MEMS sensor and manufacturing method thereof

Abstract

The invention belongs to the field of MEMS sensors, and discloses an MEMS sensor and a manufacturing method thereof, and the sensor comprises a first supporting seat with a back cavity; the vibrating diaphragm seat ring is embedded in the end side of the first supporting seat, and the middle of the vibrating diaphragm seat ring corresponds to the back cavity; the periphery of the vibrating diaphragm is embedded in the vibrating diaphragm seat ring, and the vibrating diaphragm correspondingly covers the back cavity; the second supporting seat is provided with a cavity and is arranged at one end, provided with the vibrating diaphragm, of the first supporting seat, and the cavity corresponds to the vibrating diaphragm and the back cavity; the back plate is provided with a plurality of sound holes, and the back plate is arranged on one end side, far away from the first supporting seat, of the second supporting seat and covers the cavity; the diaphragm seat ring is made of an elastic material. The vibrating diaphragm is embedded and mounted through the elastic vibrating diaphragm seat ring, so that the vibrating diaphragm has better sensitivity and compliance, and the detection is more sensitive and accurate; an anchoring connection part of the vibrating diaphragm is canceled, so that the problem of stress concentration of the connecting part of the vibrating diaphragm is effectively avoided or reduced, and the damage risk of the vibrating diaphragm is reduced; and meanwhile, the vibrating diaphragm seat ring also has the effects of muting, attenuating vibration, improving resonance and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of MEMS sensors, and particularly relates to a MEMS sensor and a manufacturing method thereof. BACKGROUND

[0002] A MEMS (Micro-Electro-Mechanical-System) sensor is a sensor based on a micro-electro-mechanical system, and has multiple types and can be used to detect physical quantities such as pressure, acceleration, temperature, and sound. Among them, a capacitive MEMS acoustic sensor is a widely used MEMS sensor, and its core structure is a micro-capacitive sensor composed of a diaphragm and a back plate, which is integrated with an ASIC chip (for signal processing) to form a sensor; the principle is that sound pressure causes the diaphragm to shift, changes the capacitance value between the diaphragm and the back plate, and the change in the capacitance value is converted into an electrical signal by the ASIC chip, thereby realizing the detection of sound.

[0003] Among them, the diaphragm is particularly important, and the performance of the diaphragm directly affects the detection result of the sensor. At present, the improvement direction of the diaphragm is mainly to optimize the performance of the diaphragm from the aspects of the structure setting, material selection, and fixing structure of the diaphragm, such as the improvements recorded in patents 202410887978.8 and 201780042283.8.

[0004] However, the diaphragm of the existing MEMS sensor still has a high risk of damage due to stress concentration at the fixed position during use, which affects the detection accuracy and service life of the sensor. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application aims to provide a MEMS sensor and a manufacturing method thereof. The diaphragm of the sensor is embedded and installed by an elastic diaphragm race, so that the diaphragm movement has better sensitivity and compliance, making the detection more sensitive and accurate. By embedded installation, the anchoring connection position of the diaphragm is cancelled, which can effectively avoid or reduce the problem of stress concentration of the diaphragm at the connection position, and reduce the risk of diaphragm damage. At the same time, the setting of the diaphragm race also plays the role of silence, vibration attenuation, and improvement of resonance.

[0006] The technical scheme adopted by the present application is as follows: The MEMS sensor comprises: a first support seat having a back cavity; a diaphragm race embedded on one end side of the first support seat, the middle part of the diaphragm race corresponding to the back cavity; a diaphragm embedded in the diaphragm race, corresponding to cover the back cavity; The second support has a cavity. The second support is disposed on the end of the first support where the diaphragm is located. The cavity corresponds to the diaphragm and the back cavity. A back plate with several sound holes is provided on it. The back plate is located on the side of the second support base away from the first support base and covers the cavity. The diaphragm housing is made of an elastic material.

[0007] In one embodiment of this application, the diaphragm housing includes a lower housing and an upper housing that are adapted to each other; the periphery of the diaphragm is embedded between the lower housing and the upper housing.

[0008] In one embodiment of this application, the lower seat ring is embedded in the seat ring groove of the first support seat, the bottom of the lower seat ring is provided with a first fitting limiting part adapted to the first support seat, and the upper part of the lower seat ring is provided with a second fitting limiting part adapted to the diaphragm; the upper seat ring is covered on the lower seat ring and on the periphery of the diaphragm.

[0009] In one embodiment of this application, the material of the diaphragm seat ring includes one or more of silicone, silicone resin, fluororubber, and styrene-butadiene rubber, and the elastic modulus of the diaphragm seat ring is 0.8~2.5MPa.

[0010] In one embodiment of this application, the diaphragm is provided with a plurality of lugs evenly distributed around its circumference, and there is a smooth transition notch between adjacent lugs; the lower side of the lug is provided with a fitting and mounting part, which is adapted to fit and fit with the second fitting and limiting part; the diaphragm seat completely covers the notch.

[0011] In one embodiment of this application, the second support seat covers the first support seat and the diaphragm seat ring; the cavity of the second support seat has a conical cavity portion, which expands from the end near the back plate to the end near the diaphragm.

[0012] In one embodiment of this application, the diaphragm has an anti-sticking layer on the side facing the back plate.

[0013] The MEMS sensor manufacturing method includes the following steps: S100, forming a first support seat, the first support seat having a seat groove and a back cavity; S200, forming a diaphragm seat ring, the diaphragm seat ring including a lower seat ring and an upper seat ring, the upper part of the lower seat ring being provided with a second fitting and limiting part in the circumferential direction; S300, forming a diaphragm, the diaphragm including a main diaphragm layer and an anti-adhesion layer, the diaphragm having lugs and notches; S400, forming a second support base, the second support base having a cavity; S500, forming a back plate, the back plate having acoustic holes.

[0014] In one embodiment of this application, step S100 specifically includes: S110, a first material layer is provided as a first support base, and the first material layer is etched to form the seat groove; S120, etching the first material layer to form the back cavity; Step S200 specifically includes: S210, a second material layer serving as a lower seat ring is provided in the seat ring groove, and the second material layer is etched to form the second fitting and limiting portion; S220, a third material layer serving as an upper ring is provided on the first support, the lower ring, and the diaphragm, and the periphery of the third material layer is etched to form the outer ring outline of the upper ring; S230, Etching the middle part of the third material layer to form the inner ring outline of the upper seat ring; Step S300 specifically includes: S310, a fourth material layer serving as the main diaphragm layer is provided on the first support and the lower seat ring; S320, a fifth material layer is provided on the fourth material layer as an anti-adhesion layer for the diaphragm; S330, etching the fourth and fifth material layers to form the lugs and notches; Step S400 specifically includes: S410, a sixth material layer is provided as a second support, and the sixth material layer is etched to form a cavity for the second support; Step S500 specifically includes: S510, a seventh material layer serving as a backplate insulation layer is provided on the second support; S520, an eighth material layer is provided on the seventh material layer as a backplate conductive layer; S530, etching the seventh and eighth material layers to form acoustic holes.

[0015] In one embodiment of this application, the method includes the sequentially performed steps S110, S210, S120, S310, S320, S330, S220, S410, S230, S510, S520, and S530.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The MEMS sensor and its manufacturing method of the present invention feature a diaphragm that is fitted and mounted using an elastic diaphragm mount, which improves the sensitivity and compliance of the diaphragm movement, resulting in more sensitive and accurate detection. Furthermore, the fitted mounting eliminates the anchoring connection of the diaphragm, effectively avoiding or reducing stress concentration at the connection points and lowering the risk of diaphragm damage. Simultaneously, the diaphragm mount also serves to reduce noise, attenuate vibrations, and improve resonance. The manufacturing process is simple and the processing cost is low.

[0017] The diaphragm is connected by multiple circumferentially distributed lug structures, with smooth notches between the lugs. This allows the diaphragm to have a better stress distribution mode, avoids or reduces stress concentration during vibration, and further reduces the risk of diaphragm damage.

[0018] An anti-stick layer is provided on the side of the diaphragm facing the back plate, which can effectively prevent the diaphragm from sticking to the back plate when the vibration amplitude is large, ensuring the normal operation of the sensor and providing a larger detection range. At the same time, the anti-stick layer can effectively prevent dust entering the sensor capacitor cavity through the acoustic hole from adhering to the diaphragm, affecting the diaphragm's performance, and causing detection distortion and insensitivity. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a cross-sectional view of the MEMS sensor of the present invention.

[0021] Figure 2 This is an exploded cross-sectional view of the MEMS sensor of the present invention.

[0022] Figure 3 This is a schematic diagram of the diaphragm from a bottom view.

[0023] Figure 4 A structural diagram illustrating some steps in the fabrication of a MEMS sensor. Figure 1 .

[0024] Figure 5 A structural diagram illustrating some steps in the fabrication of a MEMS sensor. Figure 2 .

[0025] Figure 6 This is a flowchart illustrating the main steps of the MEMS sensor manufacturing method of the present invention.

[0026] Figure 7 This is a flowchart illustrating the main steps of the MEMS sensor manufacturing method of the present invention.

[0027] Figure 8 This is a flowchart illustrating the processing sequence of each step in the MEMS sensor manufacturing method of the present invention.

[0028] Figure label: 1. First support base; 10. First material layer; 11. Back cavity; 12. Seat ring groove; 2. Diaphragm mount; 21. Lower mount; 210. Second material layer; 211. First fitting and limiting part; 212. Second fitting and limiting part; 22. Upper mount; 220. Third material layer; 3. Diaphragm; 31. Lug; 311. Fitting and mounting part; 32. Notch; 33. Main membrane layer; 330. Fourth material layer; 34. Anti-stick layer; 340. Fifth material layer; 4. Second support; 40. Sixth material layer; 41. Cavity; 5. Backplate; 51. Insulating layer; 510. Seventh material layer; 52. Conductive layer; 520. Eighth material layer; 53. Acoustic hole. Detailed Implementation

[0029] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0030] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "top," "bottom," "inner," "outer," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0031] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, and "a number" means at least one, unless otherwise explicitly specified.

[0032] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0034] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention.

[0035] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0036] This invention provides a MEMS sensor and its manufacturing method. The MEMS sensor includes a first support 1, a diaphragm mount 2, a diaphragm 3, a second support 4, and a backplate 5.

[0037] Specifically, such as Figures 1 to 3 As shown, the first support 1 serves as the base, and its middle part has a back cavity 11 that runs vertically through it.

[0038] The diaphragm seat ring 2 is embedded in the seat ring groove 12 on one end side of the first support seat 1, and the middle cavity of the diaphragm seat ring 2 corresponds to the back cavity 11 of the first support seat 1.

[0039] The diaphragm 3 is a vibrating element, and its periphery is embedded in the diaphragm seat ring 2 and sealed to the diaphragm seat ring 2. The diaphragm 3 covers the back cavity 11 of the first support seat 1, that is, its projected area completely covers the back cavity 11 of the first support seat 1.

[0040] The second support 4 is disposed on the end of the first support 1 where the diaphragm 3 is disposed. The second support 4 is connected to the first support 1 and the diaphragm seat ring 2, and confines the diaphragm seat ring 2 between the first support 1 and the second support 4. The second support 4 has a cavity 41, which corresponds to the position of the diaphragm 3 and the back cavity 11 of the first support 1, and their projected areas overlap or partially overlap.

[0041] The back plate 5 is disposed on the end of the second support 4 away from the first support 1, and the back plate 5 completely covers the cavity 41. The back plate 5 has several sound holes 53, through which external sound can enter the cavity between the back plate 5 and the diaphragm 3, thereby causing the diaphragm 3 to vibrate and shift due to sound waves. A variable capacitor is formed between the back plate 5 and the diaphragm 3. When the diaphragm 3 shifts, the capacitance value changes accordingly. The conductive layer 52 of the back plate 5 transmits the (changing) capacitance value to the ASIC chip in real time. The ASIC chip converts the changing capacitance value into an electrical signal, thereby realizing the sensing, detection, and recording of sound.

[0042] The diaphragm mount 2 of the MEMS sensor is made of an elastic material and has elastic deformation capability. The diaphragm mount 2 is embedded between the first support 1 and the second support 4; at the same time, the periphery of the diaphragm 3 is connected to the diaphragm mount 2 by being embedded, which can give full play to the elastic deformation capability of the diaphragm mount 2 and prevent the diaphragm mount 2 and the diaphragm 3 from shifting or falling out.

[0043] This application, by setting a diaphragm seat ring 2 made of elastic material, makes the movement of the diaphragm 3 more sensitive and compliant, and makes the sensor's detection response more sensitive and accurate; and the diaphragm 3 and the diaphragm seat ring 2 are installed in a fitting manner, eliminating the anchoring connection of the diaphragm 3, which can effectively avoid or reduce the problem of stress concentration at the connection point of the diaphragm 3 and reduce the risk of damage to the diaphragm 3; at the same time, the setting of the diaphragm seat ring 2 also plays a role in silencing, damping vibration, and improving resonance.

[0044] In one embodiment, the diaphragm mount 2 includes a lower mount 21 and an upper mount 22 that are adapted to each other, and the periphery of the diaphragm 3 is embedded between the lower mount 21 and the upper mount 22. When the diaphragm 3 vibrates and shifts under the action of sound waves, its periphery can pull the diaphragm mount 2 to make a slight deformation, so as to release the stress at the connection part and play a buffering role.

[0045] like Figure 1 and Figure 2As shown, a seat ring groove 12 is provided circumferentially on the upper end face of the first support base 1 near the back cavity 11. The lower seat ring 21 is fitted into the seat ring groove 12 and is flush with the upper end face of the first support base 1. The bottom of the lower seat ring 21 is provided with a first fitting limiting part 211 that fits into the seat ring groove 12 of the first support base 1. Preferably, the first fitting limiting part 211 is located near the inner side of the bottom of the lower seat ring 21 and is a concave part. Correspondingly, the seat ring groove 12 is provided with a matching protrusion. By fitting together, the lower seat ring 21 can be limited, and mainly the displacement of the lower seat ring 21 towards the center can be restricted, which can effectively prevent the lower seat ring 21 from falling out when the diaphragm 3 vibrates too much. Preferably, the inner wall of the lower seat ring 21 is flush with the side wall of the back cavity 11 of the first support seat 1, or extends partially into the back cavity 11, that is, the lower side of the diaphragm 3 is only in contact with the lower seat ring 21 and does not directly make hard contact with the first support seat 1.

[0046] The lower retaining ring 21 has a second fitting and limiting part 212 on its upper part, which is adapted to the periphery of the diaphragm 3. Preferably, the second fitting and limiting part 212 is a concave part, which fits into the protrusion provided on the periphery of the diaphragm 3. The upper retaining ring 22 is covered on the periphery of the lower retaining ring 21 and the diaphragm 3. The upper retaining ring 22 and the lower retaining ring 21 cooperate to limit the connection of the periphery of the diaphragm 3. The second fitting and limiting part 212 fits into the diaphragm 3, and the upper retaining ring 22 covers and presses against the periphery of the diaphragm 3 and the lower retaining ring 21, thereby limiting the diaphragm 3 and preventing it from coming off during vibration. At the same time, it can also make the diaphragm 3 adapt to elastic buffering when subjected to vibration force, avoiding problems such as emergency concentration.

[0047] Optionally, the material of the diaphragm mount 2 includes one or more combinations of silicone, silicone resin, fluororubber, and styrene-butadiene rubber, and the diaphragm mount 2 has supporting and elastic deformation capabilities. Preferably, the elastic modulus of the material used to make the diaphragm mount 2 is controlled within the range of 0.8~2.5 MPa; more preferably, a material with an elastic modulus of 1.2~1.5 MPa is selected to prepare the diaphragm mount 2. This ensures that the diaphragm mount 2 has both good supporting capabilities and good elastic deformation and buffering capabilities, ensuring stable installation and reliable operation of the diaphragm 3.

[0048] like Figure 2 and Figure 3 As shown, the diaphragm 3 has a near-circular structure with multiple lugs 31 evenly distributed around its circumference, preferably arranged symmetrically in pairs. Each lug 31 has a protruding fitting and mounting portion 311 on its lower side, which fits and mounts with the second fitting and limiting portion 212 on the upper part of the lower seat ring 21. A smooth transition notch 32 separates adjacent lugs 31. The lugs 31 and the smooth transition notch 32 ensure more uniform stress distribution around the diaphragm 3, better tension between adjacent lugs 31, and prevent deformation, compression (stress concentration), and damage to the periphery.

[0049] The diaphragm 3 is installed inside the diaphragm seat 2. The diaphragm seat 2 completely covers the notch 32 around the diaphragm 3 and leaves room for deformation, ensuring that the diaphragm 3 and the diaphragm seat 2 are sealed together and that there will be no problem of seal failure when the diaphragm 3 vibrates.

[0050] In one implementation, such as Figure 1 , Figure 2 and Figure 5 As shown, the second support 4 covers the first support 1 and the diaphragm seat 2, and the second support 4, together with the diaphragm 3 and the back plate 5, forms a capacitor cavity. The cavity 41 of the second support 4 has a conical cavity portion, which is a conical cavity that expands from one end near the back plate 5 to the end near the diaphragm 3 / upper seat 22. This conical cavity portion allows the sound waves to act more concentratedly on the diaphragm 3, reducing sound wave loss and making the sensor detection more sensitive.

[0051] In one implementation, such as Figure 1 , Figure 2 , Figure 4 and Figure 5 As shown, the diaphragm 3 includes a main diaphragm layer 33 and an anti-adhesion layer 34, which is located on the side of the diaphragm 3 facing the back plate 5. Optionally, the anti-adhesion layer 34 is made of polytetrafluoroethylene and / or perfluoroethylene. The anti-adhesion layer 34 on the diaphragm 3 effectively prevents adhesion between the diaphragm 3 and the back plate 5 when the vibration amplitude is large, ensuring normal operation of the sensor and providing the sensor with a larger detection range (capacitance value variation range). Simultaneously, the anti-adhesion layer 34 effectively prevents dust entering the sensor's capacitance cavity through the acoustic hole 53 from adhering to the diaphragm 3, affecting its performance, and causing detection distortion and insensitivity.

[0052] Based on the same inventive objective, this application also provides a MEMS sensor manufacturing method for fabricating the aforementioned MEMS sensor. For example... Figures 4 to 8 As shown, the manufacturing method includes the following steps: S100, forming a first support base 1, the first support base 1 having a back cavity 11 extending vertically through the middle, and a seat ring groove 12 for setting the diaphragm seat ring 2 at the upper end.

[0053] S200, forming a diaphragm seat ring 2, which includes a matching lower seat ring 21 and an upper seat ring 22. The upper part of the lower seat ring 21 is provided with a second fitting limiting part 212 that is adapted to the fitting and mounting part 311 of the diaphragm 3.

[0054] S300, forming a diaphragm 3, the diaphragm 3 includes a main film layer 33 and an anti-sticking layer 34, that is, including forming a main film layer 33 and an anti-sticking layer 34.

[0055] S400, forming a second support 4, which has a through cavity 41 in the middle.

[0056] S500, forming a back plate 5, the back plate 5 including an insulating layer 51 and a conductive layer 52, and having a plurality of sound holes 53 extending vertically, that is, including a plurality of sound holes 53 forming on the back plate 5.

[0057] Further, in step S100, forming the first support base 1 specifically includes: S110, a first material layer 10 is provided as the first support base 1, and the first material layer 10 is etched to form a seat ring groove 12 for mounting the lower seat ring 21.

[0058] S120, etching the middle of the first material layer 10 to form a back cavity 11.

[0059] In step S200, forming the diaphragm mount 2 specifically includes: In step S210, an annular second material layer 210, serving as the lower seat ring 21, is formed within the seat ring groove 12 created in step S110. This second material layer 210 is etched to make it flush with the upper surface of the first support base 1, and a recessed second fitting and limiting portion 212 is formed on its upper side. This second fitting and limiting portion 212 is adapted to the fitting and mounting portion 311 of the diaphragm 3. Specifically, the second fitting and limiting portions 212 are evenly distributed circumferentially, matching the number of lugs 31 and fitting and mounting portions 311 of the diaphragm 3. The second fitting and limiting portions 212 can limit the radial and circumferential displacement of the diaphragm 3.

[0060] In step S220, a third material layer 220, serving as the upper ring 22, is formed on the first support 1, the lower ring 21, and the diaphragm 3. Then, the periphery of the third material layer 220 is etched to form the outer ring outline of the upper ring 22. This step S220 is performed after the diaphragm 3 is formed in step S300. The second material layer 210 and the third material layer 220 are preferably made of the same elastic material.

[0061] S230, and then the middle part of the third material layer 220 is etched to form the inner ring outline of the upper seat ring 22.

[0062] In step S300, forming the diaphragm 3 specifically includes: S310, a fourth material layer 330, serving as the main membrane layer 33 of the diaphragm 3, is provided on the first support 1 and the lower seat ring 21.

[0063] S320, a fifth material layer 340 is further provided on the fourth material layer 330 as an anti-stick layer 34.

[0064] S330, the fourth material layer 330 and the fifth material layer 340 are etched to form the lug 31 and the notch 32, and finally the diaphragm 3 is formed.

[0065] In step S400, forming the second support base 4 specifically includes: In step S410, a sixth material layer 40 serving as the second support 4 is formed on the first support 1, the upper ring 22, and the third material layer 220. The sixth material layer 40 is etched to form a cavity 41 in the second support 4, including forming a conical cavity within the cavity 41. Preferably, the etching process in step S410 is performed simultaneously with the etching process in step S230 on the middle part of the third material layer 220, that is, after etching the cavity 41 of the second support 4, the third material layer 220 is etched to form the inner ring contour of the upper ring 22.

[0066] The sixth material layer 40 is made of the same material as the first material layer 10, such as silicon oxide or silicon nitride.

[0067] In step S500, forming the backplate 5 specifically includes: S510, a seventh material layer 510 is provided on the second support 4 as an insulating layer 51 for the back plate 5.

[0068] S520, an eighth material layer 520 is provided on the seventh material layer 510 as a conductive layer 52 of the backplate 5.

[0069] S530, the seventh material layer 510 and the eighth material layer 520 are etched to form a number of acoustic holes 53, thereby completing the processing of the back plate 5.

[0070] The seventh material layer 510 is made of materials such as silicon nitride; the eighth material layer 520 and the fourth material layer 330 are made of the same material, such as polycrystalline silicon.

[0071] In one implementation, such as Figure 4 , Figure 5 and Figure 8 As shown, the MEMS sensor manufacturing method includes the following steps performed sequentially: S110, a first material layer 10 is provided as the first support base 1, and the first material layer 10 is etched to form a seat ring groove 12 for mounting the lower seat ring 21.

[0072] S210, an annular second material layer 210 serving as the lower seat ring 21 is provided in the seat ring groove 12 formed in step S110, and the second material layer is etched to make it flush with the upper end surface of the first support seat 1, and a concave second fitting limiting part 212 is formed on the upper side, which is adapted to the fitting mounting part 311 of the diaphragm 3.

[0073] S120, after the lower seat ring 21 is formed, the middle part of the first material layer 10 is etched to form the back cavity 11.

[0074] S310, a fourth material layer 330, serving as the main membrane layer 33 of the diaphragm 3, is provided on the first support 1 and the lower seat ring 21.

[0075] S320, a fifth material layer 340 is further provided on the fourth material layer 330 as an anti-stick layer 34.

[0076] S330, the fourth material layer 330 and the fifth material layer 340 are etched to form the lug 31 and the notch 32, and finally the diaphragm 3 is formed.

[0077] S220, a third material layer 220 serving as an upper ring 22 is provided on the first support 1, the lower ring 21 and the diaphragm 3, and then the periphery of the third material layer 220 is etched to form the outer ring outline of the upper ring 22.

[0078] S410, a sixth material layer 40 serving as a second support 4 is provided on the first support 1, the upper ring 22 / third material layer 220, and the sixth material layer 40 is etched to form a cavity 41 of the second support 4, including forming a conical cavity within the cavity 41.

[0079] S230, and then the middle part of the third material layer 220 is etched to form the inner ring outline of the upper seat ring 22.

[0080] S510, a seventh material layer 510 is provided on the second support 4 as an insulating layer 51 for the back plate 5.

[0081] S520, an eighth material layer 520 is provided on the seventh material layer 510 as a conductive layer 52 of the backplate 5.

[0082] S530, the seventh material layer 510 and the eighth material layer 520 are etched to form a number of acoustic holes 53, thereby completing the processing of the back plate 5.

[0083] This MEMS sensor has a simple structure and reasonable configuration. Its manufacturing method is simple, easy to process, and low in cost.

Claims

1. A MEMS sensor, characterized in that, include: The first support has a back cavity; A diaphragm seat is embedded on one end of the first support base, and the middle part of the diaphragm seat corresponds to the back cavity; The diaphragm is embedded in the diaphragm seat ring around its periphery, correspondingly covering the back cavity; The second support has a cavity. The second support is disposed on the end of the first support where the diaphragm is located. The cavity corresponds to the diaphragm and the back cavity. A back plate with several sound holes is provided on it. The back plate is located on the side of the second support base away from the first support base and covers the cavity. The diaphragm housing is made of an elastic material.

2. The MEMS sensor according to claim 1, characterized in that, The diaphragm housing includes a matching lower housing and an upper housing; the periphery of the diaphragm is embedded between the lower housing and the upper housing.

3. The MEMS sensor according to claim 2, characterized in that, The lower seat ring is embedded in the seat ring groove of the first support seat. The bottom of the lower seat ring is provided with a first fitting limiting part adapted to the first support seat, and the upper part of the lower seat ring is provided with a second fitting limiting part adapted to the diaphragm. The upper seat ring is covered on the lower seat ring and on the periphery of the diaphragm.

4. The MEMS sensor according to any one of claims 1 to 3, characterized in that, The diaphragm mount is made of one or more of silicone, silicone resin, fluororubber, and styrene-butadiene rubber, and the elastic modulus of the diaphragm mount is 0.8~2.5MPa.

5. The MEMS sensor according to claim 3, characterized in that, The diaphragm is provided with a plurality of lugs evenly distributed around its circumference, and there is a smooth transition notch between adjacent lugs; the lower side of the lug is provided with a fitting and mounting part, which is adapted to fit and fit with the second fitting and limiting part; the diaphragm seat completely covers the notch.

6. The MEMS sensor according to claim 1, characterized in that, The second support is disposed on the first support and the diaphragm seat ring; the cavity of the second support has a conical cavity portion, which expands from the end near the back plate to the end near the diaphragm.

7. The MEMS sensor according to claim 1, characterized in that, The diaphragm has an anti-sticking layer on the side facing the back plate.

8. A method for manufacturing a MEMS sensor, characterized in that, Includes the following steps: S100, forming a first support seat, the first support seat having a seat groove and a back cavity; S200, forming a diaphragm seat ring, the diaphragm seat ring including a lower seat ring and an upper seat ring, the upper part of the lower seat ring being provided with a second fitting and limiting part in the circumferential direction; S300, forming a diaphragm, the diaphragm including a main diaphragm layer and an anti-adhesion layer, the diaphragm having lugs and notches; S400, forming a second support base, the second support base having a cavity; S500, forming a back plate, the back plate having acoustic holes.

9. The MEMS sensor manufacturing method according to claim 8, characterized in that: Step S100 specifically includes: S110, a first material layer is provided as a first support base, and the first material layer is etched to form the seat groove; S120, etching the first material layer to form the back cavity; Step S200 specifically includes: S210, a second material layer serving as a lower seat ring is provided in the seat ring groove, and the second material layer is etched to form the second fitting and limiting portion; S220, a third material layer serving as an upper ring is provided on the first support, the lower ring, and the diaphragm, and the periphery of the third material layer is etched to form the outer ring outline of the upper ring; S230, Etching the middle part of the third material layer to form the inner ring outline of the upper seat ring; Step S300 specifically includes: S310, a fourth material layer serving as the main diaphragm layer is provided on the first support and the lower seat ring; S320, a fifth material layer is provided on the fourth material layer as an anti-adhesion layer for the diaphragm; S330, etching the fourth and fifth material layers to form the lugs and notches; Step S400 specifically includes: S410, a sixth material layer is provided as a second support, and the sixth material layer is etched to form a cavity for the second support; Step S500 specifically includes: S510, a seventh material layer serving as a backplate insulation layer is provided on the second support; S520, an eighth material layer is provided on the seventh material layer as a backplate conductive layer; S530, etching the seventh and eighth material layers to form acoustic holes.

10. The MEMS sensor manufacturing method according to claim 9, characterized in that, The method includes the following steps performed sequentially: S110, S210, S120, S310, S320, S330, S220, S410, S230, S510, S520, and S530.

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