An ultrasonic gas concentration detection device

Abstract

The application discloses an ultrasonic gas concentration detection device and relates to the technical field of gas concentration detection devices.The device comprises a detection body, a transducer assembly, a transformer assembly, a connecting piece and a disturbance piece.The transducer assembly comprises a piezoelectric unit and a metal coupling layer.The piezoelectric unit generates mechanical vibration under an electric signal, and the metal coupling layer is attached to the surface of the piezoelectric unit to transmit vibration to the gas medium in the cavity to generate ultrasonic waves.The transformer assembly comprises a transmitting end and a receiving end.The transmitting end is connected to the metal coupling layer to transmit ultrasonic waves, and the receiving end receives the ultrasonic waves after penetrating the gas and converts the ultrasonic waves into an electric signal.The connecting piece is connected to the piezoelectric unit and the transformer assembly.The disturbance piece is suspended in the detection cavity and projects to cover the gas flow path of the gas inlet.The piezoelectric unit drives the disturbance piece to generate a first vibration in a plane that is not parallel to the gas flow direction.The disturbance piece generates a second vibration that is not collinear with the first vibration direction under the action of the inlet gas flow, thereby forming a multi-directional composite disturbance, breaking the gas concentration gradient in the cavity and improving the mixing uniformity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas concentration detection equipment, and in particular to an ultrasonic gas concentration detection equipment. BACKGROUND

[0002] In the semiconductor manufacturing process, vapor deposition processes such as chemical vapor deposition (CVD), metal organic chemical vapor deposition (MOCVD), and atomic layer deposition (ALD) require that the precursor gas or gas mixture be stably and uniformly delivered to the reaction cavity and deposited on the substrate surface to form the target film. In order to ensure that the deposited layer has the required thickness uniformity and composition consistency, the concentration of the gas must be accurately measured and controlled in real time. Especially in complex reactions involving gas, small deviations in gas concentration can have a significant impact on the performance of the film layer.

[0003] At present, there are a wide variety of concentration detection equipment available on the market, which use different sensing technologies such as acoustic technology, optical technology, and mass spectrometry. A variety of gas concentration detection technologies have been applied to online monitoring of gases, among which ultrasonic sensors have received widespread attention due to their fast response and simple structure. This technology indirectly calculates the concentration composition of binary mixed gas by measuring the propagation speed of sound waves in the gas, which is an important means of achieving high-precision, continuous monitoring. However, the propagation speed of ultrasonic waves is highly dependent on the gas mixing state and physical parameters. However, under actual process conditions, due to the complex structure of the reaction cavity and the disturbance or local retention of gas flow, the gas often cannot be fully mixed, resulting in concentration gradients at different locations. This uneven mixing directly affects the propagation speed of ultrasonic waves in the medium, causing deviations between the measured value and the actual concentration, affecting the accuracy of the measurement.

[0004] Therefore, the existing ultrasonic concentration detection technology has the technical problem of limited measurement accuracy when faced with uneven gas mixing in the ultrasonic chamber, which is a key technical problem that needs to be broken through. SUMMARY

[0005] The purpose of the present application is to provide an ultrasonic gas concentration detection equipment to solve the problem of limited measurement accuracy of the existing ultrasonic concentration detection technology when faced with uneven gas mixing in the ultrasonic chamber.

[0006] To achieve the above-mentioned purpose, the technical solution of the present application is as follows:

[0007] An ultrasonic gas concentration detection equipment, comprising:

[0008] A detection body having a detection chamber formed inside, the detection body being provided with a gas inlet communicating with the detection chamber;

[0009] A transducer assembly includes a piezoelectric unit for receiving an electrical signal and generating mechanical vibration, and a metal coupling layer closely attached to a surface of the piezoelectric unit for transmitting the mechanical vibration to a gaseous medium in a detection chamber to generate an ultrasonic wave;

[0010] A transducer assembly includes a transmitting end and a receiving end symmetrically arranged at two ends of an inner wall of the detection chamber, the transmitting end is connected to the metal coupling layer to transmit the ultrasonic wave to the gaseous medium, and the receiving end is used to capture the ultrasonic wave after penetrating the gas and convert it into an electrical signal;

[0011] A gas uniformization assembly includes a connecting member and a disturbing member, one end of the connecting member is fixedly connected to the piezoelectric unit, and the other end is fixedly connected to the disturbing member, the disturbing member is suspended in the detection chamber, and a projection area of the disturbing member covers a gas flow path of the gas inlet, and the disturbing member is in a non-contact state with the metal coupling layer;

[0012] Wherein, the mechanical vibration of the piezoelectric unit drives the disturbing member to generate a first vibration in a plane non-parallel to the gas flow direction; the disturbing member is configured to generate a second vibration non-collinear with the first vibration direction under the action of the inlet gas flow.

[0013] With the above scheme, the disturbing member of the gas uniformization assembly generates a first vibration non-parallel to the gas flow direction under the drive of the piezoelectric unit, and a second vibration non-collinear with the first vibration under the action of the inlet gas flow, forming a multi-directional composite disturbance, effectively breaking the concentration gradient in the gas flow in the detection chamber. The first vibration of the disturbing member driven by the mechanical vibration and the second vibration generated by the action of the gas flow form a non-collinear composite motion, which promotes the rapid and uniform mixing of the gas, effectively improves the uniformity of the gas mixing, and reduces the error influence of the concentration gradient on the calculation of the sound velocity.

[0014] Further, the disturbing member includes:

[0015] An isolation ring cylinder is fixedly connected to the detection body and has an isolation cavity;

[0016] A plurality of flexible connecting rods are uniformly arranged in the isolation cavity, and a first end of each flexible connecting rod is fixedly connected to the connecting member, and a second end extends out of the isolation ring cylinder into the detection chamber.

[0017] With the above scheme, the core role of the flexible connecting rod is to efficiently transmit the mechanical vibration of the piezoelectric unit and amplify the amplitude through the lever effect to drive the disturbing member to generate a first vibration perpendicular to the gas flow direction; the isolation ring cylinder is rigidly fixed to the detection body to form a physical isolation, on the one hand to block the feedback of vibration energy to the transducer assembly, and on the other hand to constrain the motion of the disturbing member in an independent space to avoid interference of its mechanical structure with the ultrasonic wave propagation path, thereby ensuring the uniformity of gas mixing while maintaining the purity of the acoustic detection environment.

[0018] Further, the second end of the flexible connecting rod is fixedly connected with a disturbance ball, the diameter of the disturbance ball is greater than that of the flexible connecting rod, and the center of the disturbance ball is located on the airflow path of the air inlet.

[0019] With the above scheme, after the disturbance ball is additionally arranged at the end of the disturbance member, and the large-diameter disturbance ball is directly located in the airflow passage, multi-directional random swinging is generated through physical collision and airflow impact; meanwhile, the ball surface induces airflow to form a local vortex, and the composite disturbance mode is formed by superimposing the local vortex and the directional vibration transmitted by the flexible connecting rod. The combination enhances the gas molecule collision frequency in the microscale and effectively eliminates the concentration gradient.

[0020] Further, an elastic sealing ring is sleeved on the end of the flexible connecting rod close to the detection chamber, and the outer wall of the elastic sealing ring is in interference fit with the inner wall of the isolation cylinder.

[0021] With the above scheme, the elastic sealing ring is in interference fit with the inner wall of the isolation cylinder through the outer wall of the elastic sealing ring, and a physical barrier is formed between the inner wall of the isolation cylinder and the outer wall of the elastic sealing ring. The elastic sealing ring effectively blocks the gas in the detection chamber from seeping or flowing into the isolation chamber in the isolation cylinder through the gap between the flexible connecting rod and the inner wall of the isolation cylinder. In addition, when the flexible connecting rod vibrates under the driving of the first end thereof, the flexible connecting rod itself will produce a slight axial displacement. Since the elastic sealing ring is sleeved on the flexible connecting rod, and the material of the elastic sealing ring itself has a certain elasticity, the elastic sealing ring can follow or adapt to the vibration of the flexible connecting rod while maintaining interference sealing with the inner wall of the isolation cylinder, without excessively limiting the movement of the connecting rod.

[0022] Further, an air inlet base is arranged outside the detection body and connected with the air inlet through a communication pipeline, and a pre-gas uniformization pipeline is arranged in the air inlet base. The inlet end of the pre-gas uniformization pipeline is connected with a gas inlet, and the outlet end is connected with the communication pipeline.

[0023] Further, the pre-gas uniformization pipeline comprises:

[0024] an upper pre-gas uniformization passage extending repeatedly in a first direction;

[0025] a lower pre-gas uniformization passage extending repeatedly in a direction opposite to the first direction;

[0026] The outlet end of the upper pre-gas uniformization passage is connected with the inlet end of the lower pre-gas uniformization passage.

[0027] Further, a plurality of gas uniformization protrusions are formed on the inner wall of the pre-gas uniformization pipeline.

[0028] Further, the outer wall of the isolation ring is covered with a damping layer.

[0029] Further, a damper is further included, which is arranged between the detection body and the transducer assembly.

[0030] Further, the transducer assembly includes a first piezoelectric unit and a second piezoelectric unit, which are oppositely arranged at two ends of the detection chamber along the airflow direction.

[0031] The transducer assembly includes a first transducer and a second transducer, which are correspondingly arranged at two sides of the inner wall of the detection body.

[0032] The ultrasonic gas concentration detection device provided by the application has the beneficial effects that: the disturbing member of the gas uniformization assembly generates a first vibration non-parallel to the airflow direction under the driving of the piezoelectric unit, and a second vibration non-collinear with the first vibration is excited under the action of the inlet airflow, forming a multi-directional composite disturbance, which effectively breaks the concentration gradient in the gas flow in the detection chamber. The first vibration of the disturbing member driven by the mechanical vibration and the second vibration generated by the action of the airflow form a non-collinear composite motion, which promotes the rapid and uniform mixing of the gas, effectively improves the uniformity of the gas mixing, and reduces the error influence of the concentration gradient on the calculation of the sound velocity. By using the above scheme, the accuracy of the ultrasonic wave propagation speed measurement is significantly improved, and the problem of limited measurement accuracy caused by uneven gas mixing in the prior art is solved. At the same time, the design is simple in structure and suitable for high-precision industrial scenes sensitive to gas concentration such as semiconductor manufacturing. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 FIG. 1 is a schematic diagram of the overall structure of an ultrasonic gas concentration detection device according to an embodiment of the application;

[0034] Figure 2 FIG. 3 is a partial cross-sectional view of an ultrasonic gas concentration detection device according to an embodiment of the application;

[0035] Figure 3 FIG. 5 is a cross-sectional view of a gas uniformization assembly according to an embodiment of the application;

[0036] Figure 4 FIG. 7 is a cross-sectional view of an isolation ring sleeve according to an embodiment of the application;

[0037] Figure 5 FIG. 9 is a structural cross-sectional view of a detection body according to an embodiment of the application.

[0038] Reference signs: 1, detection body; 11, gas inlet; 111, gas inlet hole; 12, gas outlet; 13, detection chamber; 2, transducer assembly; 21, first piezoelectric unit; 22, second piezoelectric unit; 3, transformer assembly; 31, first transformer; 32, second transformer; 4, connecting piece; 5, disturbance piece; 51, isolation ring cylinder; 52, flexible connecting rod; 53, disturbance ball; 54, sealing ring; 6, gas inlet base; 61, pre-gas uniform pipeline; 7, damper. DETAILED DESCRIPTION

[0039] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application. Unless otherwise defined, the technical terms or scientific terms used herein should be understood as the common meanings of the same to those of ordinary skill in the art to which the present application belongs. The similar words such as “comprise” used herein mean that the elements or objects before the words encompass the elements or objects listed after the words and their equivalents, and do not exclude other elements or objects.

[0040] The specific embodiments of the present application will be further described below with reference to the accompanying drawings. Figure 1 The specific embodiments of the present application will be further described below with reference to the accompanying drawings. Figure 5 The specific embodiments of the present application will be further described below with reference to the accompanying drawings.

[0041] With reference to the accompanying drawings, Figure 1 and Figure 2 In some embodiments of the present application, an ultrasonic gas concentration detection device includes a detection body 1, a transducer assembly 2, a transformer assembly 3 and a gas uniformization assembly.

[0042] In some embodiments of the present application, a detection chamber 13 is formed in the detection body 1, and the detection body 1 is provided with a gas inlet 11 and a gas outlet 12 which communicate with the detection chamber 13; the gas inlet 11 and the gas outlet 12 are oppositely distributed on two sides of the detection body 1. During operation of the ultrasonic gas concentration detection device, the detection chamber can be flushed with chemical vapor deposition (CVD), metal organic chemical vapor deposition (MOCVD) and atomic layer deposition (ALD) gases to be transported to the system. Such gases can be introduced into the detection chamber 13 at the gas inlet 11 and discharged at the gas outlet 12 of the detection chamber 13. In some specific embodiments of the present application, a plurality of gas inlet holes 111 are uniformly radially formed in the inner wall of the detection chamber 13.

[0043] In some embodiments of the present application, the basic principle of ultrasonic gas concentration detection relies on the physical property that the speed of sound propagating in a gas medium is closely related to the composition, concentration and temperature of the gas. In other words, given the temperature and the type of gas, the concentration of the target gas in the gas mixture to be measured can be deduced by measuring the propagation time of the sound wave in the gas, i.e. the time of flight. In some embodiments of the present application, the transducer assembly 2 includes a piezoelectric unit for receiving an electrical signal and generating mechanical vibrations, and a metal coupling layer (not shown in the figure) closely attached to the surface of the piezoelectric unit for transmitting the mechanical vibrations to the gas medium in the detection chamber 13 to generate ultrasonic waves; the transducer assembly 3 includes a transmitting end and a receiving end symmetrically arranged at the two ends of the inner wall of the detection chamber 13, the transmitting end being connected to the metal coupling layer for transmitting ultrasonic waves to the gas medium, and the receiving end being used to capture the ultrasonic waves after penetrating the gas and convert them into electrical signals. Among them, the piezoelectric unit generates mechanical vibrations due to the inverse piezoelectric effect under the driving of the electrical signal, and the mechanical vibrations are effectively transmitted to the gas medium in the detection chamber 13 through the metal coupling layer and the transducer assembly 2, thereby forming a stable ultrasonic wave signal in the chamber. The transmitting end of the transducer assembly 3 is used to transmit ultrasonic waves to the gas medium in the chamber; the receiving end is located at the other end of the ultrasonic wave propagation path, used to receive the ultrasonic wave signal after penetrating the gas and convert it into an electrical signal transmitted to the externally connected signal analysis module (not shown in the figure).

[0044] Referring to Figure 2 In some specific embodiments of the present application, the transducer assembly 2 includes a first piezoelectric unit 21 and a second piezoelectric unit 22, which are oppositely arranged at the two ends of the detection chamber 13 along the direction of gas flow; the transducer assembly 3 includes a first transducer 31 and a second transducer 32, which are correspondingly arranged on the two sides of the inner wall of the detection body 1. During the process of ultrasonic waves penetrating the gas to be measured in the detection chamber 13, the propagation speed of the ultrasonic waves will be affected by the composition and concentration distribution of the gas. By comparing the time difference between the transmitted and received ultrasonic wave signals, the propagation time of the ultrasonic waves can be calculated, and combined with the real-time collected gas temperature data, the mapping relationship model between the sound speed and the gas concentration is used to deduce the concentration value of the component to be measured in the gas.

[0045] Referring to Figure 2In some embodiments of the present application, the piezoelectric unit comprises a single piezoelectric material plate. In other embodiments, the first piezoelectric unit 21 and / or the second piezoelectric unit 22 can comprise a plurality of piezoelectric material plates arranged in a stack extending away from the detection chamber 13. In specific embodiments, the piezoelectric assemblies constituting the first piezoelectric unit 21 and the second piezoelectric unit 22 are arranged to vibrate relative to the horizontal ends of the detection chamber 13, such that the acoustic signal is primarily transmitted as directly across the detection chamber 13.

[0046] Referring to Figure 3 and Figure 4 In some embodiments of the present application, the gas homogenizing assembly comprises a connecting member 4 and a disturbing member 5, one end of the connecting member 4 is fixedly connected to the vibration output surface of the piezoelectric unit, and the other end is fixedly connected to the disturbing member 5. In some embodiments of the present application, the connecting member 4 is an elastic connecting rod. The disturbing member 5 is suspended in the detection chamber 13, and the projection area of the disturbing member 5 covers the airflow path of the gas inlet 11, and the disturbing member 5 is in a non-contact state with the metal coupling layer; wherein the mechanical vibration of the piezoelectric unit drives the disturbing member 5 to generate a first vibration in a plane non-parallel to the airflow direction; the disturbing member 5 is configured to generate a second vibration non-collinear with the first vibration direction under the action of the inlet airflow. The disturbing member 5 of the gas homogenizing assembly generates a first vibration non-parallel to the airflow direction under the drive of the piezoelectric unit, and a second vibration non-collinear with the first vibration under the action of the inlet airflow, forming a multi-directional composite disturbance, effectively breaking the concentration gradient in the gas flow in the detection chamber 13. The first vibration of the disturbing member 5 driven by mechanical vibration and the second vibration generated by the action of the airflow form a non-collinear composite motion, which promotes rapid and uniform mixing of the gas, effectively improves the uniformity of gas mixing, and reduces the error influence of concentration gradient on sound velocity calculation. With the above scheme, the accuracy of ultrasonic wave propagation speed measurement is significantly improved, and the problem of limited measurement accuracy caused by uneven gas mixing in the prior art is solved. At the same time, the design is simple in structure and suitable for high-precision industrial scenes such as semiconductor manufacturing which are sensitive to gas concentration.

[0047] In some embodiments of the present application, the disturbing member 5 comprises a plurality of flexible links 52, and an isolation cylinder 51 is fixedly connected to the detection body 1 and has an isolation cavity. The plurality of flexible links 52 are arranged in a uniform and circumferential array in the isolation cavity, and a first end of each flexible link 52 is fixedly connected to the connecting member 4, and a second end extends out of the isolation cylinder 51 into the detection chamber 13. The flexible link 52 efficiently transmits the mechanical vibration of the piezoelectric unit and amplifies the amplitude through the lever effect, drives the disturbing member 5 to generate the first vibration perpendicular to the airflow direction; the isolation cylinder 51 is rigidly fixed to the detection body 1 to form physical isolation, on the one hand, to block the vibration energy feedback to the transducer assembly 2, and on the other hand, to constrain the movement of the disturbing member 5 in an independent space, avoiding the mechanical structure of the disturbing member 5 to interfere with the ultrasonic wave propagation path, so as to ensure the uniformity of the gas mixture while maintaining the purity of the acoustic detection environment.

[0048] In some other embodiments of the present application, the flexible link 52 can be made of PFA (perfluoroalkoxy) or PTFE (polytetrafluoroethylene) coated stainless steel wire, the inner core ensures the strength, and the outer coating layer provides chemical inertness and low particle shedding, which is suitable for fluorine-containing gas or high corrosive precursor environment. In some other embodiments, the flexible link 52 is made of metal tantalum or molybdenum wire, and the surface is treated by plasma ceramic coating (such as Y2O3 or Al2O3), which takes into account the mechanical strength and surface inertness, and is suitable for medium and high temperature MOCVD process scenarios.

[0049] In some embodiments of the present application, in order to enhance the disturbance effect, a disturbing ball 53 is fixedly connected to the second end of the flexible link 52, the diameter of the disturbing ball 53 is greater than the diameter of the flexible link 52, and the center of the ball is located on the airflow path of the gas inlet 11, so that the high-speed airflow directly impacts the disturbing ball 53. Under the excitation of the piezoelectric unit, the flexible link 52 drives the disturbing ball 53 to generate mechanical vibration in the first direction in the plane perpendicular to the airflow direction; at the same time, the airflow impacts the disturbing ball 53 to form random disturbance, so that the disturbing ball 53 further generates additional vibration in the second direction which is not collinear with the first direction, and finally forms a non-collinear composite disturbance path in the detection chamber 13, effectively breaking the laminar gas structure and eliminating the concentration gradient.

[0050] In some embodiments of the present application, the perturbation ball 53 is a hollow thin-shell sphere made of corrosion-resistant alloy, such as silicon nitride, which has high hardness and corrosion resistance, and is suitable for use in high-temperature processes where plasma may exist, thereby reducing inertial load and improving vibration response sensitivity. Alternatively, the perturbation ball 53 can be made of polymer material by injection molding, which can achieve low cost and chemical compatibility, and can also avoid the generation of particulate impurities. In other embodiments, the perturbation ball 53 can be provided with microstructures, such as spiral grooves or grid micro-holes, which can guide the formation of eddy currents during perturbation to form a perturbation zone that is interleaved with the main gas flow, thereby further improving mixing efficiency.

[0051] Referring to Figure 3 In some embodiments of the present application, the flexible link 52 is provided with an elastic sealing ring 54 at one end near the detection chamber 13, and the outer wall of the elastic sealing ring 54 is in interference fit with the inner wall of the isolation cylinder. The elastic sealing ring 54 is in interference fit with the inner wall of the isolation cylinder 51 through its outer wall, and a physical barrier is formed between the inner wall of the isolation cylinder 51 and the outer wall of the elastic sealing ring 54. The elastic sealing ring 54 effectively blocks the gas in the detection chamber 13 from seeping or flowing into the isolation chamber inside the isolation cylinder 51 through the gap between the flexible link 52 and the inner wall of the isolation cylinder 51. In addition, when the flexible link 52 is driven to vibrate at its first end, the flexible link 52 itself will produce a small axial displacement. Since the elastic sealing ring 54 is sleeved on the flexible link 52, and the material of the elastic sealing ring 54 itself has a certain elasticity, the elastic sealing ring 54 can follow or adapt to the vibration of the flexible link 52 while maintaining interference fit with the inner wall of the isolation cylinder 51, without excessively restricting the movement of the flexible link 52.

[0052] In order to ensure fluid isolation between the uniformization assembly and the detection environment, in other embodiments of the present application, the flexible link 52 is provided with an elastic sealing ring 54 at one end near the detection chamber 13, and the outer wall of the sealing ring 54 is in interference fit with the inner wall of the isolation cylinder 51. This structure provides sealing elastic compensation in the vibration state, which effectively blocks the gas in the detection chamber 13 from seeping into the isolation chamber through the link gap, and at the same time allows the flexible link 52 to maintain a certain axial displacement in the vibration state, thereby ensuring the flexible responsiveness and structural integrity of the uniformization assembly. Such design not only ensures the perturbation function, but also maintains the stability and cleanliness of the acoustic propagation environment between the transducer assembly 2 and the detection chamber 13.

[0053] Referring to Figure 5In some embodiments of the present application, an air inlet base 6 is further included, which is arranged outside the detection body 1 and is connected to the air inlet 11 through a communication pipeline. A pre-homogenizing pipeline 61 is arranged in the air inlet base 6, the inlet end of the pre-homogenizing pipeline 61 is connected to a gas inlet, and the outlet end is connected to the communication pipeline. Compared with the conventional gas directly entering the detection chamber 13 from the outside, this structure realizes preliminary homogenization by pre-treating the gas in the air inlet base 6, such as disturbance, flow division or pressure equalization, before the gas enters the detection body 1. The problems of local flow stagnation, gas velocity gradient and gas concentration unevenness caused by “passive diffusion” after entering the detection chamber 13 can be greatly reduced. In the semiconductor chemical deposition process, the pressure field and concentration field of the detection chamber 13 are very sensitive to the gas. The above structure improves the air inlet stability and helps to realize the consistency of the acoustic signal propagation path in the detection process, thereby improving the precision and response speed of ultrasonic gas detection.

[0054] In some specific embodiments of the present application, the pre-homogenizing pipeline 61 includes an upper pre-homogenizing channel and a lower pre-homogenizing channel. The upper pre-homogenizing channel extends repeatedly in a first direction. The lower pre-homogenizing channel extends repeatedly in a direction opposite to the first direction. The outlet end of the upper pre-homogenizing channel is connected to the inlet end of the lower pre-homogenizing channel. Through the upper and lower pre-homogenizing channel structure, the mixing uniformity and flow stability of the gas before entering the detection chamber 13 are further enhanced. Specifically, the upper channel and the lower channel repeatedly bend in opposite directions to form a turn-back flow path, so that the gas experiences multiple direction changes, flow disturbances and path extensions before entering the detection chamber 13, thereby effectively dispersing the original flow, balancing the pressure distribution and reducing the uneven flow state caused by turbulence. The above structure design not only prolongs the residence time of the gas in the pre-treatment area and enhances the intermolecular mixing, but also realizes efficient pre-homogenization without significantly increasing the device volume, further improving the accuracy and response consistency of subsequent ultrasonic detection, especially suitable for high-precision application scenarios such as semiconductor chemical deposition process which is sensitive to gas distribution.

[0055] In some specific embodiments of the present application, the inner wall of the pre-homogenizing pipeline 61 is protruded to form a plurality of homogenizing protrusions (not shown in the figure). In some embodiments, the homogenizing protrusions of the pre-homogenizing pipeline 61 are integrally formed by injection molding, precision casting or other processes. The homogenizing protrusions form a turbulence structure inside the pre-homogenizing pipeline 61, which can disturb the originally linear gas flow field, promote the diffusion, rotation or flow division of the gas flow in the pipeline, and thus preliminarily realize the homogenization of the gas before flowing to the detection chamber 13, effectively avoiding the influence of local gas concentration or pressure fluctuation on the detection accuracy.

[0056] In some embodiments of the present application, the outer wall of the isolation cylinder 51 is covered with a damping layer. In some other embodiments of the present application, a damper 7 is further included, which is arranged between the detection body 1 and the transducer assembly 3. The materials of the damper 7 and the damping layer can be selected to have a high acoustic attenuation coefficient and a thermal expansion coefficient (CTE) close to or similar to that of piezoelectric materials. The damping layer material with these properties can not only attenuate the impact of vibration on the isolation cylinder 51 and the outside, improve its service life, but also attenuate unwanted acoustic signals and suppress the hum.

[0057] In summary, the present application realizes the completion of gas disturbance and homogenization without external power source through unique structural design, significantly improving the accuracy and stability of ultrasonic gas concentration detection. Inside the detection chamber 13, the mechanical vibration generated by the piezoelectric unit itself under the inverse piezoelectric effect drives the disturbance member 5 suspended in the airflow path to realize the first direction disturbance; at the same time, the high-speed airflow directly impacts the disturbance ball 53 during the gas inlet process, exciting it to generate a second disturbance in a non-collinear direction. This double disturbance mechanism not only fully breaks the laminar flow structure of the gas, quickly and uniformly mixes the gas in the chamber, effectively reduces the acoustic velocity error caused by the concentration gradient, but also, since the entire disturbance process is driven by the body structure and the gas itself, without the need for external power sources such as motors or fans, it reduces the complexity of the detection system and meets the compactness requirements of the semiconductor field. In addition, the disturbance member 5 is connected to the isolation cylinder 51 through a flexible connecting rod 52, and is provided with an elastic sealing ring 54, realizing the physical isolation of the disturbance assembly and the inside of the detection chamber 13, ensuring that no particles or other contaminants are introduced during the disturbance process, protecting the high cleanliness requirement of the detection chamber 13, and being suitable for process scenarios of semiconductors which are extremely sensitive to gas purity. Furthermore, the present application is provided with an air inlet base 6 outside the detection body 1, an internal pre-homogenizing pipeline 61, and a curved channel and a homogenizing protrusion arranged inside, realizing the first step disturbance and preliminary homogenization before the gas enters the detection chamber 13; cooperating with the disturbance member 5 in the detection chamber 13 to complete the second step fine disturbance and deep mixing, thereby constructing a two-stage homogenization scheme of "pre-homogenization and real-time disturbance". Further, without the need for additional power and complex control, the ultrasonic gas concentration detection capability with high responsiveness, high precision, and adaptability to high corrosion / high temperature working conditions is realized, and the detection accuracy can be improved from the range of 20-50ppm to 4-10ppm through comparative measurement.

[0058] Although the embodiments of the present application have been described in detail above, it is obvious to those skilled in the art that various modifications and changes can be made to these embodiments. However, it should be understood that such modifications and changes are within the scope and spirit of the present application. Moreover, the present application described herein can have other embodiments and can be implemented or realized in various ways.

Claims

1. An ultrasonic gas concentration detection apparatus characterized by comprising: The application relates to a gas concentration detection device, which comprises the following components: a detection body (1) internally formed with a detection chamber (13), the detection body (1) being provided with an air inlet (11) communicating with the detection chamber (13); a transducer assembly (2) comprising a piezoelectric unit for receiving an electric signal and generating mechanical vibration and a metal coupling layer closely adhering to the surface of the piezoelectric unit for transmitting the mechanical vibration to a gas medium in the detection chamber (13) to generate ultrasonic waves; a transformer assembly (3) comprising a transmitting end and a receiving end symmetrically arranged at two ends of the inner wall of the detection chamber (13), the transmitting end being connected with the metal coupling layer to transmit ultrasonic waves to the gas medium, and the receiving end being used for capturing the ultrasonic waves after penetrating the gas and converting the ultrasonic waves into an electric signal; a uniform gas assembly comprising a connecting piece (4) and a disturbance piece (5), one end of the connecting piece (4) being fixedly connected with the piezoelectric unit, the other end of the connecting piece (4) being fixedly connected with the disturbance piece (5), the disturbance piece (5) being suspended in the detection chamber (13), and the projection area of the disturbance piece (5) covering the airflow path of the air inlet (11), the disturbance piece (5) and the metal coupling layer being in a non-contact state; wherein the mechanical vibration of the piezoelectric unit drives the disturbance piece (5) to generate a first vibration in a plane non-parallel to the airflow direction; the disturbance piece (5) is configured to generate a second vibration non-collinear with the first vibration direction under the action of the inlet airflow.

2. The ultrasonic gas concentration detection device according to claim 1, wherein The disturbance piece (5) comprises: an isolation ring cylinder (51) fixedly connected with the detection body (1) and having an isolation cavity; a plurality of flexible connecting rods (52) uniformly arranged in the isolation cavity, the first end of each flexible connecting rod (52) being fixedly connected with the connecting piece (4), and the second end of each flexible connecting rod (52) extending out of the isolation ring cylinder (51) into the detection chamber (13).

3. An ultrasonic gas concentration detection device according to claim 2, wherein The second end of the flexible connecting rod (52) is fixedly connected with a disturbance ball (53), the diameter of the disturbance ball (53) being greater than that of the flexible connecting rod (52), and the center of the disturbance ball (53) being located on the airflow path of the air inlet (11).

4. The ultrasonic gas concentration detection device according to claim 2, wherein The end of the flexible connecting rod (52) close to the detection chamber (13) is sleeved with an elastic sealing ring (54), and the outer wall of the elastic sealing ring (54) is in interference fit with the inner wall of the isolation ring cylinder (51).

5. An ultrasonic gas concentration detection device according to claim 4, wherein The application further comprises an air inlet base (6) arranged outside the detection body (1) and connected with the air inlet (11) through a communication pipeline, the air inlet base (6) being provided with a pre-uniform gas pipeline (61) therein, the inlet end of the pre-uniform gas pipeline (61) being connected with a gas inlet, and the outlet end of the pre-uniform gas pipeline (61) being connected with the communication pipeline.

6. An ultrasonic gas concentration detection device according to claim 5, wherein The pre-uniform gas pipeline (61) comprises: an upper-layer pre-uniform gas passage repeatedly bending and extending along a first direction; a lower-layer pre-uniform gas passage repeatedly bending and extending along a direction opposite to the first direction; wherein the outlet end of the upper-layer pre-uniform gas passage is communicated with the inlet end of the lower-layer pre-uniform gas passage.

7. An ultrasonic gas concentration detection device according to claim 6, wherein A plurality of uniform gas protrusions are formed on the inner wall of the pre-uniform gas pipeline (61).

8. The ultrasonic gas concentration detection device according to claim 3, wherein The outer wall of the isolation ring cylinder (51) is covered with a damping layer.

9. The ultrasonic gas concentration detection device according to claim 1, wherein A damper (7) is also included, which is arranged between the detection body (1) and the transducer assembly (3).

10. The ultrasonic gas concentration detection device according to claim 1, characterized in that: The transducer assembly (2) comprises a first piezoelectric unit (21) and a second piezoelectric unit (22), which are oppositely arranged at two ends of the detection chamber (13) along the airflow direction; The transducer assembly (3) comprises a first transducer (31) and a second transducer (32), which are correspondingly arranged on both sides of the inner wall of the detection body (1).

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