CN110482477A - Silicon microphone packaging structure and its packaging method - Google Patents

Abstract

A silicon microphone packaging structure and a packaging method thereof, the silicon microphone packaging structure comprising: a circuit board having opposite first and second surfaces; a first metal shell disposed on the first surface of the circuit board , forming a first cavity with the circuit board, the first metal shell has a first sound hole; the second metal shell is arranged on the first surface of the circuit board, and sleeved on the The outside of the first metal shell forms a second cavity with the first metal shell and the circuit board. The second metal shell has a second sound hole whose side wall is recessed toward the inside. The second The side wall of the sound hole is in sealing connection with the first metal shell, and the first sound hole communicates with the second sound hole; the microphone chip is arranged in the first cavity. The electromagnetic shielding capability of the silicon microphone packaging structure is improved.

Description

Silicon Microphone Packaging Structure and Packaging Method

technical field

The invention relates to the technical field of MEMS, in particular to a silicon microphone packaging structure and a packaging method thereof.

Background technique

A MEMS microphone usually includes a MEMS chip and an ASIC (Application Specific Integrated Circuit, functional integrated circuit) chip electrically connected thereto, wherein the MEMS chip includes a substrate, a diaphragm and a back pole fixed on the substrate, and the diaphragm and the back pole constitute a The capacitor is integrated on the silicon wafer. The sound enters the microphone through the sound hole and acts on the diaphragm of the MEMS chip. Through the vibration of the diaphragm, the distance between the diaphragm and the back electrode is changed, thereby converting the sound signal into an electrical signal.

Facing the complex electromagnetic environment and assembly process environment in electronic equipment, MEMS chips are required to have performances such as anti-electromagnetic environment and good heat insulation, which put forward higher requirements for chip packaging. In traditional packaging structures, metal shells are generally used to shield electromagnetic waves in the external environment. This type of packaging structure is relatively simple, and can only shield a small part of electromagnetic waves, and still more electromagnetic waves will penetrate the shell, affecting the normal operation of the chip in the package.

How to further improve the shielding ability of silicon microphones to electromagnetic waves, so as to improve the performance of silicon microphone packaging structures, is an urgent problem to be solved at present.

Contents of the invention

The technical problem to be solved by the present invention is to provide a silicon microphone packaging structure and a packaging method thereof, so as to improve the acoustic performance and anti-electromagnetic interference capability of the silicon microphone.

In order to solve the above problems, the present invention provides a silicon microphone packaging structure, comprising: a circuit board having opposite first and second surfaces; a first metal shell disposed on the first surface of the circuit board, A first cavity is formed between the circuit board and the first metal shell has a first sound hole; the second metal shell is arranged on the first surface of the circuit board and sleeved on the Outside the first metal shell, a second cavity is formed between the first metal shell and the circuit board, the second metal shell has a second sound hole whose side wall is recessed toward the inside, and the second sound hole is The side wall of the hole is in sealing connection with the first metal shell, and the first sound hole communicates with the second sound hole; the microphone chip is arranged in the first cavity.

Optionally, the first sound hole of the first metal shell has a side wall protruding outward, and the first sound hole passes through the second sound hole.

Optionally, the side wall of the second acoustic hole is sealed and connected to the first metal shell through a sealing material, and the sealing material includes silica gel, epoxy glue, conductive silver glue, solder paste, and high temperature resistant adhesive. at least one of the glues.

Optionally, it further includes: a channel located in the circuit board, one end of the channel is connected to the back cavity of the microphone chip, and the other end is connected to the second cavity.

Optionally, the first metal shell and/or the second metal shell are sealed and connected to the circuit board through a conductive material.

Optionally, a ground terminal is formed on the circuit board, and the first metal shell and/or the second metal shell are connected to the ground terminal through circuit wiring of the circuit board.

Optionally, conductive slots respectively corresponding to the first metal shell and/or the second metal shell are formed in the circuit board, and the first metal shell and/or the second metal shell are respectively inserted into the conductive slot to form an electrical connection with the conductive slot.

Optionally, the conductive slot is electrically connected to the ground terminal of the circuit board.

Optionally, the first sound hole and/or the second sound hole is covered with a dustproof film.

Optionally, the dustproof film is a conductive film.

In order to solve the above technical problems, the specific embodiment of the present invention also provides a silicon microphone packaging method, including: providing a circuit board with opposite first and second surfaces; fixing the microphone chip on the circuit board; providing a second A metal shell, the first metal shell is arranged on the first surface of the circuit board, and a first cavity is formed between the first metal shell and the circuit board, and the microphone chip is located in the first cavity, The first metal shell has a first sound hole; the first metal shell is provided, and the second metal shell is set outside the first metal shell and fixed on the first surface of the circuit board A second cavity is formed between the first metal shell and the circuit board, the second metal shell has a second sound hole with a side wall recessed toward the inside, the side wall of the second sound hole is in contact with the The first metal shell is sealed and connected, and the first sound hole communicates with the second sound hole.

Optionally, the first sound hole of the first metal shell has a side wall protruding outward, and the first sound hole passes through the second sound hole.

Optionally, the side wall of the second sound hole is sealed and connected to the first metal shell through a sealing material, and the sealing material includes silica gel, epoxy glue, conductive silver glue, solder paste and high temperature resistant glue at least one of the

Optionally, a channel is further formed in the circuit board, one end of the channel communicates with the back cavity of the microphone chip, and the other end of the channel communicates with the second cavity.

Optionally, the first metal shell and/or the second metal shell are sealed and connected to the circuit board through a conductive material.

Optionally, a ground terminal is formed on the circuit board, and the first metal shell and/or the second metal shell are connected to the ground terminal through circuit wiring of the circuit board.

Optionally, conductive slots respectively corresponding to the first metal shell and/or the second metal shell are formed in the circuit board; the first metal shell and/or the second metal shell respectively inserted into the conductive slots to form an electrical connection with the conductive slots.

Optionally, the conductive slot is electrically connected to the ground terminal of the circuit board.

Optionally, a dust-proof film covering the first sound hole and/or the second sound hole is formed.

Optionally, the dustproof film is a conductive film.

The silicon microphone packaging structure of the present invention is a top sound-intake structure, including a first metal shell and a second metal shell, and there is a gap between the shells on both sides, and the shielding ability to external electromagnetic waves is improved through the two-layer metal shell ; and the first metal shell and the second metal shell are provided with sound holes, which can avoid the problem of poor welding caused by gas expansion inside the cavity during the packaging process.

Further, a channel connected to the back cavity of the microphone chip is formed in the circuit board, which is conducive to increasing the effective volume of the back cavity of the silicon microphone and improving the acoustic performance of the packaging structure of the silicon microphone; the channel is also connected to the first metal shell The second cavity between the body and the second metal shell further expands the effective volume of the back cavity of the microphone chip, thereby improving the acoustic performance of the silicon microphone package structure.

Further, the first metal shell and/or the second metal shell may also be connected to the ground terminal of the circuit board, which is beneficial to improving the electromagnetic shielding effect and improving the electrostatic protection performance.

Description of drawings

Fig. 1 is a structural schematic diagram of a silicon microphone packaging structure according to a specific embodiment of the present invention;

Fig. 2 is a structural schematic diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention;

Fig. 3 is a structural schematic diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention;

Fig. 4 is a structural schematic diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention;

Fig. 5 is a structural schematic diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a silicon microphone package structure according to another specific embodiment of the present invention.

Detailed ways

The specific implementation of the silicon microphone packaging structure and packaging method provided by the present invention will be described in detail below in conjunction with the accompanying drawings.

Please refer to FIG. 1 , which is a schematic diagram of a microphone package structure according to a specific embodiment of the present invention.

In this specific implementation manner, the microphone packaging structure includes: a circuit board 100 , a first metal shell 110 , a second metal shell 120 , and a microphone chip 150 .

The circuit board 100 has a first surface and a second surface opposite to each other. Circuit wiring is formed in the circuit board 100 .

The first metal shell 110 is disposed on the first surface of the circuit board 100 and forms a first cavity 130 with the circuit board 100 . The second metal shell 120 is disposed on the first surface of the circuit board 100 , and sleeved outside the first metal shell 110 , between the first metal shell 110 and the circuit board 100 . A second cavity 140 is formed between them. The size of the second cavity 140 can be set according to the volume requirement of the packaging structure.

The first metal shell 110 and the second metal shell 120 can be made of the same or different metal materials, including metal materials such as copper base material, nickel base material and zinc base material.

The first metal shell 110 and the second metal shell 120 are sealed and fixed on the first surface of the circuit board 100 respectively. The sealing connection between the first metal shell 110 and the second metal shell 120 and the circuit board 100 can be realized by welding or glue.

The microphone chip 150 is disposed in the first cavity 130 . In this specific embodiment, the silicon microphone packaging structure further includes an ASIC chip 160, and the ASIC chip 160 is also arranged in the first cavity 130, and the ASIC chip 160 is electrically connected to the microphone chip 150 and the microphone chip 150 respectively. The circuit board 100. The microphone chip 150 includes a sound pressure sensing layer, and a back cavity 151 located on one side of the sound pressure sensing layer. The ASIC chip 160 can be electrically connected to the microphone chip 150 and the circuit board 100 respectively through wires, and is used to receive the induction signal of the microphone chip 150 , process it, and output it through the circuit board 100 . The microphone chip 150 and the ASIC chip 160 may be fixed on the surface of the circuit board 100 by insulating glue.

In other specific implementation manners, the ASIC chip can also be embedded inside the circuit board 100 and directly connected to the circuit wiring inside the circuit board 100 , and the microphone chip 150 is connected to the ASIC chip by soldering or wires.

The microphone chip 150 and the ASIC chip 160 are arranged in the first cavity 130 and are covered by the first metal shell 110 and the second metal shell 120, and the first metal shell 110 And the second metal shell 120 serves as an electromagnetic shielding layer, which is beneficial to shield the influence of external electromagnetic waves on the ASIC chip 160 and the microphone chip 150 .

The use of a double-layer metal shell can improve the shielding ability of electromagnetic waves, and in the specific embodiment of the present invention, there is a certain gap between the first metal shell 110 and the second metal shell 120, which can further improve the electromagnetic shielding effect, Play a double shielding effect.

The microphone packaging structure further includes: a channel 170 located in the circuit board 100 , and one end of the channel 170 is connected to the back cavity 151 of the microphone chip 150 .

In some specific implementations, the other end of the channel 170 may be located in the circuit board 100 and not communicated with the second cavity 140 . The channel 170 and the back cavity 151 increase the actual volume of the back cavity of the microphone chip 150, which is beneficial to improve the acoustic performance of the microphone package structure.

In this specific embodiment, the other end of the channel 170 is connected to the second cavity 140, and both the second cavity 140 and the channel 170 are connected to the back cavity 151, further increasing the size of the microphone chip. The actual back cavity volume of 150 further improves the acoustic performance of the microphone packaging structure.

The second metal shell 120 of the microphone packaging structure has a second sound hole 121 , and the side wall 1211 of the second sound hole 121 is recessed toward the inside. The first metal shell 110 has a first sound hole 111, the side wall 1211 of the second sound hole 121 is in sealing connection with the first metal shell 110, and the first sound hole 111 is connected to the second sound hole 121. The sound hole 121 is connected.

In this specific embodiment, the side wall 1111 of the first sound hole 111 protrudes toward the outside and passes through the second deep hole. The cross-section of the second sound hole 121 can be trapezoidal, and the size of the smallest diameter is equivalent to the size of the first sound hole 111, so that after the first sound hole 111 passes through the second sound hole 121, the The gap between the side wall 1211 of the second sound hole 121 and the side wall 1111 of the first sound hole 111 is small, which is easy to be sealed and connected. In this specific embodiment, the side wall of the second sound hole 121 and the side wall of the first sound hole 111 are sealed by a sealing material 122, so that the second cavity 140 is sealed, and the first cavity 130 communicates with the outside through the first sound hole 111 . The sealing material 122 can be at least one of silica gel, epoxy glue, conductive silver glue, solder paste, and high temperature resistant glue. Preferably, the side wall of the first sound hole 111 and the second sound hole 121 are sealed by insulating colloid, so that the first metal shell 110 and the second metal shell 120 are insulated, and the first metal shell 110 and the second metal shell 120 are respectively used as shielding The shell has a double shielding effect on electromagnetic waves.

Since the side wall of the first sound hole 111 is raised, it can prevent the sealing material 122 from falling from the first sound hole 111 into the first cavity 130 and pollute the microphone chip 150 . Affects the performance of the silicon microphone structure.

The first metal shell 110 and/or the second metal shell 120 are sealed and connected to the circuit board 100 through a conductive material. The conductive material can be solder, or silver paste, etc., while realizing the fixed connection between the first metal shell 110 and the second metal shell 120 and the circuit board 100, the electrical connection with the circuit in the circuit board 100 is realized. connect. In this specific embodiment, both the first metal shell 110 and the second metal shell 120 are sealed and connected to the circuit board 100 through a conductive material.

Specifically, both the first metal shell 110 and the second metal shell 120 are electrically connected to the circuit wiring 101 in the circuit board 100 through a conductive material, and are electrically connected to the ground terminal 102 through the circuit wiring 101 . In this specific embodiment, the ground terminal 102 is a pad formed on the second surface of the circuit board 100 . In other specific implementation manners, the ground terminal 102 may also be a ground ring or other ground structures formed on the surface or inside of the circuit board 100 .

In other specific implementation manners, only one of the first metal shell 110 and the second metal shell 120 may be connected to the ground terminal 102 .

The first metal shell 110 and/or the second metal shell 120 can further improve the shielding effect on electromagnetic waves, and can discharge static electricity generated by electromagnetic waves or other reasons through the grounding terminal 102 .

Please refer to FIG. 2 , which is a schematic structural diagram of a silicon microphone package structure according to another embodiment of the present invention.

In this specific embodiment, the second acoustic hole 121 on the second metal shell 120 is covered with a dust-proof film 200 to prevent impurities from entering the first cavity 130 . The dustproof film 200 covers the first acoustic hole 111 at the same time. In a specific embodiment, the dustproof film 200 is a conductive film with holes, so that the second metal shell 120 and the first metal shell 110 form a complete conductor structure to improve the electromagnetic shielding effect. In other specific implementation manners, the second sound hole 121 may only be covered with a general non-conductive dust-proof net.

The dust-proof film 200 can be fixed on the second metal shell 120 by a conductive material such as conductive glue. In this specific embodiment, the dust-proof film 200 covers the outer wall of the second metal shell 120; In other specific implementation manners, the dustproof film 200 may only cover the first acoustic hole 111 .

Please refer to FIG. 3 , which is a schematic structural diagram of a silicon microphone package structure according to another embodiment of the present invention.

In this specific embodiment, the first metal shell 110 has a hole as the first sound hole 301, and the opening of the first sound hole 301 is flush with the main body of the first metal shell 110; The second sound hole 302 on the second metal shell 120 has a side wall 3021 concaved inward. The diameter of the second sound hole 302 is larger than that of the first sound hole 301 , and the first sound hole 301 is located in the orthographic projection area of the second sound hole 302 . The distance between the lower edge of the side wall 3021 of the second sound hole 302 and the first metal shell 110 is relatively small, which facilitates the alignment between the side wall 3021 of the second sound hole 302 and the first metal shell. 110 for sealing. Seal between the side wall 3021 of the second sound hole 302 and the first metal shell 110 through the sealing material 303, and the sealing material can be silica gel, epoxy glue, conductive silver glue, solder paste and resistant At least one of high temperature adhesives.

Please refer to FIG. 4 , which is a schematic structural diagram of a silicon microphone package structure according to another embodiment of the present invention.

On the basis of the silicon microphone packaging structure shown in Figure 3, in this specific embodiment, the first sound hole 301 is also covered with a dust-proof film 400, the dust-proof film 400 has holes and can be a conductive film, In order to improve the shielding effect of the first metal shell 110 on electromagnetic waves.

The dustproof film 400 covers the outer wall of the first metal shell 110 ; in other specific implementation manners, the dustproof film 400 may also cover the inner wall of the first metal shell 110 .

Please refer to FIG. 5 , which is a schematic diagram of a package structure of a silicon microphone according to another embodiment of the present invention.

In this specific embodiment, the circuit board 100 is also formed with conductive slots 500 corresponding to the first metal shell 110 and the second metal shell 120, and the first metal shell 110 and the second metal shell 120 are The two metal shells 120 are respectively inserted into the conductive slots 500 to form an electrical connection with the conductive slots 500 . The conductive slot 500 is also electrically connected to the ground terminal 102 of the circuit board 100 through the circuit wiring 101 in the circuit board 100, and the first metal shell 110 and the second metal shell 120 are respectively passed through the The conductive slot 500 is grounded to improve electromagnetic shielding and antistatic capabilities.

In another specific implementation manner, the circuit board 100 may also only be formed with a conductive slot corresponding to one of the second metal shell 120 and the first metal shell 110 .

The connection between the first metal shell 110 and the second metal shell 120 and the circuit board 100 can also be sealed by conductive or non-conductive glue.

Please refer to FIG. 6 , which is a schematic structural diagram of a silicon microphone package structure according to another embodiment of the present invention.

In this specific embodiment, on the basis of the structure shown in FIG. 1 , an annular protrusion 601 is formed on the side wall 1111 of the first sound hole 111 , and the bottom of the side wall 1222 of the second sound hole 121 is in contact with The annular raised portion 601 is in contact, and when the sealing material 122 is used to seal between the side wall 1222 and the side wall 1111, the raised portion 601 can prevent the sealing material 122 from moving along the first acoustic hole 111. The side wall 1111 flows downward and enters into the second cavity 140 .

The annular raised portion 601 can be integrally formed with the first metal shell 110 and integrally formed by a mold; in other specific embodiments, the annular raised portion 601 can also be fixed by bonding or welding on the surface of the side wall 1111 . The annular protrusion 601 can be made of high temperature resistant materials such as metal and silica gel.

Please refer to FIG. 7 , which is a schematic structural diagram of a silicon microphone package structure according to another embodiment of the present invention.

In this specific embodiment, on the basis of the structure in FIG. 3 , the edge of the first sound hole 301 of the first metal shell has a protruding portion 701 arranged around the first sound hole 301, and the protruding portion 701 can prevent the sealing material 303 from flowing into the first sound hole 301 when the sealing material 303 is used to seal between the side wall 3021 of the second sound hole 302 and the first metal shell 110 . The protruding part 701 can be integrally formed with the first casing 110 , or can be formed with the edge of the first sound hole 301 of the first casing 110 by bonding or welding. The silicon microphone packaging structure of the above-mentioned specific embodiment includes a first metal shell and a second metal shell, and there is a gap between the first metal shell and the second metal shell, through the two-layer metal shell Improve the shielding ability against external electromagnetic waves. Moreover, both the first metal shell and the second metal shell are provided with sound holes, which can avoid the problem of poor welding caused by gas expansion in the cavity during the packaging process.

Further, a channel connected to the back cavity of the microphone chip is formed in the circuit board, which is conducive to increasing the effective volume of the back cavity of the silicon microphone and improving the acoustic performance of the packaging structure of the silicon microphone; the channel is also connected to the first metal shell The second cavity between the body and the second metal shell further expands the effective volume of the back cavity of the microphone chip, thereby improving the acoustic performance of the silicon microphone package structure.

Further, the first metal shell and/or the second metal shell may also be connected to the ground terminal of the circuit board, which is beneficial to improving the electromagnetic shielding effect and improving the electrostatic protection performance.

The specific embodiment of the present invention also provides a silicon microphone packaging method.

Please refer to Fig. 1, in this embodiment, the encapsulation method of silicon microphone encapsulation structure comprises:

A circuit board 100 is provided, with opposite first and second surfaces, and a channel 170 is formed in the circuit board 100; a microphone chip and an ASIC chip 160 are fixed on the circuit board 100, so that the ASIC chip 160 and the The microphone chip 150 and the circuit board 100 are respectively electrically connected, and at the same time, one end of the channel 170 communicates with the back chamber 151 of the microphone chip 150 . In other specific implementation manners, ASIC chips may also be embedded in the circuit board 100 , and there is no need to fix the ASIC chips on the surface of the circuit board 100 .

A first metal shell 110 is provided, the first metal shell 110 is arranged on the first surface of the circuit board 100, and a first cavity 130 is formed between the circuit board 100, and the microphone chip 150 The ASIC chip 160 is located in the first cavity 130 , the first metal casing 110 has a first sound hole 111 , and the first sound hole 111 has a side wall 1111 protruding outward.

A second metal shell 120 is provided, the second metal shell 120 is sleeved on the outside of the first metal shell 110 and fixed on the first surface of the circuit board 100, and the first metal shell A second cavity 140 is formed between the body 110 and the circuit board 100 . The other end of the channel 170 communicates with the second cavity 140 . The second metal shell 120 has a second sound hole 121 , and the second sound hole 121 has a sidewall 1211 concaved toward the inside. The sealing material 122 is used to seal between the side wall 1211 of the second sound hole 121 and the first side wall 1111 . The first sound hole 111 communicates with the second sound hole 121 .

In this specific embodiment, the side wall 1111 of the first sound hole 111 protrudes toward the outside and passes through the second deep hole. The cross-section of the second sound hole 121 can be trapezoidal, and the size of the smallest diameter is equivalent to the size of the first sound hole 111, so that after the first sound hole 111 passes through the second sound hole 121, the The gap between the side wall 1211 of the second sound hole 121 and the side wall 1111 of the first sound hole 111 is small, which is easy to be sealed and connected. In this specific embodiment, the side wall of the second sound hole 121 and the side wall of the first sound hole 111 are sealed by a sealing material 122, so that the second cavity 140 is sealed, and the first cavity 130 communicates with the outside through the first sound hole 111 . The sealing material 122 can be at least one of silica gel, epoxy glue, conductive silver glue, solder paste, and high temperature resistant glue. Preferably, the side wall of the first sound hole 111 and the second sound hole 121 are sealed by insulating colloid, so that the first metal shell 110 and the second metal shell 120 are insulated, and the first metal shell 110 and the second metal shell 120 are respectively used as shielding The shell has a double shielding effect on electromagnetic waves. Since the side wall of the first sound hole 111 is raised, it can prevent the sealing material 122 from falling from the first sound hole 111 into the first cavity 130 and pollute the microphone chip 150 . Affects the performance of the silicon microphone structure.

The first metal shell 110 and the second metal shell 120 can be sealed and fixed on the first surface of the circuit board 100 by welding or glue. In a specific embodiment, the first metal shell 110 and the second metal shell 120 can be sealed and connected to the circuit board 100 through a conductive material. The conductive material may be solder or silver paste. The first metal shell 110 and the second metal shell 120 can be further electrically connected to the circuit in the circuit board 100 through the conductive material. In this specific embodiment, a ground terminal 102 is formed on the circuit board 100, and the first metal shell 110 and the second metal shell 120 are connected to the ground through the circuit wiring 101 of the circuit board 100. The end 102 is used to improve the shielding ability to electromagnetic waves and the antistatic ability.

The ground terminal 102 is a pad formed on the second surface of the circuit board 100 . In other specific implementation manners, the ground terminal 102 may also be a base ring or other ground structures formed with the inside or surface of the circuit board 100 . In other specific implementation manners, only one of the first metal shell 110 and the second metal shell 120 may be connected to the ground terminal 320 .

In another specific embodiment, please refer to FIG. 6 , an annular protrusion 601 is formed on the side wall 1111 of the first sound hole 111 , and the bottom of the side wall 1222 of the second sound hole 121 is in contact with the ring. When the sealing material 122 seals between the side wall 1222 and the side wall 1111 , the protrusion 601 can prevent the sealing material 122 from moving along the side wall 1111 of the first acoustic hole 111 flows downward and enters the second cavity 140 . The annular raised portion 601 can be integrally formed with the first metal shell 110 and integrally formed by a mold; in other specific embodiments, the annular raised portion 601 can also be fixed by bonding or welding on the surface of the side wall 1111 . The annular protrusion 601 can be made of high temperature resistant materials such as metal and silica gel.

Please refer to FIG. 2 , in this specific embodiment, a dustproof film 200 covering the second acoustic hole 121 is also included, and the dustproof film 200 covers the first acoustic hole 111 at the same time. In a specific embodiment, the dustproof film 200 is a conductive film with holes, so that the second metal shell 120 and the first metal shell 110 form a complete conductor structure to improve the electromagnetic shielding effect.

Please refer to FIG. 3 , the first sound hole 301 of the first metal shell 110 is a hole in the first metal shell 110 , and does not have a raised or sunken sidewall. The second acoustic hole 302 on the second metal shell 120 has a side wall 3021 concaved inward. The aperture diameter of the second acoustic hole 302 is larger than the aperture diameter of the first acoustic hole 301, and the first acoustic hole 301 is located in the orthographic projection area of the second acoustic hole 302. Sealing is performed between the side wall 3021 and the first metal shell 110 .

In another specific embodiment, please refer to FIG. 7 , the edge of the first sound hole 301 of the first metal shell also has a protruding portion 701 arranged around the first sound hole 301 , the protruding portion 701 can prevent the sealing material 303 from flowing into the first sound hole 301 when the sealing material 303 is used to seal between the side wall 3021 of the second sound hole 302 and the first metal shell 110 . The protruding part 701 can be integrally formed with the first casing 110 , or can be formed with the edge of the first sound hole 301 of the first casing 110 by bonding or welding.

Please refer to FIG. 4 , in another specific embodiment, it also includes forming a dust-proof film 400 covering the first acoustic hole 301, the dust-proof film 400 has holes, and can be a conductive film to improve the first sound hole 301. The shielding effect of the metal shell 110 on electromagnetic waves. In this specific embodiment, the dustproof film 400 is formed on the outer wall of the first metal shell 110; Dustproof film 400.

Please refer to FIG. 5 , in another specific implementation manner, conductive slots 500 corresponding to the first metal shell 110 and the second metal shell 120 are formed in the circuit board 100; The shell 110 and the second metal shell 120 are inserted into the conductive slot 500 to form an electrical connection with the conductive slot 500 . The conductive slot 500 is also electrically connected to the ground terminal 102 of the circuit board 100 through the circuit wiring 101 in the circuit board 100, thereby grounding the first metal shell 110 and the second metal shell 120 , to improve electromagnetic shielding and antistatic capabilities.

In another specific implementation manner, the circuit board 100 may also only be formed with a conductive slot corresponding to one of the second metal shell 120 and the first metal shell 110 .

The joints between the first metal shell 110 and the second metal shell 120 and the circuit board 100 can be sealed by conductive glue or non-conductive glue.

The above silicon microphone packaging method can improve the electromagnetic wave shielding and anti-static impact capabilities of the formed silicon microphone packaging structure, effectively increase the volume of the back cavity of the microphone chip, and improve the acoustic performance of the silicon microphone packaging structure.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications should also be considered Be the protection scope of the present invention.

Claims (20)

1. a kind of silicon microphone packaging structure characterized by comprising

Circuit board has opposite first surface and second surface；

First metal shell is set on the first surface of the circuit board, and the first cavity, institute are formed between the circuit board The first metal shell is stated with the first acoustic aperture；

Second metal shell is set on the first surface of the circuit board, and is sheathed on outside first metal shell, with The second cavity is formed between first metal shell, circuit board, there is second metal shell side wall to be recessed towards inside The second acoustic aperture, the side wall of second acoustic aperture and first metal shell be tightly connected, first acoustic aperture and described the The connection of two acoustic aperture；

Microphone chip is set in first cavity.

2. the silicon microphone packaging structure according to claim 1, which is characterized in that the first sound of first metal shell Hole has the side wall towards outer projection, and first acoustic aperture passes through second acoustic aperture.

3. the silicon microphone packaging structure according to claim 1, which is characterized in that the side wall of second acoustic aperture with it is described It is tightly connected between first metal shell by sealing material, the sealing material includes: silica gel, epoxy glue, conductive silver glue, weldering At least one of tin cream and high temperature resistant viscose.

4. the silicon microphone packaging structure according to claim 1, which is characterized in that further include: channel is located at the circuit In plate, the one end of the channel is connected to the back chamber of the microphone chip, and the other end is connected to second cavity.

5. the silicon microphone packaging structure according to claim 1, which is characterized in that first metal shell and/or institute The second metal shell is stated to be tightly connected by conductive material and the circuit board.

6. the silicon microphone packaging structure according to claim 5, which is characterized in that be formed with ground connection on the circuit board End, first metal-back and/or second metal-back are connected to the ground terminal by the wiring of the circuit board.

7. the silicon microphone packaging structure according to claim 1, which is characterized in that be formed in the circuit board respectively with First metal shell and/or the corresponding non-conductive socket of second metal shell, first metal-back and/or the second gold medal Belong to shell to be inserted into respectively in the non-conductive socket, be electrically connected with non-conductive socket formation.

8. the silicon microphone packaging structure according to claim 7, which is characterized in that the non-conductive socket is electrically connected to described The ground terminal of circuit board.

9. the silicon microphone packaging structure according to claim 1, which is characterized in that first acoustic aperture and/or the rising tone Dustproof membrane is covered on hole.

10. the silicon microphone packaging structure according to claim 9, which is characterized in that the dustproof membrane is conductive film.

11. a kind of silicon microphone packaging method characterized by comprising

Circuit board is provided, there are opposite first surface and second surface；

Microphone chip is fixed on the circuit board；

First metal shell is provided, first metal shell is set on the first surface of the circuit board, with the electricity The first cavity is formed between the plate of road, the microphone chip is located in first cavity, and first metal shell has the One acoustic aperture；

First metal shell is provided, second metal shell is placed on outside first metal shell and is fixed on the electricity On the first surface of road plate, the second cavity, the second metal shell tool are formed between first metal shell, circuit board The side wall of second acoustic aperture and first metal shell are tightly connected by the second acoustic aperture for having side wall to be recessed towards inside, First acoustic aperture is connected to second acoustic aperture.

12. silicon microphone packaging method according to claim 11, which is characterized in that the first of first metal shell Acoustic aperture has the side wall towards outer projection, and first acoustic aperture passes through second acoustic aperture.

13. silicon microphone packaging method according to claim 11, which is characterized in that by the side wall of second acoustic aperture with First metal shell is tightly connected by sealing material, and the sealing material includes silica gel, epoxy glue, conductive silver glue, weldering At least one of tin cream and high temperature resistant viscose.

14. silicon microphone packaging method according to claim 11, which is characterized in that be also formed in the circuit board logical Road, the one end of the channel are connected to the back chamber of the microphone chip, and the other end is connected to second cavity.

15. silicon microphone packaging method according to claim 11, which is characterized in that by conductive material by described first Metal shell and/or second metal shell and the circuit board are tightly connected.

16. silicon microphone packaging method according to claim 15, which is characterized in that be formed with ground connection on the circuit board End, is connected to the ground connection by the wiring of the circuit board for first metal-back and/or second metal-back End.

17. silicon microphone packaging method according to claim 11, which is characterized in that be formed with difference in the circuit board Non-conductive socket corresponding with first metal shell and/or second metal shell；By first metal-back and/or Two metal-backs are inserted into respectively in the non-conductive socket, are electrically connected with non-conductive socket formation.

18. silicon microphone packaging method according to claim 17, which is characterized in that the non-conductive socket is electrically connected to institute State the ground terminal of circuit board.

19. silicon microphone packaging method according to claim 11, which is characterized in that formed and cover first acoustic aperture And/or second acoustic aperture dustproof membrane.

20. the silicon microphone packaging method according to claim 19, which is characterized in that the dustproof membrane is conductive film.