MEMS microphone chip

Abstract

The microphone chip provided in the present utility model comprises a substrate having a back cavity and a capacitor system fixed on the substrate and disposed above the back cavity, wherein the capacitor system comprises a diaphragm and a back plate which are disposed opposite each other and spaced apart from each other, the diaphragm comprises a vibrating part and several elastic connecting parts disposed at the edge of the vibrating part, and the diaphragm is fixed to the substrate by means of the elastic connecting parts; and the vibrating part comprises a middle vibrating part located in the middle position and an outer vibrating part connected to the middle vibrating part and the elastic connecting parts, an anchoring part extending towards the diaphragm is disposed on the back plate, and the anchoring part is fixedly connected to the middle vibrating part. The MEMS microphone chip provided in the present utility model is highly reliability.

Description

MEMS microphone chip TECHNICAL FIELD

[0001] The utility model relates to electroacoustic conversion technical field especially relates to a microphone chip for portable mobile terminal. BACKGROUND

[0002] MEMS microphone chip is widely used in acoustic device, such as common MEMS condenser microphone structure. The MEMS microphone chip in the related art includes a substrate with a back cavity, and a back plate and a diaphragm arranged on the substrate and spaced apart from each other. When the sound pressure acts on the diaphragm, the diaphragm has a pressure difference between the two surfaces facing the back plate and away from the back plate, causing the diaphragm to move towards or away from the back plate, thereby causing the change of the capacitance between the diaphragm and the back plate, realizing the conversion of sound signal to electric signal. TECHNICAL PROBLEM

[0003] In the related art, the diaphragm and the back plate in the MEMS microphone chip are completely spaced apart, and the diaphragm is generally fixed on the substrate in a full-week fixed manner, which makes the movement amplitude of the diaphragm too large during drop test, reducing the reliability of the MEMS microphone chip.

[0004] Therefore, it is necessary to provide a new microphone chip to solve the above technical problems. TECHNICAL SOLUTION

[0005] The utility model discloses a MEMS microphone chip with high reliability.

[0006] In order to achieve the above purpose, the utility model provides a MEMS microphone chip, which comprises a substrate with a back cavity and a capacitor system fixed on the substrate and arranged above the back cavity, the capacitor system comprising a diaphragm and a back plate spaced apart from each other, the diaphragm comprising a vibration part and a plurality of elastic connecting parts arranged at the edge of the vibration part, the diaphragm being fixed to the substrate through the elastic connecting parts; the vibration part comprises a middle vibration part at the middle position and an outer vibration part connecting the middle vibration part and the elastic connecting part, the back plate is provided with an anchoring part extending towards the diaphragm, and the anchoring part is fixedly connected with the middle vibration part.

[0007] Preferably, the back plate comprises an insulating layer and an electrode layer arranged on the side of the insulating layer facing the diaphragm, the electrode layer comprising an electrode part generating an electric signal in opposite motion with the diaphragm and a partition part electrically isolated from the electrode part, and the anchoring part extends from the partition part to form the diaphragm.

[0008] Preferably, the back plate comprises an insulating layer and an electrode layer arranged on the side of the insulating layer facing the diaphragm, the anchoring part is formed in the insulating layer.

[0009] Preferably, the insulating layer comprises an anchoring area not arranged opposite to the electrode layer along the vibration direction, the anchoring area is recessed towards the diaphragm to form the anchoring portion fixed with the diaphragm.

[0010] Preferably, the insulating layer comprises an anchoring area not arranged opposite to the electrode layer along the vibration direction, the anchoring portion extends from the anchoring area to pass through the electrode layer and is fixed with the diaphragm.

[0011] Preferably, a plurality of elastic connecting portions are arranged at the edge of the outer vibration portion in a ring shape, the elastic connecting portion comprises a first connecting portion connected with the edge of the outer vibration portion, a second connecting portion connected with the substrate, and an elastic portion connecting the first connecting portion and the second connecting portion, the elastic portion comprises a plurality of bending portions connected with each other, and the bending portions are in S shape.

[0012] Preferably, the second connecting portion is connected with two bending portions, the vibration portion of the diaphragm is in circular shape, the second connecting portion comprises a radial central axis, and the two bending portions are in axisymmetric structure relative to the central axis.

[0013] Preferably, the first connecting portion is arranged at one end of the bending portion away from the second connecting portion. Beneficial effects

[0014] Compared with the related art, the diaphragm of the MEMS microphone chip comprises a vibration portion and a plurality of elastic connecting portions arranged at the edge of the vibration portion, the diaphragm is fixed to the substrate through the elastic connecting portions; the vibration portion comprises a middle vibration portion at a middle position and an outer vibration portion connecting the middle vibration portion and the elastic connecting portion, the back plate is provided with an anchoring portion extending towards the diaphragm, and the anchoring portion is fixedly connected with the middle vibration portion; the diaphragm is anchored on the substrate through the plurality of elastic connecting portions, and the middle region of the diaphragm is anchored with the back plate, so that the reliability of the MEMS microphone chip is effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor, wherein:

[0016] Fig. 1 is a perspective view of the microphone chip in the present application;

[0017] Fig. 2 is an exploded view of the microphone chip in the present application;

[0018] Fig. 3 is a sectional view along line A-A in Fig. 1.

[0019] Fig. 4 is a top view of a diaphragm and a second support portion in a microphone chip according to the present application;

[0020] Fig. 5 is a schematic view of one embodiment of the cross-sectional view in Fig. 3;

[0021] Fig. 6 is a schematic view of another embodiment of the cross-sectional view in Fig. 3. Best Mode for Carrying Out the Invention

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application.

[0023] As shown in Figs. 1-4, the present application provides a MEMS microphone chip 100, which comprises a substrate 20 having a back cavity 10 and a capacitor system 30 fixed on the substrate 20 and arranged above the back cavity 10; the capacitor system 30 comprises a diaphragm 31 and a back plate 32 arranged opposite to each other, under the action of sound pressure, the diaphragm 31 vibrates to change the distance between the diaphragm 31 and the back plate 32, thereby causing the capacitance to change, so as to detect the sound signal. In the present embodiment, the back plate 32 is located on the side of the diaphragm 31 away from the substrate 20.

[0024] The diaphragm 31 comprises a vibration portion 311 and a plurality of elastic connecting portions 312 arranged at the edges of the vibration portion 311, and the diaphragm 31 is fixed to the substrate 20 through the elastic connecting portions 312.

[0025] The vibration portion 311 comprises a middle vibration portion 3111 located at a middle position and an outer vibration portion 3112 connecting the middle vibration portion 3111 and the elastic connecting portion 312; the back plate 32 is provided with an anchoring portion 321 extending towards the diaphragm 31, and the anchoring portion 321 is fixedly connected with the middle vibration portion 3111. By arranging the anchoring portion, the middle vibration region of the diaphragm is anchored with the back plate, which can effectively prevent the diaphragm from moving too much in the reliability test, thereby improving the reliability of the diaphragm.

[0026] Specifically, as shown in Figs. 1-3 and 6, the back plate 32 comprises an insulating layer 322 and an electrode layer 323 arranged on the side of the insulating layer 322 facing the diaphragm 31, the electrode layer 323 comprises an electrode portion 3231 generating an electric signal in opposite motion with the diaphragm 31 and a partition portion 3232 electrically isolated from the electrode portion 3231, and the anchoring portion 321 extends from the partition portion 3232 towards the diaphragm 31.

[0027] In other embodiments, as shown in FIGS. 1-3 and 5, the anchoring portion 321 can also be formed in the insulating layer 322. Specifically, the insulating layer 322 includes an anchoring area 3221 which is not directly opposite to the electrode layer 323 along the vibration direction, and the anchoring area 3221 is recessed towards the diaphragm 31 to form the anchoring portion 321 fixed with the diaphragm 31. That is, the anchoring portion 321 is the anchoring area 3221 at this time. Optionally, the anchoring portion 321 extends from the anchoring area 3221 to pass through the electrode layer 323 and is fixed with the diaphragm 31.

[0028] As shown in FIG. 4, a plurality of the elastic connecting portions 312 are arranged in a ring at the edge of the outer vibration portion 3112, the elastic connecting portion 312 includes a first connecting portion 3121 connected with the edge of the outer vibration portion 3112, a second connecting portion 3122 connected with the base 20, and an elastic portion 3123 connecting the first connecting portion 3121 and the second connecting portion 3122, the elastic portion 3123 includes a plurality of bending portions 3124 connected with each other, and the bending portion 3124 is in an S shape. Specifically, the second connecting portion 3122 is connected with two bending portions 3124, the vibration portion 311 of the diaphragm 31 is circular, the second connecting portion 3122 includes a radial central axis X, and the two bending portions 3124 are axially symmetric structures relative to the central axis X; the first connecting portion 3121 is arranged at one end of the bending portion 3124 away from the second connecting portion 3122.

[0029] The microphone chip 100 further includes a support portion 40 fixed on the base 20, one end of the elastic connecting portion 312 is fixed on the outer vibration portion 3112, and the other end is fixed on the support portion 40. Specifically, the support portion 40 includes a first support portion 41 fixed on the base 20 and a second support portion 42 fixed on the first support portion 41, the first support portion 41 is used to fix the back plate 32, and the second support portion 42 is used to fix the diaphragm 31.

[0030] Further, the back plate 32 is also provided with a plurality of sound holes 324 penetrating therethrough along the vibration direction, and the anchoring portion 321 is arranged on the area of the back plate 32 which is not provided with the sound hole 324.

[0031] Compared with the related art, the diaphragm of the MEMS microphone chip comprises a vibrating part and a plurality of elastic connecting parts arranged at the edge of the vibrating part, and the diaphragm is fixed to the substrate through the elastic connecting parts; the vibrating part comprises a middle vibrating part at the middle position and an outer vibrating part connecting the middle vibrating part and the elastic connecting parts, and the back plate is provided with an anchoring part extending towards the diaphragm, and the anchoring part is fixedly connected with the middle vibrating part; by anchoring the diaphragm on the substrate through the plurality of elastic connecting parts and anchoring the middle region of the diaphragm with the back plate, the reliability of the MEMS microphone chip is effectively improved.

[0032] The above only describes the embodiments of the present application, and it should be pointed out that, for those skilled in the art, improvements can be made without departing from the inventive concept of the present application, but these all belong to the protection scope of the present application.

Claims

1. A MEMS microphone chip comprising a substrate having a back cavity and a capacitive system fixed to the substrate and disposed above the back cavity, the capacitive system comprising a diaphragm and a backplate disposed in opposing spaced relation, characterized by, The diaphragm comprises a vibrating part and a plurality of elastic connecting parts arranged at the edge of the vibrating part, the diaphragm is fixed to the substrate through the elastic connecting parts; the vibrating part comprises a middle vibrating part at the middle position and an outer vibrating part connecting the middle vibrating part and the elastic connecting parts, the back plate is provided with an anchoring part extending towards the diaphragm, and the anchoring part is fixedly connected with the middle vibrating part.

2. The MEMS microphone chip of claim 1, wherein, The back plate comprises an insulating layer and an electrode layer arranged on the side of the insulating layer facing the diaphragm, the electrode layer comprises an electrode part generating an electric signal in opposite motion with the diaphragm and a partition part electrically isolated from the electrode part, and the anchoring part extends from the partition part towards the diaphragm.

3. The MEMS microphone chip of claim 1, wherein, The back plate comprises an insulating layer and an electrode layer arranged on the side of the insulating layer facing the diaphragm, and the anchoring part is formed on the insulating layer.

4. The MEMS microphone chip of claim 3, wherein, The insulating layer comprises an anchoring area not arranged opposite to the electrode layer along the vibration direction, and the anchoring area is recessed towards the diaphragm to form the anchoring part fixed with the diaphragm.

5. The MEMS microphone chip of claim 3, wherein, The insulating layer comprises an anchoring area not arranged opposite to the electrode layer along the vibration direction, and the anchoring part extends from the anchoring area to be fixed with the diaphragm through the electrode layer.

6. The MEMS microphone chip of claim 1, wherein, A plurality of elastic connecting parts are arranged in a ring at the edge of the outer vibrating part, the elastic connecting part comprises a first connecting part connected with the edge of the outer vibrating part, a second connecting part connected with the substrate, and an elastic part connecting the first connecting part and the second connecting part, the elastic part comprises a plurality of connected bending parts, and the bending part is in S shape.

7. The MEMS microphone chip of claim 6, wherein, The second connecting part is connected with two bending parts, the vibrating part of the diaphragm is circular, the second connecting part comprises a central axis along the radial direction, and the two bending parts are in axial symmetric structure relative to the central axis.

8. The MEMS microphone chip of claim 7, wherein, The first connecting part is arranged at one end of the bending part away from the second connecting part.

9. The MEMS microphone chip of claim 1, wherein, The microphone chip further comprises a support part fixed on the substrate, one end of the elastic connecting part is fixed on the outer vibrating part, and the other end is fixed on the support part.

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