TWM592512U - Gas analysis apparatus - Google Patents

Abstract

The present invention proposes an apparatus for analyzing gas acoustically. The apparatus comprises a controller, a gas analyzer and a detector. The control element is for controlling the action of the gas analyzer. The gas analyzer is comprised of a sealed chamber for gases, a transmitter and a receiver. The transmitter and the receiver are for exciting and receiving an acoustic energy of the gas by using a broadband signal. The detector is for determining the speed of sound by measuring the resonant frequency, and further calculating the properties and composition of gases. By using acoustic impedance materials and high-quality factor resonator, the resolution and accuracy of the apparatus will be enhanced. The apparatus can be applied to the precursor concentration monitor in chemical vapor deposition.

Description

Gas analysis device

The present invention relates to a gas analysis device, and more particularly to an acoustic resonance frequency method using an electroacoustic transducer with acoustic impedance materials and a high quality factor resonance cavity to enhance the stability and sensitivity of the resulting sound velocity It can further accurately analyze the nature and composition of the gas.

The chemical vapor deposition process is widely used to grow various high-purity films such as metals, semiconductors, and dielectrics. A typical chemical vapor deposition process usually exposes the substrate to one or more metal organic ligands or volatile polymers. These complex molecules are often referred to as precursors, and the gas phase precursors are transported to the surface of the substrate through the carrier gas Chemical reactions occur to produce deposits of uniform thickness and quality. The thickness and quality of the film can be achieved by adjusting the concentration of the mixed gas, so it is necessary to accurately measure the molar fraction of the precursor and carrier gas. The gas analysis device can be used not only for monitoring the concentration of precursors in the chemical vapor deposition process, but also for the process safety system to measure the gas concentration around the environment and the feed inspection of quality management to confirm the required concentration of the gas source.

distance between transmitter and receiver/time of flight)。該聲音脈衝之工作頻率通常於超聲波範圍(>0.1MHz)。使用飛行時間法常見的問題包含迴音、訊號衰減和脈衝形狀失真等。 The analysis principles of current commercial gas analysis devices are mostly based on optical methods, acoustic methods, gas chromatographs, mass spectrometers, and calorimetry methods. Among them, acoustic methods can be subdivided into time of flight and resonance frequency. The time-of-flight method is to use a sending electroacoustic transducer to send a sound pulse, and later to receive the sound pulse by another receiving electroacoustic transducer, by measuring the flight time of the sound pulse at a fixed distance to calculate the speed of sound, The sound speed is proportional to the relationship between the time of flight divided by the distance between the sending electroacoustic transducer and the receiving electroacoustic transducer (sound speed

distance between transmitter and receiver/time of flight). The working frequency of the sound pulse is usually in the ultrasonic range (>0.1MHz). Common problems with the time-of-flight method include echo, signal attenuation, and pulse shape distortion.

distance between transmitter and receiver × resonant frequency)。目前市面上使用共振頻率法之氣體分析儀常見的問題有：電聲換能器的固有頻率與氣體的固有頻率相近而互相干擾共振、共振腔室尺寸過小無法提供高品質因子的環境、電聲換能器置於共振腔室之外側而無法承受共振腔室內外的壓力差、共振腔室內材料之聲學阻抗不匹配而導致能量損耗、受流量干擾以致共振腔室內氣體溫度不易控制、共振腔室內壓力影響電聲換能器頻率測量的精度等。 此外，常見的氣體分析裝置通常假定共振腔室內氣體為理想氣體，無測量即時溫度與壓力等參數以修正體積與熱動力學係數，進而修正共振頻率及聲速，並且須依據定期參考氣體所測得的校正數值以計算相對濃度。 Another method for measuring the speed of sound is the resonance frequency method. When the frequency of the applied sound wave is close to the natural frequency of the material to be measured, the material to be tested will generate a standing wave with a larger sound wave amplitude and a different period. This phenomenon is resonance. The applied sound wave frequency will have different specific frequency response values due to the natural frequencies of different substances to be measured, and this specific frequency is the resonance frequency. The resonance frequency method is used for the gas in the closed cavity, plus a specific frequency range of sound frequency to resonate the natural frequency of the gas in the cavity. The sound velocity is calculated by measuring the resonance frequency of the gas, which is proportional to the resonance frequency and the transmitter The relationship between the distance product and the receiver (sound speed

distance between transmitter and receiver × resonant frequency). At present, the common problems of gas analyzers using the resonance frequency method on the market are: the natural frequency of the electroacoustic transducer is close to the natural frequency of the gas and interferes with each other. The resonance chamber is too small to provide a high quality factor environment. The transducer is placed outside the resonance chamber and cannot withstand the pressure difference between the inside and outside of the resonance chamber, the acoustic impedance of the materials in the resonance chamber does not match, which results in energy loss, and the flow is disturbed so that the temperature of the gas in the resonance chamber is not easy to control. Pressure affects the accuracy of frequency measurement of electroacoustic transducers. In addition, common gas analysis devices usually assume that the gas in the resonance chamber is an ideal gas, without measuring real-time temperature and pressure parameters to modify the volume and thermodynamic coefficients, and then correct the resonance frequency and sound velocity, and must be measured based on the periodic reference gas To calculate the relative concentration.

In summary of the above problems, the current analyzer using the resonance frequency method is not only low in reproducibility, resolution, and accuracy, but also limited in the operable operating frequency range is too narrow and can only be applied to dozens of gases.

In order to improve the above deficiencies, the new gas analysis device uses a resonance frequency method under acoustic impedance materials, and uses a larger size resonance chamber (>100cm ³ ) to provide a high quality factor resonance chamber to improve measurement Signal-to-noise ratio, and the electroacoustic transducer is installed in the chamber so that both sides of the transducer are subjected to the same pressure to eliminate the damage caused by overpressure or rapid decompression, thus allowing high flow and high pressure gas to enter the chamber The new type uses the measurement results of pressure and temperature to correct the effect of electroacoustic transducer on the resonance frequency, as well as the specific heat of the real gas, virial correction, gas thermal viscosity correction and gas The effect of relaxation correction on the resonance frequency and sound velocity can further improve the stability and accuracy of frequency measurement and gas concentration analysis, and can analyze and measure the properties and composition of tens of thousands of gases.

To achieve one of the objectives of the new model, the present invention provides a gas analysis device, including: a control element, a gas analyzer, and a measuring element, the control element generates a broadband signal, and is used to control the gas analyzer Acting; the gas analyzer mainly includes: a closed chamber for containing a gas, the closed chamber is provided with a sending end, a receiving end, a gas inlet and a gas outlet, and the closed chamber is provided with an acoustic impedance Material layer; a transmitting element, arranged at the transmitting end, for exciting the resonance energy (frequency) of the gas with a first broadband signal; a receiving element, arranged at the receiving end, for receiving the resonance energy (frequency) of the gas ) Convert the second broadband signal; and a measuring element, calculate the resonance energy (frequency) of the gas according to the second broadband signal, and according to the fixed distance between the transmitting end and the receiving end of the enclosed chamber and the The resonance frequency of a gas calculates the sound velocity of the gas, which in turn determines the nature and composition of the gas.

According to one of the features of the present invention, the acoustic impedance material layer is a discontinuous corner where at least one thin film layer is applied to the inner wall of the enclosed chamber, and is selected from materials with low acoustic impedance coefficients to avoid energy loss and interference with gas resonance caused by scattering of acoustic waves at the corner Frequency, common low acoustic impedance materials can be selected from polyimide (Polyimide) film, fluoropolymer (Fluoropolymer), epoxy (Epoxy), polyurethane (Polyurethane).

According to one feature of the present invention, the volume of the closed chamber is greater than 100 cm ³ or more, so as to provide a resonance effect with a high quality factor.

According to one feature of the present invention, the transmitting element and the receiving element are disposed inside the closed chamber.

According to one feature of the present invention, the transmitting element includes a first broadband electro-acoustic transducer to convert an electrical energy signal into an acoustic signal; the receiving element includes a second broadband electro-acoustic transducer to convert an acoustic signal into a Energy signal.

According to one feature of the present invention, the transmitting element and the receiving element include a conversion layer, which is composed of a single layer or multiple layers of acoustic impedance matching material films, so that the acoustic impedance of the broadband electroacoustic transducer is matched to the gas. The acoustic impedance material includes a metal thin film and/or a non-metallic thin film, the metal thin film is in contact with the broadband electroacoustic transducer, and the metal thin film material is selected from gold, silver, copper, iron, titanium, aluminum, chromium, tungsten, Tin, zirconium, molybdenum, nickel, and the non-metallic film is between the metal film and the gas, and has chemical resistance, the non-metallic film material is selected from polyimide (Polyimide), fluorine-containing polymer (Fluoropolymer), epoxy (Epoxy), polyester (Polyester) and polyurethane (Polyurethane).

According to one feature of the present invention, the transmitting element further includes a protective case, so that the acoustic impedance of the wide-band electroacoustic transducer does not match the closed chamber, but matches the acoustic impedance of the gas. The broadband transducer is arranged inside the protective shell.

According to one feature of the present invention, the broadband electroacoustic transducer can be selected from an electric transducer, an electromagnetic transducer, an electrostatic transducer, or a piezoelectric transducer.

According to one feature of the present invention, the frequency range of the broadband signal is between 0 and 1 MHz, preferably between 0-36 KHz.

According to one feature of the present invention, the gas analysis device includes several heating elements for heating the gas analysis device to degas the gas analyzer, reducing background error interference during measurement.

According to one feature of the present invention, the gas analysis device includes a plurality of temperature sensing elements. The temperature sensing element is disposed inside the enclosed chamber or in the gas inlet and outlet pipes, close to the enclosed chamber, to accurately measure the gas temperature.

According to one feature of the present invention, the gas analysis device includes a pressure sensing element that is disposed inside the enclosed chamber or in the gas inlet and outlet pipelines, close to the enclosed chamber, to accurately measure the gas pressure.

According to one feature of the present invention, the gas analysis device is configured to be used in a reactor using a chemical vapor deposition process, and the determined resonance frequency can sink the composition of the gas used in the reactor.

According to one feature of the new type, the measuring element is based on digital signal processing (Digital The Fast Fourier Transform (FFT) model of Signal Processing (DSP) converts the received acoustic energy of the gas into a sound spectrum, from 0 to 1 MHz, with a real-time correlation analysis (Real-time correlation analysis) ) Determine the resonance frequency of the gas.

According to one feature of the new type, the measuring element is based on a Lorentzian fit (Lorentzian fitting), used to correspond to the acoustic spectrum of the acoustic energy of the gas received, to obtain a fine resolution of the resonance frequency of the gas.

In order to accurately analyze the nature and composition of the gas, the gas analyzer is provided with a temperature sensor element to measure the true temperature of the gas, and a pressure sensing element to measure the true pressure of the gas. The actual temperature value and the actual pressure value are used to correct the heat capacity ratio of the real gas and the acoustic virial correction of the speed of sound. At the same time, the resonance frequency deviation of the electroacoustic transducer caused by the gas pressure fluctuation is also corrected. And through the thermodynamic data of the gas in the gas analysis device, the effects such as gas viscosity and relaxation phenomena on the resonance frequency and sound velocity are corrected. Therefore, the true sound velocity and properties of the gas can be accurately calculated according to the measurement of the true temperature and true pressure, and then the composition of the gas can be accurately analyzed.

These and other features and advantages will be apparent from the following detailed description that should be read in conjunction with the accompanying drawings.

10: Gas analysis device

90: control element

100: gas analyzer

110: closed chamber

112: sender

114: receiver

116: Gas inlet

118: gas outlet

130: sending element

132: Transmitting element protective shell

140: receiving element

142: Receiver component protective shell

150: measuring element

160: Acoustic impedance material layer

170: temperature sensing element

210: the first broadband transducer

212: first substrate layer

214: Printed coil circuit

230: Strong magnet

235: Strong magnetic field

250: the first conversion layer

252: First metal film

254: The first non-metallic film

310: Second broadband transducer

312: Second substrate layer

314: Printed coil circuit

330: Strong magnet

335: Strong magnetic field

350: second conversion layer

352: Second metal film

354: Second non-metallic film

Although the present invention can be expressed in different forms of embodiments, the figures shown and described below are preferred embodiments of the new type, and please understand that the present disclosure is considered as an example of the new type , And is not intended to limit the invention to the specific embodiments shown and/or described.

Fig. 1 shows an exploded schematic view of an embodiment of a gas analysis device according to the present invention.

FIG. 2 shows a detailed schematic diagram of the transmitting element 130 and a detailed schematic diagram of the receiving element 140 according to the embodiment of the gas analysis device of the present invention.

Fig. 3 shows a flowchart of an embodiment of the gas analysis method according to the present invention.

Fig. 4 shows a detailed flowchart of step 7 of the gas analysis method according to the present invention.

Fig. 5 shows a schematic diagram of the acoustic resonance frequency of the gas analyzed in the gas analysis device of the present invention, where (a) the acoustic impedance material layer or high-quality factor resonance chamber of the present invention is not used; (b) the new model is used The acoustic impedance material layer or high quality factor resonance chamber.

In order to make the purpose, features and advantages of the present invention more obvious and understandable, a few preferred embodiments are described below in conjunction with the accompanying drawings, which are described in detail below.

Please refer to FIG. 1, which is an exploded schematic view of the structure of an embodiment of the gas analyzer 10 according to the present invention. The gas analysis device 10 mainly includes a control element 90, a gas analyzer 100 and a measurement element 150. The gas analyzer 100 mainly includes: a closed chamber 110, a transmitting element 130 and a receiving element 140. The closed chamber 110 is used for containing gas. The closed chamber 110 is provided with a sending end 112, a receiving end 114, a gas inlet 116 and a gas outlet 118; Inflow and outflow from the gas outlet 118, and an acoustic impedance material layer 160 is provided in the closed chamber 110. The control element 90 generates a broadband signal and is used to control the operation of the gas analyzer 100. The transmitting element 130 is used to excite the resonance energy (frequency) of the gas with a broadband signal. The receiving element 140 is used to receive the resonance energy (frequency) of the gas and convert it into another broadband signal. The measuring element 150 is used to measure the resonance energy (frequency) of the gas within a fixed distance between the sending end 112 and the receiving end 114 of the closed chamber 110 to determine the sound velocity of the gas, and then analyze the properties and composition of the gas. The positions of the gas inlet 116 and the gas outlet 118 are interchangeable. It should be noted that although the structure of the gas analysis device in FIG. 1 is shown in an exploded manner, in practice, the closed chamber 110 of the gas analysis device 10 is a closed space made of 316L or 304 stainless steel. That is, gas can flow inside the closed chamber 110. The gas contained therein may also be a mixed gas of known composition, therefore, it is also possible that more than two gases are in the enclosed chamber 110 at the same time.

The enclosed chamber 110 further includes an acoustic impedance material layer 160, which can be disposed on the inner wall of the enclosed chamber 110, has a resistance effect, and is used to adjust the acoustic impedance. The acoustic impedance material layer 160 is applied at least one thin film layer at the discontinuous corner of the enclosed chamber 110. When the acoustic energy meets the corner, part of the sound wave will be reflected, diffracted or scattered, resulting in a spurious wave, resulting in loss of acoustic energy. Therefore, at least one layer of acoustic impedance material can be plated on the surface discontinuity to absorb the reflected sound wave to avoid the sound wave diffraction from disturbing the equilibrium acoustic energy transfer.

The acoustic impedance material layer 160 is at least one film layer, and a low acoustic impedance material may be used, for example, selected from polyimide (Polyimide) film, fluoropolymer (Fluoropolymer), epoxy (Epoxy), and polyester (Polyester) ) And Polyurethane. The acoustic impedance material layer 160 adjusts its acoustic impedance by adjusting the thickness of the at least one thin film layer. The thickness of at least one film layer is between 0.0001 inches and 0.01 inches. At least one thin film layer can also reduce the equivalent acoustic impedance of the thin film by making holes in the thin film, which can effectively reduce the transmission loss and minimize the matching difference with the acoustic impedance of the gas.

Among them, the volume of the closed chamber 110 is greater than 100 cm ³ or more to provide a resonance effect with a high quality factor. Please refer to FIG. 2, the transmitting element 130 can use a first broadband electro-acoustic transducer 210 to convert an electrical energy signal into an acoustic signal; the receiving element 140 can also use a second broadband electro-acoustic transducer 310, Used to convert an acoustic signal into an electrical energy signal. The wide-band electroacoustic transducers 210 and 310 further include protective shells 132 and 142, so that the wide-band transducer is protected inside the protective shell.

力學能

聲能，換能器是利用在恆定強磁場中導體經電磁感應產生運動而帶動導體附近的空氣振動，根據運動導體又型態可以分成移動線圈(moving coil)和平面化帶式狀線圈(planar ribbon coil)等類型。其中移動線圈換能器須連接圓錐形或球頂形隔膜，當線圈通電時，線圈受電磁感應而推動隔膜產生振盪運動而發出聲波，此運動為單一方向；然而平板面化帶狀換能器是將一印刷電路鍍在平坦面化隔膜上，即將線圈和隔膜合併在同一平面，鍍有線圈的隔膜置於強磁場中，當電路通電或接收聲波時，位於強磁場的線圈就會產生洛倫茲力進行正弦波運動，而線圈的疏密性改變而隔膜產生撓曲，隔膜兩側皆可推動氣流傳遞聲波，具有雙向性。相較於傳統移動線圈換能器的圓錐狀隔膜內的氣室共振，使用平面化帶狀換能器的隔膜則無此失效空間的影響，進而影響腔內氣體共振效能。此外平面化帶狀之隔膜質量更輕、反應速度更快、失真更低、耐用性更長，並且隔膜散熱面積大，能夠輕易將多餘廢熱 逸散出去，在整個發聲頻段內阻抗保持定值，提供訊號放大器均勻的電阻抗，使其易於驅動。若在隔膜外加裝柵板，更可以降低聲波相互干擾，提升解析度和準確性。亦可透過增強磁場以增強聲能，達到較佳的共振頻率的解析度與準確性。 The broadband electroacoustic transducers 210, 310 may be selected from electric electroacoustic transducers, electromagnetic electroacoustic transducers, electrostatic electroacoustic transducers, or piezoelectric electroacoustic transducers. The basic components of electroacoustic transducers include electrical systems and mechanical vibration systems. Broadband electroacoustic transducers interact with each other between electrical signals and mechanical vibration through electromagnetic induction or deformation caused by changes in electricity and magnetic fields. When designing a wideband electroacoustic transducer, the electrical impedance matching of the signal input and output circuits of the electrical system, amplifiers, etc., as well as the acoustic impedance matching of the material surface of the vibration system and the gas in the cavity, must be considered simultaneously. At present, the widely used electric electroacoustic transducer has an energy transmission path of electric energy

Mechanical energy

Acoustic energy, the transducer is to use a conductor in a constant strong magnetic field to generate air motion near the conductor by electromagnetic induction. According to the shape of the moving conductor, it can be divided into a moving coil and a planar ribbon coil. ribbon coil) and other types. The moving coil transducer must be connected to a conical or dome-shaped diaphragm. When the coil is energized, the coil is subjected to electromagnetic induction to drive the diaphragm to generate an oscillating motion and emit sound waves. This motion is in a single direction; however, the flat surface ribbon transducer is A printed circuit is plated on a flat diaphragm, that is, the coil and the diaphragm are merged in the same plane. The coil-coated diaphragm is placed in a strong magnetic field. When the circuit is energized or receives sound waves, the coil located in the strong magnetic field will generate Loren The sine wave movement is carried out by the force, and the density of the coil is changed and the diaphragm is flexed. Both sides of the diaphragm can push the air flow to transmit sound waves, which is bidirectional. Compared with the resonance of the gas chamber in the conical diaphragm of the traditional moving coil transducer, the diaphragm using the planarized ribbon transducer has no effect of this failure space, which in turn affects the gas resonance efficiency in the cavity. In addition, the flat ribbon diaphragm has lighter quality, faster response speed, lower distortion, longer durability, and the diaphragm has a large heat dissipation area, which can easily dissipate excess waste heat and maintain a constant impedance throughout the sound generation frequency band. Provide a uniform electrical impedance of the signal amplifier, making it easy to drive. If a grid plate is installed outside the diaphragm, it can reduce the mutual interference of sound waves and improve the resolution and accuracy. It can also enhance the acoustic energy by enhancing the magnetic field to achieve better resolution and accuracy of the resonance frequency.

The transmitting element 130 and the receiving element 140 are disposed inside the closed chamber 110, so that both sides of the transmitting element 130 and the receiving element 140 are subjected to the same pressure to eliminate damage and influence caused by overpressure or rapid decompression.

The gas analyzer 100 further includes a heating element 172, which can heat the gas analyzer 100 to avoid gas deposition with high viscosity, which affects the resolution and accuracy of the resonance frequency. The heating element 172 can further heat the gas analyzer 100 to degas (Degas) before replacing the measurement gas, so as to volatilize the non-measurement gas attached to the closed chamber 110, thereby reducing the error during measurement. In addition to the heating element 172, the gas analyzer 100 also includes several temperature sensors 170, which are placed in the enclosed chamber 110. In addition to being used with a heater to control the temperature, the temperature of the gas can be accurately measured. The temperature sensor 170 may be a thermistor, a thermocouple, or a platinum temperature sensor, etc., which is disposed in the enclosed chamber 110, close to the transmitting end 112 or the receiving end 114, so as to reduce the influence on acoustic transmission and resonance. Preferably, the temperature sensor 170 is a thermistor.

The gas analyzer 100 further includes a pressure sensing element 180 that is disposed inside the enclosed chamber 110 or may be disposed at the gas inlet 116 or the gas outlet 118 as close to the enclosed chamber 110 as possible to accurately measure the gas pressure.

The control element 90 includes a general programmable logic controller (PLC) or a digital electronic device with a microprocessor for automatically controlling the operation of the gas analyzer 100 and generating a broadband signal (first broadband signal), It is possible to execute control commands and collect information about the gas analyzer 100.

The measuring element 150 is electrically connected to the receiving element 140, which mainly includes an arithmetic element and a memory. The computing element may be a central processing unit. Measuring element 150 is based on digital signals Fast Fourier Transform (FFT) model of Digital Signal Processing (DSP), converts the acoustic energy of the received gas into a sound spectrum, from 0 to 1 MHz, and analyzes it in real-time (Real-time correlation analysis) correlation analysis) to determine the resonance frequency of the gas. The acoustic spectrum of the acoustic energy of the gas received by the receiving element 140 is from 0 to 1 MHz. Lorentzian fitting is used to correspond to the acoustic spectrum of the acoustic energy of the received gas to obtain a fine gas resonance Frequency resolution, and the speed of sound is determined by the resonance frequency.

其中，W ₀是理想氣體聲速，γ₀是標準狀態下熱容比，M是莫耳質量(kg/mol)，T是絕對溫度(K)，R理想氣體常數(8.3144621J/K-mol)。 W是真實氣體聲速(m/s)，若氣體是多元氣體混合物，則γ和M由混合物中每種氣體的性質及其莫耳分數決定。K _C 和K _V 是真實氣體的熱容比修正及聲學維里修正，都是氣體的溫度和壓力相關函數；K _R 是電聲換能器因氣體壓力波動造成的共振頻率偏移修正。透過氣體分析裝置內氣體的熱力學數據，修正了諸如氣體黏滯性與馳豫現象對共振頻率與聲速的影響。故根據真實溫度與真實壓力的測量可精確計算出氣體的真實聲速與性質，進而準確的分析出該氣體的組成成分。 In order to accurately analyze the nature and composition of the gas, the gas analyzer 100 is provided with a temperature sensor 170 for measuring the real temperature of the gas, and a pressure sensing element 180 for measuring the real pressure of the gas. The gas analyzer 10 can input the type of gas to be measured, and by measuring the resonance frequency, temperature ( T ) and pressure ( P ) of the gas, and by calculation, the gas within a fixed distance between the sending end 112 and the receiving end 114 The speed of sound ( W ). The relationship between the nature of the gas and the composition and sound velocity can generally be described by the following formula:

Among them, W ₀ is the ideal gas sound velocity, γ ₀ is the heat capacity ratio in the standard state, M is the molar mass (kg/mol), T is the absolute temperature (K), R ideal gas constant (8.3144621J/K-mol) . W is the true gas sound velocity (m/s). If the gas is a multi-component gas mixture, γ and M are determined by the nature of each gas in the mixture and its mole fraction. K _C and K _V are the heat capacity ratio correction and the acoustic dimensional correction of the real gas, which are both gas temperature and pressure correlation functions; K _R is the correction of the resonance frequency shift of the electroacoustic transducer due to the gas pressure fluctuation. Through the thermodynamic data of the gas in the gas analysis device, the effects such as gas viscosity and relaxation phenomena on the resonance frequency and sound velocity are corrected. Therefore, the true sound velocity and properties of the gas can be accurately calculated based on the measurement of the true temperature and true pressure, and then the composition of the gas can be accurately analyzed.

The gas analysis device 10 determines the sound velocity of the gas by measuring the resonance frequency of the gas in the closed chamber 110. There are two electroacoustic transducers inside the enclosed chamber 110 for exciting and detecting the acoustic resonance frequency of the gas in the enclosed chamber 110.

The gas analysis device 10 can be used in a reactor of a chemical vapor deposition process. Through the resonance frequency determined by the gas analysis device, the sound velocity of the gas used in the reactor can be collected, and the composition of the gas can be known. The gas analysis device 10 may be located at the front, middle, or back of the gas pipeline of the chemical vapor deposition system, that is, the gas analysis device 10 may be located at any place in the gas pipeline where the gas supply system is connected to the chemical vapor deposition system. The chemical vapor deposition system may be an organic metal chemical vapor deposition system, a plasma enhanced chemical vapor deposition system, a microwave plasma chemical vapor deposition system, or a low pressure chemical vapor deposition system.

With reference to FIG. 1, please refer to FIG. 2, which shows a detailed schematic diagram of the transmitting element 130 and a detailed schematic diagram of the receiving element 140 according to the embodiment of the gas analysis device of the present invention. In FIG. 2, the embodiments of the transmission element 130 and the reception element 140 are further described, and they mainly use electromagnetic acoustic transducers. The other relevant components in the gas analysis device 10 are substantially the same as those described in FIG. 1 and will not be repeated here.

The transmitting element 130 excites the resonance energy (frequency) of the gas with a broadband signal of 0 to 1 MHz (another embodiment is 0-36kH or 0-50kHz), and the transmitting element 130 includes a first broadband transducer 210, which is used for Convert the broadband signal (first broadband signal) into mechanical energy to excite the broadband acoustic energy (resonance energy (frequency)) of the gas. The receiving element 140 receives the resonance energy (frequency) of the gas in a wide frequency range of 0 to 1 MHz (another embodiment is 0-36kH or 0-50kHz), and the receiving element 140 includes a second broadband transducer 310, which is used It is used to convert the broadband acoustic energy of the gas into another broadband signal (second broadband signal).

The first broadband transducer 210 and the second broadband transducer 310 are placed in a strong magnetic field (235,335) generated by a strong magnet (230,330). The first broadband transducer 210 and the second broadband transducer 310 are Electromagnetic related ribbon electric electroacoustic transducer (Ribbon Electrodynamic transducer). The first broadband transducer 210 and the second broadband transducer 310 have two basic requirements: one is a constant magnetic field, and the other is an electric coil (alternating current induced magnetic field). The constant magnetic field may be a static magnetic field or a bias magnetic field generated by a permanent magnet strong magnet or an electromagnet.

The first broadband transducer 210 is used to convert electrical energy signals into acoustic signals. The first broadband transducer 210 is placed in a strong magnetic field 235 generated by a strong magnet 230. The strong magnet 230 is selected from neodymium magnets (Nd ₂ Fe ₁₄ B), samarium cobalt magnets (SmCo ₅ ), Sm (Co, Fe, Cu, Zr) ₇ , aluminum nickel cobalt magnets and strontium iron magnets.

The first broadband transducer 210 mainly includes: a first substrate layer 212 and a printed coil circuit 214. The first substrate layer 212 is placed in the constant magnetic field 235 generated by the strong magnet 230, and the printed coil circuit 214 inputs a broadband signal to generate an alternating magnetic field through electromagnetic induction. The magnetic interaction of the AC magnetic field and the constant magnetic field 235 causes the first substrate layer 212 to vibrate (mechanical energy) and the nearby gas to vibrate, thereby exciting the acoustic energy of the gas in the enclosed chamber 110 to generate a broadband acoustic signal (resonance energy) (frequency)). According to application needs, the broadband signal (first broadband signal) can be continuous wave, spike or FM signal and other signal forms, and its frequency range can be 0-1MHz, 0-50kHz or 0-36kHz. The first substrate layer 212 may be a soft film, which has elasticity, toughness, and chemical resistance, and is matched with gas acoustic impedance.

The transmitting element 130 further includes a first conversion layer 250, which is composed of multiple layers of acoustic impedance matching material films and is coupled to the first broadband transducer 210, so that the acoustic impedance of the first broadband transducer 210 is matched to the gas. The acoustic impedance material film includes a metal film 252 and/or a non-metallic film 254, the metal film 252 is in contact with the first broadband transducer 210; the material of the metal film 252 is selected from gold, silver, copper, iron, titanium, aluminum, chromium , Tungsten, tin, zirconium, molybdenum, nickel, and the non-metallic film 254 is between the metal film 252 and the gas, and has chemical resistance; the non-metallic film 254 material is selected from polyimide (Polyimide), Fluoropolymer, Epoxy, Polyester and Polyurethane.

The second broadband transducer 310 is used to convert acoustic signals into electrical energy signals. The second broadband transducer 310 is placed in a strong magnetic field 335 generated by a strong magnet 330. The strong magnet 330 is selected from neodymium magnets (Nd ₂ Fe ₁₄ B), samarium cobalt magnets (SmCo ₅ ), Sm (Co, Fe, Cu, Zr) ₇ , aluminum nickel cobalt magnets and strontium iron magnets.

The second broadband transducer 310 is an electro-acoustic transducer using a strong magnetic field 335, and mainly includes: a second substrate layer 312 and a printed coil circuit 314. Among them, the second substrate layer 312 is placed in the constant magnetic field 335 generated by the strong magnet 330, and receives the broadband acoustic energy (resonance energy (frequency)) of the gas in the enclosed chamber 110 to vibrate, and the printed coil circuit 314 also The two substrate layers 312 vibrate synchronously (mechanical energy), so that the magnetic flux in the printed coil circuit 314 changes, and then the printed coil circuit 314 generates another broadband signal (second broadband signal). The second substrate layer 312 may be a flexible film, which has elasticity, toughness and chemical resistance, and is matched with the acoustic impedance of the gas. Here, because different gas components and compositions have different frequency response characteristics, different gas compositions will have different frequency responses to the broadband signal generated by the transmitting element 130. In other words, different gas compositions will produce different resonance energies (frequency). And another wideband signal (second wideband signal) received and converted by the second wideband transducer 310 in the receiving element 140 will faithfully present this different resonance energy (frequency). In the present invention, the value of resonance energy (frequency) can be calculated by analyzing the received and converted second broadband signal.

In addition, the receiving element 140 further includes a second conversion layer 350, which is composed of multiple layers of acoustic impedance matching material films and is coupled to the second broadband transducer 310 so that the acoustic impedance of the second broadband transducer 310 matches the gas. The acoustic impedance material film includes a metal film 352 and/or a non-metal film 354. The metal film 352 is in contact with the second broadband transducer 310. The material of the metal film 352 is selected from gold, silver, copper, iron, titanium, aluminum, chromium , Tungsten, tin, zirconium, molybdenum, nickel; and the non-metallic film 354 is between the metal film 352 and the gas, and has chemical resistance, the non-metallic film 354 material is selected from polyimide (Polyimide), Fluoropolymer, Epoxy, Polyester and Polyurethane.

The changes in the magnetic field in the first broadband transducer 210 and the second broadband transducer 310 are mainly the changes in the magnetic flux in the constant magnetic fields 235 and 335 caused by the electromagnetic effects of the printed coil circuits 214 and 314, and the magnitude and direction of the magnetic interaction It is affected by the size and direction of the constant magnetic fields 235 and 335.

In the present invention, the first broadband transducer 210 and the second broadband transducer 310 are electromechanical electroacoustic transducers that use electromagnetic mechanisms for non-contact acoustic transmission and reception, and therefore can be matched with the closed chamber 110 The design of the size and shape, and by strengthening the magnetic field strength and current strength, without contact or coupling, get a higher acoustic resonance strength and quality, enhance the signal-to-noise ratio, and reduce noise interference.

Please refer to FIG. 3, which is a flowchart showing an embodiment of the gas analysis method according to the present invention, which mainly implements the method of the gas analysis device 10 of FIG. 1, so the components of the gas analysis device 10 are not described here. The carrier gas may also be a mixed gas of known composition. Therefore, it is also possible that two or more gases are in the closed chamber 110 at the same time. It includes the following steps:

Step S101: Provide at least one closed chamber 110, the closed chamber 110 is provided with a sending end 112, a receiving end 114, a gas inlet 116 and a gas outlet 118.

Step S102: flowing a gas through the closed chamber 110.

Step S103: The controller 90 generates a broadband signal; the broadband signal may be a broadband analog signal, and the frequency range may be 0-1 MHz, 0-50 kHz or 0-36 kHz.

Step S104: The transmitting element 130 converts the broadband signal (first broadband signal) into a broadband mechanical energy; the broadband mechanical energy excites the resonance energy (frequency) of the gas.

Step S105: The receiving element 140 receives the resonance frequency (energy) of the gas; and converts the resonance energy (frequency) into another broadband signal (second broadband signal).

Step S106: The measuring element 150 calculates a resonance frequency value for the signal (second broadband signal).

Step S107: Determine the sound velocity of the gas according to the fixed distance between the sending end 112 and the receiving end 114 of the closed chamber 110 and the resonance frequency of the gas, and then determine the nature and composition of the gas.

FIG. 4 shows a detailed flowchart of step S107 of the gas analysis method according to the present invention. Wherein, step S107: measuring the resonance frequency of the gas includes the following steps: step S107-1: Fast Fourier Transform (FFT) based on digital signal processing (Digital Signal Processing, DSP), the received Another wideband signal converted by the resonance energy (frequency) of the gas is converted into a sound spectrum, from 0 to 1 MHz (another embodiment is 0-36kH or 0-50kHz).

Step S107-2: Real-time correlation analysis is used to determine the resonance frequency of the gas.

Step S107-3: Based on a Lorentzian fitting, corresponding to the sound spectrum of the received gas, to obtain a fine resolution of the resonance frequency of the gas.

The gas analysis device 10 determines the speed of sound of the gas ( W ) by measuring the resonance frequency of the gas in the closed chamber 110. Two electroacoustic transducers of the gas analysis device 10, wherein the first electroacoustic transducer is located at one end in the enclosed chamber 110 to receive a broadband signal (first broadband signal), and convert the broadband signal to mechanical energy (vibration) The resonance energy (frequency) of the gas is excited in the form of an acoustic signal; the second electroacoustic transducer is located at the other end of the enclosed chamber 110, measures the acoustic signal of the gas, and converts the mechanical energy (vibration) to electrical energy Into another broadband signal (second broadband signal). The gas analyzer 100 in the gas analysis device 10 measures: (1) the acoustic resonance frequency in the closed chamber 110 of a high quality factor, and (2) the resonance frequency is converted into Speed of sound.

In order to measure the resonance frequency of the gas in the closed chamber 110, the gas analyzer 100 uses a Fast Fourier Transform (FFT) model based on digital signal processing (DSP), and passes the received signal through the Gas will be the first broadband signal The converted second broadband signal is converted into a sound spectrum from 0 to 1 MHz (another embodiment is 0-36kH or 0-50kHz), and then the real-time correlation analysis (Real-time correlation analysis) is used to determine the resonance frequency of the gas. Therefore, the device can automatically track changes in the nature and composition of the gas without switching measurement and analysis modes. And Lorentzian fitting (Lorentzian fitting) is used to process the sound spectrum data to improve the precision of the frequency resolution, and the resonance frequency measurement can reach a resolution of one millionth. Next, the resonance frequency method and the size of the cavity, that is, the sound velocity of the gas can be determined by the resonance frequency, and the nature and composition of the gas can be measured very accurately. The resolution of the gas analysis device 10 at the speed of sound measurement reaches one thousandth, and its stability is 5 ppm; the resolution of temperature measurement reaches one thousandth, and its stability is 0.005°C; the resolution of concentration measurement reaches one millionth, Its stability is 10ppm. The gas analysis device 10 uses thermodynamic parameters to calculate the absolute concentration of the flowing gas mixture, so it can have high accuracy without correction.

Figure 5 is a schematic diagram of the gas-filled acoustic resonance frequency analyzed in the gas analyzer, where (a) the acoustic impedance material layer or high-quality resonance chamber of the new type is not used; (b) the acoustic impedance material of the new type is used Layer or high-quality resonance chamber. Although different gases have different resonant frequencies, the amplitude ratio of the resonant frequency to noise is still the same, and is determined by the geometry of the closed chamber 110, especially the distance between the transmitter 112 and the receiver 114. For example, spurious resonance peaks generated at the discontinuity of the gas inlet 116 or the gas outlet 118 of the closed chamber 110 may be eliminated due to absorption of acoustic impedance material or high quality factor closed chamber 110.

Obviously, if the acoustic impedance material layer of this new type or high-quality-factor-enclosed chamber is used, the parasitic resonance frequency peaks are high; while using the acoustic impedance material layer of this new-type or high-quality factor resonance chamber, due to acoustics The absorption of the impedance material or the closed chamber with a high quality factor can eliminate parasitic peaks that cannot be fitted with the Lorentz pattern. Therefore, according to the present invention, a gas analyzer using an acoustic impedance material layer or a large volume resonance chamber can obtain a higher Signal to noise ratio.

Therefore, according to the novel gas analysis device and gas analysis method, the stability and sensitivity of the resonance frequency and the resulting sound velocity can be improved and enhanced.

Although the present invention has been disclosed in the foregoing preferred embodiments, it is not intended to limit the present invention. Anyone who is familiar with this art can make various changes and modifications without departing from the spirit and scope of the present invention. As explained above, all types of corrections and changes can be made without destroying the spirit of this new type. Therefore, the scope of protection of this new model shall be subject to the scope defined in the attached patent application.

10: Gas analysis device

90: control element

100: gas analyzer

110: closed chamber

112: sender

114: receiver

116: Gas inlet

118: gas outlet

130: sending element

132: Transmitting element protective shell

140: receiving element

142: Receiver component protective shell

150: measuring element

160: Acoustic impedance material layer

170: temperature sensing element

172: Heating element

180: pressure sensing element

210: the first broadband transducer

310: Second broadband transducer

Claims (17)

A gas analysis device includes: a gas analyzer, which mainly includes: a closed chamber for containing a gas; the closed chamber is provided with a sending end, a receiving end, a gas inlet and a gas outlet, and the An acoustic impedance material layer is provided in the enclosed cavity; a control element generates a first broadband signal and is used to control the operation of the gas analyzer; a transmitting element is arranged at the transmitting end and is used for excitation with the first broadband signal Resonance energy (frequency) of the gas; a receiving element disposed at the receiving end for receiving the resonance energy (frequency) of the gas to be converted into a second broadband signal; and a measuring element based on the second broadband The signal calculates the resonance energy (frequency) of the gas, and then calculates the sound velocity of the gas according to the fixed distance between the sending end and the receiving end of the closed chamber and the resonance energy (frequency) of the gas, and then analyzes the gas Nature and composition. As in the gas analysis device of claim 1, the acoustic impedance material layer is applied to at least one thin film layer at a discontinuous corner of the inner wall of the enclosed chamber, and is selected from a material with a low acoustic impedance coefficient to avoid energy loss due to scattering of sound waves at the corner And interfere with the resonance frequency of the gas, the low acoustic impedance material is selected from: polyimide (Polyimide) film, fluorine-containing polymer (Fluoropolymer), epoxy (Epoxy), polyurethane (Polyurethane). The gas analysis device according to claim 1, wherein the volume of the closed chamber is at least greater than 100 cm ³ . The gas analysis device according to claim 1, wherein the transmission element includes: a first broadband electro-acoustic transducer that excites the resonance energy (frequency) of the gas through the mechanical energy of the broadband signal. The gas analysis device according to claim 4, wherein the transmission element further comprises: a conversion layer, which is composed of a single layer or multiple layers of acoustic impedance matching material films, so that the acoustic impedance of the first broadband electroacoustic transducer is matched to the gas The single-layer or multi-layer acoustic impedance matching material film includes a metal film and/or a non-metal film, the metal film is in contact with the first broadband electro-acoustic transducer, and the material of the metal film is selected from: gold, silver , Copper, iron, titanium, aluminum, chromium, tungsten, tin, zirconium, molybdenum, nickel; the non-metallic film is between the metal film and the gas, and has chemical resistance, the material of the non-metallic film is selected From: Polyimide (Polyimide), Fluoropolymer (Fluoropolymer), Epoxy (Epoxy), Polyester (Polyester) and Polyurethane (Polyurethane). The gas analysis device according to claim 4, wherein the transmitting element further includes: a first protective case, which makes the acoustic impedance of the first wideband electroacoustic transducer and the enclosed chamber mismatch, so that the first wideband The acoustic impedance of the transducer matches the gas; the first broadband transducer is disposed inside the first protective shell. The gas analysis device according to claim 1, wherein the receiving element further includes: a second broadband electro-acoustic transducer, which converts the resonance energy (frequency) into mechanical energy into an electrical energy and converts it into the second broadband signal. The gas analysis device according to claim 7, wherein the receiving element further comprises: a conversion layer composed of a single-layer or multi-layer acoustic impedance matching material film, so that the acoustic impedance of the second broadband electroacoustic transducer is matched to the gas The acoustic impedance film includes a metal film and/or a non-metal film, the metal film is in contact with the second broadband electroacoustic transducer, the material of the metal film is selected from: gold, silver, copper, iron, Titanium, aluminum, chromium, tungsten, tin, zirconium, molybdenum, nickel; the non-metallic film is interposed between the metal film and the gas, and has chemical resistance, and the material of the non-metallic film is selected from: polyacrylic acid Amine (Polyimide), fluorine-containing polymer (Fluoropolymer), epoxy resin (Epoxy), polyester (Polyester) and polyurethane (Polyurethane). The gas analysis device according to claim 7, wherein the receiving element further comprises: a second protective shell, which makes the second broadband electroacoustic transducer and the acoustic impedance of the enclosed chamber not match, so that the second broadband conversion The acoustic impedance of the energy transducer matches the gas; the second broadband transducer is disposed inside the second protective shell. The gas analysis device according to claim 1, wherein the transmission element is inside the closed chamber. The gas analysis device according to claim 1, wherein the receiving element is inside the closed chamber. The gas analysis device according to claim 1, wherein the frequency range of the broadband signal is from 0 to 1 MHz, preferably from 0 to 36 kHz. The gas analysis device according to claim 1, further comprising: a heating element for heating the gas analysis device. The gas analysis device according to claim 1, further comprising: a plurality of temperature sensing elements for detecting the temperature of the gas analysis device and the gas. The gas analysis device according to claim 1, further comprising: a pressure sensing element for detecting the pressure of the gas. The gas analysis device according to claim 1, wherein the measurement element is based on a Fast Fourier Transform (FFT) model of Digital Signal Processing (DSP), and the received resonance energy of the gas (Frequency) The converted second broadband signal is converted into a sound spectrum, from 0 to 1MHz, A real-time correlation analysis was used to determine the resonance frequency of the gas. The gas analysis device of claim 16, wherein the measuring element is based on a Lorentzian fitting for processing the sound spectrum to obtain a fine resolution of the resonance frequency of the gas.

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