MEMS microphone and manufacturing method therefor, and electronic device

Abstract

The present application provides an MEMS microphone and a manufacturing method therefor, and an electronic device, capable of reducing the overall size of MEMS microphones and promoting miniaturization design of the MEMS microphones, thereby facilitating the implementation of lightening and thinning design of electronic devices. The MEMS microphone comprises a circuit board, an MEMS chip, and an ASIC chip; the circuit board is provided with a sound hole; the sound hole runs through the circuit board in the thickness direction of the circuit board; the MEMS chip is mounted on the circuit board, covers the sound hole, and is electrically connected to the circuit board; a sound cavity of the MEMS chip is communicated with the sound hole; and the ASIC chip is mounted on a side surface of the MEMS chip and is electrically connected to both the MEMS chip and the circuit board.

Description

MEMS microphone, manufacturing method thereof and electronic device

[0001] The present application claims priority to the Chinese patent application No. 202311602168.5, filed on November 28, 2023, and entitled "MEMS microphone, manufacturing method thereof and electronic device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of acoustic-electric conversion, and in particular to a MEMS microphone, a manufacturing method thereof and an electronic device. BACKGROUND

[0003] MEMS (Micro-Electro-Mechanical Systems) microphones are widely used in various electronic devices due to their high signal-to-noise ratio, good stability and low power consumption. In existing MEMS microphones, the sound signal can be converted into an electric signal through the cooperation of a MEMS chip and an ASIC (Application Specific Integrated Circuit) chip, so that the MEMS microphone can realize the function of receiving sound. However, the position layout of the existing MEMS chip and ASIC chip is unreasonable, which makes the overall volume of the MEMS microphone larger, thereby making it difficult to realize the miniaturization design of the MEMS microphone, and being not conducive to the thin and light design of the electronic device.

[0004] SUMMARY

[0005] The present application provides a MEMS microphone, a manufacturing method thereof and an electronic device, which can reduce the overall volume of the MEMS microphone, promote the miniaturization design of the MEMS microphone, and thus help to realize the thin and light design of the electronic device.

[0006] In a first aspect, the application provides a MEMS microphone, comprising a circuit board, a MEMS chip and an ASIC chip, the circuit board is provided with a sound hole, the sound hole penetrates through the circuit board along the thickness direction of the circuit board, the MEMS chip is mounted on the circuit board and covers the sound hole, and the MEMS chip is electrically connected with the circuit board, the sound cavity of the MEMS chip is in communication with the sound hole, and the ASIC chip is mounted on the side surface of the MEMS chip and is electrically connected with the MEMS chip and the circuit board. The MEMS microphone provided by the application can make the structure of the assembled MEMS chip and ASIC chip more compact, so that the installation space occupied by the MEMS chip and the ASIC chip in the MEMS microphone is reduced, thereby being beneficial to reducing the volume of the whole MEMS microphone and promoting the miniaturization design of the MEMS microphone. On the other hand, the installation area occupied by the MEMS chip and the ASIC chip on the circuit board is reduced, so that the materials required for manufacturing the circuit board and the shell can be saved, and the production cost of the MEMS microphone can be saved.

[0007] In a possible implementation, the ASIC chip comprises a chip body and an active layer, and the active layer and the chip body are laminated on the side surface of the MEMS chip, so that the ASIC chip can be vertically mounted on the side surface of the MEMS chip.

[0008] In a possible implementation, the MEMS chip comprises a back electrode plate, a support frame, a first support layer, a diaphragm and a second support layer, the back electrode plate is fixedly connected to one side of the support frame away from the circuit board, the first support layer is arranged on the surface of the back electrode plate away from the support frame, the diaphragm is arranged on the surface of the first support layer away from the back electrode plate, and the second support layer is arranged on the surface of the support frame away from the back electrode plate; and the active layer and the chip body are laminated on the outer circumferential surface of the support frame. In this arrangement, the diaphragm is spaced apart from the back electrode plate through the first support layer, so that the diaphragm and the back electrode plate jointly form a capacitor structure. When the diaphragm is deformed under the action of the sound pressure of a sound signal, the capacitance value between the diaphragm and the back electrode plate changes. The ASIC chip can detect the capacitance change between the diaphragm and the back electrode plate and convert it into an electric signal output, thereby completing the acoustoelectric conversion and realizing the sound collecting function of the MEMS microphone.

[0009] In a possible implementation, the first support layer is further arranged on a surface of the ASIC chip away from the circuit board, and the diaphragm is further arranged on a surface of the first support layer away from the ASIC chip. In this arrangement, the ASIC chip can support the diaphragm, so that the effective area of the diaphragm is significantly increased, thereby accelerating the response speed of the diaphragm to the sound signal and reducing the sound conversion loss ratio of the diaphragm, and further improving the sound efficiency of the MEMS microphone and the acoustic performance of the MEMS microphone.

[0010] In a possible implementation, the MEMS chip further includes a first wiring layer, a second wiring layer, and a third wiring layer. The first wiring layer and the second wiring layer are both arranged on a side of the back plate away from the support frame. The first wiring layer is electrically connected between the back plate and the ASIC chip. The second wiring layer is arranged in a spaced-apart manner from the first wiring layer and is electrically connected between the diaphragm and the ASIC chip. The third wiring layer is arranged on a side of the support frame facing the circuit board and is electrically connected between the ASIC chip and the circuit board. In this embodiment, the first wiring layer and the second wiring layer are arranged to electrically connect the diaphragm and the back plate to the ASIC chip respectively, so that the ASIC chip can detect the capacitance change between the diaphragm and the back plate, thereby converting the sound signal into an electrical signal and achieving the sound collecting function of the MEMS microphone. The third wiring layer is arranged to electrically connect the ASIC chip to the circuit board, so that the MEMS chip can be electrically connected to the circuit board through the ASIC chip.

[0011] In a possible implementation, the MEMS microphone further includes a connecting layer connected between the outer circumferential surface of the support frame and the ASIC chip. The connecting layer formed between the outer circumferential surface of the support frame and the ASIC chip can electrically connect the MEMS chip to the ASIC chip.

[0012] In a possible implementation, the connecting layer is a wafer bonding layer and electrically connects the first wiring layer, the second wiring layer, the third wiring layer, and the active layer. In this embodiment, the wafer bonding layer is formed by a wafer bonding process to electrically connect the first wiring layer, the second wiring layer, and the third wiring layer to the active layer. In this arrangement, the signal transmission distance between the ASIC chip and the MEMS chip is shortened, thereby helping to improve the signal transmission speed between the MEMS chip and the ASIC chip. At the same time, the gold wire required for wire bonding is not needed to electrically connect the MEMS chip to the ASIC chip, thereby also helping to reduce the production cost of the MEMS microphone.

[0013] In a possible implementation, the connecting layer is a solder layer, the connecting layer includes a first solder part, a second solder part and a third solder part, the first solder part is electrically connected between the first trace layer and the active layer, the second solder part is arranged apart from the first solder part and is electrically connected between the second trace layer and the active layer, and the third solder part is arranged apart from the first solder part and the second solder part on a side of the first solder part and the second solder part facing the circuit board and is electrically connected between the third trace layer and the active layer. In this way, on the one hand, the connection reliability between the MEMS chip and the ASIC chip can be improved, and on the other hand, the welding process is used to fix the MEMS chip and the ASIC chip, which is low in cost and is conducive to reducing the production cost of the MEMS microphone.

[0014] In a possible implementation, the connecting layer is an anisotropic conductive adhesive film, the anisotropic conductive adhesive film includes a first conductive part and a second conductive part, the first conductive part is electrically connected between the first trace layer, the second trace layer and the active layer, and the second conductive part is arranged on a side of the first conductive part facing the circuit board and is electrically connected between the third trace layer and the active layer. In this way, the anisotropic conductive adhesive film is directly bonded between the MEMS chip and the ASIC chip, so that the electrical connection between the MEMS chip and the ASIC chip is achieved, which is simple to operate and is conducive to improving the production efficiency of the MEMS microphone.

[0015] In a possible implementation, the chip body and the active layer are sequentially stacked on a surface of the connecting layer away from the support frame. For example, the ASIC chip further includes a fourth trace layer, a fifth trace layer and a sixth trace layer, the fourth trace layer is electrically connected between the active layer and the first trace layer, the fifth trace layer is arranged apart from the fourth trace layer and is electrically connected between the active layer and the second trace layer, and the sixth trace layer is arranged apart from the fourth trace layer and the fifth trace layer on a side of the fourth trace layer and the fifth trace layer facing the circuit board and is electrically connected between the active layer and the third trace layer. In this way, the traces between the ASIC chip and the MEMS chip are arranged in the interior of the chip, so that the signal transmission distance between the ASIC chip and the MEMS chip is shortened, thereby helping to improve the signal transmission speed between the MEMS chip and the ASIC chip. At the same time, the gold wire required for wire bonding is not needed to achieve the electrical connection between the MEMS chip and the ASIC chip, thereby being conducive to reducing the production cost of the MEMS microphone.

[0016] In a possible implementation, the connecting layer is a die bonding film, and the die bonding film is bonded between the support frame and the chip body; the MEMS microphone further includes a first wire, a second wire and a third wire, the first wire is electrically connected between the first trace layer and the active layer, the second wire is electrically connected between the second trace layer and the active layer, and the third wire is electrically connected between the third trace layer and the active layer. In this arrangement, on the one hand, the lead bonding is used to electrically connect the MEMS chip and the ASIC chip, and the ASIC chip and the circuit board, and the connection reliability between the MEMS chip and the ASIC chip obtained by production is good, and on the other hand, the lead bonding process has a lower cost than the wafer bonding process, and is also conducive to reducing the production cost of the MEMS microphone. At the same time, the trace layer does not need to be additionally arranged in the ASIC chip, which is helpful to simplify the production process flow of the MEMS microphone and improve the production efficiency of the MEMS microphone.

[0017] In a possible implementation, the active layer and the chip body are sequentially stacked on the surface of the connecting layer away from the support frame. For example, the active layer of the ASIC chip is electrically connected to the MEMS chip through the solder layer by using flip-chip bonding. At this time, the trace layer does not need to be additionally arranged in the ASIC chip, so that the production process flow of the MEMS microphone can be simplified, and the production efficiency of the MEMS microphone can be improved.

[0018] In a possible implementation, the back plate is provided with a plurality of through holes, the plurality of through holes penetrate the back plate along the thickness direction of the back plate, are arranged at intervals and are in communication with the sound cavity of the MEMS, so that the sound signal of the external environment can enter the MEMS chip.

[0019] In a possible implementation, the MEMS microphone further includes a housing, the housing is fixedly installed on the circuit board and covers the MEMS chip and the ASIC chip. For example, the housing is made of a metal material. The housing can protect the MEMS chip and the ASIC chip, and can prevent other electromagnetic signals from interfering with the normal use of the MEMS chip and the ASIC chip.

[0020] In a second aspect, the present application also provides an electronic device including a processor and a MEMS microphone as described above, and the processor is electrically connected to the MEMS microphone. The electronic device provided by the present application is helpful to realize the thin and light design of the electronic device by arranging the MEMS microphone as described above.

[0021] In a third aspect, the application further provides a method for manufacturing a MEMS microphone, comprising: providing a microphone intermediate body and a circuit board, the microphone intermediate body comprising a silicon substrate and an ASIC chip, the silicon substrate comprising a support frame intermediate body and a back electrode plate, the back electrode plate being fixedly connected to an upper surface of the support frame intermediate body, the ASIC chip being mounted to a side surface of the silicon substrate and electrically connected to the back electrode plate, the circuit board being provided with a sound hole, the sound hole penetrating through the circuit board along a thickness direction of the circuit board; forming a first sacrificial layer on an upper surface of the silicon substrate and an upper surface of the ASIC chip; forming a diaphragm on a surface of the first sacrificial layer away from the silicon substrate and the ASIC chip, the diaphragm being electrically connected to the ASIC chip; forming a second sacrificial layer on a lower surface of the silicon substrate and a lower surface of the ASIC chip; etching the second sacrificial layer, the silicon substrate and the first sacrificial layer from the lower surface of the silicon substrate to the upper surface of the silicon substrate to form a second support layer, a support frame and a first support layer, thereby obtaining a MEMS chip; and mounting the MEMS chip and the ASIC chip to the circuit board to obtain the MEMS microphone, wherein the MEMS chip covers the sound hole and is electrically connected to the circuit board, an acoustic cavity of the MEMS chip is in communication with the sound hole, and the ASIC chip is electrically connected to the circuit board. The method for manufacturing the MEMS microphone provided in the embodiment can fix the ASIC chip to the side surface of the MEMS chip through a wafer bonding process, so that the structure of the assembled MEMS chip and ASIC chip is more compact, and the installation space of the MEMS chip and the ASIC chip in the MEMS microphone is reduced, thereby facilitating the reduction of the overall volume of the MEMS microphone, promoting the miniaturization design of the MEMS microphone, and further helping to realize the light and thin design of the electronic device. On the other hand, the installation area of the MEMS chip and the ASIC chip on the circuit board is reduced, and compared with the area of the circuit board used in the existing MEMS microphone, the area of the circuit board used in the MEMS microphone provided in the application is reduced by 50%, so that the materials required for manufacturing the circuit board and the shell can be saved, and the production cost of the MEMS microphone can be saved.

[0022] In a possible implementation, in the step of providing the microphone intermediate body and the circuit board, a first wiring layer is formed on an upper surface of the back electrode plate and an upper surface of the ASIC chip, the first wiring layer being electrically connected between the back electrode plate and the ASIC chip; and in the step of forming the first sacrificial layer on the upper surface of the silicon substrate and the upper surface of the ASIC chip, the first sacrificial layer covers the first wiring layer. The first wiring layer can be provided to electrically connect the back electrode plate and the ASIC chip.

[0023] In a possible implementation, after the step of forming the first sacrificial layer on the upper surface of the silicon substrate and the upper surface of the ASIC chip, and before the step of forming the diaphragm on the surface of the first sacrificial layer away from the silicon substrate and the ASIC chip, the method further includes: forming a first electrical connection part in the first sacrificial layer, the first electrical connection part is arranged apart from the first wiring layer and is electrically connected to the ASIC chip; after the step of forming the diaphragm on the surface of the first sacrificial layer away from the silicon substrate and the ASIC chip, and before the step of forming the second sacrificial layer on the lower surface of the silicon substrate and the lower surface of the ASIC chip, the method further includes: forming a second electrical connection part in the diaphragm and the first sacrificial layer, the second electrical connection part is electrically connected to the first electrical connection part and the diaphragm, to obtain a second wiring layer, the second wiring layer is electrically connected between the diaphragm and the ASIC chip. By arranging the second wiring layer, the diaphragm and the ASIC chip can be electrically connected.

[0024] In a possible implementation, after the step of forming the diaphragm on the surface of the first sacrificial layer away from the silicon substrate and the ASIC chip, and before the step of forming the second sacrificial layer on the lower surface of the silicon substrate and the lower surface of the ASIC chip, the method further includes: forming a third electrical connection part on the lower surface of the silicon substrate and the lower surface of the ASIC chip, the third electrical connection part is electrically connected to the ASIC chip; in the step of forming the second sacrificial layer on the lower surface of the silicon substrate and the lower surface of the ASIC chip, the second sacrificial layer covers the third electrical connection part; after the step of forming the second sacrificial layer on the lower surface of the silicon substrate and the lower surface of the ASIC chip, and before the step of etching the second sacrificial layer, the silicon substrate and the first sacrificial layer in the direction from the lower surface of the silicon substrate to the upper surface of the silicon substrate, the method further includes: forming a fourth electrical connection part in the second sacrificial layer, the fourth electrical connection part is electrically connected to the third electrical connection part, to obtain a third wiring layer, the third wiring layer is electrically connected to the ASIC chip. By arranging the third wiring layer, the ASIC chip and the circuit board can be electrically connected.

[0025] In a possible implementation, in the step of providing the microphone intermediate body and the circuit board, the ASIC chip is mounted on the side surface of the silicon substrate to obtain a microphone pre-product; the silicon substrate is etched to form a plurality of etching grooves, the plurality of etching grooves are arranged at intervals, and the openings of the plurality of etching grooves are located on the upper surface of the silicon substrate; the microphone pre-product is subjected to annealing treatment to form a cavity in the silicon substrate to obtain a back plate intermediate body and the support frame intermediate body, the back plate intermediate body is fixedly connected to the upper surface of the support frame intermediate body; and the back plate intermediate body is etched to form a plurality of through holes to obtain the back plate, wherein the plurality of through holes are arranged at intervals and penetrate the back plate along the thickness direction of the back plate and are in communication with the cavity.

[0026] In a possible implementation, in the step of mounting the MEMS chip to the circuit board to obtain the MEMS microphone, the housing is fixedly mounted on the circuit board and covers the MEMS chip and the ASIC chip. The housing can protect the MEMS chip and the ASIC chip and prevent other electromagnetic signals from interfering with the normal use of the MEMS chip and the ASIC chip.

[0027] In a fourth aspect, the present application further provides a preparation method of a MEMS microphone, comprising: providing a MEMS chip, an ASIC chip and a circuit board, the circuit board being provided with a sound hole, the sound hole penetrating the circuit board along the thickness direction of the circuit board; mounting the ASIC chip to the side surface of the MEMS chip, wherein the ASIC chip is electrically connected to the MEMS chip; and mounting the MEMS chip to the circuit board to obtain the MEMS microphone, wherein the MEMS chip covers the sound hole and is electrically connected to the circuit board, the sound cavity of the MEMS chip is in communication with the sound hole, and the ASIC chip is electrically connected to the circuit board. The preparation method of the MEMS microphone provided in the embodiment makes the structure of the assembled MEMS chip and ASIC chip more compact, and reduces the installation space of the MEMS chip and the ASIC chip in the MEMS microphone, thereby facilitating the reduction of the volume of the MEMS microphone as a whole, promoting the miniaturization design of the MEMS microphone, and further helping to realize the light and thin design of the electronic device. On the other hand, the installation area occupied by the MEMS chip and the ASIC chip on the circuit board is reduced, so that the materials required for manufacturing the circuit board and the housing can be saved, and the production cost of the MEMS microphone can be saved.

[0028] In a possible implementation, the ASIC chip comprises a chip body and an active layer, and the active layer is arranged in a stack with the chip body. In the step of mounting the ASIC chip to the side surface of the MEMS chip, the chip body is wafer bonded to the side surface of the MEMS chip with a surface of the active layer facing away from the chip body, so as to form a connection layer. In this preparation method, the wirings between the ASIC chip and the MEMS chip and the wirings between the ASIC chip and the circuit board are arranged in the interior of the chip, so that the signal transmission distance between the ASIC chip and the MEMS chip and between the ASIC chip and the circuit board is shortened, thereby helping to improve the signal transmission speed between the MEMS chip, the ASIC chip and the circuit board.

[0029] In a possible implementation, the ASIC chip comprises a chip body and an active layer, and the active layer is arranged in a stack with the chip body. In the step of mounting the ASIC chip to the side surface of the MEMS chip, the chip body is soldered to the side surface of the MEMS chip with a surface of the active layer facing away from the chip body, so as to form a first solder part, a second solder part and a third solder part, thereby obtaining a connection layer. In this preparation method, the soldering process is used to fix the MEMS chip and the ASIC chip, which is low in cost and helps to reduce the production cost of the MEMS microphone.

[0030] In a possible implementation, in the step of mounting the ASIC chip to the side surface of the MEMS chip, anisotropic conductive adhesive film is provided, and the anisotropic conductive adhesive film is fixedly mounted to the side surface of the MEMS chip, and then the ASIC chip is mounted to a surface of the anisotropic conductive adhesive film facing away from the MEMS chip. Through the anisotropic conductive adhesive film, the electrical connection between the MEMS chip and the ASIC chip is achieved, which is simple to operate and helps to improve the production efficiency of the MEMS microphone.

[0031] In a possible implementation, the MEMS chip comprises a back electrode plate, a support frame, a first support layer, a diaphragm, a first wiring layer, a second wiring layer and a third wiring layer, the back electrode plate is fixedly connected to one side of the support frame away from the circuit board, the first support layer is arranged on a surface of the back electrode plate away from the support frame, the diaphragm is arranged on a surface of the first support layer away from the back electrode plate, the first wiring layer and the second wiring layer are both arranged on one side of the back electrode plate away from the support frame, the second wiring layer is arranged in a spaced manner with the first wiring layer, and the third wiring layer is arranged on one side of the support frame facing the circuit board. The ASIC chip comprises a chip body and an active layer, and the active layer is arranged in a stacked manner with the chip body. In the step of mounting the ASIC chip to the side of the MEMS chip, the following steps are included: providing a chip bonding film, a first lead wire, a second lead wire and a third lead wire; mounting the chip bonding film to the outer circumferential surface of the support frame in a fixed manner; mounting the ASIC chip to a surface of the chip bonding film away from the support frame, and the chip body and the active layer are arranged in a stacked manner on the surface of the chip bonding film away from the support frame; electrically connecting the first lead wire between the first wiring layer and the active layer; electrically connecting the second lead wire between the second wiring layer and the active layer; and electrically connecting the third lead wire between the third wiring layer and the active layer. In the preparation method, the lead bonding is used to electrically connect the MEMS chip, the ASIC chip and the circuit board, and the production cost is low. Meanwhile, the ASIC chip does not need to be additionally provided with a wiring layer, which is helpful to simplify the production process flow of the MEMS microphone and improve the production efficiency of the MEMS microphone. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background art, the drawings needed to be used in the embodiments of the present application or the background art will be described below.

[0033] FIG. 1 is a structural schematic diagram of an electronic device according to an embodiment of the present application;

[0034] FIG. 2 is a structural schematic diagram of a MEMS microphone in the electronic device shown in FIG. 1;

[0035] FIG. 3 is a structural schematic diagram of the MEMS microphone shown in FIG. 2 after being cut along the A-A line in a first embodiment;

[0036] FIG. 4 is a structural schematic diagram of an ASIC chip in the MEMS microphone shown in FIG. 3;

[0037] FIG. 5 is a structural schematic diagram of the MEMS microphone shown in FIG. 2 after being cut along the A-A line in a second embodiment;

[0038] Fig. 6 is a structural schematic view of the MEMS microphone shown in Fig. 2 along the line A-A in a third embodiment after being cut open;

[0039] Fig. 7 is a structural schematic view of the MEMS microphone shown in Fig. 2 along the line A-A in a fourth embodiment after being cut open;

[0040] Fig. 8 is a structural schematic view of the MEMS microphone shown in Fig. 2 along the line A-A in a fifth embodiment after being cut open;

[0041] Fig. 9 is a structural schematic view of the MEMS microphone shown in Fig. 2 along the line A-A in a sixth embodiment after being cut open;

[0042] Fig. 10 is a structural schematic view of the MEMS microphone shown in Fig. 2 along the line A-A in a seventh embodiment after being cut open;

[0043] Fig. 11 is a flow schematic view of a preparation method of a first MEMS microphone provided by an embodiment of the present application;

[0044] Fig. 12 is a structural schematic view of a silicon substrate of a microphone intermediate provided in step S1;

[0045] Fig. 13 is a structural schematic view of a microphone preform provided in step S11;

[0046] Fig. 14 is a structural schematic view of the silicon substrate after a plurality of etching grooves are formed on the silicon substrate in step S12;

[0047] Fig. 15 is a structural schematic view of the silicon substrate after a cavity is formed in the interior of the silicon substrate in step S13;

[0048] Fig. 16 is a structural schematic view of the back plate intermediate after a first wiring layer is formed on the upper surface of the back plate intermediate and the upper surface of the ASIC chip in step S14;

[0049] Fig. 17 is a structural schematic view of the back plate after step S15;

[0050] Fig. 18 is a structural schematic view of the silicon substrate after a first electrical connection is formed in the first sacrificial layer in step S3;

[0051] Fig. 19 is a structural schematic view of the silicon substrate after a diaphragm is formed on the surface of the first sacrificial layer away from the silicon substrate and the ASIC chip in step S4;

[0052] Fig. 20 is a structural schematic view of the silicon substrate after a second wiring layer is obtained in step S5;

[0053] Fig. 21 is a structural schematic view of the silicon substrate after a third electrical connection is formed on the lower surface of the silicon substrate and the lower surface of the ASIC chip in step S6;

[0054] Fig. 22 is a structural schematic view of the silicon substrate after a third wiring layer is obtained in step S8;

[0055] FIG. 23 is a structural schematic diagram of a MEMS chip obtained in step S9;

[0056] FIG. 24 is a flow schematic diagram of a preparation method of a second MEMS microphone provided by an embodiment of the present application;

[0057] FIG. 25 is a structural schematic diagram of a silicon substrate after a plurality of etching grooves are formed in step S101';

[0058] FIG. 26 is a structural schematic diagram of a back plate intermediate body and a support plate intermediate body obtained in step S102';

[0059] FIG. 27 is a structural schematic diagram of a back plate intermediate body after a first wiring layer is formed on the upper surface of the back plate intermediate body in step S103';

[0060] FIG. 28 is a structural schematic diagram of a back plate obtained in step S104';

[0061] FIG. 29 is a structural schematic diagram of a first electric connection part formed in the first sacrificial layer in step S106';

[0062] FIG. 30 is a structural schematic diagram of a diaphragm formed on the surface of the first sacrificial layer away from the silicon substrate in step S107';

[0063] FIG. 31 is a structural schematic diagram of a second wiring layer obtained in step S108';

[0064] FIG. 32 is a structural schematic diagram of a third electric connection part formed on the lower surface of the silicon substrate in step S109';

[0065] FIG. 33 is a structural schematic diagram of a third wiring layer obtained in step S111';

[0066] FIG. 34 is a structural schematic diagram of a MEMS chip obtained in step S112'. DETAILED DESCRIPTION

[0067] The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0068] Please refer to FIG. 1 and FIG. 2, FIG. 1 is a structural schematic diagram of an electronic device 100 provided by an embodiment of the present application, and FIG. 2 is a structural schematic diagram of a MEMS microphone 120 in the electronic device 100 shown in FIG. 1.

[0069] An electronic device 100 is provided by an embodiment of the present application, which can be but is not limited to a mobile phone, a tablet computer, a television, a headset, a sound system, a personal computer (PC), a smart speaker, a smart screen, a vehicle-mounted display screen, etc. The electronic device 100 can also be a gyroscope or other MEMS device with a large cavity.

[0070] In this embodiment, the electronic device 100 can include a shell 110, a middle frame 130, a processor 140, a display screen 150, and a MEMS microphone 120. The shell 110 and the display screen 150 are both mounted on the middle frame 130. The display screen 150 is arranged opposite to the shell 110. The display screen 150 is configured to display a picture. The middle frame 130 is located between the display screen 150 and the shell 110. The processor 140 and the MEMS microphone 120 are both mounted inside the shell 110. The shell 110 can protect the processor 140 and the MEMS microphone 120. The MEMS microphone 120 is electrically connected to the processor 140. The processor 140 can process the sound signal received by the MEMS microphone, so that the MEMS microphone 120 can realize the sound collecting function.

[0071] Please refer to FIG. 3, which is a structural schematic diagram of the MEMS microphone 120 along the A-A line in the first embodiment after being cut open.

[0072] The MEMS microphone 120 includes a circuit board 10, a shell 20, a MEMS chip 30, and an ASIC chip 40. The MEMS chip 30, the ASIC chip 40, and the shell 20 are all arranged on one side of the circuit board 10. The circuit board 10 is a printed circuit board (PCB). The circuit board 10 is provided with a sound hole 101, which penetrates the circuit board 10 along the thickness direction of the circuit board 10, so as to facilitate the inflow of sound signals. The MEMS chip 30 is fixedly mounted on the circuit board 10 and covers the sound hole 101 of the circuit board 10. The ASIC chip 40 is mounted on the side surface of the MEMS chip 30 and is electrically connected to the MEMS chip 30 and the circuit board 10. The ASIC chip 40 and the MEMS chip 30 can be fixedly connected through a wafer bonding process. The MEMS chip 30 is configured to perceive and detect the sound signal flowing from the sound hole 101 and convert the sound signal into an electrical signal transmitted to the ASIC chip 40. The ASIC chip 40 receives the electrical signal output by the MEMS chip 30 and processes and amplifies the electrical signal, so that the MEMS microphone 120 can provide the electronic device 100 with the sound collecting function. The shell 20 is fixedly mounted on the circuit board 10 and covers the MEMS chip 30 and the ASIC chip 40. For example, the shell 20 is made of metal material. The shell 20 can protect the MEMS chip 30 and the ASIC chip 40 and prevent other electromagnetic signals from interfering with the normal use of the MEMS chip 30 and the ASIC chip 40.

[0073] In addition, when the MEMS chip 30 and the ASIC chip 40 are fixed to the circuit board 10, the MEMS chip 30 and the ASIC chip 40 are both spaced apart from the circuit board 10. At this time, the MEMS microphone 120 can further include a fixing member 50. The fixing member 50 is electrically connected between the MEMS chip 30 and the circuit board 10 to achieve a fixed connection between the MEMS chip 30 and the circuit board 10, thereby enabling the ASIC chip 40 to be electrically connected to the circuit board 10. For example, the fixing member 50 can be a solder ball formed during soldering of the MEMS chip 30 and the circuit board 10.

[0074] Please refer to FIG. 3. The MEMS chip 30 includes a back plate 31, a support frame 32, a first support layer 34, a diaphragm 35, and a second support layer 38. The back plate 31 is fixedly connected to one side of the support frame 32 facing away from the circuit board 10. The first support layer 34 is disposed on a surface of the back plate 31 facing away from the support frame 32. The diaphragm 35 is disposed on a surface of the first support layer 34 facing away from the back plate 31. The second support layer 38 is disposed on a surface of the support frame 32 facing away from the back plate 31.

[0075] In this embodiment, the support frame 32 and the back plate 31 can be integrally formed. The support frame 32 and the back plate 31 enclose an acoustic cavity 30a. Specifically, an opening of the acoustic cavity 30a is disposed to face the circuit board 10. The acoustic cavity 30a is in communication with the sound hole 101, so that sound signals from the external environment can enter the MEMS chip 30. The back plate 31 is provided with a plurality of through holes 311. The plurality of through holes 311 each penetrate the back plate 31 along a thickness direction of the back plate 31 and are spaced apart from each other. Each of the through holes 311 is in communication with the acoustic cavity 30a, so that sound signals can pass through the back plate 31.

[0076] In this embodiment, the first support layer 34 is disposed on a surface of the back plate 31 facing away from the support frame 32 and a surface of the ASIC chip 40 facing away from the circuit board 10. Specifically, a peripheral surface of the first support layer 34 exceeds a peripheral surface of the back plate 31 and covers at least part of the surface of the ASIC chip 40 facing away from the circuit board 10. The thickness of the first support layer 34 is between 1 μm and 4 μm. The first support layer 34 is provided with a relief hole 341 penetrating the first support layer 34 along a thickness direction of the first support layer 34. The relief hole 341 avoids the plurality of through holes 311 of the back plate 31, so as to avoid the first support layer 34 from obstructing the transmission of sound signals.

[0077] In this embodiment, the diaphragm 35 is arranged on the surface of the first support layer 34 away from the back plate 31 and the surface of the first support layer 34 away from the ASIC chip 40. The orthographic projection of the diaphragm 35 on the back plate 31 covers at least part of the surface of the ASIC chip 40 away from the circuit board 10. For example, the diaphragm 35 is made of polysilicon. The thickness of the diaphragm 35 is between 0.2 μm and 1 μm. In this embodiment, the orthographic projection of the diaphragm 35 on the back plate 31 covers the plurality of through holes 311 of the back plate 31 and the ASIC chip 40. That is, the diaphragm 35 is located on the top side of the back plate 31. At this time, the MEMS microphone 120 is in an upper pickup mode.

[0078] In this arrangement, the ASIC chip 40 can support the diaphragm 35, so that the effective area of the diaphragm 35 is significantly increased, thereby accelerating the response speed of the diaphragm 35 to the sound signal and reducing the sound conversion loss ratio of the diaphragm 35, and further improving the acoustic efficiency of the MEMS microphone 120 and the acoustic performance of the MEMS microphone 120. The acoustic efficiency of the MEMS microphone 120 provided by the present application is 1.76 times that of the existing MEMS microphone 120.

[0079] In other embodiments, the diaphragm 35 can be fixedly connected to the support frame 32 and arranged on the side of the back plate 31 facing the circuit board 10 and spaced apart from the back plate 31. That is, the diaphragm 35 is located on the bottom side of the back plate 31. At this time, the MEMS microphone 120 is in a bottom pickup mode. In this arrangement, the diaphragm 35 and the back plate 31 do not need to be additionally provided with the first support layer 34, thereby simplifying the structure of the MEMS chip 30 and facilitating the reduction of the production process flow of the MEMS chip 30.

[0080] In this embodiment, the diaphragm 35 and the back plate 31 together form a capacitor structure. It can be understood that the sound signal in the external environment enters the sound cavity 30a of the MEMS chip 30 through the sound hole 101 of the circuit board 10 and acts on the diaphragm 35 through the back plate 31. When the diaphragm 35 is deformed by the sound pressure of the sound signal, the capacitance between the diaphragm 35 and the back plate 31 changes. The ASIC chip 40 can detect the capacitance change between the diaphragm 35 and the back plate 31 and convert it into an electrical signal output, thereby completing the acoustoelectric conversion and enabling the MEMS microphone 120 to realize the sound collecting function.

[0081] In the embodiment, the second support layer 38 is arranged on the surface of the support frame 32 facing the circuit board 10 and the surface of the ASIC chip facing the circuit board 10, and surrounds the opening of the sound cavity 30a. Specifically, the peripheral surface of the second support layer 38 exceeds the peripheral surface of the support frame 32, and covers at least part of the surface of the ASIC chip 40 facing the circuit board 10. The MEMS chip 30 can be fixedly connected to the circuit board 10 through the second support layer 38.

[0082] The MEMS chip 30 further comprises a first wiring layer 33, a second wiring layer 36 and a third wiring layer 37. For example, the first wiring layer 33, the second wiring layer 36 and the third wiring layer 37 are all made of copper. In other embodiments, the first wiring layer 33, the second wiring layer 36 and the third wiring layer 37 can also be made of aluminum.

[0083] In the embodiment, the first wiring layer 33 and the second wiring layer 36 are both arranged on the side of the back plate 31 away from the support frame 32. The first wiring layer 33 is arranged on the surface of the back plate 31 away from the support frame 32, covers the first support layer 34, and is electrically connected between the back plate 31 and the ASIC chip 40. For example, the first wiring layer 33 is arranged on the surface of the back plate 31 away from the support frame 32 and the surface of the side of the ASIC chip 40 close to the back plate 31. The end of the first wiring layer 33 away from the back plate 31 is exposed relative to the peripheral surface of the first support layer 34. In other embodiments, the first wiring layer 33 can also be arranged on the surface of the back plate 31 away from the support frame 32, or the first wiring layer 33 can also be arranged on the surface of the side of the ASIC chip 40 close to the back plate 31, which is not limited in the embodiments of the application.

[0084] In the embodiment, the second wiring layer 36 is arranged in the interior of the diaphragm 35 and the first support layer 34, and is electrically connected between the diaphragm 35 and the ASIC chip 40. For example, the end of the second wiring layer 36 away from the diaphragm 35 is exposed relative to the surface of the first support layer 34 facing the back plate 31. Specifically, the second wiring layer 36 comprises a first electrically connecting part 361 and a second electrically connecting part 362 connected to each other. The first electrically connecting part 361 is arranged in the interior of the first support layer 34 and is spaced apart from the first wiring layer 33. The second electrically connecting part 362 is electrically connected to the first electrically connecting part 361 and the diaphragm 35. Part of the second electrically connecting part 362 is arranged in the interior of the first support layer 34, and the other part is arranged in the interior of the diaphragm 35.

[0085] It can be understood that, by arranging the first wiring layer 33 and the second wiring layer 36, the diaphragm 35 and the back plate 31 can be electrically connected to the ASIC chip 40 respectively, so that the ASIC chip 40 can detect the capacitance change between the diaphragm 35 and the back plate 31, thereby realizing the conversion between the sound signal and the electrical signal, and further realizing the sound collecting function of the MEMS microphone 120.

[0086] The third wiring layer 37 is arranged on the side of the support frame 32 facing the circuit board 10 and is electrically connected between the ASIC chip 40 and the circuit board 10. The end of the third wiring layer 37 close to the ASIC chip 40 is exposed relative to the surface of the support frame 32 facing the second support layer 38. Specifically, the third wiring layer 37 can include a third electrical connection part 371 and a fourth electrical connection part 372 connected to each other. The third electrical connection part 371 is arranged across the surface of the support frame 32 facing the circuit board 10 and the surface of the ASIC chip facing the circuit board 10. The fourth electrical connection part 372 is electrically connected to the third electrical connection part 371.

[0087] In this embodiment, the third wiring layer 37 can be multiple. The multiple third wiring layers 37 are arranged at intervals. For example, the third wiring layer 37 is two. Both of the two third wiring layers 37 are electrically connected to the ASIC chip to realize the transmission of different electrical signals between the ASIC chip 40 and the circuit board 10. It should be noted that the shape and arrangement of each third wiring layer 37 can be the same or different, which is determined according to the specific electrical connection mode of the MEMS chip and the ASIC chip.

[0088] Please refer to FIG. 4, which is a structural schematic diagram of the ASIC chip 40 in the MEMS microphone 120 shown in FIG. 3.

[0089] The ASIC chip 40 includes a chip body 41 and an active layer 42, and the chip body 41 and the active layer 42 are laminated on the side of the MEMS chip 30. Specifically, the active layer 42 is arranged on the surface of the chip body 41 away from the MEMS chip 30. The ASIC chip 40 further includes a fourth wiring layer 43, a fifth wiring layer 44 and a sixth wiring layer 45. The fourth wiring layer 43, the fifth wiring layer 44 and the sixth wiring layer 45 are arranged in the interior of the chip body 41 and are arranged at intervals, and are all electrically connected to the active layer 42. For example, the materials of the fourth wiring layer 43, the fifth wiring layer 44 and the sixth wiring layer 45 are all copper. In other embodiments, the materials of the fourth wiring layer 43, the fifth wiring layer 44 and the sixth wiring layer 45 can also be aluminum, and the embodiments of the present application do not limit this.

[0090] In the embodiment, the fourth trace layer 43 is electrically connected between the active layer 42 and the first trace layer 33, so that the active layer 42 of the ASIC chip 40 is electrically connected with the back plate 31. Specifically, the end of the fourth trace layer 43 away from the active layer 42 is exposed relative to the surface of the chip body 41 facing away from the circuit board 10, and is electrically connected with the first trace layer 33.

[0091] The fifth trace layer 44 is spaced apart from the fourth trace layer 43 and is electrically connected between the active layer 42 and the second trace layer 36, so that the active layer 42 of the ASIC chip 40 is electrically connected with the diaphragm 35. Specifically, the end of the fifth trace layer 44 away from the active layer 42 is exposed relative to the surface of the chip body 41 facing away from the circuit board 10, and is electrically connected with the second trace layer 36.

[0092] The sixth trace layer 45 is located on the side of the fourth trace layer 43 and the fifth trace layer 44 facing the circuit board 10, and is spaced apart from the fourth trace layer 43 and the fifth trace layer 44 and is electrically connected between the active layer 42 and the third trace layer 37. Specifically, the end of the sixth trace layer 45 away from the active layer 42 is exposed relative to the surface of the chip body 41 facing the circuit board 10, and is electrically connected with the third trace layer 37. In the embodiment, the sixth trace layer 45 can be multiple. The multiple sixth trace layers 45 are spaced apart from each other. Each sixth trace layer 45 is electrically connected between the active layer 42 and one third trace layer 37. Exemplarily, the sixth trace layer 45 has two.

[0093] In addition, the MEMS microphone 120 further comprises a connecting layer 60 connected between the outer circumferential surface of the support frame 32 and the ASIC chip 40, so that the MEMS chip 30 can be electrically connected with the ASIC chip 40. In the embodiment, the connecting layer 60 is a wafer bonding layer 61, and is electrically connected with the first trace layer 33, the second trace layer 36, the third trace layer 37 of the MEMS chip 30 and the active layer 42 of the ASIC chip 40. It should be noted that the wafer bonding layer 61 is formed by wafer bonding process, which combines the outer circumferential surface of the support frame 32 in the MEMS chip 30 and the surface of the chip body 41 in the ASIC chip facing away from the active layer 42.

[0094] In the embodiment, after the ASIC chip 40 is fixedly connected to the side surface of the MEMS chip 30, the MEMS chip 30 is fixed to the surface of the circuit board 10. At this time, one end of the third wiring layer 37 away from the ASIC chip 40 is electrically connected to the circuit board 10, so that the ASIC chip 40 is electrically connected to the circuit board 10, and the MEMS chip 30 is electrically connected to the circuit board 10 through the ASIC chip 40. In this arrangement, the wiring between the ASIC chip 40 and the MEMS chip 30 and the wiring between the ASIC chip 40 and the circuit board 10 are arranged inside the chips, so that the signal transmission distance between the ASIC chip 40 and the MEMS chip 30 and between the ASIC chip 40 and the circuit board 10 is shortened, thereby helping to improve the signal transmission speed between the MEMS chip 30, the ASIC chip 40 and the circuit board 10. At the same time, the electrical connection between the MEMS chip 30 and the ASIC chip 40 and between the ASIC chip 40 and the circuit board 10 does not need to use gold wires required for wire bonding, thereby also helping to reduce the production cost of the MEMS microphone 120.

[0095] In the embodiment, by fixedly installing the ASIC chip 40 to the side surface of the MEMS chip 30, on the one hand, the structure of the assembled MEMS chip 30 and ASIC chip 40 is more compact, and the installation space of the MEMS chip 30 and the ASIC chip 40 in the MEMS microphone 120 is reduced, thereby helping to reduce the overall volume of the MEMS microphone 120, promote the miniaturization design of the MEMS microphone 120, and further help to realize the light and thin design of the electronic device 100. Compared with the existing MEMS microphone, the overall volume of the MEMS microphone 120 provided by the present application is reduced by 30%-40%. On the other hand, the installation area of the MEMS chip 30 and the ASIC chip 40 on the circuit board 10 is reduced, thereby saving the materials required for manufacturing the circuit board 10 and the housing 20, and helping to save the production cost of the MEMS microphone 120. Compared with the area of the circuit board 10 used in the existing MEMS microphone 120, the area of the circuit board 10 used in the MEMS microphone 120 provided by the present application is reduced by 50%.

[0096] Please refer to FIG. 5, which is a structure schematic diagram of the MEMS microphone 120 shown in FIG. 2 along the A-A line after being cut open in a second embodiment.

[0097] The MEMS microphone 120 described in the embodiment is different from the MEMS microphone 120 described in the first embodiment in that the first support layer 34 is arranged on the surface of the back plate 31 facing away from the support frame 32. The peripheral surface of the first support layer 34 is flush with the peripheral surface of the back plate 31. The diaphragm 35 is arranged on the surface of the first support layer 34 facing away from the back plate 31. The peripheral surface of the diaphragm 35 is flush with the peripheral surface of the first support layer 34. The second support layer 38 is arranged on the surface of the support frame 32 facing the circuit board 10. The peripheral surface of the second support layer 38 is flush with the peripheral surface of the support frame 32.

[0098] In the embodiment, the first wiring layer 33 is arranged on the surface of the back plate 31 facing away from the support frame 32, covers the first support layer 34, and is electrically connected between the back plate 31 and the ASIC chip 40, so that the back plate 31 and the ASIC chip 40 are electrically connected. Specifically, one end of the first wiring layer 33 away from the back plate 31 is exposed relative to the peripheral surface of the first support layer 34.

[0099] The second wiring layer 36 is arranged inside the diaphragm 35 and the first support layer 34, and is electrically connected between the diaphragm 35 and the ASIC chip 40, so that the diaphragm 35 and the ASIC chip 40 are electrically connected. Specifically, one end of the second wiring layer 36 away from the diaphragm 35 is exposed relative to the peripheral surface of the first support layer 34.

[0100] The third wiring layer 37 is arranged on one side of the support frame 32 facing the circuit board 10, covers the second support layer 38, and is electrically connected between the ASIC chip 40 and the circuit board 10, so that the ASIC chip 40 and the circuit board 10 are electrically connected, and thus the MEMS chip 30 can be electrically connected to the circuit board 10 through the ASIC chip 40. Specifically, one end of the third wiring layer 37 close to the ASIC chip 40 is exposed relative to the peripheral surface of the second support layer 38. Specifically, the third wiring layer 37 has two. The two third wiring layers 37 are arranged apart from each other. One end of each of the two third wiring layers 37 close to the ASIC chip 40 is exposed relative to the peripheral surface of the second support layer 38.

[0101] In the embodiment, one end of the fourth wiring layer 43 of the ASIC chip 40 away from the active layer 42 is exposed relative to the surface of the chip body 41 facing away from the active layer 42, and is electrically connected to the first wiring layer 33, so that the active layer 42 of the ASIC chip 40 and the back plate 31 are electrically connected.

[0102] The fifth wiring layer 44 of the ASIC chip 40 is arranged apart from the fourth wiring layer 43. One end of the fifth wiring layer 44 away from the active layer 42 is exposed relative to the surface of the chip body 41 facing away from the circuit board 10, and is electrically connected to the second wiring layer 36, so that the active layer 42 of the ASIC chip 40 and the diaphragm 35 are electrically connected.

[0103] The sixth wiring layer 45 of the ASIC chip 40 is located on the side of the fourth wiring layer 43 and the fifth wiring layer 44 facing the circuit board 10, and is spaced apart from the fourth wiring layer 43 and the fifth wiring layer 44. The end of the sixth wiring layer 45 away from the active layer 42 is exposed from the surface of the chip body 41 facing away from the active layer 42, and is electrically connected to the third wiring layer 37. For example, the sixth wiring layer 45 has two. Each of the sixth wiring layers 45 is electrically connected between the active layer 42 and one of the third wiring layers 37.

[0104] In this embodiment, by arranging the wiring inside the MEMS chip 30 and the ASIC chip 40, the signal transmission distance between the ASIC chip 40 and the MEMS chip 30, and between the ASIC chip 40 and the circuit board 10 is shortened, thereby helping to improve the signal transmission speed between the MEMS chip 30, the ASIC chip 40 and the circuit board 10. At the same time, the electrical connection between the MEMS chip 30 and the ASIC chip 40, and between the ASIC chip 40 and the circuit board 10 does not need to use gold wires required for wire bonding, thereby also helping to reduce the production cost of the MEMS microphone 120.

[0105] Please refer to FIG. 6, which is a structural schematic diagram of the MEMS microphone 120 shown in FIG. 2 along the A-A line after being cut open in a third embodiment.

[0106] The MEMS microphone 120 described in this embodiment is different from the MEMS microphone 120 described in the second embodiment in that the connecting layer 60 is a solder layer 62. That is, the connecting layer 60 is formed by using a soldering process. In this embodiment, the solder layer 62 includes a first solder portion 621, a second solder portion 622 and a third solder portion 623. The first solder portion 621, the second solder portion 622 and the third solder portion 623 are all arranged between the side surface of the MEMS chip 30 and the surface of the chip body 41 facing away from the active layer 42, and are spaced apart from each other. Among them, the first solder portion 621 and the second solder portion 622 are coated with a solder resist to avoid the first solder portion 621 and the second solder portion 622 from contacting each other, thereby preventing the MEMS chip 30 and the ASIC chip 40 from short circuiting.

[0107] Specifically, the first solder part 621 is electrically connected between the first trace layer 33 and the fourth trace layer 43, so as to electrically connect the first trace layer 33 and the active layer 42. The second solder part 622 is electrically connected between the second trace layer 36 and the fifth trace layer 44, so as to electrically connect the second trace layer 36 and the active layer 42. The third solder part 623 is electrically connected between the third trace layer 37 and the sixth trace layer 45, so as to electrically connect the third trace layer 37 and the active layer 42. Specifically, the third solder part 623 has two. Each of the third solder parts 623 is electrically connected between one of the third trace layers 37 and the sixth trace layer 45. In addition, the two third solder parts 623 are also coated with solder resist, so as to avoid the short circuit problem caused by the contact between the two third solder parts 623.

[0108] In this arrangement, on the one hand, the connection reliability between the MEMS chip 30 and the ASIC chip 40 can be enhanced, and on the other hand, the welding process is used to fix the MEMS chip 30 and the ASIC chip 40, which is low in cost and is conducive to reducing the production cost of the MEMS microphone 120.

[0109] Please refer to FIG. 7, which is a structural schematic diagram of the MEMS microphone 120 shown in FIG. 2 along the A-A line after being cut open in a fourth embodiment.

[0110] The MEMS microphone 120 described in the embodiment is different from the MEMS microphone 120 described in the third embodiment in that the first trace layer 33 is arranged inside the back plate 31. The end of the first trace layer 33 away from the back plate 31 is exposed relative to the peripheral surface of the back plate 31.

[0111] In this arrangement, the distance between the first trace layer 33 and the second trace layer 36 can be increased. When the first solder part 621 is electrically connected between the first trace layer 33 and the fourth trace layer 43, and the second solder part 622 is electrically connected between the second trace layer 36 and the fifth trace layer 44, the distance between the first solder part 621 and the second solder part 622 is also increased, so that the first solder part 621 and the second solder part 622 can be prevented from contacting each other, and thus the solder resist does not need to be additionally coated between the first solder part 621 and the second solder part 622, and the short circuit problem between the MEMS chip 30 and the ASIC chip 40 can be avoided.

[0112] Please refer to FIG. 8, which is a structural schematic diagram of the MEMS microphone 120 shown in FIG. 2 along the A-A line after being cut open in a fifth embodiment.

[0113] The MEMS microphone 120 described in the embodiment is different from the MEMS microphone 120 described in the third embodiment in that the active layer 42 and the chip body 41 are sequentially stacked on the surface of the connecting layer 60 away from the support frame 32. For example, the connecting layer 60 is a solder layer 62. In other embodiments, the connecting layer 60 can also be a wafer bonding layer 61 or an anisotropic conductive film (ACF) 63, etc.

[0114] In the embodiment, the first solder part 621, the second solder part 622 and the third solder part 623 of the solder layer 62 are all arranged between the side surface of the MEMS chip 30 and the surface of the active layer 42 away from the chip body 41, and are spaced apart from each other. Among them, the first solder part 621 and the second solder part 622 are coated with a solder resist to avoid mutual contact of the first solder part 621 and the second solder part 622, so as to prevent short circuit problem between the MEMS chip 30 and the ASIC chip 40.

[0115] Specifically, the first solder part 621 is electrically connected between the first trace layer 33 and the active layer 42. The second solder part 622 is electrically connected between the second trace layer 36 and the active layer 42. The third solder part 623 is electrically connected between the third trace layer 37 and the active layer 42. For example, the third solder part 623 has two. Each of the third solder parts 623 is electrically connected between one of the third trace layers 37 and the active layer 42. In addition, the two third solder parts 623 are also coated with a solder resist to avoid short circuit problem caused by mutual contact of the two adjacent third solder parts 623.

[0116] In the embodiment, by adopting the flip-chip welding mode, the active layer 42 of the ASIC chip 40 can be electrically connected with the MEMS chip 30 through the solder layer 62. At this time, the ASIC chip 40 does not need to be additionally provided with a trace inside, so as to simplify the production process flow of the MEMS microphone 120 and help to improve the production efficiency of the MEMS microphone 120.

[0117] Please refer to FIG. 9, which is a structural schematic diagram of the MEMS microphone 120 along the A-A line after being cut in the sixth embodiment.

[0118] The MEMS microphone 120 described in the embodiment is different from the MEMS microphone 120 described in the third embodiment in that the connection layer 60 is an anisotropic conductive film (ACF) 63. The anisotropic conductive film 63 includes a first conductive part 631 and a second conductive part 632. The first conductive part 631 is electrically connected between the first trace layer 33, the second trace layer 36 and the active layer 42. The second conductive part 632 is located on the side of the first conductive part 631 facing the circuit board 10 and is electrically connected between the third trace layer 37 and the active layer 42. For example, the second conductive part 632 is fixedly connected to the first conductive part 631. In other embodiments, the second conductive part 632 can also be arranged separately from the first conductive part 631.

[0119] It can be understood that the anisotropic conductive film 63 has conductive particles inside. The conductive particles can transmit the electrical signal of the change in capacitance between the back plate 31 and the diaphragm 35 to the ASIC chip 40, so as to realize electrical connection between the MEMS chip 30 and the ASIC chip 40. It should be noted that the conductive particles in the anisotropic conductive film 63 only move in the thickness direction inside the anisotropic conductive film 63, so as to ensure that the anisotropic conductive film 63 can only conduct electricity in the thickness direction, thereby ensuring that the circuit formed between the first trace layer 33 and the active layer 42 and the circuit formed between the second trace layer 36 and the active layer 42 are not staggered, and preventing short circuit problems between the MEMS chip 30 and the ASIC chip 40.

[0120] In addition, the fixing member 50 of the MEMS microphone 120 is also an anisotropic conductive film, so as to realize electrical connection between the MEMS chip 30 and the circuit board 10 through the ASIC chip 40. In this arrangement, the anisotropic conductive film 63 is directly bonded between the MEMS chip 30 and the ASIC chip 40 and between the MEMS chip 30 and the circuit board 10, so as to realize electrical connection between the MEMS chip 30 and the ASIC chip 40 and between the ASIC chip and the circuit board 10. This is simple to operate and is conducive to improving the production efficiency of the MEMS microphone 120.

[0121] Please refer to FIG. 10, which is a structure diagram of the MEMS microphone 120 along the A-A line after being cut open in the seventh embodiment.

[0122] The MEMS microphone 120 in the embodiment is different from the MEMS microphone 120 in the third embodiment in that the connecting layer 60 is a die attach film (DAF) 64. The die attach film 64 is attached between the support frame 32 and the chip body 41 of the MEMS chip 30, so as to fix the MEMS chip 30 and the ASIC chip 40.

[0123] In the embodiment, the MEMS chip 30 and the ASIC chip 40, and the ASIC chip 40 and the circuit board 10 are electrically connected by wire bonding. Specifically, the MEMS microphone 120 further includes a first wire 70, a second wire 80, and a third wire 90. The first wire 70 is electrically connected between the first trace layer 33 and the active layer 42, so as to electrically connect the back plate 31 and the ASIC chip 40. The second wire 80 is electrically connected between the second trace layer 36 and the active layer 42, so as to electrically connect the diaphragm 35 and the ASIC chip 40. The third wire 90 is electrically connected between the third trace layer 37 and the active layer 42, so as to electrically connect the ASIC chip 40 and the circuit board 10, thereby electrically connecting the MEMS chip 30, the ASIC chip 40, and the circuit board 10. Specifically, the third wire 90 has two wires. Each of the third wires 90 is electrically connected between the first third trace layer 37 and the active layer 42.

[0124] In this arrangement, on the one hand, the wire bonding is used to electrically connect the MEMS chip 30 and the ASIC chip 40, and the ASIC chip 40 and the circuit board 10, so that the connection between the MEMS chip 30 and the ASIC chip 40 is reliable. On the other hand, the wire bonding process is less costly than the wafer bonding process, which is also conducive to reducing the production cost of the MEMS microphone 120. At the same time, the ASIC chip 40 does not need to be additionally provided with a trace layer, which is helpful to simplify the production process of the MEMS microphone 120 and improve the production efficiency of the MEMS microphone 120.

[0125] Please refer to FIGS. 11-23. The application further provides a method for manufacturing the first MEMS microphone 120.

[0126] In step S1, a microphone intermediate body 121 and a circuit board are provided. The microphone intermediate body 121 includes a silicon substrate 121a and an ASIC chip 40. The silicon substrate 121a includes a support frame intermediate body 32a and a back plate 31, and the back plate 31 is fixedly connected to the upper surface of the support frame intermediate body 32a. The ASIC chip 40 is mounted on the side surface of the silicon substrate 121a and is electrically connected to the back plate 31. The circuit board is provided with a sound hole, and the sound hole penetrates the circuit board along the thickness direction of the circuit board.

[0127] In this embodiment, the above step S1 can be completed by steps S11 to S15.

[0128] In step S11, the ASIC chip 40 is mounted on the side surface of the silicon substrate 121a to obtain a microphone preform (not shown in the figure). For example, a wafer bonding process can be used to mount the ASIC chip 40 on the side surface of the silicon substrate 121a. In this process, a polishing process such as a chemical mechanical polishing (CMP) process can be used to planarize the surface of the silicon substrate 121a and the surface of the ASIC chip 40 to ensure that the surface of the silicon substrate 121a and the ASIC chip 40 is well connected.

[0129] In step S12, the silicon substrate 121a is etched to form a plurality of etching grooves 121c. The plurality of etching grooves 121c are arranged at intervals. The openings of the plurality of etching grooves 121c are located on the upper surface of the silicon substrate 121a, and the plurality of etching grooves 121c are recessed from the upper surface of the silicon substrate 121a to the lower surface of the silicon substrate 121a. The distance between the centers of the openings of two adjacent etching grooves 121c is between 0.1 μm and 1 μm. The width of the opening of each etching groove 121c is between 0.1 μm and 1 μm. The depth of each etching groove 121c is between 1 μm and 10 μm.

[0130] In step S13, the microphone preform is annealed to form a cavity 121d in the silicon substrate 121a to obtain a back plate intermediate body 31a and a support frame intermediate body 32a. The back plate intermediate body 31a is fixedly connected to the upper surface of the support frame intermediate body 32a. The thickness of the back plate intermediate body 31a is between 1 μm and 3 μm to ensure that the structure of the back plate 31 formed in the subsequent step has a large structural strength and meets the production requirements of the product. It should be noted that if the thickness of the back plate 31 to be formed in the subsequent step is greater than 3 μm, an epitaxial process can be applied to the upper surface of the silicon substrate 121a to increase the thickness of the back plate intermediate body 31a.

[0131] In the above step S13, the microphone preform can be annealed by a VENSEN process. The reaction atmosphere used in the VENSEN process is hydrogen, and the process temperature is between 1000°C and 1200°C. In this process, silicon atoms diffuse and fill the plurality of etching grooves 121c and close the openings of the plurality of etching grooves 121c, thereby forming a cavity 121d in the silicon substrate 121a.

[0132] Step S14, a first wiring layer 33 is formed on the upper surface of the backplate intermediate body 31a and the upper surface of the ASIC chip 40. The first wiring layer 33 is electrically connected between the backplate intermediate body 31a and the ASIC chip 40. For example, the first wiring layer 33 can be formed on the upper surface of the backplate intermediate body 31a and the upper surface of the ASIC chip 40 by using a damascene process.

[0133] In the above step S15, photoresist can be first coated on the upper surface of the backplate intermediate body 31a and the upper surface of the ASIC chip 40, and then the region where the first wiring layer 33 is to be formed is formed by using exposure, development, lithography and other processes. Then, the first wiring layer 33 is formed in the region where the first wiring layer 33 is to be formed by using electroplating. Finally, the photoresist is removed to form the patterned first wiring layer 33.

[0134] Step S15, the backplate intermediate body 31a is etched to form a plurality of through holes 311, thereby obtaining the backplate 31. The plurality of through holes 311 are arranged at intervals and each penetrates the backplate 31 along the thickness direction of the backplate 31 and communicates with the cavity 121d.

[0135] In the above step S15, the upper surface of the backplate 31 and the upper surface of the ASIC chip 40 are provided with the first wiring layer 33. The first wiring layer 33 is electrically connected between the backplate 31 and the ASIC chip 40.

[0136] Step S2, a first sacrificial layer 34a is formed on the upper surface of the silicon substrate 121a and the upper surface of the ASIC chip 40. The first sacrificial layer 34a covers the first wiring layer 33. For example, the first sacrificial layer 34a can be formed on the upper surface of the silicon substrate 121a and the upper surface of the ASIC chip 40 by using a vapor deposition method. In other embodiments, the first sacrificial layer 34a can also be formed on the upper surface of the silicon substrate 121a and the upper surface of the ASIC chip 40 by using a thermal oxidation method.

[0137] In the above step S2, part of the first sacrificial layer 34a is filled in the cavity 121d and the plurality of through holes 311, and the other part is arranged on the upper surface of the backplate 31 and the upper surface of the ASIC chip 40. The part of the first sacrificial layer 34a arranged on the upper surface of the backplate 31 and the upper surface of the ASIC chip 40 has a thickness of 1 μm to 4 μm.

[0138] Step S3, a first electrical connection part 361 is formed in the first sacrificial layer 34a. The first electrical connection part 361 is arranged at an interval from the first wiring layer 33 and is electrically connected to the ASIC chip 40. For example, the first electrical connection part 361 can be formed in the first sacrificial layer 34a by using a damascene process.

[0139] Step S4, a diaphragm 35 is formed on the surface of the first sacrificial layer 34a away from the silicon substrate 121a and the ASIC chip 40. The diaphragm 35 is electrically connected to the ASIC chip 40.

[0140] Step S5, a second electrical connection part 362 is formed in the diaphragm 35 and the first sacrificial layer 34a, the second electrical connection part 362 is electrically connected to the first electrical connection part 361 and the diaphragm 35, and a second trace layer 36 is obtained. The second trace layer 36 is electrically connected between the diaphragm 35 and the ASIC chip 40. For example, the second electrical connection part 362 can be formed in the diaphragm 35 and the first sacrificial layer 34a by using a through-silicon-via (TSV) technology. The material of the second electrical connection part 362 can be copper, tungsten, polysilicon or the like.

[0141] Step S6, a third electrical connection part 371 is formed on the lower surface of the silicon substrate 121a and the lower surface of the ASIC chip 40. The third electrical connection part 371 is electrically connected to the ASIC chip 40. For example, the third electrical connection part 371 can be formed on the lower surface of the silicon substrate 121a and the lower surface of the ASIC chip 40 by using a damascene process.

[0142] In the above step S6, photoresist can be first coated on the lower surface of the silicon substrate 121a and the lower surface of the ASIC chip 40, then the area where the third electrical connection part 371 is to be formed is formed by using exposure, development and lithography, and then the third electrical connection part 371 is formed in the area by using electroplating, and finally the photoresist is removed to form the patterned third electrical connection part 371.

[0143] Step S7, a second sacrificial layer 38a is formed on the lower surface of the silicon substrate 121a and the lower surface of the ASIC chip 40. The second sacrificial layer 38a covers the third electrical connection part 371.

[0144] Step S8, a fourth electrical connection part 372 is formed in the second sacrificial layer 38a, the fourth electrical connection part 372 is electrically connected to the third electrical connection part 371, and a third trace layer 37 is obtained. The third trace layer 37 is electrically connected to the ASIC chip 40. For example, the fourth electrical connection part 372 can be formed in the second sacrificial layer 38a by using a through-silicon-via technology.

[0145] Step S9, the second sacrificial layer 38a, the silicon substrate 121a and the first sacrificial layer 34a are etched from the lower surface of the silicon substrate 121a to the upper surface of the silicon substrate 121a, and a second support layer 38, a support frame 32 and a first support layer 34 are formed, and a MEMS chip 30 is obtained. In the above step S9, the silicon substrate 121a is etched and polished to form an acoustic cavity 30a of the MEMS chip 30.

[0146] In step S10, the MEMS chip 30 and the ASIC chip 40 are mounted to the circuit board to obtain the MEMS microphone 120. The MEMS chip 30 covers the sound hole and is electrically connected to the circuit board. The sound cavity 30a of the MEMS chip 30 is in communication with the sound hole. The ASIC chip 40 is electrically connected to the circuit board. In step S10, the housing is also fixedly mounted to the circuit board, and the housing covers the MEMS chip 30 and the ASIC chip 40.

[0147] Please refer to FIGS. 24-34. The present application also provides a second method for manufacturing the MEMS microphone 120. The method is used to manufacture the MEMS microphone 120 in the second embodiment.

[0148] In step S1', the MEMS chip 30, the ASIC chip, and the circuit board are provided. The circuit board is provided with a sound hole penetrating through the circuit board along the thickness direction of the circuit board. The MEMS chip 30 includes a back plate 31, a support frame 32, a first support layer 34, a diaphragm 35, a first wiring layer 33, a second wiring layer 36, and a third wiring layer 37. The back plate 31 is fixedly connected to one side of the support frame 32 away from the circuit board. The first support layer 34 is arranged on the surface of the back plate 31 away from the support frame 32. The diaphragm 35 is arranged on the surface of the first support layer 34 away from the back plate 31. The first wiring layer 33 and the second wiring layer 36 are both arranged on the side of the back plate 31 away from the support frame 32. The second wiring layer 36 is arranged spaced apart from the first wiring layer 33. The third wiring layer 37 is arranged on the side of the support frame 32 facing the circuit board. The ASIC chip includes a chip body and an active layer, and the active layer is arranged in a stacked manner with the chip body.

[0149] In step S1', steps S101'-S112' are further included.

[0150] In step S101', the silicon substrate 121a is etched to form a plurality of etching grooves 121c. The plurality of etching grooves 121c are arranged spaced apart from each other. The openings of the plurality of etching grooves 121c are located on the upper surface of the silicon substrate 121a, and the plurality of etching grooves 121c are recessed from the upper surface of the silicon substrate 121a to the lower surface of the silicon substrate 121a.

[0151] In step S102', the silicon substrate 121a is annealed to form a cavity 121d in the silicon substrate 121a, thereby obtaining a back plate intermediate body 31a and a support frame intermediate body 32a. The back plate intermediate body 31a is fixedly connected to the upper surface of the support frame intermediate body 32a.

[0152] In step S103', the first wiring layer 33 is formed on the upper surface of the back plate intermediate body 31a.

[0153] In some other embodiments, the first wiring layer 33 can also be formed in the back plate intermediate body 31a in the step S103'. In this case, the first wiring layer 33 is exposed from the circumferential surface of the first sacrificial layer 34a away from one end of the back plate 31.

[0154] In the step S104', the back plate intermediate body 31a is etched to form a plurality of through holes 311, and the back plate 31 is obtained. The plurality of through holes 311 are arranged at intervals and each penetrates the back plate 31 along the thickness direction of the back plate 31 and communicates with the cavity 121d.

[0155] In the step S104', the first wiring layer 33 is arranged on the upper surface of the back plate 31. The first wiring layer 33 is electrically connected to the back plate 31.

[0156] In the step S105', the first sacrificial layer 34a is formed on the upper surface of the silicon substrate 121a. The first sacrificial layer 34a covers the first wiring layer 33.

[0157] In the step S105', part of the first sacrificial layer 34a is filled in the cavity 121d and the plurality of through holes 311, and the other part is arranged on the upper surface of the back plate 31.

[0158] In the step S106', the first electrical connection part 361 is formed in the first sacrificial layer 34a. The first electrical connection part 361 is arranged at an interval from the first wiring layer 33.

[0159] In the step S107', the diaphragm 35 is formed on the surface of the first sacrificial layer 34a away from the silicon substrate 121a.

[0160] In the step S108', the second electrical connection part 362 is formed in the diaphragm 35 and the first sacrificial layer 34a. The second electrical connection part 362 is electrically connected to the first electrical connection part 361 and the diaphragm 35, and the second wiring layer 36 is obtained. The second wiring layer 36 is electrically connected to the diaphragm 35.

[0161] In the step S109', the third electrical connection part 371 is formed on the lower surface of the silicon substrate 121a.

[0162] In the step S110', the second sacrificial layer 38a is formed on the lower surface of the silicon substrate 121a. The second sacrificial layer 38a covers the third electrical connection part 371.

[0163] In the step S111', the fourth electrical connection part 372 is formed in the second sacrificial layer 38a. The fourth electrical connection part 372 is electrically connected to the third electrical connection part 371, and the third wiring layer 37 is obtained.

[0164] Step S112', etching the second sacrificial layer 38a, the silicon substrate 121a and the first sacrificial layer 34a from the lower surface of the silicon substrate 121a to the upper surface of the silicon substrate 121a, to form the second support layer 38, the support frame 32 and the first support layer 34, to obtain the MEMS chip 30.

[0165] Step S2', mounting the ASIC chip 40 to the side surface of the MEMS chip 30. Wherein, the ASIC chip 40 is electrically connected with the MEMS chip 30.

[0166] The above step S2' can be completed by various different embodiments. For example, in a first embodiment, the surface of the chip body away from the active layer is wafer bonded to the side surface of the MEMS chip 30 to form a connection layer. In a second embodiment, the surface of the chip body away from the active layer is soldered to the side surface of the MEMS chip 30 to form a first solder part, a second solder part and a third solder part, to obtain a connection layer.

[0167] In a third embodiment, step S2' can be completed by the following steps S21' to S23'.

[0168] Step S21', providing an anisotropic conductive adhesive film.

[0169] Step S22', fixing and mounting the anisotropic conductive adhesive film to the side surface of the MEMS chip 30.

[0170] Step S23', mounting the ASIC chip to the surface of the anisotropic conductive adhesive film away from the MEMS chip 30.

[0171] In a third embodiment, step S2' can be completed by the following steps S21" to S26".

[0172] Step S21", providing a chip bonding film, a first lead wire, a second lead wire and a third lead wire.

[0173] Step S22", fixing and mounting the chip bonding film to the outer circumferential surface of the support frame 32.

[0174] Step S23", mounting the ASIC chip to the surface of the chip bonding film away from the support frame 32. Wherein, the chip body and the active layer are sequentially stacked on the surface of the chip bonding film away from the support frame 32.

[0175] Step S24", electrically connecting the first lead wire between the first trace layer 33 and the active layer.

[0176] Step S25", electrically connecting the second lead wire between the second trace layer 36 and the active layer.

[0177] Step S26", electrically connecting the third wire with the third trace layer 37 and the active layer.

[0178] Step S3', mounting the MEMS chip 30 to the circuit board to obtain the MEMS microphone 120. The MEMS chip 30 covers the sound hole and is electrically connected with the circuit board. The sound cavity 30a of the MEMS chip 30 is in communication with the sound hole, and the ASIC chip is electrically connected with the circuit board. In the above step S3', it further includes: fixedly mounting the shell to the circuit board, and covering the shell on the MEMS chip 30 and the ASIC chip 40.

[0179] The above is only part of the embodiments and implementation manners of the present application, and the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A MEMS microphone, characterized in that: The invention comprises a circuit board, a MEMS chip and an ASIC chip. The circuit board is provided with a sound hole, which penetrates the circuit board along the thickness direction of the circuit board. The MEMS chip is mounted on the circuit board, covers the sound hole, and is electrically connected to the circuit board. The sound cavity of the MEMS chip is connected to the sound hole. The ASIC chip is mounted on the side of the MEMS chip and is electrically connected to both the MEMS chip and the circuit board.

2. The MEMS microphone according to claim 1, wherein: The ASIC chip includes a chip body and an active layer, and the active layer and the chip body are stacked on the side of the MEMS chip.

3. The MEMS microphone according to claim 2, wherein: The MEMS chip includes a back plate, a support frame, a first support layer, a diaphragm, and a second support layer. The back plate is fixedly connected to the side of the support frame away from the circuit board. The first support layer is provided on the surface of the back plate away from the support frame. The diaphragm is provided on the surface of the first support layer away from the back plate. The second support layer is provided on the surface of the support frame away from the back plate. The active layer and the chip body are stacked on the outer peripheral surface of the support frame.

4. The MEMS microphone according to claim 3, wherein: The first supporting layer is further provided on a surface of the ASIC chip facing away from the circuit board, and the diaphragm is further provided on a surface of the first supporting layer facing away from the ASIC chip.

5. The MEMS microphone according to claim 3 or 4, characterized in that: The MEMS chip also includes a first routing layer, a second routing layer and a third routing layer. The first routing layer and the second routing layer are both arranged on the side of the back plate facing away from the support frame. The first routing layer is electrically connected between the back plate and the ASIC chip. The second routing layer is spaced apart from the first routing layer and is electrically connected between the diaphragm and the ASIC chip. The third routing layer is arranged on the side of the support frame facing the circuit board and is electrically connected between the ASIC chip and the circuit board.

6. The MEMS microphone according to claim 5, characterized in that The MEMS microphone further includes a connection layer connected between the outer peripheral surface of the support frame and the ASIC chip.

7. The MEMS microphone according to claim 6, wherein: The connection layer is a wafer bonding layer and electrically connects the first routing layer, the second routing layer, the third routing layer and the active layer.

8. The MEMS microphone according to claim 6, wherein: The connecting layer is a solder layer, and the connecting layer includes a first solder portion, a second solder portion and a third solder portion. The first solder portion is electrically connected between the first routing layer and the active layer, the second solder portion is spaced apart from the first solder portion, and is electrically connected between the second routing layer and the active layer, and the third solder portion is located on the side of the first solder portion and the second solder portion facing the circuit board, and is spaced apart from the first solder portion and the second solder portion, and is electrically connected between the third routing layer and the active layer.

9. The MEMS microphone according to claim 6, wherein: The connecting layer is an anisotropic conductive film, which includes a first conductive part and a second conductive part. The first conductive part is electrically connected between the first routing layer, the second routing layer and the active layer. The second conductive part is located on the side of the first conductive part facing the circuit board, and the second conductive part is electrically connected between the third routing layer and the active layer.

10. The MEMS microphone according to any one of claims 6 to 9, characterized in that The chip body and the active layer are sequentially stacked on a surface of the connection layer facing away from the support frame.

11. The MEMS microphone according to claim 10, wherein: The ASIC chip further includes a fourth routing layer, a fifth routing layer, and a sixth routing layer. The fourth routing layer is electrically connected between the active layer and the first routing layer. The fifth routing layer is spaced apart from the fourth routing layer and is electrically connected between the active layer and the second routing layer. The sixth routing layer is located on a side of the fourth routing layer and the fifth routing layer facing the circuit board, is spaced apart from the fourth routing layer and the fifth routing layer, and is electrically connected between the active layer and the third routing layer.

12. The MEMS microphone according to claim 10, wherein: The connecting layer is a chip bonding film, and the chip bonding film is bonded between the support frame and the chip body; The MEMS microphone further includes a first wire, a second wire, and a third wire. The first wire is electrically connected between the first routing layer and the active layer, the second wire is electrically connected between the second routing layer and the active layer, and the third wire is electrically connected between the third routing layer and the active layer.

13. The MEMS microphone according to any one of claims 6 to 9, characterized in that The active layer and the chip body are sequentially stacked on a surface of the connection layer facing away from the support frame.

14. The MEMS microphone according to claim 3, wherein: The back plate is provided with a plurality of through holes, which penetrate the back plate along the thickness direction of the back plate, are spaced apart from each other, and are all connected to the sound cavity of the MEMS.

15. The MEMS microphone according to claim 1, wherein The MEMS microphone further includes a housing, which is fixedly mounted on the circuit board and covers the MEMS chip and the ASIC chip.

16. An electronic device, characterized in that: The method comprises a processor and the MEMS microphone according to any one of claims 1 to 15, wherein the processor is electrically connected to the MEMS microphone.

17. A method for preparing a MEMS microphone, characterized in that: include: A microphone intermediate body and a circuit board are provided. The microphone intermediate body includes a silicon substrate and an ASIC chip. The silicon substrate includes a support frame intermediate body and a back plate. The back plate is fixedly connected to the upper surface of the support frame intermediate body. The ASIC chip is mounted on the side of the silicon substrate and is electrically connected to the back plate. The circuit board is provided with an acoustic hole, which penetrates the circuit board along the thickness direction of the circuit board. forming a first sacrificial layer on the upper surface of the silicon substrate and the upper surface of the ASIC chip; forming a diaphragm on a surface of the first sacrificial layer away from the silicon substrate and the ASIC chip, wherein the diaphragm is electrically connected to the ASIC chip; forming a second sacrificial layer on the lower surface of the silicon substrate and the lower surface of the ASIC chip; Etching the second sacrificial layer, the silicon substrate, and the first sacrificial layer from the lower surface of the silicon substrate toward the upper surface of the silicon substrate to form a second supporting layer, a supporting frame, and a first supporting layer to obtain a MEMS chip; The MEMS chip and the ASIC chip are mounted on the circuit board to obtain a MEMS microphone, wherein the MEMS chip covers the sound hole and is electrically connected to the circuit board, the sound cavity of the MEMS chip is connected to the sound hole, and the ASIC chip is electrically connected to the circuit board.

18. The method for preparing a MEMS microphone according to claim 17, wherein: The steps of providing a microphone intermediate body and a circuit board include: forming a first wiring layer on the upper surface of the back plate and the upper surface of the ASIC chip, wherein the first wiring layer is electrically connected between the back plate and the ASIC chip; In the step of forming a first sacrificial layer on the upper surface of the silicon substrate and the upper surface of the ASIC chip, the first sacrificial layer covers the first routing layer.

19. The method for preparing a MEMS microphone according to claim 18, wherein: After the step of forming a first sacrificial layer on the upper surface of the silicon substrate and the upper surface of the ASIC chip, and before the step of forming a diaphragm on a surface of the first sacrificial layer facing away from the silicon substrate and the ASIC chip, the method for preparing the MEMS microphone further includes: forming a first electrical connection portion in the first sacrificial layer, wherein the first electrical connection portion is spaced apart from the first wiring layer and is electrically connected to the ASIC chip; After forming a diaphragm on a surface of the first sacrificial layer facing away from the silicon substrate and the ASIC chip, and before forming a second sacrificial layer on the lower surface of the silicon substrate and the lower surface of the ASIC chip, the method for preparing the MEMS microphone further includes: A second electrical connection portion is formed in the diaphragm and the first sacrificial layer. The second electrical connection portion is electrically connected to the first electrical connection portion and the diaphragm to obtain a second routing layer. The second routing layer is electrically connected between the diaphragm and the ASIC chip.

20. The method for preparing a MEMS microphone according to claim 17, wherein: After forming a diaphragm on a surface of the first sacrificial layer facing away from the silicon substrate and the ASIC chip, and before forming a second sacrificial layer on the lower surface of the silicon substrate and the lower surface of the ASIC chip, the method for preparing the MEMS microphone further includes: forming a third electrical connection portion on the lower surface of the silicon substrate and the lower surface of the ASIC chip, wherein the third electrical connection portion is electrically connected to the ASIC chip; In the step of forming a second sacrificial layer on the lower surface of the silicon substrate and the lower surface of the ASIC chip, the second sacrificial layer covers the third electrical connection portion; After the step of forming a second sacrificial layer on the lower surface of the silicon substrate and the lower surface of the ASIC chip, and before the step of etching the second sacrificial layer, the silicon substrate, and the first sacrificial layer from the lower surface of the silicon substrate toward the upper surface of the silicon substrate, the method for preparing the MEMS microphone further includes: A fourth electrical connection portion is formed in the second sacrificial layer, the fourth electrical connection portion is electrically connected to the third electrical connection portion to obtain a third routing layer, and the third routing layer is electrically connected to the ASIC chip.

21. The method for preparing a MEMS microphone according to claim 17, wherein: The steps of providing a microphone intermediate body and a circuit board include: Mounting the ASIC chip on the side of the silicon substrate to obtain a microphone preform; Etching the silicon substrate to form a plurality of etching grooves, wherein the plurality of etching grooves are spaced apart from each other, and openings of the plurality of etching grooves are all located on the upper surface of the silicon substrate; Annealing the microphone preform to form a cavity inside the silicon substrate to obtain a back plate intermediate and the support frame intermediate, wherein the back plate intermediate is fixedly connected to the upper surface of the support frame intermediate; The back plate intermediate is etched to form a plurality of through holes to obtain the back plate, wherein the plurality of through holes are arranged at intervals, all pass through the back plate along the thickness direction of the back plate, and all communicate with the cavity.

22. The method for preparing a MEMS microphone according to claim 17, wherein: The step of mounting the MEMS chip on the circuit board to obtain a MEMS microphone includes: The housing is fixedly mounted on the circuit board, and the housing covers the MEMS chip and the ASIC chip.

23. A method for preparing a MEMS microphone, characterized in that: include: A MEMS chip, an ASIC chip, and a circuit board are provided, wherein the circuit board is provided with an acoustic hole, and the acoustic hole penetrates the circuit board along the thickness direction of the circuit board; Mounting the ASIC chip on a side of the MEMS chip, wherein the ASIC chip is electrically connected to the MEMS chip; The MEMS chip is mounted on a circuit board to obtain a MEMS microphone, wherein the MEMS chip covers the sound hole and is electrically connected to the circuit board, the sound cavity of the MEMS chip is connected to the sound hole, and the ASIC chip is electrically connected to the circuit board.

24. The method for preparing a MEMS microphone according to claim 23, wherein: The ASIC chip includes a chip body and an active layer, wherein the active layer and the chip body are stacked. The step of mounting the ASIC chip on the side of the MEMS chip includes: Wafer bonding is performed on the surface of the chip body facing away from the active layer and the side surface of the MEMS chip to form a connection layer.

25. The method for preparing a MEMS microphone according to claim 23, wherein: The ASIC chip includes a chip body and an active layer, wherein the active layer and the chip body are stacked. The step of mounting the ASIC chip on the side of the MEMS chip includes: The surface of the chip body facing away from the active layer is welded to the side surface of the MEMS chip to form a first solder portion, a second solder portion and a third solder portion to obtain a connection layer.

26. The method for preparing a MEMS microphone according to claim 23, wherein: The step of mounting the ASIC chip on the side of the MEMS chip includes: Provide anisotropic conductive film; The anisotropic conductive film is fixedly mounted on the side of the MEMS chip; The ASIC chip is mounted on the surface of the anisotropic conductive adhesive film facing away from the MEMS chip.

27. The method for preparing a MEMS microphone according to claim 23, wherein: The MEMS chip includes a back plate, a support frame, a first support layer, a diaphragm, a first routing layer, a second routing layer and a third routing layer. The back plate is fixedly connected to the side of the support frame away from the circuit board. The first support layer is provided on the surface of the back plate away from the support frame. The diaphragm is provided on the surface of the first support layer away from the back plate. The first routing layer and the second routing layer are both provided on the side of the back plate away from the support frame. The second routing layer is spaced apart from the first routing layer. The third routing layer is provided on the side of the support frame facing the circuit board. The ASIC chip includes a chip body and an active layer. The active layer is stacked with the chip body. The step of mounting the ASIC chip on the side of the MEMS chip includes: providing a die attach film, a first wire, a second wire, and a third wire; Fixing the die bonding film to the outer peripheral surface of the support frame; Mounting the ASIC chip on the surface of the die bonding film facing away from the support frame, with the chip body and the active layer sequentially stacked on the surface of the die bonding film facing away from the support frame; electrically connecting the first wire between the first wiring layer and the active layer; electrically connecting the second wire between the second wiring layer and the active layer; The third conductive line is electrically connected between the third wiring layer and the active layer.

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