A barometric MEMS sensor

Abstract

The application belongs to the technical field of semiconductors, and particularly relates to a gas pressure MEMS sensor, which comprises a base and a first cavity penetrating the thickness of the base; an induction film and a fixed plate are arranged in a laminated mode on one side of the base, the fixed plate is arranged below the induction film and is arranged in a spaced mode to form a second cavity; a plurality of first through holes are arranged on the side of the base close to the fixed plate, the inner wall of the first through hole is provided with a second through hole in communication with the second cavity, the end of the first through hole is provided with a liquid collecting sink, and the liquid collecting sink is connected in communication to form an annular groove in the base; according to the scheme, the first through hole is arranged on the periphery of the orthographic projection of the first cavity on the fixed plate, the hole is not directly arranged on the fixed plate, and the liquid is prevented from directly entering the second cavity from the hole to affect the normal work between the fixed plate and the induction film; the end of the first through hole is arranged to be connected in communication to form an annular groove in the base, small liquid entering from the first through hole is buffered and collected in the annular groove, and the liquid is prevented from entering the second cavity.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more particularly to a barometric pressure MEMS sensor. Background Technology

[0002] Existing MEMS chips all come directly from the acoustics industry. Sensors used in electronic cigarettes and acoustic applications have different structural requirements due to their different principles, and this approach currently has certain drawbacks. The principle of MEMS airflow sensors is to convert the change in distance between the upper fixed plate and the lower sensing diaphragm into an airflow pressure output. That is, the capacitance value is changed by the change in the position of the sensing diaphragm, and finally the airflow pressure is detected.

[0003] During the manufacturing process of existing electronic cigarette MEMS sensors, the compressed gas from the central air conditioning and packaging equipment in the workshop inevitably produces a slight amount of emulsified oily liquid. This emulsified liquid always contaminates the sensing membrane to a certain extent. More seriously, some products cannot be detected or intercepted by automated testing equipment, leading to fatal defects such as self-starting or intermittent continuous output during end-customer applications. Specifically, this manifests in the following ways:

[0004] 1. The packaging process is easily damaged: MEMS bare dies are easily affected by external liquids (oil, water vapor, etc.) during the packaging process. This can easily cause liquids in the production process (such as oil inside the compressed gas of the packaging equipment, or compressed emulsified water vapor brought by the central air conditioning in the workshop) to seep through the holes on the fixed electrode plate, causing the fixed electrode plate and the sensing diaphragm to stick together, resulting in functional failure.

[0005] 2. Risks in Post-Processing: The application of MEMS technology in e-cigarettes involves complex circuit design and microelectronic components. Due to the tiny size of MEMS devices and their dense internal circuit wiring, improper process control during manufacturing can lead to the MEMS being susceptible to external environmental influences (liquids, rosin, solder beads, etc.) during post-processing. This can cause minute amounts of liquids, rosin, solder beads, etc., to seep through the mesh holes of the MEMS chip's fixing plate and adhere to the underlying sensing diaphragm, resulting in functional failure. This can not only damage the e-cigarette device but, in severe cases, may also cause battery overheating, combustion, or even explosion, threatening the user's personal safety.

[0006] 3. As attached Figure 9 As shown, existing MEMS products have many pores on the fixed electrode plate, which are located directly above the sensing membrane. This makes them susceptible to external environmental influences, which can easily lead to functional failure. The thickness of the fixed electrode plate is approximately 1-2 μm. When the air pressure exceeds 90 kPa, the sensing membrane is easily damaged. The sensing membrane exhibits slight vibrations under slight airflow pressure, which can lead to the mistransmission of airflow signals to the ASIC in applications.

[0007] Therefore, this is a technical problem that urgently needs to be solved. Summary of the Invention

[0008] This invention provides a pressure MEMS sensor that solves the shortcomings of existing technologies, such as liquid entering through the air holes of the fixed electrode plate, affecting the normal operation of the electrode plate and the sensing membrane, the sensing membrane being easily damaged when the air pressure is greater than 90 kPa, and the sensing membrane exhibiting slight vibration under slight air pressure, resulting in false signal transmission.

[0009] The present invention provides the following technical solution: a pressure MEMS sensor, comprising a base, a sensing film, and a fixed electrode plate. The base has a first cavity penetrating the thickness of the base. The sensing film and the fixed electrode plate are stacked on one side of the base, with the fixed electrode plate located below the sensing film and spaced apart, so that a second cavity is formed between the fixed electrode plate and the sensing film. The side of the base near the fixed electrode plate has a plurality of first through holes, the inner wall of the first through holes has a second through hole communicating with the second cavity, and the end of the first through holes has a liquid collection trough, which is connected in the base to form an annular groove.

[0010] Preferably, the first cavity is non-porous at the orthographic projection of the fixed electrode plate, and the first through hole is set on the base wall to avoid damaging the structure of the fixed electrode plate and the first cavity. This non-porous fixed electrode plate directly prevents liquid from entering the second cavity. Several first through holes are evenly spaced along the base wall. The channel of the first through hole has a second through hole that communicates with the second cavity, and an annular groove is set at the end of the channel. First, the air intake is dispersed through several first through holes. After dispersion, the airflow velocity in the first through holes is reduced, forming the first filtration. At the same time, the annular groove at the end reduces the pressure of the liquid entering the liquid collection tank with the airflow from the channel, which in turn causes the liquid to settle in the liquid collection tank, preventing the liquid from entering the second cavity with the airflow through the second through hole to form the second layer of filtration. The multi-stage filtration method ensures that the environment in the second cavity is not affected by fine liquids.

[0011] Furthermore, the cross-section of the annular groove is one of O-shape, D-shape, cone shape or trapezoid.

[0012] Furthermore, an arc-shaped radius (R-angle) is provided at the connection between the first and second through holes. The arc-shaped radius serves to reduce pressure, allowing liquid to deposit within the annular groove and reducing the amount of liquid entering the second through hole.

[0013] Furthermore, the fixed electrode plate has a raised structure on the side near the sensing film, the height of the raised structure is 0.3μm-0.7μm and the diameter is 0.1μm-1μm; the raised structure is made of a smooth insulating material.

[0014] Preferably, the height of the raised structure is 0.4μm-0.6μm and the diameter is 0.2μm-0.8μm. The raised structure is distributed at a certain interval on the upper surface of the fixed electrode plate. The interval is a fixed distance or can be freely set according to the model. Its characteristics are that it is a smooth insulating material made of Si. With its good insulation and smoothness, it serves as a contact point to prevent the electroplated conductive thin layer on the fixed electrode plate from adhering to the sensing film.

[0015] Even better, the height of the protrusion structure is 0.5 μm and the diameter is 0.6 μm.

[0016] Furthermore, the sensing membrane is provided with vent holes with a diameter of 1μm-6μm.

[0017] Preferably, the diameter of the vent hole is 2μm-5μm, and the vent hole is located at the center of the sensing membrane. The design of the vent hole ensures that the air pressure on both sides of the sensing membrane is balanced when the product is in a high-temperature environment, which extends the service life of the sensing membrane and avoids the product from shaking under slight airflow. It also prevents the sensing membrane from being unable to return to its original state after being heated and deformed in a sealed environment.

[0018] Even better, the diameter of the vent hole is 3μm or 4μm.

[0019] Furthermore, the first through hole is a circular hole or a square hole, and the channel of the first through hole is arc-shaped, straight-shaped, or right-angled.

[0020] Furthermore, the first through hole opening is set on the lower end face of the base, and is evenly spaced along the outer edge of the base.

[0021] Furthermore, the first through hole is located on the side of the lower end of the base and is offset from the second through hole.

[0022] Furthermore, a reinforcing layer is provided on both sides of the fixed electrode plate. The reinforcing layer on the side away from the sensing film protrudes outward and is the lower fixing layer. The reinforcing layer on the other side is an insulating layer and is provided on the side close to the sensing film. This layer is the upper fixing layer.

[0023] Preferably, the upper fixing layer is used to reinforce the upper surface of the fixed electrode plate, i.e., vertical reinforcement, and the lower fixing layer is used to reinforce the lower edge of the fixed electrode plate, i.e. horizontal reinforcement. The thickness of the upper fixing layer is 0.1μm-1μm. The two fixing layers and the fixed electrode plate work together to enhance the mechanical properties between the fixed electrode plate 01a and the base 14 from different levels, ensuring that the sensor can still maintain structural stability and resist external physical impacts under complex working conditions.

[0024] Even better, the thickness of the upper fixing layer is 0.2μm, 0.4μm, 0.5μm, 0.6μm or 0.8μm; the upper fixing layer is an insulating layer to prevent current leakage and ensure safety.

[0025] The lower fixing layer protrudes downwards to prevent the nozzle from having burrs that could damage the fixing plate during chip removal. The protrusion creates a certain distance between the fixing plate and the outer surface of the lower fixing layer, thereby reducing the significant damage to the fixing plate caused by burrs on the nozzle surface during subsequent production and preventing surface defects such as mechanical scratches and microcracks from appearing on the surface of the fixing plate.

[0026] The thickness of the lower fixing layer is 0.2μm-2μm, and it is made of silicon oxide (SiO2), silicon nitride (Si3N4), or other polymer materials. It has anti-conductive and anti-electrical interference properties. A coating is formed on the surface of the lower fixing layer to isolate electrical properties and provide anti-interference. Preferably, the thickness of the lower fixing layer is 0.4μm, 0.5μm, 0.8μm, 1.0μm, 1.2μm, 1.5μm, or 1.8μm.

[0027] Furthermore, the term also includes the grassroots level, which includes:

[0028] The first structural layer is a transitional structural layer with a thickness of 0.2μm-1μm, which connects the upper second structural layer and the lower fixed electrode plate;

[0029] The second structural layer has a thickness of 1μm-1.5μm, and a second through-hole is formed on this layer;

[0030] The third structural layer, located below the sensing film, is a buffer physical layer to prevent external interference to the sensing film; it has an arc-shaped R-angle near the first through-hole, and the third structural layer is located above the second structural layer;

[0031] The fourth structural layer is located above the third structural layer. The inner side of the fourth structural layer is provided with a mounting platform for setting the sensing film, so that there is a certain distance between the sensing film and the base. An annular groove is provided in the fourth structural layer.

[0032] Preferably, the first structural layer is a transitional structural layer with a thickness of 0.3μm-0.8μm. The first structural layer is disposed between the upper second structural layer and the lower upper fixed layer. The lateral area of ​​the first structural layer accounts for approximately 20%, and it is made of Si material, which has good flexibility and excellent mechanical properties. As a transitional structure, it ensures a smooth transition and good bonding between different layers and reduces stress concentration. The first structural layer also includes a support portion connected to the first structural layer for filling or supporting, and plays a role in buffering and shock absorption. A first air guide hole connected to the first through hole is provided on the first structural layer.

[0033] The second structural layer, with a thickness of 1.1μm-1.4μm, protects and fixes the internal structure. The lateral area of ​​the second structural layer is less than 20%, and it is made of Si material, which has high mechanical strength and good protective performance. The second structural layer is provided with a second air guide hole that communicates with the first through hole. A second through hole is provided on the inner wall of the second air guide hole. The second structural layer protects and fixes the internal structure. The channel, the second through hole, and the inner wall of the second structural layer are all smooth surfaces.

[0034] The third structural layer, a buffer physical layer located below the sensing membrane, prevents external interference with the sensing membrane and serves to fix it in place. It has an arc-shaped radius (R-angle) near the first through hole. The third structural layer also has a third air guide hole that communicates with the first through hole. The third air guide hole has an arc-shaped radius (R-angle) on the side near the inlet of the second through hole, and the third air guide hole is perpendicular to the second through hole. This ensures that external liquids cannot enter the second cavity through the second through hole.

[0035] The fourth structural layer has a thickness of 5μm-10μm. An mounting platform is provided on the inner side of this layer. The mounting platform is used to mount the sensing membrane and to create a certain distance between the sensing membrane and the base, thus preventing interference. After mounting, the sensing membrane is on the same plane as the lower surface of the fourth structural layer. An annular groove communicating with the channel and the first through hole is provided on the fourth structural layer. The cross-section of the liquid collection groove is O-shaped or D-shaped. Preferably, the thickness of the fourth structural layer is 6μm, 7μm, 8μm, or 9μm; the depth of the annular groove does not exceed 5μm.

[0036] In this embodiment, the first cavity is designed to raise the height of the entire sensor, increasing the space for the sensing membrane to sense the airflow and preventing excessive air pressure in the space from causing the sensing membrane to fail to return to its original position quickly.

[0037] In addition, a first metal pad and a second metal pad are provided on the base. The first metal pad is used to guide the electrical properties of the sensing film to the surface layer; the second metal pad is used to guide the electrical properties of the fixed electrode plate to the surface layer; both the first metal pad and the second metal pad are located at the corners of the base.

[0038] It should be noted that the liquid in this invention refers to liquids generated during the production process, such as oil inside the compressed gas of the packaging equipment, compressed emulsified water vapor carried by the central air conditioning in the workshop, fine liquids generated during the back-end processing of the product, rosin, solder beads, etc., and small droplets that affect the packaging or normal operation of the fixed electrode plate and sensing film due to oil leakage in different usage scenarios after the finished product is assembled.

[0039] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit the invention.

[0040] The present invention has the following beneficial effects:

[0041] 1. A first through-hole is provided around the orthographic projection of the first cavity onto the fixed electrode plate, avoiding direct opening on the fixed electrode plate. This prevents impurities such as liquids from directly entering the second cavity through the hole and affecting the normal operation between the fixed electrode plate and the sensing membrane. The holeless design on the fixed electrode plate optimizes the tolerance of the facing area caused by the opening, making the fixed electrode plate closer to a "uniform conductive plane," ensuring accurate facing area and stable dielectric environment. The holeless fixed electrode plate reduces leakage current and avoids capacitance fluctuations, directly ensuring the charge average and voltage division stability of the backplate voltage. In addition, a first through-hole communicating with the second cavity is provided on the periphery, and an annular liquid collection trough is provided at the end of the first through-hole. The liquid collection trough is internally connected to form an annular groove, which buffers and collects the fine liquid entering from the first through-hole in the annular groove, preventing it from entering the second cavity. Furthermore, the first through-hole is provided in several quantities to disperse the airflow entering the first through-hole, reducing the airflow velocity in a single hole, thereby improving liquid deposition.

[0042] 2. The vent is located at the center of the sensing membrane. The design of the vent ensures that the air pressure on both sides of the sensing membrane can be balanced even in high-temperature environments, thus extending the service life of the sensing membrane. It also prevents the product from shaking under slight airflow. In addition, it prevents the sensing membrane from being unable to return to its original state after being heated and deformed in a sealed environment.

[0043] The vent hole is connected to the second cavity and the first through hole to ensure that the air pressure of the second cavity is balanced with the outside air, and to prevent the sensing membrane from being damaged when the pressure of the second cavity or the first cavity increases.

[0044] 3. By setting an insulating protrusion structure on the upper surface of the fixed electrode plate, the influence of external air pressure on the sensing film or fixed electrode plate is avoided, which would cause the fixed electrode plate to be close to or bonded to the sensing film and conduct electricity, resulting in the failure of the sensing film.

[0045] 4. By setting reinforcement layers on the upper and lower layers of the fixed electrode plate, the pressure bearing capacity of the fixed electrode plate is improved from different directions. At the same time, the lower fixing layer can avoid mechanical damage to the fixed electrode plate by the suction nozzle shroud, thereby improving the service life of the fixed electrode plate.

[0046] 5. By setting an arc-shaped R-angle at the connection between the second through hole and the channel, the liquid is deposited, the airflow pressure in the channel is reduced at this point, thereby preventing the liquid from entering the second cavity from the second through hole and reducing the accumulation of liquid at the second through hole.

[0047] 6. This invention is not limited to applications in the field of electronic cigarette sensors, but can also be applied to MEMS chip special structure packaging and airflow pressure detection devices. Attached Figure Description

[0048] Figure 1 This is one of the cross-sectional views of a barometric pressure MEMS sensor according to an embodiment of this application;

[0049] Figure 2 for Figure 1 A schematic diagram of the matrix structure;

[0050] Figure 3 This is a schematic diagram of the second through-hole distribution of a pressure MEMS sensor according to an embodiment of this application;

[0051] Figure 4 This is one of the schematic diagrams showing the annular groove arrangement of a pressure MEMS sensor according to an embodiment of this application;

[0052] Figure 5 This is an enlarged schematic diagram of the arc-shaped radius (R-angle) of a pressure MEMS sensor according to an embodiment of this application;

[0053] Figure 6 This is a top view of the first structural layer of a barometric pressure MEMS sensor according to an embodiment of this application;

[0054] Figure 7 A top view of a pressure MEMS sensor according to an embodiment of the application;

[0055] Figure 8 A cross-sectional view of a pressure MEMS sensor according to an embodiment of the application;

[0056] Figure 9 This is a cross-sectional view of an existing technology structure;

[0057] Figure 10 This is one of the structural cross-sectional views of a barometric pressure MEMS sensor according to an embodiment of this application;

[0058] Figure 11 This is a second cross-sectional view of the structure of a barometric pressure MEMS sensor according to an embodiment of this application;

[0059] Figure 12 This is a second schematic diagram showing the annular groove configuration of a pressure MEMS sensor according to an embodiment of this application;

[0060] Figure 13 This is the third schematic diagram of the annular groove arrangement of a pressure MEMS sensor according to an embodiment of this application;

[0061] 01. Base layer; 01a. Fixed electrode plate; 01b. Upper fixed layer; 01c. Lower fixed layer; 02. First through hole; 02a. Longitudinal through hole; 02b. Transverse through hole; 03. First structural layer; 03a. Support part; 04. First vent hole; 05. Protruding structure; 06. Second structural layer; 07. Second vent hole; 08. Second through hole; 09. Third structural layer; 09a. Arc-shaped R-angle; 10. Third vent hole; 11. Sensing membrane; 12. Vent hole; 13. Fourth structural layer; 13a. Annular groove; 14. Base; 15. First cavity; 16. First metal pad; 17. Second metal pad; 18. Second cavity. Detailed Implementation

[0062] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0063] Example 1, refer to Figures 1-8 A pressure MEMS sensor includes a base 14, a sensing film 11, and a fixed electrode plate 01a. The thickness of the base 14 is 200μm-400μm, and in this embodiment, the thickness of the base 14 is 400μm. The base 14 also includes a first cavity 15 that penetrates the thickness of the base 14. The sensing film 11 and the conductive fixed electrode plate 01a are stacked on one side of the base 14. The thickness of the sensing film 11 is 0.5μm, and the fixed electrode plate 01a is located below the sensing film 11. The plates are spaced apart to form a second cavity 18 between the fixed electrode plate 01a and the sensing membrane 11. The base 14 is provided with a plurality of first through holes 02 on the side near the fixed electrode plate 01a. The opening of the first through holes 02 is located on the lower end face of the base 14. The inner wall of the first through holes 02 is provided with a second through hole 08 that communicates with the second cavity 18. The end of the first through holes 02 is provided with a liquid collection trough. The liquid collection trough is connected in the base 14 to form an annular groove 13a with a depth of 4μm.

[0064] Preferably, the thickness of the fixed electrode plate 01a is 4μm. The first cavity 15 is non-porous at its orthogonal projection onto the fixed electrode plate 01a. The first through hole 02 is disposed on the wall of the base 14, thereby avoiding damage to the structure in which the fixed electrode plate 01a and the first cavity 15 are correspondingly disposed. That is, the fixed electrode plate 01a is non-porous at the location where the fixed electrode plate 01a and the first cavity 15 are correspondingly disposed. This arrangement can directly prevent liquid from entering the second cavity 18. A plurality of first through holes 02 are equally spaced along the wall of the base 14. The channel of the first through hole 02 is extended longitudinally along the thickness direction of the base 14, and the channel is provided with a... The second cavity 18 is connected to the second through hole 08, and an annular groove 13a is provided at the end of the channel. First, the incoming air is dispersed through several first through holes 02. After dispersion, the flow velocity of the airflow in a single first through hole 02 is reduced, forming the first filtration. At the same time, the annular groove 13a is provided at the end of the channel. The liquid entering the annular groove 13a from the channel with the airflow will have its pressure reduced, which will cause the liquid to settle in the liquid collection trough, preventing the liquid from entering the second cavity 18 with the airflow through the second through hole 08 to form the second layer of filtration. The multi-stage filtration method ensures that the environment inside the second cavity 18 is not affected by fine liquids.

[0065] In this embodiment, the cross-section of the annular groove 13a is O-shaped, which reduces the pressure and collects liquid for the airflow entering the annular groove 13a from the first through hole 02, thereby reducing the amount of liquid entering the second cavity 18 from the second through hole 08. An arc-shaped R-angle 09a is provided at the connection between the first through hole 02 and the second through hole 08. The arc-shaped R-angle 09a reduces the pressure and promotes the deposition of liquid in the annular groove 13a, preventing liquid from accumulating at the second through hole 08 and further reducing the amount of liquid entering the second through hole 08.

[0066] In this embodiment, a raised structure 05 is provided on the side of the fixed electrode plate 01a near the sensing membrane 11. The raised structure 05 has a height of 0.5 μm and a diameter of 0.6 μm. The raised structure 05 is made of a smooth insulating material. A vent hole 12 with a diameter of 3 μm is provided on the sensing membrane 11.

[0067] The base 14 is also provided with a first metal pad 16 and a second metal pad 17. The first metal pad 16 is used to guide the electrical properties of the sensing film 11 to the surface layer; the second metal pad 17 is used to guide the electrical properties of the fixed electrode plate 01a to the surface layer; the first metal pad 16 and the second metal pad 17 are both located at the corners of the base 14.

[0068] Example 2 differs from Example 1 in that the thickness of the base 14 is 220 μm, the thickness of the sensing membrane 11 is 0.2 μm, and the first through hole 02 is inclined along the thickness direction of the base 14, so that the first through hole 02 forms a certain inclination angle with the annular groove 13a. The airflow rotates in the annular groove 13a, causing the liquid entering the annular groove 13a from the first through hole 02 to quickly deposit in the annular groove 13a under the action of centrifugal force, reducing the risk of liquid entering the second through hole 08; Figure 13 As shown, the cross-section of the annular groove 13a is D-shaped, and the depth of the annular groove 13a is 2μm.

[0069] An arc-shaped R-angle 09a is provided at the connection between the inner wall of the channel and the second through hole 08. The arc-shaped R-angle 09a is set on the side close to the annular groove 13a. The arc-shaped R-angle 09a plays a role in reducing pressure, which promotes the deposition of liquid in the annular groove 13a and further reduces the amount of liquid entering the second through hole 08.

[0070] In this embodiment, the thickness of the fixed electrode plate 01a is 5 μm. A raised structure 05 is provided on the side of the fixed electrode plate 01a near the sensing membrane 11. The raised structure 05 has a height of 0.4 μm and a diameter of 0.2 μm, and is hemispherical. The raised structure 05 is made of a smooth insulating material and is distributed in a matrix on the fixed electrode plate 01a. A vent hole 12 with a diameter of 2 μm is provided on the sensing membrane 11. The vent hole 12 is located at the center of the sensing membrane 11. The vent hole 12 ensures that the air pressure on both sides of the sensing membrane 11 is balanced even in high-temperature environments, extending the service life of the sensing membrane 11. It also prevents the product from shaking under slight airflow and prevents the sensing membrane 11 from becoming deformed due to heat in a sealed environment and unable to return to its original state.

[0071] Example 3 differs from Example 1 in that: the first through hole 02 is set deep along the thickness direction of the base 14, the first through hole 02 is a circular first through hole 02, and the channel of the first through hole 02 is straight; the end of the first through hole 02 is connected to the annular groove 13a, and the cross section of the annular groove 13a is conical. This structure facilitates the deposition of liquid in the gas flow in the annular groove 13a.

[0072] In this embodiment, the thickness of the fixed electrode plate 01a is 6 μm. A protruding structure 05 is provided on the side of the fixed electrode plate 01a near the sensing film 11. The height of the protruding structure 05 is 0.6 μm and the diameter is 0.8 μm. The protruding structure 05 is a cylindrical structure. The protruding structure 05 is made of a smooth insulating material. The protruding structures 05 are randomly distributed on the fixed electrode plate 01a. The protruding structures 05, with their good insulation and smoothness, serve as contacts to prevent the electroplated conductive thin layer on the fixed electrode plate 01a from adhering to the sensing film 11.

[0073] The sensing membrane 11 is provided with a vent hole 12 with a diameter of 5μm. The vent hole 12 is located on one side of the central axis of the sensing membrane 11 to ensure the sensitivity of the sensing membrane 11 to air pressure and to prevent the sensing membrane 11 from being unable to return to its original state after being heated and deformed in a sealed environment.

[0074] In this embodiment, both the upper and lower layers of the fixed electrode plate 01a are provided with reinforcing layers. The reinforcing layers include a lower fixing layer 01c and an upper fixing layer 01b. The lower fixing layer 01c protrudes outward, and the upper fixing layer 01b is an insulating layer located near the sensing film 11. Preferably, the upper fixing layer 01b is used to reinforce the upper surface of the fixed electrode plate 01a, i.e., vertical reinforcement, while the lower fixing layer 01c is used to reinforce the lower edge of the fixed electrode plate 01a, i.e., horizontal reinforcement. The thickness of the upper fixing layer 01b is 0.3 μm. The two fixing layers, together with the fixed electrode plate 01a, enhance the mechanical properties between the fixed electrode plate 01a and the base 14 from different levels, ensuring that the sensor can maintain structural stability and resist external physical impacts under complex working conditions.

[0075] Even better, the upper fixing layer 01b is an insulating layer to prevent current leakage and ensure safety.

[0076] The lower fixing layer 01c protrudes downwards to prevent the nozzle burrs from posing a risk to the fixing plate 01a when the nozzle picks up the chip. The protrusion creates a certain distance between the fixing plate 01a and the outer surface of the lower fixing layer 01c, thereby reducing the significant damage to the fixing plate 01a caused by the burrs on the nozzle surface during subsequent production processes, and preventing surface defects such as mechanical scratches and microcracks on the surface of the fixing plate 01a. The lower fixing layer 01c has a thickness of 0.5μm and is made of silicon oxide (SiO2), silicon nitride (Si3N4) or other polymer materials, which has anti-conductivity and anti-interference properties. The surface of the lower fixing layer 01c is coated with a coating that is used to isolate electrical properties and provide anti-interference.

[0077] Example 4 differs from Example 3 in that: (Refer to...) Figure 10 The thickness of the base 14 is 300 μm, the thickness of the sensing film 11 is 0.5 μm, the opening of the first through hole 02 is set on the side of the lower end of the base 14, the channel of the first through hole 02 is right-angled, the end of the first through hole 02 is connected to the annular groove 13a, the first through hole 02 and the second through hole 08 are staggered, the second through hole 08 is set on the inner wall of the vertical channel of the first through hole 02 to avoid the first through hole 02 and the second through hole 08 being located on the same horizontal straight line; the cross section of the annular groove 13a is trapezoidal, this structure facilitates the deposition of liquid in the airflow in the annular groove 13a, and the depth of the annular groove 13a is 3 μm.

[0078] In this embodiment, both the upper and lower layers of the fixed electrode plate 01a are provided with reinforcing layers. The reinforcing layers include a lower fixing layer 01c and an upper fixing layer 01b. The lower fixing layer 01c protrudes outward, and the upper fixing layer 01b is an insulating layer and is located on the side close to the sensing film 11 to prevent current leakage and ensure safety.

[0079] Preferably, the upper fixing layer 01b is used to reinforce the upper surface of the fixed electrode plate 01a, i.e., vertical reinforcement, and the lower fixing layer 01c is used to reinforce the lower edge of the fixed electrode plate 01a, i.e. horizontal reinforcement. The thickness of the upper fixing layer 01b is 0.4μm and the thickness of the lower fixing layer 01c is 1.2μm. The two fixing layers and the fixed electrode plate 01a work together to enhance the mechanical properties between the fixed electrode plate 01a and the base 14 from different levels, ensuring that the sensor can still maintain structural stability and resist external physical impacts under complex working conditions.

[0080] The lower fixing layer 01c protrudes downwards to prevent the nozzle shroud from posing a risk to the fixing plate 01a when the nozzle removes the chip, and to prevent surface defects such as mechanical scratches and microcracks from appearing on the surface of the fixing plate 01a. The lower fixing layer 01c is made of silicon oxide (SiO2), silicon nitride (Si3N4) or other polymer materials, and has anti-conductivity and anti-interference properties. The surface of the lower fixing layer 01c is coated to isolate electrical properties and provide anti-interference.

[0081] Example 5 differs from Example 1 in that: the lower surface of the base 14 near the fixed electrode plate 01a is provided with several square first through holes 02. The first through holes 02 are evenly spaced along the outer edge of the base 14 and are arranged in a straight line along the thickness direction of the base 14. The inner wall of the channel of the first through hole 02 is provided with a second through hole 08 communicating with the second cavity 18. A liquid collection trough is provided at the end of the first through hole 02, and the liquid collection trough is connected within the base 14 to form an annular groove 13a. Figure 12 As shown, the cross-section of the annular groove 13a is O-shaped.

[0082] In this embodiment, a raised structure 05 is provided on the side of the fixed electrode plate 01a near the sensing film 11. The raised structures 05 are distributed in concentric circles at equal intervals on the fixed electrode plate 01a. The height of the raised structure 05 is 0.5 μm and the diameter is 0.5 μm. The raised structure 05 is a smooth insulating material made of Si. With its good insulation and smoothness, it serves as a contact point to prevent the electroplated conductive thin layer on the fixed electrode plate 01a from adhering to the sensing film 11.

[0083] In this embodiment, the sensing membrane 11 is provided with a vent hole 12, which has a diameter of 4μm. The vent hole 12 is located at the center of the sensing membrane 11. The vent hole 12 enables the product to balance the air pressure on the upper and lower surfaces of the sensing membrane 11 even in high-temperature environments, thereby extending the service life of the sensing membrane 11. It also prevents the product from shaking under slight airflow and prevents the sensing membrane 11 from being unable to return to its original state after being deformed by heat in a sealed environment.

[0084] In this embodiment, both the upper and lower layers of the fixed electrode plate 01a are provided with reinforcing layers. The reinforcing layers include a lower fixing layer 01c and an upper fixing layer 01b. The lower fixing layer 01c protrudes outward. The upper fixing layer 01b is an insulating layer and is located on the side close to the sensing film 11 to prevent current leakage and ensure safety.

[0085] Preferably, the upper fixing layer 01b is used to reinforce the upper surface of the fixed electrode plate 01a, i.e., vertical reinforcement, and the lower fixing layer 01c is used to reinforce the lower edge of the fixed electrode plate 01a, i.e. horizontal reinforcement. The thickness of the upper fixing layer 01b is 0.8μm and the thickness of the lower fixing layer 01c is 1.8μm. The two fixing layers and the fixed electrode plate 01a work together to enhance the mechanical properties between the fixed electrode plate 01a and the base 14 from different levels, ensuring that the sensor can still maintain structural stability and resist external physical impacts under complex working conditions.

[0086] Even better, the lower fixing layer 01c protrudes downwards to avoid the risk of the nozzle burrs on the fixing plate 01a when the nozzle picks up the chip. The protrusion creates a certain distance between the fixing plate 01a and the outer surface of the lower fixing layer 01c, thereby reducing the significant damage to the fixing plate 01a caused by the burrs on the nozzle surface during subsequent production, and avoiding surface defects such as mechanical scratches and microcracks on the surface of the fixing plate 01a. The lower fixing layer 01c is made of silicon oxide (SiO2), silicon nitride (Si3N4) or other polymer materials, which have anti-conductive and anti-electrical interference properties. The surface of the lower fixing layer 01c is coated to isolate electrical properties and provide anti-interference.

[0087] In this embodiment, the chip structure further includes a base layer 01, which includes:

[0088] The first structural layer 03 is a transitional structural layer with a thickness of 0.5 μm. A second structural layer 06 is disposed above the first structural layer 03, and an upper fixing layer 01b is disposed below the first structural layer 03. The first structural layer 03 has a lateral area ratio of 20%, is made of Si material, and has good flexibility and excellent mechanical properties. As a transitional structure, it ensures a smooth transition and good bonding between different layers and reduces stress concentration. The first structural layer 03 also includes a support part 03a connected to the first structural layer 03 for filling or supporting, and plays a role in buffering and shock absorption. A first air guide hole 04 connected to the first through hole 02 is provided on the first structural layer 03.

[0089] The second structural layer 06, with a thickness of 1.1 μm, protects and fixes the internal structure. It has a lateral area ratio of 19% and is made of Si material, which has high mechanical strength and good protective performance. The second structural layer 06 is provided with a second air guide hole 07 that communicates with the first through hole 02. A second through hole 08 is provided on the inner wall of the second air guide hole 07. The second structural layer 06 protects and fixes the internal structure. The channel, the second through hole 08, and the inner wall of the second structural layer 06 are all smooth surfaces.

[0090] The third structural layer 09 is a buffer physical layer located below the sensing membrane 11, with a thickness of 0.5 μm. It prevents external interference with the sensing membrane 11 and plays a role in fixing the sensing membrane 11. An arc-shaped R-angle 09a is provided near the first through hole 02. The third structural layer 09 is also provided with a third air guide hole 10 that communicates with the first through hole 02. The third air guide hole 10 has an arc-shaped R-angle 09a on the side near the inlet of the second through hole 08. The third air guide hole 10 is perpendicular to the second through hole 08 to ensure that external liquids cannot enter the second cavity 18 through the second through hole 08.

[0091] The fourth structural layer 13 has a thickness of 6μm. An installation platform is provided on the inner side of this structural layer for setting the sensing membrane 11 and isolating the sensing membrane 11 from the base 14 by a certain distance, which plays a role in anti-interference. After the sensing membrane 11 is installed on the installation platform, it is on the same plane as the lower surface of the fourth structural layer 13. An annular groove 13a is provided on the fourth structural layer 13, which communicates with the channel and the first through hole 02. The depth of the annular groove 13a is 2μm.

[0092] The first cavity 15 is designed to raise the height of the entire sensor, increase the space for the sensing membrane 11 to sense the airflow, and prevent the sensing membrane 11 from failing to return to its original position quickly due to excessive air pressure in the space.

[0093] The first through hole 02 passes sequentially through the lower fixing layer 01c, the fixing electrode plate 01a, the upper fixing layer 01b, the first structural layer 03, the second structural layer 06, and the third structural layer 09, and communicates with the annular groove 13a in the fourth structural layer 13, so that the first through hole 02 communicates with the first air guide hole 04, the second air guide hole 07, and the third air guide hole 10 to form a channel, and the first through hole 02 communicates with the annular groove 13a; the lower fixing layer 01c, the first structural layer 03, the second structural layer 06, the third structural layer 09, and the fourth structural layer 13 are all annular structures, and are all set to match the thickness of the base 14 wall.

[0094] In addition, a first metal pad 16 and a second metal pad 17 are provided on the lower fixing layer 01c. The first metal pad 16 is used to guide the electrical properties of the sensing film 11 to the surface layer; the second metal pad 17 is used to guide the electrical properties of the fixed electrode plate 01a to the surface layer; the first metal pad 16 and the second metal pad 17 are both located at the corners of the lower fixing layer 01c.

[0095] Example 6 differs from Example 5 in that: (Refer to...) Figure 11 The lower surface of the base 14 near the fixed electrode plate 01a is provided with several square first through holes 02. The first through holes 02 are evenly spaced along the outer edge of the base 14 and are arranged in a straight line along the thickness direction of the base 14. The inner wall of the channel of the first through hole 02 is provided with a second through hole 08 that communicates with the second cavity 18. The end of the first through hole 02 is provided with a liquid collection trough, which is connected in the base 14 to form an annular groove 13a. The annular groove 13a has an O-shaped cross-section and a depth of 5μm. m; In addition, a first through hole 02 is also provided on the side wall of the base 14. The first through hole 02 is arranged horizontally and communicates with the first through hole 02 arranged vertically. The first through hole 02 arranged horizontally and the second through hole 08 are offset in the vertical direction, and the second through hole 08 is located above the horizontal through hole 02b. By setting the horizontal through hole 02b and the vertical through hole 02a, the airflow is further dispersed, the airflow velocity in a single first through hole 02 is further reduced, and the liquid is reduced from entering the channel with the airflow.

[0096] Preferably, a transverse through-hole 02b is disposed on the first structural layer 03 and perpendicular to the longitudinal through-hole 02a, and the transverse through-hole 02b is distributed along the periphery of the first structural layer 03; the first structural layer 03 is a transitional structural layer with a thickness of 0.6μm, a second structural layer 06 is disposed above the first structural layer 03, and an upper fixing layer 01b is disposed below the first structural layer 03, the upper fixing layer 01b having a thickness of 0.4μm and the lower fixing layer 01c having a thickness of 0.8μm; the second structural layer 06 has a thickness of 1.4μm and is made of Si material, and a second vent 07 communicating with the longitudinal through-hole 02a is provided on the second structural layer 06, and a second through-hole 08 is provided on the inner wall of the second vent 07; the third structural layer 09 has a thickness of 0.4μm, and the fourth structural layer 13 has a thickness of 9μm.

[0097] Three conductive pads for bonding wires are provided in the lower fixed layer 01c, including a first metal pad 16 and two second metal pads 17. The two second metal pads 17 are symmetrically arranged on opposite corners of the lower fixed layer 01c, and the first metal pad 16 is arranged on any one of the other two corners of the lower fixed layer 01c. The two second metal pads 17 are electrically connected to the fixed electrode plate 01a, and the first metal pad 16 is electrically connected to the sensing film 11.

[0098] This invention provides a first through hole 02 on the periphery of the orthogonal projection of the first cavity 15 onto the fixed electrode 01a, avoiding direct opening of the fixed electrode 01a at this location. This prevents liquid from directly entering the second cavity 18 through the hole and affecting the normal operation between the fixed electrode 01a and the sensing membrane 11. In addition, a first through hole 02 communicating with the second cavity 18 is provided on the periphery, and an annular liquid collection trough is provided at the end of the first through hole 02. The interior of the liquid collection trough is connected to form an annular groove 13a, which buffers and collects the fine liquid entering from the first through hole 02 within the annular groove 13a, preventing it from entering the second cavity 18. Furthermore, the first through hole 02 is provided in several quantities to disperse the airflow entering the first through hole 02, reducing the airflow velocity within a single hole, thereby improving liquid deposition. A vent 12 is located at the center of the sensing membrane 11. This vent design ensures that the product maintains pressure balance on both sides of the sensing membrane 11 even in high-temperature environments, extending its service life and preventing vibration caused by slight airflow. Furthermore, it prevents the sensing membrane 11 from becoming deformed due to heat in a sealed environment and being unable to return to its original state. The vent 12 is connected to the second cavity 18 and the first through hole 02, ensuring pressure balance between the second cavity 18 and the outside environment, preventing damage to the sensing membrane 11 when pressure increases in the second cavity 18 or the first cavity 15. An insulating protrusion structure 05 is provided on the upper surface of the fixed electrode plate 01a to prevent the sensing membrane 11 or the fixed electrode plate 01a from being affected by external air pressure, which could cause the fixed electrode plate 01a to become too close to or adhere to the sensing membrane 11, leading to conductivity and membrane failure.

[0099] By providing reinforcing layers on the upper and lower parts of the fixed electrode plate 01a, including a lower fixing layer 01c and an upper fixing layer 01b, the pressure-bearing capacity of the fixed electrode plate 01a is improved from different directions. Simultaneously, the lower fixing layer 01c prevents mechanical damage to the fixed electrode plate 01a from the suction nozzle shroud, thus extending the service life of the fixed electrode plate 01a. By providing an arc-shaped R-angle 09a at the connection between the second through hole 08 and the channel, liquid is deposited, reducing the airflow pressure within the channel and preventing liquid from entering the second cavity 18 through the second through hole 08, while also reducing liquid accumulation at the second through hole 08.

[0100] The working principle of this application is as follows: airflow change → capacitance change → ASIC processing → electrical signal output; when the sensor senses the airflow change, the airflow change causes the distance between the upper fixed plate 01a and the sensing film 11 to change, thereby changing the capacitance value between the fixed plate 01a and the sensing film 11 through the position change of the sensing film 11. Then, this capacitance change signal is transmitted to the ASIC chip for processing. After processing, the ASIC converts this capacitance change into an electrical signal that can be recognized by other chips, ultimately realizing the electronic cigarette application function.

[0101] Centered on the central axis of the base 14, a circular matrix of hundreds of holes is arranged on the wall of the base 14 at a distance of 350 μm from the center, i.e., along the thickness direction of the base layer, the first structural layer 03, the second structural layer 06, and the third structural layer 09. Each hole forms a first through hole 02 in a three-way microchannel structure, and a liquid collection trough is provided at the end of the first through hole 02. The liquid collection trough forms a connected annular groove 13a in the fourth structural layer 13. A second through hole 08 communicating with the second cavity 18 is provided in the channel. When the sensing membrane 11 senses the airflow pressure, the sensing membrane 11 deforms with the airflow direction. With this structure, even if there is a slight liquid, it will fall into the liquid collection trough, avoiding the sensing membrane 11 being directly exposed above or below the airflow sensing, and protecting the sensing membrane 11 from the influence of the external environment and causing failure.

[0102] In existing technologies, to reduce defects, high-cost AOI equipment is used for surface shape recognition during the manufacturing process, resulting in extremely high costs. Additionally, an oil-resistant mesh is attached to the sensor surface, further increasing costs. However, this still cannot completely prevent liquid from entering between the sensing membrane 11 and the fixed electrode plate 01a. By optimizing this design, the MEMS sensor of this invention is less susceptible to environmental damage during back-end packaging, SMT mounting, and use. It can adapt to the connection requirements of external circuits and devices in different application scenarios, achieving universal adaptability of the MEMS structure to various application scenarios in packaging applications. This invention eliminates the need for redesigning the structure and adjusting the packaging process for different application scenarios, reducing R&D costs and time, and facilitating the large-scale promotion and application of MEMS devices.

[0103] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. In the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A barometric pressure MEMS sensor, comprising a base, a sensing diaphragm, and a fixed electrode plate, wherein the base and a first cavity penetrating the thickness of the base; characterized in that: A sensing film and a fixed electrode plate are stacked on one side of the base. The fixed electrode plate is located below the sensing film and is spaced apart to form a second cavity. The base has several first through holes on the side near the fixed electrode plate. The inner wall of the first through holes has a second through hole that communicates with the second cavity. The end of the first through hole has a liquid collection trough. The liquid collection trough is connected in the base to form an annular groove. The first structural layer is a transitional structural layer with a thickness of 0.2μm-1μm, which connects the upper second structural layer and the lower fixed electrode plate. The second structural layer has a thickness of 1μm-1.5μm, and a second through-hole is provided on the second structural layer; The third structural layer, located below the sensing film, is a buffer physical layer to prevent external interference to the sensing film; it has an arc-shaped R-angle near the first through-hole, and the third structural layer is located above the second structural layer; The fourth structural layer is located above the third structural layer. The inner side of the fourth structural layer is provided with a mounting platform for setting the sensing film, so that there is a certain distance between the sensing film and the base. An annular groove is provided in the fourth structural layer. The first through hole passes through the lower fixing layer, the fixing plate, the upper fixing layer, the first structural layer, the second structural layer and the third structural layer in sequence, and communicates with the annular groove in the fourth structural layer.

2. The pressure MEMS sensor according to claim 1, characterized in that: The first cavity is designed without holes at the orthographic projection of the fixed electrode plate.

3. The pressure MEMS sensor according to claim 1, characterized in that: The cross-section of the annular groove is one of O-shape, D-shape, cone shape or trapezoid.

4. The pressure MEMS sensor according to claim 1, characterized in that: An arc-shaped radius (R-angle) is provided at the connection between the first through hole and the second through hole.

5. The pressure MEMS sensor according to claim 1, characterized in that: The fixed electrode plate has a raised structure on the side near the sensing membrane; the sensing membrane has a vent hole.

6. The pressure MEMS sensor according to claim 1, characterized in that: The first through hole is a circular hole or a square hole, and the channel of the first through hole is one of arc shape, straight shape or right angle shape.

7. The pressure MEMS sensor according to claim 6, characterized in that: The first through hole is set on the lower end face of the base and is evenly spaced along the outer edge of the base.

8. The pressure MEMS sensor according to claim 6, characterized in that: The first through hole is located on the lower side and is offset from the second through hole.

9. The pressure MEMS sensor according to claim 1, characterized in that: Reinforcing layers are provided on both sides of the fixed electrode plate.

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