Silicon microphone packaging structure and packaging method thereof

Abstract

A silicon microphone packaging structure and a packaging method thereof, the silicon microphone packaging structure comprising: a circuit board having a first surface and a second surface opposite to each other; a first metal shell, arranged on the first surface of the circuit board, forming a first cavity with the circuit board, the first metal shell having a first sound hole; a second metal shell, arranged on the first surface of the circuit board, and sleeved on the outside of the first metal shell, forming a second cavity with the first metal shell and the circuit board, the second metal shell having a second sound hole with a side wall recessed toward the inside, the side wall of the second sound hole being sealed and connected to the first metal shell, and the first sound hole being connected to the second sound hole; a microphone chip, arranged in the first cavity. The electromagnetic shielding capability of the silicon microphone packaging structure is improved.

Description

Technical Field

[0001] The present invention relates to the field of MEMS technology, and in particular to a silicon microphone packaging structure and a packaging method thereof. Background Art

[0002] A MEMS microphone usually includes a MEMS chip and an ASIC (Application Specific Integrated Circuit) chip electrically connected to it, wherein the MEMS chip includes a substrate and a diaphragm and a back electrode fixed on the substrate. The diaphragm and the back electrode constitute a capacitor and are integrated on a silicon wafer. Sound enters the microphone through the sound hole and acts on the diaphragm of the MEMS chip. The vibration of the diaphragm changes the distance between the diaphragm and the back electrode, thereby converting the sound signal into an electrical signal.

[0003] Faced with the complex electromagnetic environment and assembly process environment in electronic equipment, MEMS chips are required to have performance such as resistance to electromagnetic environment and good thermal insulation, which puts higher requirements on chip packaging. Traditional packaging structures generally use metal shells 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. There are still many electromagnetic waves that will penetrate the shell and affect the normal operation of the chip in the package.

[0004] How to further improve the shielding ability of silicon microphones against electromagnetic waves in order to improve the performance of the silicon microphone packaging structure is a problem that needs to be solved urgently. Summary of the invention

[0005] 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.

[0006] In order to solve the above problems, the present invention provides a silicon microphone packaging structure, including: a circuit board, having a first surface and a second surface relative to each other; a first metal shell, arranged on the first surface of the circuit board, forming a first cavity between the first metal shell and the circuit board, and the first metal shell has a first sound hole; a second metal shell, arranged on the first surface of the circuit board, and sleeved on the outside of the first metal shell, forming a second cavity between the first metal shell and the circuit board, the second metal shell has a second sound hole with side walls recessed inward, the side walls of the second sound hole are sealed and connected to the first metal shell, and the first sound hole is connected to the second sound hole; a microphone chip is arranged in the first cavity.

[0007] Optionally, the first sound hole of the first metal shell has a side wall protruding toward the outside, and the first sound hole passes through the second sound hole.

[0008] Optionally, the side wall of the second sound hole is sealed and connected to the first metal shell by a sealing material, and the sealing material includes at least one of silicone, epoxy glue, conductive silver glue, solder paste and high-temperature resistant adhesive.

[0009] Optionally, it also 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 of the channel is connected to the second cavity.

[0010] Optionally, the first metal shell and / or the second metal shell is sealed and connected to the circuit board via a conductive material.

[0011] Optionally, a ground terminal is formed on the circuit board, and the first metal shell and / or the second metal shell is connected to the ground terminal through circuit wiring of the circuit board.

[0012] Optionally, conductive slots 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 slots to form an electrical connection with the conductive slots.

[0013] Optionally, the conductive slot is electrically connected to a ground terminal of the circuit board.

[0014] Optionally, the first sound hole and / or the second sound hole is covered with a dustproof film.

[0015] Optionally, the dust-proof film is a conductive film.

[0016] In order to solve the above technical problems, a specific embodiment of the present invention also provides a silicon microphone packaging method, including: providing a circuit board having a first surface and a second surface relative to each other; fixing a microphone chip on the circuit board; providing a first metal shell, setting the first metal shell on the first surface of the circuit board to form a first cavity between the first metal shell and the circuit board, the microphone chip is located in the first cavity, and the first metal shell has a first sound hole; providing a first metal shell, sleeve the second metal shell on the outside of the first metal shell and fix it on the first surface of the circuit board to form a second cavity between the first metal shell and the circuit board, the second metal shell has a second sound hole with a side wall recessed inward, the side wall of the second sound hole is sealed and connected to the first metal shell, and the first sound hole is connected to the second sound hole.

[0017] Optionally, the first sound hole of the first metal shell has a side wall protruding toward the outside, and the first sound hole passes through the second sound hole.

[0018] Optionally, the side wall of the second sound hole is sealed and connected to the first metal shell by a sealing material, and the sealing material includes at least one of silicone, epoxy glue, conductive silver glue, solder paste and high-temperature resistant adhesive.

[0019] Optionally, a channel is formed in the circuit board, one end of the channel is connected to the back cavity of the microphone chip, and the other end of the channel is connected to the second cavity.

[0020] Optionally, the first metal shell and / or the second metal shell is sealed and connected to the circuit board through a conductive material.

[0021] Optionally, a ground terminal is formed on the circuit board, and the first metal shell and / or the second metal shell is connected to the ground terminal through circuit wiring of the circuit board.

[0022] Optionally, conductive slots 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 are respectively inserted into the conductive slots to form electrical connections with the conductive slots.

[0023] Optionally, the conductive slot is electrically connected to a ground terminal of the circuit board.

[0024] Optionally, a dustproof film is formed to cover the first sound hole and / or the second sound hole.

[0025] Optionally, the dust-proof film is a conductive film.

[0026] The silicon microphone packaging structure of the present invention is a top sound-inlet structure, comprising a first metal shell and a second metal shell, with a gap between the two side shells, so that the shielding capability of external electromagnetic waves is improved by the two layers of metal shells; and both the first metal shell and the second metal shell are provided with sound holes, which can avoid the problem of poor welding due to the expansion of gas inside the cavity during the packaging process.

[0027] Furthermore, a channel connected to the back cavity of the microphone chip is formed in the circuit board, which is beneficial to increasing the effective back cavity volume of the silicon microphone and improving the acoustic performance of the silicon microphone packaging structure; the channel also connects to the second cavity between the first metal shell and the second metal shell, further expanding the effective back cavity volume of the microphone chip, thereby improving the acoustic performance of the silicon microphone packaging structure.

[0028] Furthermore, 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 the electrostatic protection performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1It is a structural schematic diagram of a silicon microphone packaging structure according to a specific embodiment of the present invention;

[0030] Figure 2 It is a schematic structural diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention;

[0031] Figure 3 It is a schematic structural diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention;

[0032] Figure 4 It is a schematic structural diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention;

[0033] Figure 5 It is a schematic structural diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention;

[0034] Figure 6 It is a schematic structural diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention;

[0035] Figure 7 It is a schematic structural diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention. DETAILED DESCRIPTION

[0036] The specific implementation methods of the silicon microphone packaging structure and packaging method provided by the present invention are described in detail below with reference to the accompanying drawings.

[0037] Please refer to Figure 1 , is a schematic diagram of a microphone packaging structure according to a specific embodiment of the present invention.

[0038] In this specific implementation, the microphone packaging structure includes: a circuit board 100 , a first metal shell 110 , a second metal shell 120 , and a microphone chip 150 .

[0039] The circuit board 100 has a first surface and a second surface opposite to each other. A circuit wiring is formed inside the circuit board 100 .

[0040] 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 is sleeved outside the first metal shell 110, and forms a second cavity 140 with the first metal shell 110 and the circuit board 100. The size of the second cavity 140 can be set according to the volume requirement of the packaging structure.

[0041] The first metal shell 110 and the second metal shell 120 can be made of the same or different metal materials, including copper-based materials, nickel-based materials, zinc-based materials and other metal materials.

[0042] The first metal shell 110 and the second metal shell 120 are respectively sealed and fixed on the first surface of the circuit board 100. The sealed connection between the first metal shell 110 and the second metal shell 120 and the circuit board 100 can be achieved by welding or gluing.

[0043] The microphone chip 150 is disposed in the first cavity 130. In this specific embodiment, the silicon microphone packaging structure also includes an ASIC chip 160, which is also disposed in the first cavity 130, and the ASIC chip 160 is electrically connected to the microphone chip 150 and the circuit board 100, respectively. 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 sensing signal of the microphone chip 150, and after processing, output it through the circuit board 100. The microphone chip 150 and the ASIC chip 160 can be fixed to the surface of the circuit board 100 by insulating colloid.

[0044] In other specific implementations, the ASIC chip may also be embedded in 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 through welding or wires.

[0045] 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. The first metal shell 110 and the second metal shell 120 serve as electromagnetic shielding layers, which are beneficial to shielding the influence of external electromagnetic waves on the ASIC chip 160 and the microphone chip 150.

[0046] The use of a double-layer metal shell can improve the shielding capability of electromagnetic waves. In addition, in a 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 and achieve a double shielding effect.

[0047] 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 .

[0048] In some specific implementations, the other end of the channel 170 may be located in the circuit board 100 and not connected to the second cavity 140. The channel 170 and the back cavity 151 increase the actual back cavity volume of the microphone chip 150, which is beneficial to improving the acoustic performance of the microphone packaging structure.

[0049] In this specific implementation, the other end of the channel 170 is connected to the second cavity 140, and the second cavity 140 and the channel 170 are connected to the back cavity 151, further increasing the actual back cavity volume of the microphone chip 150 and further improving the acoustic performance of the microphone packaging structure.

[0050] 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, and the side wall 1211 of the second sound hole 121 is sealed and connected to the first metal shell 110, and the first sound hole 111 is connected to the second sound hole 121.

[0051] 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 at the minimum diameter is comparable 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 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, and it is easy to seal and connect. 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 the sealing material 122, so that the second cavity 140 is sealed, and the first cavity 130 is connected to the outside through the first sound hole 111. The sealing material 122 can be at least one of silicone, epoxy glue, conductive silver glue, solder paste and high-temperature resistant adhesive. Preferably, the side wall of the first sound hole 111 and the second sound hole 121 are sealed by an 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 respectively serve as shielding shells, which have a double shielding effect on electromagnetic waves.

[0052] Since the side wall of the first sound hole 111 is raised, the sealing material 122 can be prevented from falling from the first sound hole 111 into the first cavity 130 to contaminate the microphone chip 150 and affect the performance of the silicon microphone structure.

[0053] 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, silver paste, etc., which can realize the electrical connection with the circuit inside the circuit board 100 while realizing the fixed connection between the first metal shell 110 and the second metal shell 120 and the circuit board 100. In this specific embodiment, the first metal shell 110 and the second metal shell 120 are sealed and connected to the circuit board 100 through a conductive material.

[0054] Specifically, the first metal shell 110 and the second metal shell 120 are both electrically connected to the circuit wiring 101 in the circuit board 100 through the 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 embodiments, the ground terminal 102 can also be a grounding ring or other grounding structure formed on the surface or inside of the circuit board 100.

[0055] In other specific implementations, only one of the first metal shell 110 and the second metal shell 120 may be connected to the ground terminal 102 .

[0056] The first metal shell 110 and / or the second metal shell 120 can further improve the shielding effect of electromagnetic waves, and can release static electricity generated by electromagnetic waves or other reasons through the ground terminal 102 .

[0057] Please refer to Figure 2 , which is a schematic structural diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention.

[0058] In this specific embodiment, the second sound hole 121 on the second metal shell 120 is covered with a dustproof film 200 to prevent impurities from entering the first cavity 130. The dustproof film 200 also covers the first sound hole 111. 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 embodiments, the second sound hole 121 can also be covered with only a general non-conductive dustproof net.

[0059] The dustproof film 200 can be fixed on the second metal shell 120 by conductive materials such as conductive glue. In this specific embodiment, the dustproof film 200 covers the outer wall of the second metal shell 120; in other specific embodiments, the dustproof film 200 can also only cover the first sound hole 111.

[0060] Please refer to Figure 3 , which is a schematic structural diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention.

[0061] In this specific embodiment, the first metal shell 110 has a hole as a 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 that is recessed inward. The aperture of the second sound hole 302 is larger than the aperture of the first sound hole 301, and the first sound hole 301 is located in the positive projection area of ​​the second sound hole 302. The distance between the lower side of the side wall 3021 of the second sound hole 302 and the first metal shell 110 is small, which is convenient for sealing the side wall 3021 of the second sound hole 302 and the first metal shell 110. The side wall 3021 of the second sound hole 302 and the first metal shell 110 are sealed by a sealing material 303, and the sealing material can be at least one of silicone, epoxy glue, conductive silver glue, solder paste and high temperature resistant adhesive.

[0062] Please refer to Figure 4 , which is a schematic structural diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention.

[0063] exist Figure 3 Based on the silicon microphone packaging structure shown, in this specific implementation, the first sound hole 301 is also covered with a dustproof film 400. The dustproof film 400 has holes and can be a conductive film to improve the shielding effect of the first metal shell 110 on electromagnetic waves.

[0064] The dustproof film 400 covers the outer wall of the first metal shell 110 ; in other specific implementations, the dustproof film 400 may also cover the inner wall of the first metal shell 110 .

[0065] Please refer to Figure 5 , is a schematic diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention.

[0066] In this specific embodiment, the circuit board 100 is further formed with a conductive slot 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 respectively 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, and the first metal shell 110 and the second metal shell 120 are respectively grounded through the conductive slot 500 to improve electromagnetic shielding and antistatic capabilities.

[0067] In another specific implementation, the circuit board 100 may also be formed with only a conductive slot corresponding to one of the second metal shell 120 and the first metal shell 110 .

[0068] The connection between the first metal shell 110 and the second metal shell 120 and the circuit board 100 may also be sealed by a conductive colloid or a non-conductive colloid.

[0069] Please refer to Figure 6 , which is a schematic structural diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention.

[0070] In this specific implementation, Figure 1 Based on the structure shown, 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 protrusion 601. When the side wall 1222 and the side wall 1111 are sealed by the sealing material 122, the protrusion 601 can prevent the sealing material 122 from flowing downward along the side wall 1111 of the first sound hole 111 and entering the second cavity 140.

[0071] The annular protrusion 601 can be an integral structure with the first metal shell 110 and formed integrally by a mold; in other specific embodiments, the annular protrusion 601 can also be fixed to the surface of the side wall 1111 by bonding or welding. The annular protrusion 601 can be made of high temperature resistant materials such as metal and silicone.

[0072] Please refer to Figure 7 , which is a schematic structural diagram of a silicon microphone packaging structure according to another specific embodiment of the present invention.

[0073] In this specific implementation, Figure 3On the basis of the structure, the edge of the first sound hole 301 of the first metal shell has a protrusion 701 arranged around the first sound hole 301, and the protrusion 701 can prevent the sealing material 303 from flowing into the first sound hole 301 when the side wall 3021 of the second sound hole 302 and the first metal shell 110 are sealed by the sealing material 303. The protrusion 701 can be integrally formed with the first shell 110, or it can be formed with the edge of the first sound hole 301 of the first shell 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, and the shielding ability of external electromagnetic waves is improved by two layers of metal shells. And the first metal shell and the second metal shell are both provided with sound holes, which can avoid the problem of poor welding due to the expansion of gas inside the cavity during the packaging process.

[0074] Furthermore, a channel connected to the back cavity of the microphone chip is formed in the circuit board, which is beneficial to increasing the effective back cavity volume of the silicon microphone and improving the acoustic performance of the silicon microphone packaging structure; the channel also connects to the second cavity between the first metal shell and the second metal shell, further expanding the effective back cavity volume of the microphone chip, thereby improving the acoustic performance of the silicon microphone packaging structure.

[0075] Furthermore, 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 the electrostatic protection performance.

[0076] A specific embodiment of the present invention also provides a silicon microphone packaging method.

[0077] Please refer to Figure 1 In this specific implementation, the packaging method of the silicon microphone packaging structure includes:

[0078] A circuit board 100 is provided, having a first surface and a second surface opposite to each other, 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 is electrically connected to the microphone chip 150 and the circuit board 100, respectively, and one end of the channel 170 is connected to the back cavity 151 of the microphone chip 150. In other specific embodiments, an ASIC chip can also be embedded in the circuit board 100, and it is no longer necessary to fix the ASIC chip on the surface of the circuit board 100.

[0079] A first metal shell 110 is provided, and the first metal shell 110 is disposed on the first surface of the circuit board 100 to form a first cavity 130 between the first metal shell 110 and the circuit board 100. The microphone chip 150 and the ASIC chip 160 are located in the first cavity 130. The first metal shell 110 has a first sound hole 111, and the first sound hole 111 has a side wall 1111 protruding outward.

[0080] A second metal shell 120 is provided, and the second metal shell 120 is sleeved outside the first metal shell 110 and fixed on the first surface of the circuit board 100, so as to form a second cavity 140 between the first metal shell 110 and the circuit board 100. The other end of the channel 170 is connected to the second cavity 140. The second metal shell 120 has a second sound hole 121, and the second sound hole 121 has a side wall 1211 that is recessed toward the inside. The side wall 1211 of the second sound hole 121 is sealed with the first side wall 1111 by a sealing material 122. The first sound hole 111 is connected with the second sound hole 121.

[0081] 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 at the minimum diameter is comparable 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 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, and it is easy to seal and connect. 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 the sealing material 122, so that the second cavity 140 is sealed, and the first cavity 130 is connected to the outside through the first sound hole 111. The sealing material 122 can be at least one of silicone, epoxy glue, conductive silver glue, solder paste and high temperature resistant adhesive. Preferably, the side wall of the first sound hole 111 and the second sound hole 121 are sealed by an insulating colloid, so that the first metal shell 110 and the second metal shell 120 are insulated. The first metal shell 110 and the second metal shell 120 are respectively used as shielding shells to achieve a double shielding effect on electromagnetic waves. Since the side wall of the first sound hole 111 is raised, the sealing material 122 can be prevented from falling from the first sound hole 111 into the first cavity 130, causing pollution to the microphone chip 150 and affecting the performance of the silicon microphone structure.

[0082] 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 gluing. 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 by a conductive material. The conductive material can be solder, silver paste, etc. The first metal shell 110 and the second metal shell 120 can be further electrically connected to the circuit in the circuit board 100 by 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 terminal 102 through the circuit wiring 101 of the circuit board 100 to improve the shielding ability of electromagnetic waves and the anti-static ability.

[0083] The ground terminal 102 is a pad formed on the second surface of the circuit board 100. In other specific embodiments, the ground terminal 102 may also be a base ring or other grounding structure formed inside or on the surface of the circuit board 100. In other specific embodiments, only one of the first metal shell 110 and the second metal shell 120 may be connected to the ground terminal 320.

[0084] In another specific embodiment, please refer to Figure 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 contacts the annular protrusion 601. When the side wall 1222 and the side wall 1111 are sealed by the sealing material 122, the protrusion 601 can prevent the sealing material 122 from flowing downward along the side wall 1111 of the first sound hole 111 and entering the second cavity 140. The annular protrusion 601 can be an integral structure with the first metal shell 110 and formed integrally by a mold; in other specific embodiments, the annular protrusion 601 can also be fixed to the surface of the side wall 1111 by bonding or welding. The annular protrusion 601 can be made of high temperature resistant materials such as metal and silicone.

[0085] Please refer to Figure 2 In this specific embodiment, a dustproof film 200 is formed to cover the second acoustic hole 121, and the dustproof film 200 also covers the first acoustic hole 111. 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.

[0086] Please refer to Figure 3The first sound hole 301 of the first metal shell 110 is a hole on the first metal shell 110, and has no protruding or recessed side walls. The second sound hole 302 on the second metal shell 120 has a side wall 3021 recessed inwardly. The aperture of the second sound hole 302 is larger than the aperture 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, and the side wall 3021 of the second sound hole 302 and the first metal shell 110 are sealed.

[0087] In another specific embodiment, please refer to Figure 7 The edge of the first sound hole 301 of the first metal shell also has a protrusion 701 arranged around the first sound hole 301. The protrusion 701 can prevent the sealing material 303 from flowing into the first sound hole 301 when the side wall 3021 of the second sound hole 302 and the first metal shell 110 are sealed by the sealing material 303. The protrusion 701 can be integrally formed with the first shell 110, or it can be formed separately with the edge of the first sound hole 301 of the first shell 110 by bonding or welding.

[0088] Please refer to Figure 4 In another specific embodiment, a dustproof film 400 is formed to cover the first sound hole 301. The dustproof film 400 has holes and can be a conductive film to improve the shielding effect of the first 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; in other specific embodiments, the dustproof film 400 can also be formed on the inner wall of the first metal shell 110.

[0089] Please refer to Figure 5 In another specific embodiment, a conductive slot 500 corresponding to the first metal shell 110 and the second metal shell 120 is formed in the circuit board 100; the first metal 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, so as to ground the first metal shell 110 and the second metal shell 120 to improve electromagnetic shielding and antistatic capabilities.

[0090] In another specific implementation, the circuit board 100 may also be formed with only a conductive slot corresponding to one of the second metal shell 120 and the first metal shell 110 .

[0091] The connection between the first metal shell 110 and the second metal shell 120 and the circuit board 100 may be sealed by conductive colloid or non-conductive colloid.

[0092] The above-mentioned silicon microphone packaging method can improve the shielding and anti-static impact capabilities of the formed silicon microphone packaging structure against electromagnetic waves, and effectively increase the back cavity volume of the microphone chip, thereby improving the acoustic performance of the silicon microphone packaging structure.

[0093] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A silicon microphone packaging structure, characterized in that: include: a circuit board having a first surface and a second surface opposite to each other; A first metal shell is disposed on a first surface of the circuit board to form a first cavity with the circuit board, and the first metal shell has a first sound hole; A second metal shell is disposed on the first surface of the circuit board and sleeved on the outside of the first metal shell to form a second cavity between the first metal shell and the circuit board, the second metal shell having a second sound hole with a side wall recessed inward, the side wall of the second sound hole being sealed and connected to the first metal shell, and the first sound hole being communicated with the second sound hole; The microphone chip is disposed in the first cavity.

2. The silicon microphone packaging structure according to claim 1, characterized in that: The first sound hole of the first metal shell has a side wall protruding toward the outside, and the first sound hole passes through the second sound hole.

3. The silicon microphone packaging structure according to claim 1, characterized in that: 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: at least one of silicone, epoxy glue, conductive silver glue, and solder paste.

4. The silicon microphone packaging structure according to claim 1, characterized in that: Also includes: A channel is located in the circuit board, one end of the channel is connected to the back cavity of the microphone chip, and the other end of the channel is connected to the second cavity.

5. The silicon microphone packaging structure according to claim 1, characterized in that: The first metal shell and / or the second metal shell is sealed and connected to the circuit board via a conductive material.

6. The silicon microphone packaging structure according to claim 5, characterized in that: A ground terminal is formed on the circuit board, and the first metal shell and / or the second metal shell is connected to the ground terminal through circuit wiring of the circuit board.

7. The silicon microphone packaging structure according to claim 1, characterized in that: Conductive slots 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 slots to form an electrical connection with the conductive slots.

8. The silicon microphone packaging structure according to claim 7, characterized in that: The conductive slot is electrically connected to a ground terminal of the circuit board.

9. The silicon microphone packaging structure according to claim 1, characterized in that: The first sound hole and / or the second sound hole is covered with a dustproof film.

10. The silicon microphone packaging structure according to claim 9, characterized in that: The dustproof film is a conductive film.

11. A silicon microphone packaging method, characterized in that: include: Providing a circuit board having a first surface and a second surface opposite to each other; Fixing a microphone chip on the circuit board; Providing a first metal shell, disposing the first metal shell on the first surface of the circuit board to form a first cavity between the first metal shell and the circuit board, wherein the microphone chip is located in the first cavity, and the first metal shell has a first sound hole; A second metal shell is provided, and the second metal shell is sleeved on the outside of the first metal shell and fixed on the first surface of the circuit board, forming a second cavity between the second metal shell and the first metal shell and the circuit board. The second metal shell has a second sound hole with a side wall recessed inward, and the side wall of the second sound hole is sealed and connected to the first metal shell, and the first sound hole is connected to the second sound hole.

12. The silicon microphone packaging method according to claim 11, characterized in that: The first sound hole of the first metal shell has a side wall protruding toward the outside, and the first sound hole passes through the second sound hole.

13. The silicon microphone packaging method according to claim 11, characterized in that: 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 at least one of silicone, epoxy glue, conductive silver glue, solder paste and high-temperature resistant adhesive.

14. The silicon microphone packaging method according to claim 11, characterized in that: A channel is also formed in the circuit board, one end of the channel is connected to the back cavity of the microphone chip, and the other end of the channel is connected to the second cavity.

15. The silicon microphone packaging method according to claim 11, characterized in that: The first metal shell and / or the second metal shell is sealed and connected to the circuit board through a conductive material.

16. The silicon microphone packaging method according to claim 15, characterized in that: A ground terminal is formed on the circuit board, and the first metal shell and / or the second metal shell is connected to the ground terminal through circuit wiring of the circuit board.

17. The silicon microphone packaging method according to claim 11, characterized in that: Conductive slots 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 are respectively inserted into the conductive slots to form an electrical connection with the conductive slots.

18. The silicon microphone packaging method according to claim 17, characterized in that: The conductive slot is electrically connected to a ground terminal of the circuit board.

19. The silicon microphone packaging method according to claim 11, characterized in that: A dustproof film is formed to cover the first sound hole and / or the second sound hole.

20. The silicon microphone packaging method according to claim 19, characterized in that: The dustproof film is a conductive film.

Images