Plasma parameter diagnosis device and method

Abstract

A plasma parameter diagnosis device according to an embodiment of the disclosed invention may comprise: a signal generation unit that generates a voltage; a probe unit inserted into a chamber and configured to apply the voltage generated in the signal generation unit to a plasma sheath in the chamber; a sensing element, one end of which is connected to the probe unit so that a current generated from the plasma flows into the sensing element; and a signal transfer unit configured to transfer the voltage generated from the signal generation unit to the probe unit.

Description

Plasma variable diagnosis device and method

[0001] The present invention relates to a plasma variable diagnosis device and method, and more particularly, to a plasma variable diagnosis device and method that improves measurement accuracy by preventing dispersion of an applied voltage by a sensing element.

[0002] Plasma is an ionized gas composed of positive and negative ions, electrons, excited atoms, molecules, and chemically highly active radicals. It has electrical and thermal properties that are very different from those of ordinary gases, and is therefore also called the fourth state of matter. Because plasma contains ionized gases, it is very useful in semiconductor manufacturing processes, such as accelerating them using electric or magnetic fields or inducing chemical reactions to clean, etch, or deposit wafers or substrates.

[0003] Because the density or electron temperature of plasma plays a significant role in the results of semiconductor and display processes, accurately measuring the density or electron temperature of plasma is an essential field in research fields utilizing plasma.

[0004] Typically, a probe is inserted inside the chamber, and plasma variables such as plasma density and electron temperature are measured based on the current flowing through the probe. A representative technique is to analyze the harmonic components of the electron current flowing through the probe at a floating potential.

[0005] However, when measuring the harmonic current of the current according to the conventional technology, there is a problem that an error in the plasma variable measurement value occurs because the applied voltage is distributed not only to the plasma but also to the sensing element installed inside the circuit for current measurement during the process of applying a sinusoidal voltage to the plasma.

[0006] In addition, since the first harmonic current and the second harmonic current flowing from the plasma are proportional to the plasma sheath applied voltage value and its square value, respectively, if an error occurs in the applied voltage, an error in the plasma variable measurement value based on the harmonic current measurement also occurs significantly.

[0007] Accordingly, the plasma variable diagnosis device and method according to one embodiment of the disclosed invention is an invention created to solve the above-described problem, and more specifically, can provide an improved plasma variable diagnosis device and method so that the entire input voltage of the diagnosis circuit can be applied to the plasma sheath.

[0008] In addition, the plasma variable diagnosis device and method according to one embodiment of the disclosed invention can provide a plasma variable diagnosis device and method capable of measuring a plasma variable of a constant value regardless of the impedance of the diagnosis circuit by eliminating the voltage division effect of the applied voltage due to the sensing element.

[0009] A plasma variable diagnostic device according to one embodiment of the disclosed invention may include a signal generating unit that generates a voltage, a probe unit that is inserted into the chamber and configured to apply the voltage generated by the signal generating unit to a plasma sheath within the chamber, a sensing element having one end connected to the probe unit so that a current generated from the plasma flows, and a signal transmitting unit that is configured to transmit the voltage generated by the signal generating unit to the probe unit.

[0010] The above signal transmission unit may be composed of an amplifier.

[0011] The signal transmission unit may include a positive input terminal connected to the signal generation unit, a negative input terminal connected to one end of the sensing element, and an output terminal connected to the other end of the sensing element.

[0012] The current generated from the plasma can flow through the sensing element to the output terminal.

[0013] The above plasma variable diagnosis device may further include a sensing unit that measures a current flowing through the sensing element and an analysis unit that calculates the density and electron temperature of the plasma through the measured current.

[0014] The above probe unit may be composed of a probe.

[0015] The plasma variable diagnostic device may further include a blocking capacitor disposed between the probe unit and the sensing element and connected to one end of the sensing element and the signal transmission unit.

[0016] The above blocking capacitor can be configured to have an arbitrary capacitance depending on the frequency of the applied voltage.

[0017] The voltage generated by the above signal generator may be a voltage in the form of an AC sinusoidal wave.

[0018] A plasma variable diagnosis method according to one embodiment of the disclosed invention may include a step of a signal generation unit generating an AC sinusoidal voltage, a step of applying the voltage to a plasma sheath within a chamber through a probe unit, and a step of a sensing unit measuring a current generated from the plasma through a sensing element.

[0019] The step of applying the voltage may include a step of transmitting the voltage to the probe unit by a signal transmitting unit.

[0020] The above signal transmission unit may be composed of an amplifier.

[0021] The signal transmission unit may include a positive input terminal connected to the signal generation unit, a negative input terminal connected to one end of the sensing element, and an output terminal connected to the other end of the sensing element.

[0022] The above plasma variable diagnosis method may further include a step in which the analysis unit calculates the density and electron temperature of the plasma using the current measured by the sensing unit.

[0023] A plasma variable diagnosis device according to one embodiment of the disclosed invention may include a signal generation unit that generates a voltage, a signal transmission unit that is connected to the signal generation unit and configured to transmit the voltage generated from the signal generation unit to plasma, a probe unit that is inserted into the chamber and configured to apply the voltage to a plasma sheath within the chamber, a blocking capacitor that is connected to the probe unit and includes one end to which the voltage is applied, and a sensing element that is connected to the one end of the blocking capacitor so that a current generated from the plasma flows.

[0024] The plasma variable diagnosis device and method according to one embodiment of the disclosed invention has an advantage in that the entire applied voltage can be transmitted to the plasma sheath.

[0025] In addition, the plasma variable diagnosis device and method according to one embodiment of the disclosed invention have the advantage of being able to measure a plasma variable of a constant value regardless of the impedance of the diagnosis circuit by eliminating the voltage division effect of the applied voltage due to the sensing element.

[0026] FIG. 1 is a schematic drawing of a plasma variable diagnosis device and a plasma generation device according to one embodiment of the disclosed invention.

[0027] Fig. 2 is a diagram showing a measurement circuit of a plasma variable diagnosis device according to the prior art.

[0028] FIG. 3 is a diagram showing a plasma variable diagnosis device and a measurement circuit of a plasma generation device according to one embodiment of the disclosed invention.

[0029] Fig. 4 is a drawing showing an equivalent circuit of the measurement circuit of the plasma generating device shown in Figs. 2 and 3, respectively.

[0030] Fig. 5 is a graph showing a pressure distribution according to the voltage applied to the plasma in a plasma variable diagnosis device according to the prior art.

[0031] FIG. 6 is a diagram comparing the sheath voltage applied to the plasma sheath according to the applied voltage in a plasma variable diagnosis device according to the prior art and a plasma variable diagnosis device according to the disclosed invention, and showing the sheath voltage error according to the comparison.

[0032] FIG. 7 is a diagram comparing electron temperatures measured according to applied voltages in a plasma variable diagnosis device according to a prior art and a plasma variable diagnosis device according to the disclosed invention, and illustrating electron temperature errors accordingly.

[0033] FIG. 8 is a diagram comparing the sheath voltage according to the sensing element in a plasma variable diagnosis device according to the prior art and a plasma variable diagnosis device according to the disclosed invention, and showing the sheath voltage error according to the comparison.

[0034] FIG. 9 is a diagram comparing the sheath voltage according to the change of the sensing element in a plasma variable diagnosis device according to the prior art and a plasma variable diagnosis device according to the disclosed invention, and showing the sheath voltage error according to the comparison.

[0035] FIG. 10 is a diagram comparing the sheath voltage according to an increase in plasma density in a plasma variable diagnosis device according to a prior art and a plasma variable diagnosis device according to the disclosed invention, and showing the sheath voltage error according to the comparison.

[0036] FIG. 11 is a diagram comparing electron temperature measurement values ​​according to changes in sensing elements in a plasma variable diagnosis device according to a prior art and a plasma variable diagnosis device according to the disclosed invention, and illustrating electron temperature errors according to the comparison.

[0037] FIG. 12 is a diagram comparing electron temperature measurement values ​​according to an increase in plasma density in a plasma variable diagnosis device according to a prior art and a plasma variable diagnosis device according to the disclosed invention, and showing an electron temperature error according to the comparison.

[0038] FIG. 13 is a flowchart of a plasma variable diagnosis method according to one embodiment of the disclosed invention.

[0039] The embodiments described in this specification and the configurations illustrated in the drawings are merely preferred examples of the disclosed invention, and there may be various modified examples that can replace the embodiments and drawings of this specification at the time of filing of this application.

[0040] Additionally, the same reference numbers or symbols presented in each drawing of this specification represent parts or components that perform substantially the same function.

[0041] Additionally, the terminology used herein is for the purpose of describing embodiments and is not intended to limit and / or restrict the disclosed invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

[0042] In this specification, terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0043] Additionally, terms including ordinal numbers such as “first,” “second,” etc., used herein may be used to describe various components, but the components are not limited by the terms, and the terms are used only for the purpose of distinguishing one component from another.

[0044] For example, without departing from the scope of the present invention, a first component could be referred to as a second component, and similarly, a second component could also be referred to as a first component. The term "and / or" includes any combination of a plurality of related listed items or any one of a plurality of related listed items.

[0045] Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0046] FIG. 1 is a schematic drawing of a plasma variable diagnosis device and a plasma generation device according to one embodiment of the disclosed invention.

[0047] Referring to FIG. 1, a plasma variable diagnosis device (100) according to one embodiment of the disclosed invention may include a plasma generating device (1) that generates plasma, which is a target to be measured, a chamber (10) which is a main body forming a space where plasma is generated, a power source (20) disposed outside the chamber (10), a plurality of antennas (30) disposed on one side of the chamber (10) to generate plasma, an impedance matching unit (40) connected to the antenna (30) to match the impedance of the antenna (30), a substrate (50) on which a plasma process is performed, a plasma variable diagnosis device (100) capable of measuring various variables of plasma within the chamber (10), and a pumping system (60) configured to pump a source gas or the like which is a source of plasma generation.

[0048] More specifically, the chamber (10) can be defined as a container having a space in which a workpiece requiring plasma process treatment, such as a substrate (50), is provided and a space in which plasma is generated.

[0049] As shown in Fig. 1, a plurality of antennas (30) for generating plasma can be installed on the upper part of the chamber (10), and the plurality of antennas (30) can be connected to an impedance matching unit (40).

[0050] The impedance matching unit (40) can be connected to the power source (20) that supplies power (20) to the plasma generating device (1) and the chamber (10), respectively.

[0051] A pumping system for pumping a source gas or the like that serves as a plasma generation source can be formed at the bottom of the chamber (10).

[0052] As shown in Fig. 1, a method of generating plasma using multiple antennas (30) can be referred to as an inductively coupled plasma generating device (1).

[0053] However, the plasma generating device (1) according to the present invention and the plasma variable diagnosis device (100) using the same are not limited to generating plasma using an inductive coupling method, and can be applied to all devices and methods for generating plasma using a capacitive coupling method.

[0054] In the following, for convenience of explanation, the inductively coupled plasma generating device illustrated in Fig. 1 will be used as a reference.

[0055] A plasma variable diagnosis device (100) according to one embodiment of the present invention can measure various state variables of plasma generated inside a chamber (10).

[0056] The state variables used in the present invention refer to variables indicating various chemical and physical characteristics related to plasma.

[0057] For example, as a representative example of a plasma generating device according to the present invention, the plasma generating device can measure the density of plasma inside a chamber (10), the temperature of electrons of plasma inside the chamber (10), and the probability distribution of electron energy.

[0058] For this purpose, a probe (140) of a plasma variable diagnostic device (100) may be provided inside the chamber (10).

[0059] As a representative example, a probe (140) of a plasma variable diagnostic device (100) capable of transmitting a sine wave to the plasma may be placed inside the chamber (10) to penetrate one wall surface of the main body of the plasma generating device (1) forming the chamber (10).

[0060] Accordingly, as illustrated in Fig. 1, when the probe part (140) penetrates one wall surface of the plasma generating device (1) and applies an AC sinusoidal signal to the plasma, the probe part (140) can be said to have the form of a floating probe.

[0061] However, the arrangement of the probe unit (140) is only shown as an example, and the probe unit (140) may be modified and implemented by being provided on the upper part of the pumping system (60).

[0062] The probe (140) is placed inside the chamber (10) and may be composed of a probe including a metal material so that current can flow.

[0063] Through this, when voltage is applied to the probe unit (140) by the voltage generator described later, a current flows in the probe unit (140) due to the potential difference between the plasma and the probe unit (140), and the sensing unit (160) can measure the current flowing through the sensing element (120).

[0064] In addition, the probe (140) according to the disclosed invention can be implemented as a probe having a square shape or a probe having a cylindrical shape.

[0065] However, the embodiment of the present invention is not limited to a square or cylindrical probe, and can be implemented as a probe of various shapes as long as it is a probe capable of measuring the density of plasma or the temperature of electrons.

[0066] In addition, although not shown in the drawing, the control unit can control various components of the plasma generation device (1). Specifically, the control unit can control the power supply (20) that applies voltage to the plasma generation device (1), thereby controlling the size or shape of the voltage applied to the plasma generation device (1), and can control the amount or density of plasma generated by the plasma generation device (1) by adjusting the size of the impedance of the impedance matching unit (40).

[0067] In addition, the control unit can control the voltage generation unit of the plasma variable diagnosis device (100) as well as the plasma generation device (1), and accordingly, can control the size and frequency of the sine wave applied to the probe unit (140).

[0068] Accordingly, the control unit may be implemented as a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA), a programmable logic unit (PLU), a microprocessor, or a device capable of executing and responding to instructions.

[0069] Hereinafter, the measurement circuit of the plasma variable diagnosis device (100) according to the prior art and the plasma variable diagnosis device (100) according to one embodiment of the disclosed invention will be compared and explained.

[0070] Fig. 2 is a diagram showing a measurement circuit of a plasma variable diagnosis device according to the prior art. Fig. 3 is a diagram showing a measurement circuit of a plasma variable diagnosis device and a plasma generation device according to an embodiment of the disclosed invention. Fig. 4 is a diagram showing an equivalent circuit of the measurement circuit of the plasma generation device shown in Figs. 2 and 3, respectively.

[0071] Referring to FIGS. 2 and 3, a plasma variable diagnosis device according to the prior art and a plasma variable diagnosis device (100) according to an embodiment of the disclosed invention may include a measurement circuit used in a floating harmonic analysis method.

[0072] More specifically, the plasma variable diagnosis device according to the prior art and the plasma variable diagnosis device (100) according to an embodiment of the disclosed invention may commonly include a signal application unit (which may be referred to as a signal generation unit) that generates a voltage, a probe unit (140) that is inserted into a chamber (10) and configured to apply the voltage generated by the signal generation unit (110) to a plasma sheath within the chamber (10), a sensing element (120) having one end connected to the probe unit (140) so that a current generated from the plasma flows, and a blocking capacitor (130).

[0073] More specifically, a plasma sheath can represent a specific region occurring in a plasma environment.

[0074] Plasma is a high-energy state of gas composed of electrons and ions, which can be maintained by a reaction process in which electrons collide with ions to create new electrons and ions.

[0075] The plasma sheath refers to the boundary region between the plasma and the surrounding non-plasma environment, where the plasma interacts with its surroundings and exhibits special physical properties.

[0076] The signal generation unit (110) (signal application unit) refers to a configuration that generates a voltage and then applies the generated voltage to the probe unit (140).

[0077] As shown in FIGS. 2 and 3, the signal generation unit (110) (signal application unit) is electrically connected to the probe unit (140), so that a preset voltage can be applied to the probe unit (140) placed inside the chamber (10).

[0078] The shape and size of the voltage applied by the signal generating unit (110) (signal applying unit) to the probe unit (140) may be set differently depending on the plasma generation environment, but a sine wave voltage generated by an AC voltage may be applied.

[0079] Meanwhile, although not shown in FIG. 2, a self-bias generation unit (not shown) may be placed between the probe unit (140) and the signal generation unit (110) (signal application unit). When a sine wave signal generated by the signal generation unit (110) (signal application unit) passes through the self-bias generation unit, a self-bias voltage is applied to both ends of the self-bias generation unit. The self-bias or self-bias voltage value applied to the self-bias generation unit can be measured by the sensing unit (160).

[0080] A blocking capacitor (130) can be used to block DC current generated from plasma.

[0081] In addition, the blocking capacitor (130) can ignore the impedance of the blocking capacitor (130) located inside the circuit by selecting an arbitrary electrostatic capacity according to the frequency of the applied voltage.

[0082] Therefore, the sine wave signal of the plasma is transmitted to the sensing element (120) through the blocking capacitor (130), so that the plasma variable diagnosis device (100) can accurately measure the electrical characteristics of the plasma.

[0083] The sensing element (120) can be configured to allow current generated from the plasma to flow.

[0084] These sensing elements (120) may be composed of one of a resistor, an inductor, and a capacitor.

[0085] More specifically, the sensing element (120) can be connected to a probe portion (140) at one end so that a current generated from the plasma flows.

[0086] A blocking capacitor (130) may be placed between the probe (140) and the sensing element (120).

[0087] The sensing element (120) is connected to the sensing unit (160) at both ends so that the sensing unit (160) can measure the current flowing through the sensing element (120), and the analysis unit (170) can calculate various state variables of the plasma based on the measured current.

[0088] As shown in (a) of FIG. 2 and FIG. 4, the plasma variable diagnosis device according to the prior art has a problem in that since the AC voltage generated from the voltage application unit is applied to the sensing element arranged to measure the high-harmonic current of the plasma, a partial pressure phenomenon occurs in which the AC voltage cannot be applied to the plasma sheath at all.

[0089] Additionally, this pressure gradient phenomenon occurs because as the density of the plasma increases, the impedance of the plasma sheath decreases, resulting in more voltage being applied to the sensing element.

[0090] Therefore, since the harmonic current is dependent on the plasma sheath applied voltage, a very large error occurs in the floating harmonic analysis method that measures plasma variables based on the harmonic current.

[0091] However, as shown in (b) of FIG. 3 and FIG. 4, a plasma variable diagnostic device (100) according to one embodiment of the disclosed invention can provide a measuring circuit that can apply the entire AC voltage to the plasma sheath regardless of the size of the sensing element by using a signal transmission unit (150).

[0092] More specifically, the signal transmission unit (150) may be configured to transmit a voltage generated from the signal generation unit (110) to one end of the sensing element.

[0093] For example, the signal transmission unit (150) may be composed of an amplifier.

[0094] A signal transmission unit (150) composed of an amplifier may include a positive input terminal connected to a signal generation unit (110), a negative input terminal connected to one end of a sensing element (120), and an output terminal connected to the other end of the sensing element (120).

[0095] Accordingly, the AC voltage generated from the signal generator (110) connected to the amplifier is equally transmitted to the positive input terminal and the negative input terminal of the amplifier, and since this is transmitted to one end of the sensing element (120), a decrease in the applied voltage by the sensing element may not occur.

[0096] In addition, since the impedance of the input terminal of the amplifier is configured to be infinite, the current generated from the plasma flows to the output terminal rather than the input terminal of the amplifier, so that plasma current measurement through the sensing element (120) can be possible.

[0097] In addition, in the case of the disclosed invention, even when a deposition film exists in the probe portion (140), there is no need to consider the sensing element (120), so there is a technical effect that the circuit can be applied in a way of measuring the deposition film by implementing an equivalent circuit for the deposition film and plasma sheath.

[0098] In addition, the plasma variable diagnosis device according to the prior art and the plasma variable diagnosis device (100) according to one embodiment of the disclosed invention may commonly include a sensing unit (160) that measures the current of the sensing element (120) and an analysis unit (170) that calculates various state variable values ​​of the plasma by performing a fast Fourier transform (FFT) on the measured current.

[0099] By applying the floating harmonic analysis method to plasma, state variables such as electron temperature, plasma density, and ion flux can be measured using the following equations.

[0100] For example, when the electron distribution has a Maxwellian distribution, the floating potential V f When a small voltage Vo*cos(w*t) is applied to the probe part (140) in , the following bias voltage is applied.

[0101] Equation (1): V B = V f + Vo*cos(w*t)

[0102]

[0103] At this time, the probe (140) current I p can be expressed as a series equation of the harmonic current.

[0104] The kth harmonic current is I kw When this is said, the current of the probe part (140) is as shown in equation (2) below.

[0105] Equation (2):

[0106] Here I k is the kth modified Bessel function of the first kind, and I es , V p , T e represent the electron saturation current, plasma potential, and electron temperature, respectively. Here, the electron temperature can be calculated using the ratio of the first and second harmonic currents as in the following equation (3).

[0107] Equation (3):

[0108] Additionally, the density can be calculated using the electron temperature calculated in equation (3) as shown in equation (4) below.

[0109] Equation (4):

[0110] Here, e is the charge, u B is the Bohm velocity and A p is the area of ​​the probe tip.

[0111] From the above calculated electron temperature and density, the resistance R of the plasma sheath is as follows. sh can be calculated as shown in the following equation (5).

[0112] Equation (5):

[0113] Therefore, as described above, the pressure effect caused by the sensing element (120) can be eliminated through the present invention, thereby enabling accurate plasma variable diagnosis without error.

[0114] Fig. 5 is a graph showing a pressure distribution according to the voltage applied to the plasma in a plasma variable diagnosis device according to the prior art.

[0115] Referring to Fig. 5, the pressure gradient according to the power applied to the inductively coupled plasma can be confirmed.

[0116] Ideally, when voltage V0 is applied to the probe (140), the plasma sheath resistance R formed between the plasma and the probe sh All voltages are applied to obtain a high-harmonic current.

[0117] However, when using a circuit such as (a) of FIG. 2 and FIG. 4, the sensing element (120) R s The voltage is divided, so the desired voltage cannot be applied to the probe.

[0118] The degree to which the voltage V0 applied to the plasma sheath is divided into pressures is called the pressure division R. sh / (R sh +R s ), as shown in Fig. 5, as the applied power increases and the plasma density increases, the sheath resistance decreases and the partial pressure decreases.

[0119] In this case, a very low voltage is applied to the plasma sheath, and also the voltage V applied to the plasma sheath is calculated from the electron temperature and plasma density. sh I don't know.

[0120] Therefore, a large error occurs when measuring the electron temperature from the ratio of the harmonic current.

[0121] FIG. 6 is a diagram comparing the sheath voltage applied to the plasma sheath according to the applied voltage in a plasma variable diagnosis device according to the prior art and a plasma variable diagnosis device according to the disclosed invention, and showing the sheath voltage error according to the comparison.

[0122] Referring to (a) and (b) of FIG. 6, it can be confirmed that the measurement circuit according to the present invention can apply a constant voltage to the plasma sheath regardless of changes in the applied power, compared to the existing measurement circuit.

[0123] On the other hand, in the case of the existing circuit, it can be confirmed that the partial pressure decreases due to the increase in plasma density as the applied power increases and the decrease in plasma sheath resistance caused by it, so that a low voltage is applied to the plasma sheath.

[0124] Accordingly, it can be seen that in the case of existing measurement circuits, as the applied power increases, the error in the sheath voltage increases, causing a serious problem in the reliability of the measurement.

[0125] FIG. 7 is a diagram comparing electron temperatures measured according to applied voltage in a plasma variable diagnosis device according to a prior art and a plasma variable diagnosis device according to the disclosed invention, and showing electron temperature errors accordingly.

[0126] Referring to (a) and (b) of Fig. 7, in the case of the existing circuit, since the voltage change applied to the plasma sheath cannot be considered when measuring the electron temperature, an electron temperature error of 1200% or more is exhibited when the applied power reaches 400 W.

[0127] However, in the case of the measurement circuit of the present invention, since the pressure division phenomenon by the sensing element is eliminated, it can be confirmed that there is no deviation in the measured electron temperature according to the applied power.

[0128] Therefore, the present invention has a technical effect of enabling accurate electronic temperature measurement compared to existing circuits.

[0129] FIG. 8 is a diagram comparing the sheath voltage according to the sensing element in a plasma variable diagnosis device according to the prior art and a plasma variable diagnosis device according to the disclosed invention, and showing the sheath voltage error according to the comparison.

[0130] Referring to (a) and (b) of Fig. 8, the existing circuit has a sensing element R that measures the plasma high-harmonic current. s It can be seen that as the applied voltage increases, the voltage applied to the plasma sheath decreases, and as the applied power increases, the sheath voltage decreases further.

[0131] Accordingly, the shear voltage error in the existing circuit also increases to 90%.

[0132] However, in the case of the measurement circuit of the present invention, it can be confirmed that a voltage can be applied to the plasma sheath at a constant value regardless of changes in the applied power.

[0133] FIG. 9 is a diagram comparing the sheath voltage according to the change of the sensing element in a plasma variable diagnosis device according to the prior art and a plasma variable diagnosis device according to the disclosed invention, and showing the sheath voltage error according to the comparison.

[0134] Referring to (a) and (b) of Fig. 9, the plasma density is 1011 cm -3 , and assuming that the electron temperature is 3 eV and the circuit applied voltage is 2 V, the sheath voltage and sheath voltage error according to the change in the sensing element are shown.

[0135] As shown in Fig. 9, in the case of the existing circuit, if the sensing element (120) is greatly increased, it can be confirmed that the voltage applied to the sensing element (120) increases, and eventually, it becomes impossible to apply the sheath voltage to the measurement circuit.

[0136] FIG. 10 is a diagram comparing the sheath voltage according to an increase in plasma density in a plasma variable diagnosis device according to a prior art and a plasma variable diagnosis device according to the disclosed invention, and showing the sheath voltage error according to the comparison.

[0137] Referring to (a) and (b) of Fig. 10, the sheath voltage and sheath voltage error according to the increase in plasma density are shown assuming that the sensing element is 1000 Ω, the electron temperature is 3 eV, and the circuit applied voltage is 2 V.

[0138] As shown in Fig. 10, it can be confirmed that in the case of the existing circuit, as the plasma density increases, the voltage applied to the plasma sheath decreases, causing a measurement error.

[0139] FIG. 11 is a diagram comparing electron temperature measurement values ​​according to changes in sensing elements in a plasma variable diagnosis device according to a prior art and a plasma variable diagnosis device according to the disclosed invention, and illustrating electron temperature errors according to the comparison.

[0140] Referring to (a) and (b) of Fig. 11, the plasma density is 1011 cm -3 , and assuming that the electron temperature is 3 eV and the circuit applied voltage is 2 V, the electron temperature measurement value and error according to the change in the sensing element are shown.

[0141] As shown in Fig. 11, it can be confirmed that the existing circuit cannot accurately measure the electron temperature because the plasma sheath applied voltage changes depending on the sensing element.

[0142] FIG. 12 is a diagram comparing electron temperature measurement values ​​according to an increase in plasma density in a plasma variable diagnosis device according to a prior art and a plasma variable diagnosis device according to the disclosed invention, and showing an electron temperature error according to the comparison.

[0143] Referring to (a) and (b) of Fig. 12, the electron temperature measurement value and error according to the increase in plasma density are shown assuming that the sensing element is 1000 Ω, the electron temperature is 3 eV, and the circuit applied voltage is 2 V.

[0144] As shown in Fig. 12, the existing circuit changes the pressure gradient due to the change in plasma sheath resistance when the plasma density changes, as well as the change in the sensing element.

[0145] Accordingly, it can be confirmed that it is difficult to accurately measure electron temperature with existing circuits, and it can be confirmed that the circuit of the present invention can measure electron temperature at a constant level even with changes in plasma density.

[0146] FIG. 13 is a flowchart of a plasma variable diagnosis method according to one embodiment of the disclosed invention.

[0147] Referring to FIG. 13, a plasma variable diagnosis method according to one embodiment of the disclosed invention may include a step (S110) in which a signal generation unit generates an AC sinusoidal voltage.

[0148] Thereafter, a plasma variable diagnosis method according to one embodiment of the disclosed invention may include a step (S120) of applying voltage to one end of a blocking capacitor (130) so that the voltage is applied to a plasma sheath within a chamber (10).

[0149] More specifically, the step of applying voltage (S120) may include a step of transmitting the voltage to one end of the blocking capacitor (130) and the probe unit (140) by the signal transmitting unit (150).

[0150] More specifically, the signal transmission unit (150) may be configured as an amplifier.

[0151] For example, the signal transmission unit (150) may be configured as an amplifier including a positive input terminal connected to the signal generation unit (110), a negative input terminal connected to one end of the sensing element (120), and an output terminal connected to the other end of the sensing element (120).

[0152] Thereafter, a plasma variable diagnosis method according to one embodiment of the disclosed invention may include a step (S130) of applying a voltage applied to one end of a blocking capacitor (130) to plasma within a chamber (10) through a probe unit (140).

[0153] Thereafter, a plasma variable diagnosis method according to one embodiment of the disclosed invention may include a step (S140) in which a sensing unit (160) measures a current generated from plasma through a sensing element (120).

[0154] Thereafter, a plasma variable diagnosis method according to one embodiment of the disclosed invention may include a step (S150) of calculating a state variable of the plasma using the measured current.

[0155] Specifically, the step (S150) of calculating the state variable of the plasma using the measured current may include a step in which the analysis unit (170) calculates the density and electron temperature of the plasma using the current measured by the sensing unit (160).

[0156] The plasma variable diagnosis device and method according to one embodiment of the disclosed invention has an advantage in that the entire applied voltage can be transmitted to the plasma sheath.

[0157] In addition, the plasma variable diagnosis device and method according to one embodiment of the disclosed invention have the advantage of being able to measure a plasma variable of a constant value regardless of the magnitude of the applied voltage by eliminating the voltage division effect of the applied voltage due to the sensing element.

[0158] The devices described above may be implemented as hardware components, software components, and / or a combination of hardware components and software components. For example, the devices and components described in the embodiments may be implemented using one or more general-purpose computers or special-purpose computers, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA), a programmable logic unit (PLU), a microprocessor, or any other device capable of executing instructions and responding to them. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. Furthermore, the processing device may access, store, manipulate, process, and generate data in response to the execution of the software. For ease of understanding, the processing device is sometimes described as being used singly; however, those skilled in the art will appreciate that the processing device may include multiple processing elements and / or multiple types of processing elements. For example, the processing device may include multiple processors, or one processor and one controller. Additionally, other processing configurations, such as parallel processors, are also possible.

[0159] Software may include a computer program, code, instructions, or a combination of one or more of these, which may configure a processing device to perform a desired operation or may independently or collectively command the processing device. The software and / or data may be embodied in any type of machine, component, physical device, virtual equipment, computer storage medium, or device for interpretation by the processing device or for providing instructions or data to the processing device. The software may also be distributed over networked computer systems and stored or executed in a distributed manner. The software and data may be stored on one or more computer-readable recording media.

[0160] The method according to the embodiment may be implemented in the form of program commands that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program commands, data files, data structures, etc., alone or in combination. The program commands recorded on the medium may be those specially designed and configured for the embodiment or may be those known and available to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, and hardware devices specially configured to store and execute program commands such as ROMs, RAMs, and flash memories. Examples of program commands include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter, etc.

[0161] Although the embodiments have been described with limited examples and drawings, those skilled in the art will appreciate that various modifications and variations can be made based on the above teachings. For example, appropriate results can be achieved even if the described techniques are performed in a different order than described, and / or components of the described systems, structures, devices, circuits, etc. are combined or combined in a different manner than described, or are replaced or substituted with other components or equivalents. Therefore, other implementations, other embodiments, and equivalents of the claims also fall within the scope of the claims described below.

Claims

1. Signal generation unit that generates voltage; A probe unit inserted into the chamber and configured to apply a voltage generated by the signal generator to a plasma sheath within the chamber; A sensing element having one end connected to the probe so that a current generated from the plasma flows; and characterized in that it includes a signal transmission unit configured to transmit the voltage generated from the signal generation unit to the probe unit; Plasma variable diagnostic device.

2. In paragraph 1, The signal transmission unit is characterized in that it is composed of an amplifier. Plasma variable diagnostic device.

3. In paragraph 2, The signal transmission unit is characterized in that it includes a positive input terminal connected to the signal generation unit, a negative input terminal connected to the one end of the sensing element, and an output terminal connected to the other end of the sensing element. Plasma variable diagnostic device.

4. In paragraph 3, The current generated from the plasma is characterized in that it flows through the sensing element to the output terminal. Plasma variable diagnostic device.

5. In paragraph 1, A sensing unit that measures the current flowing through the sensing element; and It is characterized by further including an analysis unit that calculates the variables of the plasma through the measured current; Plasma variable diagnostic device.

6. In paragraph 1, The above probe part is characterized by being composed of a probe. Plasma variable diagnostic device.

7. In paragraph 1, A blocking capacitor is further included, which is disposed between the probe portion and the sensing element and is connected to one end of the sensing element and the signal transmission portion. Plasma variable diagnostic device.

8. In paragraph 7, The above blocking capacitor is characterized in that it is configured to have an arbitrary electrostatic capacitance depending on the frequency of the applied voltage. Plasma variable diagnostic device.

9. In paragraph 1, The voltage generated by the signal generator is characterized in that it is a voltage in the form of an AC sine wave. Plasma variable diagnostic device.

10. A step in which a signal generation unit generates an AC sine wave voltage; A step of applying the voltage to the plasma sheath within the chamber through the probe; and A sensing unit characterized by including a step of measuring a current generated from the plasma through a sensing element; Method for diagnosing plasma variables.

11. In paragraph 10, The step of applying the above voltage is: characterized in that it comprises a step of transmitting the voltage to the probe unit by a signal transmitting unit; Method for diagnosing plasma variables.

12. In paragraph 11, The signal transmission unit is characterized in that it is composed of an amplifier. Method for diagnosing plasma variables.

13. In paragraph 12, The signal transmission unit is characterized in that it includes a positive input terminal connected to the signal generation unit, a negative input terminal connected to the one end of the sensing element, and an output terminal connected to the other end of the sensing element. Method for diagnosing plasma variables.

14. In paragraph 10, The method further comprises: a step of calculating the density and electron temperature of the plasma using the current measured by the sensing unit; Method for diagnosing plasma variables.

15. Signal generation unit that generates voltage; A signal transmission unit connected to the signal generation unit and configured to transmit a voltage generated from the signal generation unit to plasma; A probe portion inserted into the chamber and configured to apply the voltage to a plasma sheath within the chamber; A blocking capacitor including a terminal connected to the probe section and to which the voltage is applied; and characterized in that it includes a sensing element connected to the one end of the blocking capacitor so that the current generated from the plasma flows; Plasma variable diagnostic device.

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