MEMS microphone chip

Abstract

The present utility model provides a MEMS microphone chip, comprising: a substrate having a back cavity; a diaphragm fixed to the substrate and located above the back cavity; and a back plate arranged spaced apart from the diaphragm in a vibration direction to form an inner cavity. The diaphragm comprises: a main body portion located above the back cavity; a support portion surrounding the main body portion and fixed to the substrate; and an air release valve partially spaced apart from the main body portion to form a first air release gap, the air release valve comprising at least one air release member. The air release member comprises: a fixed portion connected to the main body portion; a movable portion arranged spaced apart from the main body portion; and a connecting portion connecting the fixed portion to the movable portion, the width of the fixed portion being less than the width of the movable portion. The MEMS microphone chip provided in the present utility model has high reliability.

Description

MEMS microphone chip Technical Field

[0001] This utility model relates to the field of electroacoustic conversion, and in particular to a MEMS microphone chip. Background Technology

[0002] MEMS microphone chips are important acoustic components in portable electronic devices, used to convert electrical signals into sound signals.

[0003] In related technologies, MEMS microphone chips are susceptible to damage from high-pressure airflow during operation, which reduces their performance and lifespan. To improve the reliability of MEMS microphone chips under high-pressure airflow, a venting structure is typically incorporated into the diaphragm. This venting structure opens under the influence of airflow, enhancing the chip's venting capability. However, the repeated opening and closing of the venting structure under pressure can lead to stress concentration at its fixing points, causing damage and further reducing the chip's reliability. Technical issues

[0004] Therefore, it is necessary to propose a new MEMS microphone chip to solve the above problems. Technical solutions

[0005] The purpose of this invention is to overcome the above-mentioned technical problems and provide a MEMS microphone chip with good reliability under high-pressure airflow.

[0006] To achieve the above objectives, this utility model proposes a MEMS microphone chip, which includes a substrate with a back cavity, a diaphragm fixed to the substrate and located above the back cavity, and a back plate that is spaced apart from the diaphragm along the vibration direction to form an inner cavity. The diaphragm includes a main body located above the back cavity, a support portion surrounding the main body and fixed to the substrate, and a vent valve that forms a first vent slit at a partial interval from the main body. The vent valve includes at least one vent plate, and the vent plate includes a fixed portion connected to the main body, a movable portion spaced apart from the main body, and a connecting portion connecting the fixed portion and the movable portion. The width of the fixed portion is smaller than the width of the movable portion.

[0007] Preferably, the backplate includes a blocking portion extending from a surface near the diaphragm toward the diaphragm, the blocking portion and the vent valve being spaced apart relative to each other along the vibration direction.

[0008] Preferably, the connecting portion is arc-shaped.

[0009] Preferably, the vent valve includes two vent plates, which are spaced apart and have a rotationally symmetrical structure.

[0010] Preferably, the connecting part includes a first connecting part connected to the fixed part, a second connecting part connected to the movable part, and a third connecting part connecting the first connecting part and the second connecting part. When the vent valve moves toward the back plate under the impact of airflow, the two second connecting parts contact each other to achieve self-locking.

[0011] Preferably, the width of the third connecting portion is smaller than the widths of the first connecting portion and the second connecting portion.

[0012] Preferably, the diaphragm includes a plurality of vent valves, which are spaced apart from each other and arranged in a ring.

[0013] Preferably, the diaphragm is further provided with a second venting slit extending through it, and the second venting slit communicates with the first venting slit.

[0014] Preferably, the strength of the venting plate is greater than the strength of the main body of the diaphragm. Beneficial effects

[0015] Compared with related technologies, the diaphragm of the MEMS microphone chip provided by this utility model includes a support portion fixed to a substrate, a main body portion located above the back cavity, and a vent valve forming a first vent slit spaced apart from the main body portion. The vent valve includes at least one vent plate, which includes a fixed portion connected to the main body portion, a movable portion spaced apart from the main body portion, and a connecting portion connecting the fixed portion and the movable portion. The width of the fixed portion is smaller than the width of the movable portion. By adopting a structure in which the fixed portion of the vent plate is narrow and the movable portion is wide, the stress concentration at the connection between the fixed portion of the vent plate and the main body portion of the diaphragm is reduced, effectively improving the reliability of the MEMS microphone chip under high-pressure airflow. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0017] Figure 1 is a perspective view of the MEMS microphone chip in this utility model.

[0018] Figure 2 is a cross-sectional view of the MEMS microphone chip in Figure 1 along line AA.

[0019] Figure 3 is a schematic diagram of the vent valve in the MEMS microphone chip of this invention under airflow.

[0020] Figure 4 is a top view of the diaphragm in one embodiment of the MEMS microphone chip of this utility model.

[0021] Figure 5 is an enlarged view of part B in Figure 4.

[0022] Figure 6 is a top view of the diaphragm in another embodiment of the MEMS microphone chip of this utility model.

[0023] Figure 7 is an enlarged view of part C in Figure 6.

[0024] Figure 8 is a top view of the diaphragm in another embodiment of the MEMS microphone chip of this utility model.

[0025] Figure 9 is an enlarged view of part D in Figure 8. The best embodiment of the present invention

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present utility model, and not all of them. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0027] As shown in Figures 1 and 2, this utility model provides a MEMS microphone chip 100, which includes a substrate 10 having a back cavity 11, a diaphragm 20 fixed to the substrate 10 and located above the back cavity 11, and a back plate 40 formed by a cavity 30 spaced apart from the diaphragm 20 along the vibration direction. Specifically, in this embodiment, the back plate 40 is located on the side of the diaphragm 20 away from the substrate 10. A first support portion 50 is also provided between the substrate 10 and the diaphragm 20 for supporting the diaphragm 20 above the back cavity 11. A second support portion 60 is provided between the diaphragm 20 and the back plate 40 for separating the diaphragm 20 and the back plate 40.

[0028] As shown in Figures 2-5, the diaphragm 20 includes a main body 21 located above the back cavity 11, a support portion 22 surrounding the main body 21 and fixed to the substrate 10, and a vent valve 24 that forms a first vent slit 23 at a partial interval from the main body 21. When the MEMS microphone chip 100 is in normal working condition, the vent valve 24 is closed. At this time, the first vent slit 23 connects the back cavity 11 to the inner cavity 30, thereby ensuring that the MEMS microphone chip 100 has good low-frequency performance. As shown in Figure 3, under the action of high-pressure airflow, the vent valve 24 opens, ensuring good venting performance.

[0029] Furthermore, the vent valve 24 includes at least one vent plate 25. The vent plate 25 includes a fixed portion 251 connected to the main body 21, a movable portion 252 spaced apart from the main body 21, and a connecting portion 253 connecting the fixed portion 251 and the movable portion 252. The width of the fixed portion 251 is smaller than the width of the movable portion 252. By adopting a structure in which the fixed portion 251 of the vent plate 25 is narrow and the movable portion 252 is wide, the stress concentration at the connection between the fixed portion 251 of the vent plate 25 and the main body 21 of the diaphragm 20 is reduced, effectively improving the reliability of the MEMS microphone chip 100 under high-pressure airflow.

[0030] Furthermore, as shown in Figures 2-5, the vent valve 24 includes two vent plates 25, which are spaced apart and have a rotationally symmetrical structure. Specifically, the connecting portion 253 includes a first connecting portion 2531 connected to the fixed portion 251, a second connecting portion 2532 connected to the movable portion 252, and a third connecting portion 2533 connecting the first connecting portion 2531 and the second connecting portion 2532. When the diaphragm 20 operates under the impact of high-pressure airflow, as the vent valve 24 moves toward the back plate 40, the second connecting portions 2532 of the two vent plates 25 contact each other to achieve self-locking, which helps to suppress the deformation of the vent plates 25 under high-pressure airflow, thereby reducing the stress concentration of the vent plates 25 and further improving the reliability of the MEMS microphone chip 100 under high-pressure airflow. Specifically, the connecting portion 253 is arc-shaped, and the width of the third connecting portion 2533 is smaller than the width of the first connecting portion 2531 and the second connecting portion 2532.

[0031] Furthermore, the backplate 40 includes a blocking portion 41 extending from the surface near the diaphragm 20 toward the diaphragm 20, the blocking portion 41 and the vent valve 24 being spaced apart relative to each other along the vibration direction. As shown in FIG3, when the vent valve 24 moves toward the backplate 40 under the action of high air pressure, it is limited by the blocking portion 41, which helps to suppress the deformation of the vent plate 25 under high air pressure, thereby reducing the stress concentration of the vent plate 25 and further improving the reliability of the MEMS microphone chip 100 under high air pressure.

[0032] Specifically, the diaphragm 20 includes a plurality of vent valves 24, which are spaced apart from each other and arranged in a ring. As shown in Figures 6 and 7, the diaphragm 20 is also provided with a second vent slit 26 that extends through it. The second vent slit 26 communicates with the first vent slit 23, further improving the venting capability of the MEMS microphone chip 100.

[0033] To further enhance the reliability of the vent valve 24 under high-pressure airflow, the strength of the vent plate 25 is greater than the strength of the main body 21 of the diaphragm 20.

[0034] To further enhance the venting capability of the MEMS microphone chip 100, a third venting slit 27 is provided on the diaphragm 20, extending along the vibration direction. The third venting slit 27 connects the back cavity 11 and the inner cavity 30. Specifically, as shown in Figures 8-9, the third venting slit 27 connects to the first venting slit 23 and is located on both sides of the venting valve 24.

[0035] Compared with related technologies, the diaphragm of the MEMS microphone chip provided by this utility model includes a support portion fixed to a substrate, a main body portion located above the back cavity, and a vent valve forming a first vent slit spaced apart from the main body portion. The vent valve includes at least one vent plate, which includes a fixed portion connected to the main body portion, a movable portion spaced apart from the main body portion, and a connecting portion connecting the fixed portion and the movable portion. The width of the fixed portion is smaller than the width of the movable portion. By adopting a structure in which the fixed portion of the vent plate is narrow and the movable portion is wide, the stress concentration at the connection between the fixed portion of the vent plate and the main body portion of the diaphragm is reduced, effectively improving the reliability of the MEMS microphone chip under high-pressure airflow.

[0036] The above description is merely an embodiment of this utility model. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of this utility model, but these improvements all fall within the protection scope of this utility model.

Claims

1. A MEMS microphone chip comprising a substrate having a back cavity, a diaphragm fixed to the substrate and located above the back cavity, and a back plate spaced apart from the diaphragm in a vibration direction to form an inner cavity, the diaphragm comprising a main body portion located above the back cavity, a support portion surrounding the main body portion and fixed to the substrate, and a vent valve partially spaced apart from the main body portion to form a first vent slit, characterized in that, The vent valve includes at least one vent plate, which includes a fixed part connected to the main body, a movable part spaced apart from the main body, and a connecting part connecting the fixed part and the movable part. The width of the fixed part is smaller than the width of the movable part.

2. The MEMS microphone chip of claim 1, wherein, The backplate includes a blocking portion extending from the surface near the diaphragm toward the diaphragm, and the blocking portion and the vent valve are spaced apart from each other along the vibration direction.

3. The MEMS microphone chip of claim 1, wherein, The connecting part is arc-shaped.

4. The MEMS microphone chip of claim 3, wherein, The vent valve includes two vent plates, which are spaced apart and have a rotationally symmetrical structure.

5. The MEMS microphone chip of claim 4, wherein, The connecting part includes a first connecting part connected to the fixed part, a second connecting part connected to the movable part, and a third connecting part connecting the first connecting part and the second connecting part. When the vent valve moves toward the back plate under the impact of airflow, the two second connecting parts contact each other to achieve self-locking.

6. The MEMS microphone chip of claim 5, wherein, The width of the third connecting part is smaller than the width of the first connecting part and the second connecting part.

7. The MEMS microphone chip of claim 1, wherein, The diaphragm includes a plurality of vent valves, which are spaced apart from each other and arranged in a ring.

8. The MEMS microphone chip of claim 1, wherein, The diaphragm is also provided with a second venting slit that runs through it, and the second venting slit is connected to the first venting slit.

9. The MEMS microphone chip of claim 1, wherein, The strength of the venting plate is greater than the strength of the main body of the diaphragm.

Images