CN206908774U - One kind sensing diaphragm and MEMS microphone - Google Patents

Abstract

The utility model relates to a sensing diaphragm and a MEMS microphone. A plurality of comb teeth are formed at the edge of the sensing diaphragm, and the plurality of comb teeth are distributed in the circumferential direction of the sensing diaphragm at intervals. above; wherein, the position between two adjacent comb-tooth parts on the sensing diaphragm is a connection part for connection. In the microphone of the utility model, since a gap connected to the outside world is formed between the comb tooth area of the sensing diaphragm and the substrate, the sound pressure received by the sensing diaphragm can be quickly released through the gap to quickly balance the inside and outside of the microphone. chamber air pressure. Moreover, the comb tooth part can be deformed according to its own pressure, so that the size of the pressure relief path can be adjusted in real time according to the overload sound pressure received, so as to protect the sensing diaphragm.

Description

A sensing diaphragm and MEMS microphone

technical field

The utility model relates to a sensing diaphragm, in particular to a sensing diaphragm suitable for sound generation; the utility model also relates to a MEMS microphone.

Background technique

MEMS sensing components have been widely used in consumer electronics products. How to speed up the product production process is the focus of component suppliers. For example, the dust generated during the production and assembly of mobile phones is directly cleaned by air guns. The lowest cost option. Therefore, for MEMS sensors, it is necessary to propose a large-pressure or atmospheric-pressure anti-blow improvement plan to avoid rupture and failure of the microphone due to air gun cleaning during the assembly process.

The current improvement solution is to provide a pressure relief hole or a pressure relief valve structure on the sensing diaphragm of the MEMS microphone. But the structure of the pressure relief hole will reduce the effective area of the sensing diaphragm. The pressure relief valve structure set in the middle area of the sensing diaphragm will be limited by size, and its pressure relief capacity is limited; it will also directly affect the vibration characteristics of the sensing diaphragm, especially the low frequency characteristics of the sensing diaphragm; The dynamic stability of the diaphragm is relatively poor.

Utility model content

One object of the present utility model is to provide a sensing diaphragm.

According to one aspect of the present utility model, a sensing diaphragm is provided, and a plurality of comb teeth are formed at the edge of the sensing diaphragm, and the plurality of comb teeth are distributed at intervals around the sensing diaphragm. In the direction; wherein, the position between two adjacent comb-tooth parts on the sensing diaphragm is a connection part for connection.

Optionally, the sensing diaphragm includes a sensing diaphragm main body, the connecting portion is a radial protrusion extending outward from the edge of the sensing diaphragm main body, and the comb teeth are arranged on the sensing diaphragm main body The upper part is located between two adjacent connecting parts.

Optionally, each of the comb teeth includes at least one air leakage valve flap formed by etching the main body of the sensing diaphragm.

Optionally, the air release valve flap is rectangular, fan-shaped, elliptical, trapezoidal or S-shaped.

Optionally, the main body of the sensing diaphragm and the connection part are integrally formed by MEMS technology.

Optionally, the free end of the comb-tooth portion extends to the outer edge of the sensing diaphragm, and is flush with the outer edge of the sensing diaphragm, or is retracted relative to the outer edge of the sensing diaphragm .

Optionally, the free end of the comb tooth part is radially protruding relative to the outer edge of the sensing diaphragm.

According to another aspect of the present invention, there is also provided a MEMS microphone, comprising a substrate with a back cavity, a back electrode above the substrate, and the above-mentioned sensing diaphragm.

Optionally, the connection between two adjacent comb-tooth parts on the sensing diaphragm is connected to the substrate through an insulating layer; the comb-tooth parts on the sensing diaphragm are completely suspended on the back of the substrate. Above the cavity, and between the area of the comb tooth portion on the sensing diaphragm and the substrate, a gap for air flow is formed.

Optionally, the shape of the back electrode is consistent with that of the sensing diaphragm.

In the microphone of the utility model, since a gap connected to the outside world is formed between the comb tooth area of the sensing diaphragm and the substrate, the sound pressure received by the sensing diaphragm can be quickly released through the gap to quickly balance the inside and outside of the microphone. chamber air pressure. Moreover, the comb tooth part can be deformed according to its own pressure, so that the size of the pressure relief path can be adjusted in real time according to the overload sound pressure received, so as to protect the sensing diaphragm.

Other features and advantages of the present invention will become clear from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings.

Description of drawings

The accompanying drawings, which constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

Fig. 1 is a cross-sectional view of the microphone of the present invention from the position where the sensing diaphragm is connected to the substrate.

Fig. 2 is a schematic structural diagram of the sensing diaphragm of the present invention.

Fig. 3 is a partially enlarged view of the comb tooth part in Fig. 2 .

4 to 5 are two different operating states of the microphone of the present invention.

Fig. 6 is a schematic diagram of another implementation structure of the sensing diaphragm of the present invention.

detailed description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature, and in no way serves as any limitation of the invention and its application or use.

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

In all examples shown and discussed herein, any specific values should be construed as exemplary only, and not as limitations. Therefore, other instances of the exemplary embodiment may have different values.

It should be noted that like numbers and letters denote similar items in the following figures, therefore, once an item is defined in one figure, it does not require further discussion in subsequent figures.

The utility model provides a sensing diaphragm, which can be a sensing diaphragm applied in a microphone structure, or a sensitive film applied in other sensor structures, such as a sensitive film layer in a pressure sensor or a gas sensor . The structures, materials, and application environments of these sensing diaphragms belong to common knowledge in the field of various sensors, and will not be described in detail here.

For the convenience of expression, the microphone is taken as an example to describe the technical solution of the present invention in detail. It should be understood that for those skilled in the art, it can also be various sensors with other structures.

Referring to FIG. 1 , the utility model provides a MEMS microphone, which includes a substrate 1b, a sensing diaphragm 2b and a back electrode 5b located above the substrate 1b. A back cavity is formed in the middle region of the substrate 1b, and the sensing diaphragm 2b is supported above the substrate 1b through the first insulating layer 3b, thereby ensuring the insulation between the sensing diaphragm 2b and the substrate 1b, and making The middle region of the sensing diaphragm 2b is suspended above the back cavity of the substrate 1b. The back electrode 5b is provided with a plurality of through holes 50b, which are supported above the sensing diaphragm 2b through the second insulating layer 4b. The second insulating layer 4b can not only ensure the contact between the back electrode 5b and the sensing diaphragm 2b. Mutual insulation can also make a certain gap between the back electrode 5b and the sensing diaphragm 2b. A capacitor structure capable of converting sound signals into electrical signals is formed between the back electrode 5b and the sensing diaphragm 2b.

The microphone of the utility model is manufactured by MEMS technology, the substrate 1b can be made of monocrystalline silicon, the sensing diaphragm 2b and the back electrode 5b can be made of polysilicon, and the first insulating layer 3b and the second insulating layer 4b can be made of two The silicon oxide material, the structure of the microphone and its manufacturing process all belong to the common knowledge of those skilled in the art, and will not be described in detail here.

Referring to Fig. 2 and Fig. 3, the sensing diaphragm 2b provided by the present invention has a plurality of comb teeth 22b formed at its edge, and the comb teeth 22b may be formed by etching at the edge of the sensing diaphragm 2b At least one vent valve disc 220b. The number of the air-discharging valve disc 220b may be one, two, three or more, depending on actual design requirements. The air release valve flap 220b may be in a rectangular, fan-shaped, elliptical, trapezoidal or S-shaped air release valve structure known to those skilled in the art.

The comb tooth portion 22b of the present invention can be arranged inside the sensing diaphragm 2b, for example, the air leakage valve disc 220b is formed at the edge region of the sensing diaphragm 2b, and its free end is still located in the sensing diaphragm 2b.

In another specific embodiment of the present utility model, the free end of the comb tooth portion 22b extends to the outer edge of the sensing diaphragm 2b, and during manufacture, the etched slit penetrates the edge of the sensing diaphragm 2b, thereby The air release valve flap 220b is formed, and the free end of the air release valve flap 220b is released, as shown in FIG. 2 and FIG. 3 . The free end of the air release valve disc 220b of the utility model can be flush with the outer edge of the sensing diaphragm 2b, that is to say, the radial dimension from the center of the sensing diaphragm 2b to the free end of the air releasing valve disc 220b is the same as the center of the sensing diaphragm 2b. The radial dimension to the edge of the sensing diaphragm 2b is consistent. It can also be that the free end of the air release valve flap 220b of the present invention is in a radially retracted state relative to the outer edge of the sensing diaphragm 2b, that is to say, the radial direction from the center of the sensing diaphragm 2b to the free end of the air release valve flap 220b The dimension is smaller than the radial dimension from the center of the sensing diaphragm 2b to the edge of the sensing diaphragm 2b.

Of course, for those skilled in the art, the free end of the comb tooth portion 22b may also be radially protruding relative to the outer edge of the sensing diaphragm 2b. That is to say, the free end of the comb tooth portion 22b extends to the outside of the edge of the sensing diaphragm 2b, as shown in FIG. 6 .

The plurality of comb teeth 22b of the present invention are distributed at intervals in the circumferential direction of the sensing diaphragm 2b, so as to realize the uniformity of pressure relief in the peripheral direction of the sensing diaphragm 2b. For example, when the sensing diaphragm 2b is circular, the plurality of comb portions 22b may be evenly distributed in the circumferential direction of the sensing diaphragm 2b. The number of comb teeth 22b can be determined according to actual needs, for example, six as shown in FIG. 2 can be selected.

In the MEMS microphone of the present utility model, the position between two adjacent comb tooth parts 22b on the sensing diaphragm 2b is the connecting part 21b for connection. In the MEMS microphone structure, the connection part 21b is connected to the substrate 1b through the first insulating layer 3b, so as to connect and support the sensing diaphragm 2b on the substrate 1b. The connection point between the sensing diaphragm 2b and the substrate 1b is located between two adjacent comb portions 22b, so that the sensing diaphragm 2b is suspended above the substrate 1b except for the connecting portion 21b.

In the MEMS microphone of the present utility model, the comb tooth portion 22b on the sensing diaphragm 2b is completely suspended above the back chamber of the substrate 1b. Since the comb-tooth portion 22b of the sensing diaphragm 2b is completely suspended above the back cavity of the substrate 1b, this makes a gap for air flow to be formed between the area of the comb-tooth portion 22b on the sensing diaphragm 2b and the substrate 1b. Notch 6b.

Fig. 1 is a cross-sectional view of the microphone of the present invention along the connection position of the sensing diaphragm 2b and the substrate 1b, and Fig. 4 is a cross-sectional view of the microphone of the present invention along the position of the comb tooth part 22b of the sensing diaphragm 2b. The comb tooth portion 22b area on the edge of the sensing diaphragm 2b is suspended above the back cavity, which allows the gap 6b between the comb tooth portion 22b edge and the substrate 1b to be connected to the outside of the microphone, thereby facilitating pressure relief.

The sensing diaphragm 2b of the present utility model can be a circular sensing diaphragm. In a preferred embodiment of the present utility model, referring to FIG. 2, the sensing diaphragm 2b includes a sensing diaphragm main body 20b, so The connecting portion 21b is a radial protrusion extending outward from the edge of the sensing diaphragm main body 2b, so that the entire sensing diaphragm 2b is in the shape of a gear. The connecting portion 21b of the sensing diaphragm 2b is connected to the substrate 1b through the first insulating layer 3b, so as to realize the support and connection of the sensing diaphragm 2b on the substrate 1b as a whole.

The comb-tooth portion 22b is formed on the sensing diaphragm main body 20b between two adjacent connecting portions 21b. The sensing diaphragm main body 20b, connecting portion 21b, and comb tooth portion 22b of the present invention can all be formed on the same sensing diaphragm layer by etching. This MEMS process belongs to the common knowledge of those skilled in the art. This is no longer specified.

The structural design of the notch 6b of the utility model enables it to have two operating states when the pressure is released, refer to Fig. 4 to Fig. 5 .

Figure 4 shows the first operating state of the notch 6b of the present invention. When the sensing diaphragm 2b is in a normal working state, the airflow will flow out through the notch 6b, so as to meet the requirement of adjusting the low-frequency performance of the microphone.

Figure 5 shows the second operating state of the notch 6b of the present invention. When the sensing diaphragm 2b is subjected to overloaded sound pressure, the comb tooth part 22b on the sensing diaphragm 2b will be bulged, so that the comb teeth The gap 6b between the portion 22b and the substrate 1b forms a flaring structure, so as to facilitate rapid pressure release and ensure that the sensing diaphragm 2b is not damaged by the overload sound pressure.

In the microphone of the present invention, since a gap 6b communicating with the outside world is formed between the comb tooth portion 22b area of the sensing diaphragm 2b and the substrate 1b, the sound pressure received by the sensing diaphragm 2b can be quickly released through the gap 6b , to quickly equalize the air pressure inside and outside the microphone cavity. Moreover, the comb tooth part 22b can be deformed according to its own pressure, so that the size of the pressure relief path can be adjusted in real time according to the overload sound pressure received, so as to protect the sensing diaphragm 2b.

Although some specific embodiments of the present utility model have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration, rather than limiting the scope of the present utility model. It should be understood by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the invention is defined by the appended claims.

Claims (10)

1. one kind sensing diaphragm (2b), it is characterised in that：In the marginal position for sensing diaphragm (2b) formed with multiple broach Portion (22b), the multiple comb portion (22b) are distributed in the circumferential direction of sensing diaphragm (2b)；Wherein, the sensing film Position on piece (2b) between two neighboring comb portion (22b) is the connecting portion (21b) for connection.

2. sensing diaphragm (2b) according to claim 1, it is characterised in that：The sensing diaphragm (2b) includes sensing diaphragm Main body (20b), the connecting portion (21b) are to be outwardly extending diametrically projection, the broach from sensing diaphragm main body (20b) edge Portion (22b) is arranged on the position between two neighboring connecting portion (21b) on sensing diaphragm main body (20b).

3. sensing diaphragm (2b) according to claim 2, it is characterised in that：Each comb portion (22b) is included at least One discouraged flap (220b) formed by etching sensing diaphragm main body (20b).

4. sensing diaphragm according to claim 3, it is characterised in that：The discouraged flap (220b) is rectangular, fan-shaped, ellipse Circular, trapezoidal or S types.

5. sensing diaphragm according to claim 2, it is characterised in that：The sensing diaphragm main body (20b) and connecting portion (21b) is integrally formed by MEMS technology.

6. the sensing diaphragm according to any one of claim 1 to 5, it is characterised in that：The free end of the comb portion (22b) The outer ledge of sensing diaphragm (2b) is extended to, and is flushed with the outer ledge of the sensing diaphragm (2b), or relative to sense The outer ledge for surveying diaphragm (2b) is in inside contract state.

7. the sensing diaphragm (2b) according to any one of claim 1 to 5, it is characterised in that：The comb portion (22b) from By holding the outer ledge radially raised position relative to sensing diaphragm (2b).

A kind of 8. MEMS microphone, it is characterised in that：Including the substrate (1b) with back of the body chamber and above substrate (1b) Backplane (5b), the sensing diaphragm (2b) as described in any one of claim 1 to 7.

9. MEMS microphone according to claim 8, it is characterised in that：Two neighboring broach on the sensing diaphragm (2b) Connecting portion (21b) between portion (22b) is connected on substrate (1b) by insulating barrier；Comb portion on the sensing diaphragm (2b) (22b) is suspended at the top of substrate (1b) back of the body chamber completely, and senses region and the substrate (1b) of diaphragm (2b) upper comb dent portion (22b) Between constitute the breach (6b) that passes through of supply stream.

10. MEMS microphone according to claim 9, it is characterised in that：The backplane (5b) and sensing diaphragm (2b) Shape is consistent.