MEMS microphone sensor

Abstract

The invention relates to the technical field of microphone sensors, in particular to an MEMS microphone sensor which comprises a packaging substrate, an MEMS chip and an ASIC chip, a sound hole is formed in the packaging substrate, the MEMS chip and the ASIC chip are stacked in the packaging substrate and electrically connected with the packaging substrate, and the MEMS chip is arranged corresponding to the sound hole. The application has the effect of considering the dual appeals of miniaturization and high-fidelity acoustic performance.

Description

Technical Field

[0001] This application relates to the technical field of microphone sensors, and in particular to a MEMS microphone sensor. Background Art

[0002] Currently, in the fields of consumer electronics, Internet of Things, and mobile communications, the miniaturization of devices and the integration of functions have become an irreversible technological trend. As a core component for voice interaction and environmental perception, the market demand for microelectromechanical system microphones (MEMS MIC) continues to climb with the explosive growth of intelligent terminal devices (such as TWS earphones, AR / VR headsets, miniature medical devices, etc.). The current mainstream packaging technology still mainly features a discrete architecture, that is, the microelectromechanical system (MEMS) acoustic sensor and the application-specific integrated circuit (ASIC) are arranged side by side in independent packages on the same plane of the PCB substrate. However, this approach exposes many thorny problems: on the one hand, the separate packages of the two components occupy a large area in the limited circuit board space, greatly hindering the progress of electronic products towards a more compact design. Products such as smartphones pursuing extremely narrow bezels and small and delicate wearable fitness trackers are difficult to achieve the ideal miniaturization goal due to the large packaging volume of MEMS MIC; on the other hand, the long signal transmission line makes the inherently weak electrical signal generated by the MEMS sensor extremely vulnerable to interference from the complex electromagnetic environment around the circuit board when reaching the ASIC processing link, resulting in problems such as sound signal distortion and noise mixing, seriously affecting the key performance indicators such as the sensitivity and signal-to-noise ratio of MEMS MIC.

[0003] Moreover, in related technologies, a MEMS microphone sensor usually consists of a MEMS chip, an ASIC chip, a sensor PCB board, and a sensor housing. Inside it, the MEMS chip and the ASIC chip generally adopt a planar layout method. Both are fixed on the PCB board and connected to the bottom pads through the vias of the PCB board to achieve surface mounting. Sound enters the MEMS microphone through the sound hole, causing the microphone diaphragm to vibrate, and then changing the capacitance to realize the conversion of sound signals into electrical signals. Subsequently, the electrical signal is amplified and processed by the ASIC and then output. The sound hole can be set on the housing or on the PCB board.

[0004] This planar layout design has the following problems and deficiencies: 1. Miniaturization: The planar layout limits the possibility of further reducing the size of the sensor. As the requirements for space utilization in electronic products become higher and higher, the difficulty of miniaturizing the sensor will have an adverse impact on the overall product design. For example, in application scenarios such as small wearable devices and miniature electronic instruments, such larger-sized sensors may not meet their space requirements.

[0005] 2. Signal interference: Since the MEMS chip and the ASIC chip are on the same plane and connected through a PCB board, they are more vulnerable to electromagnetic interference during signal transmission. Especially in a complex electromagnetic environment, it may cause signal distortion, affecting the sound quality and sensitivity of the microphone.

[0006] 3. Acoustic performance: Whether the sound hole is located on the housing or the PCB board, the planar layout may not be able to achieve the optimal design of the sound propagation path. During the acquisition of some high-frequency or low-frequency sounds, the acoustic performance may be poor due to the limitation of the sound propagation path. The traditional packaged MEMS microphone has a resonance at 20 kHz due to the large front cavity volume. Reducing the front cavity volume can increase the resonance frequency and avoid resonance in the audible range of 20 Hz - 20 kHz.

[0007] To address the above problems, the industry has tried planar heterogeneous integration solutions, such as integrating MEMS and ASIC in the form of system-in-package (SiP) on the same substrate. However, such technologies are limited by the physical constraints of two-dimensional layout, can only achieve limited space compression, and the electromagnetic compatibility (EMC) risk has not been fundamentally solved because the signal traces still need to be arranged horizontally.

[0008] Therefore, there is a problem that it is difficult to balance the dual requirements of miniaturization and high-fidelity acoustic performance, and there is an urgent need for a MEMS microphone sensor. Summary of the Invention

[0009] To balance the dual requirements of miniaturization and high-fidelity acoustic performance, the present application provides a MEMS microphone sensor.

[0010] A MEMS microphone sensor provided by the present application adopts the following technical solutions: A MEMS microphone sensor includes a packaging substrate, a MEMS chip, and an ASIC chip. A sound hole is provided on the packaging substrate. The MEMS chip and the ASIC chip are longitudinally stacked in the packaging substrate and are respectively electrically connected to the packaging substrate. The MEMS chip is arranged corresponding to the sound hole.

[0011] By adopting the above technical solution, the MEMS chip and the ASIC chip are stacked in the packaging matrix and electrically connected to the packaging matrix respectively. Thus, the stacking structure shortens the electrical signal transmission distance between the MEMS chip and the ASIC chip, reduces the attenuation and noise influence of the signal during transmission, and improves the efficiency and reliability of signal processing. Moreover, this design effectively reduces the planar size of the sensor and achieves higher space utilization. At the same time, the MEMS chip is set corresponding to the sound hole, and the sound signal can be more efficiently transmitted to the sensitive area of the MEMS chip, reducing the loss and interference in the sound propagation path, thereby improving the acquisition accuracy of the sound signal. Therefore, this technical solution not only realizes the miniaturization of the equipment, but also significantly enhances the acoustic performance and signal transmission quality of the microphone sensor, which is conducive to taking into account the dual demands of miniaturization and high-fidelity acoustic performance.

[0012] Optionally, the packaging base includes a substrate and a shell arranged on the substrate, a packaging cavity is formed between the shell and the substrate, the ASIC chip is located in the packaging cavity and electrically connected to the substrate, the MEMS chip is flip-chip mounted on the side of the ASIC chip facing away from the substrate, and the sound hole is opened on the shell and arranged close to the MEMS chip.

[0013] By adopting the above technical solution, the MEMS chip is flipped on the side of the ASIC chip facing away from the substrate, and the sound hole is opened in the housing near the MEMS chip. This design can significantly shorten the path of the sound signal from the sound hole to the MEMS chip diaphragm, thereby reducing energy loss and distortion during sound propagation. It can also optimize the angle and direction of sound entering the microphone, further improving the microphone's sensitivity and frequency response uniformity across the entire audio range, especially in the low and high frequency bands. These improvements not only improve the microphone's sound quality and voice recognition accuracy, but also make the microphone sensor more adaptable to the miniaturization and high performance requirements of modern electronic products.

[0014] At the same time, due to the vertical stacking between the MEMS chip and the ASIC chip, the signal transmission path is greatly shortened, effectively reducing the electromagnetic interference and parasitic capacitance effects of the signal during transmission, and improving the signal integrity and transmission efficiency.

[0015] Optionally, the ASIC chip is flip-chip mounted on the substrate, a conductive hole is opened on the ASIC chip, and the MEMS chip is electrically connected to the substrate through the conductive hole.

[0016] By adopting the above technical solution, the ASIC chip is flipped on the substrate, and conductive holes are opened in the ASIC chip, allowing the MEMS chip to be electrically connected to the substrate through the conductive holes. This design effectively shortens the signal transmission path and reduces the signal loss and electromagnetic interference problems caused by long-distance wiring in traditional planar layouts. At the same time, the conductive hole structure provides a stable vertical electrical connection channel, reducing the influence of parasitic capacitance and inductance, thereby improving the integrity and reliability of signal transmission. In addition, the application of flip-chip technology further optimizes the connection method between chips, enhances the compactness of the packaging structure, provides support for the miniaturization design of microphone sensors, and improves overall performance.

[0017] Optionally, the ASIC chip is flip-chip mounted on the substrate, and conductive holes are respectively opened on the ASIC chip and the MEMS chip, and the MEMS chip is electrically connected to the substrate through the conductive holes.

[0018] By adopting the above technical solution, both the ASIC chip and the MEMS chip are provided with conductive vias and connected to the substrate via a flip-chip method, thereby achieving vertical electrical connection between the chips. This design significantly shortens the signal transmission path, effectively reduces signal loss and interference during transmission, and improves signal integrity. At the same time, the conductive via structure reduces the parasitic capacitance and inductance problems caused by traditional planar wiring, further optimizes the transmission performance of high-frequency signals, and improves the microphone's capture accuracy and transmission efficiency of sound signals. In addition, this solution makes full use of three-dimensional space, reduces the size of the sensor in the planar direction, and provides more possibilities for the miniaturization design of electronic devices.

[0019] Optionally, the conductive holes on the ASIC chip are aligned with the conductive holes on the MEMS chip.

[0020] By adopting this technical solution, the aligned conductive vias significantly improve signal transmission efficiency and reduce contact resistance, thereby effectively improving signal integrity and minimizing signal loss and noise interference. This design optimizes the electromagnetic compatibility (EMC) performance of MEMS microphones, ensuring a high signal-to-noise ratio (SNR) even in high-density integration environments, thereby improving the accuracy of features such as voice wake-up and noise reduction algorithms.

[0021] Optionally, the packaging base includes a substrate and a shell arranged on the substrate, a packaging cavity is formed between the shell and the substrate, the MEMS chip is located in the packaging cavity and is flip-chip mounted on the substrate, a conductive hole is opened through the MEMS chip, the ASIC chip is flip-chip mounted on the side of the MEMS chip away from the substrate and is electrically connected to the substrate through the conductive hole, and the acoustic hole is opened on the substrate and arranged corresponding to the MEMS chip.

[0022] By adopting the above technical solution, the MEMS chip is flip-chip mounted on the substrate, and the ASIC chip is electrically connected to the substrate through the conductive vias formed on the MEMS chip. This vertical stacking method significantly reduces the wiring space required for the traditional planar layout, thereby greatly reducing the overall size of the microphone sensor. At the same time, the sound holes are formed on the substrate and are arranged corresponding to the MEMS chip, optimizing the sound propagation path, enabling the sound wave to act more directly on the diaphragm of the MEMS chip, and improving the acquisition efficiency and sensitivity of the sound signal. In addition, since the signal transmission path is greatly shortened, the parasitic capacitance and inductance effects are reduced, thereby reducing signal interference and distortion, ensuring the high-quality transmission and processing of the sound signal, and further enhancing the sound quality performance and speech recognition ability of the microphone.

[0023] Optionally, a plurality of limiting protrusions are arranged in the housing, the plurality of limiting protrusions are arranged at intervals from each other, and the plurality of limiting protrusions respectively abut against the peripheries of the MEMS chip and the ASIC chip.

[0024] By adopting the above technical solution, the arrangement of the limiting protrusions can accurately position the MEMS chip and the ASIC chip, prevent the chips from shifting or tilting in the encapsulation cavity, thereby improving the stability of the encapsulation structure. At the same time, the plurality of limiting protrusions are arranged at intervals from each other, which can effectively disperse the stress, avoid chip damage caused by stress concentration, and further enhance the encapsulation reliability. In addition, the limiting protrusions respectively abut against the peripheries of the MEMS chip and the ASIC chip, ensuring the position accuracy of the chips in the longitudinal stacking state, contributing to optimizing the signal transmission path, reducing signal loss, and enhancing the acoustic performance.

[0025] Optionally, the MEMS chip includes a substrate, a through-hole backplane, an isolation layer, a diaphragm, and an electrode sequentially arranged on the substrate. A sound cavity is formed between the through-hole backplane and the substrate, the sound cavity is arranged corresponding to the sound hole, and the electrode is used for electrically connecting to the encapsulation matrix.

[0026] By adopting the above technical solution, the sound cavity design between the through-hole backplane and the substrate optimizes the sound propagation path, reduces the energy loss of the sound wave during propagation, enables the sound signal to directly act on the diaphragm, thereby enhancing the acoustic performance of the microphone. In addition, the electrical connection between the electrode and the encapsulation matrix ensures the stable transmission of the electrical signal, further enhancing the sound signal capture ability of the microphone and achieving higher-quality sound restoration.

[0027] Optionally, the diaphragm is arranged close to or away from the sound hole.

[0028] By adopting the above technical solution, the diaphragm is arranged close to the sound hole, which can effectively shorten the distance for sound waves to travel from the sound hole to the diaphragm, reduce the energy loss and distortion of sound waves during propagation, and thus help ensure that sound signals are captured and converted in a more efficient and accurate manner, thereby improving the overall performance of the microphone. And when the diaphragm is arranged far from the sound hole, it can effectively reduce the direct impact of the external environment on the diaphragm and avoid mechanical damage and signal distortion caused by foreign objects or air flow in the sound hole directly hitting the diaphragm. At the same time, this layout optimizes the sound propagation path, enabling sound waves to be buffered and diffused appropriately after entering the sound cavity and then acting on the diaphragm, which helps improve the sensitivity and frequency response uniformity of the microphone in the low-frequency band, thereby enhancing the overall acoustic performance and the stability of sound signals.

[0029] Optionally, the diaphragm includes an inner layer film away from the sound hole and an outer layer film close to the sound hole. The inner layer film and the outer layer film are arranged in parallel at intervals. The inner layer film and the outer layer film are arranged between the isolation layer and the electrode, and the elastic modulus of the inner layer film is less than that of the outer layer film.

[0030] By adopting the above technical solution, the diaphragm is composed of an inner layer film and an outer layer film, which are arranged in parallel at intervals and have different elastic moduli. The inner layer film has a smaller elastic modulus and can generate a larger deformation under the action of sound waves, thereby improving the sensitivity to low-frequency sound signals; the outer layer film has a larger elastic modulus and can enhance the structural stability and reduce the excessive vibration caused by high-frequency sound signals, thereby improving the high-frequency response characteristics. The synergistic effect of the inner and outer layer films effectively improves the acoustic performance of the microphone and realizes high-fidelity audio acquisition with a wider frequency band.

[0031] In summary, the present application includes at least one of the following beneficial technical effects: 1. Through the vertical stacking and packaging method, the planar occupied area of the MEMS microphone sensor is effectively reduced, making it more suitable for the design requirements of miniaturized electronic devices, providing higher flexibility and integration for product design, and enhancing the acoustic performance and signal transmission quality of the microphone sensor, thus facilitating the dual demands of miniaturization and high-fidelity acoustic performance; 2. Conductive holes are opened on the ASIC chip, enabling the MEMS chip to be electrically connected to the substrate through these conductive holes, thereby effectively shortening the signal transmission path, reducing the signal loss and electromagnetic interference problems caused by long-distance wiring in the traditional planar layout, reducing the influence of parasitic capacitance and inductance, and further improving the integrity and reliability of signal transmission; 3. The conductive vias are formed by deep silicon etching, wet etching or laser drilling processes, which can precisely control the size and shape of the conductive vias, ensuring the position accuracy and consistency of the conductive vias in the MEMS chip and the ASIC chip, enhancing the anti-interference ability of the microphone sensor in a complex electromagnetic environment, ensuring the accurate capture and processing of sound signals, and thus improving the sound quality and the accuracy of speech recognition. Brief Description of the Drawings

[0032] Figure 1 is a schematic diagram of the overall structure of a MEMS microphone sensor in Embodiment 1 of the present application.

[0033] Figure 2 is a schematic diagram of the overall structure of a MEMS microphone sensor in Embodiment 2 of the present application.

[0034] Figure 3 is a schematic diagram of the overall structure of a MEMS microphone sensor in Embodiment 3 of the present application.

[0035] Figure 4 is a schematic diagram of the overall structure of a MEMS microphone sensor in Embodiment 4 of the present application.

[0036] Figure 5 is a schematic diagram of the overall structure of a MEMS microphone sensor in Embodiment 5 of the present application.

[0037] Figure 6 is a schematic diagram of the overall structure of a MEMS microphone sensor in Embodiment 6 of the present application.

[0038] Figure 7 is a schematic diagram of the overall structure of a MEMS microphone sensor in Embodiment 7 of the present application.

[0039] Description of the Reference Numerals: 1. Encapsulation matrix; 11. Substrate; 12. Housing; 121. Limit protrusion; 13. Encapsulation cavity; 14. Sound hole; 2. MEMS chip; 21. Substrate; 22. Through-hole backplane; 23. Isolation layer; 24. Diaphragm; 241. Inner layer film; 242. Outer layer film; 25. Electrode; 26. Sound cavity; 3. ASIC chip; 4. Conductive via; 41. Conductive dielectric layer. Detailed Description of the Embodiments

[0040] The following is a further detailed description of the present application in conjunction with the attached Figure 1-7 drawings.

[0041] Embodiments of the present application disclose a MEMS microphone sensor.

[0042] It should be noted that in the description of the present invention, it is to be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0043] Embodiment 1 Refer to Figure 1 , a MEMS microphone sensor includes a packaging substrate 1, a MEMS chip 2 and an ASIC chip 3. Among them, the MEMS chip 2 and the ASIC chip 3 are stacked in the packaging substrate 1 and are electrically connected to the packaging substrate 1 respectively, achieving the effects of significantly reducing the sensor size and optimizing the signal transmission path.

[0044] Specifically, the packaging substrate 1 includes a substrate 11 and a housing 12. Among them, the substrate 11 can be a PCB board or a board-like structure made of other materials with electrical connection functions, such as an FR-4 epoxy resin fiberglass board or a ceramic substrate 11. In this embodiment, the substrate 11 is a PCB board, and pads are provided on the PCB board to facilitate electrical connection with the MEMS chip 2 and the ASIC chip 3.

[0045] In this embodiment, the MEMS chip 2 and the ASIC chip 3 are electrically connected to the substrate 11 by wire bonding.

[0046] The housing 12 is fixed on the substrate 11, and a packaging cavity 13 is formed between the housing 12 and the substrate 11. In this embodiment, the housing 12 is fixed on the substrate 11 by a curing adhesive, and the housing 12 is usually made of materials such as metal or plastic, and is used to protect the chip components inside the sensor, and its shape can be rectangular, circular or other shapes adapted to the packaging requirements.

[0047] The ASIC chip 3 is located in the packaging cavity 13 and is electrically connected to the substrate 11. The MEMS chip 2 is flip-chip mounted on the side of the ASIC chip 3 facing away from the substrate 11, and a sound hole 14 is provided on the housing 12, and the MEMS chip 2 is arranged close to the sound hole 14.

[0048] The MEMS chip 2 includes a substrate 21 and a through-hole backplane 22, an isolation layer 23, a diaphragm 24 and an electrode 25 sequentially arranged on the substrate 21. Among them, the substrate 21 is usually made of a wafer of silicon (Si), glass, silicon-on-insulator (SOI) or other materials, and has good mechanical strength and thermal conductivity.

[0049] The through-hole backplane 22 can be a porous structure of materials such as Si, silicon dioxide (SiO2), silicon nitride (Si3N4), resin, etc., or a through-hole structure of multiple layers of the above materials. A sound cavity 26 is formed between the through-hole backplane 22 and the substrate 21, and the sound cavity 26 is arranged corresponding to the sound hole 14 for receiving sound signals.

[0050] By combining the optimized design of the sound hole 14 with the 3D packaging structure, the way sound enters the microphone and the acoustic characteristics are improved. The special structure of the sound hole 14 and the precise position layout can improve the sensitivity and frequency response uniformity of the microphone in the entire audio range (especially in the low-frequency and high-frequency bands), enabling the microphone to more realistically restore sound details and provide a better audio experience.

[0051] Refer to Figure 1 , the isolation layer 23 is usually made of SiO2 or other insulating materials with a thickness range of 0.1 μm to 10 μm to prevent short circuits between the electrodes 25. The diaphragm 24 is usually made of materials such as Si, polysilicon, Si3N4, aluminum (Al), gold (Au), etc., with a thickness range of 0.5 μm to 5 μm and can respond to sound vibrations.

[0052] The electrode 25 is usually made of a single layer of Al, Au, platinum (Pt), titanium (Ti), chromium (Cr), copper (Cu), nickel (Ni) or a multi-layer structure of different materials with a thickness range of 0.1 μm to 2 μm for converting sound signals into electrical signals.

[0053] The implementation principle of a MEMS microphone sensor in an embodiment of this application is as follows: The MEMS chip 2 is mounted on the ASIC chip 3 by using the flip-chip technology to achieve the vertical stacking packaging of the MEMS chip 2 and the ASIC chip 3, and a new 3D packaging architecture is constructed. This structure optimizes the spatial layout between the chips, greatly shortens the signal transmission path, reduces the loss and interference during signal transmission, improves signal integrity and transmission speed, ensures the accurate capture and processing of sound signals by the microphone, and further improves the sound quality and speech recognition accuracy.

[0054] Compared with the traditional planar layout, in the embodiment of this application, 3D packaging is achieved by vertically stacking chips, effectively reducing the size of the microphone sensor in the planar direction, enabling the sensor to better adapt to small electronic devices with demanding space requirements, such as smart phones, wearable devices, etc., providing more possibilities for the miniaturization design of products, and improving the integration and portability of electronic products.

[0055] In smartphones, smaller microphone sensors help achieve narrower bezel designs, freeing up more space for other components (such as larger batteries, higher-performance processors, etc.), improving the integration and portability of electronic products, while also providing more flexibility in product appearance design.

[0056] The MEMS microphone sensor in the embodiments of this application, with its unique 3D packaging structure and the coordinated application of multiple innovative technologies, demonstrates broad potential applications in multiple fields. In addition to consumer electronics, in the biomedical field, it can be used in miniature implantable medical devices such as miniature hearing aids and implantable physiological signal monitoring sensors. By optimizing materials to meet biocompatibility requirements and adjusting acoustic performance, it can accurately capture internal human sound signals (such as heartbeats and breathing sounds), facilitating disease diagnosis and health monitoring. In the automotive electronics field, it is suitable for intelligent driving assistance systems. By enhancing electromagnetic interference resistance and temperature stability, and adapting to the interfaces and communication protocols of automotive electronic systems, it can implement voice control and environmental noise monitoring in complex electromagnetic and temperature environments within the vehicle. In the aerospace field, it can be applied to aircraft environmental monitoring. By using special protective materials and structures to withstand extreme environments (such as high altitude, low temperature, and strong radiation), and rigorously testing and calibrating performance, it can achieve high-quality sound acquisition and transmission in confined spaces, providing key support for flight safety and environmental monitoring, and providing strong technical support and new solutions for technological development and product innovation in various fields.

[0057] Example 2 Reference Figure 2 The difference between this embodiment and the first embodiment is that the ASIC chip 3 is flip-chip mounted on the substrate 11 and a conductive hole 4 is provided on the ASIC chip 3 .

[0058] In this embodiment, the conductive vias 4 on the ASIC chip 3 are implemented using through silicon via (TSV) technology, which can be formed by deep silicon etching, wet etching or laser drilling, and the diameter of the conductive vias 4 ranges from several microns to several hundred microns.

[0059] A conductive dielectric layer 41 is disposed within the conductive via 4. In this embodiment, the conductive dielectric layer 41 comprises an insulating layer and a conductive layer. After the conductive via 4 is formed, an insulating layer of SiO2 or other material is first formed, followed by a conductive layer to achieve electrical connectivity between the upper and lower surfaces of the ASIC chip 3. In this embodiment, the conductive layer can be made of a metal material such as copper or aluminum, with a thickness ranging from 0.1 μm to 5 μm.

[0060] The MEMS chip 2 is flip-chip mounted on the ASIC chip 3. The number of vias 4 is equal to and correspondingly arranged with the number of electrodes 25 of the MEMS chip 2, effectively shortening the signal transmission path and reducing the signal loss and electromagnetic interference problems caused by long-distance wiring in the traditional planar layout. At the same time, the via 4 structure provides a stable vertical electrical connection channel, reducing the influence of parasitic capacitance and inductance, thereby improving the integrity and reliability of signal transmission.

[0061] It should be noted that in this embodiment, the diaphragm 24 on the MEMS chip 2 is arranged away from the sound hole 14, which can effectively reduce the direct impact of the external environment on the diaphragm 24 and avoid mechanical damage and signal distortion caused by foreign objects or air flow in the sound hole 14 directly hitting the diaphragm 24. At the same time, this layout optimizes the sound propagation path, enabling the sound wave to be appropriately buffered and diffused after entering the sound cavity 26 and then acting on the diaphragm 24, which helps to improve the sensitivity of the microphone in the low-frequency band and the uniformity of frequency response, thereby enhancing the overall acoustic performance and the stability of the sound signal.

[0062] Embodiment 3 Refer to Figure 3 , the difference between this embodiment and Embodiment 2 is that: the MEMS chip 2 is also provided with vias 4, and a conductive dielectric layer 41 is also arranged in the vias 4, so that the MEMS chip 2 can be electrically connected to the substrate 11 through the vias 4.

[0063] In this embodiment, the vias 4 on the MEMS chip 2 are realized by through-silicon via (TSV) or through-glass via (TGV) technology, and can be formed by deep silicon etching, wet etching or laser drilling processes. Specifically, which technology to use can be selected according to the actual material of the MEMS chip 2.

[0064] The diaphragm 24 on the MEMS chip 2 is arranged close to the sound hole 14, which can effectively shorten the distance for the sound wave to travel from the sound hole 14 to the diaphragm 24, reduce the energy loss and distortion of the sound wave during propagation, thereby helping to ensure that the sound signal is captured and converted in a more efficient and accurate manner, and further improving the overall performance of the microphone.

[0065] The vias 4 on the ASIC chip 3 are aligned with the vias 4 on the MEMS chip 2, which can significantly improve the signal transmission efficiency, reduce the contact resistance, thereby effectively improving the signal integrity, reducing the signal loss and noise interference.

[0066] In the embodiments of the present application, the Flip-chip and TSV or TGV technologies are used to shorten the signal transmission path between the MEMS chip 2 and the ASIC chip 3. In the traditional planar layout, signals need to be transmitted through the wiring on the PCB board, with a long path and being vulnerable to interference. In the present invention, the direct vertical connection between the chips greatly reduces the signal transmission distance, reducing the loss and interference of signals during transmission. For example, when transmitting high-frequency sound signals, the shorter path can reduce signal attenuation and distortion, improving signal integrity.

[0067] At the same time, the vertical electrical connection channels formed by the TSV or TGV technologies reduce problems such as parasitic capacitance and inductance caused by planar wiring. Parasitic capacitance and inductance can affect the frequency response and phase characteristics of signals, and may cause distortion and tone change of sound signals in audio signal processing. By adopting the technology of the present invention, the influence of these parasitic parameters can be effectively reduced, improving the microphone's ability to accurately capture and transmit sound signals, thereby enhancing the sound quality and the accuracy of speech recognition.

[0068] Embodiment 4 Referring to Figure 4 , the difference between this embodiment and Embodiment 1 is that the sound hole 14 is opened on the substrate 11, and it can be opened by means of laser drilling or mechanical drilling.

[0069] The MEMS chip 2 is flip-chip mounted on the substrate 11, and the acoustic cavity 26 of the MEMS chip 2 faces the sound hole 14, and the diaphragm 24 is set away from the sound hole 14, so as to effectively reduce the direct impact of the external environment on the diaphragm 24 and avoid mechanical damage and signal distortion caused by foreign objects or air flow in the sound hole 14 directly hitting the diaphragm 24.

[0070] In this embodiment, conductive holes 4 are opened on the MEMS chip 2, the ASIC chip 3 is flip-chip mounted on the MEMS chip 2, and the number of conductive holes 4 opened on the MEMS chip 2 is equal to and corresponds one by one to the number of electrodes 25, so that the ASIC chip 3 can be electrically connected to the substrate 11 through the conductive holes 4, effectively shortening the signal transmission path and reducing the problems of signal loss and electromagnetic interference caused by long-distance wiring in the traditional planar layout.

[0071] Embodiment 5 Referring to Figure 5 , the difference between this embodiment and Embodiment 4 is that the diaphragm 24 is set close to the sound hole 14, so as to effectively shorten the distance for sound waves to travel from the sound hole 14 to the diaphragm 24, reduce the energy loss and distortion phenomenon of sound waves during propagation, and thus contribute to ensuring that sound signals are captured and converted in a more efficient and accurate manner, thereby improving the overall performance of the microphone.

[0072] Embodiment 6 Reference Figure 6 In this embodiment, the difference from Embodiment 1 is that the diaphragm 24 includes an inner layer film 241 away from the sound hole 14 and an outer layer film 242 close to the sound hole 14. The inner layer film 241 and the outer layer film 242 are arranged in parallel at intervals, and the inner layer film 241 and the outer layer film 242 are arranged between the isolation layer 23 and the electrode 25.

[0073] The elastic modulus of the inner layer film 241 is less than that of the outer layer film 242, so that the inner layer film 241 can generate a large deformation under the action of sound waves to improve the sensitivity to low-frequency sound signals, and the outer layer film 242 can enhance the structural stability and reduce the excessive vibration caused by high-frequency sound signals, thereby improving the high-frequency response characteristics. Furthermore, through the synergistic effect of the inner layer film 241 and the outer layer film 242, the acoustic performance of the microphone is effectively improved, and high-fidelity audio acquisition with a wider frequency band is realized.

[0074] Embodiment 7 Reference Figure 7 In this embodiment, the difference from Embodiment 1 is that a plurality of limiting protrusions 121 are arranged in the housing 12. The plurality of limiting protrusions 121 are arranged at intervals, and the plurality of limiting protrusions 121 respectively abut against the circumferences of the MEMS chip 2 and the ASIC chip 3.

[0075] The arrangement of the limiting protrusions 121 can accurately position the MEMS chip 2 and the ASIC chip 3, prevent the chips from shifting or tilting in the packaging cavity 13, and thus improve the stability of the packaging structure. At the same time, the plurality of limiting protrusions 121 are arranged at intervals, which can effectively disperse the stress, avoid chip damage caused by stress concentration, and further improve the packaging reliability. In addition, the limiting protrusions 121 respectively abut against the circumferences of the MEMS chip 2 and the ASIC chip 3, ensuring the position accuracy of the chips in the longitudinal stacking state, helping to optimize the signal transmission path, reducing signal loss, and improving the acoustic performance.

[0076] The above are all the preferred embodiments of this application, and the protection scope of this application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A MEMS microphone sensor, characterized in that: The invention comprises a packaging substrate (1), a MEMS chip (2) and an ASIC chip (3); the packaging substrate (1) is provided with an acoustic hole (14); the MEMS chip (2) and the ASIC chip (3) are stacked longitudinally in the packaging substrate (1) and are electrically connected to the packaging substrate (1) respectively; the MEMS chip (2) is arranged corresponding to the acoustic hole (14).

2. The MEMS microphone sensor according to claim 1, wherein: The packaging base (1) comprises a substrate (11) and a shell (12) arranged on the substrate (11); a packaging cavity (13) is formed between the shell (12) and the substrate (11); the ASIC chip (3) is located in the packaging cavity (13) and is electrically connected to the substrate (11); the MEMS chip (2) is flip-chip mounted on a side of the ASIC chip (3) facing away from the substrate (11); and the sound hole (14) is opened on the shell (12) and arranged close to the MEMS chip (2).

3. The MEMS microphone sensor according to claim 2, wherein: The ASIC chip (3) is flip-mounted on the substrate (11), a conductive hole (4) is provided on the ASIC chip (3), and the MEMS chip (2) is electrically connected to the substrate (11) through the conductive hole (4).

4. The MEMS microphone sensor according to claim 2, wherein: The ASIC chip (3) is flip-mounted on the substrate (11); conductive holes (4) are respectively provided on the ASIC chip (3) and the MEMS chip (2); and the MEMS chip (2) is electrically connected to the substrate (11) through the conductive holes (4).

5. The MEMS microphone sensor according to claim 4, wherein: The conductive holes (4) on the ASIC chip (3) are aligned with the conductive holes (4) on the MEMS chip (2).

6. The MEMS microphone sensor according to claim 1, wherein: The packaging base (1) comprises a substrate (11) and a shell (12) arranged on the substrate (11); a packaging cavity (13) is formed between the shell (12) and the substrate (11); the MEMS chip (2) is located in the packaging cavity (13) and is flip-mounted on the substrate (11); a conductive hole (4) is provided through the MEMS chip (2); the ASIC chip (3) is flip-mounted on a side of the MEMS chip (2) away from the substrate (11) and is electrically connected to the substrate (11) through the conductive hole (4); and the acoustic hole (14) is provided on the substrate (11) and is provided corresponding to the MEMS chip (2).

7. The MEMS microphone sensor according to claim 2 or 6, characterized in that: A plurality of limiting protrusions (121) are provided in the housing (12), the plurality of limiting protrusions (121) are spaced apart from each other, and the plurality of limiting protrusions (121) respectively contact the peripheral sides of the MEMS chip (2) and the ASIC chip (3).

8. The MEMS microphone sensor according to claim 1, wherein: The MEMS chip (2) comprises a substrate (21) and a through-hole back plate (22), an isolation layer (23), a diaphragm (24) and an electrode (25) sequentially arranged on the substrate (21); an acoustic cavity (26) is formed between the through-hole back plate (22) and the substrate (21); the acoustic cavity (26) is arranged corresponding to the acoustic hole (14); and the electrode (25) is used for electrically connecting to the packaging base (1).

9. The MEMS microphone sensor according to claim 8, wherein: The diaphragm (24) is arranged close to or far away from the sound hole (14).

10. The MEMS microphone sensor according to claim 8, characterized in that: The diaphragm (24) includes an inner membrane (241) away from the sound hole (14) and an outer membrane (242) close to the sound hole (14), the inner membrane (241) and the outer membrane (242) are arranged in parallel and spaced apart, the inner membrane (241) and the outer membrane (242) are arranged between the isolation layer (23) and the electrode (25), and the elastic modulus of the inner membrane (241) is smaller than the elastic modulus of the outer membrane (242).

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