A MEMS device, a manufacturing method thereof, and an electronic device

Abstract

A MEMS device and a manufacturing method thereof and an electronic device, the method comprising: providing a substrate, a device structure layer is formed on the substrate, the device structure layer comprises spaced first diaphragm and second diaphragm, the first diaphragm is away from the substrate, the second diaphragm is connected with the substrate, the sacrificial layer is formed between the first diaphragm and the second diaphragm, the surface of the first diaphragm comprises a first region and a second region, the first region is located at the edge of the surface of the first diaphragm, and the first region surrounds the second region; forming a patterned first photoresist layer on the surface of the first diaphragm, wherein the first photoresist layer exposes the second region and covers the first region, and the first photoresist layer has a first thickness in the first region; forming a patterned second photoresist layer in the second region, the second photoresist layer has a second thickness, wherein the second thickness is less than the first thickness; etching the first diaphragm with the second photoresist layer as a mask to form a plurality of release holes, the release holes penetrate through the first diaphragm and expose the sacrificial layer.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically to a MEMS device and its manufacturing method, and an electronic device. Background Technology

[0002] MEMS (Micro-Electro-Mechanical System) devices are components manufactured using microelectronics and micromachining technologies. They are characterized by miniaturization, integration, intelligence, multifunctionality, and low cost. A dual-diaphragm microphone is a type of microphone manufactured using MEMS technology. It consists of two adjacent diaphragms. When sound waves act on the diaphragms, different capacitance changes occur, which are then converted into electrical signals. Compared to single-diaphragm microphones, dual-diaphragm microphones have higher sensitivity and a signal-to-noise ratio (>70dB), can better capture sound details and reduce background noise, improving call quality and speech recognition performance.

[0003] One of the most challenging steps in the manufacturing process of dual-diaphragm microphones is etching the release hole used for sacrificial layer release. This process can easily damage the film layer at the edge of the device's structural layers, ultimately affecting the device's structure and performance.

[0004] Therefore, it is necessary to propose a new method for manufacturing MEMS devices and MEMS devices and electronic devices to at least partially solve the above problems. Summary of the Invention

[0005] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This summary section is not intended to limit the key and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0006] To address the existing problems, this application provides a method for manufacturing a MEMS device, comprising: providing a substrate; forming a device structure layer on the substrate, the device structure layer including a first diaphragm and a second diaphragm spaced apart, the first diaphragm being away from the substrate, the second diaphragm being connected to the substrate; forming a sacrificial layer between the first diaphragm and the second diaphragm; the surface of the first diaphragm including a first region and a second region, the first region being located at the edge of the surface of the first diaphragm and surrounding the second region; forming a patterned first photoresist layer on the surface of the first diaphragm, wherein the first photoresist layer exposes the second region and covers the first region, the first photoresist layer having a first thickness in the first region; and forming a patterned second photoresist layer in the second region, the second photoresist layer having a second thickness, wherein the second thickness is less than the first thickness.

[0007] The first diaphragm is etched using the second photoresist layer as a mask to form a plurality of release holes, which penetrate the first diaphragm and expose the sacrificial layer.

[0008] For example, the device structure layer further includes: a sidewall portion, the first diaphragm, the second diaphragm and the sidewall portion together forming an inner cavity, the sacrificial layer filling the inner cavity, and the first photoresist layer also covering the sidewall portion.

[0009] For example, the first thickness is greater than 4.5 μm, and the second thickness is less than 2 μm.

[0010] For example, the first diaphragm includes a first insulating layer and an electrode layer, the electrode layer covering the first insulating layer, the release hole being formed in the first insulating layer, and the sidewall portion including a second insulating layer, the second insulating layer and the first insulating layer being made of the same insulating material layer.

[0011] For example, the device structure layer further includes:

[0012] A backplate is disposed between the first diaphragm and the second diaphragm, a first cavity is formed between the backplate and the first diaphragm, and a second cavity is formed between the backplate and the second diaphragm. The inner cavity includes the first cavity and the second cavity.

[0013] A support rod is formed in the cavity and extends through the back plate and is connected to the first diaphragm and the second diaphragm.

[0014] For example, after the step of etching the first diaphragm using the second photoresist layer as a mask, the method for manufacturing the MEMS device further includes: removing the first photolithography layer and the second photoresist layer.

[0015] For example, after the step of etching the first diaphragm using the second photoresist layer as a mask, the method for manufacturing the MEMS device further includes: removing a portion of the sacrificial layer via the release hole.

[0016] This application also provides a MEMS device, which is manufactured using any of the above-described MEMS device manufacturing methods.

[0017] For example, the MEMS device includes a dual-diaphragm microphone.

[0018] This application also provides an electronic device, including the aforementioned MEMS device.

[0019] According to the MEMS device manufacturing method provided in this application, by using two photoresist layers of different thicknesses, it is possible to open the release hole while protecting the edge film layer of the device structure layer from damage during the etching process, thus avoiding negative impacts on the structure and performance of the device. Attached Figure Description

[0020] The following drawings, which are incorporated herein by reference and are used to understand this application, illustrate embodiments of the invention and their descriptions to explain the principles of the invention.

[0021] Figure 1 A schematic diagram of the cross-sectional structure of a device obtained by a manufacturing method of a MEMS device according to related technologies is shown.

[0022] Figure 2 A schematic flowchart illustrating a method for manufacturing a MEMS device according to an embodiment of this application is shown;

[0023] Figure 3A and 3B A top view of the device obtained by sequentially implementing a method for manufacturing a MEMS device according to an embodiment of this application is shown.

[0024] Figure 4A and 4B A schematic cross-sectional view of a device obtained by sequentially implementing a method for manufacturing a MEMS device according to an embodiment of this application is shown.

[0025] Figure 5 A schematic cross-sectional view of a device obtained by sequentially implementing a method for manufacturing a MEMS device according to an embodiment of this application is shown.

[0026] In the attached diagram,

[0027] MEMS device 100, first diaphragm 110, second diaphragm 120, sidewall portion 130, photoresist layer 111

[0028] MEMS device 300, first diaphragm 310, first insulating layer 3101, electrode layer 3102, first region 311, second region 312, first photoresist layer 3110, second photoresist layer 3120, opening 3121, release hole 3122, second diaphragm 320, substrate 301, backplate 302, sidewall portion 330, support rod 303, sacrificial layer 304, first thickness d1, second thickness d2. Detailed Implementation

[0029] The following description provides numerous specific details to offer a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with this application.

[0030] It should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this application to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0031] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0032] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below” or “under” the other element or feature will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0033] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0034] Currently, a key and challenging step in the manufacturing process of dual-diaphragm microphones is etching the release hole. A schematic diagram of the cross-sectional structure of the MEMS device 100 obtained based on the manufacturing methods of related MEMS devices is shown below. Figure 1 As shown, due to the requirements of the dual-diaphragm microphone structure, the height of the dual diaphragms (i.e., the distance between the first diaphragm 110 and the second diaphragm 120) ranges from 10μm to 12μm, and the diameter of the release hole ranges from 0.3μm to 0.6μm. Therefore, the photoresist layer 111 used to etch the release hole must be thin. However, this results in insufficient protection of the edges and sidewalls 130 of the first diaphragm 110 by the photoresist layer (e.g., ...). Figure 1 As shown, etching the release hole will damage the edge and sidewall 130 of the first diaphragm 110, ultimately affecting the structure and performance of the MEMS device.

[0035] To address the technical problems existing in related technologies, this application proposes a method for manufacturing MEMS devices. This method can protect the edges and sidewalls of the diaphragm of the MEMS device without altering the original structural design of the MEMS device. The following is a combination of... Figures 2 to 4B Further detailed description and explanation, in which, Figure 2A schematic flowchart illustrating a method for manufacturing a MEMS device according to an embodiment of this application is shown; Figure 3A and 3B A top view of the device obtained by sequentially implementing a method for manufacturing a MEMS device according to an embodiment of this application is shown. Figure 4A and 4B A schematic cross-sectional view of a device obtained by sequentially implementing a method for manufacturing a MEMS device according to an embodiment of this application is shown.

[0036] In one embodiment, such as Figure 2 As shown, the method for manufacturing a MEMS device provided in this application includes:

[0037] Step S1: Provide a substrate, and form a device structure layer on the substrate. The device structure layer includes a first diaphragm and a second diaphragm spaced apart. The first diaphragm is away from the substrate, and the second diaphragm is connected to the substrate. A sacrificial layer is formed between the first diaphragm and the second diaphragm. The surface of the first diaphragm includes a first region and a second region. The first region is located at the edge of the surface of the first diaphragm and surrounds the second region.

[0038] Step S2: A patterned first photoresist layer is formed on the surface of the first diaphragm, wherein the first photoresist layer exposes the second region and covers the first region, and the first photoresist layer has a first thickness in the first region;

[0039] Step S3: A patterned second photoresist layer is formed in the second region, the second photoresist layer having a second thickness, wherein the second thickness is less than the first thickness;

[0040] Step S4: Use the second photoresist layer as a mask to etch the first diaphragm to form a plurality of release holes, the release holes penetrating the first diaphragm and exposing the sacrificial layer.

[0041] Specifically, Figures 3A to 4B A schematic cross-sectional view of a MEMS device 300 obtained by sequentially implementing a manufacturing method for a MEMS device according to an embodiment of this application is shown. It should be noted that the accompanying drawings in this application only show a portion of the structure of the MEMS device 300 and are not intended to limit the scope of protection of this application. Figures 3A to 4BAs shown, a device structure layer is formed on a substrate 301. The device structure layer includes a first diaphragm 310 and a second diaphragm 320 spaced apart. The first diaphragm 310 is away from the substrate 301, and the second diaphragm 320 is connected to the substrate 301. A sacrificial layer 304 is formed between the first diaphragm 310 and the second diaphragm 320. The surface of the first diaphragm 310 includes a first region 311 and a second region 312. The first region 311 is located at the edge of the surface of the first diaphragm 310 and surrounds the second region 312. The device structure layer also includes a sidewall portion 330. The first diaphragm 310, the second diaphragm 320 and the sidewall portion 330 together form an inner cavity. The sacrificial layer 304 fills the inner cavity. The first photoresist layer 3110 also covers the sidewall portion 330.

[0042] In some embodiments, the substrate 301 may be made of at least one of the following materials: germanium, silicon germanide, silicon carbide, silicon on insulator (SOI), silicon on insulator (SSOI), silicon on insulator (S-SiGeOI), silicon on insulator (SiGeOI), and germanium on insulator (GeOI).

[0043] In some embodiments, the materials of the first diaphragm 310 and the second diaphragm 320 include at least one of the following materials: the diaphragm material can be various conductive materials, such as a single metal such as Al, W or Cu or an alloy formed of at least two metals, or doped polycrystalline silicon, or doped amorphous silicon, etc.

[0044] In one embodiment, the first diaphragm 310 includes a first insulating layer 3101 and an electrode layer 3102, the electrode layer 3102 covering the first insulating layer 3101, the electrode layer 3102 serving as the lead-out electrode of the first diaphragm, and the first insulating layer 3101 serving as the insulating layer. For example, the material of the first insulating layer 3101 includes at least one of the following: silicon nitride, silicon carbide, or any other suitable insulating material.

[0045] For example, the sidewall portion 330 is used to form the sidewall of the inner cavity and can also be used to insulate the first diaphragm 310 and the second diaphragm 320 from each other. The sidewall portion 330 may include a second insulating layer. The second insulating layer and the first insulating layer 3101 are made of the same insulating material layer or different insulating materials. For example, the material of the second insulating layer includes at least one of the following materials: silicon nitride, silicon carbide, or any other suitable insulating material. In a specific embodiment of this application, the method of forming the first insulating layer 3101 and the sidewall portion 330 includes: depositing an insulating material layer to cover the surface of the sacrificial layer and the sidewall, wherein the insulating material layer on the surface of the sacrificial layer serves as the first insulating layer, and the insulating material layer on the sidewall serves as the second insulating layer.

[0046] In some embodiments, such as Figures 3A to 4B As shown, the device structure layer also includes a backplate 302 and a support rod 303, wherein: the backplate 302 is disposed between the first diaphragm 310 and the second diaphragm 320, a first cavity is formed between the backplate 302 and the first diaphragm 310, and a second cavity is formed between the backplate 302 and the second diaphragm, the inner cavity shown includes the first cavity and the second cavity; the support rod 303 is formed in the inner cavity, penetrates the backplate 302 and is connected to the first diaphragm 310 and the second diaphragm 320. For example, a sacrificial layer 304 fills the first cavity and the second cavity.

[0047] For example, the backplane 302 adopts a three-layer composite layer. The lower layer of the three-layer composite layer is the lower structural layer of the backplane, the middle layer of the three-layer composite layer is the conductive layer of the backplane, and the upper layer of the three-layer composite layer is the upper structural layer of the backplane. The sidewalls of the conductive layer of the backplane are covered by the upper structural layer of the backplane. Both the lower structural layer and the upper structural layer of the backplane are made of insulating material. The conductive layer of the backplane can be made of, for example, polycrystalline silicon or amorphous silicon material, and the upper structural layer and the lower structural layer of the backplane can be made of, for example, silicon nitride material.

[0048] For example, at least one support rod 303 is provided between the first diaphragm 310 and the second diaphragm 320. The support rod 303 passes through a through hole in the back plate 302 and is connected to the first diaphragm 310 and the second diaphragm 320. The first diaphragm 310 and the second diaphragm 320 are electrically insulated from the support rod 303, so that the first diaphragm 310 and the second diaphragm 320 move synchronously after being subjected to external force.

[0049] For example, the sacrificial layer 304 includes at least one of the following materials: silicon oxide, borosilicate glass, phosphosilicate glass, borophosphosilicate glass, etc. The sacrificial layer 304 is deposited by thermal oxidation or chemical vapor deposition (CVD). Specifically, when the sacrificial layer 304 is silicon oxide, thermal oxidation or CVD deposition can be used, and when the sacrificial layer 304 is borosilicate glass, phosphosilicate glass or borophosphosilicate glass, CVD deposition is used.

[0050] The above-mentioned device structure layer can be formed by any suitable method. In a specific example, a second diaphragm 320, a first sacrificial layer, a backplate 302, and a second sacrificial layer can be formed sequentially on the surface of a substrate. Then, an opening is formed through the second sacrificial layer, the backplate 302, and the first sacrificial layer, exposing the second diaphragm 320. The opening is filled with a filling material such as polysilicon to form a support rod. Afterward, a portion of the second diaphragm 320, the first sacrificial layer, the backplate 302, and the second sacrificial layer on the edge region of the substrate can be removed by etching, for example, to allow the material to flow out of a portion of the substrate surface. Then, a first insulating layer 3101 covering the surface of the second sacrificial layer, and a second insulating layer covering the sidewalls of the second diaphragm 320, the first sacrificial layer, the backplate 302, and the second sacrificial layer are formed. The insulating material layer may also cover a portion of the substrate surface. The first insulating layer and the second insulating layer can be made of the same insulating material layer. Then, an electrode material layer, such as a polysilicon layer, is formed on the surface of the first insulating layer, and the electrode material layer is patterned to form the electrode layer 3102.

[0051] In some embodiments, the second diaphragm 320 may include a second electrode layer and a third insulating layer stacked from bottom to top, wherein the second electrode layer is a patterned electrode layer, and a back cavity is also formed in the substrate, the back cavity penetrating the substrate and exposing a portion of the second diaphragm 320, wherein the back cavity and the inner cavity at least partially overlap vertically.

[0052] Specifically, such as Figure 3A and 4A As shown, a patterned first photoresist layer 3110 is formed on the first surface of the device structure layer, wherein the first photoresist layer 3110 exposes the second region 312 and covers the first region 311, the first photoresist layer 3110 extends to at least a portion of the substrate 301 and covers the sidewall portion 330, wherein the first photoresist layer 3110 protects the edge and sidewall portion 330 of the first diaphragm 310 by covering the first region 311 and the sidewall portion 330.

[0053] Optionally, the first photoresist layer 3110 has a first thickness d1 in the first region 311, the first thickness d1 being greater than 4.5 μm, such as 4.6 μm, 4.8 μm, 5.0 μm, 5.2 μm, 5.4 μm, or other suitable dimensions.

[0054] Optionally, the first photoresist layer 3110 has a third thickness on the surface of the sidewall portion 330, the third thickness being greater than 4.5 μm, such as 4.6 μm, 4.8 μm, 5.0 μm, 5.2 μm, 5.4 μm, or other suitable dimensions.

[0055] In some embodiments, such as Figure 3B and 4BAs shown, after a patterned first photoresist layer 3110 is formed on the first surface of the device structure layer, a patterned second photoresist layer 3120 is formed in the second region 312. The second photoresist layer 3120 has a second thickness d2, wherein the second thickness d2 is less than the first thickness d1.

[0056] Optionally, the second thickness d2 is less than 2 μm, for example, 1.8 μm, 1.6 μm, 1.4 μm, 1.2 μm, 1.0 μm, or other suitable dimensions. Furthermore, the first thickness d1 of the first photoresist layer 3110 is greater than the second thickness d2 of the second photoresist layer 3120. By using photoresist layers of different thicknesses, the thicker first photoresist layer 3110 is used to protect the edge of the diaphragm, and the thinner second photoresist layer 3120 is used for the subsequent etching of the release hole 3122, thereby avoiding the problem that a single thin photoresist layer cannot protect the edge and sidewall of the diaphragm during the etching process.

[0057] Continue to refer to Figure 3B and Figure 4B The second photoresist layer 3120 is provided with a plurality of openings 3121, each opening 3121 defining the position of a predetermined release hole 3122, and the diameter of the opening 3121 is equal to the diameter of the release hole 3122.

[0058] For example, the release hole 3122 can be etched using any suitable method, such as hydrofluoric acid vapor etching or wet etching, to remove the first diaphragm 310 exposed through the second photoresist layer 3120. Taking hydrofluoric acid vapor etching to remove the insulating layer as an example, hydrofluoric acid vapor etching is a process that uses hydrofluoric acid vapor to etch a silicon wafer, effectively avoiding adhesion problems and improving MEMS performance. The basic principle of this process is: the device substrate is placed in a sealed reaction chamber, and hydrofluoric acid vapor is generated by heating. The hydrofluoric acid vapor reacts with an insulating layer, such as silicon dioxide, on the substrate surface to generate water and hexafluorosilicic acid. The hexafluorosilicic acid reacts with silicon on the device surface to generate water and silicon tetrafluoride. Silicon tetrafluoride is a volatile gas that can be discharged from the reaction chamber, achieving the etching of the insulating layer. Since the first photoresist has a relatively thick first thickness, it covers the sidewalls and edge regions of the device structure layer. Therefore, during the formation of the release hole, it protects the film layers on the sidewalls (e.g., the sidewall portion) and the film layers in the edge regions (e.g., the first insulating layer of the first diaphragm) of the device structure layer, preventing etching from damaging these film layers.

[0059] In some embodiments, such as Figure 5As shown, the release hole 3122 penetrates the first diaphragm 310 and exposes the sacrificial layer 304. After the etching step, the MEMS device manufacturing method further includes removing a portion of the sacrificial layer 304 via the release hole 3122. Optionally, a portion of the sacrificial layer 304 located at the edge region of the first diaphragm may be retained to support the first diaphragm. The sidewall portion may also include the retained sacrificial layer and the edge region of the backplate. MEMS devices typically require one or more sacrificial layers to achieve structural suspension or isolation to form cavities. However, after the device is completed, the sacrificial layer needs to be removed to ensure normal device operation. Examples of commonly used methods for removing sacrificial layers include: Wet etching: Wet etching is a method that uses liquid chemical reagents to dissolve or react with the sacrificial layer. Dry etching: Dry etching is a method that uses plasma or reactive gases to etch away the sacrificial layer. Supercritical fluid: Supercritical fluid is a state of matter between gas and liquid, characterized by high permeability, high solubility, and low surface tension. Supercritical fluids can be used to remove the sacrificial layer while simultaneously cleaning away residues, preventing structural collapse or adhesion. There are various methods for removing the sacrificial layer from MEMS devices, and those skilled in the art can select the appropriate method based on the specific device structure and requirements.

[0060] In some embodiments, after performing the etching step of the release hole, the method for manufacturing a MEMS device further includes removing the first photolithography layer and the second photoresist layer 3120. Photoresist is a photosensitive material used in photolithography processes. It can undergo chemical changes under ultraviolet light or X-ray irradiation to form the desired pattern. Photoresist removal is a crucial step in the photolithography process, affecting the quality and efficiency of subsequent processes. For example, commonly used photoresist removal processes can be employed, such as wet removal, dry removal, or thermal removal. Wet removal utilizes organic solvents or alkaline solutions to dissolve or strip the photoresist; dry removal utilizes plasma or oxide vapors to oxidize or decompose the photoresist; and thermal removal utilizes a high-temperature heat source to pyrolyze or carbonize the photoresist. Various photoresist removal processes are available, and those skilled in the art can select an appropriate method based on the specific substrate material and device requirements.

[0061] It is worth mentioning that the step of removing part of the sacrificial layer 304 through the release hole 3122 can be performed first, and then the step of removing the first photolithography layer and the second photoresist layer 3120 can be performed. Alternatively, the step of removing the first photolithography layer and the second photoresist layer 3120 can be performed first, and then the step of removing part of the sacrificial layer 304 through the release hole 3122 can be performed.

[0062] In some embodiments, the method of this application may further include the following steps: depositing an insulating material layer and filling the release pores.

[0063] It is worth mentioning that this application mainly uses a dual-diaphragm microphone as an example to describe the method of this application. However, it is understood that other MEMS devices that need to form a release hole and protect the sidewalls can also be applied to the method of this application. The above method is only an example and there is no strict order limit. Under the premise of not contradicting each other, they can be performed alternately or in different orders.

[0064] This concludes the description of some steps of the method in this application. Other steps may be included to form a complete device, which will not be elaborated here.

[0065] The manufacturing method of MEMS devices provided in this application has the following beneficial effects: without changing the original design of the MEMS device, by using two consecutive photolithography processes and combining two types of photoresist with different thicknesses, it is possible to open the release hole and protect the edge and sidewall of the diaphragm from damage during the etching process, thereby improving the reliability, performance and service life of the MEMS device.

[0066] This application also provides a MEMS device, which can be manufactured using the aforementioned MEMS device manufacturing method. The MEMS device provided in this application, due to the use of the aforementioned MEMS device manufacturing method, exhibits better performance, reliability, and lifespan.

[0067] For example, the MEMS device provided in this application includes a dual-diaphragm microphone, which is a capacitive microphone that uses two movable diaphragms to realize the differential readout process and has advantages such as high signal-to-noise ratio, low distortion, and high acoustic overload point.

[0068] The main applications of dual-diaphragm microphones in electronic devices include: Remote speech recognition: Dual-diaphragm microphones can achieve high speech recognition rates at distances exceeding seven meters, making them ideal for televisions, smart home appliances, and other AIoT (Artificial Intelligence of Things) scenarios. Active noise cancellation: Dual-diaphragm microphones provide high-quality audio signal input for active noise cancellation systems, significantly reducing environmental and background noise, making it easier for the system to identify identifiable features. Voice wake-up, voiceprint recognition, and sound source localization: Dual-diaphragm microphones can provide high-definition and realistic audio signals, improving the accuracy and efficiency of these functions. High-end AI speech recognition: Dual-diaphragm microphones can achieve zero intrinsic mechanical noise, greatly improving the signal-to-noise ratio to over 72dB, and can be applied in high-end fields such as AI speech recognition in measuring instruments, industrial manufacturing, music, security, and robotics. In conclusion, dual-diaphragm microphones are electronic devices with broad application prospects, providing high-quality audio input and output for various voice-related functions.

[0069] This application also provides an electronic device including the above-described MEMS device, wherein the MEMS device is the MEMS device described in the above embodiments, or a MEMS device manufactured according to the above-described MEMS device manufacturing method.

[0070] For example, a dual-diaphragm microphone is a high-performance condenser microphone that provides high-quality audio input and output for various voice-related functions. Examples of electronic devices that can incorporate dual-diaphragm microphones include: Smartphones: Smartphones are the largest market for microphones, and dual-diaphragm microphones can improve the performance of functions such as voice recognition, video recording, and voiceprint unlocking. TWS Bluetooth Earphones: TWS Bluetooth earphones require high signal-to-noise ratio microphones to achieve functions such as active noise cancellation, far-field communication, and environmental awareness. Dual-diaphragm microphones can provide high-quality audio signal input to active noise cancellation systems, greatly reducing environmental and background noise, making it easier for the system to identify identifiable features. Smart Speakers: Smart speakers require high signal-to-noise ratio microphones to achieve functions such as remote voice recognition, voice wake-up, and sound source localization. Dual-diaphragm microphones can achieve high voice recognition rates at distances of over seven meters, making them ideal for televisions, smart home appliances, and other AIoT scenarios. Electronic devices can also include laptops, tablets, digital cameras, etc., which can also be equipped with dual-diaphragm microphones to achieve high-quality video calls, recording, and shooting functions. Dual-diaphragm microphones can provide high-definition and realistic sound signals, which helps improve the accuracy and efficiency of these functions. In summary, the electronic device provided in this application, due to the use of the aforementioned MEMS devices, has better performance, reliability, and lifespan.

[0071] This application has been described through the above embodiments. However, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit this application to the scope of the described embodiments. Furthermore, those skilled in the art will understand that this application is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of this application, all of which fall within the scope of protection claimed in this application. The scope of protection of this application is defined by the appended claims and their equivalents.

Claims

1. A method for manufacturing a MEMS device, characterized in that, include: A substrate is provided, on which a device structure layer is formed, the device structure layer including a first diaphragm and a second diaphragm spaced apart, the first diaphragm being away from the substrate, the second diaphragm being connected to the substrate, a sacrificial layer being formed between the first diaphragm and the second diaphragm, the surface of the first diaphragm including a first region and a second region, the first region being located at the edge of the surface of the first diaphragm, the first region surrounding the second region; A patterned first photoresist layer is formed on the surface of the first diaphragm, wherein the first photoresist layer exposes the second region and covers the first region, and the first photoresist layer has a first thickness in the first region; A patterned second photoresist layer is formed in the second region, the second photoresist layer having a second thickness, wherein the second thickness is less than the first thickness; The first diaphragm is etched using the second photoresist layer as a mask to form a plurality of release holes, which penetrate the first diaphragm and expose the sacrificial layer.

2. The method for manufacturing a MEMS device according to claim 1, characterized in that, The device structure layer also includes: The sidewall portion, the first diaphragm, the second diaphragm and the sidewall portion together form an inner cavity, the sacrificial layer fills the inner cavity, and the first photoresist layer also covers the sidewall portion.

3. The method for manufacturing a MEMS device according to claim 1, characterized in that, The first thickness is greater than 4.5 μm, and the second thickness is less than 2 μm.

4. The method for manufacturing a MEMS device according to claim 2, characterized in that, The first diaphragm includes a first insulating layer and an electrode layer, the electrode layer covering the first insulating layer, the release hole being formed in the first insulating layer, and the sidewall portion including a second insulating layer, the second insulating layer and the first insulating layer being made of the same insulating material layer.

5. The method for manufacturing a MEMS device according to claim 2, characterized in that, The device structure layer also includes: A backplate is disposed between the first diaphragm and the second diaphragm, a first cavity is formed between the backplate and the first diaphragm, and a second cavity is formed between the backplate and the second diaphragm. The inner cavity includes the first cavity and the second cavity. A support rod is formed in the cavity and extends through the back plate and is connected to the first diaphragm and the second diaphragm.

6. The method for manufacturing a MEMS device according to claim 1, characterized in that, After the step of etching the first diaphragm using the second photoresist layer as a mask, the method for manufacturing the MEMS device further includes: removing the first photoresist layer and the second photoresist layer.

7. The method for manufacturing a MEMS device according to claim 6, characterized in that, After the step of etching the first diaphragm using the second photoresist layer as a mask, the method for manufacturing the MEMS device further includes: removing a portion of the sacrificial layer via the release hole.

8. A MEMS device, characterized in that, The MEMS device is manufactured using the method described in any one of claims 1 to 7.

9. The MEMS device of claim 8, wherein the MEMS device comprises a dual-diaphragm microphone.

10. An electronic device, characterized in that, Includes the MEMS devices as described in claim 8 or 9.

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