Residual gas measurement system and method therefor

Abstract

The present invention relates to a residual gas measurement system in a vacuum container, using a chemical reaction calculation model, and a method therefor, and, more specifically, to a residual gas measurement system and a method therefor, in which a calibration parameter for residual gas is calculated using an electron energy density distribution of an ionizer of a quadrupole mass spectrometer and a calibration parameter function calculated using inert gas, and the density of residual gas in a process chamber is measured, on the basis of the chemical reaction calculation model, from a measurement signal of the residual gas received from the quadrupole mass spectrometer.

Description

Residual gas measurement system and method

[0001] The present invention relates to a residual gas measurement system and method in a process chamber using a chemical reaction calculation model, and more specifically, to a residual gas measurement system and method that calculates a calibration parameter for the residual gas using the electron energy density distribution of an ionizer of a quadrupole mass spectrometer and a calibration parameter function calculated using an inert gas, and measures the density of residual gases in the process chamber from a measurement signal of the residual gas received from the quadrupole mass spectrometer based on a chemical reaction calculation model.

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

[0003] The key factors in the semiconductor plasma process are the flux and energy of ions incident on the wafer surface, and the flux of reactive chemical species (radicals) within the vessel. In particular, as reactive chemical species are the agents that trigger the surface chemical reactions required for the process, their density within the vessel is closely related to the wafer surface density.

[0004] Therefore, there is an increasing need for precision measurement technology for each residual gas remaining inside the chamber after the process gas is injected into the vacuum chamber and undergoes various reaction processes.

[0005] Methods for measuring residual gas include plasmafiing the residual gas and analyzing the light emission spectrum, and mass spectrometry involving the extraction of some atoms and molecules from within a vacuum chamber.

[0006] Figure 1 is a configuration diagram of an entire system including a conventional quadrupole mass spectrometry system.

[0007] As illustrated in FIG. 1, the entire system including a conventional quadrupole mass spectrometry system includes a process gas injection unit (10), a process chamber (11), a vacuum pump unit (12) for the process chamber, an orifice (14), a quadrupole mass spectrometry chamber (15), and a vacuum pump unit (16).

[0008] A separate vacuum pump unit (16) is required to maintain a high vacuum in the quadrupole mass spectrometry chamber (15).

[0009] Figure 2 is a diagram illustrating the structure and measurement principle of a general quadrupole mass spectrometer, and Figure 3 is a diagram illustrating the problems when measuring residual gas using a conventional quadrupole mass spectrometer.

[0010] As shown in FIG. 2, atoms / molecules remaining in the vacuum vessel are moved to an ionization device through an orifice. The moved atoms / molecules collide with electrons accelerated by being emitted from a filament and become ionized. The ionized atoms / molecules are transported to a quadrupole mass filter through an ion focuser. Then, only atoms / molecules with specific mass / charge conditions pass through the quadrupole mass filter, collide with a sensor (metal) to be neutralized, and thereby generate an electric current. Then, a value corresponding to the generated current is output. By changing the specific mass / charge conditions of the quadrupole mass filter and measuring the signal, a mass spectrum can be obtained, from which the species of residual gases can be determined.

[0011] However, in the case of molecular gases, there is a problem where measurement precision decreases because not only ionization reactions but also dissociation reactions occur within the ionization device.

[0012] For example, as shown in Fig. 3, the number of oxygen atoms (O) in the chamber is 1, but additional O+ is formed by the dissociative ionization reaction of oxygen molecules (O2), so that the number of O+ ions can be measured as 2.

[0013] In other words, although the number of oxygen atoms in the vacuum vessel is 1, it is measured as 2, so there is a problem with very low precision.

[0014] Korean published patent [10-2021-0062680] discloses a mass spectrometer and a method for analyzing gas by mass spectrometry.

[0015] Korean published patent [10-2021-0068991] discloses a quadrupole mass spectrometer, a quadrupole mass spectrometer method, a program recording medium mass spectrometer on which a program for a quadrupole mass spectrometer is recorded, and a method for analyzing gas by mass spectrometry.

[0016] Korean published patent [10-2023-0042054] discloses a residual gas analyzer and an EUV lithography system having the residual gas analyzer.

[0017] (Patent Document 1) Korean Published Patent [10-2021-0062680] (Publication Date: May 31, 2021)

[0018] (Patent Document 2) Korean Published Patent [10-2021-0068991] (Publication Date: June 10, 2021)

[0019] (Patent Document 3) Korean Published Patent [10-2023-0042054] (Publication Date: March 27, 2023)

[0020] Therefore, the present invention has been devised to solve the problems described above.

[0021] The object of the present invention is to provide a residual gas measurement system and a method for precisely measuring the density of a residual gas in a process chamber from the electron energy density distribution of an ionizer used in a quadrupole mass spectrometer, calibration parameters calculated by applying a calibration parameter function obtained using an inert gas to the residual gas, and a measurement signal of the residual gas of the quadrupole mass spectrometer based on a chemical reaction calculation model.

[0022] The object of the present invention is to provide a quadrupole mass spectrometer for measuring the electron energy density distribution of an ionizer used in a quadrupole mass spectrometer.

[0023] The object of the present invention is to provide a quadrupole mass spectrometer system for obtaining a calibration parameter function using an inert gas.

[0024] 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.

[0025] A residual gas measurement system according to one embodiment of the present invention is based on a chemical reaction calculation model. The residual gas measurement system comprises: a quadrupole mass spectrometer for measuring residual gas in a process chamber; an orifice provided between the process chamber and the quadrupole mass spectrometer for sampling the residual gas; a calibration parameter output unit that outputs a calibration parameter function according to the species of the inert gas using the relationship between the flux of the inert gas and the measurement signal of the quadrupole mass spectrometer; a database in which the electron energy density distribution of the ionizer of the quadrupole mass spectrometer is stored; and a chemical reaction calculation model unit that calculates the density of the residual gas in the process chamber based on the electron energy density distribution received from the database, the measurement signal received from the quadrupole mass spectrometer, the calibration parameter function for the residual gas provided to the calibration parameter output unit, and the chemical reaction calculation model in the process chamber.

[0026] A residual gas measurement method according to one embodiment of the present invention is based on a chemical reaction calculation model. The residual gas measurement method comprises: a database creation step of measuring the electron energy density distribution of an ionizer of a quadrupole mass spectrometer using a Langmuir probe and creating a database; a step of acquiring a measurement signal of a quadrupole mass spectrometer according to pressure for each of the inert gases and calculating a calibration parameter function using the relationship between the flux and the measurement signal; a step of acquiring a measurement signal of residual gases present in a process chamber using a quadrupole mass spectrometer; a step of calculating a calibration parameter according to the mass of the residual gases using the calibration parameter function; and a step of calculating the density of the residual gases in the process chamber based on a chemical reaction calculation model using the electron energy density distribution inside the ionizer provided from the database, the measurement signal of the residual gases received from the quadrupole mass spectrometer, and the calibration parameter of the residual gases.

[0027] A quadrupole mass spectrometer calibration system according to one embodiment of the present invention comprises: a quadrupole mass spectrometer for measuring an inert gas in a chamber; an orifice provided between the chamber and the quadrupole mass spectrometer for sampling the inert gas; and a calibration parameter output unit that outputs a calibration parameter function according to the species of the inert gas using the relationship between the flux of the inert gas and the measurement signal of the quadrupole mass spectrometer.

[0028] In addition, according to one embodiment of the present invention, a computer-readable recording medium is provided that stores a program for implementing a method for measuring residual gas in a vacuum vessel using the chemical reaction calculation model.

[0029] In addition, according to one embodiment of the present invention, a program stored on a computer-readable recording medium is provided to implement a method for measuring residual gas in a vacuum vessel using the chemical reaction calculation model.

[0030] A residual gas measuring system according to one embodiment of the present invention has the effect of being able to precisely measure the density of active atoms, particularly oxygen atoms.

[0031] A residual gas measurement system according to one embodiment of the present invention has the effect of solving the problem of reduced measurement precision caused by the dissociation reaction of molecular gas within an ionization device included in a quadrupole mass spectrometer.

[0032] FIG. 1 is a configuration diagram of an entire system including a conventional quadrupole mass spectrometry system.

[0033] Figure 2 is a diagram illustrating the structure and measurement principle of a general quadrupole mass spectrometer.

[0034] Figure 3 is a diagram illustrating the problems associated with measuring residual gas using a conventional quadrupole mass spectrometer.

[0035] FIG. 4a is a configuration diagram of a residual gas measurement system based on a chemical reaction calculation model according to one embodiment of the present invention.

[0036] FIG. 4b is a diagram illustrating a quadrupole mass spectrometer calibration system according to one embodiment of the present invention.

[0037] FIG. 4c is a diagram illustrating a method for measuring the electron energy density distribution inside a quadrupole mass spectrometer using a Langmuir probe according to one embodiment of the present invention.

[0038] Figure 5 is a diagram illustrating calibration parameters.

[0039] Figure 6 is a diagram illustrating the process of calculating the residual gas density in the process chamber in the chemical reaction calculation model section of Figure 4.

[0040] FIGS. 7 to 10 are drawings for explaining the derivation of formulas for a chemical reaction calculation model, using oxygen atoms and oxygen molecules as examples.

[0041] FIG. 11 is a flowchart of an exemplary embodiment of a method for measuring residual gas in a vacuum vessel using a chemical reaction calculation model according to the present invention.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] In a typical quadrupole mass spectrometer, atoms / molecules within a vacuum vessel are ionized using electron collision reactions and transported to a quadrupole mass filter via an ion focuser; subsequently, only atoms / molecules with specific mass / charge conditions pass through the quadrupole mass filter, collide with a sensor, and then neutralize and output a current value.

[0049] FIG. 4a is a configuration diagram of a residual gas measurement system based on a chemical reaction calculation model according to one embodiment of the present invention.

[0050] Referring to FIG. 4a, a residual gas measurement system (20) according to one embodiment of the present invention includes a process chamber (100), a quadrupole mass spectrometer (200), an orifice (300), a calibration parameter output unit (400), a database (500), and a chemical reaction calculation model unit (600).

[0051] A residual gas measurement system according to one embodiment of the present invention is based on a chemical reaction calculation model. The residual gas measurement system comprises: a quadrupole mass spectrometer (200) for measuring residual gas within a process chamber (100); an orifice (300) provided between the process chamber and the quadrupole mass spectrometer for sampling the residual gas; a calibration parameter output unit (400) that outputs a calibration parameter function according to the species of the inert gas using the relationship between the flux of the inert gas and the measurement signal of the quadrupole mass spectrometer; a database (500) in which the electron energy density distribution of the ionizer of the quadrupole mass spectrometer (200) is stored; and a chemical reaction calculation model unit (600) that calculates the density of the residual gas within the process chamber based on the electron energy density distribution received from the database, the measurement signal received from the quadrupole mass spectrometer, the calibration parameter function for the residual gas provided to the calibration parameter output unit, and the chemical reaction calculation model within the process chamber.

[0052] The process chamber (100) can be any type of chamber capable of performing processes such as etching, deposition, and surface treatment. The chamber can be evacuated by a vacuum pump (109).

[0053] The gas section (106) can inject various process gases and inert gases required for the process into the chamber. In particular, the inert gas can be used to calibrate the quadrupole mass spectrometer (200). The process gas can perform various reactions within the process chamber with the help of heat / plasma, etc. The process chamber can form residual gas derived from the process gas. The residual gas may include the process gas, its decomposed gas, byproduct gas generated by reacting with the workpiece, water vapor and air resulting from leakage, etc. The density of the residual gas may indicate the state of the process chamber (100). Accordingly, in particular, the density of highly active residual gas may be a means of monitoring the process state.

[0054] The pressure sensor (108) can detect the pressure of the process chamber and provide it to the calibration parameter unit. The calibration parameter unit can be used to calibrate the quadrupole mass spectrometer (200).

[0055] The temperature sensor (107) can detect the temperature of the process chamber and provide it to the calibration parameter unit.

[0056] The calibration parameter output unit (400) injects the inert gas into the process chamber (100), receives the pressure of the inert gas and converts it into a flux, receives the measurement signal (S) of the quadrupole mass spectrometer (200), and calculates the calibration parameter function (β) using the relationship between the measurement signal (S) and the flux (Γ) according to the pressure of the inert gas in the process chamber.

[0057] The Singi chemical reaction calculation model unit (600) uses the calibration parameter function (β) according to the mass (M) of the residual gases (X, X2) to calculate the calibration parameter (β). X , β X2 Produces ).

[0058] For example, the Singi chemical reaction calculation model part (600) is the density (n) of the residual gas. X , n X2 ) and the flux (Γ) of the residual gas X , Γ X2 According to the correlation between ), the molecular density of X (n) for any element X contained in the residual gas X2,chem ) and X atomic density (n X,chem ) is calculated using the following [mathematical formula].

[0059] [Mathematical Formula 1]

[0060]

[0061] Here, is the average speed of the X molecule, and is the average speed of the X atom.

[0062] The process chamber (100) may be a space where a semiconductor process is performed in a vacuum and plasma is generated. The process chamber (100) may receive a plurality of process gases from a gas section. The process gases may contain oxygen molecules. The process gases may be dissociated by plasma within the process chamber (100) or react with a substrate to generate various residual gases. The residual gases may include process gases, atoms decomposed from the process gases, and reaction byproduct gases. In particular, since active atoms (active oxygen) decomposed from the process gases (oxygen molecules) have high reactivity, the density of active atoms (active oxygen) can be monitored in real time during the process, and appropriate control necessary for anomaly detection, conditions for operation, endpoint detection, etc., can be performed.

[0063] The above quadrupole mass spectrometer (200) can measure residual gas in the process chamber (100) in real time. The above quadrupole mass spectrometer (200) has a separate vacuum pump built in and can operate at ultra-low pressure.

[0064] The orifice (300) is a passage provided between the process chamber (100) and the quadrupole mass spectrometer (200) to sample residual gas within the process chamber (100).

[0065] The calibration parameter output unit (400) can calculate the calibration parameter function (β) of the quadrupole mass spectrometer (200) using an inert gas. The calibration parameter function (β) may be a calibration parameter based on mass. Accordingly, the calibration parameter can be calculated from the calibration parameter function (β) based on the mass of the residual gas (atoms or molecules) according to the species of the residual gas. The calibration parameter output unit (400) outputs the calibration parameter function (β), and the chemical reaction calculation model unit (600) can calculate the calibration parameter from the calibration parameter function (β) based on the mass of the residual gas (atoms or molecules) using the calibration parameter function (β). Alternatively, the calibration parameter output unit (400) may calculate a calibration parameter from the calibration parameter function (β) according to the mass of the residual gas (atom or molecule) using the calibration parameter function (β) and provide it to the chemical reaction calculation model unit (600).

[0066] The above database (500) stores the electron energy density distribution measured according to the conditions of the ionizer of the quadrupole mass spectrometer (200). The electron energy density distribution is experimentally measured by inserting a Langmuir probe (202) into the ionization device. The above database (500) may be a non-volatile memory. The electron energy density distribution of the above database (500) may be stored after being measured experimentally in advance.

[0067] The chemical reaction calculation model unit (600) receives the electron energy density distribution from the database (500) and the measurement signal (S) of the residual gas (X) received from the quadrupole mass spectrometer (200). X ), calibration parameter (β) calculated in response to the above residual gas X ), using a chemical reaction calculation model (0D global model), the density of residual gas (n) in the process chamber (100) X ) can be calculated in real time. The chemical reaction calculation model unit (600) can be performed by a computer. The chemical reaction calculation model (0D global model) can be based on particle balance equations.

[0068] The above process chamber may use a single gas, a mixed gas, or plasma. For semiconductor plasma processes, various process parameters such as RF power, RF frequency, pulse frequency, and pulse duty ratio may be used.

[0069] FIG. 4b is a diagram illustrating a quadrupole mass spectrometer calibration system according to one embodiment of the present invention.

[0070] FIG. 4b shows a quadrupole mass spectrometer calibration system (40) according to one embodiment of the present invention, comprising: a quadrupole mass spectrometer (200) for measuring an inert gas in a chamber (100); an orifice (300) provided between the chamber (100) and the quadrupole mass spectrometer (200) for sampling the inert gas; and a calibration parameter output unit (400) that outputs a calibration parameter function (β) according to the species of the inert gas using the relationship between the flux (Γ) of the inert gas and the measurement signal (S) of the quadrupole mass spectrometer.

[0071] The calibration parameter output unit (400) receives the pressure of the chamber and converts it into a flux (Γ), receives the measurement signal (S) of the quadrupole mass spectrometer, and can calculate a calibration parameter function (β) using the relationship between the measurement signal (S) and the flux (Γ) according to the pressure of the inert gas of the chamber.

[0072] The pressure sensor (108) can detect the pressure of the chamber (100) and provide it to the calibration parameter unit (400). The calibration parameter unit (400) can be used to calibrate the quadrupole mass spectrometer (200).

[0073] The temperature sensor (107) can detect the temperature of the chamber (100) and provide it to the calibration parameter unit.

[0074] The gas section (106a) can supply an inert gas to the chamber. The inert gas may include at least two of He, Ne, Ar, Kr, and Xe. Preferably, the inert gas may include all of He, Ne, Ar, Kr, and Xe.

[0075] Figure 5 is a diagram illustrating calibration parameters.

[0076] Referring to FIG. 5, in a quadrupole mass spectrometer, atoms / molecules in the quadrupole chamber are ionized using an electron collision reaction and transported to a quadrupole mass filter through an ion focuser, and then only atoms / molecules with specific mass / charge conditions pass through the quadrupole mass filter and collide with a sensor unit, after which neutralization and current values ​​are output.

[0077] Correction parameter (β) for an arbitrary gas X x Set ) (S501). Calibration parameter (β x ) is the probability (T) that X passes through the ion focuser and quadrupole mass filter. op-quad,X It is a function of ), T op-quad,XIt depends on the mass of the gas.

[0078] The above calibration parameters and It is expressed by the following [Mathematical Formula 2].

[0079] [Mathematical Formula 2]

[0080]

[0081]

[0082] Here, is a calibration parameter for the X numerator, and is a calibration parameter for the X atom, and A opitcs T is the area of ​​the hole in the ion focuser, and V is the volume of the ion focuser. op-quad,X2+ is the probability that a molecule X passes through an ion focuser and a quadrupole mass filter, and T op-quad,X+ is the probability that an X atom passes through an ion focuser and a quadrupole mass filter.

[0083] To obtain calibration parameters, one of the inert gases (He, Ne, Ar, Kr, Xe) is selected (S501a). For example, argon gas (Ar) is injected, and the pressure (P) is measured using a vacuum gauge inside the process chamber (S501b).

[0084] Using the above pressure, the flux (Γ) of argon gas entering from the process chamber through the orifice Ar,cham Calculate )(501c).

[0085] And, the measurement signal of the quadrupole mass spectrometer (S Ar+ Measures ).

[0086] And, the flux of argon gas (Γ Ar,cham ) and calibration parameters (β Ar+ Plot the graph of the variable excluding ) (S502).

[0087] By varying the argon gas inflow and changing the pressure, the measurement signal (S) of the quadrupole mass spectrometer is obtained within a sufficient pressure range.Ar+ Measures and calculates ).

[0088] When the pressure scan is complete, the calibration parameter (β) is derived from the slope of the graph using the following [mathematical formula]. Ar+ Produces ).

[0089] [Mathematical Formula 3]

[0090]

[0091] Here, since argon is an inert gas, the orifice permeability (T ori,A r) is 1 and the pumping speed (L) of the pump pump ) is determined by the pump specifications. By measuring the orifice diameter, the orifice area (A ori Calculate the ionization reaction rate (K) using the electron energy density distribution function measured by inserting a probe into the ionization device. iz) and electron density (n e Calculate )

[0092] The process of calculating calibration parameters after changing the inert gas (Ar) to another inert gas (Ne) is repeated (S502a, S502b). When calibration parameters have been obtained for all inert gases, the calibration parameter output unit (400) obtains a calibration parameter function using the calibration parameters according to the mass of the inert gas (S504).

[0093] In the above calibration parameter output unit (400), a calibration parameter function (β(m)) (504) according to mass (m) can be obtained through experiments with other inert gases, such as argon gas (S504).

[0094] In the calibration parameter output unit (400) above, when the mass of the residual gas (X) is determined, the calibration parameter (β) corresponding to the determined mass X ) can be determined (S505).

[0095] FIG. 4c is a diagram illustrating a method for measuring the electron energy density distribution inside a quadrupole mass spectrometer using a Langmuir probe according to one embodiment of the present invention.

[0096] Referring to FIG. 4c, the quadrupole mass spectrometer (30) ionizes atoms / molecules in the quadrupole chamber using an electron collision reaction, transports them to a quadrupole mass filter through an ion collector, and then only atoms / molecules with specific mass / charge conditions pass through the quadrupole mass filter and collide with the sensor unit, and then neutralizes and outputs a current value.

[0097] A quadrupole mass spectrometer (30) according to one embodiment of the present invention includes an ionization device that accelerates electrons by emitting them. The ionization device includes a Langmuir probe (202) that measures electrons accelerated in an ultra-vacuum state. The Langmuir probe measures the current according to the applied voltage to measure the ion energy density distribution. The ion energy density distribution is stored in a data analyzer (500). The ion energy density distribution may be provided to a calibration parameter output unit (400) and a chemical reaction calculation model unit (600).

[0098] Figure 6 is a diagram illustrating the process of calculating the residual gas density in the process chamber in the chemical reaction calculation model section of Figure 4a.

[0099] Hereinafter, any element X included in the gas entering the quadrupole mass spectrometer (200) from the process chamber (100) through the orifice (300) will be described as an example.

[0100] As illustrated in FIG. 6, the chemical reaction calculation model unit (600) receives an electron energy density distribution from the database (400) and a measurement signal (S) from the quadrupole mass spectrometer (200). X2+ ,S X+ ) is received, and the calibration parameter from the calibration parameter output unit (400) and Receives.

[0101] The electron energy density distribution received from the above database (500) is fe(v), and the measurement signal S received from the above quadrupole mass spectrometer (200) X+ and S X2 It is expressed by the following [Mathematical Formula 4].

[0102] [Mathematical Formula 4]

[0103]

[0104] Here, S X2+ is the current value measured by a quadrupole mass spectrometer for the molecule X, and, and S X+ is the current value measured by the quadrupole mass spectrometer for atom X, and Γ X2+ is the flux of X molecular ions incident from the ionization device to the ion focuser, and Γ X+ is the flux of X atomic ions incident from the ionization device to the ion focuser, and T op-quad,X2+ is the probability that a molecule X passes through an ion focuser and a quadrupole mass filter, and T op-quad,X+ is the probability that an X atom passes through an ion focuser and a quadrupole mass filter, and A sen is the sensor area of ​​the quadrupole mass spectrometer.

[0105] The calibration parameters output above and It is expressed by the following [Mathematical Formula 2].

[0106] The flux (Γ) of the above arbitrary element X molecule derived using particle balance equations X2,chem ) and the flux (Γ of an atom of any element X X,chem ) is calculated using the following [Equation 5].

[0107] [Mathematical Formula 5]

[0108]

[0109] Here, Kiz,X is the electron collision ionization reaction rate of atom X. K iz,X2 is the electron collision ionization reaction rate of molecule X. K dis is the electron collision dissociation reaction rate of molecule X. K dis,iz n is the electron collision dissociation ionization reaction rate of molecule X. e is the electron density within the ionization device.

[0110] [Mathematical Formula 6]

[0111]

[0112] Here, v is the electron velocity, and σ iz,X (v) is the collision cross-section of the ionization reaction of atom X. σ iz,X2 (v) is the ionization reaction collision cross-section of molecule X. σ dis (v) is the collision cross-section of the dissociation reaction of molecule X. σ dis,iz (v) is the collision cross-section of the dissociative ionization reaction of molecule X. T ori,X2 is the probability of X molecule passing through the orifice. T ori,X is the probability of an atom passing through the orifice. A ori is the hole area of ​​the orifice.

[0113] Subsequently, according to the correlation between density and flux, the molecular density of X (Γ for the arbitrary element X) X.cham ) and X atomic density (n X,cham ) is calculated using [Mathematical Formula 1].

[0114] Although the above description used the case of a single gas X as an example, the present invention is not limited thereto, and in the case of a mixed gas, it is also possible to measure the density of the residual gas by using all particle conservation equations that can be formed depending on the type and ratio of the gas.

[0115] Next, we will explain in more detail the method for calculating residual gas density derived from particle balance equations.

[0116] Below, we will examine the method for measuring residual gases of oxygen atoms and oxygen molecules.

[0117] Figures 7 to 10 are diagrams illustrating the derivation of formulas for a chemical reaction calculation model using oxygen atoms and oxygen molecules as examples.

[0118] As shown in FIG. 7, particle balance equations for oxygen atoms and oxygen molecules can be expressed as equations (1) to (4).

[0119] Subsequently, as shown in FIG. 8, equation (4) is n O2 By summarizing the equations for the measurement signal and calibration parameters of the quadrupole mass spectrometer, it can be expressed as in equation (5).

[0120] Also, equation (3) n O By summarizing the equations for the measurement signal and calibration parameters of the quadrupole mass spectrometer, it can be expressed as equation (6).

[0121] Subsequently, as shown in FIG. 9, in (1) form, Γ O2,cham To summarize regarding this, it is expressed as in (7), and in equation (2), Γ O,cham To summarize, it is expressed as in (8).

[0122] Afterwards, as shown in Fig. 10, if equation (5) is substituted into equation (7) and simplified, it can be expressed as equation (9), and if equations (5) and (6) are substituted into equation (8) and simplified, it can be expressed as equation (10).

[0123] Based on the correlation between density and flux, finally, the density of oxygen molecules (n) inside the chamber O2,cham ) is expressed as in equation (11), and the density of oxygen atoms in the chamber (n O,cham ) is expressed as in equation (12).

[0124] FIG. 11 is a flowchart of an exemplary embodiment of a method for measuring residual gas in a vacuum vessel using a chemical reaction calculation model according to the present invention.

[0125] Referring to FIG. 11, a residual gas measurement method based on a chemical reaction calculation model comprises: a database creation step (S10) of measuring the electron energy density distribution of an ionizer of a quadrupole mass spectrometer using a Langmuir probe and creating a database; a step (S20) of acquiring a measurement signal of a quadrupole mass spectrometer according to pressure for each of the inert gases and calculating a calibration parameter function using the relationship between the flux and the measurement signal; a step (S30) of acquiring a measurement signal of residual gases present in a process chamber using a quadrupole mass spectrometer; a step (S40) of calculating a calibration parameter according to the mass of the residual gases using the calibration parameter function; and a step (S50) of calculating the density of each of the residual gases in the process chamber based on a chemical reaction calculation model using the electron energy density distribution inside the ionizer provided from the database, the measurement signal of the residual gases received from the quadrupole mass spectrometer, and the calibration parameter of the residual gases.

[0126] According to the correlation between the density of the residual gas and the flux (Γ) of the residual gas, the molecular density of X (n) for any element X X2,chem ) and X atomic density (n X,chem ) is calculated using the following [Mathematical Formula 1].

[0127] [Mathematical Formula 1]

[0128]

[0129] Here, is the average speed of the X molecule, and is the average speed of the X atom.

[0130] The above residual gas may include at least one of oxygen atoms, oxygen molecules, fluorine atoms, chlorine atoms, and water vapor.

[0131] The above inert gas may include at least two of He, Ne, Ar, Kr, and Xe.

[0132] First, the electron energy density distribution according to the conditions of the quadrupole mass spectrometer is measured and stored in a database (S10).

[0133] Afterwards, a calibration parameter function for the measurement signal of the quadrupole mass spectrometer is calculated using an inert gas (S20).

[0134] Afterwards, the residual gas in the process chamber is measured using the quadrupole mass spectrometer (S30).

[0135] Afterwards, a calibration parameter according to the mass of any element included in the gas is calculated and output from the calibration parameter function calculated in the calibration parameter function calculation step (S20) (S40).

[0136] Subsequently, the residual gas density in the process chamber is calculated using the electron energy density distribution received from the database according to the conditions of the process chamber, the measurement signal received from the quadrupole mass spectrometer, and a chemical reaction calculation model based on the calibration parameters (S50).

[0137] The above gas density calculation step (S50) calculates the residual gas density in the chamber according to the description in FIG. 6.

[0138] Although a method for measuring residual gas in a vacuum vessel using a chemical reaction calculation model 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 method for measuring residual gas in a vacuum vessel using a chemical reaction calculation model, and a program stored on the computer-readable recording medium for implementing the method for measuring residual gas in a vacuum vessel using a chemical reaction calculation model, can also be implemented.

[0139] That is, those skilled in the art will readily understand that the method for measuring residual gas in a vacuum vessel using the chemical reaction calculation model described above may be provided by being included in a computer-readable recording medium by tangibly implementing a program of instructions for implementing it. 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.

[0140] 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 residual gas measurement system based on a chemical reaction calculation model, Quadrupole mass spectrometer for measuring residual gas in a process chamber; An orifice provided between the process chamber and the quadrupole mass spectrometer to sample the residual gas; A calibration parameter output unit that outputs a calibration parameter function according to the species of inert gas using the relationship between the flux of the inert gas and the measurement signal of the quadrupole mass spectrometer; A database in which the electron energy density distribution of the ionizer of the above quadrupole mass spectrometer is stored; and A residual gas measurement system characterized by comprising: a chemical reaction calculation model unit that calculates the density of residual gas in the process chamber based on an electron energy density distribution received from the above database, a measurement signal received from the above quadrupole mass spectrometer, a calibration parameter function for the residual gas provided to the above calibration parameter output unit, and a chemical reaction calculation model in the process chamber.

2. In Paragraph 1, A residual gas measurement system characterized by the above calibration parameter output unit injecting the inert gas into the process chamber, receiving the pressure of the inert gas and converting it into a flux, receiving the measurement signal of the quadrupole mass spectrometer, and calculating the calibration parameter function using the relationship between the measurement signal and the flux according to the pressure of the inert gas in the process chamber.

3. In Paragraph 2, A residual gas measurement system characterized by the chemical reaction calculation model unit calculating the calibration parameter according to the mass of the residual gases using the calibration parameter function.

4. In Paragraph 1, According to the correlation between the density (n) of the residual gas and the flux (Γ) of the residual gas, the molecular density (n) of X for any element X X2 ) and X atomic density (n X A residual gas measurement system characterized by being calculated using the following [mathematical formula]. [Mathematical Formula] Here, is the average speed of the X molecule, and is the average speed of the X atom.

5. In a residual gas measurement method based on a chemical reaction calculation model, A database creation step of measuring the electron energy density distribution of the ionizer of a quadrupole mass spectrometer using a Langmuir probe and creating a database; A step of acquiring a measurement signal from a quadrupole mass spectrometer according to pressure for each of the inert gases and calculating a calibration parameter function using the relationship between the flux and the measurement signal; A step of acquiring measurement signals of residual gases present in the process chamber using a quadrupole mass spectrometer; A step of calculating a calibration parameter according to the mass of the residual gases using a calibration parameter function; and A method for measuring residual gases, characterized by including the step of calculating the density of each residual gas in the process chamber based on a chemical reaction calculation model using the electron energy density distribution inside the ionizer provided from the database, the measurement signal of the residual gases received from the quadrupole mass spectrometer, and the calibration parameter of the residual gases.

6. In Paragraph 5, According to the correlation between the density (n) of the residual gas and the flux (Γ) of the residual gas, the molecular density (n) of X for any element X X2 ) and X atomic density (n x A residual gas measurement method characterized by being calculated using the following [mathematical formula]. [Mathematical Formula] Here, is the average speed of the X molecule, and is the average speed of the X atom.

7. In Paragraph 5, A method for measuring residual gas characterized in that the above residual gas comprises at least one of oxygen atoms, oxygen molecules, fluorine atoms, chlorine atoms, and water vapor.

8. In Paragraph 1, A method for measuring residual gas characterized in that the above-mentioned inert gas comprises at least two of He, Ne, Ar, Kr, and Xe.

9. Quadrupole mass spectrometer for measuring inert gas in a chamber; An orifice provided between the chamber and the quadrupole mass spectrometer for sampling the inert gas; and A quadrupole mass spectrometer calibration system comprising: a calibration parameter output unit that outputs a calibration parameter function according to the species of inert gas using the relationship between the flux of the inert gas and the measurement signal of the quadrupole mass spectrometer.

10. In Paragraph 9, A quadrupole mass spectrometer calibration system characterized by the above calibration parameter output unit receiving the pressure of the chamber and converting it into a flux, receiving the measurement signal of the quadrupole mass spectrometer, and calculating a calibration parameter using the relationship between the measurement signal and the flux according to the pressure of the inert gas of the chamber.

11. In a quadrupole mass spectrometer comprising an ionization device that accelerates by emitting electrons, The above ionization device includes a Langmuir probe that measures electrons accelerated in an extreme vacuum state, and The above Langmuir probe measures the ion energy density distribution by measuring the current according to the applied voltage, and A quadrupole mass spectrometer characterized by the above-mentioned ion energy density distribution being stored in a data analyzer.

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