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

Abstract

A MEMS device, a preparation method of the MEMS device and an electronic device, the device comprising: a first substrate, a surface of the first substrate being provided with a groove and a dielectric layer filling the groove and covering the first substrate, the dielectric layer being provided with a first electrode plate layer, the first electrode plate layer being provided with a functional layer, part of the functional layer being suspended above the first electrode plate layer; a second substrate, a recess being formed in the second substrate, one side of the first substrate on which the functional layer is formed being combined with one side of the second substrate on which the recess is formed. The MEMS device of the present application forms a groove in the first substrate, increases the distance between the first electrode plate and the first substrate by increasing the first electrode plate, thereby effectively reducing the ground capacitance, improving the resolution of the MEMS device and being simple in structure and low in manufacturing cost.

Description

Technical Field

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

[0002] MEMS (Micro Electro Mechanical Systems) involve multiple disciplines and engineering technologies, including physics, semiconductors, optics, electronic engineering, chemistry, materials engineering, mechanical engineering, and bioengineering, opening up broad applications for intelligent systems, wearable devices, smart homes, automobiles, and drones. Common MEMS devices include pressure sensors, inertial sensors, and optical sensors.

[0003] In MEMS inertial sensor structures, the capacitance to ground directly affects the device's bandwidth and noise density, and directly determines the sensor's minimum detectable limit (resolution). A smaller capacitance to ground results in higher resolution for the MEMS device. In existing MEMS devices, one approach is to reduce the capacitance to ground by lowering the dielectric constant of the insulating medium between the electrode plate and the substrate. However, the difficulty in obtaining materials with low dielectric constants increases the manufacturing cost of MEMS devices. Another approach is to reduce the capacitance to ground by reducing the area of ​​the electrode plate facing the substrate. This makes the MEMS device manufacturing process complex and excessively expensive. Summary of the Invention

[0004] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. The summary section of this invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0005] To address the existing problems, this application provides a MEMS device comprising: a first substrate, wherein a trench is formed on the surface of the first substrate and a dielectric layer is formed to fill the trench and cover the first substrate, a first electrode layer is formed on the dielectric layer, a functional layer is formed on the first electrode layer, and a portion of the functional layer is suspended above the first electrode layer; and a second substrate, wherein a groove is formed in the second substrate, and the side of the first substrate where the functional layer is formed is combined with the side of the second substrate where the groove is formed.

[0006] For example, there are multiple trenches, which are spaced apart within the first substrate, wherein the multiple trenches are opposite to at least a portion of the first electrode layer, and the trenches at least partially correspond to the functional layer.

[0007] For example, the projection of the plurality of trenches onto the plane of the substrate surface is a grid or a plurality of spaced stripes.

[0008] For example, the number of the trenches is one, one trench is opposite to at least a portion of the first electrode layer, and the trench corresponds at least partially to the functional layer.

[0009] For example, when there are multiple trenches, the dielectric layer includes a first sub-dielectric layer that fills the trenches and a second sub-dielectric layer that covers the surface of the first substrate and the first sub-dielectric layer, wherein the width of each trench is less than or equal to half the thickness of the second sub-dielectric layer.

[0010] For example, the groove of the second substrate has a second electrode layer disposed on the surface facing the first substrate.

[0011] For example, the material of the first electrode layer includes polycrystalline silicon, and the material of the second electrode layer includes polycrystalline silicon.

[0012] This application also provides a method for fabricating a MEMS device, comprising: providing a first substrate; forming a trench in the first substrate, the trench extending from the surface of the first substrate into the first substrate; forming a dielectric layer to cover the surface of the first substrate and fill the trench; forming a first electrode layer on the dielectric layer; forming a functional layer above the first electrode layer, a portion of the functional layer being suspended above the first electrode layer; providing a second substrate, in which a groove is formed; and combining one side of the first substrate where the functional layer is formed with one side of the second substrate where the groove is formed.

[0013] For example, forming a functional layer above the first electrode layer includes: forming a sacrificial layer above the first electrode layer, forming a functional material layer on the sacrificial layer; removing a portion of the functional material layer to form a functional layer, removing a portion of the sacrificial layer to form a cavity on the first substrate, such that a portion of the functional layer is suspended above the first electrode layer.

[0014] For example, forming a trench in the first substrate includes: when the depth of the predetermined trench is less than a preset threshold, performing dry etching and / or wet etching on the first substrate to form the trench; and when the depth of the predetermined trench is greater than or equal to the preset threshold, performing deep silicon etching on the first substrate to form the trench.

[0015] This application also provides an electronic device, including the MEMS device described above.

[0016] The MEMS device of this application embodiment has trenches and filled trenches on the surface of a first substrate and a dielectric layer covering the first substrate. A first electrode layer is disposed on the dielectric layer, and a functional layer is disposed on the first electrode layer. Part of the functional layer is suspended above the first electrode layer. It also has a second substrate, in which a groove is formed. The side of the first substrate where the functional layer is formed is combined with the side of the second substrate where the groove is formed. By forming trenches in the first substrate, this application increases the distance between the first electrode layer and the first substrate, thereby effectively reducing the ground capacitance of the MEMS device, improving the resolution of the MEMS device, and having a simple structure and low manufacturing cost. Attached Figure Description

[0017] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0018] Figure 1 A schematic cross-sectional view of a MEMS device according to an embodiment of this application is shown.

[0019] Figure 2 A schematic cross-sectional view of a MEMS device according to an embodiment of this application is shown on the plane containing the first surface of the substrate.

[0020] Figure 3 A circuit diagram of a MEMS device according to an embodiment of this application is shown.

[0021] Figure 4 A flowchart illustrating a method for fabricating a MEMS device according to an embodiment of this application is shown. Detailed Implementation

[0022] The invention will now be described more fully with reference to the accompanying drawings, which illustrate embodiments of the invention. However, the invention can be embodied 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 the invention 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.

[0023] 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 invention, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0024] 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.

[0025] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. 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 “comprise” and / or “comprising,” 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.

[0026] Embodiments of the invention are described herein with reference to cross-sectional views that serve as schematic diagrams of ideal embodiments (and intermediate structures). Thus, variations in the shape shown can be anticipated due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the invention should not be limited to the specific shapes of the regions shown herein, but include shape deviations due to, for example, manufacturing processes. For example, implantation regions shown as rectangular typically have rounded or curved features at their edges and / or implantation concentration gradients, rather than a binary change from implantation regions to non-implantation regions. Similarly, the buried regions formed by implantation can result in some implantation in the region between the buried region and the surface traversed during implantation. Therefore, the regions shown in the figures are substantially schematic, and their shapes are not intended to show the actual shapes of the regions of the device and are not intended to limit the scope of the invention.

[0027] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms as defined in commonly used dictionaries shall be construed as having the meaning consistent with their meaning in the relevant field and / or the context of this specification, and shall not be interpreted in an ideal or overly formal sense, unless expressly defined herein.

[0028] To fully understand this invention, detailed steps and structures will be set forth in the following description to illustrate the technical solution proposed by this invention. Preferred embodiments of the invention are described in detail below; however, in addition to these detailed descriptions, the invention may have other embodiments.

[0029] like Figure 1 As shown, the MEMS sensor 100 according to an embodiment of this application includes a first substrate 101. The surface of the first substrate has trenches 103 and a dielectric layer 104 that fills the trenches and covers the first substrate 101. A first electrode layer 105 is disposed on the dielectric layer 104, and a functional layer 106 is disposed on the first electrode layer 105. A portion of the functional layer 106 is suspended above the first electrode layer 105. The MEMS sensor 100 also includes a second substrate 102, in which a groove is formed. The side of the first substrate 101 where the functional layer 106 is formed is combined with the side of the second substrate 102 where the groove is formed.

[0030] This application increases the distance between the first electrode layer and the first substrate by forming trenches in the first substrate, thereby effectively reducing the ground capacitance of the MEMS device and improving the resolution of the MEMS device. Moreover, the structure is simple and the manufacturing cost is low without increasing the device area or adjusting the dielectric constant of the dielectric layer.

[0031] In one example, the materials of the first substrate 101 and the second substrate 102 can be silicon, germanium, silicon carbide, gallium arsenide, gallium phosphide, indium phosphide, or indium antimonide, etc., or silicon-on-insulator (SOI) or germanium-on-insulator (GOI), other materials such as GaAs, GaAsP, AlInAs, AlGaAs, GaInAs, GaInP, or GaInAsP, etc., or combinations of the above materials. The first substrate 101 may include a doped epitaxial layer, a gradient semiconductor layer, and a semiconductor layer located on top of other semiconductor layers of different types (e.g., a silicon layer on a germanium-silicon layer). An active region and an active region may be disposed in the first substrate 101.

[0032] An isolation region (not shown) is used to isolate the active region. Additionally, a certain number of dopant ions may be implanted into the first substrate 101 according to design requirements. In some embodiments, the first substrate 101 may also include various transistors and other suitable components.

[0033] For example, the first electrode layer 105 comprises polycrystalline silicon or other materials that can be used as capacitor electrodes. Optionally, the first electrode layer may also comprise polycrystalline silicon with dopants. The first electrode layer 105 can typically be used as part of a capacitor electrode in a direction perpendicular to the surface of the first substrate 101. For example, if a third electrode layer is formed in the functional layer, a capacitor is formed between the first electrode layer 105 and the third electrode layer.

[0034] In some embodiments, an interface material layer is further disposed between the first electrode layer 105 and the dielectric layer 104. The interface material layer may include one of silicon oxide, silicon nitride, and silicon oxynitride; in this embodiment, it is silicon oxide, for example. The first electrode layer 105 may include a portion serving as a trace for a MEMS device and a portion serving as a vertically oriented capacitor electrode located on the surface of the first substrate.

[0035] For example, there are multiple trenches, which are spaced apart in the first substrate. The multiple trenches are opposite to at least a portion of the first electrode layer 105, and the trenches 103 are at least partially opposite to the functional layer 103. By forming trenches in the first substrate, this application increases the distance between the first electrode layer and the first substrate, thereby effectively reducing the ground capacitance of the MEMS device and improving the resolution of the MEMS device.

[0036] like Figure 1 As shown, multiple trenches 103 are spaced apart within the first substrate 101, with the trenches 103 opposite to the first electrode layer 105. The first electrode layer 105 is located above the trenches 103, and a partial functional layer 106 is located above the first electrode layer 105. The distance between the first electrode layer 105 and the first substrate 101 is D1, and the distance between the first electrode layer 105 and the bottom of the trenches 103 is D2.

[0037] For example, the projection of the multiple trenches onto the plane of the substrate surface is a grid or a plurality of spaced stripes, or other suitable shape.

[0038] like Figure 2 As shown, in one example, a plurality of strip-shaped trenches 103 are spaced apart within the first substrate 101, and their projection onto the plane containing the surface of the first substrate 101 appears as a grid, and as shown... Figure 2 At least a portion of the plurality of trenches 103 and at least a portion of the first electrode layer 105 are opposite each other, such that the distance between the first electrode layer 105 and the first substrate 101 increases at the trenches 103, and the plurality of trenches 103 correspond at least partially to the functional layer 106.

[0039] In other embodiments, there is one trench, which is opposite to at least a portion of the first electrode layer 105, and the trench 103 is at least partially opposite to the functional layer 106. For example, the trench 103 may correspond to the area of ​​the entire functional layer 106 surrounded by the second substrate, or the trench may correspond to the portion of the entire functional layer 106 that actually performs the function of the MEMS structure. The trench being opposite to at least a portion of the first electrode layer increases the distance between the first electrode layer and the first substrate at the trench 103, thereby effectively reducing the ground capacitance of the MEMS device and improving the resolution of the MEMS device.

[0040] like Figure 1 As shown, the dielectric layer 104 includes a first sub-dielectric layer 104a filling the trenches 103 and a second sub-dielectric layer 104b covering the surface of the first substrate 101 and the first sub-dielectric layer 104a. In embodiments of this application, when there are multiple trenches 103, the width of each trench 103 is less than or equal to half the thickness of the second sub-dielectric layer 104b. When multiple trenches are spaced apart along a first direction, the width refers to the dimension in the first direction, as shown in the reference. Figure 1 Multiple trenches are arranged at intervals along the D direction, and the width of trench 103 refers to... Figure 1 The dimension in the D direction. By making the width of each trench 103 less than or equal to half the thickness of the second sub-dielectric layer 104b, the surface flatness of the first sub-dielectric layer 104a filling the trench 103 is better.

[0041] A functional layer 106 is disposed on the first electrode layer 105, and a portion of the functional layer 106 is suspended above the first electrode layer 105. The functional layer 120 is, for example, a polycrystalline silicon material layer used to form the capacitor structure of a MEMS inertial sensor. The polycrystalline silicon material layer includes polycrystalline silicon with dopants. Specifically, the polycrystalline silicon material layer may include a seed polycrystalline silicon layer (not shown) and a polycrystalline silicon conductive layer sequentially stacked on the first wafer 100. In one embodiment, the thickness of the functional layer 120 is about 20 μm to 30 μm.

[0042] In this configuration, a portion of the functional layer 106 is suspended above the first electrode layer 105, while another portion of the functional layer 106 is connected to a portion of the first electrode layer 105, thereby forming a cavity between the first electrode layer 105 and the functional layer 106. For example, as shown... Figure 1 As shown, the MEMS sensor 100 also includes a second substrate 102, in which a groove is formed.

[0043] A second electrode layer 107 is disposed in the groove of the second substrate 102. The second electrode layer 107 is opposite to the first electrode layer 105, and the functional layer 106 is located between the second electrode layer 107 and the first electrode layer 105.

[0044] For example, the material including the polycrystalline silicon second electrode layer includes polycrystalline silicon, or other materials that can be used as capacitor electrodes. In this embodiment, the second electrode layer may include polycrystalline silicon with dopants.

[0045] Continue to refer to, for example Figure 1 The first substrate 101 with the functional layer 106 is bonded to the second substrate 102 with the groove. A bonding structure is provided between the functional layer 106 on the first substrate 101 and the second substrate 102. The first substrate 101 and the second substrate 102 are bonded together by the bonding structure.

[0046] The functional layer 106 is suspended on the first substrate 101, thereby forming a cavity between the upper surface of the first substrate 101 and the functional layer 106. Depending on the application, the upper surface of the functional layer 106 includes a central region I and a bonding region II located around the central region I. The bonding region II is used for subsequent bonding with the second substrate 102, and the bonding region II can be annular. The central region I is located inside the bonding region II and can be used to set the functional components of a MEMS sensor. In this embodiment, the central region I on the upper surface of the functional layer 106 can be used to set the capacitive structure of an inertial sensor.

[0047] Figure 3The diagram illustrates a circuit diagram of a MEMS device according to an embodiment of this application, where capacitor CPG is the MEMS device's capacitance to ground. In the circuit structure of a MEMS device, the size of the capacitance to ground CPG directly affects the device's bandwidth and noise density.

[0048] Combination Figure 1 and Figure 3 The capacitance to ground of the MEMS device described in this application embodiment is calculated using the following formula:

[0049] C=εA / d

[0050] C represents the capacitance to ground of the first electrode layer 105, ε represents the dielectric constant of the dielectric layer 104, d represents the distance between the first electrode layer 105 and the first substrate 101, and A represents the area of ​​the first electrode layer 105 and the first substrate 101 facing each other. At the trench 103, the distance between the first electrode layer 105 and the first substrate 101 increases, and the increase is equal to the depth of the trench 103. This reduces the capacitance to ground of the first electrode layer 105, thereby effectively reducing the capacitance to ground of the MEMS device without increasing the device area or adjusting the dielectric constant of the dielectric layer.

[0051] In one example, such as Figure 1 and Figure 3 As shown, the polycrystalline silicon material layer disposed in the intermediate region I of the first electrode layer 105 and the functional layer 106 constitutes... Figure 3 The capacitor CP1 is composed of a polycrystalline silicon material layer disposed in the middle region I of the functional layer 106 of the second electrode layer 107. Figure 3 When the functional layer moves, the voltage across capacitors CP1 and CP2 changes. The MEMS device determines the movement of the functional layer 106 based on the voltage change across capacitors CP1 and CP2.

[0052] The MEMS device of this application embodiment has trenches and filled trenches on the surface of a first substrate, and a dielectric layer covering the first substrate. A first electrode layer is disposed on the dielectric layer, and a functional layer is disposed on the first electrode layer. Part of the functional layer is suspended above the first electrode layer. It also has a second substrate, in which a groove is formed. The side of the first substrate where the functional layer is formed is combined with the side of the second substrate where the groove is formed. By forming trenches in the first substrate, this application increases the distance between the first electrode layer and the first substrate, thereby effectively reducing the ground capacitance of the MEMS device and improving the resolution of the MEMS device. Moreover, the MEMS device of this application has a simple structure and low manufacturing cost without increasing the device area or adjusting the dielectric constant of the dielectric layer.

[0053] In another embodiment of this application, such as Figure 4As shown, this application also provides a method for fabricating a MEMS device, including the following steps S401 to S402.

[0054] First, step S401 is performed to provide a first substrate. Then, step S402 is performed to form a trench in the first substrate, the trench extending from the surface of the first substrate into the first substrate.

[0055] For example, forming a trench in a first substrate includes: when the depth of the predetermined trench is less than a preset threshold, performing dry etching and / or wet etching on the first substrate to form the trench; and when the depth of the predetermined trench is greater than or equal to the preset threshold, performing deep silicon etching on the first substrate to form the trench.

[0056] In one example, based on the required trench depth, the required trench depth is compared with a preset threshold. When the depth of the trench to be formed is less than the preset threshold, dry etching and / or wet etching are performed on the first substrate, which is less costly. When the depth of the trench to be formed is greater than or equal to the preset threshold, dry etching and / or possibly deep silicon etching are used on the first substrate to make the trench aspect ratio meet the requirements of MEMS devices and improve the smoothness of the trench sidewalls, thereby improving the reliability of MEMS devices.

[0057] like Figure 1 As shown, forming trenches may include etching multiple trenches 103 at intervals within the first substrate 101, and then, through subsequent steps, positioning the multiple trenches 103 relative to the position of the first electrode layer 105, with the functional layer 106 partially located directly above the first electrode layer 105.

[0058] like Figure 2 As shown, forming the trench may further include providing a plurality of strip trenches 103 spaced apart within the first substrate 101, the projection of which onto the plane containing the first surface of the first substrate 101 is displayed as a grid, and, after subsequent steps, as shown... Figure 2 At least a portion of the plurality of trenches 103 are opposite to at least a portion of the first electrode layer 105, and the plurality of trenches 103 are at least partially opposite to the functional layer.

[0059] Forming a trench may also include forming a trench that is opposite to at least a portion of the first electrode layer and that corresponds at least partially to the functional layer.

[0060] Next, step S403 is performed to form a dielectric layer to cover the surface of the first substrate and fill the trench.

[0061] In one example, forming the dielectric layer includes depositing an oxide layer on the surface of a first substrate. For example... Figure 1As shown, in step S403, the dielectric layer 104 includes a first sub-dielectric layer 104a filling the trench 103 and a second sub-dielectric layer 104b covering the surface of the first substrate 101 and the first sub-dielectric layer 104a. In the embodiments of this application, when multiple trenches are spaced apart along a first direction, the width of each trench 103 is less than or equal to half the thickness of the second sub-dielectric layer 104b, resulting in better surface flatness of the first sub-dielectric layer 104a filling the trench 103 in step S403.

[0062] Next, step S404 is performed to form a first electrode layer on the dielectric layer; a functional layer is formed above the first electrode layer, with a portion of the functional layer suspended above the first electrode layer. In one example, forming the first electrode layer on the dielectric layer includes forming a patterned polysilicon electrode layer on the dielectric layer. Then, a functional layer is formed above the first electrode layer. Exemplarily, forming the functional layer above the first electrode layer includes: forming a sacrificial layer above the first electrode layer, forming a functional material layer on the sacrificial layer; removing a portion of the functional material layer to form the functional layer, and removing a portion of the sacrificial layer to form a cavity on the first substrate, such that a portion of the functional layer is suspended above the first electrode layer. In one example, a sacrificial layer is first deposited and formed above the first electrode layer, then a functional material layer is deposited and formed on the sacrificial layer, and then the functional material layer is etched to form a release hole in the functional material layer to remove the sacrificial layer and form a cavity, such that a portion of the functional layer is suspended above the first electrode layer. Figure 1 As shown.

[0063] Then, step S405 is executed to provide a second substrate, in which a groove is formed. In one example, the second substrate is formed by dry etching and / or wet etching. In step S406, the groove is positioned opposite the first electrode layer and the functional layer. Figure 1 As shown.

[0064] Then, step S406 is executed to combine the side of the first substrate where the functional layer is formed with the side of the second substrate where the groove is formed. In one example, such as... Figure 1 As shown, a bonding structure is provided between the functional layer 106 on the first substrate 101 and the second substrate 102, and the first substrate 101 and the second substrate 102 are combined by the bonding structure. In the combined MEMS device, the trench in the first substrate is at least opposite to a portion of the first electrode layer, a portion of the functional layer and a portion of the second electrode layer.

[0065] 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.

[0066] For example, taking a MEMS inertial sensor as an example, the electronic device provided in this application may include the following parts: a MEMS inertial sensor, a driving circuit, a control system, and a housing. The MEMS inertial sensor is the core component of the electronic device; it is used to detect and measure acceleration, tilt, impact, vibration, rotation, and multi-degree-of-freedom motion. The driving circuit provides voltage or current signals to the MEMS inertial sensor and needs to be compatible with the sensor's operating mode and driving method. The control system provides control signals and data processing for the electronic device and needs to be compatible with the MEMS inertial sensor's control interface and application functions. The housing provides protection and fixation for the electronic device and needs to be compatible with the size and shape of the MEMS inertial sensor.

[0067] The electronic device provided in this application can be any electronic product or device with similar functions or performance, such as unmanned vehicles, drones, robots, mobile phones, tablets, game consoles, cameras, VR glasses, etc., or any intermediate product including the aforementioned MEMS inertial sensors. Unmanned vehicles perceive the external environment and acquire vehicle position, attitude, and obstacle information through onboard sensors including the aforementioned MEMS inertial sensors, thereby controlling vehicle speed, steering, and start-stop. When an unmanned vehicle travels under a tall building and its GPS is blocked, the inertial navigation system onboard with the aforementioned MEMS inertial sensors can meet the vehicle's autonomous driving needs for a short period. Drones play an increasingly important role in both military and civilian fields, and attitude measurement and control systems play a crucial role in achieving drone positioning and addressing positioning issues. These systems mainly consist of a GPS antenna, a GPS receiver board, a strapdown magnetic sensor, an inertial measurement unit, an altitude and airspeed sensor, and a conditioning unit. The accuracy of the sensors directly determines the accuracy of the drone's attitude; the data collected by the sensors is used to calculate the drone's position and attitude information through navigation algorithms. Unmanned aerial vehicles (UAVs) employ a combination of MEMS inertial navigation systems and GPS for navigation. The aforementioned MEMS inertial sensors improve navigation accuracy and attitude control precision, thereby enhancing the reliability and flight performance of the UAVs. Robots are automated devices capable of autonomously operating in fixed or time-varying environments. In recent years, they have been widely used in service industries, home environments, and industrial sectors. Wheeled robots are similar to unmanned vehicles in their applications, both using sensors such as visual cameras, MEMS inertial sensors, LiDAR, and odometers to collect data for navigation.In the navigation of wheeled robots employing inertial sensors and odometry, MEMS inertial sensors provide precise attitude angles. However, wheel slippage and other factors can affect inertial navigation and odometry. Currently, navigation often combines visual odometry with MEMS inertial sensors, using extended Kalman filtering algorithms for data fusion to improve system accuracy. VR devices utilize Virtual Reality (VR) technology to place users in a fully immersive virtual environment, providing a sense of presence. AR devices utilize Augmented Reality (AR) technology... VR / AR (Real-Time Analysis) technology overlays virtual objects onto real-world scenes, allowing users to experience a blend of virtual and real worlds. VR / AR devices are typically wearable glasses or helmets, but can also be non-wearable devices like smartphones or tablets. They utilize screens, lenses, sensors, cameras, projectors, and optical systems to present and interact with virtual environments, as well as generate and locate virtual objects. VR / AR devices incorporating the aforementioned MEMS inertial sensors can achieve precise positioning and human posture perception, adjusting image presentation based on these perceptions. Applications of such VR / AR devices include education, entertainment, healthcare, gaming, and the metaverse. In summary, the electronic device provided in this application, due to the use of the aforementioned MEMS inertial sensors, exhibits superior performance.

[0068] It should be noted that the above embodiments are illustrative of this application and not limiting of it, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. This application can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several vehicle systems, several of these vehicle systems may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

[0069] The above are merely specific embodiments or descriptions of specific embodiments of this application. The scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. The scope of protection of this application shall be determined by the scope of the claims.

Claims

1. A MEMS device, characterized in that, include: A first substrate has trenches on its surface and a dielectric layer filling the trenches and covering the first substrate. A first electrode layer, which is a capacitor electrode layer, is disposed on the dielectric layer. A functional layer is disposed on the first electrode layer. A cavity exists between the first electrode layer and a portion of the functional layer so that a portion of the functional layer is suspended above the first electrode layer. The dielectric layer filling the trenches is used to increase the distance between the first electrode layer and the first substrate to reduce the capacitance to ground. A second substrate has a groove formed therein, and the side of the first substrate in which the functional layer is formed is combined with the side of the second substrate in which the groove is formed.

2. The MEMS device according to claim 1, characterized in that, The trenches are multiple in number and are spaced apart within the first substrate. The trenches are opposite to at least a portion of the first electrode layer and at least partially correspond to the functional layer.

3. The MEMS device according to claim 2, characterized in that, The projection of the plurality of trenches onto the plane of the substrate surface is a grid or a plurality of spaced stripes.

4. The MEMS device according to claim 1, characterized in that, The number of the trenches is one, one trench is opposite to at least a portion of the first electrode layer, and the trench is at least partially opposite to the functional layer.

5. The MEMS device according to claim 1, characterized in that, When there are multiple trenches, the dielectric layer includes a first sub-dielectric layer that fills the trenches and a second sub-dielectric layer that covers the surface of the first substrate and the first sub-dielectric layer, wherein the width of each trench is less than or equal to half the thickness of the second sub-dielectric layer.

6. The MEMS device according to claim 1, characterized in that, The groove of the second substrate has a second electrode layer disposed on the surface facing the first substrate.

7. The MEMS device according to claim 6, characterized in that, The material of the first electrode layer includes polycrystalline silicon, and the material of the second electrode layer includes polycrystalline silicon.

8. A method for fabricating a MEMS device, characterized in that, The method includes: Provide a first substrate; A trench is formed within the first substrate, the trench extending from the surface of the first substrate into the first substrate; A dielectric layer is formed to cover the surface of the first substrate and fill the trench; A first electrode layer is formed on the dielectric layer, the first electrode layer being a capacitor electrode layer; a functional layer is formed above the first electrode layer, and a cavity is provided between the first electrode layer and a portion of the functional layer, so that a portion of the functional layer is suspended above the first electrode layer; wherein, the dielectric layer filling the trench is used to increase the distance between the first electrode layer and the first substrate to reduce the capacitance to ground. A second substrate is provided, and a groove is formed in the second substrate; The side of the first substrate where the functional layer is formed is combined with the side of the second substrate where the groove is formed.

9. The preparation method according to claim 8, characterized in that, Forming a functional layer above the first electrode layer includes: A sacrificial layer is formed above the first electrode layer, and a functional material layer is formed on the sacrificial layer; A portion of the functional material layer is removed to form a functional layer, and a portion of the sacrificial layer is removed to form a cavity on the first substrate, such that a portion of the functional layer is suspended above the first electrode layer.

10. The preparation method according to claim 8, characterized in that, Forming a trench in the first substrate includes: when the depth of the trench to be formed is less than a preset threshold, performing dry etching and / or wet etching on the first substrate to form the trench; When the depth of the predetermined trench is greater than or equal to the preset threshold, deep silicon etching is performed on the first substrate to form the trench.

11. An electronic device, characterized in that, Includes the MEMS device as described in any one of claims 1-7.

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