invention, the third preset power is determined by the following method:

[0013] According to the real-time power of the high-frequency radio frequency generator, a first power curve of the real-time power of the high-frequency radio frequency generator varying with time is obtained;

[0014] Based on the first power curve, a first ratio of the time corresponding to the power fluctuation range of the high-frequency RF generator to the discharge time of the high-frequency RF generator is identified; the power fluctuation range of the high-frequency RF generator is determined based on the power size and the power change rate when the high-frequency RF generator is discharged;

[0015] The third preset power is determined based on the first preset power and the first ratio.

[0016] According to a method for controlling a radio frequency power supply in dual-frequency plasma processing provided by the present invention, the fourth preset power is determined by the following method:

[0017] According to the real-time power of the low-frequency radio frequency generator, a second power curve of the real-time power of the low-frequency radio frequency generator varying with time is obtained;

[0018] Based on the second power curve, identifying a second ratio of the time corresponding to the power fluctuation range of the low-frequency RF generator to the discharge time of the low-frequency RF generator; the power fluctuation range of the low-frequency RF generator is determined based on the power size and the power change rate when the low-frequency RF generator is discharged;

[0019] The fourth preset power is determined based on the second preset power and the second ratio.

[0020] According to a method for controlling RF power supply in dual-frequency plasma processing provided by the present invention, the plasma parameters at each target position include at least one of plasma density, plasma distribution uniformity, plasma temperature and plasma pressure.

[0021] According to a method for controlling a radio frequency power supply in dual-frequency plasma processing provided by the present invention, the plasma parameters at each target position include the density of the plasma, and the plasma parameters at each target position are analyzed to determine whether the parameters of the plasma for wafer processing meet the processing requirements, including:

[0022] When the density of the plasma at the processing position of the wafer meets the processing requirements, the density of the plasma at each target position is averaged to obtain the average density of the plasma;

[0023] Determine whether the average plasma density meets the plasma density requirements.

[0024] According to a method for controlling a radio frequency power supply in dual-frequency plasma processing provided by the present invention, the plasma parameters at each target position include the distribution uniformity of the plasma, and the plasma parameters at each target position are analyzed to determine whether the parameters of the plasma for wafer processing meet the processing requirements, including:

[0025] The density of the plasma at each target position is averaged to obtain the average density of the plasma;

[0026] Based on the average plasma density and the density of the plasma at each target position, determine the density standard deviation of the density of the plasma at each target position, and use the density standard deviation as the distribution uniformity of the plasma;

[0027] Based on the density standard deviation, it is determined whether the distribution uniformity of the plasma meets the processing requirements.

[0028] According to a method for controlling a radio frequency power supply in dual-frequency plasma processing provided by the present invention, the plasma parameters at each target position include the temperature of the plasma body and the pressure of the plasma. The plasma parameters at each target position are analyzed to determine whether the parameters of the plasma for wafer processing meet the processing requirements, including:

[0029] The temperature and pressure of the plasma at each target position are averaged respectively;

[0030] The average value of the plasma temperature is compared with the processing set temperature, and the average value of the plasma pressure is compared with the processing set pressure to determine whether the temperature and pressure of the plasma for wafer processing meet the requirements.

[0031] According to a method for controlling RF power in dual-frequency plasma processing provided by the present invention, the target position includes at least one of a wall position of the processing space, a center position of the processing space, and a processing position of a wafer.

[0032] According to a method for controlling radio frequency power supply in dual-frequency plasma processing provided by the present invention, the target process is determined by dividing the wafer into different etching parameters under plasma.

[0033] The present invention also provides a radio frequency power supply control device for dual-frequency plasma processing, comprising:

[0034] A first acquisition module is used to collect the real-time power of the high-frequency radio frequency generator when the high-frequency radio frequency generator is discharged according to the first preset power under the target process;

[0035] A second acquisition module is used to collect the real-time power of the low-frequency RF generator when the low-frequency RF generator is discharged according to the second preset power under the target process;

[0036] The third acquisition module is used to collect the plasma parameters at each target position in the wafer processing space, and analyze the plasma parameters at each target position to determine whether the parameters of the plasma processed by the wafer meet the processing requirements;

[0037] A first processing module, configured to determine whether the real-time power of the high-frequency RF generator deviates from the first preset power, and determine whether the real-time power of the low-frequency RF generator deviates from the second preset power when the parameters of the plasma for processing the wafer do not meet the processing requirements;

[0038] The second processing module is used to control the high-frequency RF generator to discharge according to a third preset power when the real-time power of the high-frequency RF generator deviates from the first preset power, and / or control the high-frequency RF generator to discharge according to a fourth preset power when the real-time power of the low-frequency RF generator deviates from the second preset power.

[0039] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method for controlling a radio frequency power supply in dual-frequency plasma processing as described above is implemented.

[0040] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method for controlling a radio frequency power supply in a dual-frequency plasma processing as described in any one of the above is implemented.

[0041] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the method for controlling a radio frequency power supply in a dual-frequency plasma processing as described above is implemented.

[0042] The present invention provides a RF power supply control in dual-frequency plasma processing. By collecting the real-time power of a high-frequency RF generator and a low-frequency RF generator, the actual power deviation in each target process can be obtained. When the plasma parameters do not meet the processing requirements, the power of the corresponding RF power supply can be adjusted so that the RF power supply can compensate for power fluctuations in time, thereby enabling the plasma parameters to continue to meet the wafer processing requirements and maintain stability, which is beneficial to the control and stability of the processing process and avoids processing defects or quality fluctuations caused by unstable plasma parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 This is one of the flow diagrams of a method for controlling a radio frequency power supply in dual-frequency plasma processing provided by the present invention;

[0045] Figure 2 This is the second flow chart of a method for controlling a radio frequency power supply in dual-frequency plasma processing provided by the present invention;

[0046] Figure 3 It is a structural schematic diagram of a radio frequency power supply control device in dual-frequency plasma processing provided by the present invention;

[0047] Figure 4 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] Those skilled in the art will appreciate that, unless expressly stated, the singular forms "one", "said", and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the embodiments of the present application means that the corresponding features may be implemented as the presented features, information, data, steps, operations, elements, and / or components, but does not exclude implementation as other features, information, data, steps, operations, elements, components, and / or combinations thereof supported by the technical field. In the embodiments of the present application, the term "and / or" used indicates at least one of the items defined by the term, for example, "A and / or B" may be implemented as "A", or as "B", or as "A and B".

[0050] Combine the following Figure 1-Figure 4 The present invention describes a method for controlling radio frequency power supply in dual-frequency plasma processing.

[0051] A radio frequency power supply is a device used to generate radio frequency (RF) signals. RF signals are usually used in wireless communications, radio frequency circuits in electronic devices, medical equipment, scientific research, and industrial production.

[0052] In the field of semiconductor processing, RF power is usually used to generate high-frequency RF signals to excite plasma, control ion energy, and implement plasma etching and other processes. The characteristics of RF power include high frequency stability, adjustable power, and controllable output waveform, which make it have important application value in semiconductor manufacturing and other high-tech fields.

[0053] It is understood that the RF power source used for semiconductor processing may include a high-frequency RF generator and a low-frequency RF generator. The high-frequency RF generator is used to ionize the reaction gas introduced into the reaction chamber to generate plasma, and the low-frequency RF generator is used to control the energy of the ions incident on the wafer surface.

[0054] High-frequency RF generators are mainly used to generate high-frequency RF signals, which are used to ionize the reaction gas introduced into the reaction chamber to generate plasma. Plasma is a highly ionized gas state with high conductivity and reactivity, and can be used in plasma etching and other processes in the fields of semiconductor processing.

[0055] The low-frequency RF generator is mainly used to control the energy of the ions incident on the wafer surface. In the plasma etching process, ion energy is an important parameter, which affects key factors such as etching rate, etching quality and etching selectivity. By adjusting the parameters of the low-frequency RF generator, such as power, the energy of the ions can be controlled, thereby achieving precise control of the etching process.

[0056] like Figure 1 As shown, a method for controlling RF power supply in dual-frequency plasma processing according to an embodiment of the present invention mainly comprises the steps of

[0057] Step 110 , when the high-frequency RF generator is discharged according to the first preset power in the target process, the real-time power of the high-frequency RF generator is collected.

[0058] It should be noted that the target process is determined according to different etching parameters of the wafer under plasma.

[0059] The target process is determined according to the different etching parameters of the wafer under plasma. It can be understood that the etching process is divided into different stages or processes according to the actual processing needs and requirements, and specific etching parameters are set for each process. The specific method of this division and setting can be adjusted and optimized according to different processing requirements and material properties to achieve precise control and optimization of the wafer etching process.

[0060] Specifically, the division of target processes usually considers etching parameters such as etching depth, rate, etching selectivity, surface quality and accuracy.

[0061] It is understandable that different processes may require different etching depths or different etching rates, so the corresponding etching parameters need to be set according to the target requirements. For different materials or structures, different etching selectivities need to be achieved, that is, while ensuring the etching target, the impact on other parts is minimized. For application scenarios with high process requirements such as wafer etching, the surface quality and accuracy after etching also need to be guaranteed.

[0062] In some embodiments, the output port signal of the high-frequency RF generator can be directly measured by connecting an oscilloscope or a spectrum analyzer, and the real-time power can be calculated by observing the waveform and spectrum characteristics of the output signal.

[0063] In some embodiments, a professional power meter device may also be used for power measurement. A power meter is a device specifically used to measure RF power and performs real-time power measurement by connecting to a specific port of a high-frequency RF generator.

[0064] Of course, you can also use signal analysis software or data acquisition software to connect an adapter or interface device to monitor and record the discharge spectrum and other signals of the high-frequency RF generator in real time, and perform power analysis and processing to analyze and obtain real-time power.

[0065] Step 120 : While the low-frequency RF generator is being discharged at a second preset power under a target process, the real-time power of the low-frequency RF generator is collected.

[0066] It can be understood that after the high-frequency RF generator starts discharging for a set interval time, the low-frequency RF generator will discharge according to the second preset power under the target process, so that the plasma under the action of the high-frequency RF generator can process the wafer at the processing position.

[0067] Step 130 , collecting plasma parameters at each target position in the wafer processing space, and analyzing the plasma parameters at each target position to determine whether the parameters of the plasma for wafer processing meet the processing requirements.

[0068] The target position includes at least one of a wall position of the processing space, a center position of the processing space, and a processing position of the wafer.

[0069] The purpose of considering each target position is to fully understand the distribution and characteristics of the plasma during the processing, especially the energy distribution and distribution uniformity of the plasma.

[0070] Plasma may have different density, energy distribution and characteristics at different locations in the processing space. For example, the location near the wall may be affected by the electric field or wall effect, resulting in different plasma characteristics from the center. The processing location of the wafer can better reflect the characteristics of the current processing process. Therefore, considering the plasma characteristics at different locations can provide a more comprehensive understanding of the situation in the processing space during the processing process.

[0071] The characteristics of plasma directly affect the processing results, such as etching rate, surface quality, etc. By monitoring the plasma parameters at different positions, the influence of different positions on the processing results can be evaluated, thereby optimizing the processing parameters and process flow.

[0072] The plasma parameters at each target position include at least one of plasma density, plasma distribution uniformity, plasma temperature, and plasma pressure.

[0073] The density of plasma refers to the number of plasma particles per unit volume. An increase in density usually increases the energy of the plasma, thereby increasing the etching rate and etching depth. High-density plasma can also improve the selectivity of etching, making fine etching on complex structures more controllable.

[0074] The uniformity of plasma distribution refers to the uniformity of plasma in the processing space. Uniform plasma distribution can ensure the stability and consistency of the entire processing process, and avoid uneven processing or local process abnormalities caused by uneven energy in the same processing step.

[0075] The temperature of the plasma affects the activity and energy distribution of the plasma. Higher plasma temperatures generally increase the etching rate, but may also cause thermal damage or deformation of the wafer surface. Therefore, controlling the appropriate plasma temperature is critical to achieving efficient and stable quality processing.

[0076] The pressure of plasma has a direct impact on the density and energy of plasma. Increasing the pressure of plasma can increase its density and energy, thereby improving the etching rate and selectivity, so it is necessary to control the plasma pressure within an appropriate range.

[0077] Each parameter plays a different role in wafer processing and needs to be reasonably monitored and regulated according to specific processing requirements and material properties to achieve good processing results and product quality.

[0078] In some embodiments, the plasma parameters at each target position include a plasma density, and the plasma parameters at each target position are analyzed to determine whether the parameters of the plasma for wafer processing meet processing requirements, including: when the plasma density at the processing position of the wafer meets the processing requirements, averaging the plasma density at each target position to obtain an average plasma density; and determining whether the average plasma density meets the plasma density requirement.

[0079] First, it is necessary to use appropriate sensors or monitoring equipment to collect plasma parameter data, including density, at various target locations.

[0080] For example, a selected spectrometer or spectral analysis system can be used to perform spectral measurements on the plasma to obtain relevant spectral data. The collected spectral data is imported into the spectral analysis software for processing and analysis. Based on the characteristic peaks or lines in the spectrum, the type and concentration of elements in the plasma can be inferred. Some features in the spectral data, such as line width, light intensity and other parameters, are related to the plasma density. The density of the plasma can be calculated by comparing with known standards or theoretical models, and then using the features in the spectral data in the spectral information.

[0081] The collected plasma density data of each target position can be analyzed by using statistical analysis methods or data processing software to calculate the plasma density at each position.

[0082] On this basis, according to the plasma density requirements of wafer processing, it is determined whether the plasma density at the processing position of the wafer meets the processing requirements.

[0083] If the density of the plasma at the processing position of the wafer has met the processing requirements, the average density of the plasma at each target position can be calculated to obtain the average density of the plasma.

[0084] The calculated average plasma density is compared with the plasma density requirement in the processing requirements to determine whether the requirements are met. If the requirements are not met, it means that during the continuous processing, the plasma density at the processing position of the subsequent wafer may not meet the requirements, and the plasma density in the subsequent processing needs to be increased.

[0085] In some embodiments, the plasma parameters at each target position include the distribution uniformity of the plasma. The plasma parameters at each target position are analyzed to determine whether the parameters of the plasma for wafer processing meet the processing requirements, including the following process.

[0086] The density of plasma at each target position can be averaged to obtain the average density of plasma. Based on the average density of plasma and the density of plasma at each target position, the density standard deviation of the density of plasma at each target position is determined, and the density standard deviation is used as the distribution uniformity of plasma; finally, based on the density standard deviation, it is determined whether the distribution uniformity of plasma meets the processing requirements.

[0087] It can be understood that by processing the density of the plasma at each target position and calculating the average value of these density values, the average density of the plasma can be obtained.

[0088] After obtaining the average density of the plasma, the standard deviation of the density is calculated based on the plasma density data at each target position. The standard deviation of the density reflects the distribution of the plasma density. The smaller the standard deviation, the more uniform the plasma density distribution, and the larger the standard deviation, the more uneven the distribution.

[0089] The calculated density standard deviation is compared with the requirements for plasma distribution uniformity in the processing requirements. If the density standard deviation is less than or equal to the allowable range of distribution uniformity specified in the processing requirements, it is considered that the plasma distribution uniformity meets the processing requirements; otherwise, it is necessary to further adjust the process or parameters to improve the plasma distribution uniformity.

[0090] It is understandable that although the overall average density of the plasma gas meets the requirements, the uniformity of the plasma distribution must still be considered. When the plasma distribution uniformity is too poor, even under the action of a low-frequency RF generator, in some cases, the processing position of the wafer may still not be able to continuously obtain stable plasma for processing.

[0091] In some embodiments, the plasma parameters at each target position include the temperature of the plasma and the pressure of the plasma. The plasma parameters at each target position are analyzed to determine whether the parameters of the plasma for wafer processing meet the processing requirements, including: taking the average value of the temperature and pressure of the plasma at each target position; comparing the average value of the plasma temperature with the processing set temperature, and comparing the average value of the plasma pressure with the processing set pressure, to determine whether the temperature and pressure of the plasma for wafer processing meet the requirements.

[0092] It is understandable that the plasma temperature and pressure at each target position may be measured or data may be collected, and the average values ​​of these parameters may be calculated to obtain the average temperature and average pressure of the plasma.

[0093] The average value of the calculated plasma temperature is compared with the temperature set for processing to determine whether it meets the processing requirements. Similarly, the average value of the plasma pressure is compared with the pressure set for processing to determine whether it meets the processing requirements.

[0094] According to the comparison results, if the average temperature and pressure of the plasma are within the range of processing requirements, it can be considered that the temperature and pressure of the plasma meet the processing requirements; otherwise, the process or parameters need to be adjusted to meet the requirements.

[0095] It is understandable that temperature and pressure are important parameters that affect the effect and quality of plasma processing. By analyzing and comparing them, it is possible to effectively evaluate whether the plasma parameters meet the processing requirements.

[0096] Step 140 , when the parameters of the plasma for wafer processing do not meet the processing requirements, determine whether the real-time power of the high-frequency RF generator deviates from the first preset power, and determine whether the real-time power of the low-frequency RF generator deviates from the second preset power.

[0097] It should be noted that when adjusting the plasma parameters for wafer processing, the power of the RF generator is an important influencing factor.

[0098] Higher RF power usually leads to higher plasma density, because higher power can provide more energy for ionizing gas, thus generating more plasma. Therefore, when the RF power is insufficient, the density and energy of plasma are not enough.

[0099] An increase in RF power can cause the temperature of the plasma to increase, because higher power means more energy is input into the plasma, increasing its internal energy and thus the temperature. An increase in RF power can increase the pressure of the plasma, because higher power generally causes more gas ionization and activity, which increases the gas pressure.

[0100] There are often complex interactions between these parameters. For example, increasing power may lead to an increase in density and temperature, which in turn affects pressure. If the power of the RF generator fluctuates, then plasma parameters such as density, temperature and pressure will also fluctuate or deviate from the expected values, which will also affect the uniformity of the plasma distribution.

[0101] In addition to high-frequency RF generators, when the power of low-frequency RF generators fluctuates, the distribution uniformity of plasma is also greater. The plasma may form plasma clusters. The different power sizes of low-frequency RF generators will have significantly different effects on plasma clusters of different sizes, thereby affecting the distribution uniformity of plasma.

[0102] Therefore, when the parameters of the plasma for wafer processing do not meet the processing requirements, it is necessary to return to confirm whether there is a deviation in the actual output power of the RF power supply, that is, to determine whether the real-time power of the high-frequency RF generator deviates from the first preset power, and to determine whether the real-time power of the low-frequency RF generator deviates from the second preset power.

[0103] In the case of power deviation, the output power of the RF power supply can be adjusted in the subsequent process, so that the parameters of the plasma for wafer processing meet the processing requirements.

[0104] Step 150: When the real-time power of the high-frequency RF generator deviates from the first preset power, the high-frequency RF generator is controlled to discharge according to a third preset power, and / or, when the real-time power of the low-frequency RF generator deviates from the second preset power, the high-frequency RF generator is controlled to discharge according to a fourth preset power.

[0105] It should be noted that, as a power supply device, the RF generator itself is prone to output power fluctuations. These fluctuations may be caused by factors such as unstable performance of circuit components, temperature changes, and interference in the power supply.

[0106] Especially in the long-term etching process of wafers, the temperature of the internal components of the RF generator will become higher and higher with the use of time, and even electromagnetic interference may be generated, which may lead to performance degradation, fluctuation or deviation of the output power, and then the generated plasma cannot meet the processing requirements, or there will not be enough plasma to process the wafer.

[0107] In some embodiments, if only the real-time power of the high-frequency RF generator deviates, then when the real-time power of the high-frequency RF generator deviates from the first preset power, the high-frequency RF generator is controlled to discharge according to the third preset power.

[0108] In some embodiments, if only the real-time power of the low-frequency RF generator deviates, then when the real-time power of the low-frequency RF generator deviates from the second preset power, the high-frequency RF generator is controlled to discharge according to the fourth preset power.

[0109] In some embodiments, if the real-time powers of the high-frequency RF generator and the low-frequency RF generator both deviate from the first preset power, when the real-time power of the high-frequency RF generator deviates from the first preset power, the high-frequency RF generator is controlled to discharge according to the third preset power, and when the real-time power of the low-frequency RF generator deviates from the second preset power, the high-frequency RF generator is controlled to discharge according to the fourth preset power.

[0110] If the real-time power of the high-frequency RF generator deviates from the first preset power, the parameters of the high-frequency RF generator can be adjusted by the control system so that its output power becomes the third preset power.

[0111] If the real-time power of the low-frequency RF generator deviates from the second preset power, the parameters of the low-frequency RF generator can be adjusted by corresponding control means so that its output power becomes the fourth preset power.

[0112] In some embodiments, the third preset power is obtained based on the first preset power and the fluctuation range of the real-time power of the high-frequency RF generator, and the fourth preset power is obtained based on the second preset power and the fluctuation range of the real-time power of the low-frequency RF generator.

[0113] It can be understood that the instability of the output power of the RF generator can be gained and compensated by setting a preset power based on the power fluctuation range to ensure that the plasma parameters remain stable within a certain range. This can effectively cope with the fluctuation of the output power of the RF generator, which is beneficial to improving the controllability and stability of the processing process, thereby improving the processing quality and efficiency.

[0114] According to a method for controlling RF power supply in dual-frequency plasma processing provided by an embodiment of the present invention, by collecting the real-time power of a high-frequency RF generator and a low-frequency RF generator, the actual power deviation in each target process can be obtained. When the plasma parameters do not meet the processing requirements, the power of the corresponding RF power supply can be adjusted so that the RF power supply can compensate for power fluctuations in time, thereby enabling the plasma parameters to continue to meet the wafer processing requirements and maintain stability, which is beneficial to the control and stability of the processing process and avoids processing defects or quality fluctuations caused by unstable plasma parameters.

[0115] In some embodiments, the third preset power may be determined by the following steps. Figure 2 As shown, the third preset power can be determined through steps 210 , 220 , and 230 .

[0116] Step 210: Obtain a first power curve of the real-time power of the high-frequency RF generator varying with time according to the real-time power of the high-frequency RF generator.

[0117] Step 220: Based on the first power curve, identify a first ratio of the time corresponding to the power fluctuation range of the high-frequency RF generator to the discharge time of the high-frequency RF generator.

[0118] Step 230: Determine a third preset power based on the first preset power and the first ratio.

[0119] The collected power data can be processed to generate a curve of power variation over time. This process can be completed through data processing software or programming languages ​​(such as Python, MATLAB, etc.).

[0120] Specifically, the power data can be sorted by time and possibly smoothed to remove noise or sudden changes. Then, a graph can be drawn based on time and power values.

[0121] The generated power-over-time curve is analyzed to identify the power change trend and periodic fluctuation. The obtained power fluctuation range can be compared with the discharge time. For example, the ratio of the time length of the power fluctuation range to the total discharge time can be used as the first ratio. This ratio can reflect the proportion of the fluctuation range to the discharge time, thereby evaluating the stability and volatility of the power.

[0122] It should be noted that the power fluctuation range of the high-frequency RF generator is determined based on the power size when the high-frequency RF generator is discharged and the rate of change of the power.

[0123] First, it is necessary to consider the power level of the high-frequency RF generator when it is discharged. That is, the power level output by the equipment under normal operation. Changes in power level will directly affect the generation and stability of plasma. Secondly, it is necessary to consider the rate of power change, that is, the degree of power change per unit time. The rate of power change reflects the instantaneous stability and volatility of the equipment output power, and has a great impact on the equipment processing process.

[0124] Specifically, a reasonable power fluctuation range can be set according to the corresponding first preset power. When the real-time power exceeds this range, it can be considered that the power has deviated. However, if the real-time power changes very fast within this power fluctuation range, the power fluctuation is also very large, which will also affect the effect of the RF power supply discharge.

[0125] In combination with the first preset power and the first ratio, an integral algorithm or a regression formula may be used to calculate a third preset power, and this preset power may be corrected according to the first ratio to achieve power compensation and control.

[0126] For example, the first preset power is set to P1, the real-time power is set to P2, and the third preset power is set to P3.

[0127] According to the real-time power change, a reasonable power fluctuation range is determined, which can be a fixed value or dynamically adjusted according to the actual situation. P3 can be calculated using a linear or nonlinear correction method according to the specific situation. For example, the percentage of P1 can be increased or decreased according to the size of the first ratio R to obtain the corrected P3. The formula can be: P3 = P1 + (P1 f (R)), where f (R) is a function that changes according to the R value, and f (R) can be set according to experimental data.

[0128] In this embodiment, the third preset power can be calculated according to the real-time power fluctuation, so as to achieve compensation and control of power fluctuation. In practical applications, it may be necessary to adjust the threshold and correction method according to the specific situation to achieve better control effect.

[0129] In some embodiments, the fourth preset power is determined in a similar manner as the third preset power.

[0130] That is, first, according to the real-time power of the low-frequency RF generator, a second power curve of the real-time power of the low-frequency RF generator changing with time is obtained, and then based on the second power curve, a second ratio of the time corresponding to the power fluctuation range of the low-frequency RF generator to the discharge time of the low-frequency RF generator is identified; finally, based on the second preset power and the second ratio, a fourth preset power is determined.

[0131] It should be noted that the power fluctuation range of the low-frequency RF generator is determined based on the power size when the low-frequency RF generator is discharged and the rate of change of the power.

[0132] The specific implementation of the fourth preset power can be obtained by referring to the confirmation method of the third preset power mentioned above, which will not be repeated here.

[0133] The following is a description of a RF power supply control device for dual-frequency plasma processing provided by the present invention. The RF power supply control device for dual-frequency plasma processing described below and the RF power supply control method for dual-frequency plasma processing described above can be referenced to each other.

[0134] A radio frequency power supply control device in dual-frequency plasma processing according to an embodiment of the present invention mainly includes a first acquisition module 310 , a second acquisition module 320 , a third acquisition module 330 , a first processing module 340 and a second processing module 350 .

[0135] The first acquisition module 310 is used to collect the real-time power of the high-frequency RF generator when the high-frequency RF generator is discharged according to the first preset power under the target process;

[0136] The second acquisition module 320 is used to collect the real-time power of the low-frequency RF generator when the low-frequency RF generator is discharged according to the second preset power under the target process;

[0137] The third acquisition module 330 is used to collect the plasma parameters at each target position in the wafer processing space, and analyze the plasma parameters at each target position to determine whether the parameters of the plasma processed by the wafer meet the processing requirements;

[0138] The first processing module 340 is used to determine whether the real-time power of the high-frequency RF generator deviates from the first preset power, and determine whether the real-time power of the low-frequency RF generator deviates from the second preset power when the parameters of the plasma for processing the wafer do not meet the processing requirements;

[0139] The second processing module 350 is used to control the high-frequency RF generator to discharge according to a third preset power when the real-time power of the high-frequency RF generator deviates from the first preset power, and / or, when the real-time power of the low-frequency RF generator deviates from the second preset power, control the high-frequency RF generator to discharge according to a fourth preset power.

[0140] According to an RF power supply control device in dual-frequency plasma processing provided by an embodiment of the present invention, by collecting the real-time power of a high-frequency RF generator and a low-frequency RF generator, the actual power deviation in each target process can be obtained. When the plasma parameters do not meet the processing requirements, the power of the corresponding RF power supply can be adjusted so that the RF power supply can compensate for power fluctuations in time, thereby enabling the plasma parameters to continue to meet the wafer processing requirements and maintain stability, which is beneficial to the control and stability of the processing process and avoids processing defects or quality fluctuations caused by unstable plasma parameters.

[0141] Figure 4 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 4 As shown, the electronic device may include: a processor (processor) 410, a communication interface (Communications Interface) 420, a memory (memory) 430 and a communication bus 440, wherein the processor 410, the communication interface 420, and the memory 430 communicate with each other through the communication bus 440. The processor 410 can call the logic instructions in the memory 430 to execute the RF power control method in the dual-frequency plasma processing, which includes: collecting the real-time power of the high-frequency RF generator during the discharge of the high-frequency RF generator according to the first preset power under the target process; collecting the real-time power of the low-frequency RF generator during the discharge of the low-frequency RF generator according to the second preset power under the target process; collecting the plasma parameters at each target position in the wafer processing space, and analyzing the plasma parameters at each target position to determine whether the parameters of the plasma processed by the wafer meet the processing requirements; if the parameters of the plasma processed by the wafer do not meet the processing requirements, determining whether the real-time power of the high-frequency RF generator deviates from the first preset power, and determining whether the real-time power of the low-frequency RF generator deviates from the second preset power; if the real-time power of the high-frequency RF generator deviates from the first preset power, controlling the high-frequency RF generator to discharge according to the third preset power, and / or, if the real-time power of the low-frequency RF generator deviates from the second preset power, controlling the high-frequency RF generator to discharge according to the fourth preset power.

[0142] In addition, the logic instructions in the above-mentioned memory 430 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0143] On the other hand, the present invention also provides a computer program product, which includes a computer program, which can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the RF power control method in dual-frequency plasma processing provided by the above methods, the method comprising: collecting the real-time power of the high-frequency RF generator during the discharge of the high-frequency RF generator according to the first preset power under the target process; collecting the real-time power of the low-frequency RF generator during the discharge of the low-frequency RF generator according to the second preset power under the target process; collecting plasma parameters at each target position in the wafer processing space, and analyzing the plasma parameters at each target position to determine whether the parameters of the plasma processed by the wafer meet the processing requirements; if the parameters of the plasma processed by the wafer do not meet the processing requirements, determining whether the real-time power of the high-frequency RF generator deviates from the first preset power, and determining whether the real-time power of the low-frequency RF generator deviates from the second preset power; if the real-time power of the high-frequency RF generator deviates from the first preset power, controlling the high-frequency RF generator to discharge according to the third preset power, and / or, if the real-time power of the low-frequency RF generator deviates from the second preset power, controlling the high-frequency RF generator to discharge according to the fourth preset power.

[0144] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the computer program is executed by a processor to execute the RF power control method in the dual-frequency plasma processing provided by the above methods, the method comprising: collecting the real-time power of the high-frequency RF generator during the discharge of the high-frequency RF generator according to the first preset power under the target process; collecting the real-time power of the low-frequency RF generator during the discharge of the low-frequency RF generator according to the second preset power under the target process; collecting the plasma parameters at each target position in the wafer processing space, and analyzing the plasma parameters at each target position to determine whether the parameters of the plasma processed by the wafer meet the processing requirements; if the parameters of the plasma processed by the wafer do not meet the processing requirements, determining whether the real-time power of the high-frequency RF generator deviates from the first preset power, and determining whether the real-time power of the low-frequency RF generator deviates from the second preset power; if the real-time power of the high-frequency RF generator deviates from the first preset power, controlling the high-frequency RF generator to discharge according to the third preset power, and / or, if the real-time power of the low-frequency RF generator deviates from the second preset power, controlling the high-frequency RF generator to discharge according to the fourth preset power.

[0145] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0146] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling radio frequency power supply in dual-frequency plasma processing, characterized in that: The radio frequency power supply includes a high-frequency radio frequency generator and a low-frequency radio frequency generator, wherein the high-frequency radio frequency generator is used to ionize the reaction gas introduced into the reaction chamber to generate plasma, and the low-frequency radio frequency generator is used to control the energy of ions incident on the surface of the wafer. The method includes: When the high-frequency RF generator is discharged according to the first preset power under the target process, the real-time power of the high-frequency RF generator is collected; During the process of the low-frequency RF generator discharging according to the second preset power under the target process, collecting the real-time power of the low-frequency RF generator; Collecting plasma parameters at each target position in the wafer processing space, and analyzing the plasma parameters at each target position to determine whether the parameters of the plasma for wafer processing meet the processing requirements; In the case where the parameters of the plasma processed for the wafer do not meet the processing requirements, determining whether the real-time power of the high-frequency RF generator deviates from the first preset power, and determining whether the real-time power of the low-frequency RF generator deviates from the second preset power; When the real-time power of the high-frequency RF generator deviates from the first preset power, the high-frequency RF generator is controlled to discharge according to a third preset power, and / or when the real-time power of the low-frequency RF generator deviates from the second preset power, the high-frequency RF generator is controlled to discharge according to a fourth preset power.

2. The method for controlling RF power supply in dual-frequency plasma processing according to claim 1, characterized in that: The third preset power is obtained based on the first preset power and the fluctuation range of the real-time power of the high-frequency RF generator, and the fourth preset power is obtained based on the second preset power and the fluctuation range of the real-time power of the low-frequency RF generator.

3. The method for controlling RF power supply in dual-frequency plasma processing according to claim 2, characterized in that: The third preset power is determined by: According to the real-time power of the high-frequency radio frequency generator, a first power curve of the real-time power of the high-frequency radio frequency generator varying with time is obtained; Based on the first power curve, a first ratio of the time corresponding to the power fluctuation range of the high-frequency RF generator to the discharge time of the high-frequency RF generator is identified; the power fluctuation range of the high-frequency RF generator is determined based on the power size and the power change rate when the high-frequency RF generator is discharged; The third preset power is determined based on the first preset power and the first ratio.

4. The method for controlling RF power supply in dual-frequency plasma processing according to claim 2, characterized in that: The fourth preset power is determined by: According to the real-time power of the low-frequency radio frequency generator, a second power curve of the real-time power of the low-frequency radio frequency generator varying with time is obtained; Based on the second power curve, identifying a second ratio of the time corresponding to the power fluctuation range of the low-frequency RF generator to the discharge time of the low-frequency RF generator; the power fluctuation range of the low-frequency RF generator is determined based on the power size and the power change rate when the low-frequency RF generator is discharged; The fourth preset power is determined based on the second preset power and the second ratio.

5. The method for controlling RF power supply in dual-frequency plasma processing according to claim 1, characterized in that: The plasma parameters at each target position include at least one of plasma density, plasma distribution uniformity, plasma temperature, and plasma pressure.

6. The method for controlling RF power supply in dual-frequency plasma processing according to claim 5, characterized in that: The plasma parameters at each target position include the density of the plasma. The plasma parameters at each target position are analyzed to determine whether the parameters of the plasma for wafer processing meet the processing requirements, including: When the density of the plasma at the processing position of the wafer meets the processing requirements, the density of the plasma at each target position is averaged to obtain the average density of the plasma; Determine whether the average plasma density meets the plasma density requirements.

7. The method for controlling RF power supply in dual-frequency plasma processing according to claim 5, characterized in that: The plasma parameters at each target position include the distribution uniformity of the plasma. The plasma parameters at each target position are analyzed to determine whether the parameters of the plasma for wafer processing meet the processing requirements, including: The density of the plasma at each target position is averaged to obtain the average density of the plasma; Based on the average plasma density and the density of the plasma at each target position, determine the density standard deviation of the density of the plasma at each target position, and use the density standard deviation as the distribution uniformity of the plasma; Based on the density standard deviation, it is determined whether the distribution uniformity of the plasma meets the processing requirements.

8. The method for controlling RF power supply in dual-frequency plasma processing according to claim 5, characterized in that: The plasma parameters at each target position include the temperature of the plasma and the pressure of the plasma. The plasma parameters at each target position are analyzed to determine whether the parameters of the plasma for wafer processing meet the processing requirements, including: The temperature and pressure of the plasma at each target position are averaged respectively; The average value of the plasma temperature is compared with the processing set temperature, and the average value of the plasma pressure is compared with the processing set pressure to determine whether the temperature and pressure of the plasma for wafer processing meet the requirements.

9. The method for controlling RF power supply in dual-frequency plasma processing according to claim 1, characterized in that: The target position includes at least one of a wall position of the processing space, a center position of the processing space, and a processing position of a wafer.

10. The method for controlling radio frequency power supply in dual frequency plasma processing according to claim 1, characterized in that: The target process is determined according to different etching parameters of the wafer under plasma.

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