High-frequency driven high-speed diagnostic electrostatic probe system and method thereof

Abstract

The present invention relates to a high-frequency driven high-speed diagnostic electrostatic probe system and a method thereof and, more specifically, provides a high-frequency driven high-speed diagnostic electrostatic probe system and a method thereof, wherein a high-speed diagnosis for the characteristics of plasma is enabled by using a fitting function without a high impedance choke filter after a plurality of pieces of current waveform data, which are measured by applying a high-frequency bias voltage to a probe while shifting the phase of same, are phase-retrieved and averaged and then processed in accordance with a preset methodology.

Description

High-frequency driven high-speed diagnostic electrostatic probe system and method thereof

[0001] The present invention relates to a high-frequency driven high-speed diagnostic electrostatic probe system and a method thereof. More specifically, the invention relates to a high-frequency driven high-speed diagnostic electrostatic probe system and a method thereof that enables high-speed diagnosis by measuring multiple current waveform data while changing the phase difference of a high-frequency bias voltage on a probe, processing the current waveform data according to a preset methodology after phase restoration and averaging, and then using a fitting function to extract plasma characteristics without a high-impedance choke filter.

[0002] As semiconductor manufacturing processes become more complex and the required precision increases, interest in plasma process diagnosis and control technology is growing.

[0003] Key factors in semiconductor plasma processes (e.g., flux of reactive chemical species (radicals) within the vessel) are closely related to electronic information (plasma density, electron temperature).

[0004] In addition, various methods are being studied to analyze different plasma parameters, such as plasma potential and ion current.

[0005] In particular, as semiconductor manufacturing processes using plasma become more complex, processes in which the plasma state continuously changes are emerging, requiring diagnostic technology capable of monitoring plasma information generated during such plasma transitions. For example, in pulsed plasma, RF power is applied for several milliseconds to form the plasma, and the RF power is removed for several milliseconds to cause the plasma to dissipate.

[0006] Plasma density refers to the number of ionized plasma particles per unit volume, and generally, the number of ions or electrons in the plasma is cm³ 3It refers to how many are inside. Since plasma maintains a quasi-neutral state, the number of electrons and ions are approximately the same.

[0007] Such plasma density can be easily measured using an electrostatic probe, specifically the Langmuir probe method. In the Langmuir probe method, a conductive probe is placed inside a plasma reactor, and when negative and positive potentials are applied to the probe relative to the floating potential, positive ions flow through the probe at a negative potential lower than the floating potential. Above the floating potential, as the applied potential of the probe gradually approaches the plasma potential, an electron current within the plasma flows through the probe. Since the slope of the current increasing with the applied potential is determined by the electron temperature of the electrons within the plasma, the electron temperature can also be measured from this slope. An electron current flows through the probe at an applied potential higher than the plasma potential; the electron current at the plasma potential is called the saturation electron current, from which the plasma density is calculated.

[0008] Figure 1 is a diagram showing the configuration of a conventional electrostatic probe.

[0009] As illustrated in FIG. 1, a conventional electrostatic probe device includes a process chamber (10), a probe (11), an auxiliary ring (13), a high-impedance choke filter (14), a DC voltage application unit (12), and a voltage / current measurement unit (15).

[0010] The measurement principle of plasma characteristics is to insert a probe (11) into the plasma inside the plasma chamber (10) from the outside and vary the external DC power supply to change the voltage from negative potential to positive potential, usually within -200V to 200V. At this time, when a negative voltage is applied to the tip of the probe (11), positive ions in the plasma are captured by the probe and a current is generated by the ions, and when a positive voltage is applied to the tip of the probe, electrons in the plasma are captured by the probe and a current is generated by the electrons.

[0011] Figures 2a and 2b are drawings illustrating the current-voltage curve (IV curve) obtained using the probe device of Figure 1.

[0012] As shown in FIG. 2a, in the case where the plasma is a DC plasma, a bias voltage is applied to the probe (11) through the voltage application unit (12), and ions and electrons (current) in the plasma are extracted according to the bias voltage, so that plasma information can be obtained from the current-voltage curve (IV curve) according to the bias voltage.

[0013] As shown in Fig. 2b, the plasma is an RF plasma, and it forms an electric field in the direction of acceleration for most ions, but conversely, in the direction of deceleration for electrons.

[0014] In the case of electrons, according to the Boltzmann relation, only electrons that overcome the potential formed in the sheath can enter the probe. In the case of ions, since it is in the direction of acceleration, current can enter the probe at a constant value.

[0015] Accordingly, the range of the current-voltage curve (IV curve) widens and the slope decreases, causing the electron temperature to rise and distortion to occur.

[0016] Korean registered patent [10-0663176] discloses a Langmuir plasma diagnostic device.

[0017] Korean published patent [10-2007-0048577] discloses a plasma diagnostic device and a diagnostic method.

[0018] Korean registered patent [10-1355728] discloses a method for controlling plasma treatment using parameters derived through the use of a planar ion flux probing device.

[0019] Korean published patent [10-2014-0112586] discloses a plasma diagnostic method and apparatus.

[0020] (Patent Document 1) Korean Registered Patent [10-0663176] (Registration Date: Dec. 22, 2006)

[0021] (Patent Document 2) Korean Published Patent [10-2007-0048577] (Publication Date: May 9, 2007)

[0022] (Patent Document 3) Korean Registered Patent [10-1355728] (Registration Date: 2014. 01. 20)

[0023] (Patent Document 4) Korean Published Patent [10-2014-0112586] (Publication Date: September 24, 2014)

[0024] (Non-patent Document 1) Petr Sezemsky “Modified high frequency probe approach for diagnostics of highly reactive plasma” 2019 Plasma Sources Sci. Technol. 28 115009

[0025] The objective of the present invention is to provide a high-frequency driven high-speed diagnostic electrostatic probe system and a method thereof that can diagnose plasma characteristics at high speed without a high-impedance choke filter by measuring multiple current waveform data while changing the phase difference of the high-frequency bias voltage on the probe, then processing the phase after restoration and averaging according to a preset methodology, and finally using a fitting function.

[0026] The purposes of the embodiments of the present invention are not limited to those mentioned above, and other unmentioned purposes will be clearly understood by those skilled in the art from the description below.

[0027] A high-frequency driven high-speed diagnostic electrostatic probe system according to one embodiment of the present invention comprises: a probe inserted into a process chamber to diagnose plasma generated in the process chamber; and a sinusoidal high-frequency bias voltage (V) applied to the probe. BA high-frequency voltage application unit for applying ); phase-shifted bias signals (V) synchronized with the plasma potential by converting the high-frequency bias voltage to have a phase difference that is an integer multiple of a unit phase difference according to a preset number. BP A phase control unit that outputs ); the phase conversion bias signals (V BP For each of the above, the total current signal (I) flowing through the probe tot A measuring unit for measuring (t); a plurality of total current signals (I) measured above. tot (t)) phase-recovers and averages the average total current signal (I tot,avg Data averaging unit for obtaining (t')); the average total current signal (I tot,avg It includes a data processing unit for obtaining a current-voltage curve by processing (t'); a curve fitting unit for setting and fitting a fitting range, which is a range of voltages where the slope of the current changes exponentially, using a fitting function on the obtained current-voltage curve; and a calculation unit (900) for calculating electron temperature and electron density using the fitting function.

[0028] A measurement method of a high-frequency driven high-speed diagnostic electrostatic probe according to an embodiment of the present invention comprises: a plasma generation step (S10) of inserting a probe into a process chamber and then applying power to the process chamber to generate plasma; and a high-frequency bias voltage (V) applied to the probe. B Phase transformation bias signals (V) synchronized with the plasma potential (Vp) by converting ) to have a phase difference (Δφ × n) that is an integer multiple (n) of the unit phase difference (Δφ = 2π / k) according to a preset number (k). BP A phase control step (S20) that outputs ); the phase conversion bias signals (V) to the probe BP For each of the above, the total current signal (I) flowing through the probe tot A measurement step (S30) for measuring each of the (t)); a plurality of total current signals (I) measured above. tot(t)) phase restored and averaged average total current signal (I tot,avg A data averaging step (S40) for obtaining (t')); the average total current signal (I tot,avg The method includes a data processing step (S50) for obtaining a current-voltage curve (IV curve) by processing (t'); a curve fitting step (S60) for setting and fitting a fitting range, which is a range of voltages where the slope of the current changes exponentially, using a fitting function on the obtained current-voltage curve; and a calculation step (S70) for calculating electron temperature and electron density using the fitting function.

[0029] In addition, according to one embodiment of the present invention, a computer-readable recording medium is provided that stores a program for implementing the high-frequency driven high-speed diagnostic electrostatic probe method.

[0030] In addition, according to one embodiment of the present invention, a program stored on a computer-readable recording medium is provided to implement the high-frequency driven high-speed diagnostic electrostatic probe method.

[0031] According to a high-frequency driven high-speed diagnostic electrostatic probe system and method according to one embodiment of the present invention, a plurality of measured current waveform data are applied to a probe while changing the phase, and after phase restoration and averaging, processed according to a preset methodology and using a fitting function, the effect of diagnosing the characteristics of plasma at high speed without a high-impedance choke filter is achieved.

[0032] In addition, according to the high-frequency driven high-speed diagnostic electrostatic probe system and method according to one embodiment of the present invention, it is possible to verify electron density, electron temperature, and mismatch by simulating the magnitude and frequency range of the high-frequency bias voltage applied to the probe, thereby having the effect of knowing the optimal magnitude and frequency range of the high-frequency bias voltage that enables ultra-high-speed diagnosis without a high-impedance choke filter.

[0033] In addition, according to the high-frequency driven high-speed diagnostic electrostatic probe system and method of one embodiment of the present invention, the number of current data to be collected can be simulated by measuring while changing the phase difference between the high-frequency bias voltage and the plasma potential, thereby allowing verification of electron density, electron temperature, and discrepancy, and thus the number of data to be collected can be optimized.

[0034] In addition, according to one embodiment of the present invention, the high-frequency driven high-speed diagnostic electrostatic probe system and method thereof, when driven with an RF bias of 1 MHz within a discrepancy of less than 5%, it takes 100 μs to collect 100 data, and compared to the data collection time of several ms of a conventional electrostatic probe device (Langmuir probe), it has the effect of enabling high-speed diagnosis of plasma.

[0035] Figure 1 is a configuration diagram of a conventional electrostatic probe.

[0036] FIGS. 2a and 2b are drawings illustrating a current-voltage curve (IV curve) obtained using the probe device of FIG. 1.

[0037] FIG. 3 is a configuration diagram of a high-frequency driven high-speed diagnostic electrostatic probe system according to one embodiment of the present invention.

[0038] FIG. 4 is a flowchart illustrating the operation method of a high-frequency driven high-speed diagnostic electrostatic probe system according to one embodiment of the present invention of FIG. 3.

[0039] Figure 5 is a diagram showing a high-frequency bias voltage and a phase-shifted bias signal with k=3.

[0040] Figure 6 is a diagram showing a high-frequency bias voltage and a phase-shifted bias signal with k=500.

[0041] Figure 7 shows the phase-restored total current and the averaged total current.

[0042] Figure 8 shows the average total current with respect to the voltage axis.

[0043] Figure 9 is a graph showing the average total current and the fitting function.

[0044] Figures 10a to 10h show current-voltage curves according to the number of current waveforms (number of averaged data).

[0045] Figure 11a shows the simulation results representing electron density and electron temperature according to the number of averaged data (k).

[0046] Figure 11b is a simulation result showing the degree of discrepancy between electron density and electron temperature according to the number of averaged data (k).

[0047] Figure 12a shows the simulation results representing electron density and electron temperature according to the frequency of the bias voltage.

[0048] Figure 12b is a simulation result showing the degree of discrepancy between electron density and electron temperature according to the frequency of the bias voltage.

[0049] Figure 13a shows the simulation results representing electron density and electron temperature according to the amplitude of the plasma potential.

[0050] Figure 13b is a simulation result showing the discrepancy between electron density and electron temperature according to the amplitude of the plasma potential.

[0051] When measuring an RF pulse plasma that changes rapidly over time with a period during which the plasma is periodically turned on for several milliseconds and then turned off after several milliseconds, it is necessary to measure the change in plasma density over time within several milliseconds. The plasma density over time can be measured during the turn-on and turn-off periods of the RF pulse plasma.

[0052] The high-frequency driven high-speed diagnostic electrostatic probe system of the present invention uses a high-frequency bias voltage (V) having a bias frequency of several hundred kHz to several MHz for plasma density that changes rapidly over time. B It can be measured using ) and averaging techniques. Meanwhile, the driving frequency of the RF power supply forming the plasma can be tens of times or more than the bias frequency.

[0053] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the invention to specific embodiments, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0054] When it is stated that one component is "connected" or "joined" to another component, it should be understood that while it may be directly connected or joined to that other component, there may also be other components in between.

[0055] On the other hand, when it is stated that one component is "directly connected" or "directly coupled" to another component, it should be understood that there are no other components in between.

[0056] The terms used in this specification are used merely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, processes, operations, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, processes, operations, components, parts, or combinations thereof.

[0057] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0058] The present invention will be described in more detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best describe their invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Furthermore, unless otherwise defined, technical and scientific terms used shall have the meaning commonly understood by those skilled in the art to which this invention pertains. Descriptions of known functions and configurations that could unnecessarily obscure the essence of the present invention in the following description and attached drawings are omitted. The drawings presented below are provided as examples to ensure that the spirit of the present invention is sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below and may be embodied in other forms. Additionally, throughout the specification, the same reference numerals indicate the same components. It should be noted that the same components in the drawings are represented by the same reference numerals wherever possible.

[0059] FIG. 3 is a configuration diagram of a high-frequency driven high-speed diagnostic electrostatic probe system according to one embodiment of the present invention.

[0060] FIG. 4 is a flowchart illustrating the operation method of a high-frequency driven high-speed diagnostic electrostatic probe system according to one embodiment of the present invention of FIG. 3.

[0061] Figure 5 is a diagram showing a high-frequency bias voltage and a phase-shifted bias signal with k=3.

[0062] Figure 6 is a diagram showing a high-frequency bias voltage and a phase-shifted bias signal with k=500.

[0063] Figure 7 shows the phase-restored total current and the averaged total current.

[0064] Figure 8 shows the average total current with respect to the voltage axis.

[0065] Figure 9 is a graph showing the average total current and the fitting function.

[0066] As illustrated in FIGS. 3 to 9, a high-frequency driven high-speed diagnostic electrostatic probe system (1000) according to one embodiment of the present invention comprises a process chamber (100), a probe (200), a high-frequency bias voltage application unit (300), a phase control unit (400), a current / voltage measurement unit (500), a phase restoration unit (601), a data averaging unit (600), a data processing unit (700), a curve fitting unit (800), and a calculation unit (900).

[0067] A high-frequency driven high-speed diagnostic electrostatic probe system (1000) according to one embodiment of the present invention comprises: a probe (200) inserted into the process chamber (100) to diagnose plasma generated in the process chamber; and a sinusoidal high-frequency bias voltage (V) applied to the probe. B A high-frequency bias voltage application unit (300) for applying ); the high-frequency bias voltage (V B Phase transformation bias signals (V) synchronized with the plasma potential by converting ) to have a phase difference that is an integer multiple of the unit phase difference according to a preset number BP A phase control unit (400) that outputs ); the phase conversion bias signals (V BP For each of the above, the total current signal (I) flowing through the probe tot A current / voltage measuring unit (500) for measuring (t); a plurality of total current signals (I) measured above. tot (t)) phase-recovers and averages the average total current signal (I tot,avg Data averaging unit (601, 600) for obtaining (t')); the average total current signal (I tot,avgIt includes a data processing unit (700) for processing (t')) to obtain a current-voltage curve (IV curve); a curve fitting unit (800) for using a fitting function on the obtained current-voltage curve to set a fitting range for the voltage range where the slope of the current changes exponentially and to fit; and a calculation unit (900) for calculating electron temperature and electron density using the fitting function.

[0068] The process chamber (100) is a space in which RF plasma is generated upon the application of RF power from an RF power source (32). The plasma may be an RF inductively coupled plasma or an RF capacitively coupled plasma. The frequency of the RF power source (32) may be 13.56 MHz or higher. The RF power source (32) applies RF power to an induction coil (34) through an impedance matching network (33). The induction coil (34) may form an induced electric field at the bottom of a dielectric window covering the upper surface of the process chamber (100) by means of the applied RF power. The induced electric field may form an inductively coupled plasma. The process chamber (100) may perform various processes such as etching or deposition. The plasma potential (Vp) of the RF plasma may fluctuate in synchronization with the RF frequency of the RF power source (32).

[0069] The probe (200) is inserted into the process chamber (100) to diagnose the plasma generated in the process chamber. The tip of the probe (200) is an exposed metal and may have a form in which the metal is wrapped in an insulator. The exposed metal tip of the probe (200) is exposed to the plasma to capture electrons or ions, thereby allowing current to flow.

[0070] The high-frequency bias voltage application unit (300) applies a high-frequency bias voltage (V) to the probe (200). B ) is applied. The above high-frequency bias voltage (V B) is a sinusoidal wave, and its amplitude can be at the level of tens of volts. The above high-frequency bias voltage (V B The bias frequency of ) can be sufficiently smaller than the frequency of the RF power supply (32) forming the RF plasma. For example, if the frequency of the RF power supply (32) is 13.56 MHz, the high-frequency bias voltage (V B The bias frequency of ) may be at the level of 400 kHz to 1 MHz. Or, the high-frequency bias voltage (V B The bias frequency of ) can be 100 kHz to 2 MHz.

[0071] The above phase control unit (400) is the high-frequency bias voltage (V B The high-frequency bias voltages output sequentially can be divided into cycles and output sequentially. The high-frequency bias voltages output sequentially may have different phase differences. The phase difference may be an integer multiple (φ = Δφ × n) of the unit phase difference (Δφ = 2π / k) obtained by dividing one cycle (or 2π) of the high-frequency bias voltage by a preset number (k). The preset number (k) may be the number of current measurements for averaging.

[0072] That is, the phase control unit (400) is the high-frequency bias voltage (V B The phase of ) is transformed to have a phase difference (φ) that is an integer multiple (n) of the unit phase difference (Δφ = 2π / k) obtained by dividing 2π by the aforementioned preset number (k), as shown in [Mathematical Equation 1] below, thereby transforming the phase transformation bias signals (V BP Can output ).

[0073] [Mathematical Formula 1]

[0074] φ = Δφ × n

[0075] Here, Δφ = 2π / k is a unit phase difference, n is a positive integer in the range of zero to k, and k is the number of measurements to be averaged for the current. k can be 100 to 500. The phase-shifted bias signals (V) having different phase differencesBP Each of these can be synchronized with an RF power source (32) or a plasma potential (Vp).

[0076] Referring to FIG. 5, for example, when k=3, 2π is divided by 3, and the unit phase difference (Δφ=2π / 3) can be 120 degrees. Accordingly, the phase-shifted bias signals (V) that are sequentially output BP The phase difference of ) can be 0 degrees, 120 degrees, or 240 degrees. The phase-shifted bias signals (V) having a phase difference of 0 degrees. BP ) can have a cosine waveform. The phase-shifted bias signals (V) having a phase difference of 120 degrees BP ) can have a sinusoidal waveform of one period with a phase delay of 120 degrees. The phase-shifted bias signals (V) having a phase difference of 240 degrees BP ) can have a sinusoidal waveform of one period with a phase delay of 240 degrees.

[0077] Accordingly, the total current (I) flowing through the probe tot (V BP )) are phase shift bias signals (V BP The inventor believes that it depends on ) and plasma potential (Vp) and will be given as follows.

[0078] [Mathematical Formula 1-2]

[0079]

[0080] Here, Te is the electron temperature, and Vp is the plasma potential. Iisat is the ion saturation current, and Iesat is the current saturation current. Csh is the capacitance of the probe sheath between the probe and the plasma. Vp is the plasma potential and is synchronized with the RF power source (32) and can fluctuate at the driving frequency of the RF power source. An averaging step is performed to remove the driving frequency component of the RF power source from the plasma potential (Vp).

[0081] Referring to FIG. 6, for example, when k=500, 2π is divided by 500, and the unit phase difference (Δφ=2π / 500) can be 0.72 degrees. Accordingly, the phase-shifted bias signals (V) that are sequentially output BP The phase difference of ) can be 0 degrees, 0.72 degrees,... The phase-shifted bias signals (V) having a phase difference of 0 degrees. BP ) can have a cosine waveform. The phase-shifted bias signals (V) having a phase difference of 0.72 degrees. BP ) can have a sinusoidal waveform of one period with a phase delay of 0.72 degrees. Accordingly, the total current (I flowing through the probe) tot (V BP )) are phase shift bias signals (V BP Can rely on ).

[0082] The current / voltage measuring unit (500) measures the phase conversion bias signals (V) having a phase difference. BP ) The total current (I) flowing through the probe (200) in each of the above probes (200) tot (t)) can be measured according to time (t) for one period. The current / voltage measuring unit (500) measures phase conversion bias signals (V BP ) can be measured as a function of time (t). Phase shift bias signal (V BP (t)) is the total current (I tot It can be used to change the time axis to the voltage axis in (t).

[0083] The above current / voltage measuring unit (500) is the phase-shifted plurality of high-frequency bias voltages (V BP Regarding ), current data according to the voltage applied to the probe is measured. The current / voltage measuring unit (500) may include an oscilloscope.

[0084] Referring to Fig. 7, the simulation conditions are as follows: the plasma potential frequency is 13.56 MHz, the plasma potential amplitude is 10 V, the plasma potential DC offset is 15 V, the bias voltage frequency is 400 kHz, and the bias voltage (V B The amplitude of ) is 30 V, and the calculated electron density is 10 10 cm -3 and the electron temperature is 3 eV.

[0085] The data averaging unit (600) may include a phase restoration unit (601). The phase restoration unit (601) may restore the measured signal by digital signal processing within a computer after the signal has been converted into a digital signal. The phase restoration unit (601) includes phase transformation bias signals (V BP Corresponding to each of the above-mentioned multiple total current signals (I tot The phase difference (φ = Δφ × n) of (t) can be verified. The phase restoration unit (601) restores the phase using the restored phase difference, which is the value obtained by subtracting the phase difference (φ = Δφ × n) from 2π, as the initial value, thereby restoring the total current signal (I tot (t')) can be obtained. Phase-restored total current signal (I tot (t')) can have a U-shaped current waveform depending on time (t').

[0086] Referring to FIG. 7, the data averaging unit (600) is a phase-restored total current signal (I tot The average total current signal (I) obtained by adding up all (t')) tot,avg (t')) can be generated. Accordingly, the time dependence of the plasma potential in [Equation 1-2] is eliminated. The data averaging unit (600) obtains average data for the multiple measured current data. Total current signal (I tot,avg (t')) may include backward and forward signals depending on the time interval.

[0087] Referring to Fig. 8, the simulation conditions are as follows: the plasma potential frequency is 13.56 MHz, the plasma potential amplitude is 10 V, the plasma potential DC offset is 15 V, the bias voltage frequency is 400 kHz, and the bias voltage (V B The amplitude of ) is 30 V, and the calculated electron density is 10 10 cm -3 And, the electron temperature is 3 eV. The data averaging unit (600) averaged 500 current waveform data.

[0088] The data processing unit (700) processes the average data according to a preset methodology to obtain a current-voltage curve (IV curve). The data processing unit (700) obtains an averaged average total current signal (I tot,avg The x-axis of (t')) is the voltage (V BP It can be performed by converting to the ) axis. That is, the averaged total current signal (I tot,avg (V BP )) is the phase shift bias signal (V BP With respect to the ) axis, the negative voltage can have different values ​​in the backward and forward directions. The data processing unit (700) has the averaged total current signal (I) in the backward direction. tot,avg (backword)) and the averaged total current signal (I tot,avg The final current-voltage curve of the present invention can be obtained by averaging (forward)). Although the data was processed using the Sezemsky methodology, other methodologies may also be used.

[0089] Referring to Fig. 9, the simulation conditions are as follows: the plasma potential frequency is 13.56 MHz, the plasma potential amplitude is 10 V, the plasma potential DC offset is 15 V, the bias voltage frequency is 400 kHz, and the bias voltage (V B The amplitude of ) is 30 V, and the calculated electron density is 1010 cm -3 And, the electron temperature is 3 eV. The data averaging unit (600) averaged 500 current waveform data. The dashed DC graph is a simulation result showing the current-voltage curve when the frequency of the bias voltage is zero.

[0090] It can be seen that the current-voltage curve obtained through the Sezemsky methodology is very similar to the ideally measured current-voltage curve (ideal conduction current).

[0091] The fitting range is determined based on the voltage at which the slope changes in the current-voltage curve using the Sezemsky methodology.

[0092] That is, using a fitting function on the aforementioned current-voltage curve, the range from the minimum voltage to the voltage where the slope changes is determined as the fitting range.

[0093] The curve fitting unit (800) determines the range from the minimum voltage to the voltage where the slope changes in the acquired current-voltage curve as the fitting range. The curve fitting unit (800) uses a fitting function. The curve fitting unit (800) uses a phase-shifting bias signal (V BP The electron temperature (Te) of the exponential function can be obtained by fitting the y-axis to the ) axis. The interval for obtaining the electron temperature (Te) may be the range of the interval fitted by the exponential function.

[0094] Average total current I flowing through the probe (200) tot,avg (V BP I think that ) can be expressed as shown in [Mathematical Equation 2] below.

[0095] [Mathematical Formula 2]

[0096]

[0097] Here, I isat is the ion saturation current, and I esat is the electron saturation current, and VBP is the phase-shifted high-frequency bias voltage, and V p is the plasma potential (plasma potential of the offset), and T e is the electronic temperature.

[0098] The above fitting function is expressed as shown in [Equation 3] below.

[0099] [Mathematical Formula 3]

[0100]

[0101] (here, n e is the electron density, and u B is the Bohm velocity, and A tip is the area of ​​the probe, and Te is the electron temperature.)

[0102] The above electron temperature (Te) is the B value, and the above electron density (n e ) is calculated using the following [Equation 4].

[0103] [Mathematical Formula 4]

[0104]

[0105] The calculation unit (900) can convert the extracted value into electron temperature and electron density using a fitting function and display and store the plasma variable on a display, etc.

[0106] The high-frequency driven high-speed diagnostic electrostatic probe method according to the present invention, considering the number of current waveforms to be measured (number of data to be averaged), the magnitude of the high-frequency bias voltage, the frequency of the high-frequency bias, and the amplitude of the plasma potential, the electron temperature (Te) and the electron density (n e ) can be extracted.

[0107] Meanwhile, the high-frequency driven high-speed diagnostic electrostatic probe system according to the present invention may further include a simulation unit that calculates the discrepancy and the coefficient of determination (R-square) according to simulation conditions. The simulation conditions may include the number of current waveforms to be measured, the magnitude of the high-frequency bias voltage, and the frequency of the high-frequency bias.

[0108] Referring to FIG. 5, the measurement method of a high-frequency driven high-speed diagnostic electrostatic probe according to the present invention comprises: a plasma generation step (S10) of inserting a probe (200) into a process chamber (100) and then applying a power source (32) to the process chamber (100) to generate plasma;

[0109] High-frequency bias voltage (V) applied to the probe (200) above B Phase transformation bias signals (V) synchronized with the plasma potential (Vp) by converting ) to have a phase difference (Δφ × n) that is an integer multiple (n) of the unit phase difference (Δφ = 2π / k) according to a preset number (k). BP A phase control step (S20) that outputs ); and the phase conversion bias signals (V) to the probe (200). BP For each of the above, the total current signal (I) flowing through the probe (200) tot A measurement step (S30) for measuring each of the (t)); a plurality of total current signals (I) measured above. tot (t)) phase restored and averaged average total current signal (I tot,avg A data averaging step (S40) for obtaining (t')); the average total current signal (I tot,avg The method includes a data processing step (S50) for obtaining a current-voltage curve (IV curve) by processing (t'); a curve fitting step (S60) for setting and fitting a fitting range, which is a range of voltages where the slope of the current changes exponentially, using a fitting function on the obtained current-voltage curve; and a calculation step (S70) for calculating electron temperature and electron density using the fitting function.

[0110] Figures 10a to 10h show current-voltage curves according to the number of current waveforms (number of averaged data).

[0111] Referring to FIGS. 10a through 10h, the simulation conditions are as follows: the plasma potential frequency is 13.56 MHz, the plasma potential amplitude is 10 V, the plasma potential DC offset is 15 V, the bias voltage frequency is 400 kHz, and the bias voltage (V B The amplitude of ) is 30 V, and the calculated electron density is 10 10 cm -3 And, the electron temperature is 3 eV. The DC graph is a simulation result showing the current-voltage curve when the frequency of the bias voltage is zero.

[0112] Current-voltage curves and fitting curves were plotted by simulating cases where the number of data points to be averaged (k) was 1, 3, 5, 7, 10, 50, 100, and 500.

[0113] When averaging approximately 100 or more data points, it can be seen that the acquired current-voltage curve appears very similar to the ideal value.

[0114] Figure 11a shows the simulation results representing electron density and electron temperature according to the number of averaged data (k).

[0115] Figure 11b is a simulation result showing the degree of discrepancy between electron density and electron temperature according to the number of averaged data (k).

[0116] As shown in FIGS. 11a and 11b, the simulation conditions are as follows: the plasma potential frequency is 13.56 MHz, the plasma potential amplitude is 10 V, the plasma potential DC offset is 15 V, the bias voltage frequency is 400 kHz, and the bias voltage (V B The amplitude of ) is 30 V, and the calculated electron density is 10 10 cm-3 and the electron temperature is 3 eV.

[0117] The discrepancy of electron temperature and electron density is 5% (percent) or less when the number of averaged data (k) is 100 or more. Preferably, the number of averaged data (k) can be 100 to 500.

[0118] Figure 12a shows the simulation results representing electron density and electron temperature according to the frequency of the bias voltage.

[0119] Figure 12b is a simulation result showing the degree of discrepancy between electron density and electron temperature according to the frequency of the bias voltage.

[0120] As shown in FIGS. 12a and 12b, the simulation conditions are that the plasma potential frequency is 13.56 MHz, the plasma potential amplitude is 10 V, the plasma potential DC offset is 15 V, and the bias voltage (V B The amplitude of ) is 30 V, and the calculated electron density is 10 10 cm -3 And, the electron temperature is 3 eV. This is the case where the frequency of the bias voltage was varied to 400 kHz, 1 MHz, 2 MHz, 5 MHz, and 13.56 MHz. The number of averaged data points is 100.

[0121] It can be seen that for the discrepancy to be 5% or less, it is satisfied when the bias voltage frequency is approximately 1 MHz or less.

[0122] Figure 13a shows the simulation results representing electron density and electron temperature according to the amplitude of the plasma potential.

[0123] Figure 13b is a simulation result showing the discrepancy between electron density and electron temperature according to the amplitude of the plasma potential.

[0124] As shown in FIGS. 13a and 13b, the simulation conditions are as follows: the plasma potential frequency is 13.56 MHz, the plasma potential DC offset is 30 V, and the bias voltage (V B The amplitude of ) is 30 V, and the calculated electron density is 10 10 cm -3 And, the electron temperature is 3 eV. The frequency of the bias voltage is 1 MHz. The number of averaged data points is 100. This is the case where the amplitude of the plasma potential is varied to 0V, 5V, 10V, 20V, 25V, and 30V.

[0125] It can be seen that for the discrepancy to be 5% or less, the plasma potential amplitude is approximately 10V or less.

[0126] Although a high-frequency driven high-speed diagnostic electrostatic probe method according to one embodiment of the present invention has been described above, it is obvious that a computer-readable recording medium storing a program for implementing the high-frequency driven high-speed diagnostic electrostatic probe method and a program stored on the computer-readable recording medium for implementing the high-frequency driven high-speed diagnostic electrostatic probe method can also be implemented.

[0127] That is, those skilled in the art will readily understand that the high-frequency driven high-speed diagnostic electrostatic probe method described above may be provided by being tangibly implemented as a program of instructions for implementing it, and included in a computer-readable recording medium. In other words, it may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable recording medium. The computer-readable recording medium may include program instructions, data files, data structures, etc., either individually or in combination. The program instructions recorded on the computer-readable recording medium may be those specifically designed and configured for the present invention, or they may be those known and available to those skilled in computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks, and magnetic tapes; optical recording media such as CD-ROMs and DVDs; magneto-optical media such as floptical disks; and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and USB memory. Examples of program instructions include machine code, such as that generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc. The hardware device may be configured to operate as one or more software modules to perform the operation of the present invention, and vice versa.

[0128] The present invention is not limited to the embodiments described above, and its scope of application is diverse. Furthermore, it is understood that various modifications are possible without departing from the essence of the invention as claimed in the claims.

Claims

1. In a high-frequency driven high-speed diagnostic electrostatic probe system, A probe inserted into the process chamber to diagnose the plasma generated in the process chamber; A sinusoidal high-frequency bias voltage (V) to the above probe B High-frequency voltage application unit for applying ); The above high-frequency bias voltage is converted to have a phase difference that is an integer multiple of a unit phase difference according to a preset number, thereby providing phase-shifted bias signals (V) synchronized with the plasma potential. BP Phase control unit that outputs ); The above phase transformation bias signals (V BP For each of the above, the total current signal (I) flowing through the probe tot A measuring unit that measures (t); The above-measured multiple total current signals (I tot (t)) phase-recovers and averages the average total current signal (I tot,avg Data averaging unit for obtaining (t')); The above average total current signal (I tot,avg A data processing unit for obtaining a current-voltage curve by processing (t')); A curve fitting unit that sets and fits a fitting range, which is a range of voltages where the slope of the current changes exponentially, using a fitting function on the current-voltage curve obtained above; and A high-frequency driven high-speed diagnostic electrostatic probe system characterized by including a calculation unit (900) for calculating electron temperature and electron density using the above fitting function.

2. In Paragraph 1, The above phase control unit is, A high-frequency driven high-speed diagnostic electrostatic probe system characterized by converting the phase of the above high-frequency bias voltage to have a phase difference that is an integer multiple (n) of the unit phase difference (Δφ=2π / k) obtained by dividing 2π by the above-predetermined number (k), as shown in [Mathematical Formula 1] below. [Mathematical Formula 1] φ = Δφ × n Here, Δφ is a unit phase difference, n is a positive integer in the range from zero to k, and k is the number of measurements to average the current.

3. In Paragraph 1, The data averaging department is: Phase shift bias signals (V BP Corresponding to each of the above-mentioned multiple total current signals (I tot Check the phase difference (φ = Δφ × n) of (t), and The total current signal (I) is phase-restored using the restored phase difference, given as the value obtained by subtracting the above phase difference (φ = Δφ × n) from 2π, as the initial value. tot A high-frequency driven high-speed diagnostic electrostatic probe system characterized by acquiring (t')).

4. In Paragraph 1, The above high-frequency bias voltage (V B A high-frequency driven high-speed diagnostic electrostatic probe system characterized by a bias frequency of 100 kHz to 2 MHz.

5. In Paragraph 4, The above phase transformation bias signals (V BP ) has a preset number, A high-frequency driven high-speed diagnostic electrostatic probe system characterized by the above-mentioned preset number being 100 to 500.

6. In a measurement method for a high-frequency driven high-speed diagnostic electrostatic probe, A plasma generation step (S10) of generating plasma by applying power to the process chamber after inserting a probe into the process chamber; High-frequency bias voltage (V) to the above probe B Phase transformation bias signals (V) synchronized with the plasma potential (Vp) by converting ) to have a phase difference (Δφ × n) that is an integer multiple (n) of the unit phase difference (Δφ = 2π / k) according to a preset number (k). BP Phase control step (S20) that outputs ); The phase shift bias signals (V) to the probe BP For each of the above, the total current signal (I) flowing through the probe tot A measurement step (S30) for measuring each (t); The above-measured multiple total current signals (I tot (t)) phase restored and averaged average total current signal (I tot,avg A data averaging step (S40) for obtaining (t')); The above average total current signal (I tot,avg A data processing step (S50) for obtaining a current-voltage curve (IV curve) by processing (t')); A curve fitting step (S60) for setting and fitting a fitting range, which is a range of voltages where the slope of the current changes exponentially, using a fitting function on the current-voltage curve obtained above; and A measurement method for a high-frequency driven high-speed diagnostic electrostatic probe, characterized by including a calculation step (S70) for calculating electron temperature and electron density using the above fitting function.

7. In Paragraph 6, In the above phase conversion step (S20), A measurement method for a high-frequency driven high-speed diagnostic electrostatic probe, characterized by converting the phase of the high-frequency bias voltage to have a phase difference that is an integer multiple (n) of the unit phase difference (Δφ=2π / k) obtained by dividing 2π by the predetermined number (k), as shown in [Mathematical Formula 1] below. [Mathematical Formula 1] φ = Δφ × n Here, Δφ is a unit phase difference, n is a positive integer in the range from zero to k, and k is the number of measurements to average the current.

8. In Paragraph 6, The average total current signal (I) flowing through the probe tot,avg (V BP )) is expressed as in [Mathematical Formula 2] below, and [Mathematical Formula 2] Here, I isat is the ion saturation current, and I esat is the electron saturation current, and V BP is the phase-shifted high-frequency bias voltage, and V p is the plasma potential, and T e is the electronic temperature. The above fitting function is expressed as shown in [Equation 3] below. [Mathematical Formula 3] (here, n e is the electron density, and u B is the Bohm velocity, and A tip is the area of ​​the probe, and Te is the electron temperature.) The above electron temperature (Te) is the B value, and the above electron density (n e A measurement method for a high-frequency driven high-speed diagnostic electrostatic probe characterized by being calculated using the following [Mathematical Formula 4]. [Mathematical Formula 4] 9. In Paragraph 6, The data averaging step is: Phase shift bias signals (V BP Corresponding to each of the above-mentioned multiple total current signals (I tot Check the phase difference (φ = Δφ × n) of (t), and The total current signal (I) is phase-restored using the restored phase difference, given as the value obtained by subtracting the above phase difference (φ = Δφ × n) from 2π, as the initial value. tot A measurement method of a high-frequency driven high-speed diagnostic electrostatic probe characterized by obtaining (t')).

10. In Paragraph 6, The above high-frequency bias voltage (V B A measurement method for a high-frequency driven high-speed diagnostic electrostatic probe, characterized in that the bias frequency of ) is 100 kHz to 2 MHz.

11. In Paragraph 6, The above phase transformation bias signals (V BP ) has a preset number, A measurement method for a high-frequency driven high-speed diagnostic electrostatic probe, characterized in that the above-mentioned preset number is 100 to 500.

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