Packaging structure based on MEMS flow sensor

Abstract

The invention discloses a packaging structure based on an MEMS (Micro Electro Mechanical System) flow sensor. The packaging structure based on the MEMS flow sensor comprises a flow channel shell, a PCB (Printed Circuit Board) and a detection chip, the flow channel shell comprises a shell body and two pipe tables, a sample injection flow channel is formed in the bottom of the shell body, the PCB covers the outer side of the sample injection flow channel to form a flow channel cavity, through grooves are formed in the pipe tables, and outlets in the bottoms of the through grooves are communicated with the flow channel cavity; the detection chip is embedded in the PCB, and the detection chip is located in the flow channel cavity. According to the invention, the PCB covers the outer side of the sample injection flow channel to form the flow channel cavity, and the detection chip is arranged in the flow channel cavity, so that the flow parameter of the medium in the flow channel cavity is detected.

Description

Technical Field

[0001] This invention relates to the field of flow sensor technology, and in particular to a packaging structure based on a MEMS flow sensor. Background Technology

[0002] MEMS, or Micro-Electro-Mechanical Systems, is a technology that combines micro-machining and microelectronics. Compared to traditional flow sensors, MEMS flow sensors offer significant advantages such as miniaturization, high precision, fast response, low power consumption, high integration, and high reliability. Based on their working principle, MEMS flow sensors can be broadly categorized into three types: piezoelectric, piezoresistive, and thermal transfer. Thermal transfer flow sensors utilize temperature changes to determine flow rate, requiring no mechanically moving miniature components for measurement; therefore, they exhibit higher stability and longer lifespan.

[0003] The working principle of a heat transfer flow sensor is to obtain the fluid flow rate by measuring the temperature change of the temperature-sensing resistors on both sides of a heater. When there is no flow, the resistors on both sides have the same temperature and therefore equal resistance. However, when fluid flows, the temperature distribution on both sides becomes asymmetrical, resulting in a difference in resistance, which is then used to obtain the voltage change value through a Wheatstone bridge. Different flow rates lead to different temperature distributions, thus producing different output voltages, ultimately establishing a correspondence between flow rate and output voltage.

[0004] The encapsulation channel of a MEMS flow sensor is the core interface connecting the external fluid and the sensor chip. It undertakes the key functions of stable flow guidance, thermal isolation, mechanical protection, and environmental shielding. Its design directly affects the sensor's measurement accuracy, long-term stability, and environmental adaptability.

[0005] Existing patent 1 (US9952079B2) discloses a flow sensor. This solution uses an S-shaped flow channel, which has a certain effect of smoothing the medium flow rate. However, the overall structure has a low utilization rate of the flow channel area, resulting in a large overall space occupation.

[0006] Existing patent 2 (US7757553B2) discloses a flow detector with a housing. This solution adopts a split installation structure, and the housing structure corresponding to the flow channel is complex with many parts, making installation difficult. In mass production, it is difficult to ensure product consistency, and there is also a lack of corresponding filtration devices to solve the problem of interference from impurities.

[0007] In MEMS flow sensor design, laminar flow is a favorable stable flow state (ensuring measurement accuracy), while eddies and turbulence may cause interference (which needs to be suppressed through flow channel optimization, filtering devices, etc.). Therefore, there is an urgent need for a packaging structure based on MEMS flow sensors to solve the problems of existing MEMS flow sensor packaging being susceptible to turbulence and difficult to standardize. Summary of the Invention

[0008] In view of the above problems, the present invention is proposed to provide a packaging structure for a MEMS flow sensor that overcomes or at least partially solves the above problems.

[0009] Other features and advantages of the invention will become apparent from the following detailed description, or may be learned in part by practice of the invention.

[0010] This invention provides a packaging structure based on a MEMS flow sensor. The packaging structure includes a flow channel shell, a PCB board, and a detection chip. The flow channel shell includes a housing and two tube platforms. A sample inlet channel is provided at the bottom of the housing. The PCB board covers the outside of the sample inlet channel to form a flow channel cavity. The tube platforms are provided with through slots, and the outlet at the bottom of the slots communicates with the flow channel cavity. The detection chip is embedded on the PCB board and is located inside the flow channel cavity.

[0011] In some embodiments of the present invention, the flow channel shell is integrally formed; the integral forming process is injection molding, injection molding, or compression molding.

[0012] In some embodiments of the present invention, a stepped groove is provided at the bottom edge of the housing, the PCB board is fitted to the stepped groove, and the connection between the PCB board and the stepped groove is sealed with sealant.

[0013] In some embodiments of the present invention, the sample inlet channel is composed of an inner cavity and two outer circulation channels. The two outer circulation channels are symmetrically arranged on both sides of the inner cavity, and the outer port of the outer circulation channel is connected to the inner cavity, while the inner port of the outer circulation channel is connected to the outlet of the through groove.

[0014] In some embodiments of the present invention, an inner boss is provided in the inner cavity, and a smooth inclined surface is provided between the inner boss and the outer circulation channel. The inclined surface is inclined in the direction that the top of the inner boss is inclined towards the bottom surface of the outer circulation channel, and the height of the top of the inner boss is greater than the height of the bottom surface of the outer circulation channel. The width of the inner boss is greater than the width of the outer circulation channel, and the detection chip is positioned directly opposite the inner boss. The width ratio of the inner boss width W1 to the outer circulation channel width W2 is 4:1.

[0015] In some embodiments of the present invention, external protrusions are provided at intervals in the external circulation channel, the top height of the external protrusions is greater than the bottom height of the external circulation channel, and the top of the external protrusions extends toward the bottom of the external circulation channel. In some embodiments of the present invention, the external circulation channel is a vortex structure, including multiple turning angles, the turning angles being 90°, and the turning angles being rounded; the turning angle from the inner port of the external circulation channel to the outer port of the channel is 450°.

[0016] In some embodiments of the present invention, the detection chip is bonded to the PCB board by die bond adhesive and electrically connected to the PCB board by wire bonding; the PCB board is also provided with a receiving groove, the detection chip is disposed in the receiving groove, and the top of the detection chip is flush with the surface of the PCB board.

[0017] In some embodiments of the present invention, the PCB board is provided with flow guide grooves corresponding to the positions of the tube platform, the flow guide grooves are connected to the flow channel ports, the flow guide grooves are provided with positioning and mounting grooves, and the positioning and mounting grooves are provided with filter sections.

[0018] In some embodiments of the present invention, the filter section is arranged horizontally or vertically. The filter section includes a filter screen and a support plate surrounding the outside of the filter screen. The filter screen is a perforated mesh structure. The support plate is disposed in the positioning and mounting groove. The pore size of the filter screen is 80 to 500 mesh. The shape of the filter section matches the shape of the positioning and mounting groove. The filter section is circular or rectangular. When the filter section is horizontally positioned, the positioning and mounting groove is a stepped structure and is horizontally positioned opposite the bottom outlet of the channel. The filter section is circular. When the filter section is vertically positioned, the positioning and mounting groove is formed on opposite sides of the inner wall of the middle area of ​​the guide channel. The sample inlet channel has a filter mounting groove corresponding to the position of the positioning and mounting groove. The filter section is rectangular and is embedded in the positioning and mounting groove and the filter mounting groove.

[0019] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: The packaging structure based on the MEMS flow sensor described in this embodiment of the invention forms a flow channel cavity by covering the outside of the sample inlet channel with the PCB board, and placing the detection chip inside the flow channel cavity, thereby realizing the detection of the flow parameters of the medium inside the flow channel cavity.

[0020] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 An exploded view of the packaging structure of a MEMS flow sensor provided in an embodiment of the present invention; Figure 2 This is a bottom view of the casing; Figure 3 This is a schematic diagram of the bottom structure of the shell; Figure 4 This is a schematic diagram of the filter section. Figure 5 A schematic diagram of the positioning and mounting groove when the filter section is set vertically; Figure 6 A schematic diagram of the structure when the filter section is installed vertically; Figure 7 A schematic diagram of the flow channel housing when the filter section is set vertically.

[0023] Explanation of reference numerals in the attached figures: 1. Housing; 2. PCB board; 3. Detection chip; 4. Filter section; 11. Tube platform; 12. Through groove; 13. Sample inlet channel; 14. Outlet; 15. Connecting ear; 16. Step groove; 17. Filter mounting groove; 20. Guide groove; 21. Needle row; 22. Positioning mounting groove; 41. Support plate; 42. Filter screen; 151. External circulation channel; 152. Inner cavity; 153. Inner port of the channel; 154. Outer port of the channel; 155. Inner boss; 156. Inclined surface; 157. Outer boss. Detailed Implementation

[0024] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings.

[0025] The accompanying drawings illustrate various structural schematics according to embodiments of the present disclosure. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0026] In the context of this disclosure, when a layer / component is referred to as being "above" another layer / component, that layer / component may be directly above the other layer / component, or there may be an intermediate layer / component between them. Additionally, if a layer / component is "above" another layer / component in one orientation, then when the orientation is reversed, that layer / component may be "below" the other layer / component. In the context of this disclosure, similar or identical components may be denoted by the same or similar reference numerals.

[0027] To better understand the above technical solutions, the following will describe the above technical solutions in detail with reference to specific implementation methods. It should be understood that the embodiments of this disclosure and the specific features in the embodiments are detailed descriptions of the technical solutions of the present invention, rather than limitations on the technical solutions of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0028] Figure 1 This is a schematic flowchart of a packaging structure based on a MEMS flow sensor provided in an embodiment of the present invention. Figure 2 This is a bottom view of housing 1, as shown below. Figure 1-2As shown, the packaging structure of the MEMS flow sensor includes: a flow channel shell, a PCB board 2, and a detection chip 3; the flow channel shell includes a housing 1 and two tube platforms 11. The bottom of the housing 1 is provided with a sample inlet flow channel 13. The PCB board 2 covers the outside of the sample inlet flow channel 13 to form a flow channel cavity. The tube platform 11 is provided with a through groove 12, and the outlet 14 at the bottom of the through groove 12 communicates with the flow channel cavity; the detection chip 3 is embedded on the PCB board 2 and is located in the flow channel cavity; the two tube platforms 11 serve as the medium injection port and the medium discharge port, respectively (that is, when one tube platform 11 serves as the medium injection port, the other tube platform 11 serves as the medium discharge port, and the functions of the two can be switched according to actual application requirements). That is, the medium is introduced into the flow channel cavity through one of the tube platforms 11, the detection chip 3 detects and collects the flow rate data of the medium in the flow channel cavity in real time, and the medium finally flows out through the other tube platform 11.

[0029] In this embodiment of the invention, the flow channel shell is integrally formed. The material of the flow channel shell is plastic, ceramic or polymer material, etc. Different manufacturing processes can be adopted depending on the material. The integral forming manufacturing process is, for example, injection molding, injection molding or compression molding.

[0030] Combination Figure 3 As shown, Figure 3 The diagram shows the bottom structure of the housing 1. A stepped groove 16 is provided at the bottom edge of the housing 1. The PCB board 2 is attached to the stepped groove 16, and the connection between the PCB board 2 and the stepped groove 16 is sealed with a sealant, such as epoxy resin.

[0031] The sample inlet channel 13 consists of an inner cavity 152 and two outer circulation channels 151. The two outer circulation channels 151 are symmetrically arranged on both sides of the inner cavity 152, and the outer port 154 of the outer circulation channel 151 is connected to the inner cavity 152. The inner port 153 of the outer circulation channel 151 is connected to the outlet 14 of the through groove 12.

[0032] An inner boss 155 is provided in the inner cavity 152. A smooth inclined surface 156 is provided between the inner boss 155 and the outer circulation channel 151. The inclined surface 156 is inclined in the direction that the top of the inner boss 155 is inclined towards the bottom surface of the outer circulation channel 151, and the height of the top of the inner boss 155 is greater than the height of the bottom surface of the outer circulation channel 151.

[0033] In this embodiment of the invention, the width of the inner boss 155 is greater than the width of the outer circulation channel 151, and the detection chip 3 is positioned directly opposite the inner boss 155. This allows the medium to enter the inner cavity 152 from the outer circulation channel 151 and reach the top of the inner boss 155 along the inclined surface 156, enabling the detection chip 3 to obtain more stable flow data.

[0034] The width ratio of the inner boss 155 width W1 to the outer circulation channel 151 width W2 is 4:1. In other embodiments, other ratios are also possible, as long as the width of the inner boss 155 is greater than the width of the outer circulation channel 151.

[0035] In this embodiment of the invention, an outer protrusion 157 is provided at intervals in the outer circulation channel 151. The top of the outer protrusion 157 is inclined toward the bottom surface of the outer circulation channel 151, and the height of the top of the outer protrusion 157 is greater than the height of the bottom surface of the outer circulation channel 151. The outer protrusion 157 cooperates with the inner protrusion 151 to greatly improve the smoothness of the medium flow and facilitate the acquisition of flow data.

[0036] The external circulation channel 151 has a vortex structure and includes multiple turning angles, the turning angles being 90°, and the turning angles being rounded. In this embodiment of the invention, the turning angle from the inner port 153 of the external circulation channel 151 to the outer port 154 is 450°, that is, when the single turning angle is 90°, the invention performs 5 consecutive turns.

[0037] Combination Figure 1 As shown, the detection chip 3 is bonded to the PCB board 2 with die-attach adhesive and electrically connected to the PCB board 2 by wire bonding. In other embodiments of the present invention, the PCB board 2 may also be provided with a receiving groove, the detection chip 3 is disposed in the receiving groove, and the top of the detection chip 3 is flush with the surface of the PCB board 2. When the medium is at a high flow rate, it will generate a high Reynolds number and Nusselt number, which will lead to flow separation. The separated flow will reduce the performance of the sensor. By making the top of the detection chip 3 flush with the surface of the PCB board 2, the influence of the detection chip 3 on the medium in the inner cavity 152 can be avoided.

[0038] The PCB board 2 is provided with flow guide grooves 20 at positions corresponding to the tube platform 11. The flow guide grooves 20 are connected to the flow channel port 153. The medium is introduced into the flow guide groove 20 from one of the tube platforms 11, then input into the flow channel cavity from the flow channel port 153, and output from the other tube platform 11.

[0039] To avoid interference from impurities in the medium, a positioning and mounting groove 22 is provided in the flow guide groove 20, and a filter part 4 is provided in the positioning and mounting groove 22. The filter part 4 is used to filter the medium input into the outlet 14 at the bottom of the channel 12.

[0040] Figure 4 See the schematic diagram of the filter section 4. Figure 4 As shown, in this embodiment of the invention, the filter section 4 includes a filter screen 42 and a support plate 41 surrounding the outside of the filter screen 42. The filter screen 42 is a perforated mesh structure, and the support plate 41 is disposed in the positioning mounting groove 22 to provide physical support. The shape of the filter section 4 matches the shape of the positioning mounting groove 22. For example, when the filter section 4 is circular, the shape of the positioning mounting groove 22 is also circular. In other embodiments, it can also be adjusted to other shapes according to actual application requirements, such as rectangles. This embodiment of the invention does not limit this.

[0041] In this embodiment of the invention, the filter section 4 can be arranged horizontally or vertically, and a suitable arrangement can be selected according to actual application requirements. When the filter section 4 is arranged vertically, compared to a horizontal arrangement, it can employ a larger area structure, thereby increasing the filtration area, improving the filtration effect, and enhancing the structural stability of the filter section 4. Specifically: When the filter section 4 is arranged horizontally, combined with Figure 1 and Figure 4 As shown, the positioning mounting groove 22 has a stepped structure and is horizontally positioned directly opposite the bottom outlet 14 of the through groove 12. The filter section 4 has a circular structure and is horizontally positioned within the positioning mounting groove 22. When the filter section 4 is vertically positioned, refer to... Figure 5-7 As shown, Figure 5 This is a schematic diagram of the positioning and mounting groove 22 when the filter section 4 is set vertically. Figure 6 This is a schematic diagram of the structure when the filter section 4 is installed vertically. Figure 7 The diagram shows the structure of the flow channel shell when the filter section 4 is vertically arranged. The positioning and mounting groove 22 is opened on both sides of the inner wall of the middle area of ​​the guide groove 20. The sample inlet flow channel 13 is provided with a filter mounting groove 17 corresponding to the position of the positioning and mounting groove 22. The filter section 4 has a rectangular structure and is embedded in the positioning and mounting groove 22 and the filter mounting groove 17.

[0042] In this embodiment of the invention, the pore size of the filter screen 42 is 80-500 mesh, and the pore size of the filter screen 42 can be determined according to the actual application scenario; for example, in the scenario where the filter screen 42 is applied to HVAC (Heating, Ventilation, Air Conditioning) damper control, it needs to filter PM10 level dust and fibers, and the pore size of the filter screen 42 can be 80-120 mesh; in the scenario where the filter screen 42 is applied to process control or gas metering, it needs to filter pipe rust, tar condensate, etc., and the pore size of the filter screen 42 can be 120-180 mesh; in the scenario where the filter screen 42 is applied to ventilators and anesthesia machines, it needs to filter droplet nuclei (≥5μm), dust, pathogens, etc., and the pore size of the filter screen 42 can be 200-300 mesh; When the filter 42 is used in an oxygen concentrator, it needs to filter zeolite dust and environmental particulate matter (≥3μm), and the pore size of the filter 42 can be 150-200 mesh. When the filter 42 is used in a gas analyzer, it needs to filter particles ≥2μm to protect the spectral / electrochemical sensor, and the pore size of the filter 42 can be 300-400 mesh. When the filter 42 is used in a leak detection device (helium detector, etc.), it needs to filter submicron particles (≥0.5μm), and the pore size of the filter 42 can be 400-500 mesh.

[0043] In this embodiment of the invention, the material of the filter screen 42 may be, for example, stainless steel / medical-grade titanium alloy woven mesh, polyethersulfone (PES) membrane composite stainless steel support mesh, nickel-based high-temperature alloy (Inconel 600) sintered filter element, etc., which can be selected according to actual application requirements, and this embodiment of the invention does not limit it.

[0044] The side of the PCB board 2 is also provided with a pin header 21, which forms a connection port for electrical connection with external active devices to transmit data.

[0045] In this embodiment of the invention, the side of the flow channel shell may also be provided with a plurality of connecting ears 15, which are used to connect with the external support structure to provide physical support.

[0046] The packaging structure based on a MEMS flow sensor described in this embodiment of the invention has the following advantages compared to the prior art: 1. The PCB board 2 is covered on the outside of the sample inlet channel 13 to form a flow channel cavity, and the detection chip 3 is placed in the flow channel cavity to realize the detection of the flow parameters of the medium in the flow channel cavity; 2. The flow channel shell is integrally molded, which greatly simplifies the production difficulty, improves the efficiency and product consistency during mass production, and the integral flow channel shell reduces the installation process of parts during assembly, thus reducing the installation difficulty. 3. An inner boss 155 is provided in the inner cavity 152, and a smooth inclined surface 156 is provided between the inner boss 155 and the outer circulation channel 151. The width of the inner boss 155 is greater than the width of the outer circulation channel 151, so that the medium passes through the inner boss 155 more smoothly. At the same time, an outer boss 157 is provided in the middle of the outer circulation channel 151. The outer boss 157 cooperates with the inner boss 151, so that the detection chip 3 can obtain more stable flow data. 4. The external circulation channel 151 has a vortex structure, and the turning angle from the inner port 153 of the external circulation channel 151 to the outer port 154 is 450°. Through multiple turns, laminar flow is facilitated, and the flow stability is improved. In addition, the vortex structure increases the channel utilization area while making the overall structure more compact and greatly reducing the space occupation. 5. The top of the detection chip 3 is flush with the surface of the PCB board 2. When the medium is flowing at high speed, it will generate a high Reynolds number and Nusselt number, which will lead to flow separation. The separated flow will reduce the performance of the sensor. By making the top of the detection chip 3 flush with the surface of the PCB board 2, the influence of the detection chip 3 on the medium in the inner cavity 152 can be avoided. 6. The guide channel 20 is provided with a positioning and mounting groove 22, and the positioning and mounting groove 22 is provided with a filter section 4, which can filter impurities (such as dust particles) in the medium.

[0047] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0048] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of the invention above. Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and it should be noted that the above embodiments are illustrative of the invention and not restrictive, and that alternative embodiments can be devised by those skilled in the art without departing from its scope.

Claims

1. A packaging structure based on a MEMS flow sensor, characterized in that, The packaging structure based on the MEMS flow sensor includes: a flow channel shell, a PCB board, and a detection chip; the flow channel shell includes a housing and two tube platforms, the bottom of the housing is provided with a sample inlet flow channel, the PCB board is covered on the outside of the sample inlet flow channel to form a flow channel cavity, the tube platforms are provided with a through groove, and the outlet at the bottom of the through groove communicates with the flow channel cavity; the detection chip is embedded on the PCB board, and the detection chip is located in the flow channel cavity.

2. The packaging structure based on the MEMS flow sensor according to claim 1, characterized in that: The flow channel shell is integrally molded; the integral molding process is injection molding, injection molding, or compression molding.

3. The packaging structure based on the MEMS flow sensor according to claim 1, characterized in that: A stepped groove is provided at the bottom edge of the housing, the PCB board is fitted into the stepped groove, and the connection between the PCB board and the stepped groove is sealed with sealant.

4. The packaging structure based on the MEMS flow sensor according to claim 1, characterized in that: The sample inlet channel consists of an inner cavity and two outer circulation channels. The two outer circulation channels are symmetrically arranged on both sides of the inner cavity, and the outer port of the outer circulation channel is connected to the inner cavity, while the inner port of the outer circulation channel is connected to the outlet of the through groove.

5. The packaging structure based on the MEMS flow sensor according to claim 4, characterized in that: An inner boss is provided in the inner cavity, and a smooth inclined surface is provided between the inner boss and the outer circulation channel. The inclined surface is inclined in the direction that the top of the inner boss is inclined towards the bottom surface of the outer circulation channel, and the height of the top of the inner boss is greater than the height of the bottom surface of the outer circulation channel. The width of the inner boss is greater than the width of the outer circulation channel, and the detection chip is positioned directly opposite the inner boss. The width ratio of the inner boss width W1 to the outer circulation channel width W2 is 4:

1.

6. The packaging structure based on the MEMS flow sensor according to claim 5, characterized in that: The external circulation channel is provided with external protrusions at intervals. The top height of the external protrusions is greater than the bottom height of the external circulation channel, and the top of the external protrusions extends toward the bottom of the external circulation channel.

7. The packaging structure based on the MEMS flow sensor according to claim 5, characterized in that: The external circulation channel has a vortex structure with multiple turning angles, each turning angle being 90°, and the turning angles are rounded. The turning angle from the inner port of the external circulation channel to the outer port is 450°.

8. The packaging structure based on the MEMS flow sensor according to claim 1, characterized in that: The detection chip is bonded to the PCB board with die bond adhesive and electrically connected to the PCB board by wire bonding; the PCB board is also provided with a receiving groove, the detection chip is placed in the receiving groove, and the top of the detection chip is flush with the surface of the PCB board.

9. The packaging structure based on a MEMS flow sensor according to claim 8, characterized in that: The PCB board is provided with flow guide grooves corresponding to the positions of the tube platform. The flow guide grooves are connected to the flow channel ports. The flow guide grooves are provided with positioning and mounting grooves, and the positioning and mounting grooves are provided with filter parts.

10. The packaging structure based on the MEMS flow sensor according to claim 9, characterized in that: The filter section is configured either horizontally or vertically. The filter section includes a filter screen and a support plate surrounding the outside of the filter screen. The filter screen is a perforated mesh structure. The support plate is disposed in the positioning and mounting groove. The pore size of the filter screen is 80~500 mesh. The shape of the filter section matches the shape of the positioning and mounting groove. The filter section is circular or rectangular. When the filter section is horizontally positioned, the positioning and mounting groove is a stepped structure and is horizontally positioned opposite the bottom outlet of the channel. The filter section is circular. When the filter section is vertically positioned, the positioning and mounting groove is formed on opposite sides of the inner wall of the middle area of ​​the guide channel. The sample inlet channel has a filter mounting groove corresponding to the position of the positioning and mounting groove. The filter section is rectangular and is embedded in the positioning and mounting groove and the filter mounting groove.

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