CN211702390U

CN211702390U - MEMS microphone and electronic product

Info

Publication number: CN211702390U
Application number: CN202020401714.4U
Authority: CN
Inventors: 张瑞霞
Original assignee: Goertek Microelectronics Inc
Current assignee: Goertek Microelectronics Inc
Priority date: 2020-03-25
Filing date: 2020-03-25
Publication date: 2020-10-16
Anticipated expiration: 2030-03-25

Abstract

The utility model relates to a MEMS microphone and electronic product, including base plate, backup pad, water proof membrane and MEMS chip, be formed with heavy groove on the first surface of base plate, set up the main sound hole that link up on the base plate, main sound hole communicates to on the bottom surface of heavy groove; the supporting plate is arranged on the base plate, covers the sinking groove and is provided with a through infrasound hole; the waterproof membrane is arranged in the sinking groove, the waterproof membrane separates the main sound hole from the infrasound hole, and the main sound hole and the infrasound hole are respectively positioned at two sides of the waterproof membrane; the MEMS chip is arranged on the supporting plate or the substrate. The utility model provides a MEMS microphone, in foreign matters such as dust, liquid in the waterproof membrane can prevent the outside environment got into MEMS microphone, improved MEMS microphone's reliability.

Description

MEMS microphone and electronic product

Technical Field

The utility model relates to a micro-electro-mechanical system field, concretely relates to MEMS microphone and electronic product.

Background

A Micro-Electro-Mechanical System (MEMS) microphone is an acoustoelectric transducer manufactured based on the MEMS technology, has the characteristics of small volume, good frequency response, low noise and the like, and is one of essential devices of a mobile terminal. Generally, a MEMS microphone product includes a MEMS chip based on capacitance detection and an Application Specific Integrated Circuit (ASIC) chip, where the capacitance of the MEMS chip changes correspondingly with the change of an incoming sound, and the ASIC chip processes and outputs a changed capacitance signal to pick up the sound.

In recent years, the related technologies of electronic products have been developed rapidly, and the performance requirements of electronic products are higher and higher, so as to meet the application requirements and reliability requirements of electronic products in different environments. The current MEMS microphone needs to directly receive external sound, so the MEMS chip is directly connected to the external environment through the microphone sound hole. This design results in a strong tendency for dust, liquid, etc. in the outside environment to enter the MEMS microphone from the microphone sound hole, thereby affecting the acoustic performance of the MEMS microphone. MEMS microphones suffer from water ingress failure and have limited reliability.

SUMMERY OF THE UTILITY MODEL

It is an object of the present invention to provide an improved MEMS microphone and electronic product.

According to an aspect of the present invention, there is provided a MEMS microphone, including:

the substrate is provided with a through main sound hole, and the main sound hole is communicated to the bottom surface of the sinking groove;

the supporting plate is arranged on the base plate, covers the sinking groove and is provided with a through infrasound hole;

the waterproof membrane is arranged in the sinking groove and separates the main sound hole from the infrasound hole, and the main sound hole and the infrasound hole are respectively positioned on two sides of the waterproof membrane;

a MEMS chip disposed on the support plate or the substrate.

Optionally, the MEMS chip further includes a package cover, the package cover is disposed on the first surface of the substrate, the package cover and the first surface form a back cavity, and the MEMS chip and the supporting plate are located in the back cavity.

Optionally, the MEMS chip is disposed on the supporting plate, and an inner cavity of the MEMS chip is communicated with the infrasound hole.

Optionally, the support plate further comprises an ASIC chip, and the ASIC chip is disposed on the support plate.

Optionally, the main acoustic hole is composed of a plurality of holes distributed on the substrate;

and/or the presence of a gas in the gas,

the secondary sound hole is composed of a plurality of holes distributed on the supporting plate.

Optionally, the edge of the waterproof membrane is fixed on the bottom surface of the sinking groove in an adhesion mode.

Optionally, a step is arranged on the top surface of the sinking groove, the supporting plate is fixedly combined with the step, and the surface of one side, far away from the sinking groove, of the supporting plate is flush with the first surface of the substrate.

Optionally, the support plate is fixed on the substrate by means of bonding or welding.

Optionally, the shape of the waterproofing membrane matches the shape of the sink.

Optionally, the depth of the sinking groove is less than or equal to one half of the thickness of the substrate.

Optionally, a first gap is formed between the waterproof membrane and the bottom surface of the sinking groove;

and/or the presence of a gas in the gas,

a second gap is formed between the waterproof membrane and the support plate.

According to the utility model discloses a second aspect provides an electronic product, include: a product body and the above-mentioned MEMS microphone, the MEMS microphone being disposed in the product body, the MEMS microphone being configured for receiving sound for conversion into a sound signal.

Technical scheme's beneficial effect lies in effectively preventing through the water proof membrane that foreign matters such as dust, liquid in the outside environment from getting into the MEMS microphone, improves the reliability of MEMS microphone.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments of the invention, which proceeds with reference to the accompanying drawings.

Drawings

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

Fig. 1 is a schematic structural diagram of a MEMS microphone according to an embodiment of the present invention;

fig. 2 is a reference diagram of a usage state of a MEMS microphone according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a MEMS microphone according to another embodiment of the present invention;

fig. 4 is a reference diagram of a usage state of a MEMS microphone according to another embodiment of the present invention.

In the figure: 1. a substrate; 101. sinking a groove; 102. a primary sound hole; 2. a support plate; 201. a secondary sound hole; 3. a water-resistant film; 4. an MEMS chip; 5. packaging the shell; 501. a back cavity; 6. an ASIC chip.

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: unless specifically stated otherwise, the relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

As shown in fig. 1 to 4, the present embodiment provides a MEMS microphone including a substrate 1, a support plate 2, a waterproof membrane 3, and a MEMS chip 4. A sink 101 is formed on the first surface of the substrate 1, and the sink 101 is recessed downward with respect to the first surface of the substrate 1 by a certain distance, thereby forming an accommodating space in the substrate 1; the substrate 1 is provided with a through main sound hole 102, and the main sound hole 102 is communicated with the bottom surface of the sink 101. As shown in fig. 1, the main sound hole 102 penetrates from the bottom surface of the sink 101 to the bottom surface of the substrate 1, and the main sound hole 102 communicates between the first surface and the bottom surface of the substrate 1 through the sink 101. In this embodiment, the primary sound hole 102 is located in the sink 101. In other embodiments, the main sound hole may have a curved extension in the substrate according to the actual sound transmission requirement, and also may have a technical feature that two ends of the main sound hole penetrate through the upper and lower sides of the substrate through the sinking grooves.

Specifically, the support plate 2 is disposed on the base plate 1. Alternatively, the support plate 2 is disposed on the first surface of the substrate 1, and the support plate 2 covers the sink 101, and the sink 101 is located below the support plate 2. The supporting plate 2 is provided with a through infrasound hole 201. And under the condition that the waterproof membrane is not arranged, the main sound hole is communicated with the secondary sound hole through the sinking groove. The waterproof membrane 3 is disposed in the sink 101, and the waterproof membrane 3 separates the main sound hole 102 and the secondary sound hole 201, and the main sound hole 102 and the secondary sound hole 201 are respectively located on both sides of the waterproof membrane 3. Through setting up the water proof membrane, receive the water proof membrane protection through the inside part of infrasound hole intercommunication in MEMS microphone, the foreign matter that gets into from main sound hole can be blocked by the water proof membrane, is difficult to get into the infrasound hole.

The MEMS chip 4 is arranged on the supporting plate 2 or the substrate 1, and the supporting plate 2 or the substrate 1 is used for supporting the MEMS chip 4.

Optionally, the MEMS chip 4 is disposed on the supporting plate 2, an inner cavity of the MEMS chip 4 is communicated with the infrasound hole 201, and the MEMS chip 4 senses sound pressure entering the inner cavity of the MEMS chip 4 from the infrasound hole 201 and converts the sound pressure into an electrical signal.

In this embodiment, the operating principle of the MEMS microphone is as follows: the sound sequentially passes through the main sound hole 102, the waterproof membrane 3 and the secondary sound hole 201, then enters the inner cavity of the MEMS chip 4, and the MEMS chip 4 senses the sound pressure and converts the sound pressure into an electrical signal.

The waterproof membrane 3 is used for preventing foreign matters such as dust and liquid in the external environment from entering the secondary sound hole 201 from the main sound hole 102, and further effectively preventing the foreign matters such as dust and liquid in the external environment from entering the inner cavity of the MEMS chip 4. This helps to keep the MEMS chip 4 having a clean and tidy cavity environment, thereby ensuring that the MEMS chip 4 can quickly and accurately sense the sound pressure and convert the sound pressure into an electrical signal. Meanwhile, when strong airflow enters from the main sound hole 102, the waterproof membrane 3 can intercept impact force brought to the MEMS chip 4 by the strong airflow, so that the stability that the MEMS chip 4 converts sound pressure into an electric signal is ensured, and the stability and reliability of the MEMS microphone in the using process are ensured.

The technical scheme of the utility model through set up heavy groove 101 on the base plate in order to hold waterproofing membrane 3. On one hand, the occupied space is small, and the influence on the overall appearance of the MEMS microphone is small. And, the waterproof membrane 3 is directly arranged in the sinking groove 101 of the substrate 1, and the processing technology is simple. On the other hand, the waterproof membrane 3 can be protected by the substrate 1, reducing the risk of damage. Particularly, the waterproof membrane 3 does not occupy the internal volume of the MEMS microphone additionally, and meets the requirement of the internal structure of the MEMS microphone to be compact. In practical application, the MEMS microphone can meet the size requirement of a product where the MEMS chip is located, and the MEMS microphone with good waterproof and dustproof performances is provided for the product.

The utility model discloses a waterproof membrane can keep apart main sound hole and infrasound hole completely through sealed fixed connection form, also can adopt unsealed fixed connection form, leaves the gap that supplies sound to pass, reduces the acoustic resistance.

The material of the waterproofing membrane itself can take at least two different forms. The first form is that the waterproof membrane has high density and good isolation and waterproof performance, and airflow is difficult to directly pass through. The waterproof membrane can adopt a sealed fixed connection mode, sound waves transmitted from the main sound hole generate pressure on the waterproof membrane, the waterproof membrane vibrates, and sound vibration is transmitted to the MEMS chip through the infrasound hole, so that sound transmission is realized. In the second form, the membrane is relatively low density and has some water-repellent properties while allowing air flow therethrough. The sound waves transmitted from the main sound hole can be directly transmitted to the secondary sound hole and the MEMS chip through the waterproof membrane, and the sound transmission is realized.

Optionally, the MEMS microphone further includes a package 5, the package 5 is disposed on the first surface of the substrate 1, the package 5 and the first surface form a back cavity 501, and the MEMS chip 4 and the support plate 2 are located in the back cavity 501. The package 5 not only can better protect the MEMS chip 4, but also facilitates the MEMS chip 4 to accurately sense the sound pressure in the closed back cavity 501 and convert the sound pressure into an electrical signal. The back cavity structure is designed for the MEMS microphone, so that the acoustic performance of the microphone can be effectively improved.

In a specific embodiment, as shown in fig. 3 and 4, the MEMS microphone further includes an ASIC chip 6, and the ASIC chip 6 is disposed on the support plate 2. The support plate 2 supports the ASIC chip 6. By placing the ASIC chip 6 on the support plate 2, which would otherwise leave room for carrying the ASIC chip or other devices, it can be used to form a sink. Thus, the area occupied by the sink 101 on the substrate 1 can be increased for accommodating the waterproof sound-transmitting membrane having a larger area. The larger the area of the waterproof membrane is, the weaker the obstruction effect of the waterproof membrane on the propagation process of sound vibration from the primary sound hole to the secondary sound hole is, so that sound can better penetrate through the waterproof membrane 3 and enter the inner cavity of the ASIC chip 6 from the secondary sound hole 201, and the sound loss is smaller. In addition, the waterproof membrane with a relatively large area can also comprehensively improve the acoustic performance of the MEMS microphone, so that the MEMS microphone is ensured to have a low distortion rate and a good acoustic effect. In an alternative embodiment, the waterproof membrane occupies a larger area in the substrate, and the membrane material thereof may be a material with better isolation performance. Thus, foreign substances are difficult to pass through the waterproof film. On the other hand, because the waterproof membrane has a large area, when the waterproof membrane receives sound vibration, the sensitivity of the vibration generated along with the waterproof membrane is high, the sound transmitted from the main sound hole can be better reduced, and then the vibration is transmitted to the MEMS chip. The distortion degree of the MEMS microphone is reduced, and meanwhile, the waterproof performance is guaranteed.

In the present embodiment, the MEMS chip 4 and the ASIC chip 6 are connected by a wire, and the ASIC chip 6 is connected to the substrate 1 by a wire. The capacitance of the MEMS chip changes correspondingly with the difference of the input sound signal, and then the ASIC chip processes the changed capacitance signal and outputs the processed capacitance signal to the substrate 1, thereby realizing the sound pickup.

Alternatively, the main acoustic hole 102 is composed of a plurality of holes distributed on the substrate 1, that is, the main acoustic hole may not be a single hole but be composed of a plurality of holes. The main sound hole refers to a hole structure provided on a substrate, penetrating the substrate so that sound is transmitted therethrough. In an alternative embodiment, the main sound hole may be formed by three through holes distributed side by side. The main sound hole is designed into a plurality of holes, so that external impurities can be blocked preliminarily and enter the sink groove 101 through the main sound hole 102, the effect of reducing air flow impact can be achieved, and the waterproof membrane is prevented from being damaged due to strong air flow impact.

Optionally, the secondary acoustic aperture 201 is made up of a plurality of holes distributed on the support plate 2, which helps to block impurities from entering the internal cavity of the MEMS chip 4. Meanwhile, sound can enter the inner cavity of the MEMS chip 4 through the main sound hole 102, the waterproof membrane 3, and the sub-sound hole 201 more smoothly and sequentially, so that the MEMS chip 4 converts the sound signal into an electrical signal.

Alternatively, the edge of the waterproof membrane 3 is adhesively fixed on the bottom surface of the sink 101, which improves the stability of fixing the waterproof membrane 3 on the substrate 1. The edge of the waterproof membrane is bonded and fixed in the sinking groove to achieve the effect of sealing connection, and the waterproof membrane is bonded and connected with the bottom surface of the sinking groove in an annular sealing mode, so that the main sound hole and the secondary sound hole are completely separated. The waterproof membrane can better play the effect of filtration, isolation.

Alternatively, the support plate 2 is fixed to the base plate 1 by bonding or soldering. This enables the support plate 2 to be firmly fixed to the base plate 1. In embodiments in which the support plate is fixed to the substrate by soldering, the support plate may be electrically connected to the substrate by soldering. Furthermore, a circuit can be formed in the support plate, and the MEMS chip can be electrically connected to the substrate through the support plate.

Optionally, a step is disposed on the top surface of the sinking groove 101, the supporting plate 2 is fixedly combined with the step, and a side surface of the supporting plate 2 away from the sinking groove 101 is flush with the first surface of the substrate 1. The step is spacing to the fixed position of backup pad 2, is convenient for fix backup pad 2 on base plate 1 fast. The surface of the supporting plate 2 on the side far away from the sink 101 is flush with the first surface of the substrate 1, which helps to increase the volume of the back cavity formed by the package housing 5 and the first surface.

Optionally, the shape of the waterproofing membrane 3 matches the shape of the sink 101. The shape of the waterproof membrane 3 is matched according to the shape of the sinking groove 101, so that the outer edge of the waterproof membrane 3 is conveniently fixed in the sinking groove 101, the waterproof membrane 3 can better separate the main sound hole 102 from the secondary sound hole 201, foreign matters are effectively prevented from entering the secondary sound hole from the main sound hole, the waterproof and dustproof effects of the MEMS microphone are improved, the area of the waterproof membrane 3 is greatly increased, the acoustic performance of the MEMS microphone is comprehensively improved, and the MEMS microphone is guaranteed to have lower distortion rate and better acoustic effect.

Optionally, the depth of the sink 101 is less than or equal to one-half of the thickness of the substrate 1. This makes the position department that the bottom surface of base plate 1 and heavy groove 101 corresponds have certain thickness to guaranteed that base plate 1 has sufficient intensity in the position department that the bottom surface of heavy groove 101 corresponds, also guaranteed simultaneously that the main sound hole has certain degree of depth, can prevent preliminarily that the great foreign matter of volume from getting into the heavy groove by main sound hole, improve MEMS microphone and prevent that the foreign matter from getting into its inside reliability.

As shown in fig. 1 and 3, a first gap is formed between the waterproof membrane 3 and the bottom surface of the sink 101, so that the waterproof membrane is bonded to the bottom surface of the sink in an annular sealing manner, and thus the waterproof membrane 3 can better block foreign matters, and the reliability of the MEMS microphone is improved.

Optionally, have the second clearance between waterproof membrane 3 and the backup pad 2, this waterproof membrane 3 of being convenient for can shake in the second clearance when receiving sound vibration, and the sensitivity that self produced the vibration thereupon is higher, and the sound that can be better still is spread into by main sound hole, and then gives the MEMS chip vibration transmission again. The distortion degree of the MEMS microphone is reduced, and meanwhile, the waterproof performance is guaranteed.

In addition, the present embodiment provides an electronic product including a product body and the above-described MEMS microphone, the MEMS microphone being provided in the product body, the MEMS microphone being configured to receive sound to be converted into a sound signal. The electronic product can effectively prevent dust and liquid foreign matters from entering the MEMS microphone, so that the reliability of the MEMS microphone is improved, and the electronic product has higher reliability and good acoustic performance.

Although certain specific embodiments of the present invention have been described in detail by way of example, it should be understood by those skilled in the art that the foregoing examples are for purposes of illustration only and are not intended to limit the scope of the invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A MEMS microphone, comprising:

a MEMS chip disposed on the support plate or the substrate.

2. The MEMS microphone of claim 1, further comprising a package cover disposed on the first surface of the substrate, the package cover and the first surface forming a back cavity, the MEMS chip and the support plate being located in the back cavity.

3. The MEMS microphone of claim 1, wherein the MEMS chip is disposed on the support plate, and an inner cavity of the MEMS chip is in communication with the infrasound hole.

4. The MEMS microphone of claim 1, further comprising an ASIC chip disposed on the support plate.

5. The MEMS microphone of claim 1, wherein the primary acoustic aperture is comprised of a plurality of holes distributed on the substrate;

and/or the presence of a gas in the gas,

6. The MEMS microphone of claim 1, wherein an edge of the waterproof membrane is adhesively fixed on a bottom surface of the sink.

7. The MEMS microphone of claim 1, wherein a step is disposed on a top surface of the sinking groove, the supporting plate is fixedly combined with the step, and a surface of the supporting plate, which is away from the sinking groove, is flush with the first surface of the substrate.

8. The MEMS microphone of claim 1, wherein the support plate is fixed to the substrate by bonding or soldering.

9. The MEMS microphone of any one of claims 1 to 8, wherein the waterproof membrane has a shape that matches a shape of the sink.

10. The MEMS microphone of any one of claims 1 to 8, wherein the depth of the sinker is less than or equal to one-half of the thickness of the substrate.

11. The MEMS microphone of any one of claims 1 to 8, wherein the waterproof membrane has a first gap with a bottom surface of the sink;

and/or the presence of a gas in the gas,

a second gap is formed between the waterproof membrane and the support plate.

12. An electronic product, comprising: a product body and a MEMS microphone according to any of claims 1-11, the MEMS microphone being disposed in the product body, the MEMS microphone being configured for receiving sound for conversion into a sound signal.