Novel air pressure MEMS sensor

Abstract

The invention belongs to the technical field of semiconductors, and particularly relates to a novel air pressure MEMS sensor which comprises a base and a first cavity penetrating through the thickness of the base. A sensing film and fixed polar plates are stacked on one side of the base, and the fixed polar plates are located below the sensing film and arranged at intervals to form a second cavity; a plurality of first through holes are formed in the side, close to the fixed polar plate, of the base, second through holes communicated with the second cavity are formed in the inner walls of the first through holes, and liquid collection sinking grooves are formed in the tail ends of the first through holes and are communicated in the base to form an annular groove; according to the scheme, the first through hole is formed in the periphery of the orthographic projection of the first cavity on the fixed polar plate, so that direct trepanning on the fixed polar plate is avoided, and liquid is prevented from directly entering the second cavity from the hole to affect normal work between the fixed polar plate and the sensing film; and the tail end of the first through hole is arranged in the base and is communicated with the base to form an annular groove, so that small liquid entering from the first through hole is buffered and collected in the annular groove, and is prevented from entering the second cavity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a new type of air pressure MEMS sensor. BACKGROUND

[0002] The existing MEMS chip is directly from the acoustic industry, and the sensor is used in electronic cigarettes and acoustic applications. Because the principles are different, different requirements are placed on the structure. At present, this method has certain disadvantages. The principle of the MEMS airflow sensor is to convert the distance change between the upper fixed plate and the lower sensing membrane into airflow pressure output, that is, to change the capacitance value through the position change of the sensing membrane, and finally to realize the detection of airflow pressure.

[0003] In the manufacturing process of the existing electronic cigarette MEMS sensor, because of the central air conditioner in the workshop and the compressed gas of the packaging equipment, it is inevitable that a small amount of oily liquid with emulsification will be produced. A certain proportion of emulsified liquid will pollute the sensing membrane. After this phenomenon occurs, more seriously, some product automatic test equipment cannot test and intercept, and when used in terminal customers, it will appear self-starting or phase continuous output, etc. fatal defect; It is specifically shown in the following aspects: 1. Easy to be damaged during packaging: the MEMS bare chip is easily affected by external environmental liquids (oil, water vapor, etc.) during packaging, which can cause the production process liquid (such as oil inside the compressed gas of the packaging equipment, and water vapor with compressed emulsion from the central air conditioner in the workshop) to penetrate through the hole on the top of the fixed plate, causing the fixed plate and the sensing membrane to stick together, resulting in functional failure; 2. Risk in post-processing: the application of MEMS technology in electronic cigarettes involves complex circuit design and micro electronic components. Due to the small size of MEMS devices, the internal circuit layout is relatively dense. If the process control is not proper during production, the MEMS package can be easily affected by external environment (liquid, rosin, tin beads, etc.) during post-processing. The fine liquid, rosin, tin beads, etc. produced during post-processing can easily penetrate through the mesh hole on the fixed plate of the MEMS chip and stick to the lower sensing membrane, resulting in functional failure. Not only will it damage the electronic cigarette equipment, but in severe cases it may also cause battery overheating, burning and even explosion, etc. safety accidents, which poses a threat to the personal safety of the user.

[0004] 3. As shown in the accompanying Figure 9 The existing MEMS product fixed plate has many air holes, and is directly above the sensing membrane, which is easily affected by the external environment and can easily cause functional failure. The thickness of the fixed plate is about 1-2um, and when the air pressure is greater than 90KPa, the sensing membrane can be easily damaged. The sensing membrane can appear slight jitter under slight airflow pressure, which can mislead the airflow signal transmission to the ASIC in application.

[0005] Therefore, it is a technical problem that needs to be solved urgently at present. SUMMARY

[0006] The application provides a novel air pressure MEMS sensor, which solves the problem that in the prior art, liquid enters from the fixed electrode plate air hole, which affects the normal work of the electrode plate and the sensing film, and the sensing film is easily damaged when the air pressure is greater than 90KPa, and the sensing film is slightly shaken by slight air flow pressure, which causes miscommunication signals.

[0007] The application provides the following technical scheme: a novel air pressure MEMS sensor, comprising a base, a sensing film and a fixed electrode plate, wherein the base is provided with a first cavity penetrating through the thickness of the base; the sensing film and the fixed electrode plate are arranged in layers on one side of the base, and the fixed electrode plate is arranged below the sensing film and is spaced apart, so that a second cavity is formed between the fixed electrode plate and the sensing film; the side of the base close to the fixed electrode plate is provided with a plurality of first through holes, the inner wall of the first through hole is provided with a second through hole in communication with the second cavity, and the end of the first through hole is provided with a liquid collecting groove, and the liquid collecting grooves are connected into an annular groove in the base.

[0008] Preferably, the first cavity is provided with no hole at the orthographic projection of the fixed electrode plate, the first through hole is arranged on the wall of the base, so as to avoid damaging the structure corresponding to the fixed electrode plate and the first cavity, the place is provided with no hole in the fixed electrode plate, and the arrangement can directly prevent liquid from entering the second cavity; the plurality of first through holes are arranged at equal intervals along the wall of the base, the channel of the first through hole is provided with the second through hole in communication with the second cavity, and the annular groove is arranged at the end of the channel, first, the air inlet is dispersed through the plurality of first through holes, the flow rate of the air flow in the first through hole is reduced after dispersion, a first filtration is formed, and the annular groove is arranged at the end, the liquid entering the liquid collecting groove from the channel along the air flow reduces the pressure, and then the liquid is deposited in the liquid collecting groove, so as to avoid the liquid entering the second cavity from the second through hole to form a second filtration; the multi-channel filtration mode ensures that the environment in the second cavity is not affected by small liquid.

[0009] Further, the cross section of the annular groove is one of O-shaped, D-shaped, conical or trapezoidal.

[0010] Further, the connection between the first through hole and the second through hole is provided with an arc-shaped R angle. The arc-shaped R angle plays a role in reducing the pressure, so that the liquid is deposited in the annular groove, and the liquid entering the second through hole is reduced.

[0011] Further, the side of the fixed electrode plate close to the sensing film is provided with a protruding structure, the height of the protruding structure is 0.3-0.7 microns, and the diameter is 0.1-1 micron; the protruding structure is made of smooth-surfaced insulating material.

[0012] Preferably, the height of the protruding structure is 0.4-0.6 μm, and the diameter is 0.2-0.8 μm; the protruding structure is distributed on the upper surface of the fixed electrode plate at a certain interval, the interval is a fixed distance or is freely set according to the model, and the protruding structure has the characteristics of smooth surface and insulating material, and is made of Si, and is used as a contact by virtue of good insulation and smoothness, so as to prevent the electroplated conductive thin layer on the fixed electrode plate from adhering to the sensing film.

[0013] More preferably, the height of the protruding structure is 0.5 μm, and the diameter is 0.6 μm.

[0014] Further, the sensing film is provided with an air vent hole with a diameter of 1-6 μm.

[0015] Preferably, the diameter of the air vent hole is 2-5 μm, and the air vent hole is arranged at the center of the sensing film; the air vent hole is designed to balance the air pressure on both sides of the sensing film in a high-temperature environment, prolong the service life of the sensing film, and avoid the product from shaking under the action of slight air flow; and the air vent hole prevents the sensing film from being unable to restore the original state after thermal expansion deformation in a sealed environment.

[0016] More preferably, the diameter of the air vent hole is 3 μm or 4 μm.

[0017] Further, the first through hole is a circular hole or a square hole, and the channel of the first through hole is in an arc shape, a straight line shape, or a right angle shape.

[0018] Further, the first through hole opening is arranged on the lower end surface of the base and is arranged at equal intervals along the outer edge of the base.

[0019] Further, the first through hole opening is arranged on the side surface of the lower end of the base and is arranged in a staggered manner with the second through hole.

[0020] Further, the fixed electrode plate is provided with a reinforcing layer on both sides, the reinforcing layer away from the sensing film is arranged outwardly, and this layer is a lower reinforcing layer; the reinforcing layer close to the sensing film is an insulating layer, and this layer is an upper reinforcing layer.

[0021] Preferably, the upper reinforcing layer is used to reinforce the upper surface of the fixed electrode plate, that is, vertical reinforcement, and the lower reinforcing layer is used to reinforce the lower edge of the fixed electrode plate, that is, horizontal reinforcement; the thickness of the upper reinforcing layer is 0.1-1 μm; the two reinforcing layers and the fixed electrode plate cooperatively enhance the mechanical properties between the fixed electrode plate 01a and the base 14 from different levels, so as to ensure that the sensor can still maintain structural stability and resist external physical impact under complex working conditions.

[0022] More preferably, the thickness of the upper reinforcing layer is 0.2 μm, 0.4 μm, 0.5 μm, 0.6 μm, or 0.8 μm; the upper reinforcing layer is an insulating layer, which prevents current leakage and ensures safety.

[0023] The lower fixed layer is arranged protruding downward to avoid the risk of the fixing plate caused by the hood of the suction nozzle for picking up the chip; the protruding arrangement makes the fixing plate and the outer surface of the lower fixed layer form a certain distance, thereby reducing the significant damage to the fixing plate caused by the hood on the surface of the suction nozzle in the subsequent production process, and avoiding surface defects such as mechanical scratches and micro-cracks on the surface of the fixing plate; The thickness of the lower fixed layer is 0.2-2 μm, which is made of silicon oxide (SiO2), silicon nitride (Si3N4) or other polymer materials, and has the performance of preventing electric conduction and resisting electric interference. The surface of the lower fixed layer is provided with a coating for the purpose of isolating the electric performance and resisting interference. Preferably, the thickness of the lower fixed layer is 0.4 μm, 0.5 μm, 0.8 μm, 1.0 μm, 1.2 μm, 1.5 μm or 1.8 μm.

[0024] Further, the base layer comprises: The first structure layer is a transition structure layer, and the thickness is 0.2-1 μm, which connects the second structure layer above and the fixing plate below; The second structure layer has a thickness of 1-1.5 μm, and the second through hole is arranged on the layer; The third structure layer is a buffer physical layer below the sensing film to avoid external interference to the sensing film; an arc R corner is arranged near the first through hole, and the third structure layer is below the second structure layer; The fourth structure layer is above the third structure layer, and the inner side of the fourth structure layer is provided with a mounting table for arranging the sensing film, so that there is a certain distance between the sensing film and the base, and the fourth structure layer is provided with an annular groove.

[0025] Preferably, the first structure layer is a transition structure layer, and the thickness is 0.3-0.8 μm, which is arranged between the second structure layer above and the upper fixed layer below; the lateral area ratio of the first structure layer is about 20%, which is made of Si material and has good flexibility and excellent mechanical properties. As a transition structure, it ensures smooth transition and good combination between different layers, and reduces stress concentration; the first structure layer further comprises a support part connected with the first structure layer for filling or supporting, which plays a role of buffering and shock absorption; the first gas guide hole connected with the first through hole is arranged on the first structure layer.

[0026] The second structure layer has a thickness of 1.1-1.4 microns, and plays a protective and fixing role for the internal structure; the transverse area ratio of the second structure layer is less than 20%, the second structure layer is made of Si material, has high mechanical strength and good protective performance, the second structure layer is provided with a second gas guide hole communicated with the first through hole, and a second through hole is arranged on the inner wall of the second gas guide hole; the second structure layer plays a protective and fixing role for the internal structure, and the channel, the second through hole and the inner wall of the second structure layer are smooth surfaces.

[0027] The third structure layer is a buffer physical layer and is located below the sensing film, avoids external interference to the sensing film, and plays a fixing role for the sensing film; an arc R angle is arranged near the first through hole; the third structure layer is also provided with a third gas guide hole communicated with the first through hole, the third gas guide hole is provided with an arc R angle near the inlet side of the second through hole, the third gas guide hole is at a right angle with the second through hole; so as to ensure that the liquid outside cannot enter the second cavity through the second through hole.

[0028] The fourth structure layer has a thickness of 5-10 microns, and an installation table is arranged on the inner side of the fourth structure layer; the installation table is used for arranging the sensing film, and a certain distance is kept between the sensing film and the base, so as to play an anti-interference role; the sensing film is arranged on the installation table and is in the same plane as the lower surface of the fourth structure layer; a ring-shaped groove communicated with the channel and the first through hole is arranged on the fourth structure layer, and the cross section of the liquid collecting groove is in the shape of O or D. Preferably, the thickness of the fourth structure layer is 6 microns, 7 microns, 8 microns or 9 microns; the depth of the ring-shaped groove is not more than 5 microns.

[0029] In the embodiment, the first cavity is arranged to raise the height of the entire sensor, increase the space for the sensing film to sense the air flow, and avoid excessive air pressure in the space from causing the sensing film to fail to quickly return to the original position.

[0030] In addition, the base is also provided with a first metal pad and a second metal pad; the first metal pad is used for guiding the electrical performance of the sensing film to the surface layer; the second metal pad is used for guiding the electrical performance of the fixed electrode plate to the surface layer; and the first metal pad and the second metal pad are arranged on the corners of the base.

[0031] It should be noted that the liquid in the application is the liquid in the production process, such as the oil in the compressed gas inside the packaging equipment, the compressed emulsified water vapor in the central air conditioner of the workshop, the fine liquid produced in the back-end processing of the product, rosin, tin beads, etc., and the fine liquid drops produced in different use scenarios after the assembled product leaks oil, which affect the packaging or normal work of the fixed electrode plate and the sensing film.

[0032] It should be understood that the above general description and the following detailed description are only exemplary and cannot limit the application.

[0033] The present application has the following advantages: 1. The first through hole is arranged on the periphery of the first cavity in the fixed plate, avoiding direct hole opening on the fixed plate, thereby preventing impurities such as liquid from directly entering the second cavity from the hole to affect the normal operation between the fixed plate and the sensing film; the no-hole design of the fixed plate optimizes the directly facing area tolerance caused by the hole opening, so that the fixed plate is closer to the "uniform conductive plane", the directly facing area is accurate, and the medium environment is stable; the no-hole fixed plate reduces the leakage and avoids the capacitance fluctuation, directly ensuring that the charge of the Backplate voltage is evenly distributed in the stable voltage division; in addition, the first through hole is arranged in communication with the second cavity, and an annular liquid collecting groove is arranged at the end of the first through hole, the inside of the liquid collecting groove is communicated to form an annular groove, so that the small liquid entering from the first through hole is buffered and collected in the annular groove, preventing it from entering the second cavity; the first through hole is arranged in a plurality of numbers, which can disperse the air flow entering the first through hole, reduce the flow rate of the airflow in a single hole, and facilitate the deposition of liquid.

[0034] 2. The air vent is arranged at the center of the sensing film, and the air vent is designed to enable the product to maintain the balance of the air pressure on both sides of the sensing film in a high-temperature environment, thereby prolonging the service life of the sensing film, and avoiding the product from shaking under the action of a slight air flow; in addition, the sensing film cannot recover to the original state after thermal expansion deformation in a sealed environment. The air vent is arranged in communication between the second cavity and the first through hole, which can ensure the air pressure balance between the second cavity and the outside, and avoid damaging the sensing film when the pressure of the second cavity or the first cavity increases.

[0035] 3. The insulating protruding structure is arranged on the upper surface of the fixed plate, avoiding the influence of the sensing film or the fixed plate on the external air pressure, so that the fixed plate and the sensing film are close to or bonded together for conduction, causing the failure of the sensing film.

[0036] 4. The reinforcing layer is arranged on the upper and lower layers of the fixed plate, thereby improving the pressure bearing capacity of the fixed plate from different directions, and the lower reinforcing layer can avoid mechanical damage of the fixed plate by the mouthpiece, thereby improving the service life of the fixed plate.

[0037] 5. The arc-shaped R angle is arranged at the connection between the second through hole and the channel, which plays a role in depositing liquid, reduces the airflow pressure in the channel at this position, thereby avoiding the liquid from entering the second cavity from the second through hole, and reducing the liquid accumulation at the second through hole.

[0038] 6. The present application is not limited to the application in the field of electronic cigarette sensors, but can also be applied to the special structure packaging of MEMS chips and airflow pressure detection devices. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1A cross-sectional view of a new air pressure MEMS sensor according to an embodiment of the present application; Figure 2 A cross-sectional view of a new air pressure MEMS sensor according to an embodiment of the present application; Figure 1 A structural diagram of a substrate in Figure 3 A second via hole distribution diagram of a new air pressure MEMS sensor according to an embodiment of the present application; Figure 4 A first annular groove arrangement diagram of a new air pressure MEMS sensor according to an embodiment of the present application; Figure 5 An arc-shaped R-angle amplification diagram of a new air pressure MEMS sensor according to an embodiment of the present application; Figure 6 A first structural layer top view of a new air pressure MEMS sensor according to an embodiment of the present application; Figure 7 A top view of a new air pressure MEMS sensor according to an embodiment of the present application; Figure 8 A cross-sectional view of a new air pressure MEMS sensor according to an embodiment of the present application; Figure 9 A cross-sectional view of a prior art structure; Figure 10 A first structural cross-sectional view of a new air pressure MEMS sensor according to an embodiment of the present application; Figure 11 A second structural cross-sectional view of a new air pressure MEMS sensor according to an embodiment of the present application; Figure 12 A second annular groove arrangement diagram of a new air pressure MEMS sensor according to an embodiment of the present application; Figure 13 A third annular groove arrangement diagram of a new air pressure MEMS sensor according to an embodiment of the present application; 01, base layer; 01a, fixed electrode plate; 01b, upper fixed layer; 01c, lower fixed layer; 02, first via hole; 02a, longitudinal via hole; 02b, transverse via hole; 03, first structural layer; 03a, support portion; 04, first gas guide hole; 05, protruding structure; 06, second structural layer; 07, second gas guide hole; 08, second via hole; 09, third structural layer; 09a, arc-shaped R-angle; 10, third gas guide hole; 11, sensing membrane; 12, air 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 DESCRIPTION

[0040] Embodiments of the present application will be described below with reference to the accompanying drawings.

[0041] Embodiment one, refer to Figures 1-8 A new type of air pressure MEMS sensor, including base 14, sensing film 11 and fixed plate 01a, the thickness of base 14 is 200-400 μm, the thickness of base 14 in this embodiment is 400 μm, base 14 and the first cavity 15 through the thickness of base 14;Base 14 is provided with sensing film 11 and conductive fixed plate 01a on one side, the thickness of sensing film 11 is 0.5 μm, fixed plate 01a is located below sensing film 11 and is spaced apart, so that the second cavity 18 is formed between fixed plate 01a and sensing film 11;Base 14 is provided with a plurality of first through holes 02 on the side close to fixed plate 01a, first through hole 02 is provided on the lower end surface of base 14, the inner wall of first through hole 02 is provided with second through hole 08 communicated with second cavity 18, the end of first through hole 02 is provided with liquid collecting groove, the liquid collecting groove is communicated into annular groove 13a in base 14, the depth of annular groove 13a is 4 μm.

[0042] Preferably, the thickness of fixed plate 01a is 4 μm, the orthographic projection of first cavity 15 on fixed plate 01a is provided with no hole, the first through hole 02 is provided on the wall of base 14, so as to avoid damaging the structure corresponding to fixed plate 01a and first cavity 15, that is, the place corresponding to fixed plate 01a and first cavity 15 of fixed plate 01a is provided with no hole, which can directly prevent liquid from entering into second cavity 18;A plurality of first through holes 02 are provided on the wall of base 14 at equal intervals, the channel of first through hole 02 is longitudinally arranged along the thickness direction of base 14, the channel is provided with second through hole 08 communicated with second cavity 18, and annular groove 13a is arranged at the end of the channel, first, the gas inlet is dispersed through a plurality of first through holes 02, the flow rate of gas flow in a single first through hole 02 is reduced after dispersion, and the first filtering is formed;At the same time, the annular groove 13a is arranged at the end of the channel, the liquid entering into annular groove 13a from the channel along with the gas flow will reduce the pressure, and then the liquid will be deposited in the liquid collecting groove, so as to avoid the liquid entering into second cavity 18 from second through hole 08 to form the second layer of filtering;The multi-channel filtering mode is adopted, so as to ensure that the environment in second cavity 18 is not affected by small liquid.

[0043] In the embodiment, the cross section of annular groove 13a is O-shaped, which plays a role in reducing pressure and collecting liquid for the gas flow entering into annular groove 13a from first through hole 02, and reduces the liquid entering into second cavity 18 from second through hole 08;The connection between first through hole 02 and second through hole 08 is provided with arc R angle 09a, which plays a role in reducing pressure, promotes the deposition of liquid in annular groove 13a, avoids the aggregation of liquid at second through hole 08, and further reduces the liquid entering into second through hole 08.

[0044] In the embodiment, the fixed electrode plate 01a is provided with a protruding structure 05 near one side of the sensing film 11, the height of the protruding structure 05 is 0.5 μm, and the diameter is 0.6 μm; the protruding structure 05 is made of smooth-surfaced insulating material. The sensing film 11 is provided with a gas vent 12 with a diameter of 3 μm.

[0045] 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 performance of the sensing film 11 to the surface layer; the second metal pad 17 is used to guide the electrical performance of the fixed electrode plate 01a to the surface layer; the first metal pad 16 and the second metal pad 17 are both arranged on the corners of the base 14.

[0046] In the second embodiment, the difference between the second embodiment and the first embodiment is that the thickness of the base 14 is 220 μm, the thickness of the sensing film 11 is 0.2 μm, the first through hole 02 is arranged obliquely along the thickness direction of the base 14, so that the first through hole 02 forms a certain oblique angle with the annular groove 13a, and the gas flow rotates in the annular groove 13a, so that the liquid entering the annular groove 13a from the first through hole 02 is quickly deposited in the annular groove 13a under the action of centrifugal force, reducing the risk of liquid entering the second through hole 08; as shown in the figure, the cross section of the annular groove 13a is D-shaped, and the depth of the annular groove 13a is 2 μm. Figure 13

[0047] The inner wall of the channel is provided with an arc R angle 09a connected with the second through hole 08, the arc R angle 09a is arranged near one side of the annular groove 13a, the arc R angle 09a plays a role in reducing pressure, promoting the deposition of liquid in the annular groove 13a, and further reducing the liquid entering the second through hole 08.

[0048] In the embodiment, the thickness of the fixed electrode plate 01a is 5 μm, the fixed electrode plate 01a is provided with a protruding structure 05 near one side of the sensing film 11, the height of the protruding structure 05 is 0.4 μm, the diameter is 0.2 μm, and the protruding structure 05 is a hemispherical structure; the protruding structure 05 is made of smooth-surfaced insulating material, and the protruding structure 05 is arranged in a matrix on the fixed electrode plate 01a; the sensing film 11 is provided with a gas vent 12 with a diameter of 2 μm, and the gas vent 12 is arranged at the center of the sensing film 11; the arrangement of the gas vent 12 enables the product to balance the air pressure on both sides of the sensing film 11 in a high-temperature environment, prolongs the service life of the sensing film 11, and avoids the phenomenon of shaking of the product under the action of slight air flow; prevents the sensing film 11 from being unable to restore the original state after thermal expansion deformation in a sealed environment.

[0049] ​In the third embodiment, the first through hole 02 is longitudinally arranged 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 linear. The end of the first through hole 02 is in communication with the annular groove 13a, and the cross section of the annular groove 13a is tapered. The structure facilitates the deposition of liquid in the airflow by the annular groove 13a.

[0050] In the embodiment, the thickness of the fixed electrode plate 01a is 6 μm, the side of the fixed electrode plate 01a close to the sensing film 11 is provided with a protruding structure 05, the height of the protruding structure 05 is 0.6 μm, the diameter of the protruding structure 05 is 0.8 μm, the protruding structure 05 is a cylindrical structure, the protruding structure 05 is made of an insulating material with smooth surface, and the protruding structure 05 is randomly distributed on the fixed electrode plate 01a in the form of scattered points. The protruding structure 05 serves as a contact point by virtue of good insulation and smoothness, and is used to prevent the electroplated conductive thin layer on the fixed electrode plate 01a from adhering to the sensing film 11.

[0051] The sensing film 11 is provided with a gas escape hole 12 with a diameter of 5 μm. The gas escape hole 12 is arranged on one side of the central axis of the sensing film 11, so as to ensure the sensitivity of the sensing film 11 to air pressure and prevent the sensing film 11 from being unable to restore the original state after thermal expansion and deformation in a sealed environment.

[0052] In the embodiment, the upper and lower layers of the fixed electrode plate 01a are provided with reinforcing layers, the reinforcing layers include a lower fixed layer 01c and an upper fixed layer 01b, the lower fixed layer 01c is outwardly protruding, and the upper fixed layer 01b is an insulating layer and is arranged close to the sensing film 11. Preferably, the upper fixed layer 01b is used to reinforce the upper surface of the fixed electrode plate 01a, i.e. vertical reinforcement, and the lower fixed layer 01c is used to reinforce the lower edge of the fixed electrode plate 01a, i.e. horizontal reinforcement. The thickness of the upper fixed layer 01b is 0.3 μm. The two fixed layers and the fixed electrode plate 01a cooperatively enhance the mechanical properties between the fixed electrode plate 01a and the base 14 from different layers, so as to ensure that the sensor can still maintain structural stability and resist external physical impact under complex working conditions.

[0053] More preferably, the upper fixed layer 01b is an insulating layer, which prevents current leakage and ensures safety.

[0054] The lower fixed layer 01c is arranged protruding downward to avoid the risk of the fixed electrode plate 01a caused by the hood of the suction nozzle when the suction nozzle picks up the chip. After the protruding arrangement, the fixed electrode plate 01a and the outer surface of the lower fixed layer 01c form a certain distance, thereby reducing the significant damage of the fixed electrode plate 01a caused by the hood on the surface of the suction nozzle in the subsequent production process, avoiding the surface defects such as mechanical scratches and micro-cracks on the surface of the fixed electrode plate 01a. The thickness of the lower fixed layer 01c is 0.5 μm, which is made of silicon oxide (SiO2), silicon nitride (Si3N4) or other polymer materials, and has the performance of preventing electric conduction and resisting electric interference. The surface of the lower fixed layer 01c is provided with a coating layer, which is used for isolating the electric performance and resisting interference.

[0055] In example four, the difference from example three is that: Figure 10 The thickness of the base 14 is 300 μm, the thickness of the sensing film 11 is 0.5 μm, the first through hole 02 is arranged on the side surface of the lower end of the base 14, the channel of the first through hole 02 is in a right angle shape, the end of the first through hole 02 is communicated with the annular groove 13a, the first through hole 02 is arranged in a staggered manner with the second through hole 08, the second through hole 08 is arranged 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 located on the same horizontal straight line; the cross section of the annular groove 13a is arranged in a trapezoidal shape, which facilitates the deposition of liquid in the airflow by the annular groove 13a, and the depth of the annular groove 13a is 3 μm.

[0056] In the embodiment, the upper and lower layers of the fixed electrode plate 01a are provided with reinforcing layers, which include the lower fixed layer 01c and the upper fixed layer 01b. The lower fixed layer 01c is arranged protruding outward, and the upper fixed layer 01b is an insulating layer arranged close to one side of the sensing film 11 to prevent current leakage and ensure safety.

[0057] Preferably, the upper fixed layer 01b is used to reinforce the upper surface of the fixed electrode plate 01a, i.e. vertical reinforcement, and the lower fixed layer 01c is used to reinforce the lower edge of the fixed electrode plate 01a, i.e. horizontal reinforcement. The thickness of the upper fixed layer 01b is 0.4 μm, and the thickness of the lower fixed layer 01c is 1.2 μm. The two fixed layers and the fixed electrode plate 01a cooperate to enhance the mechanical properties between the fixed electrode plate 01a and the base 14 from different levels, to ensure that the sensor can still maintain structural stability under complex working conditions and resist external physical impact.

[0058] The lower fixed layer 01c is arranged protruding downward, which is used to avoid the risk of the fixed plate 01a caused by the suction nozzle when the suction nozzle picks up the chip, and avoid the surface defects such as mechanical scratches and micro-cracks on the surface of the fixed plate 01a. The lower fixed layer 01c is made of silicon oxide (SiO2), silicon nitride (Si3N4) or other polymer materials, which has the performance of preventing electric conduction and anti-electric interference. The surface of the lower fixed layer 01c is provided with a coating for the purpose of isolating the electric performance and anti-interference effect.

[0059] In the embodiment, the base 14 is provided with a plurality of square first through holes 02 on the lower surface of the side close to the fixed plate 01a. The first through holes 02 are arranged at equal intervals along the outer edge of the base 14, and are arranged longitudinally along the thickness direction of the base 14 in a straight line shape. The inner wall of the channel of the first through hole 02 is provided with a second through hole 08 in communication with the second cavity 18. The end of the first through hole 02 is provided with a liquid collecting trough, which is connected in a ring-shaped groove 13a in the base 14, as shown in Figure 12 The cross section of the ring-shaped groove 13a is in the shape of O.

[0060] In the embodiment, the fixed plate 01a is provided with a protruding structure 05 on the side close to the sensing film 11. The protruding structure 05 is arranged at equal intervals in a concentric circle on the fixed plate 01a. The height of the protruding structure 05 is 0.5 μm, and the diameter is 0.5 μm. The protruding structure 05 is made of insulating material with smooth surface, and the material is Si. The protruding structure 05 is used as a contact point by virtue of good insulation and smoothness, which is used to prevent the electroplated conductive thin layer on the fixed plate 01a from adhering to the sensing film 11.

[0061] In the embodiment, the sensing film 11 is provided with a gas vent 12 with a diameter of 4 μm. The gas vent 12 is arranged at the center of the sensing film 11. The gas vent 12 is arranged to balance the air pressure on the upper and lower surfaces of the sensing film 11 in a high temperature environment, thereby prolonging the service life of the sensing film 11, and avoiding the phenomenon of shaking of the product under the action of slight air flow. The sensing film 11 is prevented from being unable to restore to the original state after thermal expansion and deformation in a sealed environment.

[0062] In the embodiment, the upper and lower layers of the fixed plate 01a are provided with a reinforcing layer, which includes a lower fixed layer 01c and an upper fixed layer 01b. The lower fixed layer 01c is arranged protruding outward. The upper fixed layer 01b is an insulating layer and is arranged on the side close to the sensing film 11, which prevents current leakage and ensures safety.

[0063] Preferably, the upper fixed layer 01b is used to reinforce the upper surface of the fixed electrode plate 01a, that is, the vertical direction reinforcement, and the lower fixed layer 01c is used to reinforce the lower edge of the fixed electrode plate 01a, that is, the horizontal direction reinforcement. The thickness of the upper fixed layer 01b is 0.8 μm, and the thickness of the lower fixed layer 01c is 1.8 μm. The two fixed layers cooperate with the fixed electrode plate 01a to enhance the mechanical properties between the fixed electrode plate 01a and the base 14 from different levels, so as to ensure that the sensor can still maintain structural stability and resist external physical impact under complex working conditions.

[0064] More preferably, the lower fixed layer 01c is protruding downward, which is used to avoid the risk of the fixed electrode plate 01a being brought by the suction nozzle when the suction nozzle takes the chip. After the protruding arrangement, the fixed electrode plate 01a and the outer surface of the lower fixed layer 01c form a certain distance, thereby reducing the significant damage of the fixed electrode plate 01a caused by the existence of the suction nozzle surface in the subsequent production process. The surface defects such as mechanical scratches and micro-cracks on the surface of the fixed electrode plate 01a are avoided. The lower fixed layer 01c is made of silicon oxide (SiO2), silicon nitride (Si3N4) or other polymer materials, which has the performance of preventing electric conduction and resisting electric interference. The surface of the lower fixed layer 01c is provided with a coating layer for the purpose of isolating the electric performance and resisting interference.

[0065] In the embodiment, the chip structure further comprises a base layer 01, and the base layer 01 comprises: The first structure layer 03 is a transition structure layer, and the thickness is 0.5 μm. The second structure layer 06 is arranged above the first structure layer 03, and the upper fixed layer 01b is arranged below the first structure layer 03. The lateral area ratio of the first structure layer 03 is 20%, and the first structure layer 03 is made of Si material and has good flexibility and excellent mechanical properties. As a transition structure, the first structure layer 03 ensures smooth transition and good combination between different layers, and reduces stress concentration. The first structure layer 03 further comprises a support part 03a connected with the first structure layer 03, which is used for filling or supporting and plays a role of buffering and shock absorption. The first gas guide hole 04 connected with the first through hole 02 is arranged on the first structure layer 03.

[0066] The second structure layer 06 has a thickness of 1.1 μm and plays a role of protection and fixation for the internal structure. The lateral area ratio of the second structure layer 06 is 19%, and the second structure layer 06 is made of Si material and has high mechanical strength and good protection performance. The second gas guide hole 07 communicating with the first through hole 02 is arranged on the second structure layer 06. The second through hole 08 is arranged on the inner wall of the second gas guide hole 07. The second structure layer 06 is arranged to protect and fix the internal structure. The channel, the second through hole 08 and the inner wall of the second structure layer 06 are smooth surfaces.

[0067] The third structure layer 09 is a buffer physical layer and is located below the sensing film 11, has a thickness of 0.5 μm, avoids external interference to the sensing film 11, and plays a fixing role on the sensing film 11; an arc R angle 09a is arranged near the first through hole 02; the third structure layer 09 is also provided with a third air guide hole 10 which is in communication with the first through hole 02, and the third air guide hole 10 is provided with an arc R angle 09a near the inlet side of the second through hole 08, and the third air guide hole 10 is at a right angle with the second through hole 08; so as to ensure that the liquid outside cannot enter the second cavity 18 through the second through hole 08.

[0068] The fourth structure layer 13 has a thickness of 6 μm, an installation table is arranged on the inner side of the structure layer for arranging the sensing film 11, and a certain distance is kept between the sensing film 11 and the base 14 to play an anti-interference role; the sensing film 11 is arranged on the installation table and is on the same plane as the lower surface of the fourth structure layer 13; an annular groove 13a is arranged on the fourth structure layer 13 and is in communication with the channel and the first through hole 02, and the depth of the annular groove 13a is 2 μm.

[0069] The first cavity 15 is arranged to raise the height of the entire sensor, increase the space for the sensing film 11 to sense the airflow, and avoid that the space is too large in air pressure and the sensing film 11 cannot quickly return to the original position.

[0070] The first through hole 02 is arranged through the lower fixed layer 01c, the fixed electrode plate 01a, the upper fixed layer 01b, the first structure layer 03, the second structure layer 06, and the third structure layer 09 in sequence and is in communication with the annular groove 13a in the fourth structure layer 13, so that the first through hole 02 is in communication with the first air guide hole 04, the second air guide hole 07, and the third air guide hole 10 and forms a channel, and the first through hole 02 is in communication with the annular groove 13a; the lower fixed layer 01c, the first structure layer 03, the second structure layer 06, the third structure layer 09, and the fourth structure layer 13 are all circular ring structures and are matched with the thickness of the wall of the base 14.

[0071] In addition, the first metal pad 16 and the second metal pad 17 are also arranged on the lower fixed layer 01c, the first metal pad 16 is used for guiding the electrical performance of the sensing film 11 to the surface layer, and the second metal pad 17 is used for guiding the electrical performance of the fixed electrode plate 01a to the surface layer; the first metal pad 16 and the second metal pad 17 are both arranged on the corner of the lower fixed layer 01c.

[0072] In the embodiment six, the difference from the embodiment five is that the first through hole 02 is arranged through the lower fixed layer 01c, the fixed electrode plate 01a, the upper fixed layer 01b, the first structure layer 03, the second structure layer 06, and the third structure layer 09 in sequence and is in communication with the annular groove 13a in the fourth structure layer 13. Figure 11The lower surface of the base 14 near the side of the fixed electrode plate 01a is provided with a plurality of square first through holes 02, the first through holes 02 are equidistantly arranged along the outer edge of the base 14, the first through holes 02 are linearly arranged 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 which is in communication with the second cavity 18, the end of the first through hole 02 is provided with a liquid collecting groove, the liquid collecting grooves are connected to form an annular groove 13a in the base 14, the cross section of the annular groove 13a is O-shaped, and the depth of the annular groove 13a is 5μm; in addition, the sidewall of the base 14 is also provided with the first through hole 02, the first through hole 02 is transversely arranged and is in communication with the longitudinally arranged first through hole 02, the transversely arranged first through hole 02 is vertically arranged with the second through hole 08, and the second through hole 08 is located above the transversely arranged first through hole 02, by arranging the transversely arranged first through hole 02 and the longitudinally arranged first through hole 02, the gas flow entering is further dispersed, and the gas flow speed in the single first through hole 02 is further reduced, and the liquid entering the channel with the gas flow is reduced.

[0073] Preferably, the transversely arranged first through hole 02 is arranged on the first structure layer 03 and is vertically arranged with the longitudinally arranged first through hole 02, the transversely arranged first through hole 02 is distributed along the periphery of the first structure layer 03; the first structure layer 03 is a transition structure layer, the thickness is 0.6μm, the second structure layer 06 is arranged above the first structure layer 03, the upper fixed layer 01b is below the first structure layer 03, the thickness of the upper fixed layer 01b is 0.4μm, and the thickness of the lower fixed layer 01c is 0.8μm; the thickness of the second structure layer 06 is 1.4μm, the second structure layer 06 is made of Si material, the second structure layer 06 is provided with the second gas guide hole 07 which is in communication with the longitudinally arranged first through hole 02, the inner wall of the second gas guide hole 07 is provided with the second through hole 08; the thickness of the third structure layer 09 is 0.4μm, and the thickness of the fourth structure layer 13 is 9μm.

[0074] Three wire bonding conductive pads including a first metal pad 16 and two second metal pads 17 are arranged on the lower fixed layer 01c, the two second metal pads 17 are symmetrically arranged on the opposite corners of the lower fixed layer 01c, 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 with the fixed electrode plate 01a, and the first metal pad 16 is electrically connected with the sensing film 11.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] A circular matrix of several hundred holes is arranged on the wall of the base 14 at a distance of 350um from the center position, 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 forming a three-way microchannel structure first through hole 02, and a liquid collecting trough is arranged at the end of the first through hole 02, the liquid collecting trough forming a continuous annular groove 13a in the fourth structural layer 13, and a second through hole 08 is arranged in the channel and communicates with the second cavity 18, when the sensing film 11 senses the airflow pressure, the sensing film 11 deforms along the airflow direction; even if there is a small amount of liquid, it will fall into the liquid collecting trough, avoiding the sensing film 11 being directly exposed above or below the airflow sensing, protecting the sensing film 11 from being damaged by the external environment.

[0079] In order to reduce defects in the prior art, high-priced AOI equipment is used for surface shape recognition in the manufacturing process, the cost is extremely high, and an oil-proof net is attached to the surface of the sensor, increasing the cost, but still cannot completely solve the problem of liquid entering between the sensing film 11 and the fixed electrode plate 01a; after optimizing the design, the MEMS sensor of the present application is not easily damaged by the environment in the process of back-end packaging application and SMT mounting and use, can adapt to the connection requirements of external circuits and devices in different application scenarios, and realizes the general adaptation of the MEMS structure to various application scenarios in packaging application. The present application does not need to redesign the structure and adjust the packaging process for different application scenarios, reduces the research and development cost and time, and is conducive to the large-scale promotion and application of MEMS devices.

[0080] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application; in the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A novel barometric MEMS sensor comprising a base, a sensing membrane and a fixed plate, the base and a first cavity through the thickness of the base; characterized in that: The side of the base is provided with an inductive film and a fixed electrode plate in a stacked manner, the fixed electrode plate is located below the inductive film and is provided in a spaced manner to form a second cavity; the side of the base close to the fixed electrode plate is provided with a plurality of first through holes, 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 groove, and the liquid collecting grooves are connected in a ring groove in the base.

2. The novel baro-MEMS sensor according to claim 1, characterized in that: The first cavity is provided with no hole at the orthographic projection of the fixed electrode plate.

3. The novel baro-MEMS sensor of claim 1, wherein: The cross section of the ring groove is one of O-shaped, D-shaped, conical or trapezoidal.

4. The novel baro-MEMS sensor of claim 1, wherein: The first through hole is provided with an arc R angle at the connection with the second through hole.

5. The novel baro-MEMS sensor according to claim 1, wherein: The side of the fixed electrode plate close to the inductive film is provided with a convex structure; the inductive film is provided with a deflation hole.

6. The novel baro-MEMS sensor of claim 1, wherein: The first through hole is a circular hole or a square hole, and the channel of the first through hole is one of arc-shaped, linear or right-angle shaped.

7. The novel baro-MEMS sensor of claim 6, wherein: The first through hole opening is arranged on the lower end face of the base, and is arranged at equal intervals along the outer edge of the base.

8. The novel baro-MEMS sensor of claim 6, wherein: The first through hole opening is arranged on the lower end side face and is arranged in a staggered manner with the second through hole.

9. The novel baro-MEMS sensor of claim 1, wherein: The two sides of the fixed electrode plate are provided with reinforcing layers.

10. The novel baro-MEMS sensor according to any one of claims 1-9, characterized in that: Further comprising a base layer, the base layer comprises: The first structure layer is a transition structure layer, the thickness is 0.2-1 μm, and the first structure layer is connected to the second structure layer above and the fixed electrode plate below; The second structure layer has a thickness of 1-1.5 μm, and the second structure layer is provided with a second through hole; The third structure layer is a buffer physical layer located below the inductive film, which avoids external interference to the inductive film; the third structure layer is provided with an arc R angle close to the first through hole, and the third structure layer is located below the second structure layer; The fourth structure layer is located above the third structure layer, the inner side of the fourth structure layer is provided with a mounting table for arranging the inductive film, so that there is a certain distance between the inductive film and the base, and the fourth structure layer is provided with a ring groove.

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