CN210579224U

CN210579224U - Silicon microphone

Info

Publication number: CN210579224U
Application number: CN201921919944.3U
Authority: CN
Inventors: 张永强; 李刚; 其他发明人请求不公开姓名
Original assignee: Memsensing Microsystems Suzhou China Co Ltd
Current assignee: Memsensing Microsystems Suzhou China Co Ltd
Priority date: 2019-11-08
Filing date: 2019-11-08
Publication date: 2020-05-19
Anticipated expiration: 2029-11-08

Abstract

The utility model provides a silicon microphone, it utilizes the baffle will hold the chamber separation and be first chamber and second chamber, and will through the passageway the back chamber and second chamber or first chamber intercommunication of MEMS sensor have enlarged the volume of the back chamber of MEMS sensor, and the air volume increase of back chamber promptly, the sound wave that gets into from the sound hole promotes MEMS sensor's vibrating diaphragm motion more easily to improve silicon microphone's sensitivity and SNR, can also improve silicon microphone's frequency response performance simultaneously.

Description

Silicon microphone

Technical Field

The utility model relates to a micro-electromechanical system (MEMS) technical field especially relates to a silicon microphone.

Background

The MEMS (Micro-Electro-Mechanical System) technology is a high and new technology developed at a high speed in recent years, and it adopts an advanced semiconductor manufacturing process to implement the batch manufacturing of devices such as sensors and drivers, and compared with the corresponding conventional devices, the MEMS device has very obvious advantages in terms of volume, power consumption, weight and price. Major examples of applications of MEMS devices on the market include pressure sensors, accelerometers, and silicon microphones.

Silicon microphones, also known as MEMS microphones, are microphones fabricated based on MEMS technology. The MEMS microphone is composed of an MEMS sensor, an ASIC amplifier, an acoustic cavity and a circuit board with an RF suppression circuit. The MEMS sensor chip is a micro capacitor formed by a silicon diaphragm and a silicon back plate, and can convert sound pressure change into capacitance change, and then the capacitance change is reduced by an ASIC chip and is converted into an electric signal, so that the sound-electricity conversion is realized.

The silicon diaphragm divides the sound cavity of the silicon microphone into two parts, the area between the sound inlet hole and the silicon diaphragm is a front chamber, and the rest part of the sound cavity is a rear chamber. The air volume of the rear chamber of the existing silicon microphone is small, the difficulty of pushing a silicon diaphragm to move is increased, the sensitivity of an MEMS sensor is reduced, the signal-to-noise ratio of the silicon microphone is reduced, the air volume of the front chamber is large, the resonant frequency is reduced, and the frequency response performance of the silicon microphone is influenced.

Therefore, how to increase the volume of the back chamber of the MEMS sensor of the silicon microphone and improve the sensitivity, the signal-to-noise ratio and the frequency response performance of the silicon microphone becomes a technical problem to be solved urgently.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that a silicon microphone is provided, its volume that can increase the back chamber of MEMS sensor improves sensitivity, signal-to-noise ratio and the frequency response performance of silicon microphone.

In order to solve the above problem, the present invention provides a silicon microphone, which includes: a sound inlet hole; a housing; the substrate and the shell form an accommodating cavity, a channel is arranged in the substrate, the channel is provided with a first opening and a second opening, and the first opening and the second opening are positioned on the upper surface of the substrate; the partition plate is arranged in the accommodating cavity, two ends of the partition plate are respectively abutted against the upper surfaces of the shell and the substrate, the partition plate divides the accommodating cavity into a first cavity and a second cavity, the sound inlet hole is communicated with the first cavity or the second cavity, the first opening corresponds to the first cavity, and the second opening corresponds to the second cavity; and the acoustic assembly comprises a MEMS sensor, the MEMS sensor is arranged on the upper surface of the substrate, the MEMS sensor covers the first opening or the second opening, a rear chamber of the MEMS sensor is communicated with the second cavity or the first cavity through the channel, and the second cavity or the first cavity is used as an expanded rear chamber of the MEMS sensor.

Further, the baffle is the bar baffle, and it will hold the chamber and separate for parallel first chamber and the second chamber of arranging.

Further, the baffle is the annular baffle, and it will hold the chamber and divide into first chamber and the second chamber of arranging inside and outside.

Further, the second cavity surrounds the first cavity.

Further, the first cavity surrounds the second cavity.

Further, the sound inlet hole is formed in the shell, or the sound inlet hole is formed in the substrate, or the sound inlet hole is formed in the connecting position of the shell and the substrate.

Further, the sound inlet hole and the MEMS sensor are arranged in a staggered mode.

Further, the acoustic assembly further comprises an electrical chip, and the MEMS sensor is electrically connected to the electrical chip.

Further, the separator is a metal separator or a ceramic separator.

Further, the partition board and the substrate or the shell are hermetically connected by adopting metal solder or adhesive.

The utility model has the advantages of, utilize the baffle will it separates for first chamber and second chamber to hold the chamber, and will through the passageway the back chamber and second chamber or the first chamber intercommunication of MEMS sensor have enlarged the volume of the back chamber of MEMS sensor, and the air volume increase of back chamber promptly promotes MEMS sensor's vibrating diaphragm motion more easily from the sound wave that advances the sound hole entering to improve silicon microphone's sensitivity and SNR, can also improve silicon microphone's frequency response performance simultaneously.

Drawings

Fig. 1 is a schematic top view of a silicon microphone according to a first embodiment of the present invention;

3 FIG. 3 2 3 is 3 a 3 schematic 3 sectional 3 view 3 taken 3 along 3 line 3 A 3- 3 A 3 of 3 FIG. 3 1 3; 3

Figure 3 is a schematic cross-sectional view of a second embodiment of the silicon microphone of the present invention;

figure 4 is a schematic top view of a third embodiment of the silicon microphone of the present invention;

3 FIG. 3 5 3 is 3 a 3 schematic 3 sectional 3 view 3 taken 3 along 3 line 3 A 3- 3 A 3 of 3 FIG. 3 4 3; 3

Figure 6 is a schematic top view of a fourth embodiment of the silicon microphone of the present invention;

3 fig. 3 7 3 is 3 a 3 schematic 3 sectional 3 view 3 taken 3 along 3 line 3 a 3- 3 a 3 in 3 fig. 3 6 3. 3

Detailed Description

The following describes in detail a silicon microphone according to the present invention with reference to the accompanying drawings.

3 fig. 3 1 3 is 3 a 3 schematic 3 top 3 view 3 of 3 a 3 silicon 3 microphone 3 according 3 to 3 a 3 first 3 embodiment 3 of 3 the 3 present 3

invention

3, 3 and 3 fig. 3 2 3 is 3 a 3 schematic 3 cross 3- 3 sectional 3 view 3 taken 3 along 3 line 3 a 3- 3 a 3 of 3 fig. 3 1 3, 3 in 3 which 3 the 3 top 3 of 3 the 3 housing 3 1 3 is 3 removed 3 in 3 fig. 3 1 3 for 3 clarity 3 of 3 the 3 internal 3 structure 3 of 3 the 3 silicon 3 microphone 3. 3 Referring to fig. 1 and 2, the silicon microphone includes a housing 1, a substrate 2, a spacer 3, an acoustic element 4 and a sound inlet 5.

In the present embodiment, the sound inlet hole 5 is provided in the housing 1. The sound inlet hole 5 penetrates through the shell 1, namely the sound inlet hole 5 is a through hole. External sound air flows through the sound inlet hole 5 into the interior of the silicon microphone.

The substrate 2 and the housing 1 form a receiving cavity 100. In this embodiment, the substrate 2 has a flat configuration, the housing 1 has a concave configuration, the housing 1 is fastened to the substrate 2 to form the accommodating cavity 100, and an edge of the housing 1 is physically and hermetically connected to the substrate 2, for example, by using a metal solder or an adhesive. Fig. 3 is a schematic cross-sectional view of a second embodiment of the silicon microphone of the present invention, please refer to fig. 3, in the second embodiment of the present invention, the substrate 2 is a concave configuration, the housing 1 is a cover plate, and the housing 1 covers the substrate 2 to form the accommodating cavity 100.

Referring to fig. 1 and fig. 2, a channel 20 is disposed in the substrate 2, and the channel 20 has a first opening 20A and a second opening 20B. The first opening 20A and the second opening 20B are located on the upper surface of the substrate 2, the main body of the channel 20 is located in the substrate 2, and the airflow in the accommodating chamber 100 can flow through the channel 20 through the first opening 20A and the second opening 20B.

The partition plate 3 is disposed in the accommodating chamber 100, two ends of the partition plate 3 are respectively abutted to the upper surfaces of the housing 1 and the substrate 2, and the accommodating chamber 100 is divided into a first chamber 101 and a second chamber 102 by the partition plate 3.

In this embodiment, the partition 3 is a strip-shaped partition, two end surfaces of which respectively abut against the upper surfaces of the housing 1 and the substrate 2, and two side walls of which respectively abut against the side walls of the housing 1, so as to divide the accommodating cavity 100 into a first cavity 101 and a second cavity 102 which are arranged in parallel. The separator 3 is not limited to a rectangular strip separator, but may have strip separators of other shapes, for example, a wavy separator.

Further, the partition board 3 is a metal partition board or a ceramic partition board to play a role of shielding.

Further, the partition board 3 and the substrate 2 or the housing 1 are welded by using metal solder; or an adhesive is used for sealing connection, so that the first cavity 101 is not communicated with the second cavity 102.

The sound inlet hole 5 communicates with the first chamber 101. The sound inlet hole 5 is arranged corresponding to the first cavity 101. In the present embodiment, the sound inlet 5 is disposed at the top of the housing 1 corresponding to the first chamber 101. In other specific embodiments of the present invention, the sound inlet hole 5 may also be disposed on the side wall of the housing corresponding to the first cavity 101, or the sound inlet hole 5 is disposed on the substrate 2, or the sound inlet hole 5 is disposed at the connection position of the substrate 2 and the housing 1.

The first opening 20A corresponds to the first cavity 101 and the second opening 20B corresponds to the second cavity 102. That is, the first opening 20A is located on the upper surface of the substrate 2 corresponding to the first cavity 101, and the second opening 20B is located on the upper surface of the substrate 2 corresponding to the second cavity 102.

The acoustic assembly 4 comprises a MEMS sensor 40. The MEMS sensor 40 is disposed on the upper surface of the substrate 2 and located in the first cavity 101. The MEMS sensor 40 covers the first opening 20A, and a rear chamber of the MEMS sensor 40 corresponds to the first opening 20A.

The first cavity 101 serves as a front chamber of the MEMS sensor 40, and external sound airflow enters the first cavity 101 through the sound inlet hole 5 to push the MEMS sensor 40 to vibrate. The back chamber of the MEMS sensor 40 communicates with the second cavity 102 through the first opening 20A, the channel 20 and the second opening 20B, and then the second cavity 102 serves as an extended back chamber of the MEMS sensor 40, which together with the back chamber of the MEMS sensor 40 itself serves as the back chamber of the MEMS sensor 40. The utility model discloses increased the air volume of MEMS sensor 40's rear chamber promotes MEMS sensor 40's vibrating diaphragm motion more easily from the sound wave that advances the 5 entering of sound hole to improve the sensitivity and the SNR of silicon microphone, can also improve the frequency response performance of silicon microphone simultaneously.

Further, the acoustic assembly 4 further includes an electrical chip 41, the MEMS sensor 40 is electrically connected to the electrical chip 41, and the electrical chip 41 is electrically connected to an external pad (not shown in the drawings) through the substrate 2. The electrical chip 41 includes, but is not limited to, an Application Specific Integrated Circuit (ASIC) chip. The MEMS sensor 40 is encapsulated with the electrical chip 41 within the first cavity 101. The MEMS sensor 40 converts the acoustic wave into a capacitance change, and the electrical chip 41 detects the capacitance change and converts it into an electrical signal to be output to an external pad.

Further, in another embodiment of the present invention, the sound inlet hole 5 and the MEMS sensor 40 are disposed in a staggered manner, that is, the sound inlet hole 5 and the MEMS sensor 40 are disposed in different cavities, for example, the sound inlet hole 5 is communicated with the first cavity 101, the MEMS sensor 40 is disposed in the second cavity 102, or the sound inlet hole 5 is communicated with the second cavity 102, and the MEMS sensor 40 is disposed in the first cavity 101. The staggered arrangement has the advantages that adverse effects of excessive sound pressure on the reliability of the MEMS sensor 40 can be avoided, and particles in the environment can be prevented from contaminating the MEMS sensor 40 and affecting the acoustic performance of the MEMS sensor 40.

In the first embodiment of the present invention, the partition plate 3 is a bar-shaped partition plate, and in the third embodiment of the present invention, the partition plate 3 is an annular partition plate. 3 fig. 3 4 3 is 3 a 3 schematic 3 top 3 view 3 of 3 a 3 silicon 3 microphone 3 according 3 to 3 a 3 third 3 embodiment 3 of 3 the 3 present 3

invention

3, 3 and 3 fig. 3 5 3 is 3 a 3 schematic 3 cross 3- 3 sectional 3 view 3 taken 3 along 3 line 3 a 3- 3 a 3 of 3 fig. 3 4 3, 3 in 3 which 3 the 3 top 3 of 3 the 3 housing 3 1 3 is 3 removed 3 in 3 fig. 3 4 3 for 3 clarity 3 of 3 showing 3 the 3 internal 3 structure 3 of 3 the 3 silicon 3 microphone 3. 3 Referring to fig. 4 and 5, in the third embodiment, the partition plate 3 is an annular partition plate, and divides the accommodating cavity into a first cavity 101 and a second cavity 102 arranged inside and outside. The second chamber 102 surrounds the first chamber 101, i.e. the first chamber 101 is an inner chamber and the second chamber 102 is an outer chamber.

The sound inlet hole 5 is arranged at the top of the housing 1 corresponding to the first cavity 101, and the MEMS sensor 40 is arranged in the first cavity 101. The first cavity 101 serves as a front chamber of the MEMS sensor 40, and the rear chamber of the MEMS sensor 40 communicates with the second cavity 102 through the first opening 20A, the channel 20, and the second opening 20B, so that the second cavity 102 serves as an extended rear chamber of the MEMS sensor 40, which serves as a rear chamber of the MEMS sensor 40 together with a rear chamber of the MEMS sensor 40 itself. The external sound airflow enters the first cavity 101 through the sound inlet hole 5 to push the MEMS sensor 40 to vibrate. The air volume of the rear chamber of the MEMS sensor 40 is increased, and the sound wave entering from the sound inlet hole 5 more easily pushes the diaphragm of the MEMS sensor 40 to move, thereby improving the sensitivity and the signal-to-noise ratio of the silicon microphone, and also improving the frequency response performance of the silicon microphone.

The utility model discloses still provide one the fourth embodiment of silicon microphone. 3 fig. 3 6 3 is 3 a 3 schematic 3 top 3 view 3 of 3 a 3 silicon 3 microphone 3 according 3 to 3 a 3 fourth 3 embodiment 3 of 3 the 3 present 3

invention

3, 3 and 3 fig. 3 7 3 is 3 a 3 schematic 3 cross 3- 3 sectional 3 view 3 taken 3 along 3 line 3 a 3- 3 a 3 of 3 fig. 3 6 3, 3 in 3 which 3 the 3 top 3 of 3 the 3 housing 3 1 3 is 3 removed 3 in 3 fig. 3 6 3 for 3 clarity 3 of 3 showing 3 the 3 internal 3 structure 3 of 3 the 3 silicon 3 microphone 3. 3 Referring to fig. 6 and 7, in the fourth embodiment, the partition plate 3 is an annular partition plate, and divides the accommodating cavity into a first cavity 101 and a second cavity 102 arranged inside and outside. The first chamber 101 surrounds the second chamber 102, i.e. the second chamber 102 is an inner chamber and the first chamber 101 is an outer chamber.

In the fourth embodiment, the sound inlet 5 is disposed on the top of the housing 1 corresponding to the first cavity 101, and the MEMS sensor 40 is disposed in the first cavity 101. Since the first cavity 101 is an outer cavity, in another embodiment of the present invention, the sound inlet hole 5 may also be disposed on the side wall of the housing 1 adjacent to the substrate 2.

The first cavity 101 serves as a front chamber of the MEMS sensor 40, and the rear chamber of the MEMS sensor 40 communicates with the second cavity 102 through the first opening 20A, the channel 20, and the second opening 20B, so that the second cavity 102 serves as an extended rear chamber of the MEMS sensor 40, which serves as a rear chamber of the MEMS sensor 40 together with a rear chamber of the MEMS sensor 40 itself.

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

Claims

1. A silicon microphone, comprising:

a sound inlet hole;

a housing;

the substrate and the shell form an accommodating cavity, a channel is arranged in the substrate, the channel is provided with a first opening and a second opening, and the first opening and the second opening are positioned on the upper surface of the substrate;

the partition plate is arranged in the accommodating cavity, two ends of the partition plate are respectively abutted against the upper surfaces of the shell and the substrate, the partition plate divides the accommodating cavity into a first cavity and a second cavity, the sound inlet hole is communicated with the first cavity or the second cavity, the first opening corresponds to the first cavity, and the second opening corresponds to the second cavity;

and the acoustic assembly comprises a MEMS sensor, the MEMS sensor is arranged on the upper surface of the substrate, the MEMS sensor covers the first opening or the second opening, a rear chamber of the MEMS sensor is communicated with the second cavity or the first cavity through the channel, and the second cavity or the first cavity is used as an expanded rear chamber of the MEMS sensor.

2. A silicon microphone as claimed in claim 1 wherein the diaphragm is a strip diaphragm dividing the holding chamber into a first chamber and a second chamber arranged in parallel.

3. A silicon microphone as claimed in claim 1 wherein the diaphragm is an annular diaphragm dividing the holding chamber into a first chamber and a second chamber arranged in and out.

4. A silicon microphone as claimed in claim 3 wherein the second cavity surrounds the first cavity.

5. A silicon microphone as claimed in claim 3 wherein the first cavity surrounds the second cavity.

6. The silicon microphone according to any one of claims 1 to 5, wherein the sound inlet hole is provided on the housing, or the sound inlet hole is provided on the substrate, or the sound inlet hole is provided at a connection of the housing and the substrate.

7. A silicon microphone as claimed in claim 1 wherein the sound inlet hole is offset from the MEMS sensor.

8. A silicon microphone as claimed in claim 1 wherein the acoustic assembly further comprises an electrical chip, the MEMS sensor being electrically connected to the electrical chip.

9. A silicon microphone as claimed in claim 1 wherein the diaphragm is a metal diaphragm or a ceramic diaphragm.

10. A silicon microphone as claimed in claim 1 wherein the diaphragm is hermetically connected to the substrate or the housing using a metallic solder or an adhesive.