CN215818620U

CN215818620U - MEMS microphone

Info

Publication number: CN215818620U
Application number: CN202122199135.3U
Authority: CN
Inventors: 石正雨; 王凯杰; 张睿
Original assignee: AAC Acoustic Technologies Shenzhen Co Ltd
Current assignee: AAC Technologies Holdings Shenzhen Co Ltd
Priority date: 2021-09-10
Filing date: 2021-09-10
Publication date: 2022-02-11
Anticipated expiration: 2031-09-10

Abstract

The utility model provides an MEMS microphone, which comprises a substrate with a cavity and a capacitor structure arranged on the substrate, wherein the capacitor structure comprises a back plate and a vibrating diaphragm arranged opposite to the back plate, the vibrating diaphragm comprises a first part opposite to the cavity, a second part positioned on the outer side and a spring structure connecting the first part and the second part, the spring structure is formed into a circle along the circumferential direction of the vibrating diaphragm, the vibrating diaphragm is closer to the substrate than the back plate, and a first protruding part extending towards the vibrating diaphragm is arranged on the surface of the back plate facing the vibrating diaphragm. Compared with the prior art, the two parts of the vibrating diaphragm of the MEMS microphone are connected through the spring, so that the stress is effectively released while the vibrating diaphragm is connected, the reliability of the MEMS microphone is enhanced, and the sensitivity and the low-frequency performance of the MEMS microphone are improved.

Description

MEMS microphone

[ technical field ] A method for producing a semiconductor device

The utility model relates to the field of sensors, in particular to an MEMS microphone.

[ background of the utility model ]

MEMS microphone chips are more and more widely applied, and the reliability requirement on the chips is higher and higher. Taking a capacitive MEMS microphone chip as an example, the chip includes a substrate having a back cavity, and a diaphragm and a backplate structure located on the upper portion of the substrate, wherein the diaphragm and the backplate structure form a capacitive system. External sound pressure causes the diaphragm to move through the through-hole of the backplate structure, which will change the distance between the diaphragm and the backplate structure, thereby changing the capacitance and ultimately converting into an electrical signal.

However, in the prior art, the microphone back plate and the diaphragm are separated by the sacrificial layer, the back plate is fixed all around, the diaphragm is fixed on the periphery or fixed partially, when the periphery of the diaphragm is fixed completely, the internal stress of the diaphragm causes the diaphragm to be tensioned, the rigidity of the diaphragm is increased, the sensitivity of the microphone is reduced, and when the periphery of the diaphragm is fixed partially, an air release groove is formed, so that the low-frequency performance of the microphone is reduced.

Therefore, there is a need to provide a new MEMS microphone to solve the above technical problems.

[ Utility model ] content

The utility model aims to provide an MEMS microphone with high reliability and high sensitivity.

In order to achieve the above object, the present invention provides an MEMS microphone, which includes a substrate having a cavity and a capacitor structure disposed on the substrate, wherein the capacitor structure includes a backplate and a diaphragm disposed opposite to the backplate, and the MEMS microphone is characterized in that the diaphragm includes a first portion opposite to the cavity, a second portion located outside the first portion, and a spring structure connecting the first portion and the second portion, and the spring structure is formed in a circle along a circumferential direction of the diaphragm.

Preferably, the first protrusion is spaced apart from the diaphragm.

Preferably, the back plate includes a middle portion and a peripheral side portion connected to the middle portion, and the first protruding portion is disposed on the peripheral side portion.

Preferably, the first protruding portion is a protruding structure continuously arranged in the circumferential direction, or a plurality of protruding structures arranged at intervals.

Preferably, the middle part of the back plate is provided with a first fixing column which extends towards the vibrating diaphragm and is connected with the vibrating diaphragm.

Preferably, a first supporting portion connected with the substrate is arranged at the peripheral side portion of the back plate, the back plate is fixed with the substrate only through the first supporting portion, a second supporting portion is arranged at the second portion of the vibrating diaphragm, and the vibrating diaphragm is fixed with the substrate only through the second supporting portion.

Preferably, the MEMS microphone includes a substrate having a cavity, and a capacitor structure disposed on the substrate, where the capacitor structure includes a backplate and a diaphragm disposed opposite to the backplate, and is characterized in that the diaphragm includes a first portion opposite to the cavity, a second portion located outside, and a spring structure connecting the first portion and the second portion, the spring structure is formed into a circle along a circumferential direction of the diaphragm, the backplate is closer to the substrate than the diaphragm, a second protruding portion extending toward the backplate is disposed on a surface of the diaphragm facing the backplate, and the second protruding portion is located on the second portion of the diaphragm and spaced from the backplate.

Preferably, the first part of the diaphragm is provided with a second fixing column which extends towards the back plate and is connected with the back plate.

Preferably, the back plate is provided with a first supporting portion connected with the substrate, the back plate is fixed with the substrate only through the first supporting portion, the second portion of the vibrating diaphragm is provided with a second supporting portion, and the vibrating diaphragm is fixed with the back plate only through the second supporting portion.

Preferably, the second protruding portion is a protruding structure continuously arranged in the circumferential direction, or a plurality of protruding structures arranged at intervals.

Compared with the prior art, the two parts of the MEMS microphone diaphragm are connected through the spring structure, when the diaphragm has internal stress, the diaphragm can release the stress through deformation, so that the influence of the stress on the rigidity of the diaphragm is reduced, the sensitivity of the MEMS microphone is improved, and the low-frequency performance of the MEMS microphone is improved because the position of the peripheral protruding part surrounds the periphery of the whole diaphragm.

[ description of the drawings ]

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without inventive efforts, wherein:

FIG. 1 is a perspective view of a MEMS microphone of the present invention;

FIG. 2 is a partially exploded view of a MEMS microphone of the present invention;

FIG. 3 is a perspective view of a diaphragm of the MEMS microphone of the present invention;

FIG. 4 is a cross-sectional view taken along line A-A of FIG. 1;

fig. 5 is a cross-sectional view of a MEMS microphone according to another embodiment of the utility model.

[ detailed description ] embodiments

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-4, an MEMS microphone 100 according to the present invention includes a substrate 1 having a cavity 10 and a capacitor structure 2 disposed on the substrate, where the capacitor structure 2 includes a backplate 21 and a diaphragm 22 disposed opposite to the backplate 21.

In this embodiment, the diaphragm 22 is closer to the substrate 1 than the back plate 21, the back plate 21 includes an intermediate portion 211 and a peripheral portion 212 connected to the intermediate portion 211, a first protrusion 213 extending toward the diaphragm 22 is disposed on a surface of the back plate 21 facing the diaphragm 22, the first protrusion 213 is located on the peripheral portion 212 of the back plate, and the first protrusion 213 is disposed at an interval from the diaphragm 22, that is, the first protrusion 213 extends without abutting against the diaphragm 22. The first protruding portion 213 is a protrusion structure continuously arranged in the circumferential direction, or a plurality of protrusion structures arranged at equal intervals. The first protrusion 213 provides a smaller initial gap between the diaphragm 22 and the backplate 21, and the diaphragm and the backplate have a larger initial gap except for the position of the first protrusion 213, so that the diaphragm 22 and the backplate 21 contact each other at the position of the first protrusion 213 under the action of electrostatic force to support the diaphragm 22. The first protrusion 213 is disposed around the entire circumference of the diaphragm at a position so that the low-frequency performance of the MEMS microphone becomes good.

The middle portion 211 of the back plate 21 is provided with a first fixing post 214 extending toward the diaphragm 22 and connected to the diaphragm 22. Of course, the first fixing posts 214 may be spaced apart from the diaphragm 22, and a small gap exists between the first fixing posts and the diaphragm, so that the diaphragm is connected to the backplate under the action of electrostatic force. The peripheral side portion 212 of the backplate is provided with a first support portion 215 connected to the base 1, and the backplate 21 is fixed to the base 1 only by the first support portion 215.

The diaphragm 22 may be circular or polygonal in shape, the diaphragm 22 includes a first portion 221 opposite to the cavity 10, a second portion 222 located outside, and a spring structure 223 connecting the first portion 221 and the second portion 222, the spring structure 223 is formed in a circle along the circumferential direction of the diaphragm 22, and since the spring structure 223 has a smaller stiffness, when the diaphragm 22 has internal stress, the diaphragm 22 may release the stress through easier deformation, so that the influence of the stress on the stiffness of the diaphragm 22 is reduced, and the sensitivity of the MEMS microphone is improved.

The second portion 222 of the diaphragm 22 is provided with a second supporting portion 224, the diaphragm 22 is fixed to the substrate 1 only through the second supporting portion 224, and the second supporting portion 224 and the diaphragm 22 may be an integral structure or a split structure. No sacrificial layer is left between the diaphragm 22 and the backplate 21.

In another embodiment of the present invention, as shown in fig. 5, the back plate 21 is closer to the substrate 1 than the diaphragm 22, the back plate 21 is provided with a first supporting portion 215 connected to the substrate 1, the back plate 21 is fixed to the substrate 1 only through the first supporting portion 215, and the first supporting portion 215 and the back plate 21 may be a split structure or an integrated structure.

The surface of the diaphragm 22 facing the back plate 21 is provided with a second protrusion 223 extending towards the back plate 21, and the second protrusion 223 is located on the second portion 222 of the diaphragm 22 and spaced apart from the back plate 21. The second protruding portion 223 is a protruding structure continuously arranged along the circumferential direction, or a plurality of protruding structures arranged at intervals. The first portion 221 of the diaphragm 22 is provided with a second fixing post 225 extending toward the back plate 21 and connected to the back plate 21. Of course, the second fixing posts 225 may also be spaced from the backplate 21, and there is a small gap between them, so that the diaphragm is connected with the backplate under the action of electrostatic force.

The second portion 222 of the diaphragm 22 is provided with a second supporting portion 224, and the diaphragm 22 is fixed with the back plate 21 only through the second supporting portion 224. No sacrificial layer is left between the diaphragm 22 and the backplate 21.

While the foregoing is directed to embodiments of the present invention, it will be understood by those skilled in the art that various changes may be made without departing from the spirit and scope of the utility model.

Claims

1. The MEMS microphone is characterized in that the vibrating diaphragm comprises a first part opposite to the cavity, a second part located on the outer side and a spring structure connecting the first part and the second part, the spring structure is formed into a circle along the circumferential direction of the vibrating diaphragm, the vibrating diaphragm is closer to the substrate than the back plate, and a first protruding portion extending towards the vibrating diaphragm is arranged on the surface of the back plate facing the vibrating diaphragm.

2. The MEMS microphone of claim 1, wherein the first protrusion is spaced apart from the diaphragm.

3. The MEMS microphone of claim 2, wherein the back plate comprises a middle portion and a peripheral side portion connected to the middle portion, the first protrusion being disposed on the peripheral side portion.

4. The MEMS microphone of claim 3, wherein the first protruding portion is a protruding structure that is continuously provided in a circumferential direction, or a plurality of protruding structures that are provided at intervals.

5. The MEMS microphone of claim 3, wherein the middle portion of the back plate is provided with a first fixing post extending toward and connected to the diaphragm.

6. The MEMS microphone of claim 3, wherein the peripheral side portion of the back plate is provided with a first support portion connected to the substrate, the back plate is fixed to the substrate only by the first support portion, and the second portion of the diaphragm is provided with a second support portion, the diaphragm is fixed to the substrate only by the second support portion.

7. An MEMS microphone comprises a substrate with a cavity and a capacitor structure arranged on the substrate, wherein the capacitor structure comprises a back plate and a vibrating diaphragm arranged opposite to the back plate, and is characterized in that the vibrating diaphragm comprises a first part opposite to the cavity, a second part located on the outer side and a spring structure connecting the first part and the second part, the spring structure is formed into a circle along the circumferential direction of the vibrating diaphragm, the back plate is closer to the substrate than the vibrating diaphragm, a second protruding part extending towards the back plate is arranged on the surface of the vibrating diaphragm facing the back plate, and the second protruding part is located on the second part of the vibrating diaphragm and is arranged at an interval with the back plate.

8. The MEMS microphone of claim 7, wherein the first portion of the diaphragm is provided with a second fixing post extending toward and connected to the backplate.

9. The MEMS microphone of claim 7, wherein the backplate is provided with a first support portion connected to the substrate, the backplate being fixed to the substrate only by the first support portion, the second portion of the diaphragm being provided with a second support portion, the diaphragm being fixed to the backplate only by the second support portion.

10. The MEMS microphone of claim 7, wherein the second protruding portion is a protruding structure that is continuously provided in a circumferential direction, or a plurality of protruding structures that are provided at intervals.