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] This application claims priority to the Chinese patent application filed with the China Patent Office on November 28, 2023, with application number 202311602168.5 and application name “MEMS microphone, preparation method thereof and electronic device”, the entire contents of which are incorporated by reference into this application. Technical Field

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

[0003] MEMS (Micro-Electro-Mechanical Systems) microphones are widely used in various electronic devices due to their advantages such as high signal-to-noise ratio, good stability and low power consumption. In existing MEMS microphones, the interaction between the MEMS chip and the ASIC (Application Specific Integrated Circuit) chip can convert sound signals into electrical signals, thereby enabling the MEMS microphone to achieve the sound reception function. However, the layout of the existing MEMS chip and ASIC chip is unreasonable, resulting in a large overall size of the MEMS microphone, making it difficult to achieve miniaturization design of the MEMS microphone, which is not conducive to the realization of lightweight and thin design of electronic devices.

[0004] Summary of the Invention

[0005] The present application provides a MEMS microphone, a preparation 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 achieve a lightweight and thin design of the electronic device.

[0006] In a first aspect, the present application provides a MEMS microphone comprising a circuit board, a MEMS chip, and an ASIC chip. The circuit board is provided with an acoustic hole, the acoustic hole penetrating the circuit board along the thickness direction of the circuit board. The MEMS chip is mounted on the circuit board, covers the acoustic hole, and is electrically connected to the circuit board. The sound cavity of the MEMS chip is in communication with the acoustic 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. The MEMS microphone provided by the present application, by fixing the ASIC chip to the side of the MEMS chip, can make the assembled structure of the MEMS chip and the ASIC chip more compact, thereby reducing the installation space occupied by the MEMS chip and the ASIC chip in the MEMS microphone, thereby facilitating a reduction in the overall volume of the MEMS microphone and promoting a miniaturized 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, thereby saving the materials required for making the circuit board and the housing, which is conducive to saving the production cost of the MEMS microphone.

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

[0008] In one possible embodiment, 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 facing away from the circuit board. The first support layer is provided on the surface of the back plate facing away from the support frame. The diaphragm is provided on the surface of the first support layer facing away from the back plate. The second support layer is provided on the surface of the support frame facing away from the back plate. The active layer and the chip body are stacked on the outer peripheral surface of the support frame. Under this arrangement, the diaphragm is spaced apart from the back plate by the first support layer, so that the diaphragm and the back plate together form a capacitor structure. When the diaphragm is subjected to the sound pressure of the sound signal, it deforms, and the capacitance value between the diaphragm and the back plate changes. The ASIC chip can detect the capacitance change between the diaphragm and the back plate and convert it into an electrical signal output, thereby completing the sound-to-electricity conversion and enabling the MEMS microphone to achieve the sound collection function.

[0009] In one possible embodiment, the first support layer is further disposed on the surface of the ASIC chip facing away from the circuit board, and the diaphragm is further disposed on the surface of the first support layer facing away from the ASIC chip. In this arrangement, the ASIC chip can support the diaphragm, significantly increasing the effective area of ​​the diaphragm, thereby accelerating the diaphragm's response to sound signals and reducing the diaphragm's acoustic conversion loss ratio, thereby improving the acoustic efficiency and acoustic performance of the MEMS microphone.

[0010] In one possible embodiment, the MEMS chip further 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 provided 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 provided on the side of the support frame facing the circuit board and is electrically connected between the ASIC chip and the circuit board. In this embodiment, by providing the first routing layer and the second routing layer, the diaphragm and the back plate can be electrically connected to the ASIC chip respectively, so that the ASIC chip can detect the change in capacitance between the diaphragm and the back plate, thereby converting sound signals into electrical signals, and further realizing the sound collection function of the MEMS microphone. By providing the third routing layer and electrically connecting the end of the third routing layer away from the ASIC chip to the circuit board, the ASIC chip and the circuit board are electrically connected, so that the MEMS chip can be electrically connected to the circuit board through the ASIC chip.

[0011] In one possible embodiment, the MEMS microphone further includes a connection layer connected between the outer circumference of the support frame and the ASIC chip. The connection layer formed between the outer circumference of the support frame and the ASIC chip enables electrical connection between the MEMS chip and the ASIC chip.

[0012] In one possible implementation, 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. In this embodiment, a wafer bonding process is used to form the wafer bonding layer, so that the first routing layer, the second routing layer, and the third routing layer are electrically connected to the active layer through the wafer bonding layer. Under this setting, 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, there is no need to use the gold wire required for wire bonding to achieve electrical connection between the MEMS chip and the ASIC chip, which is also conducive to reducing the production cost of the MEMS microphone.

[0013] In one possible embodiment, the connection layer is a solder layer, comprising 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 electrically connected between the second routing layer and the active layer. The third solder portion is located on the side of the first and second solder portions facing the circuit board, spaced apart from both the first and second solder portions, and electrically connected between the third routing layer and the active layer. This arrangement, on the one hand, enhances the connection reliability between the MEMS chip and the ASIC chip. On the other hand, the use of a soldering process to secure the MEMS chip and the ASIC chip is relatively inexpensive, which helps reduce the production cost of the MEMS microphone.

[0014] In one possible embodiment, the connection layer is an anisotropic conductive adhesive film comprising a first conductive portion and a second conductive portion. The first conductive portion is electrically connected between the first and second trace layers, and the active layer. The second conductive portion is located on the side of the first conductive portion facing the circuit board and is electrically connected between the third trace layer and the active layer. This arrangement allows electrical connection between the MEMS chip and the ASIC chip to be achieved simply by bonding the anisotropic conductive adhesive film between them. This simplifies operation and improves the production efficiency of MEMS microphones.

[0015] In one possible embodiment, the chip body and the active layer are sequentially stacked on a surface of the connection layer facing away from the support frame. Exemplarily, 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 electrically connected between the active layer and the second routing layer. The sixth routing layer is located on the side of the fourth and fifth routing layers facing the circuit board, spaced apart from both the fourth and fifth routing layers, and electrically connected between the active layer and the third routing layer. With this arrangement, the routing between the ASIC chip and the MEMS chip is located internally within the chip, shortening the signal transmission distance between the ASIC chip and the MEMS chip, thereby helping to increase the signal transmission speed between the MEMS chip and the ASIC chip. Furthermore, the electrical connection between the MEMS chip and the ASIC chip does not require the gold wires required for wire bonding, which also helps reduce the production cost of the MEMS microphone.

[0016] In one possible embodiment, the connection layer is a chip bonding film, which is bonded between the support frame and the chip body; the MEMS microphone also includes a first wire, a second wire, and a third wire, wherein 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. Under this arrangement, on the one hand, wire bonding is used to electrically connect the MEMS chip to the ASIC chip, and the ASIC chip to the circuit board, resulting in better connection reliability between the produced MEMS chip and the ASIC chip. On the other hand, the wire bonding process is less expensive than the wafer bonding process, which is also conducive to reducing the production cost of the MEMS microphone. At the same time, there is no need to set up an additional routing layer inside the ASIC chip, which helps to simplify the production process of the MEMS microphone and improve the production efficiency of the MEMS microphone.

[0017] In one possible implementation, the active layer and the chip body are sequentially stacked on the surface of the connection layer facing away from the support frame. For example, flip-chip bonding can be used to electrically connect the active layer of the ASIC chip to the MEMS chip via the solder layer. This eliminates the need for additional wiring within the ASIC chip, simplifying the MEMS microphone production process and improving production efficiency.

[0018] In one possible embodiment, the back plate is provided with a plurality of through holes, which penetrate the back plate along the thickness direction of the back plate and are spaced apart from each other and are all connected to the sound cavity of the MEMS so that sound signals from the external environment can enter the MEMS chip.

[0019] In one possible embodiment, the MEMS microphone further includes a housing, which is fixedly mounted to the circuit board and houses the MEMS chip and the ASIC chip. Exemplarily, the housing is made of a metal material. The housing can protect the MEMS chip and the ASIC chip and prevent other electromagnetic signals from interfering with the normal operation of the MEMS chip and the ASIC chip.

[0020] In a second aspect, the present application further provides an electronic device comprising a processor and the aforementioned MEMS microphone, wherein the processor is electrically connected to the MEMS microphone. The electronic device provided by the present application, by providing the aforementioned MEMS microphone, helps to achieve a lightweight and thin design of the electronic device.

[0021] In a third aspect, the present application also provides a method for preparing a MEMS microphone, comprising: providing a microphone intermediate and a circuit board, wherein the microphone intermediate comprises a silicon substrate and an ASIC chip, wherein the silicon substrate comprises a support frame intermediate and a back plate, wherein the back plate is fixedly connected to the upper surface of the support frame intermediate, wherein the ASIC chip is mounted on the side of the silicon substrate and is electrically connected to the back plate, wherein the circuit board is provided with a sound hole, wherein the sound hole passes through 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; and forming a diaphragm on the surface of the first sacrificial layer away from the silicon substrate and the ASIC chip. The diaphragm is electrically connected to the ASIC chip; a second sacrificial layer is formed on the lower surface of the silicon substrate and the lower surface of the ASIC chip; the second sacrificial layer, the silicon substrate, and the first sacrificial layer are etched 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; and the MEMS chip and the ASIC chip are mounted on the circuit board to obtain a MEMS microphone, wherein the MEMS chip covers the acoustic hole and is electrically connected to the circuit board, the sound cavity of the MEMS chip communicates with the acoustic hole, and the ASIC chip is electrically connected to the circuit board. The method for preparing a MEMS microphone provided in this embodiment fixes the ASIC chip to the side of the MEMS chip through a wafer bonding process, making the assembled structure of the MEMS chip and ASIC chip more compact and reducing the installation space of the MEMS chip and ASIC chip in the MEMS microphone, thereby reducing the overall volume of the MEMS microphone, promoting the miniaturization design of the MEMS microphone, and further contributing to the lightweight and thin design of electronic devices. On the other hand, the mounting area occupied by the MEMS chip and the ASIC chip on the circuit board is reduced. Compared with the area of ​​the circuit board used in existing MEMS microphones, the area of ​​the circuit board used in the MEMS microphone provided by this application is reduced by 50%, thereby saving the materials required to make the circuit board and the housing, which is conducive to saving the production cost of the MEMS microphone.

[0022] In one possible embodiment, the step of providing the microphone intermediate body and the circuit board includes: forming a first routing layer on the upper surface of the backplate and the upper surface of the ASIC chip, the first routing layer electrically connecting the backplate and the ASIC chip; and 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 covering the first routing layer. Providing the first routing layer enables electrical connection between the backplate and the ASIC chip.

[0023] In one possible embodiment, after forming a first sacrificial layer on the upper surface of the silicon substrate and the upper surface of the ASIC chip, and before forming a diaphragm on a surface of the first sacrificial layer facing away from the silicon substrate and the ASIC chip, the method for manufacturing a MEMS microphone further includes: forming a first electrical connection portion in the first sacrificial layer, the first electrical connection portion being spaced apart from the first routing layer and electrically connected to the ASIC chip; and 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 manufacturing a MEMS microphone further includes: forming a second electrical connection portion in the diaphragm and the first sacrificial layer, the second electrical connection portion being electrically connected to both the first electrical connection portion and the diaphragm, thereby forming a second routing layer, the second routing layer being electrically connected between the diaphragm and the ASIC chip. Providing the second routing layer enables electrical connection between the diaphragm and the ASIC chip.

[0024] In one possible embodiment, 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 manufacturing a 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, the third electrical connection portion being electrically connected to the ASIC chip; in 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 portion; and after forming the second sacrificial layer on the lower surface of the silicon substrate and the lower surface of the ASIC chip, and before 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 manufacturing a MEMS microphone further includes: forming a fourth electrical connection portion in the second sacrificial layer, the fourth electrical connection portion being electrically connected to the third electrical connection portion to form a third routing layer, the third routing layer being electrically connected to the ASIC chip. Providing the third routing layer enables electrical connection between the ASIC chip and the circuit board.

[0025] In one possible embodiment, the steps of providing a microphone intermediate and a circuit board include: installing 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 the 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 backpolar plate intermediate and the support frame intermediate, wherein the backpolar plate intermediate is fixedly connected to the upper surface of the support frame intermediate; etching the backpolar plate intermediate to form a plurality of through holes to obtain the backpolar plate, wherein the plurality of through holes are spaced apart and all pass through the backpolar plate along the thickness direction of the backpolar plate and are connected to the cavity.

[0026] In one possible embodiment, the step of mounting the MEMS chip on the circuit board to obtain the MEMS microphone includes: fixing a housing to the circuit board, with the housing covering 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 operation of the MEMS chip and the ASIC chip.

[0027] In a fourth aspect, the present application also provides a method for manufacturing a MEMS microphone, comprising: providing a MEMS chip, an ASIC chip, and a circuit board, the circuit board having an acoustic hole extending through the circuit board along its thickness; mounting the ASIC chip on a side of the MEMS chip, wherein the ASIC chip is electrically connected to the MEMS chip; and mounting the MEMS chip on the circuit board to obtain a MEMS microphone, wherein the MEMS chip covers the acoustic hole and is electrically connected to the circuit board, the sound cavity of the MEMS chip communicates with the acoustic hole, and the ASIC chip is electrically connected to the circuit board. The method for manufacturing a MEMS microphone provided in this embodiment makes the assembled structure of the MEMS chip and ASIC chip more compact and reduces the installation space of the MEMS chip and ASIC chip in the MEMS microphone, thereby reducing the overall volume of the MEMS microphone, promoting the miniaturization of the MEMS microphone, and further contributing to the lightweight and thin design of electronic devices. Furthermore, the mounting area occupied by the MEMS chip and ASIC chip on the circuit board is reduced, thereby saving material required for the circuit board and housing, and reducing the production cost of the MEMS microphone.

[0028] In one possible embodiment, the ASIC chip includes a chip body and an active layer, the active layer being stacked on the chip body. The step of mounting the ASIC chip on the side of the MEMS chip includes wafer bonding the surface of the chip body facing away from the active layer to the side of the MEMS chip to form a connection layer. In this preparation method, the wiring between the ASIC chip and the MEMS chip, as well as the wiring between the ASIC chip and the circuit board, are both located inside the chip. This shortens the signal transmission distance between the ASIC chip and the MEMS chip, and between the ASIC chip and the circuit board, thereby helping to improve the signal transmission speed between the MEMS chip, the ASIC chip, and the circuit board.

[0029] In one possible embodiment, the ASIC chip includes a chip body and an active layer, the active layer being stacked on the chip body. The step of mounting the ASIC chip on the side of the MEMS chip includes soldering the surface of the chip body facing away from the active layer to the side of the MEMS chip to form a first solder portion, a second solder portion, and a third solder portion, thereby obtaining a connecting layer. This preparation method utilizes a soldering process to secure the MEMS chip to the ASIC chip, resulting in a relatively low cost and reducing the production cost of the MEMS microphone 120.

[0030] In one possible embodiment, the step of attaching the ASIC chip to the side of the MEMS chip includes: providing an anisotropic conductive adhesive film; securing the anisotropic conductive adhesive film to the side of the MEMS chip; and attaching the ASIC chip to the surface of the anisotropic conductive adhesive film facing away from the MEMS chip. By attaching the anisotropic conductive adhesive film, an electrical connection between the MEMS chip and the ASIC chip is achieved, simplifying the process and improving the production efficiency of MEMS microphones.

[0031] In one possible embodiment, 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 arranged on the surface of the back plate away from the support frame, the diaphragm is arranged on the surface of the first support layer away from the back plate, the first routing layer and the second routing layer are both arranged on the side of the back plate away from the support frame, the second routing layer is spaced apart from the first routing layer, and the third routing layer is arranged 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 connected to the The chip body is stacked; the step of installing the ASIC chip on the side of the MEMS chip includes: providing a chip adhesive film, a first wire, a second wire, and a third wire; fixing the chip adhesive film on the outer peripheral surface of the support frame; installing the ASIC chip on the surface of the chip adhesive film facing away from the support frame, and the chip body and the active layer are stacked in sequence on the surface of the chip adhesive film facing away from the support frame; electrically connecting the first wire between the first routing layer and the active layer; electrically connecting the second wire between the second routing layer and the active layer; and electrically connecting the third wire between the third routing layer and the active layer. In this preparation method, wire bonding is used to electrically connect the MEMS chip to the ASIC chip, and the ASIC chip to the circuit board, which has low production costs. At the same time, there is no need to set up an additional routing layer inside the ASIC chip, which helps to simplify the production process of the MEMS microphone and improve the production efficiency of the MEMS microphone. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings required for use in the embodiments of the present application or the background technology will be described below.

[0033] FIG1 is a schematic structural diagram of an electronic device provided in an embodiment of the present application;

[0034] FIG2 is a schematic diagram of the structure of a MEMS microphone in the electronic device shown in FIG1 ;

[0035] FIG3 is a schematic structural diagram of the MEMS microphone shown in FIG2 in the first embodiment after being cut along line AA;

[0036] FIG4 is a schematic diagram of the structure of the ASIC chip in the MEMS microphone shown in FIG3 ;

[0037] FIG5 is a schematic structural diagram of the MEMS microphone shown in FIG2 in a second embodiment after being cut along line AA;

[0038] FIG6 is a schematic structural diagram of the MEMS microphone shown in FIG2 in a third embodiment after being cut along line AA;

[0039] FIG7 is a schematic structural diagram of the MEMS microphone shown in FIG2 in a fourth embodiment after being cut along line AA;

[0040] FIG8 is a schematic structural diagram of the MEMS microphone shown in FIG2 in a fifth embodiment after being cut along line AA;

[0041] FIG9 is a schematic structural diagram of the MEMS microphone shown in FIG2 in a sixth embodiment after being cut along line AA;

[0042] FIG10 is a schematic structural diagram of the MEMS microphone shown in FIG2 taken along line AA in a seventh embodiment;

[0043] FIG11 is a schematic flow chart of a method for preparing a first MEMS microphone according to an embodiment of the present application;

[0044] FIG12 is a schematic structural diagram of a silicon substrate of a microphone intermediate provided in step S1;

[0045] FIG13 is a schematic structural diagram of the microphone preform in step S11;

[0046] FIG14 is a schematic structural diagram of a plurality of etched grooves formed on a silicon substrate in step S12;

[0047] FIG15 is a schematic structural diagram of the cavity formed inside the silicon substrate in step S13;

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

[0049] FIG17 is a schematic structural diagram of the back plate obtained in step S15;

[0050] FIG18 is a schematic structural diagram after forming a first electrical connection portion in the first sacrificial layer in step S3;

[0051] FIG19 is a schematic structural diagram 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] FIG20 is a schematic structural diagram after obtaining the second routing layer in step S5;

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

[0054] FIG22 is a schematic structural diagram after obtaining the third routing layer in step S8;

[0055] FIG23 is a schematic structural diagram of the MEMS chip after obtaining it in step S9;

[0056] FIG24 is a schematic flow chart of a method for manufacturing a second MEMS microphone according to an embodiment of the present application;

[0057] FIG25 is a schematic structural diagram of a silicon substrate after a plurality of etching grooves are formed in step S101′;

[0058] FIG26 is a schematic structural diagram of the back plate intermediate and the support plate intermediate obtained in step S102′;

[0059] FIG27 is a schematic structural diagram of the first wiring layer formed on the upper surface of the back plate intermediate body in step S103′;

[0060] FIG28 is a schematic structural diagram of the back plate obtained in step S104′;

[0061] FIG29 is a schematic structural diagram after forming the first electrical connection portion in the first sacrificial layer in step S106′;

[0062] FIG30 is a schematic structural diagram of the first sacrificial layer after a diaphragm is formed on the surface facing away from the silicon substrate in step S107 ′;

[0063] FIG31 is a schematic structural diagram of the second wiring layer obtained in step S108′;

[0064] FIG32 is a schematic structural diagram of the structure after forming the third electrical connection portion on the lower surface of the silicon substrate in step S109′;

[0065] FIG33 is a schematic structural diagram of the third wiring layer obtained in step S111′;

[0066] FIG34 is a schematic structural diagram of the MEMS chip after obtaining it in step S112 ′. DETAILED DESCRIPTION

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

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

[0069] The present embodiment provides an electronic device 100. The electronic device 100 may be, but is not limited to, a mobile phone, a tablet computer, a television, headphones, a stereo, a personal computer (PC), a smart speaker, a smart screen, and a car display. The electronic device 100 may also be a gyroscope or other MEMS device with a large cavity.

[0070] In this embodiment, the electronic device 100 may include a housing 110, a middle frame 130, a processor 140, a display screen 150 and a MEMS microphone 120. The housing 110 and the display screen 150 are both mounted on the middle frame 130. The display screen 150 is arranged opposite to the housing 110. The display screen 150 is used to display images. The middle frame 130 is located between the display screen 150 and the housing 110. The processor 140 and the MEMS microphone 120 are both mounted inside the housing 110. The housing 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 achieve a sound collection function.

[0071] Please refer to FIG. 3 , which is a structural diagram of the MEMS microphone 120 shown in FIG. 2 cut along line AA in the first embodiment.

[0072] The MEMS microphone 120 includes a circuit board 10, a housing 20, a MEMS chip 30 and an ASIC chip 40. The MEMS chip 30, the ASIC chip 40 and the housing 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 passes through the circuit board 10 along the thickness direction of the circuit board 10 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 of the MEMS chip 30 and is electrically connected to both the MEMS chip 30 and the circuit board 10. The ASIC chip 40 and the MEMS chip 30 can be fixedly connected by a wafer bonding process. The MEMS chip 30 is used to sense and detect the sound signal flowing in from the sound hole 101, and convert the sound signal into an electrical signal and transmit it to the ASIC chip 40. The ASIC chip 40 receives the electrical signals output by the MEMS chip 30 and processes and amplifies them, thereby enabling the MEMS microphone 120 to provide sound reception for the electronic device 100. The housing 20 is fixedly mounted to the circuit board 10 and houses the MEMS chip 30 and the ASIC chip 40. Exemplarily, the housing 20 is made of metal. The housing 20 protects the MEMS chip 30 and the ASIC chip 40 and prevents other electromagnetic signals from interfering with the normal operation of the MEMS chip 30 and the ASIC chip 40.

[0073] Furthermore, 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 spaced apart from the circuit board 10. In this case, the MEMS microphone 120 may 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 electrically connecting the ASIC chip 40 to the circuit board 10. For example, the fixing member 50 may be a solder ball formed during the soldering process between the MEMS chip 30 and the circuit board 10.

[0074] Please continue to refer to Figure 3. The MEMS chip 30 includes a backplate 31, a support frame 32, a first support layer 34, a diaphragm 35, and a second support layer 38. The backplate 31 is fixedly connected to the side of the support frame 32 facing away from the circuit board 10. The first support layer 34 is provided on the surface of the backplate 31 facing away from the support frame 32. The diaphragm 35 is provided on the surface of the first support layer 34 facing away from the backplate 31. The second support layer 38 is provided on the surface of the support frame 32 facing away from the backplate 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 a sound cavity 30a. Specifically, the opening of the sound cavity 30a is arranged toward the circuit board 10. The sound cavity 30a is connected to the sound hole 101 so that the sound signal 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 all penetrate the back plate 31 along the thickness direction of the back plate 31 and are spaced apart from each other. Each through hole 311 is connected to the sound cavity 30a so that the sound signal can pass through the back plate 31.

[0076] In this embodiment, the first support layer 34 is provided on the surface of the back plate 31 facing away from the support frame 32 and the surface of the ASIC chip 40 facing away from the circuit board 10. Specifically, the circumferential surface of the first support layer 34 exceeds the circumferential surface of the back plate 31 and covers at least a portion 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 an avoidance hole 341, and the avoidance hole 341 passes through the first support layer 34 along the thickness direction of the first support layer 34. The avoidance hole 341 avoids the multiple through holes 311 of the back plate 31 to prevent the first support layer 34 from obstructing the transmission of the sound signal.

[0077] In this embodiment, the diaphragm 35 is provided on the surface of the first supporting layer 34 facing away from the back plate 31 and the surface of the first supporting layer 34 facing away from the ASIC chip 40. The orthographic projection of the diaphragm 35 on the back plate 31 covers at least a portion of the surface of the ASIC chip 40 facing away from the circuit board 10. Exemplarily, the material of the diaphragm 35 is polycrystalline silicon. 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 multiple 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 pickup mode of the MEMS microphone 120 is an upper pickup mode.

[0078] In this configuration, the ASIC chip 40 can support the diaphragm 35, significantly increasing the effective area of ​​the diaphragm 35. This speeds up the diaphragm 35's response to sound signals and reduces the acoustic conversion loss ratio of the diaphragm 35, thereby increasing the acoustic efficiency of the MEMS microphone 120 and enhancing the acoustic performance of the MEMS microphone 120. The acoustic efficiency of the MEMS microphone 120 provided in this application is 1.76 times that of existing MEMS microphones 120.

[0079] In other embodiments, the diaphragm 35 can also be fixedly connected to the support frame 32 and located on the side of the backplate 31 facing the circuit board 10, spaced apart from the backplate 31. In other words, the diaphragm 35 is located on the bottom side of the backplate 31. In this case, the MEMS microphone 120 adopts a bottom pickup mode. With this configuration, there is no need for an additional first support layer 34 between the diaphragm 35 and the backplate 31, thereby simplifying the structure of the MEMS chip 30 and streamlining the production process.

[0080] In this embodiment, the diaphragm 35 and the back plate 31 together form a capacitor structure. It is understood that sound signals from the external environment enter the sound cavity 30a of the MEMS chip 30 through the sound hole 101 of the circuit board 10, and pass through the back plate 31 to act on the diaphragm 35. When the diaphragm 35 is subjected to the sound pressure of the sound signal, it deforms, and the capacitance between the diaphragm 35 and the back plate 31 changes. The ASIC chip 40 can detect the change in capacitance between the diaphragm 35 and the back plate 31 and convert it into an electrical signal for output, thereby completing the sound-to-electricity conversion and enabling the MEMS microphone 120 to achieve the sound collection function.

[0081] In this embodiment, the second support layer 38 is disposed 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 circumference of the second support layer 38 extends beyond the outer circumference of the support frame 32 and covers at least a portion of the surface of the ASIC chip 40 facing the circuit board 10. The second support layer 38 allows the MEMS chip 30 to be securely connected to the circuit board 10.

[0082] The MEMS chip 30 further includes a first routing layer 33, a second routing layer 36, and a third routing layer 37. Exemplarily, the first routing layer 33, the second routing layer 36, and the third routing layer 37 are all made of copper. In other embodiments, the first routing layer 33, the second routing layer 36, and the third routing layer 37 may also be made of aluminum.

[0083] In this embodiment, the first routing layer 33 and the second routing layer 36 are both arranged on the side of the back plate 31 away from the support frame 32. The first routing layer 33 is arranged on the surface of the back plate 31 away from the support frame 32, and is covered on the first support layer 34, and is electrically connected between the back plate 31 and the ASIC chip 40. Exemplarily, the first routing layer 33 spans the surface of the back plate 31 away from the support frame 32 and the surface of the ASIC chip 40 close to the back plate 31. One end of the first routing layer 33 away from the back plate 31 is exposed relative to the peripheral surface of the first support layer 34. In some other embodiments, the first routing layer 33 may also be arranged on the surface of the back plate 31 away from the support frame 32, or the first routing layer 33 may also be arranged on the surface of the ASIC chip 40 close to the back plate 31. The embodiments of the present application do not limit this.

[0084] In this embodiment, the second routing layer 36 is spaced apart from the first routing layer 33. The second routing layer 36 is arranged inside the diaphragm 35 and the first supporting layer 34, and is electrically connected between the diaphragm 35 and the ASIC chip 40. Exemplarily, one end of the second routing layer 36 away from the diaphragm 35 is exposed relative to the first supporting layer 34 toward the surface of the back plate 31. Specifically, the second routing layer 36 includes a first electrical connection portion 361 and a second electrical connection portion 362 that are connected to each other. The first electrical connection portion 361 is arranged inside the first supporting layer 34 and is spaced apart from the first routing layer 33. The second electrical connection portion 362 is electrically connected to both the first electrical connection portion 361 and the diaphragm 35. A portion of the second electrical connection portion 362 is arranged inside the first supporting layer 34, and the other portion is arranged inside the diaphragm 35.

[0085] It can be understood that by setting the first routing layer 33 and the second routing 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 collection function of the MEMS microphone 120.

[0086] The third routing layer 37 is disposed 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 routing layer 37 closest to the ASIC chip 40 is exposed relative to the surface of the second support layer 38 facing the support frame 32. Specifically, the third routing layer 37 may include a third electrical connection portion 371 and a fourth electrical connection portion 372. The third electrical connection portion 371 spans 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 portion 372 is electrically connected to the third electrical connection portion 371.

[0087] In this embodiment, there may be multiple third routing layers 37. The multiple third routing layers 37 are spaced apart from each other. For example, there are two third routing layers 37. Both third routing layers 37 are electrically connected to the ASIC chip to facilitate the transmission of various electrical signals between the ASIC chip 40 and the circuit board 10. It should be noted that the shape and arrangement of each third routing layer 37 may be the same or different, depending on the specific electrical connection method between the MEMS chip and the ASIC chip.

[0088] Please refer to FIG. 4 , which is a schematic structural 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 stacked on the side of the MEMS chip 30. Specifically, the active layer 42 is arranged on the surface of the chip body 41 facing away from the MEMS chip 30. The ASIC chip 40 also includes a fourth routing layer 43, a fifth routing layer 44 and a sixth routing layer 45. The fourth routing layer 43, the fifth routing layer 44 and the sixth routing layer 45 are all arranged inside the chip body 41, and are spaced apart from each other, and are all electrically connected to the active layer 42. Exemplarily, the material of the fourth routing layer 43, the fifth routing layer 44 and the sixth routing layer 45 are all metallic copper. In some other embodiments, the material of the fourth routing layer 43, the fifth routing layer 44 and the sixth routing layer 45 can also be metallic aluminum, and the embodiments of the present application are not limited to this.

[0090] In this embodiment, the fourth routing layer 43 is electrically connected between the active layer 42 and the first routing layer 33, thereby electrically connecting the active layer 42 of the ASIC chip 40 to the back plate 31. Specifically, an end of the fourth routing layer 43, distal 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 first routing layer 33.

[0091] The fifth routing layer 44 is spaced apart from the fourth routing layer 43 and electrically connected between the active layer 42 and the second routing layer 36, thereby electrically connecting the active layer 42 of the ASIC chip 40 to the diaphragm 35. Specifically, the end of the fifth routing layer 44, distal 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 routing layer 36.

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

[0093] In addition, the MEMS microphone 120 further includes a connection layer 60, which is connected between the outer peripheral surface of the support frame 32 and the ASIC chip 40 to electrically connect the MEMS chip 30 to the ASIC chip 40. In this embodiment, the connection layer 60 is a wafer bonding layer 61, which electrically connects the first routing layer 33, the second routing layer 36, and the third routing 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 bonding the outer peripheral surface of the support frame 32 of the MEMS chip 30 to the surface of the chip body 41 of the ASIC chip facing away from the active layer 42 using a wafer bonding process.

[0094] In this embodiment, after the ASIC chip 40 is fixedly connected to the side of the MEMS chip 30, the MEMS chip 30 is fixed to the surface of the circuit board 10. At this point, the end of the third routing layer 37 facing away from the ASIC chip 40 is electrically connected to the circuit board 10, thereby electrically connecting the ASIC chip 40 and the circuit board 10, and thus enabling the MEMS chip 30 to be electrically connected to the circuit board 10 through the ASIC chip 40. In this arrangement, the routing between the ASIC chip 40 and the MEMS chip 30, as well as the routing between the ASIC chip 40 and the circuit board 10, are all located within the chips. This shortens 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, thereby helping to increase the signal transmission speed between the MEMS chip 30, the ASIC chip 40, and the circuit board 10. Furthermore, the electrical connections between the MEMS chip 30 and the ASIC chip 40, and between the ASIC chip 40 and the circuit board 10, do not require the gold wires required for wire bonding, thereby reducing the production cost of the MEMS microphone 120.

[0095] In this embodiment, by fixing the ASIC chip 40 to the side of the MEMS chip 30, the assembled structure of the MEMS chip 30 and the ASIC chip 40 can be made more compact and the installation space of the MEMS chip 30 and the ASIC chip 40 in the MEMS microphone 120 can be reduced. This can help reduce the overall volume of the MEMS microphone 120, promote the miniaturization of the MEMS microphone 120, and further contribute to the lightweight and thin design of the electronic device 100. Compared with existing MEMS microphones, the overall volume of the MEMS microphone 120 provided by this application is reduced by 30% to 40%. Furthermore, the mounting area occupied by the MEMS chip 30 and the ASIC chip 40 on the circuit board 10 is reduced, thereby saving the material required to manufacture the circuit board 10 and the housing 20, which helps reduce the production cost of the MEMS microphone 120. Compared with the area of ​​the circuit board 10 used in existing MEMS microphones 120, the area of ​​the circuit board 10 used in the MEMS microphone 120 provided by this application is reduced by 50%.

[0096] Please refer to FIG. 5 , which is a structural diagram of the MEMS microphone 120 shown in FIG. 2 cut along line AA in a second embodiment.

[0097] The MEMS microphone 120 described in this embodiment differs from the MEMS microphone 120 described in the first embodiment in that a first support layer 34 is provided on the surface of the backplate 31 facing away from the support frame 32. The circumference of the first support layer 34 is flush with the circumference of the backplate 31. A diaphragm 35 is provided on the surface of the first support layer 34 facing away from the backplate 31. The circumference of the diaphragm 35 is flush with the circumference of the first support layer 34. A second support layer 38 is provided on the surface of the support frame 32 facing the circuit board 10. The circumference of the second support layer 38 is flush with the circumference of the support frame 32.

[0098] In this embodiment, the first routing layer 33 is disposed on the surface of the backplate 31 facing away from the support frame 32, covers the first support layer 34, and is electrically connected between the backplate 31 and the ASIC chip 40, thereby achieving an electrical connection between the backplate 31 and the ASIC chip 40. Specifically, one end of the first routing layer 33 away from the backplate 31 is exposed relative to the peripheral surface of the first support layer 34.

[0099] The second routing layer 36 is disposed within the diaphragm 35 and the first support layer 34 and electrically connects the diaphragm 35 to the ASIC chip 40, thereby electrically connecting the diaphragm 35 to the ASIC chip 40. Specifically, one end of the second routing layer 36 away from the diaphragm 35 is exposed relative to the peripheral surface of the first support layer 34.

[0100] The third routing layer 37 is disposed on the side of the support frame 32 facing the circuit board 10 and covers the second supporting layer 38. It is electrically connected between the ASIC chip 40 and the circuit board 10, thereby electrically connecting the ASIC chip 40 to the circuit board 10 and, in turn, enabling the MEMS chip 30 to be electrically connected to the circuit board 10 through the ASIC chip 40. Specifically, the end of the third routing layer 37 proximate to the ASIC chip 40 is exposed relative to the circumference of the second supporting layer 38. Exemplarily, there are two third routing layers 37. The two third routing layers 37 are spaced apart. The ends of the two third routing layers 37 proximate to the ASIC chip 40 are both exposed relative to the circumference of the second supporting layer 38.

[0101] In this embodiment, one end of the fourth routing 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 routing layer 33, thereby achieving electrical connection between the active layer 42 of the ASIC chip 40 and the back plate 31.

[0102] The fifth routing layer 44 of the ASIC chip 40 is spaced apart from the fourth routing layer 43. One end of the fifth routing layer 44, distal 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 routing layer 36, thereby electrically connecting the active layer 42 of the ASIC chip 40 to the diaphragm 35.

[0103] The sixth routing layer 45 of the ASIC chip 40 is located on the side of the fourth routing layer 43 and the fifth routing layer 44 that faces the circuit board 10, and is spaced apart from the fourth routing layer 43 and the fifth routing layer 44. The end of the sixth routing layer 45 that is remote 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 third routing layer 37. Exemplarily, there are two sixth routing layers 45. Each sixth routing layer 45 is electrically connected between the active layer 42 and one of the third routing layers 37.

[0104] In this embodiment, by providing internal traces within the MEMS chip 30 and the ASIC chip 40, the signal transmission distances between the ASIC chip 40 and the MEMS chip 30, and between the ASIC chip 40 and the circuit board 10, are shortened, thereby improving the signal transmission speeds between the MEMS chip 30, the ASIC chip 40, and the circuit board 10. Furthermore, the electrical connections between the MEMS chip 30 and the ASIC chip 40, and between the ASIC chip 40 and the circuit board 10, do not require the gold wires required for wire bonding, thereby reducing the production cost of the MEMS microphone 120.

[0105] Please refer to FIG. 6 , which is a structural diagram of the MEMS microphone 120 in FIG. 2 cut along line AA in a third embodiment.

[0106] The MEMS microphone 120 described in this embodiment differs from the MEMS microphone 120 described in the second embodiment in that the connection layer 60 is a solder layer 62. That is, the connection layer 60 is formed 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 disposed 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. A solder resist is applied between the first solder portion 621 and the second solder portion 622 to prevent contact between the first solder portion 621 and the second solder portion 622, thereby preventing short circuits between the MEMS chip 30 and the ASIC chip 40.

[0107] Specifically, the first solder portion 621 is electrically connected between the first routing layer 33 and the fourth routing layer 43 to electrically connect the first routing layer 33 to the active layer 42. The second solder portion 622 is electrically connected between the second routing layer 36 and the fifth routing layer 44 to electrically connect the second routing layer 36 to the active layer 42. The third solder portion 623 is electrically connected between the third routing layer 37 and the sixth routing layer 45 to electrically connect the third routing layer 37 to the active layer 42. Exemplarily, there are two third solder portions 623. Each third solder portion 623 is electrically connected between one third routing layer 37 and the sixth routing layer 45. In addition, solder resist is applied between the two third solder portions 623 to prevent short circuits caused by contact between adjacent third solder portions 623.

[0108] Under this setting, 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 cost of fixing the MEMS chip 30 and the ASIC chip 40 by welding process is low, which is conducive to reducing the production cost of the MEMS microphone 120.

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

[0110] The MEMS microphone 120 of this embodiment differs from the MEMS microphone 120 of the third embodiment in that the first wiring layer 33 is disposed inside the back plate 31 , wherein one end of the first wiring layer 33 away from the back plate 31 is exposed relative to the peripheral surface of the back plate 31 .

[0111] With this arrangement, the spacing between the first routing layer 33 and the second routing layer 36 can be increased. When the first solder portion 621 is electrically connected between the first routing layer 33 and the fourth routing layer 43, and the second solder portion 622 is electrically connected between the second routing layer 36 and the fifth routing layer 44, the distance between the first solder portion 621 and the second solder portion 622 is also increased, thereby preventing the first solder portion 621 and the second solder portion 622 from contacting each other. This prevents short circuits between the MEMS chip 30 and the ASIC chip 40 without the need for additional solder resist coating between the first solder portion 621 and the second solder portion 622.

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

[0113] The MEMS microphone 120 of this embodiment differs from the MEMS microphone 120 of the third embodiment described above in that the active layer 42 and the chip body 41 are sequentially laminated on the surface of the connection layer 60 facing away from the support frame 32. Exemplarily, the connection layer 60 is a solder layer 62. In other embodiments, the connection layer 60 may also be a wafer bonding layer 61 or anisotropic conductive film (ACF) 63.

[0114] In this embodiment, the first solder portion 621, the second solder portion 622, and the third solder portion 623 of the solder layer 62 are all disposed between the side surface of the MEMS chip 30 and the surface of the active layer 42 facing away from the chip body 41, and are spaced apart from each other. A solder resist is applied between the first solder portion 621 and the second solder portion 622 to prevent contact between the first solder portion 621 and the second solder portion 622, thereby preventing a short circuit between the MEMS chip 30 and the ASIC chip 40.

[0115] Specifically, the first solder portion 621 is electrically connected between the first routing layer 33 and the active layer 42. The second solder portion 622 is electrically connected between the second routing layer 36 and the active layer 42. The third solder portion 623 is electrically connected between the third routing layer 37 and the active layer 42. Exemplarily, there are two third solder portions 623. Each third solder portion 623 is electrically connected between one third routing layer 37 and the active layer 42. Furthermore, solder resist is applied between the two third solder portions 623 to prevent short circuits caused by contact between adjacent third solder portions 623.

[0116] In this embodiment, flip-chip bonding is employed to electrically connect the active layer 42 of the ASIC chip 40 to the MEMS chip 30 via the solder layer 62. This eliminates the need for additional wiring within the ASIC chip 40, thereby simplifying the production process of the MEMS microphone 120 and improving the production efficiency of the MEMS microphone 120.

[0117] Please refer to FIG. 9 , which is a structural diagram of the MEMS microphone 120 shown in FIG. 2 cut along line AA in a sixth embodiment.

[0118] The MEMS microphone 120 described in this embodiment differs from the MEMS microphone 120 described in the third embodiment in that the connection layer 60 is an anisotropic conductive film (ACF) 63. The ACF 63 includes a first conductive portion 631 and a second conductive portion 632. The first conductive portion 631 is electrically connected between the first trace layer 33, the second trace layer 36, and the active layer 42. The second conductive portion 632 is located on the side of the first conductive portion 631 facing the circuit board 10 and is electrically connected between the third trace layer 37 and the active layer 42. Exemplarily, the second conductive portion 632 is fixedly connected to the first conductive portion 631. In other embodiments, the second conductive portion 632 may be spaced apart from the first conductive portion 631.

[0119] It is understood that the anisotropic conductive film 63 contains conductive particles that can transmit the electrical signal indicating the capacitance change between the back plate 31 and the diaphragm 35 to the ASIC chip 40, thereby electrically connecting the MEMS chip 30 to the ASIC chip 40. It should be noted that the conductive particles in the anisotropic conductive film 63 move only along the thickness direction of the anisotropic conductive film 63 to ensure that the anisotropic conductive film 63 is conductive only in the thickness direction. This ensures that the circuit formed between the first wiring layer 33 and the active layer 42, and the circuit formed between the second wiring layer 36 and the active layer 42, do not intersect, thereby preventing short circuits between the MEMS chip 30 and the ASIC chip 40.

[0120] Furthermore, the fixing member 50 of the MEMS microphone 120 is also made of anisotropic conductive adhesive film, enabling electrical connection between the MEMS chip 30 and the circuit board 10 via the ASIC chip 40. With this arrangement, the electrical connections between the MEMS chip 30 and the ASIC chip 40, and between the MEMS chip 30 and the circuit board 10, can be achieved simply by bonding the anisotropic conductive adhesive film 63 between the MEMS chip 30 and the ASIC chip 40, and between the MEMS chip 30 and the circuit board 10. This simplifies the operation and helps improve the production efficiency of the MEMS microphone 120.

[0121] Please refer to FIG. 10 , which is a structural diagram of the MEMS microphone 120 shown in FIG. 2 cut along line AA in a seventh embodiment.

[0122] The MEMS microphone 120 of this embodiment differs from the MEMS microphone 120 of the third embodiment in that the connection layer 60 is a die attach film (DAF) 64. The die attach film 64 is bonded between the support frame 32 of the MEMS chip 30 and the chip body 41 to securely connect the MEMS chip 30 to the ASIC chip 40.

[0123] In this embodiment, the MEMS chip 30 and the ASIC chip 40, as well as the ASIC chip 40 and the circuit board 10, are electrically connected via wire bonding. Specifically, the MEMS microphone 120 further includes a first conductive wire 70, a second conductive wire 80, and a third conductive wire 90. The first conductive wire 70 is electrically connected between the first routing layer 33 and the active layer 42 to electrically connect the backplate 31 to the ASIC chip 40. The second conductive wire 80 is electrically connected between the second routing layer 36 and the active layer 42 to electrically connect the diaphragm 35 to the ASIC chip 40. The third conductive wire 90 is electrically connected between the third routing layer 37 and the active layer 42 to electrically connect the ASIC chip 40 to the circuit board 10, thereby electrically connecting the MEMS chip 30 to the circuit board 10 via the ASIC chip 40. Exemplarily, there are two third conductive wires 90. Each third conductive wire 90 is electrically connected between the first and third routing layers 37 and the active layer 42.

[0124] This setup, on the one hand, uses wire bonding to electrically connect the MEMS chip 30 to the ASIC chip 40, and on the other hand, to the circuit board 10. This results in a more reliable connection between the MEMS chip 30 and the ASIC chip 40. Furthermore, wire bonding is more cost-effective than wafer bonding, which helps reduce the production cost of the MEMS microphone 120. Furthermore, no additional wiring layers are required within the ASIC chip 40, simplifying the production process for the MEMS microphone 120 and improving its production efficiency.

[0125] Please refer to Figures 11 to 23. The present application also provides a first method for manufacturing a MEMS microphone 120, which is used to manufacture the MEMS microphone 120 in the first embodiment.

[0126] Step S1: Provide a microphone intermediate body 121 and a circuit board. 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 backplate 31, which is fixedly connected to the upper surface of the support frame intermediate body 32a. The ASIC chip 40 is mounted on a side of the silicon substrate 121a and is electrically connected to the backplate 31. The circuit board is provided with an acoustic hole that extends through the thickness of the circuit board.

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

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

[0129] Step S12, etching the silicon substrate 121a to form a plurality of etched grooves 121c. The plurality of etched grooves 121c are spaced apart from one another. The openings of the plurality of etched grooves 121c are all located on the upper surface of the silicon substrate 121a, and the plurality of etched grooves 121c are all recessed from the upper surface of the silicon substrate 121a toward the lower surface of the silicon substrate 121a. The distance between the centers of the openings of two adjacent etched grooves 121c is between 0.1 μm and 1 μm. The width of the opening of each etched groove 121c is between 0.1 μm and 1 μm. The depth of each etched groove 121c is between 1 μm and 10 μm.

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

[0131] In step S13, the microphone preform can be annealed using a VENSEN process. The VENSEN process uses a hydrogen atmosphere at a temperature between 1000°C and 1200°C. During this process, silicon atoms diffuse and fill the etched grooves 121c, sealing the openings of the etched grooves 121c. This forms a cavity 121d within the silicon substrate 121a.

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

[0133] In the above step S15, photoresist can be first coated on the upper surface of the back plate intermediate 31a and the upper surface of the ASIC chip 40, and then the area where the first wiring layer 33 is to be produced is formed through exposure, development and photolithography processes, and then the first wiring layer 33 is formed in the area where the first wiring layer 33 is to be produced by electroplating. Finally, the photoresist is removed to form a patterned first wiring layer 33.

[0134] In step S15, the back plate intermediate body 31a is etched to form a plurality of through holes 311, thereby obtaining the back plate 31. The plurality of through holes 311 are arranged at intervals, penetrate the back plate 31 along the thickness direction of the back plate 31, and communicate with the cavity 121d.

[0135] In step S15 , a first wiring layer 33 is provided on the upper surface of the back plate 31 and the upper surface of the ASIC chip 40 , wherein the first wiring layer 33 is electrically connected between the back plate 31 and the ASIC chip 40 .

[0136] In 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 routing 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 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 using a thermal oxidation method.

[0137] In step S2, a portion of the first sacrificial layer 34a fills the cavity 121d and the plurality of through-holes 311, and another portion is disposed on the upper surface of the back plate 31 and the upper surface of the ASIC chip 40. The portion of the first sacrificial layer 34a disposed on the upper surface of the back plate 31 and the upper surface of the ASIC chip 40 has a thickness between 1 μm and 4 μm.

[0138] In step S3, a first electrical connection portion 361 is formed in the first sacrificial layer 34a. The first electrical connection portion 361 is spaced apart from the first routing layer 33 and is electrically connected to the ASIC chip 40. For example, the first electrical connection portion 361 can be formed in the first sacrificial layer 34a using a damascene process.

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

[0140] In step S5, a second electrical connection portion 362 is formed in the diaphragm 35 and the first sacrificial layer 34a. The second electrical connection portion 362 is electrically connected to the first electrical connection portion 361 and the diaphragm 35, thereby forming a second wiring layer 36. The second wiring layer 36 is electrically connected between the diaphragm 35 and the ASIC chip 40. For example, through-silicon-via (TSV) technology can be used to form the second electrical connection portion 362 in the diaphragm 35 and the first sacrificial layer 34a. The material of the second electrical connection portion 362 can be copper, tungsten, or polysilicon.

[0141] In step S6, a third electrical connection portion 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 portion 371 is electrically connected to the ASIC chip 40. For example, the third electrical connection portion 371 can be formed on the lower surface of the silicon substrate 121a and the lower surface of the ASIC chip 40 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, and then the area where the third electrical connection portion 371 is to be formed is formed through exposure, development and photolithography processes, and then the third electrical connection portion 371 is formed in the area where the third electrical connection portion 371 is to be formed by electroplating. Finally, the photoresist is removed to form a patterned third electrical connection portion 371.

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

[0144] In step S8, a fourth electrical connection portion 372 is formed in the second sacrificial layer 38a. The fourth electrical connection portion 372 is electrically connected to the third electrical connection portion 371 to obtain a third wiring layer 37. The third wiring layer 37 is electrically connected to the ASIC chip 40. For example, the fourth electrical connection portion 372 can be formed in the second sacrificial layer 38a using through-silicon via technology.

[0145] In step S9, the second sacrificial layer 38a, the silicon substrate 121a, and the first sacrificial layer 34a are etched from the bottom surface of the silicon substrate 121a toward the top surface of the silicon substrate 121a to form the second support layer 38, the support frame 32, and the first support layer 34, thereby obtaining the MEMS chip 30. In step S9, the silicon substrate 121a is etched and polished to form the sound cavity 30a of the MEMS chip 30.

[0146] In step S10, the MEMS chip 30 and the ASIC chip 40 are mounted on the circuit board to form the MEMS microphone 120. The MEMS chip 30 covers the acoustic port and is electrically connected to the circuit board. The acoustic cavity 30a of the MEMS chip 30 communicates with the acoustic port. The ASIC chip 40 is electrically connected to the circuit board. Step S10 also includes securing a housing to the circuit board, with the housing housing the MEMS chip 30 and the ASIC chip 40.

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

[0148] Step S1', provide a MEMS chip 30, an ASIC chip and a circuit board. The circuit board is provided with an acoustic hole, which penetrates 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 routing layer 33, a second routing layer 36 and a third routing layer 37. The back plate 31 is fixedly connected to the side of the support frame 32 facing away from the circuit board. The first support layer 34 is provided on the surface of the back plate 31 facing away from the support frame 32. The diaphragm 35 is provided on the surface of the first support layer 34 facing away from the back plate 31. The first routing layer 33 and the second routing layer 36 are both provided on the side of the back plate 31 facing away from the support frame 32. The second routing layer 36 is spaced apart from the first routing layer 33. The third routing layer 37 is provided 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 stacked with the chip body.

[0149] The above step S1 ′ further includes steps S101 ′ to S112 ′.

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

[0151] Step S102 ′: annealing the silicon substrate 121 a to form a cavity 121 d inside the silicon substrate 121 a to obtain a back plate intermediate body 31 a and a support frame intermediate body 32 a . The back plate intermediate body 31 a is fixedly connected to the upper surface of the support frame intermediate body 32 a .

[0152] Step S103 ′: forming a first wiring layer 33 on the upper surface of the back plate intermediate body 31 a .

[0153] In some other embodiments, in step S103 ′, a first wiring layer 33 may be formed in the back plate intermediate body 31 a , wherein one end of the first wiring layer 33 away from the back plate 31 is exposed relative to the peripheral surface of the first sacrificial layer 34 a .

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

[0155] In the above step S104 ′, a first wiring layer 33 is provided on the upper surface of the back plate 31 , wherein the first wiring layer 33 is electrically connected to the back plate 31 .

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

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

[0158] In step S106 ′, a first electrical connection portion 361 is formed in the first sacrificial layer 34 a , wherein the first electrical connection portion 361 is spaced apart from the first wiring layer 33 .

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

[0160] In step S108 ′, a second electrical connection portion 362 is formed in the diaphragm 35 and the first sacrificial layer 34 a , wherein the second electrical connection portion 362 , the first electrical connection portion 361 and the diaphragm 35 are electrically connected to obtain a second wiring layer 36 .

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

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

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

[0164] In step S112 ′, the second sacrificial layer 38 a , the silicon substrate 121 a and the first sacrificial layer 34 a are etched from the lower surface of the silicon substrate 121 a toward the upper surface of the silicon substrate 121 a to form the second support layer 38 , the support frame 32 and the first support layer 34 , thereby obtaining the MEMS chip 30 .

[0165] Step S2 ′: mounting the ASIC chip 40 on the side of the MEMS chip 30 . The ASIC chip 40 is electrically connected to the MEMS chip 30 .

[0166] The above step S2′ can be accomplished in a variety of different implementations. For example, in a first implementation, the surface of the chip body facing away from the active layer is wafer-bonded to the side of the MEMS chip 30 to form a connection layer. In a second implementation, the surface of the chip body facing away from the active layer is soldered to the side of the MEMS chip 30 to form a first solder portion, a second solder portion, and a third solder portion to obtain a connection layer.

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

[0168] Step S21 ′: providing an anisotropic conductive adhesive film.

[0169] In step S22 ′, the anisotropic conductive film is fixedly mounted on the side surface of the MEMS chip 30 .

[0170] Step S23 ′: mounting the ASIC chip on the surface of the anisotropic conductive film facing away from the MEMS chip 30 .

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

[0172] Step S21 ”: providing a die bonding film, a first wire, a second wire, and a third wire.

[0173] In step S22 , the die bonding film is fixedly mounted on the outer peripheral surface of the support frame 32 .

[0174] In step S23 , the ASIC chip is mounted on the surface of the die bonding film facing away from the support frame 32 . The chip body and the active layer are sequentially stacked on the surface of the die bonding film facing away from the support frame 32 .

[0175] In step S24 , the first conductive wire is electrically connected between the first wiring layer 33 and the active layer.

[0176] Step S25 ″: electrically connect the second wire between the second wiring layer 36 and the active layer.

[0177] Step S26 ″: electrically connect the third wire to the third wiring layer 37 and the active layer.

[0178] In step S3', the MEMS chip 30 is mounted on the circuit board to form the MEMS microphone 120. The MEMS chip 30 covers the acoustic port and is electrically connected to the circuit board. The acoustic cavity 30a of the MEMS chip 30 communicates with the acoustic port, and the ASIC chip is electrically connected to the circuit board. In step S3', the following further steps are performed: A housing is fixedly mounted on the circuit board, with the housing housing the MEMS chip 30 and the ASIC chip 40.

[0179] The above are only some of the embodiments and implementations of this application. The scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection 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, and the sound hole 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, characterized in that: The ASIC chip comprises 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, characterized in that: The MEMS chip comprises a back plate, a support frame, a first support layer, a diaphragm and a second support layer, wherein the back plate is fixedly connected to a side of the support frame away from the circuit board, the first support layer is arranged on a surface of the back plate away from the support frame, the diaphragm is arranged on a surface of the first support layer away from the back plate, and the second support layer is arranged on a 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, characterized in that: The first supporting layer is also arranged on a surface of the ASIC chip facing away from the circuit board, and the diaphragm is also arranged 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 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, and the connection layer is connected between the outer peripheral surface of the support frame and the ASIC chip.

7. The MEMS microphone according to claim 6, characterized in that: The connection 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.

8. The MEMS microphone according to claim 6, characterized in that: 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, characterized in that: The connecting layer is an anisotropic conductive adhesive film, which includes a first conductive part and a second conductive part, wherein the first conductive part is electrically connected between the first routing layer, the second routing layer and the active layer, and 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, characterized in that: 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, and the sixth routing layer is located on a side of the fourth routing layer and the fifth routing layer facing the circuit board, and 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, characterized in that: The connection 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, wherein the first wire is electrically connected between the first wiring layer and the active layer, the second wire is electrically connected between the second wiring layer and the active layer, and the third wire is electrically connected between the third wiring 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, characterized in that: The back plate is provided with a plurality of through holes, and the plurality of through holes penetrate the back plate along the thickness direction of the back plate, are arranged at intervals from each other, and are all connected to the sound cavity of the MEMS.

15. The MEMS microphone according to claim 1, characterized in that: The MEMS microphone further comprises 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 and a circuit board are provided, wherein the microphone intermediate comprises a silicon substrate and an ASIC chip. The board 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, and 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; 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 to 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, characterized in that: The steps of providing a microphone intermediate and a circuit board include: A first wiring layer is formed 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, characterized in that: 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 the surface of the first sacrificial layer 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 the step of forming a diaphragm on the surface of the first sacrificial layer away from the silicon substrate and the ASIC chip, and before 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 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 wiring layer, and the second wiring layer is electrically connected between the diaphragm and the ASIC chip.

20. The method for preparing a MEMS microphone according to claim 17, characterized in that: After the step of forming a diaphragm on the surface of the first sacrificial layer away from the silicon substrate and the ASIC chip, and before 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 method for preparing the MEMS microphone further includes: A third electrical connection portion is formed on the lower surface of the silicon substrate and the lower surface of the ASIC chip, wherein the third electrical connection The 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 wiring layer, and the third wiring layer is electrically connected to the ASIC chip.

21. The method for preparing a MEMS microphone according to claim 17, characterized in that: The steps of providing a microphone intermediate 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 arranged at intervals from each other, and the 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 polar plate intermediate is etched to form a plurality of through holes to obtain the back polar plate, wherein the plurality of through holes are arranged at intervals, all penetrate the back polar plate along the thickness direction of the back polar plate, and all communicate with the cavity.

22. The method for preparing a MEMS microphone according to claim 17, characterized in that: 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, characterized in that: The ASIC chip includes a chip body and an active layer, and 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, characterized in that: The ASIC chip includes a chip body and an active layer, and 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, characterized in that: The step of mounting the ASIC chip on the side of the MEMS chip includes: Provide anisotropic conductive film; The anisotropic conductive adhesive 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, characterized in that: The MEMS chip comprises 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 arranged on the surface of the back plate away from the support frame, the diaphragm is arranged on the surface of the first support layer away from the back plate, the first routing layer and the second routing layer are both arranged on the side of the back plate away from the support frame, the second routing layer is arranged at intervals from the first routing layer, the third routing layer is arranged on the side of the support frame facing the circuit board, and 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; The step of mounting the ASIC chip on the side of the MEMS chip includes: providing a die bonding film, a first wire, a second wire, and a third wire; The chip bonding film is fixedly mounted on the outer peripheral surface of the support frame; Mounting the ASIC chip on the surface of the chip bonding film away from the support frame, and stacking the chip body and the active layer in sequence on the surface of the chip bonding film 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.

Images