MEMS microphone chip

Abstract

The MEMS microphone chip provided by the utility model comprises a substrate with a back cavity, a vibrating diaphragm which is fixed on the substrate and is positioned above the back cavity, and a back plate which is arranged at an interval with the vibrating diaphragm along the vibration direction to form an inner cavity, the vibrating diaphragm comprises a main body part located above the back cavity, a supporting part surrounding the main body part and fixed on the substrate, and an air release valve partially spaced from the main body part to form a first air release gap, and the air release valve comprises at least one air release sheet; the fixed part is connected with the main body part, the movable part and the main body part are arranged at an interval, the connecting part is connected with the fixed part and the movable part, and the width of the fixed part is smaller than that of the movable part. The MEMS microphone chip provided by the utility model is high in reliability.

Description

Technical field

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

[0002] MEMS microphone chips are important acoustic components in portable electronic devices, used to complete the conversion between electrical signals and sound signals.

[0003] In related technologies, MEMS microphone chips are susceptible to damage during operation due to the impact of high-pressure airflow, reducing their performance and service life. To improve the reliability of MEMS microphone chips under high-pressure airflow, a vent structure is typically installed on the diaphragm. This vent structure opens in response to the pressure flow, enhancing the MEMS microphone chip's airflow capacity. However, the repeated opening and closing of the vent structure under pressure can easily cause stress concentration at the vent structure's fixing points, leading to damage and reducing the reliability of the MEMS microphone chip.

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

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

[0006] In order to achieve the above-mentioned purpose, the present invention proposes a MEMS microphone chip, which includes 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 along the vibration direction to form an inner cavity, the diaphragm includes a main body located above the back cavity, a supporting part surrounding the main body and fixed to the substrate, and a relief valve spaced apart from the main body to form a first relief gap, the relief valve includes at least one relief piece, the relief piece 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, and the width of the fixed part is smaller than the width of the movable part.

[0007] Preferably, the back plate includes a blocking portion extending from a surface close to the diaphragm toward the diaphragm, and the blocking portion and the air release valve are arranged relative to each other and spaced apart along the vibration direction.

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

[0009] Preferably, the air relief valve includes two air relief 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 air release 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 the air relief valves, and the plurality of the air relief valves are spaced apart from each other and arranged in a ring shape.

[0013] Preferably, the diaphragm is further provided with a second air relief slit running through the diaphragm, and the second air relief slit is connected to the first air relief slit.

[0014] Preferably, the strength of the air release sheet is greater than the strength of the main body of the diaphragm.

[0015] Compared to related technologies, the diaphragm of the MEMS microphone chip provided by this utility model comprises a support portion fixed to a substrate, a main body portion located above a back cavity, and a bleed valve spaced apart from the main body portion to form a first bleed gap. The bleed valve comprises at least one bleed 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 fixed portion is narrower than the movable portion. The narrow fixed portion and wide movable portion of the bleed plate reduce stress concentration at the connection between the fixed portion and the main body portion of the diaphragm, effectively improving the reliability of the MEMS microphone chip under high-pressure airflow.

Brief Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. Among them:

[0017] Figure 1 It is a three-dimensional diagram of the MEMS microphone chip in the present invention.

[0018] Figure 2 yes Figure 1 Cross-sectional view of the MEMS microphone chip along line AA.

[0019] Figure 3 This is a schematic diagram of the air release valve in the MEMS microphone chip of the present invention under air flow.

[0020] Figure 4 This is a top view of the diaphragm in one embodiment of the MEMS microphone chip of the present invention.

[0021] Figure 5 yes Figure 4 Magnified view of part B.

[0022] Figure 6 FIG. 1 is a top view of a diaphragm in another embodiment of the MEMS microphone chip of the present invention.

[0023] Figure 7 yes Figure 6 Magnified view of part C.

[0024] Figure 8 FIG. 1 is a top view of a diaphragm in another embodiment of the MEMS microphone chip of the present invention.

[0025] Figure 9 yes Figure 8 Magnified view of part D. [Specific implementation method]

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field of the present invention without making creative efforts are within the scope of protection of the present invention.

[0027] like Figure 1-Figure 2 As shown, the present invention 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 spaced apart from the diaphragm 20 along the vibration direction to form an inner cavity 30. 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 further 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 spacing the diaphragm 20 and the back plate 40 apart.

[0028] like Figure 2-Figure 5As shown, 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 bleed valve 24 partially separated from the main body 21 to form a first bleed gap 23. When the MEMS microphone chip 100 is in normal working condition, the bleed valve 24 is closed. At this time, the first bleed gap 23 connects the back cavity 11 with the inner cavity 30, thereby ensuring that the MEMS microphone chip 100 has good low-frequency performance. Figure 3 As shown, under the action of high-pressure airflow, the air release valve 24 opens, ensuring good air release performance.

[0029] Furthermore, the bleed valve 24 includes at least one bleed piece 25, which 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 fixed portion 251 is narrower than the movable portion 252. The narrow fixed portion 251 and wide movable portion 252 structure of the bleed piece 25 reduces stress concentration at the connection between the fixed portion 251 of the bleed piece 25 and the main body 21 of the diaphragm 20, effectively improving the reliability of the MEMS microphone chip 100 under high-pressure airflow.

[0030] In addition, if Figure 2-Figure 5 As shown, the bleed valve 24 includes two bleed sheets 25 spaced apart and forming 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 and the bleed valve 24 moves toward the backplate 40, the second connecting portions 2532 of the two bleed sheets 25 contact each other to achieve self-locking. This helps suppress deformation of the bleed sheets 25 under high-pressure airflow, thereby reducing stress concentration on the bleed sheets 25 and further improving the reliability of the MEMS microphone chip 100 under high-pressure airflow. Specifically, the connecting portion 253 is curved, and the width of the third connecting portion 2533 is smaller than the widths of the first connecting portion 2531 and the second connecting portion 2532.

[0031] Furthermore, the back plate 40 includes a blocking portion 41 extending from a surface close to the diaphragm 20 toward the diaphragm 20, and the blocking portion 41 and the air release valve 24 are arranged relative to each other along the vibration direction. Figure 3As shown, when the air release valve 24 moves toward the back plate 40 under the action of high air pressure, it will be limited by the blocking portion 41, which is beneficial to suppress the deformation of the air release sheet 25 under high-pressure air flow, thereby reducing the stress concentration of the air release sheet 25 and further improving the reliability of the MEMS microphone chip 100 under high-pressure air flow.

[0032] Specifically, the diaphragm 20 includes a plurality of the air release valves 24, which are spaced apart from each other and arranged in a ring shape. Figure 6-Figure 7 As shown, the diaphragm 20 is further provided with a second air relief slit 26 running through the diaphragm 20 . The second air relief slit 26 is communicated with the first air relief slit 23 , further improving the air relief capability of the MEMS microphone chip 100 .

[0033] In order to further enhance the reliability of the air release valve 24 under high-pressure airflow, the strength of the air release sheet 25 is greater than the strength of the main body 21 of the diaphragm 20 .

[0034] In order to further enhance the air release capability of the MEMS microphone chip 100, the diaphragm 20 is further provided with a third air release slit 27 penetrating the diaphragm along the vibration direction. The third air release slit 27 connects the back cavity 11 and the inner cavity 30. Specifically, Figure 8-Figure 9 As shown, the third air relief slit 27 is communicated with the first air relief slit 23 and is provided on both sides of the air relief valve 24 .

[0035] Compared to related technologies, the diaphragm of the MEMS microphone chip provided by this utility model comprises a support portion fixed to a substrate, a main body portion located above a back cavity, and a bleed valve spaced apart from the main body portion to form a first bleed gap. The bleed valve comprises at least one bleed 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 fixed portion is narrower than the movable portion. The narrow fixed portion and wide movable portion of the bleed plate reduce stress concentration at the connection between the fixed portion and the main body portion of the diaphragm, effectively improving the reliability of the MEMS microphone chip under high-pressure airflow.

[0036] The above is only an embodiment of the present invention. It should be pointed out that those skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements are all within the scope of protection of the present invention.

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 along the vibration direction to form an inner cavity, the diaphragm comprising a main body located above the back cavity, a support portion surrounding the main body and fixed to the substrate, and a bleed valve partially spaced apart from the main body to form a first bleed gap, characterized in that: The air release valve includes at least one air release sheet, which 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, wherein the width of the fixed portion is smaller than that of the movable portion.

2. The MEMS microphone chip according to claim 1, characterized in that: The back plate includes a blocking portion extending from a surface close to the diaphragm toward the diaphragm, and the blocking portion and the air release valve are arranged relative to each other and spaced apart along the vibration direction.

3. The MEMS microphone chip according to claim 1, wherein: The connecting portion is arc-shaped.

4. The MEMS microphone chip according to claim 3, characterized in that: The air release valve includes two air release plates, which are spaced apart and have a rotationally symmetrical structure.

5. The MEMS microphone chip according to claim 4, characterized in that: 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 air release 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 according to claim 5, characterized in that: The third connection portion has a width smaller than that of the first connection portion and the second connection portion.

7. The MEMS microphone chip according to claim 1, characterized in that: The diaphragm includes a plurality of the air release valves, which are spaced apart from each other and arranged in a ring shape.

8. The MEMS microphone chip according to claim 1, wherein: The diaphragm is further provided with a second air relief slit running through the diaphragm, and the second air relief slit is communicated with the first air relief slit.

9. The MEMS microphone chip according to claim 1, wherein: The strength of the air release sheet is greater than the strength of the main body of the diaphragm.

Images