Radio frequency plasma comprehensive testing device and method for ion process system

Abstract

The invention discloses a radio frequency plasma comprehensive testing device and method for an ion process system, and relates to the technical field of plasma testing, and the device comprises a host and a coupling probe; the coupling probe is placed on a radio frequency transmission line of an ion process system, is used for carrying out coupling sampling on radio frequency energy through a capacitance or inductance coupling mode according to an electromagnetic field coupling principle, obtains current and voltage signals through coupling, and is also used for sensing and obtaining real-time temperature data in the probe; the host comprises a main body shell and a shielding frame arranged in the main body shell, and a data processing and analyzing unit is arranged in the shielding frame and used for performing data processing on the received voltage, current and temperature signals; the radio frequency power supply power, the radio frequency power supply frequency spectrum, the impedance of the matcher and the vacuum reaction cavity and other ion process system parameter values are calculated and generated, and meanwhile clutter capture and radio frequency transmission harmonic wave test results in radio frequency transmission are output, so that the comprehensive test of the ion process system is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of plasma testing, and particularly to a radio frequency plasma comprehensive testing device and method for an ion process system. Background Art

[0002] The statements in this part only provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] Plasma-related processes are currently one of the most important processes in the semiconductor field. Plasma-related applications require the use of an ion process system. The entire ion process system includes a radio frequency power supply that generates the radio frequency energy required for ions, a carrier radio frequency coaxial cable and a radio frequency connector that transmit the radio frequency energy, a radio frequency power supply matcher that adjusts the overall transmission impedance, and a vacuum reaction chamber that provides the necessary environment for plasma generation. The main problems faced in the ion process system lie in the instability of the radio frequency power supply and the overall impedance matching degree of the ion process system. Among them: ① The radio frequency power supply is essentially a high-power device that amplifies a small radio frequency signal into a large signal. Limited by its working principle, clutter and harmonics will inevitably occur. Once clutter and harmonics occur, they will affect the instability of the process, thereby affecting the yield of the chip. As a device that is used intensively for a long time, the radio frequency power supply often needs to face the problem of component aging. Once component aging occurs, the output of the radio frequency power supply will shift, thereby affecting the accuracy of each process. The change in impedance is also one of the important factors affecting the radio frequency power supply. ② In the ion process system, various parameters such as power, voltage, and the phase corresponding to the current need to be highly matched with the preset parameters so that the reliability of the semiconductor manufacturing process cycle can be demonstrated and the stability of the process (i.e., ensuring the yield and efficiency) can be guaranteed. Therefore, whether it is an ion process system during initial debugging or an ion process system that has been put into production and has been running for a long time, the reliability of the ion process system needs to be frequently detected. Only by ensuring consistent power, voltage, and the phase of the current and voltage in the ion process system can the manufacturing process of the chip be basically guaranteed.

[0004] To detect the reliability of the ion process system, various detection methods have been proposed currently, including:

[0005] (1) The through-type power meter test scheme, as the most common test scheme in the industry currently, usually consists of several power sensors, radio frequency components, a power meter, and a high-power dummy load. Its main function is to be able to measure the power value of the radio frequency power supply more accurately and judge the state of the overall line connection based on this power value. However, the test instruments required for this method are extremely expensive, the subsequent maintenance costs are high, and the functions are single. It can only measure the power value, cannot capture clutter and harmonics, and cannot measure impedance.

[0006] (2) Absorption power meter test scheme, as a relatively common test scheme in the industry at present, usually consists of a power attenuator and an absorption power meter. Its main function is to test the output power of the RF power supply. This method is a relatively low-cost test scheme, but it cannot monitor the actual working power state when the RF power supply is connected to the machine tool, nor can it judge the connection state of the overall circuit. Its function is single, and it can only measure the power value. It cannot capture clutter and harmonics, nor can it measure impedance.

[0007] (3) Spectrum analyzer test scheme, as a relatively common test scheme in the industry, usually consists of a high-power coupler and a spectrum analyzer. This scheme can test the spectrum of the RF power supply. By analyzing the spectrum, the clutter and harmonics of the RF power supply can be tested, and the stability of the RF power supply can be tested in the frequency dimension. However, this scheme has a single function and cannot test the power value of the RF power supply.

[0008] (4) VI sensor test scheme, as a relatively rare test scheme in the industry, usually consists of a VI probe and a matching host analysis module. It can analyze the voltage and current information in the transmission line by calculation to obtain the impedance parameter, and can also calculate the power according to the voltage and current information. However, the equipment used in this scheme is expensive, the cost is high, and the power is obtained by calculation, so the accuracy is low, the overall use convenience is poor, and the technical requirements for the users are high.

[0009] Therefore, the existing test schemes for ion process systems all have certain limitations. Most of them can only handle or solve one aspect of the problems and achieve a single test function. If all the above-mentioned equipment is used for comprehensive testing, although it can solve the limitation problem of testing to a certain extent, the cost is too high, and it is necessary to continuously disassemble and assemble to obtain the required multiple values, and the operation is too cumbersome and complex. Summary of the Invention

[0010] To solve the deficiencies of the above-mentioned existing technologies, the present invention provides a radio frequency plasma comprehensive test device and method for an ion process system. According to the electromagnetic field coupling principle, an induction probe is designed to couple and sample the radio frequency energy transmitted in the radio frequency cable, and then the coupled signals such as current, voltage, and temperature are analyzed and processed. At the same time, the power detection of the RF power supply, the spectrum analysis of the RF power supply, the impedance analysis of the matcher and the vacuum reaction chamber, the clutter capture in the RF transmission, the harmonic test in the RF transmission, the arc capture in the plasma vacuum reaction chamber, the capture of possible RF leakage in the transmission line, and the test of various parameters of the ion process system (such as standing wave ratio, insertion loss, return loss, impedance, etc.) are completed to achieve the synchronous completion of multiple functions and avoid the problems of high cost and limitations existing in the existing test devices.

[0011] In a first aspect, the present invention provides a comprehensive radio frequency plasma testing device for an ion process system.

[0012] A comprehensive radio frequency plasma testing device for an ion process system includes a mainframe and a coupling probe;

[0013] The coupling probe is placed on the radio frequency transmission line of the ion process system and is used to couple and sample radio frequency energy by means of capacitive or inductive coupling according to the electromagnetic field coupling principle, obtain current and voltage signals through coupling, and is used to inductively obtain real-time temperature data inside the probe;

[0014] The mainframe includes a main body housing and a shielding frame arranged inside the main body housing. A data processing and analysis unit is provided inside the shielding frame. The data processing and analysis unit is used to process the received voltage, current, and temperature signals, calculate and generate radio frequency power supply power, radio frequency power supply spectrum, impedance of the matcher and the vacuum reaction chamber, and other ion process system parameter values, and at the same time output the results of clutter capture and radio frequency transmission harmonic testing during radio frequency transmission.

[0015] In a further technical solution, a central induction conductor, a temperature acquisition unit, a current acquisition unit, a voltage acquisition unit, and a signal transmission unit are integrated in the coupling probe; among them:

[0016] The central induction conductor is used to couple and sample radio frequency energy by means of capacitive or inductive coupling according to the electromagnetic field coupling principle;

[0017] Both the current acquisition unit and the voltage acquisition unit are electrically connected to the central induction conductor and are used to obtain original current and voltage signals according to the coupling sampling results of the central induction conductor;

[0018] The temperature acquisition unit is a temperature sensor built into the coupling probe and is used to collect real-time temperature data inside the probe;

[0019] The signal transmission unit is electrically connected to the mainframe through voltage, current signal transmission lines and temperature signal transmission lines and is used to transmit the collected voltage, current, and temperature signals to the data processing and analysis unit of the mainframe.

[0020] In a further technical solution, a power supply unit and a main board control unit are also provided inside the shielding frame. A display panel and an operation panel are embedded on the main body housing, and the power supply unit, the data processing and analysis unit, the display panel, and the operation panel are all electrically connected to the main board control unit, where:

[0021] The power supply unit is used to supply power to the entire device;

[0022] The operation panel is provided with a variety of buttons for generating control signals according to manual operations and transmitting the control signals to the main board control unit;

[0023] The display panel uses an LED, LCD or OLED touch screen for displaying a manipulable interface and the content sent by the main board control unit;

[0024] The main board control unit is used for integrating and driving the operation of other units.

[0025] In a further technical solution, an expansion unit is further provided in the device. The expansion unit includes an expansion data acquisition unit arranged inside the host and an expansion sensor unit connected to the expansion data acquisition unit. The expansion sensor unit adopts any one or more sensors of a VIZ probe, a bi-directional coupling probe, and an antenna receiving module.

[0026] In a further technical solution, an antenna receiving module is arranged in the expansion sensor unit. The antenna receiving module is used for collecting signals and recording the radio frequency signal intensities received at different positions and time points;

[0027] The expansion data acquisition unit is used for receiving the collected signals and transmitting the received signals to the data processing and analysis unit;

[0028] The data processing and analysis unit is used for analyzing the spectrum of the signals and identifying possible radio frequency leakage in the transmission line.

[0029] In a second aspect, the present invention provides a radio frequency plasma comprehensive testing method for an ion process system.

[0030] A radio frequency plasma comprehensive testing method for an ion process system is realized based on a radio frequency plasma comprehensive testing device proposed in the first aspect. The method includes:

[0031] Placing the coupling probe of the radio frequency plasma comprehensive testing device on the radio frequency transmission line of the ion process system and starting the radio frequency plasma comprehensive testing device;

[0032] Using the coupling probe, according to the electromagnetic field coupling principle, coupling and sampling the radio frequency energy through capacitive or inductive coupling methods, obtaining current and voltage signals through coupling, and simultaneously inductively obtaining the real-time temperature data inside the probe, and transmitting the obtained current, voltage signals and temperature data to the host;

[0033] Based on the data processing and analysis unit inside the host, the received voltage, current, and temperature signals are processed, and the radio frequency power supply power, radio frequency power supply spectrum, impedance of the matcher and the vacuum reaction chamber, and other ion process system parameter values are calculated and generated. At the same time, the clutter capture and radio frequency transmission harmonic test results during radio frequency transmission are output.

[0034] A further technical solution further includes:

[0035] Using the expansion unit in the radio frequency plasma comprehensive test device, an antenna receiving module is added to the expansion sensor unit of the expansion unit;

[0036] Using the antenna receiving module to collect signals and record the radio frequency signal intensities received at different positions and time points;

[0037] According to the collected signals received, analyze the signal spectrum to identify possible radio frequency leakage in the transmission line.

[0038] The above one or more technical solutions have the following beneficial effects:

[0039] 1. The present invention provides a radio frequency plasma comprehensive test device and method for an ion process system. According to the electromagnetic field coupling principle, an induction probe is designed to couple and sample the radio frequency energy transmitted in the radio frequency cable, and then the coupled signals such as current, voltage, and temperature are analyzed and processed. At the same time, the power detection of the radio frequency power supply, the spectrum analysis of the radio frequency power supply, the impedance analysis of the matcher and the vacuum reaction chamber, the clutter capture in the radio frequency transmission, the harmonic test in the radio frequency transmission, the arc capture in the plasma vacuum reaction chamber, the possible radio frequency leakage capture in the transmission line, and the testing of various parameters of the ion process system (such as standing wave ratio, insertion loss, return loss, impedance, etc.) are completed, realizing the synchronous completion of multiple functions and avoiding the problems of high cost and limitations of existing test devices.

[0040] 2. The comprehensive test device proposed by the present invention, based on fixed or customized probes, is applied to an ion process system composed of a semiconductor radio frequency power supply, an energy transmission system, a radio frequency power supply matcher, and a plasma vacuum reaction chamber, and can realize the on-line measurement of the forward and reverse power, voltage value, current value, phase value, and impedance of the radio frequency power supply signal. At the same time, it supports the signal capture of up to five fundamental frequencies and up to the fourth harmonic at most, the arc detection in the vacuum reaction chamber, and the analysis of the radio frequency waveform in the time domain during the process. In addition, by adding an expansion unit and expansion sensors, a certain degree of expansion can be carried out on the basis of the above basic functions, such as the matching network efficiency test, the radio frequency power supply fault analysis, the detection of whether there is radio frequency leakage in the test environment, etc., and the application is more comprehensive and extensive.

[0041] Advantages of additional aspects of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0043] Figure 1 It is a schematic structural diagram of the radio frequency plasma comprehensive test device according to an embodiment of the present invention;

[0044] Figure 2 It is a schematic structural diagram of the coupling probe in the device according to an embodiment of the present invention;

[0045] Figure 3 It is a schematic diagram of the test using the coupling probe according to an embodiment of the present invention;

[0046] Figure 4 It is a schematic diagram of the test environment during temperature correction according to an embodiment of the present invention;

[0047] Figure 5 It is a schematic structural diagram of the mainframe in the device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] It should be noted that the following detailed description is exemplary only and is for the purpose of describing specific embodiments, aiming to provide further explanation of the present invention and not intended to limit the exemplary embodiments according to the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. In addition, it should also be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0049] Embodiment 1

[0050] This embodiment provides a radio frequency plasma comprehensive test device for an ion process system, as Figure 1 shown, the device mainly includes a mainframe part and a coupling probe part (also referred to as a sensor part).

[0051] As Figure 3As shown, the ion process system for generating plasma by a radio frequency power supply includes a radio frequency power supply that generates the radio frequency energy required for generating ions, a radio frequency cable that transmits the radio frequency energy, a radio frequency power supply matcher that adjusts the overall transmission impedance, and a vacuum reaction chamber that provides the necessary environment for plasma generation. The radio frequency power supply generates radio frequency energy and enters the cavity part through the cable. The gas is dissociated into plasma by the upper and lower electrodes inside the cavity. Among them, a coupling probe (referred to as the probe for short) is placed on the radio frequency transmission line of the ion process system. It is used to couple and sample the radio frequency energy by means of capacitive or inductive coupling according to the electromagnetic field coupling principle, obtain current and voltage signals through coupling, and is also used to inductively obtain the real-time temperature data inside the probe.

[0052] Regarding the coupling probe proposed in this embodiment, as Figure 2 shown, a central induction conductor, a temperature acquisition unit, a current acquisition unit, a voltage acquisition unit, and a signal transmission unit are integrated in the probe. Among them, the central induction conductor is made of good conductor materials such as copper, aluminum, silver, and gold. According to the electromagnetic field coupling principle, capacitive coupling or inductive coupling and other methods are selected to couple and sample the radio frequency energy. The current acquisition unit and the voltage acquisition unit are both electrically connected to the central induction conductor, and they respectively obtain the original current and voltage signals through the coupling method, that is, these two units are used to obtain the original current and voltage signals according to the coupling sampling result of the central induction conductor.

[0053] Among them, the above-mentioned electromagnetic field coupling principle means that according to Maxwell's equations, the magnetic field and the electric field will transform into each other. When the current or voltage in a circuit or component changes, a changing electromagnetic field will be generated in the surrounding space. This changing electromagnetic field will interact with other nearby circuits or components, so that current or voltage can be induced in these circuits or components, realizing the coupling transmission of energy or signals. In this embodiment, according to the above-mentioned electromagnetic field coupling principle, capacitive or inductive coupling methods are adopted to obtain current and voltage signals through coupling.

[0054] As an implementation method, capacitive coupling can transmit the changing electromagnetic field between two opposite conductors in a non-contact manner and at the same time play the role of isolating direct current. The materials it uses (such as ceramic capacitors, thin film capacitors, mica capacitors, etc.) have the characteristics of low equivalent resistance and low dielectric loss. Therefore, in this embodiment, the capacitive coupling method is adopted, and based on the capacitance characteristics and the advantages of PCB, a PCB-type capacitor is designed and manufactured, which has the characteristics of small volume, easy integration, meeting environmental protection standards, controllable and stable capacitance, higher breakdown voltage and temperature stability, etc. Preferably, the dielectric material in capacitive coupling can be adaptively selected according to the specific application environment.

[0055] As another implementation, inductive coupling is based on Faraday's law of electromagnetic induction, that is, a changing magnetic field forms an induced electromotive force in a conductor, thereby realizing the conversion of magnetic field - current, and then realizing coupling. Inductive coupling can be achieved by using transformers, magnetic ring coils, etc. In this embodiment, a PCB coil is used to equivalent the inductor. Compared with the problem of large volume of traditional coil coupling, the inductive coupling method adopted in this embodiment has the characteristics of strong integratability, customizability, low loss, low distortion, and low EMI, which can ensure that the probe size is smaller and is more conducive to integration into the probe interior.

[0056] Furthermore, considering that the working environment of the probe is usually high power and its ambient temperature is high, for the probe, temperature changes will cause changes in the response of internal circuit components. Therefore, it is also necessary to control the temperature drift of the entire instrument or device, otherwise it will affect the accuracy of the finally coupled and induced acquired signal. For this reason, a temperature acquisition unit, that is, an internal temperature sensor, is also built into the coupling probe part of this embodiment. The internal temperature data of the probe is collected through this temperature sensor for temperature calibration to adjust the data signal deviation caused by temperature drift, thereby increasing the accuracy.

[0057] After obtaining the current, voltage, and temperature data above, all data are aggregated and transmitted to the signal transmission unit in the coupling probe of this embodiment. As Figure 1 shown, the signal transmission unit is electrically connected to the host part of the comprehensive test device through voltage, current signal transmission lines and temperature signal transmission lines for data transmission. The signal transmission unit transmits the three types of signals collected to the data processing and analysis unit of the main body part.

[0058] As Figure 5 shown, the host part in the comprehensive test device (which can also be called the comprehensive test platform) proposed in this embodiment includes a main body shell and a shielding frame. Among them, the shielding frame is arranged inside the main body shell. The main body shell is made of plastic material to make the device lighter, while the shielding frame is made by sheet metal process, and its material can be made of materials with good structural stability and electrical conductivity such as stainless steel, aluminum alloy, copper, etc. This shielding frame serves as the support for the internal PCB and can shield external electromagnetic interference to ensure the accuracy of internal data processing and analysis.

[0059] Inside the above-mentioned shielding frame, there are also a power supply unit, a data processing and analysis unit, and a main board control unit. Moreover, a display panel and an operation panel are embedded on the main body shell to facilitate the use of the device. Among them, the power supply unit, the data processing and analysis unit, the display panel, and the operation panel are all electrically connected to the main board control unit. The power supply unit is used to supply power to the entire device, that is, to supply power to all units or modules that need power supply such as the display panel; on the operation panel, there are buttons for quick jump of the main functions of the software, digital key input, control, etc., which are used to generate control signals according to human operations and transmit the control signals to the main board control unit; the display panel uses a touch screen such as LED, LCD or OLED, which can be used to display a manipulable interface and display the content sent by the main board control unit, etc.; the main board control unit is equipped with an operating system and a self-developed supporting software for the comprehensive tester, and at the same time undertakes some calculation and analysis functions, which are used to integrate and drive other unit parts, and can realize function expansion based on the data processing and analysis unit, such as spectrum analysis function, Smith chart function, etc.; the data processing and analysis unit is used to process the received voltage, current and temperature signals, calculate and generate parameters such as radio frequency power supply power, radio frequency power supply spectrum, impedance of the matcher and the vacuum reaction chamber, and other ion process system parameter values, and at the same time output the results of clutter capture and radio frequency transmission harmonic test in radio frequency transmission.

[0060] Specifically, in the above-mentioned data processing and analysis unit, according to the three signal data of voltage, current and temperature obtained, data processing is carried out. Among them, the voltage signal is subjected to detection processing to convert the AC signal into a DC signal, and then input into the high-speed analog-to-digital converter ADC for calculating parameter values such as radio frequency power supply power; the current signal is subjected to digital quadrature mixing processing to calculate parameter values such as the impedance of the matcher and the vacuum reaction chamber; the temperature signal is obtained by the temperature sensor built in the coupling probe, and this signal is a DC signal, and the temperature signal is directly input into the high-speed analog-to-digital converter ADC for data calibration work based on temperature. The specific process of the above data processing and analysis includes:

[0061] (1) First, calculate and adjust the amplitude and phase of the coupled voltage and current signals.

[0062] Specifically, considering that the voltage and current signals obtained by electromagnetic field coupling will change in amplitude and phase compared with the original signals. For example, the voltage signal will be affected by the original signal frequency, capacitance value, and PCB board material, and the current signal is related to factors such as the PCB coil inductance value, Q value (quality factor), and PCB board material. Therefore, in this embodiment, first, the coupled voltage and current signals are calculated and adjusted to obtain data closer to the original signals and ensure the accuracy of subsequent test results.

[0063] (1.1) Signal amplitude adjustment.

[0064] First, for the voltage and current signals obtained through electromagnetic field coupling, first use a high-speed analog-to-digital converter (ADC) to collect the signals, and then combine the signal buffer unit FPGA and the data analysis unit DSP to analyze the initial amplitude of the signals. Specifically, let the collected signal be where A 0 is the initial amplitude.

[0065] Secondly, determine the target amplitude: that is, use a precision voltage sensor to determine the target amplitude A 1 .

[0066] After that, select the adjustment method: that is, use a programmable amplifier or attenuator to adjust the amplitude. If a programmable amplifier is used, the gain G of the amplifier needs to be determined; if an attenuator is used, the attenuation coefficient k needs to be determined. Among them, the signal amplitude is calculated as:

[0067] ① For the case of using an amplifier: If an amplifier is used to increase the signal amplitude, the calculation formula for the gain G is: gain Taking the initial amplitude A 0 = 1V and the target amplitude A 1 = 5V as an example, then G = 5.

[0068] ② For the case of using an attenuator: If an attenuator is used to decrease the signal amplitude, the calculation formula for the attenuation coefficient k is: and 0 < k < 1. Taking the initial amplitude A 0 = 10V and the target amplitude A 1 = 2V as an example, then the attenuation coefficient k = 0.2.

[0069] Then, implement the adjustment: that is, input the collected signal into the amplifier or attenuator to obtain the adjusted signal

[0070] Finally, repeat the above steps, calibrate the voltage values in the full voltage range at a certain interval and store the calibration data in the encrypted Flash.

[0071] Furthermore, the amplitude of the current is determined by the calibrated voltage and impedance.

[0072] (1.2) Signal phase adjustment.

[0073] First, measure the phase: that is, use a phase measurement instrument (such as an oscilloscope or a spectrum analyzer, etc.) to measure the original phase of the collected signal and use the DSP data analysis unit to calculate the phase of the coupled signal

[0074] Secondly, adjust the phase: That is, according to the original phase obtained by measurement and the phase of the coupled signal, the signal is phase-adjusted at the software level through a digital signal processing algorithm. In this embodiment, an analog phase shifter (with a phase shift of ) is used to perform a phase rotation operation on the discrete signal to achieve phase adjustment. Taking the discrete signal as an example, where T is the sampling period, if the phase is to be adjusted to , it can be obtained by calculating . After expanding it using the sum-of-angles formula of trigonometric functions sin(a + b) = sin a cos b + cos a sin b, it is then calculated and processed according to the characteristics of the discrete signal.

[0075] (2) Secondly, according to the temperature data obtained in real time, perform temperature correction on the adjusted voltage and current signals.

[0076] In this embodiment, a temperature sensor is built inside the coupling probe, which can capture the temperature inside the probe in real time and transmit the temperature back to the upper computer integrated tester (i.e., the comprehensive test device proposed in this embodiment) through a separate signal line. During calibration, a test environment as shown in Figure 4 is built for temperature calibration. Specifically, set the output power of the standard source, adjust the temperature of the temperature control box, and collect the data offset of the coupled signal data under temperature offset conditions; based on the collected voltage and current signal data at different temperatures, use data analysis software (such as Matlab, etc.) for data fitting to obtain the temperature offset curve and its curve formula, so as to form a temperature calibration algorithm.

[0077] In the specific implementation process, according to the pre-acquired temperature offset curve and combined with the real-time acquired temperature data, perform temperature correction on the adjusted voltage and current signals to obtain data that is closer to the original signal and more accurate, ensuring the accuracy of subsequent test results.

[0078] (3) Finally, according to the corrected voltage and current signals, simultaneously calculate the power of the RF power supply, the spectrum of the RF power supply, the impedance of the matcher and the vacuum reaction chamber, and other ion process system parameter values such as clutter capture in RF transmission, harmonic testing in RF transmission, arc capture in the plasma vacuum reaction chamber, and standing wave ratio, insertion loss, return loss, impedance parameters, etc. in the ion process system, so as to achieve the synchronous completion of multiple functions and avoid the problems of high cost and limitations existing in existing test devices.

[0079] Specifically, considering that existing power test methods usually measure power through attenuation and spectrum analyzer amplitude analysis, thermal resistance method, spectral analysis method, etc., but they cannot simultaneously consider multiple parameters such as power, voltage, current, impedance, and phase. Therefore, in this embodiment, a special coupling method is adopted to synchronously couple voltage and current signals, and other parameter data of the system are calibrated from the voltage and current themselves, including:

[0080] (3.1) Power detection of the RF power supply. By analyzing the effective values of the forward and reverse coupling signals and using the fixed coupling degree of the probe to calculate the forward and reverse power, the power detection of the RF power supply is realized.

[0081] Specifically, the detected power is: P = UI * cosθ;

[0082] Where U and I are the effective values of voltage and current respectively. The voltage and current signals change according to the sine law, and their instantaneous value expressions are Where Um and Im are the maximum values of voltage and current respectively, w is the angular frequency, and is the initial phase, then is the phase difference between voltage and current; cosθ is the power factor.

[0083] (3.2) Spectrum of the RF power supply. According to the coupled voltage and current signals for spectrum analysis, that is, the voltage and current digital signals output by the high-speed ADC are filtered by a digital FIR (Finite Impulse Response) filter or an IIR (Infinite-duration Impulse Responses) filter, and then subjected to a fast Fourier transform FFT or a discrete Fourier transform DFT to obtain the spectrum of the corresponding signal. The frequency points are displayed on the display panel in the "time-frequency" relationship through a high sampling rate, that is, the frequency points and their change trends within a certain period of time are displayed.

[0084] (3.3) Impedance analysis of the matcher and the vacuum reaction chamber. According to the collected voltage and current values, the low frequency is extracted through digital quadrature mixing, and then the sampling rate is reduced through decimation. The shaping function of the spectrum is output through low-pass filtering, and the impedance value of the overall matcher and the vacuum reaction chamber is calculated accordingly.

[0085] (3.4) Clutter capture in RF transmission. Through the spectrum analysis in (3.2) above, clutter can be screened out.

[0086] (3.5) RF transmission harmonic test. Similarly, harmonics are usually integer multiples of the fundamental frequency, and harmonics can be screened out through the spectrum analysis in (3.2) above.

[0087] (3.6)Ion process system parameter testing, including: standing wave ratio, insertion loss, return loss, impedance, etc. Combining with the impedance value obtained in the above (3.3), the standing wave ratio, insertion loss, and return loss can be calculated respectively.

[0088] Among them, the standing wave ratio is the ratio of the maximum value to the minimum value of the standing wave on the transmission line, used to measure the impedance matching degree on the transmission line. Specifically, the characteristic impedance of the transmission line is Z 0 (usually this characteristic impedance Z 0 = 50Ω), the load impedance is Z L (this load impedance is the impedance value measured actually, that is, the impedance values of the vacuum reaction chamber and the matcher), then the calculation formula of the standing wave ratio is:

[0089]

[0090] Among them, Γ is the reflection coefficient,

[0091] Insertion loss refers to the signal power loss caused by inserting a component or device in the transmission system, usually expressed in decibels (dB). If the impedance Z of the inserted component and the characteristic impedance Z of the transmission line are known 0 , then the calculation formula of the insertion loss is:

[0092] Return loss is the decibel number of the ratio of the reflected wave power to the incident wave power, which reflects the reflection degree of the signal due to impedance mismatch during transmission. According to the reflection coefficient Γ, the calculation formula of the return loss is: RL = -20log|Γ|.

[0093] (3.7)Arc capture in the plasma vacuum reaction chamber. When an arc appears in the vacuum reaction chamber, the impedance on the overall transmission line will change instantaneously. As long as the sampling rate is high enough, the arc can be captured, and analyzing the frequency of the arc appearance helps to analyze the stability of the overall process.

[0094] Among them, arc capture is: in semiconductor processing, an arc is a phenomenon where due to an overly strong electric field, the gas undergoes electrical breakdown and continuously forms a plasma, and then the current passes through an insulating medium (such as air) under normal conditions. This arc shows an abnormal voltage at the voltage level. Therefore, it is detected at a high-frequency sampling rate of the MHz level. If there is a situation where the voltage drops suddenly and then rises again within a very short time (about several microseconds), it is determined that an arc has occurred.

[0095] As another implementation manner, an expansion unit is also provided in the device proposed in this embodiment, such as Figure 1As shown, this expansion unit, as an additional signal processing part, can provide a connection function for data processing. In this embodiment, the expansion unit includes an expansion data acquisition unit arranged inside the host, and an expansion sensor unit connected to the expansion data acquisition unit. The expansion sensor unit can adopt a VIZ probe, a dual-directional coupling probe, an antenna receiving module, etc. By setting this expansion unit, more function expansions can be provided for the test platform. Its main function is to open more connection ports for sensors and support various different types of sensors according to the actual needs of customers. For example, if one or more identical sensors need to be added, the expansion unit only needs to add the corresponding number of probes to simultaneously detect two or more channels of signals; if a dual-directional coupling probe is added, the expansion unit can also test reverse signals; if a receiving-end antenna is added, the radio frequency leakage in the environment can be tested.

[0096] In this embodiment, an antenna receiving module is arranged in the sensor unit, which can further realize the capture of possible radio frequency leakage in the transmission line. Specifically, the process of capturing the radio frequency leakage is as follows:

[0097] First, prepare the equipment: a biconical antenna or a dipole antenna, and the comprehensive tester proposed in this embodiment.

[0098] Second, arrange the test environment. Place the receiving-end antenna in the environment where radio frequency leakage needs to be tested, such as near equipment that may generate radio frequency leakage, at different distances, etc., to comprehensively evaluate the radio frequency leakage situation in the environment. In addition, ensure that the installation position and direction of the antenna are not interfered by other objects, and try to avoid the influence of metal objects, electromagnetic shielding materials, etc. on the antenna receiving signal.

[0099] After that, collect signals. Turn on the device and set parameters such as the center frequency, scan bandwidth, resolution bandwidth, etc. The center frequency should be set to the frequency or frequency band of the target radio frequency signal. The scan bandwidth needs to be wide enough to cover the frequency range of possible leakage signals, and the resolution bandwidth affects the accuracy of signal measurement. After setting the above parameters, use the antenna receiving module to collect signals (continuous scanning or fixed-point measurement methods can be adopted), and record the radio frequency signal strength received at different positions and time points.

[0100] Then, analyze the data. The signals collected above are transmitted to the expansion data acquisition unit. After the expansion data acquisition unit receives the signals, it transmits the signals to the data processing and analysis unit. The data processing and analysis unit then performs spectral analysis on the signals to identify signal characteristics that may belong to radio frequency leakage (such as path loss, power density, etc.), analyzes signal strength, frequency distribution, time-domain characteristics, etc., and judges the severity and possible sources of radio frequency leakage.

[0101] Among them, calculate the path loss of the signal during propagation to evaluate the intensity attenuation of the signal at different distances. The calculation formula for this path loss is:

[0102] L = 32.45 + 20log10(f) + 20log10(d);

[0103] Among them, L is the path loss, with the unit of dB; f is the signal frequency, with the unit of MHz; d is the propagation distance, with the unit of km.

[0104] In addition, calculate the power density to measure the RF power received per unit area. The calculation formula for this power density is:

[0105] S = P / (4πr 2 );

[0106] Among them, S is the power density, with the unit of W / m 2 ; P is the transmitted power, with the unit of W; r is the distance from the emission source, with the unit of m.

[0107] Finally, result evaluation and reporting. According to the measurement and analysis results, evaluate whether the RF leakage in the environment exceeds the limits of relevant standards or specifications. If there is an over-standard situation, further determine the measures to be taken, such as improving the shielding performance of the equipment, adjusting the position or working parameters of the equipment, etc.

[0108] Through the comprehensive test device proposed in this embodiment, based on fixed or customized probes, and applying it to the ion process system composed of a semiconductor RF power supply, an energy transmission system, an RF power supply matcher, and a plasma vacuum reaction chamber, it can realize the on-line measurement of the forward and reverse power, voltage value, current value, phase value, and impedance of the RF power supply signal. At the same time, it supports signal capture of up to five fundamental frequencies and up to the fourth harmonic at most, arc detection in the vacuum reaction chamber, and analysis of the RF waveform in the time domain during the process. In addition, through the above expansion unit and expansion sensors, a certain degree of expansion can be carried out on the basis of the above basic functions, such as matching network efficiency testing, RF power supply fault analysis, detection of whether there is RF leakage in the test environment, etc.

[0109] Embodiment 2

[0110] This embodiment provides a radio frequency plasma comprehensive test method for an ion process system, which is implemented based on the radio frequency plasma comprehensive test device proposed in Embodiment 1. This method includes:

[0111] Place the coupling probe of the radio frequency plasma comprehensive test device on the RF transmission line of the ion process system, and start the radio frequency plasma comprehensive test device;

[0112] Using a coupling probe, based on the principle of electromagnetic field coupling, the radio frequency energy is coupled and sampled through capacitive or inductive coupling. The current and voltage signals are obtained through coupling, and at the same time, the real-time temperature data inside the probe is sensed and the obtained current, voltage signals and temperature data are transmitted to the host computer;

[0113] Based on the data processing and analysis unit inside the host computer, the received voltage, current and temperature signals are processed, and the radio frequency power supply power, radio frequency power supply spectrum, impedance of the matcher and the vacuum reaction chamber, and other ion process system parameter values are calculated and generated. At the same time, the clutter capture and radio frequency transmission harmonic test results during radio frequency transmission are output.

[0114] The above radio frequency plasma comprehensive test method further includes:

[0115] Using the expansion unit in the radio frequency plasma comprehensive test device, an antenna receiving module is added to the expansion sensor unit of the expansion unit;

[0116] Using the antenna receiving module to collect signals and record the radio frequency signal intensities received at different positions and time points;

[0117] According to the received collected signals, analyze the signal spectrum and identify possible radio frequency leakage in the transmission line.

[0118] Further, the data processing of the received voltage, current and temperature signals includes:

[0119] Perform calculation and adjustment on the amplitudes and phases of the voltage and current signals obtained through coupling;

[0120] According to the real-time obtained temperature data, perform temperature correction on the adjusted voltage and current signals;

[0121] According to the corrected voltage and current signals, calculate the power of the radio frequency power supply, the spectrum of the radio frequency power supply, the impedance of the matcher and the vacuum reaction chamber, the clutter capture during radio frequency transmission, the harmonic test during radio frequency transmission, the arc capture in the plasma vacuum reaction chamber, and the standing wave ratio, insertion loss, return loss, and impedance parameter data in the ion process system.

[0122] Each step involved in the second embodiment above corresponds to that in the first embodiment, and the specific implementation manner can refer to the relevant description part of the first embodiment.

[0123] Those skilled in the art should understand that the above-mentioned modules or steps of the present invention can be implemented by a general-purpose computer device. Optionally, they can be implemented by program codes executable by a computing device, so that they can be stored in a storage device and executed by the computing device, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

[0124] The above are only the preferred embodiments of the present invention. Although the specific implementation manners of the present invention have been described in conjunction with the accompanying drawings, they are not limitations on the protection scope of the present invention. Those skilled in the art should understand that various modifications or deformations that can be made without creative efforts on the basis of the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A radio frequency plasma comprehensive test device for ion process systems, characterized in that: Including main unit and coupling probe; The coupling probe is placed on the RF transmission line of the ion process system, and is used to couple and sample RF energy through capacitance or induction coupling according to the electromagnetic field coupling principle, obtain current and voltage signals through coupling, and to sense and obtain real-time temperature data inside the probe; The host includes a main shell and a shielding frame arranged in the main shell. A data processing and analysis unit is arranged inside the shielding frame. The data processing and analysis unit is used to process the received voltage, current and temperature signals, calculate and generate RF power supply power, RF power supply spectrum, impedance of the matcher and the vacuum reaction chamber and other ion process system parameter values, and output the clutter capture and RF transmission harmonic test results in RF transmission.

2. The radio frequency plasma comprehensive testing device for ion process system according to claim 1, characterized in that: The coupling probe is integrated with a central sensing conductor, a temperature acquisition unit, a current acquisition unit, a voltage acquisition unit and a signal transmission unit; wherein: The central inductive conductor is used to couple and sample the radio frequency energy through capacitive or inductive coupling according to the electromagnetic field coupling principle; The current acquisition unit and the voltage acquisition unit are both electrically connected to the central induction conductor, and are used to obtain the original current and voltage signals according to the coupling sampling results of the central induction conductor; The temperature acquisition unit is a temperature sensor built into the coupling probe, which is used to collect temperature data inside the probe in real time; The signal transmission unit is electrically connected to the host through voltage and current signal transmission lines and temperature signal transmission lines, and is used to transmit the collected voltage, current and temperature signals to the data processing and analysis unit of the host.

3. The radio frequency plasma comprehensive testing device for ion process system according to claim 1, characterized in that: A power supply unit and a mainboard control unit are also provided inside the shielding frame, a display panel and an operation panel are embedded in the main housing, and the power supply unit, the data processing and analysis unit, the display panel, and the operation panel are all electrically connected to the mainboard control unit, wherein: The power supply unit is used to supply power to the entire device; The operation panel is provided with a variety of buttons for generating control signals according to human operation and transmitting the control signals to the mainboard control unit; The display panel uses an LED, LCD or OLED touch screen to display the controllable interface and the content sent by the display mainboard control unit; The mainboard control unit is used to integrate and drive other units to operate.

4. The radio frequency plasma comprehensive testing device for ion process system according to claim 1, characterized in that: The data processing of the received voltage, current and temperature signals includes: Calculate and adjust the amplitude and phase of the voltage and current signals obtained by coupling; Perform temperature correction on the adjusted voltage and current signals according to the temperature data acquired in real time; Based on the corrected voltage and current signals, the power of the RF power supply, the spectrum of the RF power supply, the impedance of the matcher and the vacuum reaction chamber, the clutter capture in RF transmission, the harmonic test in RF transmission, the arc capture in the plasma vacuum reaction chamber, and the standing wave ratio, insertion loss, return loss, and impedance parameter data in the ion process system are calculated at the same time.

5. The radio frequency plasma comprehensive testing device for ion process system according to claim 4, characterized in that: The temperature correction is: Preset the output power of the standard source, adjust the temperature of the temperature control box and collect the data deviation of the coupled voltage and current signals under the condition of temperature deviation; Data fitting is performed based on the collected voltage and current signals at different temperatures to obtain a temperature offset curve and a curve formula; According to the pre-acquired temperature offset curve and curve formula, combined with the real-time acquired temperature data, the adjusted voltage and current signals are temperature corrected to obtain corrected voltage and current signals.

6. The radio frequency plasma comprehensive testing device for ion process system according to claim 1, characterized in that: The device is also provided with an expansion unit, which includes an expansion data acquisition unit arranged inside the host and an expansion sensor unit connected to the expansion data acquisition unit. The expansion sensor unit adopts any one or more sensors of VIZ probe, dual directional coupling probe, antenna receiving module.

7. The radio frequency plasma comprehensive testing device for ion process system according to claim 6, characterized in that: An antenna receiving module is provided in the extended sensor unit, and the antenna receiving module is used to collect signals and record the radio frequency signal strength received at different positions and time points; The extended data acquisition unit is used to receive the acquisition signal and transmit the received signal to the data processing and analysis unit; The data processing and analysis unit is used to analyze the frequency spectrum of the signal and identify possible radio frequency leakage in the transmission line.

8. A radio frequency plasma comprehensive testing method for ion process systems, characterized in that: Based on the radio frequency plasma comprehensive testing device for ion process systems according to any one of claims 1 to 7, the method comprises: Placing a coupling probe of a radio frequency plasma comprehensive test device on a radio frequency transmission line of an ion process system, and starting the radio frequency plasma comprehensive test device; Using a coupling probe, according to the electromagnetic field coupling principle, the RF energy is coupled and sampled by capacitive or inductive coupling, and current and voltage signals are obtained through coupling. At the same time, the real-time temperature data inside the probe is obtained by induction, and the obtained current, voltage signals and temperature data are transmitted to the host; Based on the data processing and analysis unit inside the host, the received voltage, current and temperature signals are processed to calculate and generate the RF power supply power, RF power supply spectrum, impedance of the matcher and vacuum reaction chamber and other ion process system parameter values, and at the same time output the clutter capture in RF transmission and the RF transmission harmonic test results.

9. The radio frequency plasma comprehensive testing method for an ion process system according to claim 8, characterized in that: The data processing of the received voltage, current and temperature signals includes: Calculate and adjust the amplitude and phase of the voltage and current signals obtained by coupling; Perform temperature correction on the adjusted voltage and current signals according to the temperature data acquired in real time; Based on the corrected voltage and current signals, the power of the RF power supply, the spectrum of the RF power supply, the impedance of the matcher and the vacuum reaction chamber, the clutter capture in RF transmission, the harmonic test in RF transmission, the arc capture in the plasma vacuum reaction chamber, and the standing wave ratio, insertion loss, return loss, and impedance parameter data in the ion process system are calculated at the same time.

10. The radio frequency plasma comprehensive testing method for an ion process system according to claim 8, characterized in that: Also includes: Using the expansion unit in the radio frequency plasma comprehensive test device, an antenna receiving module is added to the expansion sensor unit of the expansion unit; The antenna receiving module is used to collect signals and record the RF signal strength received at different locations and time points; Based on the received acquisition signal, the signal spectrum is analyzed to identify possible RF leakage in the transmission line.

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