A MEMS microphone

Abstract

An embodiment of the present application discloses a microelectromechanical microphone. The microelectromechanical microphone includes: a substrate, on which a sound hole is formed; a diaphragm, which is disposed on the substrate and covers the position corresponding to the sound hole. The diaphragm includes a diaphragm main body and a relief valve. The relief valve includes a valve flap and a relief hole formed in the diaphragm main body. The valve flap is connected to the diaphragm main body in a movable manner and extends into the relief hole; a back plate, which is disposed on the substrate, is arranged in parallel with the diaphragm, and a predetermined gap is left between the back plate and the diaphragm. A plurality of support protrusions are provided on the surface of the back plate facing the diaphragm, and the height of the support protrusions is less than the predetermined gap; the support protrusions are at least distributed at positions corresponding to the relief valve, and the support protrusions are used to abut against the edge of the relief hole and / or the connection between the valve flap and the diaphragm main body.

Description

Technical Field

[0001] This application belongs to the field of microelectromechanical technology. Specifically, this application relates to a microelectromechanical microphone. Background Art

[0002] With the rapid development of electronic technology, MEMS (Micro-Electro-Mechanical System) microphones have been increasingly widely used due to their advantages such as small size, convenient SMT (Surface Mount Technology) installation, high temperature resistance, good stability, high automation level, and suitability for mass production.

[0003] Among them, MEMS microphone products include MEMS chips based on capacitance detection. The capacitance of the MEMS chip will generate corresponding vibrations with different sound vibrations, thereby generating a changing electrical signal to achieve the function of sound-electricity conversion.

[0004] The diaphragm of the MEMS microphone is very thin, and when it is affected by air flow impact, collision, etc., the diaphragm may be torn, damaged, or cracked. In the prior art, those skilled in the art have tried to add various structures to the diaphragm and back plate of the MEMS microphone to provide support, protection, pressure relief, etc. for the diaphragm. However, due to the fact that such improved structures cannot fully play the role of pressure relief and are prone to bringing other weak structures to the diaphragm, the problem of diaphragm rupture still occurs. Summary of the Invention

[0005] An object of an embodiment of this application is to provide an improved microelectromechanical microphone.

[0006] The microelectromechanical microphone includes:

[0007] A substrate, on which a sound hole is formed;

[0008] A diaphragm, which is arranged on the substrate, covers the position corresponding to the sound hole, and the diaphragm includes a diaphragm main body and a relief valve. The relief valve includes a valve flap and a relief hole opened on the diaphragm main body. The valve flap is connected to the diaphragm main body in a movable manner and extends into the relief hole;

[0009] A back plate, which is arranged on the substrate, is arranged in parallel with the diaphragm, and a predetermined gap is left between the back plate and the diaphragm. A plurality of support protrusions are arranged on the surface of the back plate facing the diaphragm, and the height of the support protrusions is less than the predetermined gap;

[0010] The support protrusions are at least distributed at positions corresponding to the relief valve, and the support protrusions are used to abut against the edge of the relief hole and / or the connection between the valve flap and the diaphragm main body.

[0011] Optionally, along the surface of the backplate, the support protrusions have a continuously extending structure.

[0012] Optionally, the support protrusions are discrete columnar structures.

[0013] Optionally, the support protrusions are provided at positions corresponding to the connection between the valve flap and the diaphragm body, and the support protrusions extend and are distributed along the edges of the air discharge holes on both sides from the position where the valve flap is connected to the diaphragm body.

[0014] Optionally, the support protrusions extend and are distributed on the backplate in a semi - enclosed form.

[0015] Optionally, the support protrusions extend and are distributed on the backplate in a ring - shaped form.

[0016] Optionally, the support protrusions include a first protrusion and a second protrusion. The first protrusion is distributed at a position corresponding to the air release valve, and the second protrusion is distributed at positions corresponding to other regions of the diaphragm body.

[0017] Optionally, the height of the first protrusion is greater than that of the second protrusion, and the height of the first protrusion is less than 0.8 times the predetermined gap;

[0018] In a direction parallel to the surface of the backplate, the radial dimension of the self - structure of the first protrusion is greater than that of the self - structure of the second protrusion.

[0019] Optionally, the support protrusions are of a multi - layer structure, and the support protrusions include a surface layer located on the surface and a core part located inside.

[0020] Optionally, the support protrusions are silicon nitride and / or silicon oxide.

[0021] One technical effect of the embodiments of the present application is that the support protrusions form a supporting effect on the air release valve, improving the function of the air release valve to open and release air. Further, the support protrusions protect the structure of the air release valve.

[0022] Other features and advantages of the present application will become clear from the following detailed description of the exemplary embodiments of the present application with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings incorporated in and constituting a part of this specification illustrate embodiments of the present application and, together with the description, are used to explain the principles of the present application.

[0024] Figure 1 It is a schematic side cross - sectional view of a micro - electromechanical microphone provided by an embodiment of the present application;

[0025] Figure 2Schematic side sectional view of the MEMS microphone provided by the embodiment of the present application;

[0026] Figure 3 Partial side view of the MEMS microphone provided by the embodiment of the present application;

[0027] Figure 4 Schematic partial top view of the MEMS microphone provided by the embodiment of the present application;

[0028] Figure 5 Schematic partial top view of the MEMS microphone provided by the second embodiment of the present application;

[0029] Figure 6 Schematic partial top view of the MEMS microphone provided by the third embodiment of the present application;

[0030] Figure 7 Schematic partial top view of the MEMS microphone provided by the fourth embodiment of the present application;

[0031] Figure 8 Schematic partial top view of the MEMS microphone provided by the fifth embodiment of the present application;

[0032] Figure 9 Schematic partial top view of the MEMS microphone provided by the sixth embodiment of the present application;

[0033] Figure 10 Schematic side sectional view of the support protrusion provided by the embodiment of the present application. Detailed implementation manners

[0034] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that: Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and values set forth in these embodiments do not limit the scope of the present application.

[0035] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0036] Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be considered as part of the specification.

[0037] In all the examples shown and discussed herein, any specific values should be construed as merely exemplary and not as limitations. Thus, other examples of the exemplary embodiments may have different values.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, further discussion thereof is not required in subsequent drawings.

[0039] The present technical solution provides a microelectromechanical microphone. The structure of the diaphragm and the backplate of the microphone is improved, so that the air release valve on the diaphragm can be opened more effectively when subjected to an air flow impact, realizing pressure relief and reducing the risk of damage to the diaphragm.

[0040] As Figure 1 shown, the microelectromechanical microphone includes a substrate 1, a diaphragm 2, and a backplate 3. The substrate 1 is a substrate structure of the microelectromechanical microphone, which is used to carry other structural components. A sound hole 11 is formed on the substrate 1, and the sound hole 11 is used for sound to pass through and be transmitted to the components of the microelectromechanical microphone, so that the microelectromechanical microphone can convert sound vibration into mechanical vibration and electrical signals.

[0041] The diaphragm 2 is disposed on the substrate 1. The diaphragm 2 can be directly disposed on the substrate 1 or indirectly fixed on the substrate 1 through an isolation layer, a support layer, etc. The substrate 1 is used to provide support for components such as the diaphragm 2 and the backplate 3. The present application does not limit whether the substrate 1 supports the diaphragm 2 directly or indirectly. The diaphragm 2 covers the sound hole 11. As Figure 1 shown, the sound vibration transmitted from the sound hole 11 can act on the diaphragm 2, thereby driving the diaphragm 2 to vibrate.

[0042] As Figures 1 to 3 shown, the diaphragm 2 includes a diaphragm body 21 and an air release valve. The diaphragm body 21 is the overall structure of the diaphragm, which represents the main part of the thin film in the present application. It has an edge region sandwiched between structural layers and a suspended region extending above the sound hole 11. The air release valve refers to a valve-like structure disposed on the diaphragm body 21, which can be opened to a certain extent to release pressure in time when the diaphragm 2 is subjected to a strong air flow impact, reducing the risk of diaphragm rupture.

[0043] The air release valve includes a valve flap 23 and an air release hole 22. The air release hole 22 is opened on the diaphragm body 21, and the air release hole 22 is a through hole on the diaphragm body 21. As Figures 1 to 3 shown. The valve flap 23 is entirely located at the air release hole 22. When it is flush with the air release hole 22, it can block a large part of the air release hole 22 or cover the entire air release hole 22. The valve flap 23 is connected to the diaphragm body 21, that is, the valve flap 23 is connected to the diaphragm body 21 at the edge of the air release hole 22. As Figure 3As shown, this connection is the connection portion 24. The connection between the valve flap 23 and the diaphragm body 21 is flexible and movable. When impacted by airflow, the valve flap 23 can deflect upward or downward and open, thereby opening the air leakage hole 22 and allowing the air flow to quickly pass through the air leakage hole 22. Through the movable connection between the valve flap 23 and the diaphragm body 21, the valve flap 23 can extend into the air leakage hole 22 and open and close relative to the air leakage hole 22.

[0044] The back plate 3 is arranged on the substrate 1. Figure 1 In the illustrated embodiment, the back plate 3 is disposed above the diaphragm 2 via a support structure 4. The back plate 3 is relatively parallel to the diaphragm 2, with a predetermined gap between them. The predetermined gap allows space for the diaphragm 2 to vibrate and also allows space for the valve flap 23 on the diaphragm 2 to open.

[0045] The back plate is provided with a plurality of supporting protrusions, such as Figures 1 to 3 As shown. The support protrusion is formed on the side of the back plate facing the diaphragm 2. At least a part of the support protrusion is distributed at the position corresponding to the air release valve. This includes: a support protrusion corresponding to the edge position of the air release hole; and / or a support protrusion corresponding to the connection portion 24 between the valve flap and the diaphragm body 21. These support protrusions are used to stop the edge of the air release hole 22 and / or the connection portion 24 between the valve flap 23 and the diaphragm body 21. The height of the support protrusion is less than the height of the predetermined gap, such as Figure 1 As shown, under normal circumstances, the diaphragm 2 will not contact the supporting protrusion. The diaphragm 2 will not contact the supporting protrusion when it is not subjected to force or is vibrated by sound during normal operation. Sufficient space will be left between the supporting protrusion and the diaphragm 2.

[0046] When the diaphragm 2 is subjected to abnormal impact, such as falling, abnormal blowing, etc. Figure 2 As shown, the diaphragm 2 will be pushed upward by the impact of the airflow. In this case, the end of the support protrusion located at the air release valve will touch the edge of the air release hole 22, or touch the connecting portion 24. After the support protrusion supports the edge of the air release hole 22 or the connecting portion 24, these two parts of the structure will not be able to continue to move upward with the impact of the airflow. The valve flap 23 can move upward more easily under the action of the airflow, thereby being lifted and opened. This design method helps the air release valve to open under the impact of large airflow and achieve the air release effect more quickly. The main purpose of arranging the support protrusion in the above-mentioned two position areas is to fix the structure around the valve flap, so that the air flow effect can be concentrated in the air release hole 22, which is more convenient for lifting and opening the valve flap. The valve flap has an obvious open state, and the pressure on the diaphragm can be significantly reduced.

[0047] This technical solution provides a variety of implementation methods, so that in different structural forms, the diaphragm structure around the valve flap 23 can be effectively stopped to assist the valve flap 23 in opening. Figure 4 , Figure 6 and Figure 8 In the illustrated embodiment, the support protrusion may be a continuously extending structure, that is, the support protrusion is wall-shaped and extends a certain length on the back plate 3 according to a pre-designed shape. Figure 4 , Figure 6 and Figure 8 All of them are simple top-view schematic diagrams of the combination of the back plate 3 and the diaphragm. Designing the support protrusion to be in a continuously extended form can, on the one hand, implement a uniform top-stopping effect on the diaphragm structure around the valve flap 23, thereby optimizing the opening effect of the valve flap 23. On the other hand, the continuously extended support protrusion can protect the diaphragm. When the diaphragm 2 is impacted by the airflow, the support protrusion supports the diaphragm around the valve flap 23, which increases the contact area between the support protrusion and the diaphragm and reduces the possibility of stress concentration on the diaphragm. The possibility of the diaphragm being damaged by collision with the support protrusion is extremely low. Moreover, the diaphragm can reduce the occurrence of local large-scale bending and deformation through the support and buffering effect of the continuously extended support protrusion, and the possibility of damage to the diaphragm itself is greatly reduced.

[0048] Practical testing has shown that installing a support protrusion at the corresponding location of the air release valve effectively reduces the stress on the diaphragm, allowing air to escape more efficiently through the air release valve. Comparing the design with and without the support protrusion at the air release valve, the pressure on the diaphragm was reduced by 30%.

[0049] In another embodiment of the present invention, Figure 5 , Figure 7 and Figure 9 In the illustrated embodiment, the support protrusions may be discretely distributed columnar structures. The multiple discrete support protrusions arranged around the valve flap 23 also support and stabilize the diaphragm around the valve flap 23, thereby concentrating the impact force of the strong airflow on the valve flap 23, allowing the valve flap 23 to open more smoothly and providing pressure relief. Figure 5 , Figure 7 and Figure 9 These are all simplified top views of the back plate 3 and the diaphragm assembly, with respect to the discrete distribution positions of the supporting protrusions. Figure 5 , Figure 7 and Figure 9 Different segment forms are given respectively. Different segment forms show different effects in terms of mechanical properties and the function of assisting the valve flap 23 to open, and have different protective effects on the diaphragm.

[0050] Compared to Figure 4 ,Figure 6 and Figure 8 In the embodiment shown, in the embodiment where the supporting protrusions are designed as columnar structures and are discretely distributed, the space occupied by the supporting protrusions is less, the influence on the capacitive structure of the MEMS microphone is smaller, and enough capacitance value can be reserved between the diaphragm and the back plate 3. Further, the possibility that the discretely distributed supporting protrusions interfere with the normal vibration of the diaphragm is small. During vibration, the diaphragm will naturally generate a certain amount of bending deformation. If the supporting protrusions occupy a large and wide space, the vibration of the diaphragm may collide with the supporting protrusions, which will have some impact on the sound performance of the microphone. However, the discrete supporting protrusions distributed around the valve flap 23 occupy relatively less lateral space and are not likely to cause the above risks.

[0051] Further, the supporting protrusions are in different positions relative to the valve flap 23, and can also play different roles in the opening condition of the valve flap 23. In the technical solutions as shown in Figure 5 and Figure 6 the supporting protrusions are arranged at positions corresponding to the connection between the valve flap 23 and the diaphragm main body 21. Further, as shown in Figure 3 the supporting protrusions located on the left side of the valve flap 23 can indicate that the supporting protrusions are at the position where the valve flap 23 is connected to the diaphragm main body 21. The valve flap 23 can be lifted relative to the diaphragm main body 21, and the supporting protrusions located at this position can play a fulcrum role relative to the diaphragm main body 21 and the valve flap 23. When the diaphragm floats upward and touches the supporting protrusions, the diaphragm main body will be blocked by the supporting protrusions and is not easy to move further, while the valve flap on the other side of the supporting protrusions is in a free state and is more likely to deflect and open around the fulcrum under the impact force.

[0052] Further, the supporting protrusions can also extend from the position where the valve flap 23 is connected to the diaphragm main body to both sides and continuously extend along the edge of the air vent hole 22. As shown in Figure 5 and Figure 6 the supporting protrusions can extend for a certain distance, and then form a supporting effect on both sides and around the connecting part 24 between the valve flap 23 and the diaphragm main body 21. Such a design is more helpful to form a complete and stable support for the connecting part 24 between the valve flap 23 and the diaphragm main body, so as to form a good fulcrum effect and improve the opening speed and opening angle of the valve flap 23.

[0053] Optionally, the supporting protrusions can extend in a semi-surrounding form on the back plate 3, as shown in Figure 5 and Figure 6As shown. The so-called semi-surrounding extended distribution means that the projection of the support protrusion on the diaphragm can form a distribution form that semi-surrounds the vent hole 22 around the edge of the vent hole 22. When the diaphragm touches the support protrusion, the support protrusion can support and stop the about half-circle structure of the vent hole 22 to ensure that the vent hole 22 does not deform or bend as much as possible under the impact of the large airflow, so that the airflow can effectively push open the valve flap 23. In particular, as Figure 5 and Figure 6 shown, the support protrusions forming the semi-surrounding extended distribution pass through the connecting portion 24 between the valve flap 23 and the diaphragm body 21. That is, the support protrusions can support the root of the valve flap 23. The root of the valve flap 23 and the diaphragm body 21 on both sides thereof can be supported, and the valve flap 23 can open more effectively under the impact of the airflow without deforming the root of the valve flap 23 and the surrounding structure of the root of the valve flap 23 together.

[0054] For the discrete support protrusions as shown in Figure 5 and the continuously extended support protrusions as shown in Figure 6 shown, the technical solution can design them into a semi-surrounding distribution form.

[0055] Optionally, in other embodiments, the support protrusions can also extend in a ring-shaped distribution on the back plate 3, as shown in Figure 4 and Figure 7 shown. The so-called form that the support protrusions extend in a ring-shaped distribution means that the projection of the support protrusions on the diaphragm surrounds the edge of the vent hole 22 in a circle. That is, when the diaphragm approaches the back plate 3 and contacts the support protrusions, the ring-shaped distributed support protrusions can stop and limit the entire edge of the vent hole. The diaphragm structure around the vent hole cannot continue to move upward. Relatively, the valve flap located in the middle of the vent hole can be better lifted upward relative to the vent hole. The support protrusions distributed in a ring shape relative to the vent hole have a stronger protective effect on the diaphragm, and the diaphragm is less likely to shake or vibrate after contacting the support protrusions, especially the area around the vent hole can be stably supported.

[0056] In the embodiment shown in Figure 4 shown, the support protrusions are continuously extended solid structures, which enclose a structure similar to the side wall of a cylinder or a quadrangular prism on the lower side of the back plate 3. This structure has high reliability, provides a more stable support effect, and the diaphragm is not easily damaged due to collision with the support protrusions. In addition, during the processing and forming process, the continuously extended integral support protrusions are easier to process and form, and the process difficulty is lower.

[0057] In Figure 7In the illustrated embodiment, the support protrusions are discrete and independent columnar structures. A plurality of columnar support protrusions are arranged in a ring shape with a small distance between each other, and the plurality of support protrusions are distributed around the edge of the air vent 22. The advantage of this design is that there are gaps between the individual columnar support protrusions, and the existence of these gaps facilitates gas flow. In the case of a large airflow impacting the diaphragm, after the airflow passes through the air vent 22, it can diffuse through the gaps between the columnar support protrusions, and then the airflow can flow out better through the sound holes 33 formed on the back plate 3, ultimately achieving the effect of discharging pressure. Therefore, using discrete support protrusions can more effectively disperse the airflow and the pressure.

[0058] In a further combined embodiment, the technical solution can combine the above-mentioned continuously extending support protrusions with the discretely distributed support protrusions, thereby providing a more comprehensive effect for relieving pressure on the diaphragm.

[0059] In the embodiment as Figure 8 shown, the support protrusion includes three sections of continuously extending wall-like structures. One section of the support protrusion corresponds to the connection portion 24 between the valve flap 23 and the diaphragm body 21, and this section of the support protrusion extends horizontally across the entire connection portion 24. In this way, the bar-shaped extending support protrusion can well play a fulcrum role for the valve flap 23 and guide the valve flap 23 to open. As Figure 8 shown, in the position areas corresponding to both sides of the valve flap 23, a support protrusion is respectively formed on the back plate 3, and these two support protrusions can respectively form a stop and support for the edges of the air vents 22 on both sides of the valve flap 23. In this way, when the diaphragm is impacted and contacts the support protrusion upward, the diaphragm bodies 21 on both sides of the valve flap 23 will not continue to move upward or deform under the action of the airflow. In this case, the valve flap 23 is lifted by the airflow, and the amplitude of its opening of the air vent 22 can be guaranteed. And since the three sections of support protrusions are not connected to each other, and there is no support protrusion corresponding to the edge of the air vent 22 far from the connection portion 24. Therefore, the airflow can form a dispersed and flowing effect through the gaps between the support protrusions on the diaphragm side. This way is also more conducive to the dispersion of pressure.

[0060] In the embodiment as Figure 9 shown, the support protrusion includes three pairs of columnar support protrusions distributed at different positions, and each pair of support protrusions includes two independent columnar support protrusions, as Figure 9As shown in the figure. The distance between these two columnar support protrusions is relatively close, but they are still independent of each other. The interval distance between each pair of support protrusions is relatively far, and their positions are also different relative to the valve flap 23 and the air vent 22. One pair of support protrusions is located at the connecting portion 24 between the valve flap 23 and the diaphragm body 21, which is used to play the role of a fulcrum to assist the valve flap 23 to bend at the support protrusion relative to the diaphragm body 21, so as to open the air vent 22. On both sides of the valve flap 23, a pair of support protrusions are respectively arranged. The support protrusions on both sides can support and limit the edges of the air vents 22 on both sides of the valve flap 23. Two mutually close support protrusions form a pair of support protrusions. The relative distance between these two support protrusions is relatively close, and a good limiting effect can be provided at a relatively concentrated position. The relative distances between the three pairs of support protrusions are relatively far, and most of the space between the air vent 22 of the diaphragm and the back plate 3 is not occupied by the support protrusions. In this way, after the air passes through the air vent 22, it can be quickly dispersed between the diaphragm and the back plate 3, and then flow out from the sound holes 33 opened on the back plate. When the air flows horizontally, it is basically not affected by the resistance of the support protrusions. This design method can not only use two or more centrally arranged support protrusions to support the diaphragm in a specific area, but also minimize the space occupied by the support protrusions and reduce the resistance of the air flowing horizontally. In particular, the less the structure occupying the space between the diaphragm and the back plate, the smaller the impact on the capacitance performance between the two, which helps to maintain the electroacoustic conversion performance of the microphone.

[0061] Optionally, as Figure 1 and Figure 2 shown, in this technical solution, the support protrusions may include two types of support protrusions, one of which is the first protrusion 32, and the other is the second protrusion 31. In the above embodiment, the support protrusions arranged at the corresponding positions of the air release valve are all the first protrusions 32. The structure and shape of the second protrusion 31 are different from those of the first protrusion 32, and the second protrusion 31 is not distributed at the positions corresponding to the air release valve. The height of the second protrusion 31 is less than the height of the first protrusion 32, and the shape of the second protrusion 31 is generally a thin cylinder with a relatively small diameter / height ratio. The second protrusion 31 is distributed at positions not corresponding to the air release valve, that is, at positions corresponding to other areas of the diaphragm body 21 where there are no air vents 22.

[0062] As described above, the first protrusion 32 is used to support and stop the air leakage holes 22 and the connecting part 24 on the diaphragm, and assist the valve flap 23 to fully open. The second protrusion 31 is used to prevent the diaphragm from colliding with and adhering to the lower surface of the back plate due to excessive floating. Since the thickness of the diaphragm is very thin and its diameter-to-thickness ratio is extremely large, if the diaphragm touches the back plate as a whole due to excessive upward floating, it may be completely adsorbed and adhered to the back plate due to the action of surface tension, and the diaphragm and the back plate cannot be separated. This will seriously affect the performance of the microphone. Even if the second protrusion 31 is provided on the back plate so that the corresponding position of the air release valve can be supported, since the space and area occupied by the air release valve are small, most areas of the diaphragm body 21 may still face the above-mentioned adhesion risk. Therefore, by providing the first protrusion 32 in other areas of the back plate, the diaphragm body 21 can be stopped when the diaphragm moves upward significantly, so that the diaphragm body 21 cannot be attached to the lower surface of the back plate as a whole.

[0063] As Figure 1 and Figure 2 shown, a predetermined gap is formed between the diaphragm and the back plate 3 through the support structure 4. This predetermined gap is a safe space for the diaphragm to float up and down. The vibration amplitude generated by the diaphragm due to sound vibration is relatively small and only occupies a small part of the height of the predetermined gap. In this regard, the heights of the first protrusion 32 and the second protrusion 31 should be less than the height of the predetermined gap, and sufficient vibration space should be left for the diaphragm. Optionally, the height of the first protrusion 32 is less than 0.8 times the height of the predetermined gap, that is, the first protrusion 32 leaves at least 20% of the height of the predetermined gap for the diaphragm as the height space for normal vibration. The heights of the first protrusion 32 and the second protrusion 31 refer to the lengths that the protrusions extend downward from the lower surface of the back plate 3.

[0064] Optionally, the height of the second protrusion 31 can be less than the height of the first protrusion 32, and it can be less than 0.4 times the height of the predetermined gap. For example, the height of the second protrusion 31 can be 0.3 times the height of the predetermined gap, or 0.2 times the height of the predetermined gap.

[0065] Optionally, along the direction parallel to the surface of the back plate 3, that is, as Figure 1 and Figure 2In the horizontal direction shown, the radial dimension of the self-structure of the first protrusion 32 is greater than that of the self-structure of the second protrusion 31. For example, both the first protrusion 32 and the second protrusion 31 are cylindrical structures, and the diameter of the first protrusion 32 is greater than that of the second protrusion 31. Or, the first protrusion 32 is a plate-like structure, the second protrusion 31 is a cylindrical structure, and the width dimension of the first protrusion 32 is greater than the diameter of the second protrusion 31. The lower end face area of the first protrusion 32 is greater than that of the second protrusion 31. The structure of the second protrusion 31 is widely distributed on the back plate 3. If the structure size is too large, it will seriously affect the capacitance of the microphone. Moreover, the second protrusion 31 usually does not play a role and only serves as an insurance in abnormal situations. Therefore, the size of the second protrusion 31 is preferably relatively small to minimize the space it occupies inside the microphone.

[0066] Optionally, as Figure 10 shown, the support protrusion can be a multi-layer structure. For example, the outer surface on the lower side of the first protrusion 32 is made of silicon nitride material or silicon oxide material, and the inner layer is made of polysilicon material. Making the support protrusion with multi-layer materials can better meet the requirements of practical applications. The outer layer material of the support protrusion can be insulating and has better strength, better ability to handle impacts and collisions, and is not easily deformed, cracked, or powdered. The inner layer material of the support protrusion can adopt the main material of the back plate 3, making it easier to form the support protrusion when processing the back plate 3 and minimizing the addition of excessive processing steps for processing the back plate 3.

[0067] Optionally, the support protrusion can be made of materials such as silicon nitride, silicon oxide, polysilicon, etc. One of these materials can be selected, or multiple materials can be selected to form a multi-layer structure.

[0068] For the back plate, as described above, sound holes 33 can also be provided thereon. As Figures 1 to 3 shown, optionally, the sound holes 33 can be provided at positions corresponding to the air release valve. That is, the sound holes 33 correspond to the air release holes 22 in position. After the air flow lifts the valve flap 23 upward from below the diaphragm, a large part of it can directly flow out from the sound holes 33 on the back plate 3, effectively relieving pressure. The sound holes 33 can cooperate with the support protrusion and the first protrusion. The first protrusion surrounds the sound holes 33 and the air release holes 22, and the size of the valve flap 23 can be smaller than that of the sound holes 33. The support protrusion can form a role similar to a channel between the air release holes 22 and the sound holes 33 to guide the air flow to exhaust and relieve pressure.

[0069] Although some specific embodiments of the present application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and not for limiting the scope of the present application. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A microelectromechanical microphone, characterized in that, Comprising: A base on which sound holes are formed; A diaphragm disposed on the base, the diaphragm covering a position corresponding to the sound hole. The diaphragm includes a diaphragm body and a deflation valve. The deflation valve includes a valve flap and a deflation hole formed in the diaphragm body. The valve flap is connected to the diaphragm body in a movable manner, and the valve flap extends into the deflation hole; A back plate disposed on the base, the back plate being arranged in parallel with the diaphragm, a predetermined gap being left between the back plate and the diaphragm. A plurality of support protrusions are provided on a surface of the back plate facing the diaphragm, and the height of the support protrusions is less than the predetermined gap; The support protrusions are at least distributed at positions corresponding to the deflation valve, and the support protrusions are used to abut against the edge of the deflation hole and the connection position between the valve flap and the diaphragm body; The support protrusions are provided at positions corresponding to the connection between the valve flap and the diaphragm body, and the support protrusions extend along the edge of the deflation hole from the connection position between the valve flap and the diaphragm body to both sides; the support protrusions extend and distribute on the back plate in a semi-surrounding form. The semi-surrounding form of the extension and distribution means that the projection of the support protrusions on the diaphragm can form a semi-surrounding distribution form around the edge of the deflation hole.

2. The MEMS microphone according to claim 1, characterized in that, Along the surface of the back plate, the support protrusions are in a continuously extending structure; the support protrusions are in a wall shape and extend a certain length on the back plate according to a preset shape.

3. The MEMS microphone according to claim 1, wherein, The support protrusions are discrete columnar structures.

4. A microelectromechanical microphone, characterized in that, Comprising: A base on which sound holes are formed; A diaphragm disposed on the base, the diaphragm covering a position corresponding to the sound hole. The diaphragm includes a diaphragm body and a deflation valve. The deflation valve includes a valve flap and a deflation hole formed in the diaphragm body. The valve flap is connected to the diaphragm body in a movable manner, and the valve flap extends into the deflation hole; A back plate disposed on the base, the back plate being arranged in parallel with the diaphragm, a predetermined gap being left between the back plate and the diaphragm. A plurality of support protrusions are provided on a surface of the back plate facing the diaphragm, and the height of the support protrusions is less than the predetermined gap; The support protrusions are at least distributed at positions corresponding to the deflation valve, and the support protrusions are used to abut against the edge of the deflation hole and the connection position between the valve flap and the diaphragm body; The support protrusions are provided at positions corresponding to the connection between the valve flap and the diaphragm body, and the support protrusions extend along the edge of the deflation hole from the connection position between the valve flap and the diaphragm body to both sides; The support protrusions are discrete columnar structures, and the support protrusions extend and distribute on the back plate in a circular form. The circular form of the extension and distribution means that the projection of the support protrusions on the diaphragm surrounds the edge of the deflation hole in a circle.

5. The MEMS microphone according to claim 1 or 4, characterized in that, The support protrusions include a first protrusion and a second protrusion. The first protrusion is distributed at a position corresponding to the air release valve, and the second protrusion is distributed at a position corresponding to other regions of the diaphragm body.

6. The MEMS microphone according to claim 5, characterized in that, The height of the first protrusion is greater than that of the second protrusion, and the height of the first protrusion is less than 0.8 times the predetermined gap; the height of the first protrusion is the length that the first protrusion extends downward from the lower surface of the back plate; the height of the second protrusion is the length that the second protrusion extends downward from the lower surface of the back plate; In the direction parallel to the surface of the back plate, the radial dimension of the self-structure of the first protrusion is greater than that of the self-structure of the second protrusion.

7. The MEMS microphone according to claim 1 or 4, characterized in that, The support protrusion is a multi-layer structure, and the support protrusion includes a surface layer located on the surface and a core portion located inside.

8. The MEMS microphone according to claim 1 or 4, characterized in that, The support protrusion is silicon nitride and / or silicon oxide.

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