CN115942167A - Antifouling microphone chip and sound collection device - Google Patents

Abstract

The embodiment of the application provides an antifouling microphone chip and a sound collection device. The antifouling microphone chip comprises a substrate, an antifouling net, a vibrating diaphragm and a back plate which are sequentially stacked; the substrate is provided with a back cavity penetrating through two sides of the substrate, the orthographic projection of the back cavity on a first plane is positioned within the orthographic projection of the antifouling net on the first plane, and the first plane is the plane where the substrate is positioned; a first air gap is formed between the antifouling net and the diaphragm; a second air gap is arranged between the diaphragm and the back plate. The embodiment of the application realizes adding antifouling net in the back cavity of microphone chip, can effectively prevent external dust, water, the inside environment that filth such as oil got into the microphone chip, the inside vibrating diaphragm of effective separation microphone chip, important electroacoustics structures such as backplate and the possible contact of external filth, and then effectively reduce the probability that the electroacoustics structure of microphone chip inside received erosion or damage, improve the acoustoelectric conversion quality of microphone chip, the life-span of extension microphone chip.

Description

Antifouling microphone chip and sound collection device

Technical Field

The application relates to the technical field of sound-electricity conversion, in particular to an antifouling microphone chip and a sound collection device.

Background

In order to pick up sound, the back cavity of the microphone chip is usually in direct communication with the outside, and there is no anti-fouling structure between the internal environment of the microphone chip and the outside. For example, in an application scenario of a TWS (True Wireless Stereo) headset, a sound inlet hole of a microphone chip is closely connected to a sound inlet hole on the headset, that is, a back cavity of the microphone chip is directly communicated with the outside, and external dirt such as dust, water, oil and the like may enter an internal environment of the microphone chip through the back cavity of the microphone chip and directly contact important electroacoustic structures such as a diaphragm and a back plate inside the microphone chip, thereby corroding or damaging the electroacoustic structures inside the microphone chip.

Disclosure of Invention

This application provides an antifouling microphone chip and sound collection system to the shortcoming of current mode for solve prior art and have the technical problem that there is not antifouling structure between the internal environment of microphone chip and the external world.

In a first aspect, an embodiment of the present application provides an anti-fouling microphone chip, including a substrate, an anti-fouling mesh, a diaphragm, and a back plate, which are stacked in sequence;

the substrate is provided with a back cavity running through two sides of the substrate, the orthographic projection of the back cavity on the first plane is positioned within the orthographic projection of the antifouling net on the first plane, and the first plane is the plane where the substrate is;

a first air gap is formed between the antifouling net and the diaphragm;

a second air gap is arranged between the diaphragm and the back plate.

In one embodiment, the pore size of the anti-fouling web is no greater than 6 microns;

and/or the antifouling net has a pore depth of not less than 1 micron and not more than 3.5 microns.

In one embodiment, in the non-operating state, the minimum distance between the diaphragm and the anti-fouling mesh is no greater than the pore size of the anti-fouling mesh.

In one embodiment, the difference between the pore size of the anti-smudge mesh and the minimum distance between the diaphragm and the anti-smudge mesh is not less than 0.2 microns and not more than 1 micron.

In one embodiment, the diaphragm includes a pedestal portion and a vibrating portion connected to each other;

the foundation pile part is positioned on one side of the antifouling net far away from the base plate;

the vibration part is a convex structure close to the back plate, and one side of the vibration part facing the antifouling net is enclosed to form at least part of first air gaps.

In one embodiment, an orthographic projection of the back cavity on the first plane is located within an orthographic projection of the vibrating portion on the first plane.

In one embodiment, the vibrating portion has a pressure equalizing hole communicating the first air gap and the second air gap.

In one embodiment, the substrate comprises a laminated silicon-based layer and an insulating substrate layer;

the silicon substrate layer and the insulating substrate layer are respectively provided with a first through hole and a second through hole, and the first through hole and the second through hole are correspondingly communicated to form a back cavity of the substrate, which penetrates through two sides of the substrate;

one side of the insulating substrate layer, which is far away from the base plate, is provided with a limiting groove;

the antifouling net contacts one side of the insulating substrate layer far away from the base plate and contacts with at least part of the limiting groove.

In one embodiment, the anti-fouling microphone chip further comprises: a support structure located between the substrate and the back plate;

the vibrating diaphragm, the supporting structure and the back plate are enclosed to form a second air gap.

In a second aspect, an embodiment of the present application provides a sound collection device, including: the anti-fouling microphone chip as provided in the first aspect.

The beneficial technical effects brought by the technical scheme provided by the embodiment of the application comprise: add antifouling net in the dorsal cavity of microphone chip, can effectively prevent external filth such as dust, water, oil and get into the internal environment of microphone chip, important electro-acoustic structures such as the inside vibrating diaphragm of effective separation microphone chip, back polar plate and the possible contact of external filth, and then effectively reduce the probability that the inside electro-acoustic structure of microphone chip received erosion or damage, improve the acoustoelectric conversion quality of microphone chip, prolong the life-span of microphone chip.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

The foregoing and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic structural diagram of a first implementation manner of an anti-fouling microphone chip provided in an embodiment of the present application;

fig. 2 is a schematic structural diagram of a second embodiment of an anti-fouling microphone chip according to an embodiment of the present application;

fig. 3 is a schematic structural diagram of a third implementation manner of an anti-fouling microphone chip provided in an embodiment of the present application;

fig. 4 is a schematic structural diagram of an insulating substrate layer in an anti-fouling microphone chip according to an embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of a back plate in an anti-fouling microphone chip according to an embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of a supporting structure in an anti-fouling microphone chip according to an embodiment of the present application;

fig. 7 is an enlarged schematic view of a structure in fig. 6.

In the figure:

100-antifouling microphone chip; 100 a-a first air gap; 100 b-a second air gap;

110-a substrate; 110 a-a back cavity;

a 111-si based layer; 111 a-a first via;

112-an insulating substrate layer; 112 a-a second via; 112 b-a limiting groove;

120-a diaphragm; 120 a-pressure equalizing hole; 121-stub portion; 122-a vibrating portion;

130-a back plate; 130 a-sound-permeable aperture;

131-a first insulating layer; 131 a-a first acoustically transparent aperture; 132 — a first conductive layer; 132 a-a second acoustically transparent aperture; 133-a second insulating layer; 133 a-a third acoustically transparent aperture;

140-a support structure;

141-sacrificial material foundation piles;

142-an isolation layer; 1421-third insulating layer; 1422-second conductive layer; 1423 — fourth insulating layer; 150-antifouling net.

Detailed Description

Reference will now be made in detail to the present application, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar parts or parts having the same or similar functions throughout. In addition, if a detailed description of the known art is not necessary for illustrating the features of the present application, it is omitted. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

It will be understood by those within the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or wirelessly coupled. As used herein, the term "and/or" includes all or any element and all combinations of one or more of the associated listed items.

The inventor of the application researches and discovers that in order to pick up sound, the back cavity of the microphone chip is generally directly communicated with the outside, no antifouling structure exists between the internal environment of the microphone chip and the outside, external dirt such as dust, water and oil can enter the internal environment of the microphone chip through the back cavity of the microphone chip, and the dirt directly contacts with important electroacoustic structures such as a vibrating diaphragm and a back plate inside the microphone chip, so that the electroacoustic structures inside the microphone chip are corroded or damaged.

The application provides an antifouling microphone chip and sound collection system, aims at solving the technical problems in the prior art.

The following describes the technical solutions of the present application and how to solve the above technical problems with specific embodiments.

The embodiment of the application provides an antifouling microphone chip 100, and a schematic structural diagram of the antifouling microphone chip 100 is shown in fig. 1, and the antifouling microphone chip includes a substrate 110, an antifouling net 150, a diaphragm 120, and a back plate 130, which are sequentially stacked.

The substrate 110 has a back cavity 110a penetrating through two sides of the substrate, and an orthographic projection of the back cavity 110a on a first plane is positioned in an orthographic projection of the anti-fouling net 150 on the first plane, and the first plane is a plane where the substrate 110 is positioned.

The anti-contamination net 150 and the diaphragm 120 have a first air gap 100a therebetween.

A second air gap 100b is provided between the diaphragm 120 and the back plate 130.

In this embodiment, the anti-fouling net 150 is additionally disposed in the back cavity 110a of the microphone chip, so as to effectively prevent external dirt such as dust, water, oil, and the like from entering the internal environment of the microphone chip, and effectively prevent the important electro-acoustic structures such as the diaphragm 120 and the back plate 130 inside the microphone chip from possibly contacting the external dirt, thereby effectively reducing the probability that the electro-acoustic structures inside the microphone chip are corroded or damaged, improving the quality of acoustic-electric conversion of the microphone chip, and prolonging the life of the microphone chip.

The sound wave can normally pass through the anti-fouling net 150, that is, the external sound wave can sequentially pass through the back cavity 110a of the anti-fouling microphone chip 100, the anti-fouling net 150, the first air gap 100a between the anti-fouling net 150 and the vibrating diaphragm 120 and then reach the vibrating diaphragm 120, so that the vibrating diaphragm 120 is bent and deformed under the action of the sound wave, a second air gap 100b between the vibrating diaphragm 120 and the back plate 130 is caused to change, further, the capacitance between the vibrating diaphragm 120 and the back plate 130 is changed, and the sound wave is converted into an electric signal. The first air gap 100a and the second air gap 100b provide a deformation space for the diaphragm 120.

In some embodiments, the diaphragm 120 may be made of a polysilicon material.

In some embodiments, the thickness of the diaphragm 120 is not greater than 1 μm, so that the diaphragm 120 can be deformed by the sound wave with a smaller intensity, and the sensitivity is higher.

In some embodiments, the first and second air gaps 100a and 100b, respectively, may be several microns, i.e., microns.

The inventors of the present application consider that the antifouling microphone chip 100 provided by the present application needs to effectively prevent external dirt such as dust, water, oil, etc. from entering the internal environment of the microphone chip. For this reason, the present application provides three possible implementations for the anti-fouling microphone chip 100 as follows:

in a first possible implementation, the pore size of the anti-fouling mesh 150 is no greater than 6 microns.

In this embodiment, the anti-fouling net 150 employs micro pores with pore size not larger than 6 microns, which is beneficial to prevent solid contaminants such as dust with particle size larger than 6 microns from entering the first air gap 100a, and such micro pores can also form a barrier to liquid contaminants under certain pressure by utilizing liquid surface tension, for example, can prevent water with water pressure not larger than 1 meter from entering the first air gap 100a. Thereby effectively blocking the important electroacoustic structures such as the diaphragm 120 and the back plate 130 inside the microphone chip from possible contact with external dirt.

In a second possible implementation, the anti-fouling mesh 150 has a pore depth of not less than 1 micron and not more than 3.5 microns.

In this embodiment, the anti-fouling net 150 has micropores with a pore depth of not less than 1 micron and not more than 3.5 microns, and can enhance the barrier effect against the liquid contaminants by using the capillary effect.

In a third possible implementation, in the non-operating state, the minimum distance between the diaphragm 120 and the anti-fouling mesh 150 is not greater than the pore size of the anti-fouling mesh 150. Thus, when the antifouling microphone chip 100 is in an operating state, and the diaphragm 120 is subjected to bending deformation under the action of sound waves, the thickness of the first air gap 100a can be equal to or slightly larger than the aperture of the antifouling net 150, which is beneficial to that when some solid pollutants with particle sizes smaller than the aperture of the antifouling net 150 get over the antifouling net 150 and reach the first air gap 100a, the normal deformation of the diaphragm 120 is not influenced, that is, the acoustoelectric conversion quality of the microphone chip is ensured.

In some embodiments, in the non-operating state of the anti-fouling microphone chip 100, the difference between the pore size of the anti-fouling mesh 150 and the minimum distance between the diaphragm 120 and the anti-fouling mesh 150 is not less than 0.2 micrometers and not more than 1 micrometer.

The inventors of the present application consider that the antifouling microphone chip 100 provided by the present application requires the formation of the first air gap 100a between the diaphragm 120 and the antifouling net 150. For this reason, the present application provides one possible implementation manner for the anti-fouling microphone chip 100 as follows:

as shown in fig. 1, a diaphragm 120 of the embodiment of the present application includes a pedestal portion 121 and a vibrating portion 122 connected to each other.

The foundation pile part 121 is located on the side of the anti-fouling net 150 away from the substrate 110.

The vibrating portion 122 is a convex structure approaching to the back plate 130, and one side of the vibrating portion 122 facing to the anti-fouling net 150 encloses at least part of the first air gap 100a.

In this embodiment, the stub portion 121 of the diaphragm 120 may be stacked on a side of the anti-fouling mesh 150 away from the substrate 110 through a semiconductor film process, and the vibration portion 122 is a convex structure approaching to the back plate 130, which is beneficial to isolate a space between the back plate 130 and the anti-fouling mesh 150 into two subspaces, i.e., a side of the vibration portion 122 facing the anti-fouling mesh 150 is enclosed to form at least a portion of the first air gap 100a, and a side of the vibration portion 122 facing the back plate 130 is beneficial to form the second air gap 100b.

In one example, the vibrating portion 122 is a dome-shaped structure, the top of which is convex toward the back plate 130, and the bottom opening periphery of which is continuous with the foundation pile portion 121.

In one example, the protruding structure of the vibrating portion 122 near the back plate 130 may be specifically manufactured by the following processes: a sacrificial structure is manufactured on the side of the anti-fouling net 150 away from the substrate 110, the size and the position of the sacrificial structure correspond to the vibration part 122 to be prepared, then a polysilicon structure is manufactured on the side of the anti-fouling net 150 away from the substrate 110 and the sacrificial structure, then the sacrificial structure is eliminated, and the required diaphragm 120 can be obtained, namely, the polysilicon structure part on the side of the anti-fouling net 150 away from the substrate 110 forms the foundation pile part 121 of the diaphragm 120, and the polysilicon structure part in situ on the surface of the sacrificial structure forms the vibration part 122 of the diaphragm 120.

In one example, the pile portion 121 contacts a side of the anti-fouling mesh 150 away from the substrate 110, and the vibrating portion 122 encloses the anti-fouling mesh 150 to form a first air gap 100a.

In one example, the stub portions 121 may extend outward after the patterning process and form electrodes of the diaphragm 120 to facilitate acousto-electric conversion.

In some embodiments, an orthographic projection of the back cavity 110a on the first plane is located within an orthographic projection of the vibrating portion 122 on the first plane.

The embodiment is beneficial to aligning the position of the first air gap 100a with the position of the back cavity 110a, and is beneficial to forming a sound channel which is beneficial to external sound waves to smoothly enter between the first air gap 100a and the back cavity 110a, so that the energy loss of the sound waves is reduced, and the sound-electricity conversion quality is improved.

The inventor of the application considers that the middle and high-end TWS earphones generally need an active noise reduction function, and the quality of the active noise reduction performance is greatly related to the low-frequency response of a microphone. For a high sensitivity of the microphone, a sufficiently flexible diaphragm 120 may be used so that small sound pressure fluctuations are perceived. However, the diaphragm 120 is usually a complete thin film structure, any sound wave or other air pressure fluctuation will be completely applied to the diaphragm 120, the too soft diaphragm 120 cannot distinguish valid sound waves from other slowly changing air pressure fluctuations, the too soft diaphragm 120 will also be excited by slowly changing invalid air pressure fluctuations, and an invalid sensing audio signal is generated, i.e. noise is generated by mistake, resulting in insufficient noise reduction performance. For this reason, the present application provides one possible implementation manner for the anti-fouling microphone chip 100 as follows:

as shown in fig. 2, in the diaphragm 120 of the embodiment of the present application, the vibrating portion 122 has a pressure equalizing hole 120a communicating the first air gap 100a and the second air gap 100b.

In this embodiment, the vibrating diaphragm 120 is provided with the pressure equalizing hole 120a communicating the first air gap 100a and the second air gap 100b, which is beneficial to passing through of at least some other slowly changing air pressure fluctuations besides the effective sound waves, so as to achieve air pressure equalization of the spaces at two sides of the vibrating diaphragm 120, reduce or even avoid the generation of invalid sensing audio signals caused by the excitation of the slowly changing air pressure fluctuations of the vibrating diaphragm 120, improve the recognition accuracy of the antifouling microphone chip 100 on environmental sounds, and further, is beneficial to improving the noise reduction performance of a product adopting the antifouling microphone chip 100.

In some embodiments, the diameter of the pressure equalizing holes 120a is not less than 1 micron, and not greater than 20 microns.

The inventor of the present application considers that the position of the anti-fouling net 150 is preferably as far as possible to the front cavity 110a and the back cavity 110a, so as to reduce the obstruction to the sound wave, and if a corresponding limit structure is provided, the manufacturing process of accurate alignment of the anti-fouling net 150 can be simplified, and the product yield can be improved. For this reason, the present application provides one possible implementation manner for the antifouling microphone chip 100 as follows:

as shown in fig. 3, the substrate 110 of the embodiment of the present application includes a silicon-based layer 111 and an insulating substrate layer 112, which are stacked.

The silicon-based layer 111 and the insulating substrate layer 112 are respectively provided with a first through hole 111a and a second through hole 112a, and the first through hole 111a and the second through hole 112a are correspondingly communicated to form a back cavity 110a penetrating through two sides of the substrate 110.

As shown in fig. 4, the side of the insulating substrate layer 112 away from the substrate 110 has a limiting groove 112b.

The anti-fouling mesh 150 is in contact with the side of the insulating substrate layer 112 remote from the base plate 110 and in contact with at least part of the retaining groove 112b.

In this embodiment, the silicon substrate 111 serves as a main structural layer of the substrate 110, which provides a preparation basis for the whole preparation process of the anti-fouling microphone chip 100 and also provides a support for other film structures of the formed anti-fouling microphone chip 100.

The insulating substrate layer 112 can separate the anti-fouling net 150 prepared by a subsequent process from the silicon-based layer 111, so that the insulation between the anti-fouling net 150 and the silicon-based layer 111 is ensured.

The limiting groove 112b on the insulating substrate layer 112 is beneficial to limiting the anti-fouling net 150 prepared by the subsequent process, and helps the anti-fouling net 150 to be correctly aligned with the back cavity 110a formed on the insulating substrate layer 112 and the silicon substrate layer 111, so that the obstruction to sound waves is reduced.

The limiting groove 112b on the insulating substrate layer 112 is also beneficial to limiting the etching position of the anti-fouling net 150 in the preparation process of the anti-fouling net 150, namely beneficial to limiting the size of the prepared anti-fouling net 150.

The inventors of the present application contemplate that the backplate 130 needs to cooperate with the diaphragm 120 to generate the acousto-electric conversion signal. For this reason, the present application provides one possible implementation manner for the backplate 130 of the anti-fouling microphone chip 100 as follows:

as shown in fig. 5, the back plate 130 of the embodiment of the present application includes: a first insulating layer 131, a first conductive layer 132, and a second insulating layer 133 are provided in a stacked manner.

The first insulating layer 131, the first conductive layer 132, and the second insulating layer 133 have a first sound-transmitting hole 131a, a second sound-transmitting hole 132a, and a third sound-transmitting hole 133a, respectively.

The first, second, and third sound-transmitting holes 131a, 132a, and 133a are sequentially and correspondingly communicated to form the sound-transmitting hole 130a of the back plate 130 penetrating both sides thereof.

In this embodiment, the first conductive layer 132 is included between the first insulating layer 131 and the second insulating layer 133, so that the back plate 130 forms a sandwich structure, which is beneficial to reducing interference possibly suffered by the back plate 130 and improving the sensing accuracy of the anti-fouling microphone chip 100.

The sound-transmitting holes 130a of the backplate 130 can facilitate the elimination of a sacrificial layer during the preparation of the anti-fouling microphone chip 100, and the sacrificial layer can be removed to form a second air gap 100b between the diaphragm 120 and the backplate 130.

The inventors of the present application consider that the antifouling microphone chip 100 provided by the present application needs to form a second air gap 100b between the diaphragm 120 and the back plate 130. For this reason, the present application provides one possible implementation manner for the anti-fouling microphone chip 100 as follows:

as shown in fig. 1 to 3, the antifouling microphone chip 100 according to the embodiment of the present application further includes: a support structure 140 positioned between the substrate 110 and the backplate 130.

The diaphragm 120, the support structure 140, and the backplate 130 enclose a second air gap 100b.

In this embodiment, the supporting structure 140 may provide support for the back plate 130, and enable a sufficient space between the back plate 130 and the anti-fouling mesh 150 to be separated by the diaphragm 120 to form the first air gap 100a and the second air gap 100b.

In some embodiments, as shown in fig. 6, the support structure 140 includes: sacrificial material pegs 141 and isolation layer 142. The isolation layer 142 covers the surface of the sacrificial material piles 141.

In the embodiment, the sacrificial material foundation pile 141 is a main part of the supporting structure 140, and the sacrificial material can be used to share the material with the sacrificial layer filled between the diaphragm 120 and the back plate 130 in the process of manufacturing the microphone chip, so as to combine the processes, which is beneficial to simplifying the manufacturing process of the whole anti-fouling microphone chip 100 and reducing the cost.

The isolation layer 142 covering the surface of the sacrificial material stub 141 may protect a portion of the sacrificial material for supporting the back plate 130 from erosion during releasing the sacrificial material between the diaphragm 120 and the anti-fouling mesh 150, the sacrificial material between the diaphragm 120 and the back plate 130, and obtaining the first air gap 100a and the second air gap 100b, so as to obtain the support structure 140.

In some embodiments, as shown in fig. 7, the isolation layer 142 includes a third insulation layer 1421, a second conductive layer 1422, and a fourth insulation layer 1423, which are sequentially stacked. The side of the third insulating layer 1421 away from the second conductive layer 1422 contacts the surface of the sacrificial material stub 141.

In this embodiment, the isolation layer 142 includes a third insulation layer 1421, a second conductive layer 1422, and a fourth insulation layer 1423 stacked in sequence to form a sandwich structure, which is beneficial to protecting the sacrificial material stub 141 and preventing a portion of the sacrificial material used for supporting the back plate 130 from being corroded.

To further simplify the process and save materials, the layers of the isolation layer 142 may be combined with the layers of the back plate 130, specifically: the third insulating layer 1421 in the isolation layer 142 may share a process with the first insulating layer 131 in the back plate 130, the second conductive layer 1422 in the isolation layer 142 may share a process with the first conductive layer 132 in the back plate 130, and the fourth insulating layer 1423 in the isolation layer 142 may share a process with the second insulating layer 133 in the back plate 130.

Based on the same inventive concept, the embodiment of the application provides a sound collection device, which comprises: any of the anti-fouling microphone chips 100 as provided in the previous embodiments.

In this embodiment, the sound collection device may be an acoustic-to-electrical conversion product such as a mobile phone, a TWS (True Wireless Stereo) headset, or the like. Since each sound collection device employs the antifouling microphone chip 100 provided by the foregoing embodiments, the principle and technical effects thereof refer to the foregoing embodiments, and are not described herein again.

By applying the embodiment of the application, at least the following beneficial effects can be realized:

1. the anti-fouling net 150 is additionally arranged in the back cavity 110a of the microphone chip, so that external dirt such as dust, water and oil can be effectively prevented from entering the internal environment of the microphone chip, the possible contact between important electroacoustic structures such as the vibrating diaphragm 120 and the back plate 130 in the microphone chip and the external dirt can be effectively prevented, the probability that the electroacoustic structures in the microphone chip are corroded or damaged is effectively reduced, the acoustoelectric conversion quality of the microphone chip is improved, and the service life of the microphone chip is prolonged.

2. The sound wave can normally pass through the anti-fouling net 150, that is, the external sound wave can sequentially pass through the back cavity 110a of the anti-fouling microphone chip 100, the anti-fouling net 150, the first air gap 100a between the anti-fouling net 150 and the vibrating diaphragm 120 and then reach the vibrating diaphragm 120, so that the vibrating diaphragm 120 is bent and deformed under the action of the sound wave, a second air gap 100b between the vibrating diaphragm 120 and the back plate 130 is caused to change, further, the capacitance between the vibrating diaphragm 120 and the back plate 130 is changed, and the sound wave is converted into an electric signal. The first air gap 100a and the second air gap 100b provide a deformation space for the diaphragm 120.

3. The anti-fouling net 150 adopts micropores with pore diameters not larger than 6 microns, which is beneficial to prevent solid pollutants such as dust with particle diameters larger than 6 microns from entering the first air gap 100a, and the micropores can also form a barrier for liquid pollutants with certain pressure by utilizing the surface tension of the liquid.

4. The anti-fouling net 150 adopts micropores with a pore depth of not less than 1 micron and not more than 3.5 microns, and can utilize capillary effect to enhance the blocking effect on the formation of liquid pollutants.

5. Under the non-operating condition, the minimum distance between vibrating diaphragm 120 and dirt prevention net 150 is not more than the aperture of dirt prevention net 150, can be so that dirt prevention microphone chip 100 under operating condition, vibrating diaphragm 120 receives the effect of sound wave and takes place crooked deformation back, the thickness size of first air gap 100a can be equivalent to or slightly bigger than the aperture of dirt prevention net 150, be favorable to when some solid-state pollutants that the particle diameter is less than dirt prevention net 150 aperture happily pass through dirt prevention net 150 and reach first air gap 100a, also can not influence the normal deformation of vibrating diaphragm 120, guarantee the acoustoelectric conversion quality of microphone chip promptly.

6. The stub portion 121 of the diaphragm 120 may be stacked on a side of the anti-fouling mesh 150 away from the substrate 110 through a semiconductor film process, and the vibration portion 122 is a convex structure approaching to the back plate 130, which is beneficial to isolating a space between the back plate 130 and the anti-fouling mesh 150 into two subspaces, i.e., one side of the vibration portion 122 facing the anti-fouling mesh 150 encloses to form at least a part of the first air gap 100a, and one side of the vibration portion 122 facing the back plate 130 is beneficial to forming the second air gap 100b.

7. The orthographic projection of the back cavity 110a on the first plane is located within the orthographic projection of the vibration part 122 on the first plane, so that the position of the first air gap 100a is aligned with the position of the back cavity 110a, a sound channel which is beneficial for external sound waves to smoothly enter is formed between the first air gap 100a and the back cavity 110a, the energy loss of the sound waves is reduced, and the sound-electricity conversion quality is improved.

8. The pressure equalizing hole 120a communicating the first air gap 100a and the second air gap 100b is designed on the diaphragm 120, so that at least part of other slowly-changing air pressure fluctuation except for effective sound waves can pass through the pressure equalizing hole, the air pressure balance of the spaces at two sides of the diaphragm 120 is realized, the generation of invalid sensing audio signals caused by the excitation of the slowly-changing air pressure fluctuation of the diaphragm 120 is reduced or even avoided, the recognition precision of the antifouling microphone chip 100 on environmental sounds is improved, and the noise reduction performance of a product adopting the antifouling microphone chip 100 is improved.

9. The limiting groove 112b on the insulating substrate layer 112 is beneficial to limiting the anti-fouling net 150 prepared by the subsequent process, and helps the anti-fouling net 150 to be aligned with the back cavity 110a formed on the insulating substrate layer 112 and the silicon substrate layer 111 correctly, so that the obstruction to sound waves is reduced; it is also advantageous to define the etching position of the anti-fouling net 150 in the process of manufacturing the anti-fouling net 150, i.e., to define the size of the manufactured anti-fouling net 150.

It will be appreciated by those skilled in the art that in the description of the present application, it is to be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientations and positional relationships illustrated in the figures, which are used for convenience in describing the present application and to simplify description, and are not intended to indicate or imply that the device or component being referred to must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the present application.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless otherwise specified.

In the description of the present application, 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, a removable connection, or an integral connection; 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 application can be understood in a specific case by those of ordinary skill in the art.

The particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing is only a partial embodiment of the present application, and it should be noted that, for those skilled in the art, several modifications and decorations can be made without departing from the principle of the present application, and these modifications and decorations should also be regarded as the protection scope of the present application.

Claims (10)

1. An antifouling microphone chip is characterized by comprising a substrate, an antifouling net, a vibrating diaphragm and a back plate which are sequentially stacked;

the substrate is provided with a back cavity penetrating through two sides of the substrate, the orthographic projection of the back cavity on a first plane is positioned within the orthographic projection of the antifouling net on the first plane, and the first plane is the plane where the substrate is positioned;

a first air gap is arranged between the antifouling net and the diaphragm;

a second air gap is formed between the diaphragm and the back plate.

2. The anti-fouling microphone chip of claim 1, wherein the pore size of the anti-fouling mesh is no greater than 6 microns;

and/or, the anti-fouling mesh has a pore depth of not less than 1 micron and not more than 3.5 microns.

3. The anti-fouling microphone chip according to claim 1 or 2, wherein in a non-operating state, a minimum distance between the diaphragm and the anti-fouling mesh is not greater than an aperture of the anti-fouling mesh.

4. The antifouling microphone chip of claim 3, wherein the pore size of the antifouling net differs from the minimum distance between the diaphragm and the antifouling net by not less than 0.2 micrometers and not more than 1 micrometer.

5. The antifouling microphone chip of claim 1, wherein the diaphragm comprises a pedestal portion and a vibrating portion connected to each other;

the foundation pile part is positioned on one side of the antifouling net far away from the substrate;

the vibration part is a protruding structure close to the back plate, and one side of the vibration part facing the antifouling net is enclosed to form at least part of the first air gap.

6. The anti-fouling microphone chip of claim 5, wherein an orthographic projection of the back cavity on a first plane is located inward of an orthographic projection of the vibrating portion on the first plane.

7. The antifouling microphone chip of claim 5 or 6, wherein the vibrating portion has a pressure equalizing hole communicating the first air gap and the second air gap.

8. The anti-fouling microphone chip of claim 1, wherein the substrate comprises a laminated silicon-based layer and an insulating substrate layer;

the silicon substrate layer and the insulating substrate layer are respectively provided with a first through hole and a second through hole, and the first through hole and the second through hole are correspondingly communicated to form a back cavity of the substrate, wherein the back cavity penetrates through two sides of the substrate;

a limiting groove is formed in one side, away from the base plate, of the insulating substrate layer;

the antifouling net is in contact with one side, far away from the base plate, of the insulating substrate layer and is in contact with at least part of the limiting groove.

9. The anti-fouling microphone chip of claim 1, further comprising: a support structure located between the substrate and the backplate;

the diaphragm, the support structure and the back plate are enclosed to form the second air gap.

10. A sound collection device, comprising: the anti-fouling microphone chip of any one of claims 1-9.

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