An accelerometer

Abstract

The embodiment of the application discloses an accelerometer. Wherein, the accelerometer comprises: a substrate, the substrate has a detection layer on the surface; an anchor assembly is arranged on the substrate; the anchor assembly has a plurality of anchor points symmetrically distributed along the center and in the XY plane; a mass is connected with the anchor assembly through a connecting arm and is suspended above the substrate; the mass is configured to form a detection capacitor with the detection layer and generate Z-axis displacement under the action of Z-axis acceleration; wherein, the anchor assembly is configured to inhibit the transmission of anchor point shear force in the X direction and / or the Y direction at the anchor point to the mass; the XY plane is parallel to the surface of the substrate, and the Z axis is perpendicular to the XY plane. Through the embodiment of the application, the technical problem of how to actively inhibit or compensate the anchor point shear force is solved.

Description

Technical Field

[0001] This application relates to the field of microelectromechanical technology, and in particular to an accelerometer. Background Technology

[0002] In modern inertial measurement, structural health monitoring, and precision motion control, the Z-axis accelerometer is a core sensor, and its measurement accuracy directly determines system performance. However, traditional Z-axis accelerometers commonly face a critical problem in practical applications: interference from shear stress at the structural anchor points. This interference, which may arise from front-end manufacturing, back-end packaging, and PCB assembly stress, can cause relative displacement between the substrate and structural layers of the Z-axis accelerometer. The structural layer will tilt due to the deformation of the anchor points, thus introducing measurement errors. Especially in low-frequency vibration or quasi-static acceleration measurement scenarios, such errors can significantly reduce the sensor's signal-to-noise ratio and long-term stability.

[0003] Existing technologies attempt to alleviate these problems by optimizing manufacturing processes and compensating for back-end circuitry. However, optimizing manufacturing processes is time-consuming and labor-intensive, requiring extensive process debugging to determine optimal process conditions. Back-end circuitry compensation, on the other hand, significantly increases the complexity of circuit design and also increases circuit power consumption. Summary of the Invention

[0004] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes an accelerometer to solve the technical problem of how to actively suppress or compensate for anchor point shear forces.

[0005] This application provides an accelerometer, including: Substrate, wherein a detection layer is present on the surface of the substrate; An anchoring assembly is disposed on the substrate; the anchoring assembly has a plurality of anchor points symmetrically distributed along its center in the XY plane; A mass block is connected to the anchoring assembly via a connecting arm and suspended above the substrate; the mass block is configured to form a detection capacitance with the detection layer and generate Z-axis displacement under Z-axis acceleration. The anchoring component is configured to suppress the transmission of anchor shear force in the X and / or Y directions at the anchor point to the mass block; the XY plane is parallel to the substrate surface, and the Z axis is perpendicular to the XY plane.

[0006] In at least some embodiments of this application, The anchoring component includes: A frame is circumferentially arranged along the plurality of anchor points and connected to the connecting arm; An elastic component connects the anchor point and the frame, and both the elastic component and the anchor point are symmetrically distributed along the center of the frame in the XY plane; the elastic component is configured to counteract the anchor point shear force in the X direction and / or Y direction, so that the frame remains parallel to the XY plane.

[0007] In at least some embodiments of this application, The elastic component includes a first elastic element, a second elastic element, a third elastic element, and a fourth elastic element; The first elastic element extends circumferentially along each anchor point and connects the anchor point and the second elastic element; The second elastic element is arranged between adjacent anchor points and converges at the center of the anchoring assembly; The third elastic element connects the corner of the anchor point near the center of the anchoring assembly to the intersection of the second elastic element; The fourth elastic element is arranged around the periphery of the plurality of anchor points and connects the second elastic element and the frame.

[0008] In at least some embodiments of this application, The first elastic element includes a plurality of elastic beam structures; each elastic beam structure includes an L-shaped first elastic beam and a second elastic beam that are interconnected; the first elastic beam is arranged along the X or Y direction, and the second elastic beam is arranged perpendicular to the first elastic beam; the first elastic beam and the second elastic beam are respectively located on adjacent sides of the same anchor point; one end of the first elastic beam is connected to the corresponding anchor point, and one end of the second elastic beam is connected to the adjacent second elastic element.

[0009] In at least some embodiments of this application, The second elastic element includes a plurality of first elastic straight beams, which are arranged along the X or Y direction; the plurality of first elastic straight beams intersect and connect at the center of the anchoring assembly; the connection points of the first elastic elements on both sides of the first elastic straight beams and the first elastic straight beams are in the same X or Y direction.

[0010] In at least some embodiments of this application, The fourth elastic element includes a plurality of second elastic straight beams connected end to end, the second elastic straight beams being arranged along the X or Y direction; each second elastic straight beam having a gap between itself and the adjacent frame and being connected to the frame at the end-to-end connection; each second elastic straight beam being connected to the adjacent first elastic straight beam and being perpendicular to each other.

[0011] In at least some embodiments of this application, The elastic component is provided with at least one stress relief hole.

[0012] In at least some embodiments of this application, A first stress relief hole is provided at the intersection of the second elastic elements; and / or, a plurality of second stress relief holes are provided on the second elastic elements, the plurality of second stress relief holes being symmetrically distributed about the center of the anchoring assembly; each second stress relief hole is arranged at a connection point between the first elastic element and the second elastic element that is close to it.

[0013] In at least some embodiments of this application, The connecting arm has at least two arms, which are arranged along the Y direction on both sides of the anchoring component and symmetrically distributed about the center of the anchoring component; the connection between the connecting arm and the mass block and the connection between the connecting arm and the anchoring component are provided with transition chamfers.

[0014] In at least some embodiments of this application, The connecting arm is provided with symmetrical auxiliary beams that extend along the Y direction on both sides; the auxiliary beams are connected to the connection between the connecting arm and the anchoring assembly.

[0015] In at least some embodiments of this application, The mass block includes a first mass block and a second mass block located on both sides of the anchoring component and arranged along the X direction; the second mass block has an opening near the anchoring component.

[0016] The above-described one or more embodiments of this application have at least one or more of the following beneficial effects: In implementing the technical solution of this application, the anchoring components and the symmetrically distributed multi-anchor point design can mutually cancel out the shear forces introduced by internal factors or external interference, and avoid the transmission of anchor point shear deformation to the mass block, thereby fundamentally reducing the interference of anchor point shear force on Z-axis measurement accuracy and improving the reliability and accuracy of the sensor under complex working conditions. In addition, the accelerometer of this application is compatible with the standard MEMS processing technology of the original traditional structure, without the need for additional process development costs, which greatly reduces production costs. At the same time, it has a higher tolerance for back-end circuits, reducing the complexity of circuit design.

[0017] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0018] The disclosure of this application will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this application. Furthermore, similar numbers in the drawings are used to denote similar components, wherein: Figure 1 A structural diagram of a Z-axis accelerometer with a single anchor point structure; Figure 2 A three-dimensional cross-sectional view of a Z-axis accelerometer with a single anchor point structure along the XZ plane; Figure 3 A side view of the Z-axis accelerometer with a single anchor point structure along the XZ plane. Figure 4 Displacement contour plot of a Z-axis accelerometer with a single anchor point structure under anchor point shear force in the x-direction; Figure 5 A top view of an accelerometer that can suppress the influence of anchor point shear force, provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of an anchoring component for an accelerometer provided in an embodiment of this application; Figure 7 A schematic diagram of another anchoring component for an accelerometer provided in an embodiment of this application; Figure 8 The displacement contour plot of the accelerometer under the action of anchor shear force in the X direction is provided in the embodiment of this application; Figure 9 The displacement contour map of the accelerometer anchoring assembly provided in this application embodiment under the action of anchor point shear force in the X direction; Figure 10 The displacement contour plot of the accelerometer under the action of anchor shear force in the Y direction is provided in the embodiment of this application; Figure 11 The displacement contour map of the accelerometer anchoring assembly provided in this application embodiment under the action of anchor point shear force in the Y direction. Detailed Implementation

[0019] Some embodiments of this application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of this application and are not intended to limit the scope of protection of this application.

[0020] like Figure 1 The diagram shows a schematic of a single-anchor-point Z-axis accelerometer, with the Z-axis arrow pointing upwards. This single-anchor-point Z-axis accelerometer includes a substrate 1, a sensitive structure layer 3, and a detection layer on the substrate 1, all distributed along the Z-direction. The sensitive structure layer 3 consists of a single anchor point 301, connecting arms 370a and 370b, and a mass block. The mass block includes a first mass block 380a and a second mass block 380b, located on either side of the single anchor point 301 along the X-direction. A large opening 380c is formed in the second mass block 380b, effectively hollowing out its mass to improve the detection sensitivity of the Z-axis. Both connecting arms 370a and 370b are elastically torsion-resistant beams.

[0021] Figure 2 for Figure 1 A three-dimensional cross-sectional view of the Z-axis accelerometer with a single anchor point structure along the XZ plane. (See image below.) Figure 2 As shown, substrate 1 serves as the supporting base for the entire device structure and is typically made of single-crystal silicon with a thickness of approximately 300-500 μm. Support pillars 2, extending along the Z-direction and with a thickness of 1-5 μm, are distributed on the upper surface of substrate 1. These support pillars are only connected to anchor points 301 of the sensitive structure layer 3. The first mass block 380a and the second mass block 380b of the sensitive structure layer are connected to anchor points 301 via connecting arms 370a and 370b. Therefore, the first mass block 380a and the second mass block 380b are suspended on substrate 1, with space for movement both above and below, allowing them to move in the Z-direction.

[0022] Figure 3 for Figure 1 The single-anchor-point Z-axis accelerometer in the image is shown in the cross-sectional side view along the XZ plane. Figure 3 As shown, a metal layer is deposited on the surface of substrate 1 as a detection layer. The electrode regions of the detection layer are located on the left and right sides of substrate 1, namely the first detection electrode 401a and the second detection electrode 401b, which are divided into P-ends and N-ends. The first detection electrode 401a and the second detection electrode 401b are located directly below the outer regions of the first mass block 380a and the second mass block 380b, respectively. The first mass block 380a and the first detection electrode 401a constitute the first detection capacitor C1, and the second mass block 380b and the second detection electrode 401b constitute the second detection capacitor C2. Under the action of Z-axis acceleration, the first mass block 380a and the second mass block 380b, due to their mass asymmetry, will generate a non-zero torque, causing the first mass block 380a and the second mass block 380b to perform a seesaw motion around the connecting arm 370a and the connecting arm 370b. When the first mass block 380a moves upward, the gap between the first mass block 380a and the first detection electrode 401a increases, and the first detection capacitor C1 decreases. Correspondingly, the second mass block 380b will descend, reducing the gap between the second mass block 380b and the second detection electrode 401b, and increasing the second detection capacitor C2. The first detection capacitor C1 and the second detection capacitor C2 form a differential detection. Assuming that the initial values ​​of C1 and C2 are both C0, during the movement of the mass block, the first detection capacitor C1 = C0 - C, the second detection capacitor C2 = C0 + C, the total capacitor output will be C2 - C1 = 2 C. Then, the capacitor output is converted into a voltage output by the CV circuit at the back end, and the magnitude of the input acceleration can be read. Ideally, in the absence of acceleration input, the first mass block 380a and the second mass block 380b should remain in a horizontal position, and the total capacitor output will be C2-C1=0. However, in reality, there is anchor point shear stress inside the accelerometer due to various factors such as front-end manufacturing, back-end packaging, and PCB assembly stress. The shear deformation of the anchor point will cause the mass block to be in a non-ideal tilted state even without acceleration input.

[0023] like Figure 4 The diagram shows the displacement contour of a single-anchor-point Z-axis accelerometer under X-direction anchor shear force. A Z-direction displacement of 1 nm is assigned to the left side of anchor point 301 in sensitive structure layer 3, and a Z-direction displacement of -1 nm is assigned to the right side. It can be seen that the single-anchor-point Z-axis accelerometer cannot resist anchor shear deformation. The first mass block 380a and the second mass block 380b exhibit significant Z-direction displacement following the anchor point deformation, with the outer displacement exceeding 25 nm. Consequently, the accelerometer will produce a large, non-ideal zero-bias output.

[0024] Based on the above issues, such as Figure 5 The embodiment shown in this application provides a Z-axis accelerometer capable of suppressing the influence of anchor point shear force. This accelerometer references... Figures 1-3 It also includes a substrate 1 distributed along the Z direction, a sensitive structure layer 3, and a detection layer on the substrate 1; Reference Figure 5 The sensitive structure layer 3 includes an anchoring component 301 and a mass block. The anchoring component 301 has multiple anchor points symmetrically distributed along its center in the XY plane. The mass block is connected to the anchoring component via connecting arms 370a and 370b and is suspended above the substrate. The mass block is configured to form a detection capacitance with the detection layer and generate Z-axis displacement under Z-axis acceleration. The anchoring component 301 is configured to suppress the transmission of anchor shear force in the X and / or Y directions to the mass block. The XY plane is parallel to the substrate surface, and the Z-axis is perpendicular to the XY plane. The anchoring component 301 and the symmetrically distributed multiple anchor points can mutually cancel out the shear force introduced by internal factors or external interference, preventing the transmission of anchor shear deformation to the mass block. This fundamentally reduces the interference of anchor shear force on Z-axis measurement accuracy and improves the reliability and accuracy of the sensor under complex working conditions.

[0025] Specifically, each anchor point is fixedly supported by a support column 2 extending along the Z direction, and the entire sensitive structure layer 3 is fixedly connected to the substrate 1 via the anchor points and the corresponding support columns 2. The mass block is connected to the anchoring assembly 301 via a connecting arm; the specific placement and arrangement of the mass block and connecting arm can be found in [reference needed]. Figures 1-3Specifically, the mass block includes a first mass block 380a and a second mass block 380b located on both sides of the anchoring assembly and arranged along the X direction. The second mass block 380b has an opening 380c near the anchoring assembly 301, reducing its mass compared to the first mass block 380a, thereby improving the detection sensitivity of the Z-axis. In this embodiment, the anchoring assembly 301 abandons the single-anchor-point design and the double-anchor-point design, adopting a four-anchor-point design. This is because single-anchor-point and double-anchor-point designs cannot suppress, or can only suppress, the transmission of anchor point shear deformation in a single direction to the mass block, while the four-anchor-point design can suppress the transmission of anchor point shear deformation in multiple directions to the mass block, thereby reducing the interference of anchor point shear force on the Z-axis measurement accuracy.

[0026] Among them, the connecting arms 370a and 370b of the sensitive structural layer 3 also have elastically torsionable straight beams, and are arranged on both sides of the anchoring assembly along the Y direction; and with Figures 1-3 The difference in this embodiment is that a large-radius transition chamfer is provided at the root of the straight beam, i.e., at the connection with the mass block and anchoring assembly 301, which can increase the structural connection strength and prevent breakage during torsion. Furthermore, two auxiliary beams of the same width are provided on both sides of the connecting arm 370a and the connecting arm 370b. The auxiliary beams extend along the Y direction, i.e., they are straight beams, to ensure etching uniformity.

[0027] In one specific implementation method Figure 6 This is a schematic diagram of an anchoring structure for a Z-axis accelerometer provided in an embodiment of this application. Figure 6 As shown, the anchoring assembly 301 includes: a frame 360, circumferentially arranged along a plurality of anchor points and connected to a connecting arm; an elastic component, connecting the anchor points and the frame 360, wherein the elastic component and the anchor points are symmetrically distributed in the XY plane along the center of the frame 360; the elastic component is configured to counteract the anchor point shear force in the X direction and / or Y direction, so that the frame 360 ​​remains parallel to the XY plane. Specifically, in this embodiment, the anchoring assembly 301 includes four fixed anchor points, namely anchor point 302, anchor point 304, anchor point 306 and anchor point 308; as Figure 6The horizontal and vertical dashed lines are used to divide the quadrants, with the four fixed anchor points distributed in the four quadrants and symmetrical about the horizontal and vertical quadrant boundaries. The elastic component includes a first elastic element, a second elastic element, a third elastic element, and a fourth elastic element. The first elastic element extends circumferentially along each anchor point and connects the anchor point and the second elastic element. The first elastic element can absorb energy from the shear force of the anchor point through deformation and transfer it to the second elastic element. The second elastic element is arranged between adjacent anchor points and converges at the center of the anchoring component. The second elastic element is the main elastic support and stress dispersion structure, connecting other elastic units and absorbing energy. The third elastic element connects a corner of the anchor point near the center of the anchoring component and the intersection with the second elastic element. The third elastic element will transfer the shear deformation of the anchor point to the intersection of the second elastic elements. The fourth elastic element is arranged around the periphery of multiple anchor points and connects the second elastic element and the frame, serving as the outermost elastic support of the entire elastic component.

[0028] Specifically, the first elastic element comprises eight elastic beam structures (see reference). Figure 6 The elastic beam structures 311, 312, 313, 314, 315, 316, 317, and 318 are all L-shaped. Each elastic beam structure includes a first elastic beam and a second elastic beam that are connected to each other. The first elastic beam is arranged along the X or Y direction, and the second elastic beam is arranged perpendicular to the first elastic beam. The first and second elastic beams are located on adjacent sides of the same anchor point. One end of the first elastic beam is connected to the corresponding anchor point, and one end of the second elastic beam is connected to the adjacent second elastic element. Taking the elastic beam structure 311 as an example, the first elastic beam of the elastic beam structure 311 is arranged along the Y direction, and the second elastic beam is arranged along the X direction. The top of the first elastic beam serves as one end of the elastic beam structure 311 and is connected to the anchor point 302. The connection position is approximately 5% to 15% of the side length of the anchor point 302 and close to a corner away from the quadrant center. The end of the second elastic beam serves as the other end of the elastic beam structure 311 and is connected to the nearby second elastic element. The connection position is close to the middle of the arm of the second elastic element in the second and third quadrants, approximately 40% to 60% away from the quadrant center. The L-shaped beam design of the first elastic element can absorb energy through small deformations, avoiding stress concentration at the connection between the beam and the anchor point, which could lead to structural failure. On the other hand, it increases the stiffness of the anchoring assembly 301 in the rotational direction. Finally, the first elastic element transfers the shear deformation at the anchor point to the connection position with the second elastic element, causing the second elastic element to displace along the Z direction.

[0029] The second elastic element consists of four first elastic straight beams (see reference). Figure 6The anchoring assembly 301 comprises four first elastic beams: 322, 324, 326, and 328. First elastic beams 322 and 326 are arranged along the Y-direction, while first elastic beams 324 and 328 are arranged along the X-direction. These four first elastic beams converge at the center of the anchoring assembly 301, forming a cross shape. Each first elastic beam arranged in the Y-direction connects to the elastic beam structures of the first elastic elements on the left and right sides, with the connection points at the same location. Similarly, each first elastic beam arranged in the X-direction connects to the elastic beam structures of the first elastic elements on the upper and lower sides, with the connection points at the same location. For example, the first elastic beam 322, arranged along the Y-direction, connects to the elastic beam structure 312 on the left (second quadrant) and the elastic beam structure 313 on the right (first quadrant), with the connection points at the same location, i.e., in the same X-direction, approximately 40-60% of the length of the first elastic beam 322. The second elastic element includes a plurality of first elastic straight beams, which are arranged along the X or Y direction; the plurality of first elastic straight beams intersect and connect at the center of the anchoring assembly; the connection points of the first elastic elements on both sides of the first elastic straight beams and the first elastic straight beams are in the same X or Y direction.

[0030] The third elastic element consists of four short beams (see reference). Figure 6 The anchoring assembly 301 is composed of short beams 332, 334, 336, and 338. These short beams are arranged at 45°, 135°, 225°, and 315° angles, starting from the positive X-axis. One end of each short beam connects to a corner of the nearest anchor point, and the other end connects to the intersection with the second elastic element. Taking short beam 332 as an example, it is arranged at 135°. The upper left end of short beam 332 (the end furthest from the quadrant center) connects to the lower right corner of the nearest anchor point 302, and the lower right end of short beam (the end closest to the quadrant center) connects to the intersection with the second elastic element. The short beams are relatively short and directly connected to the anchor points, providing sufficient translational and rotational stiffness for the entire anchoring assembly 301. Simultaneously, the third elastic element transmits the shear deformation of each anchor point to the intersection of the second elastic element, causing the second elastic element to tilt.

[0031] The fourth elastic element consists of four second elastic straight beams (reference). Figure 6The system comprises four second elastic beams (342, 344, 346, and 348), whose placement and connection methods differ from those of the second elastic element. Second elastic beam 342 is placed along the X-direction, and second elastic beam 344 is placed along the Y-direction, with its first end connected to the last end of the second elastic beam 342. Second elastic beam 346 is placed along the X-direction, with its first end connected to the last end of the second elastic beam 344. Second elastic beam 348 is placed along the Y-direction, with its first end connected to the last end of the second elastic beam 346, and its last end connected to the first end of the second elastic beam 342. The four second elastic beams are connected end-to-end in a U-shape. The middle portion of each second elastic beam connects to the first elastic beam of the adjacent second elastic element, arranged perpendicularly to each other. Each second elastic beam has a gap between itself and the adjacent frame 360 ​​and connects to the frame 360 ​​at its end-to-end connection, allowing for some deformation space.

[0032] Based on the above implementation, when the direction of the anchor point shear force is along the positive x-axis, the four fixed anchor points (anchor points 302, 304, 306, and 308) deform under the action of the shear force. The left side of the anchor point moves upward along the z-direction, and the right side of the anchor point moves downward along the z-direction, with each anchor point in an inclined state. Elastic beam structures 311 and 318 are connected to the left sides of anchor points 302 and 308 respectively, transmitting the positive z-direction displacement of the anchor points to the first elastic straight beam 328; elastic beam structures 314 and 315 are connected to the right sides of anchor points 304 and 306 respectively, transmitting the negative z-direction displacement of the anchor points to the first elastic straight beam 324. Therefore, the cross structure of the second elastic element can be considered as being acted upon by a torque M3 around the vertical dotted line. On the other hand, short beams 332 and 338 are connected to the right side of anchor point 302 and anchor point 308 respectively, transmitting the negative z-direction displacement of the anchor point to the first elastic straight beam 328; short beams 334 and 336 are connected to the left side of anchor point 304 and anchor point 306 respectively, transmitting the positive z-direction displacement of the anchor point to the first elastic straight beam 324. The cross structure of the second elastic element can be regarded as being subjected to a torque M4 opposite to the direction of torque M3. The final result is that torques M3 and M4 cancel each other out, so that the rigid frame 360 ​​of the anchoring assembly 301 is not affected by the anchor point shear force and remains in a horizontal position.

[0033] Based on the above implementation, when the direction of the anchor point shear force is along the negative y-axis, the four fixed anchor points (anchor points 302, 304, 306, and 308) deform under the action of the shear force. The upper side of the anchor point moves upward along the z-axis, and the lower side moves downward along the z-axis, resulting in an inclined state. Elastic beam structures 312 and 313 are connected to the upper sides of anchor points 302 and 304, respectively, transmitting the positive z-direction displacement of the anchor points to the first elastic straight beam 322. Elastic beam structures 316 and 317 are connected to the lower sides of anchor points 306 and 308, respectively, transmitting the negative z-direction displacement of the anchor points to the first elastic straight beam 326. Therefore, the cross structure of the second elastic element can be considered as being acted upon by a torque M1 around a horizontal dashed line. On the other hand, short beams 332 and 334 are connected to the lower sides of anchor points 302 and 304 respectively, transmitting the negative z-direction displacement of the anchor points to the first elastic straight beam 322; short beams 336 and 338 are connected to the upper sides of anchor points 306 and 308 respectively, transmitting the positive z-direction displacement of the anchor points to the first elastic straight beam 326. The cross structure of the second elastic element can be regarded as being subjected to a torque M2 opposite to the direction of torque M1. The final result is that torques M1 and M2 cancel each other out, so that the rigid frame 360 ​​of the anchoring assembly 301 is not affected by the shear force of the anchor points and remains in a horizontal position.

[0034] In another specific implementation, refer to Figure 7 This is a schematic diagram of another anchoring component for the Z-axis accelerometer provided in an embodiment of this application. Figure 7 As shown, a first stress relief hole 350 is made at the intersection of the second elastic element of the anchoring assembly 301. The first stress relief hole 350 is preferably a round hole to avoid excessive stress at the connection between the third elastic element and the second elastic element.

[0035] Furthermore, in the second elastic element, second stress relief holes (352, 354, 356, 358) are formed in the middle regions (corresponding to the connection between the first and second elastic elements) of each of the first elastic beams 322, 324, 326, and 328. These second stress relief holes are symmetrically distributed about the center of the anchoring assembly. Preferably, the second stress relief holes are elongated holes extending along the length of the first elastic beam to avoid excessive stress at the connection between the first and second elastic elements. The presence of stress relief holes effectively improves the uniformity of stress distribution within the structure, significantly enhancing the accelerometer's impact resistance.

[0036] Based on the above implementation methods, the design principles and effects of the embodiments of this application will be explained below using displacement cloud diagrams of accelerometers.

[0037] Figure 8The displacement contour plot of the Z-axis accelerometer provided in this embodiment of the application under the action of anchor point shear force in the X direction. Figure 8 As shown, the deformation of the Z-axis accelerometer under the action of anchor point shear force is simulated. A Z-direction displacement of 1 nm is specified on the left side and a Z-direction displacement of -1 nm is specified on the right side of the four anchor points (anchor points 302, 304, 306, and 308) of the sensitive structure layer 3. It can be seen that the Z-axis accelerometer provided in this embodiment can effectively resist the anchor point shear force in the X direction. The first mass block 380a and the second mass block 380b do not produce a large Z-direction displacement following the anchor point deformation. The outer displacement is only about 1 nm, which is much smaller than the 25 nm of the Z-axis accelerometer of a single anchor point. The influence on the zero bias of the accelerometer is greatly reduced.

[0038] Figure 9 The displacement contour plot of the Z-axis accelerometer anchoring structure provided in this embodiment of the application under the action of anchor point shear force in the X direction. Figure 9 As shown, the L-shaped elastic beam structure design of the first elastic element of the anchoring assembly 301 can effectively absorb the energy of the anchor point shear deformation in the X direction. Through torque cancellation, the frame 360 ​​of the anchoring assembly 301 is maintained in a relatively horizontal position, with a Z-direction displacement of only 0.1 nm. Compared with a single anchor point structure, the anchoring assembly 301 can effectively isolate the influence of the X-direction anchor point shear force on the mass block of the Z-axis accelerometer.

[0039] Figure 10 The displacement contour plot of the Z-axis accelerometer provided in this embodiment of the application under the action of anchor point shear force in the Y direction. Figure 10 As shown, the deformation of the Z-axis accelerometer under the action of anchor point shear force is simulated. A Z-direction displacement of 1 nm is specified on the upper side and a Z-direction displacement of -1 nm is specified on the lower side of the four anchor points (anchor point 302, anchor point 304, anchor point 306, anchor point 308) of the sensitive structure layer 3. It can be seen that the Z-axis accelerometer provided in this embodiment can effectively resist the anchor point shear force in the Y direction. The first mass block 380a and the second mass block 380b do not produce a large Z-direction displacement with the anchor point deformation. The outer displacement is only about 1 nm, which is much smaller than the 25 nm of the traditional Z-axis accelerometer. The influence on the zero bias of the accelerometer is greatly reduced.

[0040] Figure 11 The displacement contour plot of the Z-axis accelerometer anchoring structure provided in this embodiment of the application under the action of anchor point shear force in the Y direction. Figure 11As shown, the L-shaped elastic beam structure design of the first elastic element of the anchoring assembly 301 can effectively absorb the energy of the anchor point shear deformation in the Y direction. Through torque cancellation, the frame 360 ​​of the anchoring assembly 301 is maintained in a relatively horizontal position, with a Z-direction displacement of only 0.1 nm. Compared with the single anchor point structure, this anchoring structure can effectively isolate the influence of the Y-direction anchor point shear force on the mass block of the Z-axis accelerometer.

[0041] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0043] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. An accelerometer, characterized in that, include: Substrate, wherein a detection layer is present on the surface of the substrate; An anchoring assembly is disposed on the substrate; the anchoring assembly has a plurality of anchor points symmetrically distributed along its center in the XY plane; A mass block is connected to the anchoring assembly via a connecting arm and suspended above the substrate; the mass block is configured to form a detection capacitance with the detection layer and generate Z-axis displacement under Z-axis acceleration. The anchoring component is configured to suppress the transmission of anchor shear force in the X and / or Y directions at the anchor point to the mass block; the XY plane is parallel to the substrate surface, and the Z axis is perpendicular to the XY plane.

2. The accelerometer according to claim 1, characterized in that, The anchoring component includes: A frame is circumferentially arranged along the plurality of anchor points and connected to the connecting arm; An elastic component connects the anchor point and the frame, and both the elastic component and the anchor point are symmetrically distributed along the center of the frame in the XY plane; the elastic component is configured to counteract the anchor point shear force in the X direction and / or Y direction, so that the frame remains parallel to the XY plane.

3. The accelerometer according to claim 2, characterized in that, The elastic component includes a first elastic element, a second elastic element, a third elastic element, and a fourth elastic element; The first elastic element extends circumferentially along each anchor point and connects the anchor point and the second elastic element; The second elastic element is arranged between adjacent anchor points and converges at the center of the anchoring assembly; The third elastic element connects the corner of the anchor point near the center of the anchoring assembly to the intersection of the second elastic element; The fourth elastic element is arranged around the periphery of the plurality of anchor points and connects the second elastic element and the frame.

4. The accelerometer according to claim 3, characterized in that, The first elastic element includes a plurality of elastic beam structures; each elastic beam structure includes an L-shaped first elastic beam and a second elastic beam that are interconnected; the first elastic beam is arranged along the X or Y direction, and the second elastic beam is arranged perpendicular to the first elastic beam; the first elastic beam and the second elastic beam are respectively located on adjacent sides of the same anchor point; one end of the first elastic beam is connected to the corresponding anchor point, and one end of the second elastic beam is connected to the adjacent second elastic element.

5. The accelerometer according to claim 3, characterized in that, The second elastic element includes a plurality of first elastic straight beams, which are arranged along the X or Y direction; the plurality of first elastic straight beams intersect and connect at the center of the anchoring assembly; the connection points of the first elastic elements on both sides of the first elastic straight beams and the first elastic straight beams are in the same X or Y direction.

6. The accelerometer according to claim 4, characterized in that, The fourth elastic element includes a plurality of second elastic straight beams connected end to end, the second elastic straight beams being arranged along the X or Y direction; each second elastic straight beam having a gap between itself and the adjacent frame and being connected to the frame at the end-to-end connection; each second elastic straight beam being connected to the adjacent first elastic straight beam and being perpendicular to each other.

7. The accelerometer according to any one of claims 3-6, characterized in that, The elastic component is provided with at least one stress relief hole.

8. The accelerometer according to claim 7, characterized in that, A first stress relief hole is provided at the intersection of the second elastic elements; and / or, a plurality of second stress relief holes are provided on the second elastic elements, the plurality of second stress relief holes being symmetrically distributed about the center of the anchoring assembly; each second stress relief hole is arranged at a connection point between the first elastic element and the second elastic element that is close to it.

9. The accelerometer according to claim 1, characterized in that, The connecting arm has at least two arms, which are arranged along the Y direction on both sides of the anchoring component and are symmetrically distributed about the center of the anchoring component; the connection between the connecting arm and the mass block and the connection between the connecting arm and the anchoring component are provided with transition chamfers.

10. The accelerometer according to claim 9, characterized in that, The connecting arm is provided with symmetrical auxiliary beams that extend along the Y direction on both sides; the auxiliary beams are connected to the connection between the connecting arm and the anchoring assembly.

11. The accelerometer according to claim 1, characterized in that, The mass block includes a first mass block and a second mass block located on both sides of the anchoring component and arranged along the X direction; the second mass block has an opening near the anchoring component.

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