A micro-electromechanical system microphone and wafer-level packaging method thereof

Abstract

The embodiment of the present invention discloses a micro-electromechanical system microphone and a wafer-level packaging method thereof. The micro-electromechanical system microphone comprises a MEMS acoustic chip, a connection component and an ASIC chip arranged in a stacked manner; the MEMS acoustic chip comprises a first substrate, a first electrode and a second electrode are arranged on a side of the first substrate close to the connection component; the connection component comprises a second substrate, a first through-hole, a second through-hole, a first wiring and a second wiring, a first conductive structure is arranged in the first through-hole, a second conductive structure is arranged in the second through-hole, the first conductive structure is electrically connected to the first electrode and the first wiring respectively, and the second conductive structure is electrically connected to the second electrode and the second wiring respectively; the ASIC chip comprises a third substrate and a third electrode and a fourth electrode located on a surface of a side of the third substrate close to the connection component, the third electrode is electrically connected to the first wiring, and the fourth electrode is electrically connected to the second wiring. The micro-electromechanical system microphone has a small size, low cost and high preparation efficiency.

Description

Technical Field

[0001] The embodiments of the present invention relate to semiconductor technology, and more particularly to a micro-electromechanical system microphone and a wafer-level packaging method thereof. Background Art

[0002] Microphones are micro-electromechanical system microphones that convert sound signals into electrical signals. There are many types of microphones, among which microphones based on micro-electromechanical system (MEMS) technology are widely used in mobile phones, computers, cameras, camcorders, and smart home products because they can withstand high reflow temperatures, are easy to integrate with CMOS processes and other audio circuits, and have improved noise cancellation performance and good RF and EMI suppression.

[0003] The main structure of a MEMS microphone is as follows: a cavity composed of a circuit board and a shell serves as an external packaging structure, a MEMS acoustic chip and an application specific integrated circuit (ASIC) chip are installed inside the cavity, the MEMS acoustic chip and the ASIC chip are electrically connected to each other, and are electrically connected to the external working circuit through the pads on the outer surface of the circuit board; in addition, a sound hole is provided on the external packaging structure of the MEMS microphone, which runs through the inside and outside of the cavity and is used to receive external sound signals.

[0004] At present, the position relationship between the MEMS acoustic chip and the ASIC chip inside the cavity is usually arranged in parallel, resulting in the current packaging process being unable to meet the needs of product miniaturization. In addition, the electrical connection between the MEMS acoustic chip and the ASIC chip is currently mainly achieved through the gold wire bonding process, which results in low preparation efficiency and high cost of MEMS microphones. Summary of the invention

[0005] An embodiment of the present invention provides a micro-electromechanical system microphone and a wafer-level packaging method thereof. The micro-electromechanical system microphone (hereinafter referred to as MEMS microphone) has the advantages of small size, low cost, and high preparation efficiency.

[0006] In a first aspect, an embodiment of the present invention provides a MEMS microphone, comprising a MEMS acoustic chip, a connection component and an ASIC chip arranged in layers;

[0007] The MEMS acoustic chip comprises a first substrate, and a first electrode and a second electrode are arranged on a side of the first substrate close to the connection component;

[0008] The connecting component includes a second substrate, a first through-via and a second through-via disposed in the second substrate, and a first wiring and a second wiring located on a side of the second substrate away from the first substrate, a first conductive structure is disposed in the first through-via, a second conductive structure is disposed in the second through-via, the first conductive structure is electrically connected to the first electrode and the first wiring respectively, and the second conductive structure is electrically connected to the second electrode and the second wiring respectively;

[0009] The ASIC chip includes a third substrate and a third electrode and a fourth electrode located on a surface of the third substrate close to the connecting component. The third electrode is electrically connected to the first wiring, and the fourth electrode is electrically connected to the second wiring.

[0010] Optionally, the ASIC chip further includes at least one fifth electrode located on a surface of the third substrate close to the connection component;

[0011] The ASIC chip also includes at least one third through-hole located in the third substrate and a third wiring located on the inner wall of the third through-hole and the surface of the third substrate away from the connecting component. The third through-hole corresponds to the fifth electrode one by one, and the third wiring is electrically connected to the fifth electrode.

[0012] Optionally, the cross-sectional shape of the third through hole taken along the first surface is a trapezoid, and the first surface is perpendicular to the surface of the third substrate close to the connecting component; the third through hole is filled with a protective layer; and a passivation layer is provided between the third wiring and the third substrate.

[0013] Optionally, the MEMS acoustic chip further includes: a vibration membrane;

[0014] A first groove is arranged on a surface of a side of the first substrate away from the connection component, the first substrate comprises a first protrusion surrounding the first groove, a second protrusion, and a first connection portion connecting the first protrusion and the second protrusion, a first electrode is arranged on a side of the first protrusion close to the connection component, a second electrode is arranged on a side of the second protrusion close to the connection component, a vibration membrane is arranged between the first protrusion and the second protrusion, and is arranged parallel to the first connection portion, and the vibration membrane is spaced a first preset distance from the first connection portion;

[0015] The first electrode is electrically connected to the vibration membrane; the second electrode is electrically connected to the first connection portion.

[0016] Optionally, an acoustic cavity is provided in the second substrate, and a vertical projection of the acoustic cavity on the first substrate at least partially overlaps with the first groove;

[0017] At least one fourth through hole is disposed in the vibration membrane, and at least one fifth through hole is disposed in the first connection portion.

[0018] Optionally, the acoustic cavity runs through the second substrate;

[0019] The acoustic cavity comprises a first cavity and a second cavity which are interconnected, the first cavity is located on a side close to the MEMS acoustic chip, the second cavity is located on a side away from the MEMS acoustic chip, and an opening area of ​​the first cavity is larger than an opening area of ​​the second cavity;

[0020] The second cavity at least partially exposes the electrodes on the surface of the ASIC chip.

[0021] Optionally, the MEMS microphone further includes: a housing, the housing surrounding the ASIC chip, the connection component and the MEMS acoustic chip;

[0022] The shell includes a first shell division close to the MEMS acoustic chip side and a second shell division close to the ASIC chip side, the first shell division is provided with a sound inlet hole; a plurality of fifth electrode lead-out portions are provided in the second shell division, the fifth electrode lead-out portions include a first lead-out division close to the ASIC chip side, a second lead-out division penetrating the second shell division and a third lead-out division away from the ASIC chip side, the second lead-out division is electrically connected to the first lead-out division and the third lead-out division respectively, the first lead-out division is electrically connected to the third wiring, and the third lead-out division is electrically connected to the external circuit.

[0023] Optionally, a first insulating layer is disposed between the first conductive structure and the side wall of the first through-hole; and a second insulating layer is disposed between the second conductive structure and the side wall of the second through-hole.

[0024] In a second aspect, an embodiment of the present invention further provides a wafer-level packaging method for a MEMS microphone, comprising:

[0025] Forming a MEMS acoustic wafer; the MEMS acoustic wafer includes a plurality of MEMS acoustic chips arranged in an array, the MEMS acoustic chip includes a first substrate, and a first electrode and a second electrode are disposed on a side of the first substrate close to the connecting component;

[0026] A connected wafer is formed; the connected wafer includes a plurality of connected components arranged in an array, the connected components include a second substrate, a first through-hole and a second through-hole disposed in the second substrate, and a first wiring and a second wiring located on a side of the second substrate away from the first substrate, a first conductive structure is disposed in the first through-hole, a second conductive structure is disposed in the second through-hole, the first conductive structure is electrically connected to the first wiring, and the second conductive structure is electrically connected to the second wiring;

[0027] Bonding the MEMS acoustic wafer and the communication wafer so that the first conductive structure is electrically connected to the first electrode, and the second conductive structure is electrically connected to the second electrode;

[0028] Forming an ASIC wafer; the ASIC wafer includes a plurality of ASIC chips arranged in an array, and the ASIC chip includes a third substrate and a third electrode and a fourth electrode located on a surface of the third substrate close to a side of the connecting component;

[0029] Cut the ASIC wafer to obtain multiple ASIC chips;

[0030] Mounting the plurality of ASIC chips correspondingly to the side of the communication wafer away from the MEMS acoustic wafer, electrically connecting the third electrode to the first wiring, and electrically connecting the fourth electrode to the second wiring;

[0031] Dicing MEMS acoustic wafers and connectivity wafers.

[0032] Optionally, the ASIC chip further includes at least one fifth electrode located on a surface of the third substrate close to the connection component; the ASIC chip further includes at least one third through-hole located in the third substrate and a third wiring located on an inner wall of the third through-hole and a surface of the third substrate away from the connection component, the third through-holes correspond one-to-one to the fifth electrodes, and the third wiring is electrically connected to the fifth electrodes;

[0033] After dicing the MEMS acoustic wafer and the interconnect wafer, it also includes:

[0034] A shell is formed; the shell surrounds the ASIC chip, the connection component and the MEMS acoustic chip; the shell includes a first shell section close to the MEMS acoustic chip and a second shell section close to the ASIC chip, the first shell section is provided with a sound inlet hole; a plurality of fifth electrode lead-out sections are provided in the second shell section, the fifth electrode lead-out sections include a first lead-out section close to the ASIC chip, a second lead-out section penetrating the second shell section and a third lead-out section away from the ASIC chip, the second lead-out section is electrically connected to the first lead-out section and the third lead-out section respectively, the first lead-out section is electrically connected to the third wiring, and the third lead-out section is electrically connected to the external circuit.

[0035] The MEMS microphone provided in the embodiment of the present invention is additionally provided with a connecting component, and the electrical connection between the MEMS acoustic chip and the ASIC chip is realized by using the conductive structure arranged in the through-hole of the connecting component and the wiring arranged on the surface of the connecting component. The MEMS microphone provided in the embodiment of the present invention, the ASIC chip, the connecting component and the MEMS acoustic chip are stacked, and the MEMS acoustic chip and the ASIC chip are electrically connected through the connecting component, thereby avoiding the problems of volume, cost and manufacturing efficiency caused by the MEMS acoustic chip and the ASIC chip being arranged in parallel and electrically connected through gold wires in the prior art, and has the advantages of small volume, low cost and high manufacturing efficiency; in addition, the size of the existing ASIC chip is usually smaller than the size of the MEMS chip, and the present solution realizes the electrical connection between the conductive structure and the ASIC chip by wiring arranged on the side of the connecting component close to the ASIC chip, thereby avoiding the need to redesign the ASIC chip with the same size as the MEMS acoustic chip, and realizing electrical connection with the MEMS acoustic chip when using a small-sized ASIC chip, thereby avoiding the need to increase the cost, and thus having higher practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a structural schematic diagram of a MEMS microphone provided by an embodiment of the present invention;

[0037] Figure 2 yes Figure 1 A schematic diagram of the top view of the MEMS microphone shown;

[0038] Figure 3 is a structural schematic diagram of a MEMS microphone provided by another embodiment of the present invention;

[0039] Figure 4 It is a schematic flow chart of a wafer-level packaging method for a MEMS microphone provided by an embodiment of the present invention;

[0040] Figure 5-Figure 10 is with Figure 4 The packaging flow chart corresponding to the wafer-level packaging method shown. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0042] Figure 1 is a schematic diagram of the structure of a MEMS microphone provided by an embodiment of the present invention, see Figure 1The MEMS microphone 10 comprises a MEMS acoustic chip 100, a connection component 200 and an ASIC chip 300 which are stacked; the MEMS acoustic chip 100 comprises a first substrate 101, and a first electrode 102 and a second electrode 103 are arranged on a side of the first substrate 101 close to the connection component 200; the connection component 200 comprises a second substrate 201, a first through-hole 202 and a second through-hole 203 arranged in the second substrate 201, and a first wiring 204 and a second wiring 205 located on a side of the second substrate 201 away from the first substrate 101, and the first through-hole A first conductive structure 206 is arranged in the hole 202, and a second conductive structure 207 is arranged in the second through hole 203. The first conductive structure 206 is electrically connected to the first electrode 102 and the first wiring 204 respectively, and the second conductive structure 207 is electrically connected to the second electrode 103 and the second wiring 205 respectively; the ASIC chip 300 includes a third substrate 301 and a third electrode 302 and a fourth electrode 303 located on a surface of the third substrate 301 on one side close to the connecting component 200, the third electrode 302 is electrically connected to the first wiring 204, and the fourth electrode 303 is electrically connected to the second wiring 205.

[0043] Exemplarily, the MEMS microphone 10 can be a microphone, such as a MEMS microphone, which can convert sound signals into electrical signals. Among them, the MEMS acoustic chip 100 can collect sound signals in real time and convert the sound signals into primary electrical signals; the ASIC chip 300 is electrically connected to the MEMS acoustic chip 100, and is used to further process the primary electrical signals output by the MEMS acoustic chip 100 and output them to the external working circuit. For example, the primary electrical signals can be operationally amplified by the ASIC chip 300. The embodiment of the present invention does not limit the structure of the MEMS acoustic chip 100 and the ASIC chip 300, and those skilled in the art can select any known MEMS acoustic chip 100 and ASIC chip 300. Exemplarily, the materials of the first substrate 101 and the third substrate 301 can both be silicon.

[0044] The first electrode 102 and the second electrode 103 are output terminals of the MEMS acoustic chip 100, and the third electrode 302 and the fourth electrode 303 are input terminals of the ASIC chip 300. The first electrode 102 is electrically connected to the third electrode 302, and the second electrode 103 is electrically connected to the fourth electrode 303, so that the MEMS acoustic chip 100 and the ASIC chip 300 can be electrically connected. The specific pins of the first electrode 102, the second electrode 103, the third electrode 302 and the fourth electrode 303 in their corresponding chips are not limited here, and can be set according to the model of the selected chip.

[0045] It should be noted that, in this embodiment, only the first electrode 102 and the third electrode 302 as well as the second electrode 103 and the fourth electrode 303 are used as examples for explanation as corresponding electrically connected pins in the MEMS acoustic chip 100 and the ASIC chip 300. Depending on the chip model, the number of electrodes electrically connected to each other is not limited to two groups, and the embodiment of the present invention does not limit this.

[0046] In the prior art, the MEMS acoustic chip and the ASIC chip are arranged side by side, and the electrical connection between the electrodes corresponding to each other is achieved through gold wire bonding, so there are problems such as large size, high production cost and low manufacturing efficiency of the MEMS microphone. In the embodiment of the present invention, by providing a connecting component 200, the ASIC chip 300, the connecting component 200 and the MEMS acoustic chip 100 are stacked in sequence, and the connecting component 200 is used to achieve the electrical connection between the MEMS acoustic chip 100 and the ASIC chip 300, so that the size of the MEMS microphone 10 can be reduced.

[0047] Specifically, a first through hole 202 and a second through hole 203 are provided in the second substrate 201 of the connecting component 200, and a first conductive structure 206 and a second conductive structure 207 are provided in the first through hole 202 and the second through hole 203, respectively, and a first wiring 204 and a second wiring 205 are provided on a surface of a side of the second substrate 201 close to the ASIC chip 300, so that the first wiring 204 is electrically connected to the first conductive structure 206, and the second wiring 205 is electrically connected to the second conductive structure 207. The structure 206 is aligned and electrically connected to the first electrode 102, and the first wiring 204 is aligned and electrically connected to the third electrode 302, so that the first electrode 102 and the third electrode 302 are electrically connected; the second conductive structure 207 is aligned and electrically connected to the second electrode 103, and the second wiring 205 is aligned and electrically connected to the fourth electrode 303, so that the second electrode 103 and the fourth electrode 303 are electrically connected, thereby avoiding the efficiency and cost problems brought by the gold wire bonding process, making the cost of the MEMS microphone 10 lower and the preparation efficiency higher.

[0048] Exemplarily, the second substrate 201 may be a silicon substrate. Preferably, the material of the second substrate 201 is high-resistance silicon, so that the parasitic capacitance of the connecting component 200 can be reduced and the performance of the MEMS microphone can be improved. Exemplarily, the materials of the first conductive structure 206 and the second conductive structure 207 may be conductive polysilicon or metal conductive pillars, which is not limited in the embodiment of the present invention. Specifically, the through-holes and conductive structures mentioned above may be formed in the second substrate 201 using through silicon via (TSV) technology. Exemplarily, as Figure 1As shown, the size of the second substrate 201 can be set to be the same as that of the first substrate 101, and vertical first through-holes 202 and second through-holes 203 are set in the second substrate 201 at positions corresponding to the first electrodes 102 and the second electrodes 103, and a first conductive structure 206 is formed in the first through-hole 202, and a second conductive structure 207 is formed in the second through-hole 203, so that the MEMS acoustic chip 100 and the ASIC chip 300 are electrically connected in the vertical direction. In addition, see Figure 1 , an electrode 208 may be formed on the first conductive structure 206, and an electrode 209 may be formed on the second conductive structure 207, so that the first conductive structure 206 and the first electrode 102 are electrically connected by aligning and bonding the electrode 208 with the first electrode 102, and the second conductive structure 207 and the second electrode 103 are electrically connected by aligning and bonding the electrode 209 with the second electrode 103. Similarly, electrode structures that are aligned and bonded with the third electrode 302 and the fourth electrode 303, respectively, may also be formed on the first wiring 204 and the second wiring 205, which will not be described in detail here.

[0049] In addition, the size of the existing ASIC chip 300 is usually smaller than that of the MEMS acoustic chip 100. The present solution realizes electrical connection between the conductive structure and the ASIC chip 300 by means of the first wiring 204 and the second wiring 205 which are arranged on the side of the second substrate 201 close to the ASIC chip 300, thereby avoiding the need to redesign an ASIC chip with the same size as the MEMS acoustic chip. Electrical connection with the MEMS acoustic chip can be achieved while using a small-sized ASIC chip, thereby avoiding an increase in cost and thus being more practical.

[0050] The MEMS microphone provided in the embodiment of the present invention is additionally provided with a connecting component, and the electrical connection between the MEMS acoustic chip and the ASIC chip is realized by using the conductive structure arranged in the through-hole of the connecting component and the wiring arranged on the surface of the connecting component. The MEMS microphone provided in the embodiment of the present invention has a stacked arrangement of the ASIC chip, the connecting component and the MEMS acoustic chip, and the MEMS acoustic chip and the ASIC chip are electrically connected through the connecting component, thereby avoiding the problems of volume, cost and manufacturing efficiency caused by the MEMS acoustic chip and the ASIC chip being arranged in parallel and electrically connected through gold wires in the prior art, and has the advantages of small volume, low cost and high manufacturing efficiency; in addition, the MEMS microphone provided in the embodiment of the present invention can adopt the existing small-sized ASIC chip, and there is no need to redesign the chip consistent with the size of the MEMS, so it is more practical.

[0051] Based on the above embodiment, the structure of the MEMS microphone 10 is further described below.

[0052] See also Figure 1 Optionally, a first insulating layer 210 is disposed between the first conductive structure 206 and the side wall of the first through-hole 202 ; a second insulating layer 211 is disposed between the second conductive structure 207 and the side wall of the second through-hole 203 .

[0053] By isolating the first conductive structure 206 from the second substrate 201 using the first insulating layer 210 and isolating the second conductive structure 207 from the second substrate 201 using the second insulating layer 211, the leakage current of the connecting component 200 can be further reduced, and the performance of the MEMS microphone 10 can be improved. Exemplarily, the materials of the first insulating layer 210 and the second insulating layer 211 can be SiO 2 .

[0054] Continue to see Figure 1 Optionally, the ASIC chip 300 further includes at least one fifth electrode 304 located on the surface of the third substrate 301 on one side close to the connecting component 200; the ASIC chip 300 further includes at least one third through-hole located in the third substrate 301 and a third wiring 306 located on the inner wall of the third through-hole and on the surface of the third substrate 301 on one side away from the connecting component 200, the third through-holes correspond one to one with the fifth electrodes 304, and the third wiring 306 is electrically connected to the fifth electrode 304.

[0055] The fifth electrode 304 refers to a pin in the ASIC chip 300 that is electrically connected to an external circuit, that is, an output end of the ASIC chip 300, and can be set according to the chip model. Since the circuit area 305 of the ASIC chip 300 and the plurality of fifth electrodes 304 at its output end are located on the side of the third substrate 301 close to the connection component 200, in order to realize the electrical connection between the ASIC chip 300 and the external circuit, in the embodiment of the present invention, a third through hole corresponding to the fifth electrode 304 is provided in the third substrate 301, and a third wiring 306 is provided on the inner wall of the third through hole and on the surface of the third substrate 301 away from the connection component 200, so that the third wiring 306 is electrically connected to the fifth electrode 304, so that the fifth electrode 304 is extended to the lower surface of the third substrate 301 by using the third wiring 306, so as to facilitate the subsequent electrical connection between the ASIC chip 300 and the external circuit.

[0056] Continue to see Figure 1 Optionally, the cross-sectional shape of the third through-hole taken along the first surface is a trapezoid, and the first surface is perpendicular to the surface of the third substrate 301 close to the connecting component 200; the third through-hole is filled with a protective layer 307; and a passivation layer 308 is arranged between the third wiring 306 and the third substrate 301.

[0057] The third through hole is set to have a trapezoidal cross-sectional shape to facilitate the formation of the third wiring 306 on the sidewall of the third through hole. Since the third substrate 301 is mostly a silicon substrate, by setting a passivation layer 308 between the third wiring 306 and the third substrate 301, it can play an insulating role and improve product performance. For example, the material of the passivation layer 308 can be SiO 2 By filling the third through hole with a protective layer 307, such as a solder mask, the third wiring 306 can be prevented from contacting other metals, solder or conductive objects to cause a short circuit, and the third wiring 306 can be prevented from being corroded by water vapor in the environment, thereby improving product performance.

[0058] Continue to see Figure 1 Optionally, the MEMS acoustic chip 100 also includes: a vibration membrane 104; a first groove is arranged on the surface of the first substrate 101 on one side away from the connecting component 200, the first substrate 101 includes a first protrusion 1011 and a second protrusion 1012 surrounding the first groove, and a first connecting portion 1013 connecting the first protrusion 1011 and the second protrusion 1012, the first electrode 102 is arranged on the side of the first protrusion 1011 close to the connecting component 200, the second electrode 103 is arranged on the side of the second protrusion 1012 close to the connecting component 200, the vibration membrane 104 is arranged between the first protrusion 1011 and the second protrusion 1012, and is arranged parallel to the first connecting portion 1013, and the vibration membrane 104 is separated from the first connecting portion 1013 by a first preset distance; the first electrode 102 is electrically connected to the vibration membrane 104; the second electrode 103 is electrically connected to the first connecting portion 1013.

[0059] Figure 2 yes Figure 1 The schematic diagram of the top view of the MEMS microphone is shown in FIG. Figure 1 The MEMS acoustic chip 100 is shown along Figure 2 The cross-sectional structure taken at AA'. Figure 1 and Figure 2It can be seen that the first protrusion 1011, the second protrusion 1012 and the first connecting part 1013 are an integrated structure. After the first groove is formed on the first substrate 101, a vibration membrane 104 can be formed in the first groove, so that the vibration membrane 104 and the first connecting part 1013 are arranged in parallel. Exemplarily, the material of the vibration membrane 104 can be silicon. The first preset distance between the vibration membrane 104 and the first connecting part 1013 can be a distance in the micrometer range. A capacitor structure can be formed by the vibration membrane 104 and the first connecting part 1013, with the vibration membrane 104 as the upper plate of the capacitor and the first connecting part 1013 as the back plate of the capacitor. In this way, when a sound is emitted from the outside, a sound pressure signal will be formed. After the sound pressure signal acts on the highly sensitive vibration membrane 104, it will change the distance between the vibration membrane 104 and the first connecting part 1013, thereby causing a change in capacitance. Since the first electrode 102 is electrically connected to the vibration membrane 104, and the second electrode 103 is electrically connected to the first connecting part 1013 ( Figure 1 In this way, the capacitance change can be transmitted to the ASIC chip 300 through the first electrode 102 and the second electrode 103 to convert the capacitance change into a voltage signal change, and the voltage signal is amplified and output to the external circuit through the fifth electrode 304.

[0060] Continue to see Figure 1 Optionally, an acoustic cavity 212 is provided in the second substrate 201, and a vertical projection of the acoustic cavity 212 on the first substrate 101 at least partially overlaps with the first groove; at least one fourth through hole 1041 is provided in the vibration membrane 104, and at least one fifth through hole 105 is provided in the first connecting portion 1013.

[0061] By providing an acoustic cavity 212 in the second substrate 201, an acoustic resonant cavity can be provided for the MEMS microphone 10, so that the signal-to-noise ratio of the MEMS microphone 10 meets the specification requirements. The fourth through hole is provided in the vibration membrane 104 and the fifth through hole 105 is provided in the first connection portion 1013 so that the sound can be transmitted to the acoustic cavity 212 through the through hole. In addition, the product packaging process includes a baking or heating process, and the fourth through hole 1041 and the fifth through hole 105 can be provided to discharge hot air to avoid affecting the product quality.

[0062] Figure 3 FIG. 1 is a schematic diagram of the structure of a MEMS microphone provided by another embodiment of the present invention, and the structure of the MEMS microphone 10 is further refined on the basis of the above embodiment. Figure 3Optionally, the acoustic cavity 212 passes through the second substrate 201; the acoustic cavity 212 includes a first cavity and a second cavity that are interconnected, the first cavity is located on a side close to the MEMS acoustic chip 100, and the second cavity is located on a side away from the MEMS acoustic chip 100, and the opening area of ​​the first cavity is larger than the opening area of ​​the second cavity; the second cavity at least partially exposes the electrode on the surface of the ASIC chip 300.

[0063] Compared to Figure 1 As for the structure of the acoustic cavity 212 shown in FIG. 1 , such a configuration can expand the volume of the acoustic cavity 212 and further improve the signal-to-noise ratio of the MEMS microphone 10. Figure 1 In the structure shown in FIG. 1 , in order to prevent the second substrate 201 of the connection component 200 from directly contacting the electrodes or other conductive structures on the surface of the ASIC chip 300, it is often necessary to provide a support structure ( Figure 1 (not shown). In this embodiment, the second cavity exposes the electrodes on the surface of the ASIC chip 300, thereby avoiding the above situation and eliminating the need for a supporting structure.

[0064] Continue to see Figure 3 Optionally, the MEMS microphone 10 further includes: a shell, the shell surrounding the ASIC chip 300, the connecting component 200 and the MEMS acoustic chip 100; the shell includes a first shell division 401 close to the side of the MEMS acoustic chip 100 and a second shell division 402 close to the side of the ASIC chip 300, the first shell division 401 is provided with a sound inlet hole 4011; a plurality of fifth electrode lead-out portions 403 are provided in the second shell division 402, the fifth electrode lead-out portion 403 includes a first lead-out portion 4031 close to the side of the ASIC chip 300, a second lead-out portion 4032 penetrating the second shell division 402 and a third lead-out portion 4033 away from the side of the ASIC chip 300, the second lead-out portion 4032 is electrically connected to the first lead-out portion 4031 and the third lead-out portion 4033 respectively, the first lead-out portion 4031 is electrically connected to the third wiring 306, and the third lead-out portion 4033 is electrically connected to the external circuit.

[0065] The fifth electrode lead-out portion 403 is used to extend the fifth electrode 304 to an external circuit. When the fifth electrode 304 and the fifth electrode lead-out portion 403 are electrically connected in a one-to-one correspondence, the first housing portion 401 and the first substrate 101 (and / or the second housing portion 402) can be fixed with glue 500. In this way, the sound can be sensed by the vibration membrane 104 through the sound inlet hole 4011, causing a change in capacitance, and the capacitance change can be output to the external circuit by the fifth electrode lead-out portion 403 after being processed by the ASIC chip 300.

[0066] Based on the same inventive concept, an embodiment of the present invention further provides a wafer-level packaging method for a MEMS microphone, which is used to prepare the MEMS microphone provided by the above embodiment. Therefore, the wafer-level packaging method for a MEMS microphone provided by an embodiment of the present invention has the same technical effect as the technical solution in any of the above embodiments, and the structures identical or corresponding to the above MEMS microphone embodiments and the explanation of terms are not repeated here.

[0067] Figure 4 is a flow chart of a wafer-level packaging method for a MEMS microphone provided by an embodiment of the present invention, Figure 5-Figure 10 is with Figure 4 The packaging flow chart corresponding to the wafer-level packaging method shown below is combined with Figure 4-Figure 10 The preparation process of MEMS microphone is described as follows. Figure 4 , the packaging method comprises the following steps:

[0068] S21, forming a MEMS acoustic wafer; the MEMS acoustic wafer includes a plurality of MEMS acoustic chips arranged in an array, the MEMS acoustic chip includes a first substrate, and a first electrode and a second electrode are disposed on a side of the first substrate close to the connecting component.

[0069] Figure 5 The structure of the MEMS acoustic wafer is shown in Figure 5 In addition to the above structure, the MEMS acoustic chip 100 also includes a vibration membrane 104; a first groove is arranged on a surface of the first substrate 101 away from the connecting component 200, the first substrate 101 includes a first protrusion 1011 and a second protrusion 1012 surrounding the first groove, and a first connecting portion 1013 connecting the first protrusion 1011 and the second protrusion 1012; the first electrode 102 is arranged on a side of the first protrusion 1011 close to the connecting component 200, the second electrode 103 is arranged on a side of the second protrusion 1012 close to the connecting component 200, the vibration membrane 104 is arranged between the first protrusion 1011 and the second protrusion 1012, and is arranged parallel to the first connecting portion 1013, and the vibration membrane 104 is spaced a first preset distance from the first connecting portion 1013; the first electrode 102 is electrically connected to the vibration membrane 104; the second electrode 103 is electrically connected to the first connecting portion 1013. The embodiment of the present invention does not limit the method for preparing the MEMS acoustic wafer, and those skilled in the art can design it on their own.

[0070] S22. Form a connected wafer; the connected wafer includes a plurality of connected components arranged in an array, the connected components include a second substrate, a first through-via and a second through-via arranged in the second substrate, and a first wiring and a second wiring located on a side of the second substrate away from the first substrate, a first conductive structure is arranged in the first through-via, a second conductive structure is arranged in the second through-via, the first conductive structure is electrically connected to the first wiring, and the second conductive structure is electrically connected to the second wiring.

[0071] Figure 6 shows the structure of the interconnected wafers, see Figure 6 In addition to the above structure, a first insulating layer 210 is provided between the first conductive structure 206 and the side wall of the first through-hole 202, and a second insulating layer 211 is provided between the second conductive structure 207 and the side wall of the second through-hole 203, so as to reduce the parasitic capacitance and leakage current of the connecting component 200. The connecting wafer can be mainly prepared by TSV technology. Specifically, when preparing the connecting wafer, a dry deep silicon etching process is firstly used to etch the first through-hole 202 and the second through-hole 203 in the second substrate 201, and then a thermal oxygen or vapor deposition process is used to prepare the first insulating layer 210 and the second insulating layer 211 on the inner wall of the through-hole, and then the first conductive structure 206 and the second conductive structure 207 are deposited on the inner wall of the insulating layer. Finally, in order to achieve electrical connection between the MEMS acoustic chip 100 and the ASIC chip 300 in the vertical direction when using a small-sized ASIC chip 300 and improve the practicality of the MEMS microphone, a first wiring 204 and a second wiring 205 are formed on the surface of the second substrate 201 close to the ASIC chip 300.

[0072] In addition, optionally, an acoustic cavity 212 may be provided in the second substrate 201, so that the vertical projection of the acoustic cavity 212 on the first substrate 101 at least partially overlaps with the first groove, and at least one fourth through hole 1041 is provided in the vibration membrane 104, and at least one fifth through hole 105 is provided in the first connection portion 1013, so as to improve the signal-to-noise ratio of the MEMS microphone. Preferably, the acoustic cavity 212 penetrates the second substrate 201, and the acoustic cavity 212 includes a first cavity and a second cavity that are interconnected, the first cavity is located on a side close to the MEMS acoustic chip 100, and the second cavity is located on a side away from the MEMS acoustic chip 100, and the opening area of ​​the first cavity is larger than the opening area of ​​the second cavity, and the second cavity at least partially exposes the electrodes on the surface of the ASIC chip 300.

[0073] S23, bonding the MEMS acoustic wafer and the connection wafer, so that the first conductive structure is electrically connected to the first electrode, and so that the second conductive structure is electrically connected to the second electrode.

[0074] See also Figure 7The MEMS acoustic wafer and the connected wafer may be bonded by a wafer-level packaging process. For example, the bonding process may be a thermal bonding process or other bonding processes, which are not limited in the embodiment of the present invention.

[0075] S24, forming an ASIC wafer; the ASIC wafer includes a plurality of ASIC chips arranged in an array, and the ASIC chip includes a third substrate and a third electrode and a fourth electrode located on a surface of the third substrate close to a side of the connecting component.

[0076] Figure 8 shows the structure of the ASIC wafer, see Figure 8 In addition to the above structure, the ASIC chip 300 further includes at least one fifth electrode 304 located on the surface of the third substrate 301 close to the connection component 200; the ASIC chip 300 further includes at least one third through-hole located in the third substrate 301 and a third wiring 306 located on the inner wall of the third through-hole and the surface of the third substrate 301 away from the connection component 200. The third through-hole corresponds to the fifth electrode 304 one by one, and the third wiring 306 is electrically connected to the fifth electrode 304. Preferably, the cross-sectional shape of the third through-hole taken along the first surface is a trapezoid, and the first surface is perpendicular to the surface of the third substrate 301 close to the connection component 200; the third through-hole is filled with a protective layer 307; and a passivation layer is provided between the third wiring 306 and the third substrate 301.

[0077] Specifically, the ASIC wafer can be prepared by the following steps: First, temporary bonding is performed on the surface of one side of the ASIC wafer where the circuit area and the electrode are formed to protect the circuit area from the influence of subsequent processes. The embodiment of the present invention does not limit the formation of the circuit area and the electrode, and those skilled in the art can design it by themselves. Then, the third substrate 301 is thinned, and a third through-hole corresponding to the fifth electrode 304 is etched. Next, a passivation layer 308 is formed on the inner wall of the third through-hole and the surface of the third substrate 301 away from the connection component 200, and a metal conductive layer is deposited on the surface of the passivation layer 308, and the metal conductive layer is patterned (rewiring process) to form the third wiring 306. Finally, the protective layer 307 is filled, and a portion of the third wiring 306 for electrical connection to the fifth electrode lead-out portion 403 is exposed by a photolithography process.

[0078] S25, cutting the ASIC wafer to obtain multiple ASIC chips.

[0079] Specifically, along Figure 8 After the ASIC wafer is cut as shown by the dotted lines, a plurality of ASIC chips 300 can be obtained.

[0080] S26, mounting the plurality of ASIC chips correspondingly to the side of the connecting wafer away from the MEMS acoustic wafer, electrically connecting the third electrode to the first wiring, and electrically connecting the fourth electrode to the second wiring.

[0081] See also Fig. 9 , multiple ASIC chips 300 are correspondingly mounted on the side of the connected wafer away from the MEMS acoustic wafer. Specifically, multiple ASIC chips 300 can be correspondingly mounted on the connected wafer first, and then the third electrode 302 and the first wiring 204 and the fourth electrode 303 and the second wiring 205 are bonded to achieve electrical connection between the third electrode 302 and the first wiring 204, and the fourth electrode 303 and the second wiring 205. Exemplarily, the bonding process can be thermal bonding, such as a reflow soldering process, or other bonding processes, which are not limited in the embodiment of the present invention.

[0082] In summary, the wafer-level packaging method of the MEMS microphone provided in the embodiment of the present invention can realize electrical connection between the MEMS acoustic chip and the ASIC chip in the vertical direction by performing wafer-level packaging on the MEMS acoustic wafer and the connecting wafer, and aligning and bonding a single ASIC chip to the side of the connecting wafer away from the MEMS acoustic wafer. Compared with the packaging method of the prior art that uses a gold wire bonding process to realize side-by-side electrical connection between the two, this solution can reduce production costs, improve production efficiency, and effectively reduce the size of the MEMS microphone. In addition, this solution can realize electrical connection between the MEMS acoustic chip 100 and the ASIC chip 300 in the vertical direction when using a small-sized ASIC chip 300, which is beneficial to improving the practicality of the MEMS microphone.

[0083] S27, cutting the MEMS acoustic wafer and the connected wafer.

[0084] See also Fig. 9 ,along Fig. 9 After the MEMS acoustic wafer and the connected wafer are cut along the dotted line, the following can be obtained: Fig.10 The MEMS microphone is shown. After that, a housing can be formed. The specific structure of the housing is as follows: Figure 3 As shown, see Figure 3The shell surrounds the ASIC chip 300, the connecting component 200 and the MEMS acoustic chip 100; the shell includes a first shell division 401 close to the MEMS acoustic chip 100 and a second shell division 402 close to the ASIC chip 300, and the first shell division 401 is provided with a sound inlet hole 4011; a plurality of fifth electrode lead-out portions 403 are provided in the second shell division 402, and the fifth electrode lead-out portions 403 include a first lead-out portion 4031 close to the ASIC chip 300, a second lead-out portion 4032 penetrating the second shell division 402, and a third lead-out portion 4033 away from the ASIC chip 300, the second lead-out portion 4032 is electrically connected to the first lead-out portion 4031 and the third lead-out portion 4033 respectively, the first lead-out portion 4031 is electrically connected to the third wiring 306, and the third lead-out portion 4033 is electrically connected to the external circuit.

[0085] Exemplarily, when forming the shell, first Fig.10 The third wiring 306 in the MEMS microphone is mounted one-to-one with the fifth electrode lead-out portion 403 in the second housing portion 402, and then the first housing portion 401 with the sound inlet 4011 is attached to the second housing portion 402 to form a housing. Fig.10 The MEMS microphone 10 and its housing may be fixed and sealed by glue 500 .

[0086] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A micro-electromechanical system microphone, characterized in that: Including stacked MEMS acoustic chips, connectivity components and special application integrated circuit chips; The micro-electromechanical system acoustic chip comprises a first substrate, and a first electrode and a second electrode are arranged on a side of the first substrate close to the connecting component; The connecting component includes a second substrate, a first through-via and a second through-via disposed in the second substrate, and a first wiring and a second wiring located on a side of the second substrate away from the first substrate, a first conductive structure is disposed in the first through-via, a second conductive structure is disposed in the second through-via, the first conductive structure is electrically connected to the first electrode and the first wiring respectively, and the second conductive structure is electrically connected to the second electrode and the second wiring respectively; The application-specific integrated circuit chip includes a third substrate and a third electrode and a fourth electrode located on a surface of the third substrate close to the connecting component, the third electrode is electrically connected to the first wiring, and the fourth electrode is electrically connected to the second wiring; The application-specific integrated circuit chip further comprises at least one fifth electrode located on a surface of the third substrate close to the connecting component; The application-specific integrated circuit chip further includes at least one third through-hole located in the third substrate and a third wiring located on the inner wall of the third through-hole and on the surface of the third substrate away from the connecting component, the third through-hole corresponds to the fifth electrode one by one, and the third wiring is electrically connected to the fifth electrode; The cross-sectional shape of the third through-hole taken along the first surface is a trapezoid, and the first surface is perpendicular to the surface of the third substrate close to the connecting component; the third through-hole is filled with a protective layer; a passivation layer is provided between the third wiring and the third substrate; A first insulating layer is disposed between the first conductive structure and the side wall of the first through-hole; and a second insulating layer is disposed between the second conductive structure and the side wall of the second through-hole.

2. The MEMS microphone according to claim 1, characterized in that: The micro-electromechanical system acoustic chip further includes: a vibration membrane; A first groove is provided on a surface of the first substrate away from the connecting component, the first substrate comprises a first convex portion and a second convex portion surrounding the first groove, and a first connecting portion connecting the first convex portion and the second convex portion, the first electrode is provided on a side of the first convex portion close to the connecting component, the second electrode is provided on a side of the second convex portion close to the connecting component, the vibration membrane is provided between the first convex portion and the second convex portion, and is provided in parallel with the first connecting portion, and the vibration membrane is spaced a first preset distance from the first connecting portion; The first electrode is electrically connected to the vibration membrane; and the second electrode is electrically connected to the first connection portion.

3. The MEMS microphone according to claim 2, characterized in that: An acoustic cavity is provided in the second substrate, and a vertical projection of the acoustic cavity on the first substrate at least partially overlaps with the first groove; At least one fourth through hole is disposed in the vibration membrane, and at least one fifth through hole is disposed in the first connection portion.

4. The MEMS microphone according to claim 3, characterized in that: The acoustic cavity penetrates the second substrate; The acoustic cavity comprises a first cavity and a second cavity which are interconnected, the first cavity is located on a side close to the micro-electromechanical system acoustic chip, the second cavity is located on a side away from the micro-electromechanical system acoustic chip, and an opening area of ​​the first cavity is larger than an opening area of ​​the second cavity; The second cavity at least partially exposes the electrodes on the surface of the application specific integrated circuit chip.

5. The MEMS microphone according to claim 1, characterized in that: Also includes: A housing, the housing surrounding the ASIC chip, the connectivity component and the MEMS acoustic chip; The shell includes a first shell division close to the side of the micro-electromechanical system acoustic chip and a second shell division close to the side of the special application integrated circuit chip, and the first shell division is provided with a sound inlet hole; a plurality of fifth electrode lead-out portions are provided in the second shell division, and the fifth electrode lead-out portions include a first lead-out division close to the side of the special application integrated circuit chip, a second lead-out division penetrating the second shell division, and a third lead-out division away from the side of the special application integrated circuit chip, the second lead-out division is electrically connected to the first lead-out division and the third lead-out division respectively, the first lead-out division is electrically connected to the third wiring, and the third lead-out division is electrically connected to an external circuit.

6. A wafer-level packaging method for a micro-electromechanical system microphone, used to prepare the micro-electromechanical system microphone according to any one of claims 1 to 5, characterized in that: include: Forming a micro-electromechanical system acoustic wafer; the micro-electromechanical system acoustic wafer comprises a plurality of micro-electromechanical system acoustic chips arranged in an array, the micro-electromechanical system acoustic chip comprises a first substrate, and a first electrode and a second electrode are disposed on a side of the first substrate close to the connection component; A connected wafer is formed; the connected wafer includes a plurality of connected components arranged in an array, the connected components include a second substrate, a first through-via and a second through-via provided in the second substrate, and a first wiring and a second wiring located on a side of the second substrate away from the first substrate, a first conductive structure is provided in the first through-via, a second conductive structure is provided in the second through-via, the first conductive structure is electrically connected to the first wiring, and the second conductive structure is electrically connected to the second wiring; Bonding the MEMS acoustic wafer and the connection wafer so that the first conductive structure is electrically connected to the first electrode, and the second conductive structure is electrically connected to the second electrode; Forming a special application integrated circuit wafer; the special application integrated circuit wafer includes a plurality of special application integrated circuit chips arranged in an array, and the special application integrated circuit chip includes a third substrate and a third electrode and a fourth electrode located on a surface of the third substrate close to the connecting component; Cutting the application-specific integrated circuit wafer to obtain a plurality of application-specific integrated circuit chips; Mounting the plurality of application-specific integrated circuit chips correspondingly to the side of the communication wafer away from the MEMS acoustic wafer, so that the third electrode is electrically connected to the first wiring, and the fourth electrode is electrically connected to the second wiring; The MEMS acoustic wafer and the communication wafer are cut.

7. The method according to claim 6, characterized in that The application-specific integrated circuit chip further comprises at least one fifth electrode located on a surface of the third substrate close to the connection component; the application-specific integrated circuit chip further comprises at least one third through-hole located in the third substrate and a third wiring located on an inner wall of the third through-hole and a surface of the third substrate away from the connection component, the third through-hole corresponds to the fifth electrode one by one, and the third wiring is electrically connected to the fifth electrode; After cutting the micro-electromechanical system acoustic wafer and the connection wafer, the method further includes: A shell is formed; the shell surrounds the special application integrated circuit chip, the connecting component and the micro-electromechanical system acoustic chip; the shell includes a first shell division close to the side of the micro-electromechanical system acoustic chip and a second shell division close to the side of the special application integrated circuit chip, and the first shell division is provided with a sound inlet hole; a plurality of fifth electrode lead-out parts are provided in the second shell division, and the fifth electrode lead-out parts include a first lead-out division close to the side of the special application integrated circuit chip, a second lead-out division penetrating the second shell division and a third lead-out division away from the side of the special application integrated circuit chip, the second lead-out division is electrically connected to the first lead-out division and the third lead-out division respectively, the first lead-out division is electrically connected to the third wiring, and the third lead-out division is electrically connected to an external circuit.

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