WO2018040259A1

WO2018040259A1 - Sensitive membrane and mems microphone

Info

Publication number: WO2018040259A1
Application number: PCT/CN2016/103102
Authority: WO
Inventors: 詹竣凯; 蔡孟锦
Original assignee: 歌尔股份有限公司
Priority date: 2016-08-31
Filing date: 2016-10-24
Publication date: 2018-03-08
Also published as: CN206164826U

Abstract

The present invention discloses a sensitive membrane and an MEMS microphone, comprising a sensing portion located at a middle part, a connecting portion located at an edge and a motion portion located between the sensing portion and the connecting portion, the sensing portion, the motion portion and the connecting portion being formed integrally, wherein the motion portion is of a corrugated shape or of a rectangular tooth shape; and a first reinforcing portion is also provided at the position of the connecting portion. The sensitive membrane of the present invention integrates the advantages of a traditional spring-type diaphragm and a full diaphragm type structured membrane, and, by setting the form that central region type whole plane sensing can be provided in a middle region, compared with the deformation of a traditional curved surface in the same displacement range, can provide a bigger capacitance variation, thereby improving the overall sensitivity; can provide a bigger displacement for the sensing part via the motion portion with a corrugated shape or a rectangular tooth shape, thereby improving the sensitivity of the sensing portion; and can greatly improve the connecting strength of the sensitive membrane by setting the first reinforcing portion at the position of the connecting portion, thereby improving the shock resistance of the sensitive membrane.

Description

A sensitive film and MEMS microphone

Technical field

The present invention relates to a sensitive film for measurement, such as a diaphragm in a microphone or other sensitive film of a piezoresistive, piezoelectric, optical sensor; the invention also relates to a MEMS microphone.

Background technique

MEMS (Micro Electro Mechanical System) microphone is a microphone based on MEMS technology. The diaphragm and back plate are important components in MEMS microphone. The diaphragm and back plate form capacitors and are integrated on the silicon chip to realize acoustic electricity. Conversion.

The traditional diaphragm is made by forming an oxide layer on a silicon substrate, and then depositing a layer of a diaphragm on the oxide layer. After doping and tempering, the desired pattern is etched, and the diaphragm is etched. It is fixed to the substrate by rivet points at its edges. Of course, it is also necessary to extract the electrode from the diaphragm, and change the distance between the diaphragm and the back plate by the vibration of the diaphragm, thereby converting the sound signal into an electrical signal.

In the existing microphone structure, in order to improve the drop resistance of the microphone, the diaphragm is usually made thicker, but the thicker diaphragm has a problem of low sensitivity; if the diaphragm is made thin, it can be improved. The sensitivity of the microphone, but its ability to resist falling is poor.

Summary of the invention

It is an object of the present invention to provide a new technical solution for a sensitive film.

According to a first aspect of the present invention, a sensitive film is provided, including a sensing portion located at a middle portion, a connecting portion at an edge, and an action portion between the sensing portion and the connecting portion; the sensing portion and the action The connecting portion is integrally formed; wherein the operating portion has a corrugated shape or a rectangular tooth shape; and a first reinforcing portion is further disposed at a position of the connecting portion.

Optionally, the extending direction of the operating portion is consistent with the extending direction of the sensing portion; or the operating portion is perpendicular to the sensing portion.

Optionally, a second reinforcing portion is disposed on the sensing portion.

Optionally, the first reinforcing portion is disposed at a lower end of the connecting portion, and the first reinforcing portion and the connecting portion are made of the same or different materials.

Optionally, the second reinforcing portion is disposed at a lower end of the sensing portion, and the second reinforcing portion and the sensing portion are made of the same or different materials.

Optionally, the first reinforcing portion and the second reinforcing portion are respectively stacked with the connecting portion and the sensing portion of the diaphragm by layer-by-layer deposition and etching.

Optionally, an end surface of the sensing portion is higher than an end surface of the action portion.

Optionally, a microporous structure for adjusting a vibration frequency of the operating portion is provided on the action portion.

The present invention also provides a MEMS microphone comprising a substrate having a back cavity on which a back electrode is disposed, and a sensitive film as described above, the sensitive film and the back electrode forming a plate capacitor structure.

Optionally, the sensitive film is located above the back pole to form a capacitive structure with the sensitive film on the top and the back pole; or

The sensitive film is located below the back pole, forming a capacitive structure in which the sensitive film is on the lower and back poles.

The sensitive film of the invention integrates the advantages of the traditional spring-type diaphragm and the full-membrane structure film, and is designed to provide a central-area full-plane sensing in the central region, which is comparable to the conventional curved deformation in the same displacement interval. Provides a larger amount of capacitance change, thereby improving the overall sensitivity; the action portion provided by the corrugated or rectangular teeth can provide a larger displacement amount for the sensing portion, thereby improving the sensitivity of the sensing portion; by being disposed at the connection portion The first reinforcing portion of the position can greatly improve the connection strength of the sensitive film, thereby improving the impact resistance of the sensitive film.

Other features and advantages of the present invention will become apparent from the Detailed Description of the <RTIgt;

DRAWINGS

The accompanying drawings, which are incorporated in FIG.

1 is a schematic structural view of a MEMS microphone of the present invention.

detailed description

Various exemplary embodiments of the present invention will now be described in detail with reference to the drawings. It should be noted that the relative arrangement of the components and steps, numerical expressions and numerical values set forth in the embodiments are not intended to limit the scope of the invention unless otherwise specified.

The following description of the at least one exemplary embodiment is merely illustrative and is in no way

Techniques and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques and devices should be considered as part of the specification.

In all of the examples shown and discussed herein, any specific values are to be construed as illustrative only and not as a limitation. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that similar reference numerals and letters indicate similar items in the following figures, and therefore, once an item is defined in one figure, it is not required to be further discussed in the subsequent figures.

In order to solve the problems existing in the prior art, the present invention provides a sensitive film which not only has high sensitivity, but also has high impact resistance.

Referring to Fig. 1, the present invention provides a sensitive film comprising a sensing portion 2c at a middle portion, a connecting portion 2a at an edge, and an action portion 2b between the sensing portion 2c and the connecting portion 2a; The film can be mounted on the substrate of the sensor through the connecting portion 2a, and the sensing portion 2c of the sensitive film is caused to vibrate or planarly displaced by the action portion 2b, thereby measuring corresponding data information.

The connecting portion 2a, the operating portion 2b, and the sensing portion 2c of the present invention are integrally formed, and can be formed by deposition or etching patterning techniques at the time of fabrication. Such a molding process is well known to those skilled in the art. The sensitive film may be a single crystal silicon, a polycrystalline silicon, a silicon nitride or a conductive metal material well known to those skilled in the art, or a laminated material in which a conductive material and a non-conductive material are stacked together.

The operating portion 2b of the present invention has a corrugated or rectangular tooth shape that is reciprocally bent, so that the operating portion 2b can have a constant elastic ability, and the sensing portion 2c is connected to the connecting portion 2a via the operating portion 2b. Together, the action portion 2b can provide a larger displacement amount for the sensing portion 2c; the sensing portion 2c can be made to provide a higher sensitivity output under the sensing conditions of the same displacement amount. The extending direction of the operating portion 2b may coincide with the extending direction of the sensing portion 2c. For example, the operating portion 2b and the sensing portion 2c each extend in the horizontal direction. In another preferred embodiment of the present invention, the action portion 2b is perpendicular to the sensing portion 2c. For example, the sensing portion 2c extends in a horizontal direction such that the sensing portion 2c can provide detection of a surface displacement, and the action portion 2b extends in a vertical direction so as not only to provide support for the sensing portion 2c, It is also possible to provide an elastic force for the action of the sensing portion 2c under the action of the outside.

The sensitive film of the present invention is further provided with a first reinforcing portion 6 at a position of the connecting portion 2a, and the first reinforcing portion 6 is preferably disposed on a side of the connecting portion 2a for connecting the substrate, for example, The lower end of the connecting portion 2a. The first reinforcing portion 6 may be made of the same material as the connecting portion 2a; a material different from the connecting portion 2a may be selected, for example, a silicon nitride material may be used. In a specific embodiment of the present invention, the sensitive film may have a thickness of 0.1 um to 3 um, and the first reinforcing portion 6 may have a thickness of 0.1 um to 3 um. At the time of manufacture, a film layer may be first deposited, and then the first reinforcing portion 6 is formed by etching, and then the film layer is continuously deposited, and the action portion 2b forming the diaphragm, the sensing portion 2c, and A connecting portion 2a located above the first reinforcing portion 6 and laminated with the first reinforcing portion 6.

The sensitive film of the present invention can provide a larger displacement amount for the sensing portion by the action portion having a corrugated shape or a rectangular tooth shape, thereby improving the sensitivity of the sensing portion as the surface displacement detection; A reinforcing portion can greatly increase the joint strength of the position of the sensitive film joint portion, thereby improving the impact resistance of the entire sensitive film.

In a preferred embodiment of the present invention, the second reinforcing portion 7 is disposed on the sensing portion 2c, and the second reinforcing portion 7 may be disposed at an upper end of the sensing portion 2c or may be disposed under the sensing portion 2c. On the end face. The second reinforcing portion 7 may be made of the same material as the sensitive film, or may be made of a material different from the sensitive film. The thickness of the position of the sensing portion 2c can be greatly increased by the second reinforcing portion 7, whereby the impact resistance of the sensing portion 2c can be improved. At the same time, the sensing portion 2c is reinforced by the second reinforcing portion 7, thereby improving the overall strength of the sensing portion 2c, so that the overall structure of the sensing portion 2c is relatively stable, and the sensing is performed by the middle thickening. The portion 2c can provide full-plane sensing of the central region, thereby providing a more accurate and stable detection surface for the corresponding sensor. In phase Compared with the traditional curved surface deformation, the same displacement interval can provide a larger amount of capacitance change, thereby improving the overall sensitivity.

In the sensitive film of the present invention, the first reinforcing portion 6 and the second reinforcing portion 7 may be located on the same layer and obtained by depositing and etching the same film layer, the connecting portion 2a, the operating portion 2b, and the sensing portion 2c. It can be obtained by depositing and etching another film layer. For example, a first film layer may be first deposited on the substrate, and the film layer is etched to form the first reinforcing portion 6 and the second reinforcing portion 7; and then the second film layer is continuously deposited. The second film layer covers the first reinforcing portion 6 and the second reinforcing portion 7, and the second film layer is etched to obtain the connecting portion 2a laminated with the first reinforcing portion 6. The sensing unit 2c laminated with the second reinforcing portion 7 and the operating portion 2b located between the connecting portion 2a and the sensing portion 2c. In this case, in order to make the post-deposition action portion 2b have a structure of corrugated or rectangular teeth, a corresponding groove can be formed on the substrate in advance, which is common knowledge of those skilled in the art, and is not specific here. Description.

In the sensitive film of the present invention, the connecting portion 2a, the operating portion 2b, and the sensing portion 2c may be located on the same horizontal surface or on different horizontal surfaces. For example, the end surface of the sensing portion 2c may be higher than the working portion 2b. The end face makes it possible to provide the second reinforcing portion 7 at the lower end of the sensing portion 2c.

In a preferred embodiment of the present invention, the action portion 2b is further provided with a microporous structure 8 disposed on the action portion 2b, so that the vibration frequency of the action portion 2b can be adjusted; for example, When the sensitive film is applied to the microphone, the low-frequency section of the microphone can be adjusted by providing the micro-hole structure 8 on the action portion 2b. Moreover, the microporous structure 8 can also be waterproof. The selection of the pore size and the number of the microporous structures 8 are common knowledge of those skilled in the art and will not be specifically described herein.

The present invention also provides a MEMS microphone comprising a substrate 1 having a back cavity on which a plate capacitor structure composed of the above-described sensitive film and the back electrode 3 is disposed. In a specific embodiment of the present invention, the panel capacitor structure is a capacitor structure in which the back electrode 3 is on and the sensitive film is under. Referring to FIG. 1, the first reinforcing portion 6 under the sensitive film connecting portion 2a is connected above the substrate 1 through the first insulating layer 5, and the edge position of the back electrode 3 is supported by the second insulating layer 4 in the sensitive portion. Above the film connecting portion 2a, the back electrode 3 and the sensing portion 2c of the sensitive film constitute a plate capacitor structure.

In another specific embodiment of the present invention, the panel capacitor structure may be sensitive a capacitor having a film on the upper and lower electrodes 3, the back electrode 3 being connected to the substrate 1. In order to ensure insulation between the back electrode 3 and the substrate 1, between the back electrode 3 and the substrate 1 An insulating layer is provided, which may be, for example, an insulating material well known to those skilled in the art such as silicon oxide. The first reinforcing portion 6 under the connecting portion 2a can be supported above the backing pole 3 through another insulating layer, so that a certain gap is formed between the sensing portion 2c of the sensitive film and the backing pole 3, and the sensing portion 2c is ensured A plate capacitor structure can be formed between the back poles 3.

The sensitive film of the present invention can be applied not only to a microphone but also to other capacitive, piezoresistive, piezoelectric, optical or moving coil sensors. For example, the sensitive film can be used as a sensitive film layer of a pressure sensor, a temperature sensor, and a gas sensor. When the external environmental information changes, the sensing portion in the driving sensitive film is displaced under the action of the action portion, thereby causing the environmental sensor. An electrical signal characterizing the external environment information can be output. The sensitive film can also be applied to various sensors that can be detected by plane displacement, such as an accelerometer, a gyroscope, an altimeter, a touch sensor, a micro-motion horn, a micro-motion vibrator, and a motor.

While the invention has been described in detail with reference to the specific embodiments of the present invention, it should be understood that It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

A sensitive film comprising: a sensing portion (2c) located at a middle portion, a connecting portion (2a) at an edge, and an action portion (2b) between the sensing portion (2c) and the connecting portion (2a) The sensing portion (2c), the operating portion (2b), and the connecting portion (2a) are integrally formed; wherein the operating portion (2b) is corrugated or rectangular-shaped; at the connecting portion ( The position of 2a) is also provided with a first reinforcing portion (6).
The sensitive film according to claim 1, wherein the extending direction of the action portion (2b) coincides with the extending direction of the sensing portion (2c); or the action portion (2b) The sensing portion (2c) is vertical.
The sensitive film according to claim 1, wherein a second reinforcing portion (7) is provided on the sensing portion (2c).
The sensitive film according to claim 3, wherein the first reinforcing portion (6) is disposed at a lower end of the connecting portion (2a), and the first reinforcing portion (6) and the connecting portion (2a) ) use the same or different materials.
The sensitive film according to claim 4, wherein the second reinforcing portion (7) is disposed at a lower end of the sensing portion (2c), and the second reinforcing portion (7) and the sensing portion (2c) Use the same or different materials.
The sensitive film according to claim 5, wherein the first reinforcing portion (6) and the second reinforcing portion (7) are respectively connected to the diaphragm (2a) and the sensing portion (2c) Stacked together by layer-by-layer deposition and etching.
The sensitive film according to claim 1, wherein an end surface of the sensing portion (2c) is higher than an end surface of the action portion (2b).
The sensitive film according to claim 1, wherein a microporous structure (8) for adjusting a vibration frequency of the operating portion (2b) is provided on the operating portion (2b).
A MEMS microphone comprising: a substrate (1) having a back cavity, a back electrode (3) disposed on the substrate (1), and the method of any one of claims 1 to 8 A sensitive film, the sensitive film and the back electrode (3) constitute a plate capacitor structure.
The MEMS microphone of claim 9 wherein said sensitive The film is located above the back electrode (3) to form a capacitive structure in which the sensitive film is on the upper and lower poles (3); or

The sensitive film is located below the back electrode (3), forming a capacitive structure of the sensitive film on the lower and back poles (3).