CN211959557U

CN211959557U - Microphone

Info

Publication number: CN211959557U
Application number: CN202020837898.9U
Authority: CN
Inventors: 孙恺; 荣根兰; 胡维
Original assignee: Memsensing Microsystems Suzhou China Co Ltd
Current assignee: Memsensing Microsystems Suzhou China Co Ltd
Priority date: 2020-05-19
Filing date: 2020-05-19
Publication date: 2020-11-17
Anticipated expiration: 2030-05-19

Abstract

The utility model relates to the technical field of microphones, and discloses a microphone, which comprises a substrate, and a vibrating diaphragm and a back plate which are sequentially formed above the substrate; a first sacrificial layer is arranged between the back plate and the vibrating diaphragm, and a conductive layer is arranged above the back plate; further comprising: the first groove is concavely arranged on the upper surface of the back plate; the back plate electrode is arranged in the first groove and is electrically connected with the conductive layer; the second groove penetrates through the back plate and the first sacrificial layer so as to expose at least part of the vibrating diaphragm; and the vibrating diaphragm electrode is arranged in the second groove and is electrically connected with the vibrating diaphragm. The utility model discloses a microphone directly forms backplate electrode in first recess and is connected with the conducting layer, and the vibrating diaphragm electrode forms in the second recess and vibrating diaphragm lug connection, and backplate plate electrode and vibrating diaphragm plate electrode are all concave to be located the microphone surface, compares with prior art, has reduced backplate electrode and vibrating diaphragm electrode and has taken place the probability of fish tail, scratch or wearing and tearing, has prolonged the life of microphone.

Description

Microphone

Technical Field

The utility model relates to a microphone technical field especially relates to a microphone.

Background

The Microphone of micro electromechanical system (MEMS Microphone for short) is a Microphone made based on MEMS technology, and comprises a vibrating diaphragm, a conductive plate and two electrodes, wherein one end of each electrode is connected with the vibrating diaphragm or the conductive plate, and the other end of each electrode is connected with a circuit board of an integrated circuit, thereby realizing the conversion of sound, mechanical and electrical signals. In the prior art, one electrode is directly and convexly arranged on the conductive plate and electrically connected with the conductive plate, and the other electrode is convexly arranged on the insulating layer and electrically connected with the vibrating diaphragm through a wire, so that the convexly arranged electrode is very easy to scratch, scratch or wear in the production or transportation process of the microphone, and the service life of the MEMS microphone is shortened.

SUMMERY OF THE UTILITY MODEL

Based on the above, an object of the utility model is to provide a microphone, guard electrode that can be better has reduced the probability of electrode fish tail, scratch or wearing and tearing.

In order to achieve the purpose, the utility model adopts the following technical proposal:

a microphone comprises a substrate, a vibrating diaphragm and a back plate which are sequentially formed above the substrate; a first sacrificial layer is arranged between the back plate and the vibrating diaphragm, and a conducting layer is arranged above the back plate; the microphone further includes: the first groove is concavely arranged on the upper surface of the back plate; the back plate electrode is arranged in the first groove and is electrically connected with the conducting layer; the second groove penetrates through the back plate and the first sacrificial layer so as to expose at least part of the diaphragm; and the vibrating diaphragm electrode is arranged in the second groove and is electrically connected with the vibrating diaphragm.

As a preferred scheme of the microphone, the back plate electrode is an aluminum electrode or a chrome gold electrode, and the diaphragm electrode is an aluminum electrode or a chrome gold electrode.

As a preferred scheme of microphone, the thickness of aluminium electrode is 0.5um-1.5um, the thickness of chromium gold electrode is 0.25um-0.5 um.

As a preferred scheme of the microphone, the depth of the first groove is 0.3um-1.5 um.

As a preferable scheme of the microphone, a sound hole is formed in the back plate, and the sound hole penetrates through the back plate and the conductive layer.

As a preferred scheme of the microphone, a second sacrificial layer is clamped between the substrate and the diaphragm, a back cavity is arranged in the middle of the substrate, the sound hole is opposite to the back cavity, and the middle of the diaphragm is clamped between the second sacrificial layer and the first sacrificial layer in a suspending manner.

As a preferred scheme of microphone, be equipped with on the first sacrificial layer with the back of the body chamber corresponds the first intercommunication chamber that sets up, be equipped with on the second sacrificial layer just to the second intercommunication chamber in first intercommunication chamber, the diameter in first intercommunication chamber is greater than the diameter in second intercommunication chamber, the middle part of vibrating diaphragm is located first intercommunication chamber with between the second intercommunication chamber.

As a preferable mode of the microphone, an anti-adhesion structure is provided on a surface of the back plate facing the first communication chamber to prevent the diaphragm from adhering to the back plate.

As a preferred scheme of the microphone, a plurality of release holes are formed in the diaphragm, and at least one release hole is opposite to the sound hole.

As a preferable scheme of the microphone, the plurality of release holes are annularly arranged with a fixed length as a radius around the center of the diaphragm.

As a preferable aspect of the microphone, the release holes are U-shaped release holes, circular release holes, polygonal release holes, or S-shaped release holes.

The utility model has the advantages that: the utility model discloses a microphone directly forms backplate electrode in first recess and is connected with the conducting layer, and the vibrating diaphragm electrode forms in the second recess and vibrating diaphragm lug connection, and backplate plate electrode and vibrating diaphragm plate electrode are all concave to be located the microphone surface, compares with prior art, has reduced backplate electrode and vibrating diaphragm electrode and has taken place the probability of fish tail, scratch or wearing and tearing, has prolonged the life of microphone.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.

Fig. 1 is a cross-sectional view of a microphone provided in an embodiment of the present invention in one direction;

fig. 2 is a cross-sectional view of a microphone provided in another embodiment of the present invention.

In the figure:

100. a substrate; 101. a back cavity;

200. vibrating diaphragm; 201. a release aperture;

300. a first sacrificial layer; 301. a first communicating chamber;

400. a back plate; 401. a first groove; 402. a second groove; 403. a sound hole; 41. a conductive layer; 42. an anti-sticking structure;

51. a back plate electrode; 52. a diaphragm electrode;

600. a second sacrificial layer; 601. a second communicating chamber.

Detailed Description

In order to make the technical problems, technical solutions and technical effects achieved by the present invention more clear, the embodiments of the present invention will be described in further detail with reference to the accompanying drawings, and obviously, the described embodiments are only some embodiments, not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Wherein the terms "first position" and "second position" are two different positions.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection or a removable connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The present embodiment provides a microphone, as shown in fig. 1 and fig. 2, including a substrate 100, a diaphragm 200 and a backplate 400 sequentially deposited on the substrate 100, the substrate 100 is a silicon substrate, the backplate 400 is a silicon oxide insulating layer, a first sacrificial layer 300 is disposed between the backplate 400 and the diaphragm 200, and a conductive layer 41 is disposed on the backplate 400. The microphone of this embodiment further includes a first groove 401, a backplate electrode 51, a second groove 402, and a diaphragm electrode 52, where the first groove 401 is concavely disposed on the upper surface of the backplate 400, the backplate electrode 51 is disposed in the first groove 401 and electrically connected to the conductive layer 41, the second groove 402 penetrates the backplate 400 and the first sacrificial layer 300 to expose at least a portion of the diaphragm 200, and the diaphragm electrode 52 is disposed in the second groove 402 and electrically connected to the diaphragm 200. The diaphragm 200 and the backplate electrode 51 are connected to the circuit board through the diaphragm electrode 52 and the backplate electrode 51, respectively, so as to realize the conversion of sound, mechanical and electrical signals.

Specifically, a conformal recess is formed at a first location of the first sacrificial layer 300, the backplate 400 is formed conformally over the first sacrificial layer 300 such that a first recess 401 is formed on the backplate 400, and the backplate electrode 51 is deposited within the first recess 401. Removing the backplate 400 and the first sacrificial layer 300 downward at a second position of the backplate 400 forms a first groove 401 capable of exposing a portion of the diaphragm 200, and the diaphragm electrode 52 is deposited in the first groove 401.

Preferably, the depth of the first groove 401 of the present embodiment is 0.3um to 1.5um, and the thickness of the back plate electrode 51 is smaller than the depth of the first groove 401. Of course, in other embodiments of the present invention, the depth of the first groove 401 is not limited to this limitation of the present embodiment, and may also be other depth values, specifically set according to actual needs.

According to the microphone provided by the embodiment, the back plate electrode 51 is directly deposited in the first groove 401 and connected with the conductive layer 41, the diaphragm electrode 52 is deposited in the second groove 402 and directly connected with the diaphragm 200, and the back plate electrode 51 plate and the diaphragm electrode 52 plate are both concavely arranged on the surface of the microphone.

Specifically, the back plate electrode 51 and the diaphragm electrode 52 of the present embodiment are both aluminum electrodes, and the thickness of the aluminum electrodes is between 0.5um and 1.5 um. Certainly, in other embodiments of the present invention, the back plate electrode 51 may also be a chrome gold electrode, or the diaphragm electrode 52 may be a chrome gold electrode, or the back plate electrode 51 and the diaphragm electrode 52 are chrome gold electrodes at the same time, the thickness of the chrome gold electrode is located between 0.25um and 0.5um, or the back plate electrode 51 and the diaphragm electrode 52 are made of other metal materials, and the thickness of the electrode is specifically set according to the actual needs of the user.

As shown in fig. 1 and fig. 2, a second sacrificial layer 600 is sandwiched between the substrate 100 and the diaphragm 200 in this embodiment, a back cavity 101 is disposed in the middle of the substrate 100, and the middle of the diaphragm 200 is sandwiched between the second sacrificial layer 600 and the first sacrificial layer 300 in a suspending manner. The back plate 400 of this embodiment is provided with a plurality of sound holes 403, and the sound holes 403 face the back cavity 101 and penetrate through the back plate 400 and the conductive layer 41. The design of the sound hole 403 on the backplate 400 is to transmit sound waves to the diaphragm 200 through the sound hole 403, the diaphragm 200 deforms under the action of the sound waves, so that the distance between the diaphragm 200 and the backplate 400 changes, the capacitance and voltage are changed, the circuit board is electrically connected with the backplate electrode 51 and the diaphragm electrode 52 which lead out electric signals from the backplate 400 and the diaphragm 200, and the capacitance change is converted into the change of voltage signals and output. When the diaphragm 200 is vibrated by sound waves, the air flow between the diaphragm 200 and the backplate 400 can be exhausted by the sound holes 403 distributed on the backplate 400, which is a source of noise. The sound holes 403 are formed in the back plate 400, and a certain open area is ensured, so that air between the diaphragm 200 and the back plate 400 can be smoothly discharged through the sound holes 403, noise is reduced, and the signal-to-noise ratio is improved.

Specifically, as shown in fig. 1 and fig. 2, a first communicating cavity 301 corresponding to the back cavity 101 is disposed on the first sacrificial layer 300, a second communicating cavity 601 facing the first communicating cavity 301 is disposed on the second sacrificial layer 600, a diameter of the first communicating cavity 301 is greater than a diameter of the second communicating cavity 601, and a middle portion of the diaphragm 200 is located between the first communicating cavity 301 and the second communicating cavity 601. Through making the diameter of first communicating chamber 301 be greater than the diameter of second communicating chamber 601, can reduce the restriction of first sacrificial layer 300 to vibrating diaphragm 200, promote whole vibrating diaphragm 200's uniformity, guarantee vibrating diaphragm 200's vibration performance, vibrating diaphragm 200's edge produces stress concentration when effectively avoiding vibrating, promotes microphone's performance and life. If the diameter of the first communicating chamber 301 is not larger than the diameter of the second communicating chamber 601, which is equivalent to thickening the edge of the diaphragm 200, the effective vibration area of the diaphragm 200 decreases, the uniformity of the entire diaphragm 200 deteriorates, and the performance of the microphone decreases.

Because the backplate 400 is thin, the backplate 400 above the first communicating cavity 301 is easily bonded with the diaphragm 200, so that the backplate 400 and the diaphragm 200 are bonded together to influence sound production, and in order to prevent the bonding between the backplate 400 and the diaphragm 200, as shown in fig. 1 and fig. 2, an anti-sticking structure 42 is disposed on one side of the backplate 400 close to the first sacrificial layer 300, and the anti-sticking structure 42 can effectively prevent the diaphragm 200 from being in a vibrating process, wherein van der waals force between the diaphragm 200 and the backplate 400 is greater than restoring force of a vibrating part of the diaphragm 200, so that the diaphragm 200 cannot return to a balance position. Specifically, anti-sticking structure 42 of this embodiment is a plurality of projection, and the projection stretches into in the first communicating cavity 301 of first sacrificial layer 300 and set up with vibrating diaphragm 200 interval, even the projection bonds with vibrating diaphragm 200, but because area of contact between them is less for the projection separates with vibrating diaphragm 200 very easily, has reduced both bonding probabilities greatly. Of course, in other embodiments of the present invention, the anti-sticking structure 42 may also be a plurality of square bumps or a plurality of protrusions with other shapes, and is specifically configured according to actual needs.

As shown in fig. 1 and fig. 2, a plurality of release holes 201 are formed in a diaphragm 200 of this embodiment, each release hole 201 is a U-shaped release hole in mirror symmetry, the plurality of release holes 201 are annularly arranged around a center of the diaphragm 200 and a fixed length as a radius, wherein at least one release hole 201 faces a sound hole 403. After the air enters the first communicating cavity 301 through the sound hole 403, a certain pressure is generated on the diaphragm 200, in order to prevent the diaphragm 200 from being damaged due to the excessive air pressure acting on the diaphragm 200, the release hole 201 is arranged to release a part of the pressure, so that the probability of the diaphragm 200 being damaged due to the excessive air pressure is reduced, and the service life of the microphone is prolonged. Specifically, in the packaging process and the using process of the microphone chip, if the environment changes, for example, when the microphone falls, the microphone faces sharply changing sound pressure or airflow, the release holes 201 can quickly and uniformly adjust the air pressure between the back plate 400 and the diaphragm 200 corresponding to the release holes 201 to release the pressure, so that the stress applied to the diaphragm 200 is uniformly distributed, and the diaphragm 200 of the microphone is ensured not to break. In other embodiments of the present invention, the releasing hole 201 may also be a circular releasing hole, a polygonal releasing hole or an S-shaped releasing hole, which is specifically selected according to actual needs.

It should be noted that the number of the release holes 201 should be greater than or equal to 4 and less than or equal to 48, which not only can achieve the purpose of quickly exhausting the air between the backplate 400 and the diaphragm 200 to release the pressure, adjust the air pressure between the backplate 400 and the diaphragm 200 to ensure that the diaphragm 200 of the microphone does not break, but also can ensure that the damping of the release holes 201 to the air is in a proper range, so that the sensitivity of the microphone is moderate. When the number of the release holes 201 is less than 4, air between the backplate 400 and the diaphragm 200 cannot be rapidly discharged to release the pressure, and the air pressure between the backplate 400 and the diaphragm 200 is adjusted. When the number of the release holes 201 is greater than 48, the total opening area of the release holes 201 is too large, and the damping of the air by the release holes 201 is too small during the process of discharging the air between the backplate 400 and the diaphragm 200 through the release holes 201, so that the sensitivity of the microphone is reduced.

In the description herein, references to the description of "some embodiments," "other embodiments," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above description is only for the preferred embodiment of the present invention, and for those skilled in the art, there are variations on the detailed description and the application scope according to the idea of the present invention, and the content of the description should not be construed as a limitation to the present invention.

Claims

1. A microphone comprises a substrate (100), and a diaphragm (200) and a backplate (400) which are sequentially formed above the substrate (100); a first sacrificial layer (300) is arranged between the back plate (400) and the diaphragm (200), and a conducting layer (41) is arranged above the back plate (400); characterized in that the microphone further comprises:

the first groove (401) is concavely arranged on the upper surface of the back plate (400);

a back plate electrode (51) arranged in the first groove (401) and electrically connected with the conductive layer (41);

a second groove (402) penetrating the backplate (400) and the first sacrificial layer (300) to expose at least a portion of the diaphragm (200);

and the diaphragm electrode (52) is arranged in the second groove (402) and is electrically connected with the diaphragm (200).

2. The microphone of claim 1, wherein the backplate electrode (51) is an aluminum electrode or a chrome-gold electrode, and the diaphragm electrode (52) is an aluminum electrode or a chrome-gold electrode.

3. The microphone of claim 2, wherein the aluminum electrode has a thickness of 0.5um to 1.5um and the chrome gold electrode has a thickness of 0.25um to 0.5 um.

4. The microphone of claim 1, wherein the depth of the first groove (401) is 0.3um-1.5 um.

5. Microphone according to any of claims 1 to 4, characterized by the fact that the back plate (400) is provided with sound holes (403), the sound holes (403) penetrating the back plate (400) and the conductive layer (41).

6. The microphone according to claim 5, wherein a second sacrificial layer (600) is sandwiched between the substrate (100) and the diaphragm (200), a back cavity (101) is disposed in the middle of the substrate (100), the sound hole (403) is aligned with the back cavity (101), and the middle of the diaphragm (200) is sandwiched between the second sacrificial layer (600) and the first sacrificial layer (300) in a suspended manner.

7. The microphone according to claim 6, wherein a first communicating cavity (301) corresponding to the back cavity (101) is formed in the first sacrificial layer (300), a second communicating cavity (601) opposite to the first communicating cavity (301) is formed in the second sacrificial layer (600), the diameter of the first communicating cavity (301) is larger than that of the second communicating cavity (601), and the middle portion of the diaphragm (200) is located between the first communicating cavity (301) and the second communicating cavity (601).

8. Microphone according to claim 7, characterized by the fact that the backplate (400) is provided with an anti-adhesive structure (42) on its surface facing the first communication cavity (301) to prevent the diaphragm (200) from adhering to the backplate (400).

9. The microphone of claim 5, wherein the diaphragm (200) is provided with a plurality of release holes (201), and at least one release hole (201) is opposite to the sound hole (403).

10. The microphone of claim 9, wherein the plurality of release holes (201) are arranged in a ring shape with a fixed length as a radius, centered at the center of the diaphragm (200).

11. The microphone of claim 10, wherein the release hole (201) is a U-shaped release hole, a circular release hole, a polygonal release hole, or an S-shaped release hole.