Anchoring structure for mems accelerometer with curved offset displacement suppression

Abstract

Microelectromechanical systems (MEMS) accelerometers include a test mass that translates out of the MEMS device plane in response to forces of interest, such as z-axis linear acceleration. The test mass is a suspension spring-mass system assembly anchored to both a cover substrate layer and a base substrate layer by an anchoring system. The anchoring system includes a central anchor that is mechanically anchored only to the cover layer, while two adjacent anchors are located on opposite sides of the central anchor and are at least anchored to the base substrate, having an electrical connection to the processing circuitry system of the base substrate. Compliant springs connect the central anchor to the two adjacent anchors in a manner that allows the anchoring system to absorb stresses such as shear forces applied during system packaging, assembly, and use of the final product.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 601,483, filed November 21, 2023, entitled “Anchoring Structure for Z-axis MEMS Accelerometers with bend offset shift rejection”, and U.S. Patent Application No. 18 / 896,555, filed September 25, 2024, entitled “Anchoring Structure for MEMS Accelerometers with Bend Offset Shift Rejection”, each of which is incorporated herein by reference in its entirety for all purposes. Background Technology

[0003] Numerous items, such as smartphones, smartwatches, tablets, cars, drones, appliances, aircraft, motion-assisted devices, and game controllers, can utilize sensors such as microelectromechanical systems (MEMS) sensors during their operation. In many applications, various types of motion sensors, such as accelerometers and gyroscopes, can be analyzed independently or collaboratively to determine a range of information for a specific application. For example, gyroscopes and accelerometers can be used in gaming applications (e.g., smartphones or game controllers) to capture complex user movements; drones and other aircraft can determine orientation based on gyroscope measurements (e.g., roll, pitch, and yaw); and vehicles can utilize measurements to determine direction (e.g., for dead reckoning) and safety (e.g., to identify slippage or rollover conditions).

[0004] As MEMS inertial sensors are increasingly used in more and more applications and devices, there is a need to continuously improve the accuracy and consistency of MEMS sensor output. Many causes of MEMS inertial sensor inaccuracies are not due to the design or manufacturing process of the MEMS inertial sensor, but rather to forces applied to the MEMS inertial sensor during assembly with other components of the end-use device or during use of the end-use device. For example, various forces such as compressive and shear forces can be applied to one or more layers of the MEMS inertial sensor, such as via a cover substrate layer and / or a base substrate layer. These forces transfer to the operational MEMS layers of the MEMS inertial sensor and can cause a shift in the stationary position of components such as a proof mass, resulting in an undesirable offset signal that masks or modifies the signal measured in response to the forces of interest. This offset can be particularly severe in cases where shear or bending forces are applied to the MEMS layers of an out-of-plane (e.g., z-axis) accelerometer. Summary of the Invention

[0005] In embodiments of this disclosure, a microelectromechanical system (MEMS) sensor includes a cover substrate, a base substrate, a first anchor coupled to the cover substrate, a plurality of second anchors coupled to the base substrate, and a suspended spring-mass system positioned within a MEMS layer between the base substrate and the cover substrate. The suspended spring-mass system includes a test mass block, a first anchoring portion coupled to the cover substrate via the first anchor, a second anchoring portion coupled to the base substrate via a first second anchor of the plurality of second anchors, and a third anchoring portion coupled to the base substrate via a second second second anchor of the plurality of second anchors, wherein the second and third anchoring portions are located on opposite sides of the first anchoring portions. The suspended spring-mass system also includes a first compliant spring connecting the first anchoring portion to the second anchoring portion, a second compliant spring connecting the first anchoring portion to the third anchoring portion, and a plurality of shock-absorbing springs coupled between the first anchoring portion and the test mass block.

[0006] In embodiments of this disclosure, a microelectromechanical system (MEMS) sensor includes a cover substrate, a base substrate, a first anchor coupled to the cover substrate, a plurality of second anchors coupled to the base substrate, and a suspended spring-mass system positioned within a MEMS layer between the base substrate and the cover substrate. The suspended spring-mass system includes a test mass suspended from the first and second anchors via one or more springs, a first anchoring portion coupled to the cover substrate via the first anchor, a second anchoring portion coupled to the base substrate via a first second anchor of the plurality of second anchors, and a third anchoring portion coupled to the base substrate via a second second second anchor of the plurality of second anchors, wherein the second and third anchoring portions are located on opposite sides of the first anchoring portions. The suspended spring-mass system also includes a first compliant spring of the one or more springs surrounding the second anchoring portion and connecting the first anchoring portion to the second anchoring portion, and a second compliant spring of the one or more springs surrounding the third anchoring portion and connecting the first anchoring portion to the third anchoring portion.

[0007] In embodiments of this disclosure, a microelectromechanical system (MEMS) sensor includes a cover substrate, a base substrate, a first anchor coupled to the cover substrate, a plurality of second anchors coupled to the base substrate, and a suspended spring-mass system positioned within a MEMS layer between the base substrate and the cover substrate. The suspended spring-mass system includes a test mass block, a first anchoring portion coupled to the cover substrate via the first anchor, a plurality of second anchoring portions coupled to the base substrate via corresponding second anchors, a shear force reduction component for isolating shear forces at the first anchoring portion and the plurality of second anchoring portions, and an impact absorption component located between the first anchoring portion and the test mass block for absorbing impact forces at the first anchoring portion. Attached Figure Description

[0008] The above and other features, nature, and various advantages of this disclosure will become clearer when considered in conjunction with the accompanying drawings, in which: Figure 1 An illustrative MEMS system according to embodiments of the present disclosure is shown; Figure 2A The illustration shows a top view of the MEMS layer of an exemplary out-of-plane accelerometer according to an embodiment of the present disclosure; Figure 2B The illustration shows an embodiment according to the present disclosure. Figure 2A A top view of an exemplary out-of-plane accelerometer MEMS layer anchoring system; Figure 2C The illustration shows an embodiment according to the present disclosure. Figure 2A A cross-sectional view of an exemplary out-of-plane accelerometer; Figure 2D The illustration depicts a shear force subjected to an embodiment of the present disclosure. Figure 2A A cross-sectional view of an exemplary out-of-plane accelerometer; Figure 2E The illustration depicts an embodiment of the present disclosure undergoing [a process / condition]. Figure 2D shear force Figure 2A A top view of an exemplary out-of-plane accelerometer MEMS layer anchoring system; Figure 2F The illustration depicts the impact force subjected to an embodiment according to the present disclosure. Figure 2A A top view of an exemplary out-of-plane accelerometer MEMS layer anchoring system; Figure 3A The illustration shows a top view of another exemplary anchoring system for a MEMS layer of an exemplary out-of-plane accelerometer according to an embodiment of the present disclosure; Figure 3B The illustrations depict embodiments of the present disclosure including... Figure 3A A cross-sectional view of an exemplary out-of-plane accelerometer for an anchoring system; and Figure 4 The illustration shows exemplary steps of operating an out-of-plane accelerometer with offset displacement suppression according to an embodiment of the present disclosure. Detailed Implementation

[0009] MEMS sensors, such as MEMS accelerometers, include a test mass block fabricated within a MEMS layer that responds to forces of interest, such as linear acceleration. While this disclosure will be described in the context of MEMS accelerometers, it should be understood that the anchoring and spring systems of this disclosure can be applied to other MEMS sensors, such as gyroscopes, pressure sensors, magnetometers, or microphones, that have suspended test mass blocks. The test mass block is mechanically suspended, for example, by a series of springs and mass blocks, such that it moves in a specific manner and orientation in response to linear acceleration in a specific direction (e.g., along the x-axis, y-axis, or z-axis). Components of a MEMS layer suspended within and anchored at anchoring regions herein, and including those anchoring regions, are collectively referred to as suspended spring-mass systems. In the described embodiments, a proof mass that translates primarily within the plane of the MEMS relative to a fixed sensing electrode is referred to as an in-plane proof mass, while a mass that moves primarily in the direction of another layer of the sensor (e.g., a base substrate and a cover substrate) relative to a fixed sensing electrode on one or more other layers is referred to as an out-of-plane proof mass. Although these proof masses are configured to move in a specific manner, external forces such as shear forces (e.g., due to encapsulation or use in end-use devices) and impact forces (e.g., dropping from an end-use device including the sensor or other physical impacts) can permanently affect the performance of the MEMS accelerometer, for example, by altering the intended position of the proof mass relative to the sensing electrode due to shear forces or by damaging the proof mass or springs (which alter the proof mass's response to forces of interest) due to impact forces.

[0010] The MEMS layer can be rigidly anchored to a base substrate and / or a cover substrate to suspend active components within the MEMS layer and provide electrical signal paths to the MEMS layer (e.g., from the base substrate including a processing circuitry system). In embodiments of this disclosure, mechanical anchoring portions are mechanically anchored to only one of the substrates (e.g., the cover substrate), while one or more electrical anchoring portions are at least electrically anchored to another substrate (e.g., the base substrate) and may also be mechanically anchored to the same substrate as the mechanical anchoring portions. In a series of springs and mass blocks interconnecting the components of the MEMS layer, the mechanical anchoring portions are positioned closer to the test mass block than the electrical anchoring portions and are located between the electrical anchoring portions and the test mass block.

[0011] A compliant spring is positioned between the electrical anchoring portion and the mechanical anchoring portion. In one example, the electrical anchoring portion is located equidistantly from the mechanical anchoring portion on each side of the mechanical anchoring portion. The compliant spring is relatively thin and extends from the far side of each electrical anchoring portion furthest from the mechanical anchoring portion, surrounds and extends around the electrical anchoring portion, and attaches to the mechanical anchoring portion on the other side. When the package of the MEMS accelerometer (e.g., on a cover substrate and a base substrate to which the MEMS layer is attached via anchors) experiences forces such as shear forces, the compliant spring isolates the movement of the electrical anchors from the mechanical anchors, including, in some cases, allowing the electrical anchoring portion to tilt within the MEMS layer, while the mechanical anchoring portion only translates within the MEMS layer. In this way, even when severe shear forces are applied to the sensor package, the distance of the test mass block relative to the sensing electrodes (e.g., out-of-plane sensing electrodes) remains unchanged.

[0012] Shock-absorbing springs are also located between the mechanical anchoring portion and the inspection quality block. For example, multiple shock-absorbing springs may extend outward from the centrally located mechanical anchoring portion and may be defined by multiple slots within the MEMS layer where material has been removed. The shock-absorbing springs are relatively long compared to their width, and the slots are positioned to the sides and aligned with the shock-absorbing springs. Accordingly, when an impact force is applied to the sensor package, the shock-absorbing springs buckle within the allocated space of the adjacent slots, thereby preventing this force from being transferred from the package to the inspection quality block via anchors to the package (e.g., the base substrate and / or cover substrate).

[0013] Figure 1 An illustrative MEMS system 100 according to an embodiment of the present disclosure is shown. Although Figure 1 The illustrations show specific components, but it should be understood that other suitable combinations of MEMS, processing components, memory, and other circuitry can be utilized depending on the needs of different applications and systems. According to this disclosure, a MEMS system may include a MEMS accelerometer 102, such as a z-axis accelerometer having a test mass that moves out of plane in response to z-axis acceleration, and additional sensors 108, such as additional MEMS accelerometers, one or more MEMS gyroscopes, MEMS pressure sensors, and additional MEMS or other sensors.

[0014] The processing circuitry system 104 may include one or more components that provide processing based on the requirements of the MEMS system 100. In some embodiments, the processing circuitry system 104 may include hardware control logic that may be integrated within the sensor chip (e.g., on the substrate of the MEMS accelerometer 102 and / or other sensor 108, or on a portion of the chip adjacent to the MEMS accelerometer 102 or other sensor 108) to control the operation of the MEMS accelerometer 102 or other sensor 108 and perform aspects of processing for the MEMS accelerometer 102 or other sensor 108. In some embodiments, the MEMS accelerometer 102 and other sensor 108 may include one or more registers that allow modification (e.g., by modifying register values) of aspects of the operation of the hardware control logic. In some embodiments, the processing circuitry system 104 may also include a processor, such as a microprocessor that executes software instructions, for example, stored in memory 106. The microprocessor can control the operation of the MEMS accelerometer 102 by interacting with the hardware control logic and processing signals received from the MEMS accelerometer 102. The microprocessor may interact with other sensors 108 in a similar manner. In some embodiments, some or all of the functions of the processing circuitry 104 and, in some embodiments, the memory 106 may be implemented on an application-specific integrated circuit (“ASIC”) and / or a field-programmable gate array (“FPGA”).

[0015] Although in some embodiments ( Figure 1(Not shown in the figure) The MEMS accelerometer 102 or other sensor 108 can communicate directly with external circuitry (e.g., via a serial bus or a direct connection to sensor outputs and control inputs). However, in embodiments, the processing circuitry 104 can process data received from the MEMS accelerometer 102 and other sensors 108 and communicate with external components via a communication interface 110 (e.g., a Serial Peripheral Interface (SPI) or I2C bus, a Controller Area Network (CAN) or Local Interconnect Network (LIN) bus in automotive applications, or a suitable wired or wireless communication interface known in the art in other applications). The processing circuitry 104 can convert signals received from the MEMS accelerometer 102 and other sensors 108 into appropriate units of measurement (e.g., based on settings provided by other computing units transmitted via the communication interface 110) and perform more complex processing to determine measurements such as orientation or Euler angles, and in some embodiments to determine whether a specific activity (e.g., walking, running, braking, slipping, rolling, etc.) is occurring from the sensor data. In some embodiments, some or all of the conversion or calculation may occur on the hardware control logic of the MEMS accelerometer 102 or other sensor 108 or on-chip processing.

[0016] In some embodiments, during a process that may be referred to as sensor fusion, certain types of information can be determined based on data from multiple MEMS gyroscopes 102 and other sensors 108. By combining information from various sensors, it is possible to accurately determine information useful in a variety of applications, such as image stabilization, navigation systems, automotive control and safety, dead reckoning, remote control and gaming devices, motion sensors, 3D cameras, industrial automation, and many others.

[0017] In embodiments of this disclosure, MEMS sensors, such as MEMS accelerometers (e.g., out-of-plane z-axis accelerometers, or in-plane x-axis or y-axis accelerometers), have anchoring structures that absorb externally applied forces to prevent such forces from affecting the rest position of associated sensing structures, such as one or more test mass blocks configured to move relative to fixed sensing electrodes in response to acceleration in a particular direction (e.g., out-of-plane for z-axis accelerometers, or in-plane for x-axis or y-axis accelerometers). The anchoring structures include compliant springs that absorb externally applied shear or lateral forces, caused, for example, by corresponding laterally applied forces (e.g., in opposite directions, or applied only to one of the cover or base substrates) on a cover (e.g., cap or lid) substrate and a base (e.g., bottom, processing, or CMOS) substrate, such as those that may occur during the manufacture and packaging of the MEMS accelerometer 102, during integration of the MEMS accelerometer 102 into a final-use product, or during use of the final-use product. The anchoring structure also includes shock-absorbing springs that absorb forces caused by impacts, such as during the use of the end-use product or when the end-use product is dropped or otherwise experiences a relatively short-duration, high-force event. The shock-absorbing springs are located between the MEMS accelerometer's test mass and the main mechanical anchor, ensuring that impact forces are absorbed within the anchoring structure and not mechanically transmitted to the test mass.

[0018] Figure 2A A top view of a MEMS layer of an exemplary out-of-plane accelerometer according to an embodiment of the present disclosure is illustrated. While Figure 2 will be described in the context of system components including a z-axis MEMS accelerometer with an out-of-plane test mass block located within a MEMS layer of a three-layer MEMS sensor architecture and specific applications, it should be understood that the anchoring system of the present disclosure can be utilized with a variety of other sensors, such as MEMS gyroscopes and in-plane sensing (e.g., x-axis or y-axis) MEMS accelerometers, to prevent shear and impact forces from affecting the static position of the test mass block. As another example, while the present disclosure will be discussed in the context of a MEMS structure including three main structural layers (e.g., a cover substrate, a base substrate, and a MEMS layer bonded between the cover substrate and the base substrate), in some embodiments, other MEMS sensor configurations (e.g., having intermediary layers and / or integration layers) can utilize the anchoring structures of the present disclosure (e.g., having mechanical anchoring of the MEMS layer to one layer or substrate and electrical anchoring to another layer or substrate).

[0019] exist Figure 2A In an exemplary embodiment, the MEMS accelerometer includes an anchoring system or system (e.g., as in...) Figure 2BFurther illustrated in section 2C are the fixed MEMS layer portions 206A and 206B adjacent to and coupled to the anchoring system, the inspection mass block 202, the sensing springs 204A and 204B coupled between the anchoring system and the inspection mass block 202, and the fixed region 201. Additionally, section line 2C shows... Figure 2C And the corresponding section lines with accompanying descriptions. Although in Figure 2A The illustrations and descriptions of these specific components are provided, but it should be understood that components may be added, removed, replaced, or modified in accordance with this disclosure. For example, in some embodiments, the fixing MEMS layer portion may not be included within the MEMS layer, or may be positioned away from the shock-absorbing spring (e.g., not with). Figure 2B More detailed illustrations of shock-absorbing springs and Figure 2A The sensing springs are partially adjacent.

[0020] exist Figure 2A In the embodiments, each of the two fixed MEMS layer portions 206A and 206B extends from the anchoring system 2B as a continuous layer of material, such that the fixed MEMS layer portion is integral with the anchoring system. In this way, movement of the anchoring system due to externally applied forces (such as lateral movement within the MEMS layer) is also transferred to the fixed MEMS layer portions 206A and 206B. In the context of this disclosure, the anchoring system 2B prevents external forces (such as shear forces) from tilting the entire anchoring system, such that a portion of the anchoring system connected to the fixed MEMS layer portions 206A and 206B does not tilt out of plane in response to such forces, and thus the fixed MEMS layer portions 206A and 206B also do not tilt out of plane. The fixed MEMS layer portions remain stationary in response to the forces of interest. It will be noted that, although in Figure 2A The illustration shows a specific number of fixed MEMS layer portions 206A and 206B with a particular shape and configuration, but other numbers, configurations and shapes of fixed MEMS layer portions conforming to this disclosure may be used, for example, by fixing such fixed MEMS layer portions within the MEMS layer to portions of an anchoring system 2B as described herein, which is isolated from external forces (e.g., shear forces) via compliant springs.

[0021] The anchoring system 2B is also connected to the inspection mass 202 via corresponding suspension springs 204A and 204B, which extend within the MEMS layer through a portion of the inspection mass 202 and have torsional compliance (e.g., about the x-axis) to allow the inspection mass 202 to rotate out-of-plane in response to linear acceleration along the z-axis. Sensing electrodes (not in...) Figure 2AThe illustrated test mass 202 (located below the test mass block, e.g., below the upper and lower portions of the test mass block) forms a capacitive sensor (e.g., a differential sensor) with the test mass block 202. It should be understood that the illustrated configuration of the test mass block 202 and suspension springs 204A and 204B is merely exemplary, and various test mass blocks, springs, and other configurations can be utilized to allow the test mass block to move out of plane in response to z-axis linear acceleration. In the context of this disclosure, the test mass block is connected (e.g., via springs) within the MEMS layer to a portion of the anchoring system 2B, as described herein, via compliant springs and isolated from external forces (e.g., shear forces).

[0022] Figure 2B The illustration shows an embodiment according to the present disclosure. Figure 2A A top view of an exemplary out-of-plane accelerometer MEMS layer anchoring system. While the anchoring system described herein can be implemented with various components and configurations, and components may be modified, omitted, or added in different embodiments conforming to this disclosure (e.g., simultaneously maintaining the isolation of(one or more) mechanical anchor portions from(one or more) electrical anchor portions via compliant springs, and / or providing shock-absorbing springs between(one or more) mechanical anchor portions and the moving components of the MEMS layer), in an embodiment, anchoring system 2B may include mechanical anchors 210, mechanical anchor portions 211, mechanical anchors 212A and 212B, electrical anchors 214A and 214B, compliant springs 216A and 216B, electrical anchor portions 218A and 218B, isolation grooves 220A and 220B, shock-absorbing springs 222A / 222B / 222C / 222D, and shock-absorbing grooves 224A / 224B / 224C / 224D. Figure 2B In one embodiment, the impact absorbing springs 222A / 222B / 222C / 222D and the impact absorbing grooves 224A / 224B / 224C / 224D are each positioned equidistant from the mechanical anchor 210.

[0023] Mechanical anchoring portion 211 is anchored to another layer (e.g., cover substrate) of the MEMS accelerometer via mechanical anchor 210. Figure 2B In this embodiment, the mechanical anchor 210 is a circular anchor that mechanically attaches and suspends the mechanical anchor portion 211 of the MEMS layer to the cover substrate. The mechanical anchor portion 211 is not connected to the base substrate, therefore its position within the MEMS package of the MEMS accelerometer is primarily based on the position of the cover substrate. Although in Figure 2BThe mechanical anchor 210 is illustrated as circular and is depicted as having a specific proportion relative to the mechanical anchor portion 211 and other components of the anchoring system. However, it should be understood that the mechanical anchor can be suitably implemented in various shapes and sizes to provide robust mechanical suspension of the MEMS layer. While the mechanical anchor portion 211 is illustrated as having a generally rectangular shape and proportion relative to the other components of the anchoring system, it should be understood that the mechanical anchor portion can be implemented in various ways according to this disclosure (e.g., shapes such as elliptical, circular, square, polygonal, irregular shapes; different sizes; etc.). Furthermore, although in Figure 2B The figure shows a single mechanical anchoring part 211, but it should be understood that multiple mechanical anchoring parts 211 can be used and positioned at different locations within the anchoring system, while maintaining isolation from shear forces via appropriately positioned and configured compliant springs and maintaining impact absorption via appropriately positioned and configured impact absorbing springs.

[0024] exist Figure 2B In an exemplary embodiment, electrical anchoring portions 218A and 218B are located on each side of mechanical anchoring portion 211 and are equidistant from mechanical anchoring portion 211. In other embodiments, different numbers of electrical anchoring portions 218A and 218B may be used, and the electrical anchoring portions may be located at various relative positions to one or more mechanical anchoring portions while maintaining isolation from external forces based on the configuration and position of the compliant springs. Each of the electrical anchoring portions 218A and 218B is anchored to a base substrate via corresponding electrical anchors 214A and 214B, the base substrate including an electrical processing circuitry such as a CMOS circuitry system. Figure 2B In some embodiments, the electrical anchoring portions 218A and 218B are also mechanically anchored to the cover plate via mechanical anchors 212A and 212B, but in some embodiments (e.g., as...) Figure 3A and Figure 3B As illustrated in the figures, electrical anchoring portions 218A and 218B may not include mechanical anchors. Although electrical anchoring portions 218A and 218B are illustrated as having an generally elliptical or polygonal shape and relative proportion to other components of the anchoring system, it should be understood that electrical anchoring portions may be implemented in various ways according to this disclosure (e.g., shapes such as rectangles, circles, squares, polygons, irregular shapes; different sizes; etc.).

[0025] Compliant springs 216A and 216B are connected between the mechanical anchoring part 211 and the corresponding electrical anchoring parts 218A and 218B. Figure 2BIn the embodiment illustrated in the figure, each compliant spring 216A and 216B is connected to the side of the electrical anchor portion 218A or 218B opposite to the mechanical anchor portion 211 along the y-axis, thereby providing a surrounding portion around the respective electrical anchor portion 218A or 218B, and each compliant spring 216A and 216B is connected to the mechanical anchor portion 211 closer to it along the y-axis. Compared to the dimensions of the anchor portion, the width of the compliant springs 216A and 216B in the MEMS plane (i.e., the xy plane) is relatively thin, such that when the electrical anchor portions 218A and 218B are displaced relative to the mechanical anchor portion (e.g., in response to shear forces), the compliant springs buckle both in and out of the plane. Although the compliant springs 216A and 216B are illustrated as extending from the side of the electrical anchor portion 218A or 218B opposite to the mechanical anchor portion 211, and extending to surround the electrical anchor portion 218A or 218B and attach to the mechanical anchor portion 211 on the other side, it should be understood that other configurations can similarly facilitate the isolation of external forces between the electrical anchor portion and the mechanical anchor portion.

[0026] Shock-absorbing springs 222A / 222B / 222C / 222D are connected at one end to a mechanical anchoring portion 211 and at the opposite end to a relatively thick interconnected MEMS layer portion, which in turn is connected to fixed MEMS layer portions 206A and 206B and suspension springs 204A and 204B. Suspension springs 204A and 204B are further connected to an inspection mass block 202 (not in...). Figure 2B (as shown in the diagram), and in this way, the test mass 202 is suspended from the mechanical anchor 210 via the mechanical anchor portion 211 and the intervening impact absorbing springs 222A and 222B. The impact absorbing springs 222A / 222B / 222C / 222D are defined by the slots of the isolation slots 220A and 220B, the impact absorbing slots 224A / 224B / 224C / 224D, and the slots of the adjacent (e.g., separated by slots without intervening components) compliant springs 216A and 216B. Although in Figure 2BThe illustration shows a specific number and orientation of shock-absorbing springs, but in other embodiments, different numbers (e.g., more or fewer) of shock-absorbing springs may be in different orientations, including based on the number and shape of mechanical and electrical anchoring portions. Shock-absorbing springs 222A / 222B / 222C / 222D have a certain thickness and adjacent slotting, which allows the springs to buckle within the adjacent slots when an impact (e.g., in any direction) occurs on the MEMS accelerometer package and is transmitted to the MEMS layer via mechanical and / or electrical anchoring. Accordingly, the forces transmitted to suspension springs 204A and 204B and the test mass block 202 are limited by the shock absorption of shock-absorbing springs 222A / 222B / 222C / 222D.

[0027] Figure 2C The illustration shows an embodiment according to the present disclosure. Figure 2A A cross-sectional view of an exemplary out-of-plane accelerometer 200. For ease of illustration, details are not shown in the image. Figure 2C The diagram illustrates all components of the out-of-plane accelerometer 200 (e.g., the fixed MEMS layer portion, the test mass block within the MEMS layer 232, and...). Figure 2B (Components of the anchoring area shown in the diagram). Figure 2C The encapsulation and interconnection of MEMS layer 232, cover substrate layer 230, and base substrate layer 234 are also not illustrated. Although in Figure 2C The diagram illustrates specific components with specific configurations, but it should be understood that more can be used for different components. Figure 2C To make replacements, additions, omissions, or other modifications, for example, such as for... Figure 2A and Figure 2B As described.

[0028] Figure 2C The illustration shows a cover substrate 230 positioned above and parallel to the MEMS layer 232, and a base substrate 234 positioned below and parallel to the MEMS layer 232. The layer thicknesses and interlayer distances shown are for illustrative purposes only, and it will be understood that layer thicknesses and relative distances can be modified based on the materials used, sensor type, etc. Figure 2C In an exemplary embodiment, the cover substrate 230 does not include active electrical components or circuit systems, while the base substrate 234 includes active processing circuit systems (including sensing electrodes 236 and 238), and analog and digital processing circuit systems such as amplifiers, filters, and digital processing circuit systems (not included in the exemplary embodiment). Figure 2C(See diagram). Accordingly, anchors 214A and 214B, which connect the base substrate layer 234 to the MEMS layer 232 (e.g., at electrical anchoring portions 218A and 218B), provide electrical signals propagating through the MEMS layer, such as drive signals having a carrier frequency for sensing the movement of the test mass block 202 relative to the sensing electrodes 236 and 238 (e.g., out-of-plane movement of portions of the test mass block 202 relative to the sensing electrodes 236 and 238). Figure 2C In the illustrated embodiment, mechanical anchors 212A and 212B are also connected to an anchoring system 2B above electrical anchors 214A and 214B (e.g., at electrical anchoring portions 218A and 218B), thereby providing a mechanical connection to the cover substrate 230. As can be seen with respect to mechanical anchor 210 connected to anchoring system 2B (e.g., at mechanical anchoring portion 211), there is no corresponding electrical anchoring portion connected to the MEMS layer 232 below mechanical anchor 210.

[0029] Figure 2D The illustration depicts a shear force subjected to an embodiment of the present disclosure. Figure 2A A cross-sectional view of an exemplary out-of-plane accelerometer. Figure 2D The components can be modified, for example, relative to Figures 2A-2C As described. In Figure 2D In the example illustrated, shear forces 240 and 242 are applied to the MEMS accelerometer 200 in a countervailing direction, with shear force 240 applied to the cover substrate 230 in the positive y-direction and shear force 242 applied to the base substrate 234 in the negative y-direction. The illustrated forces are merely exemplary, and it should be understood that forces can be experienced independently by any layer or substrate of the MEMS accelerometer 200 and in various directions (e.g., in the xy-plane, and / or compressive z-axis force). The exemplary shear forces 240 and 242 may, for example, correspond to shear forces experienced due to encapsulation with other components in the end-use device; however, it should be understood that various underlying causes for shear forces and other forces may occur in different configurations and applications. It will be understood that in Figure 2D The lateral movement and tilt shown in the diagram may be emphasized for illustrative purposes, and the lateral movement and tilt caused by the different forces experienced during operation may be substantially smaller than those shown in the diagram.

[0030] like Figure 2DAs illustrated, the directions of the counter-shear forces 240 and 242 cause the cover substrate 230 to shift laterally in the positive y-direction and the base substrate 234 to shift laterally in the negative y-direction. These shifts also affect the position of the anchors connected to the corresponding layers / substrates. Mechanical anchors 212A and 212B are mechanically connected to electrical anchors 214A and 214C via MEMS layer 232 (e.g., via electrical anchor portions 218A and 218B of anchoring system 208 within MEMS layer 232), causing mechanical anchors 212A and 212B and electrical anchors 214A and 214B to tilt with the lateral shift of the corresponding cover substrate 230 and base substrate 234. However, mechanical anchor 210 translates laterally within MEMS layer 232 with cover substrate 230, causing corresponding components such as fixed MEMS layer portions 206A and 206B and inspection quality block 202 to translate with mechanical anchor 210 and cover substrate 230. Accordingly, although the functional sensing components within the MEMS layer may be laterally translated, they maintain complete coverage of the sensing electrodes 236 and 238 (e.g., based on the relative size and position of the test mass block 202 and the sensing electrodes 236 and 238), while the z-axis distance between the test mass block 202 and the sensing electrodes 236 and 238 (e.g., corresponding to the initial capacitance) remains unchanged.

[0031] Figure 2E The illustration depicts an embodiment of the present disclosure undergoing [a process / condition]. Figure 2D shear force Figure 2A A top view of the anchoring system for the MEMS layer of an exemplary out-of-plane accelerometer. As indicated by the upward and downward arrows superimposed on the electrical anchoring portions 218A and 218B, the MEMS layer associated with the electrical anchoring portions 218A and 218B tilts in response to shear forces 240 and 242. However, compliant springs 216A and 216B effectively absorb this tilting via a connection between the electrical anchoring portions 218A and 218B on opposite sides relative to the mechanical anchoring portion 210. Accordingly, the mechanical anchoring portion 211 does not tilt with the electrical anchoring portions 218A and 218B, but is instead allowed to move in the positive y-direction with the mechanical anchor 210.

[0032] Figure 2F The illustration depicts the impact force subjected to an embodiment according to the present disclosure. Figure 2A A top view of an exemplary out-of-plane accelerometer's MEMS layer anchoring system. Impact forces can be the result of various underlying events and are typically encountered during the use of the end-use device, such as drops or some other impact. Figure 2FIn the exemplary embodiment illustrated in the figure, the example impact force 250 is illustrated as being oriented in the xy plane (e.g., in the positive y direction and the negative x direction), for example, caused by an impact occurring at the upper left corner of the device to be used. Figure 2F As illustrated, the anchoring region 211 can be temporarily displaced in the direction of the impact force (e.g., as shown by the movement of the mechanical anchor 210 and the anchoring region 211 in the direction of the impact force). However, the isolation grooves 220A / 220B and the impact absorption grooves 224A / 224B / 224C / 224D together with the impact absorption springs 222A / 222B / 222C / 222D temporarily expand or contract (e.g., as shown in the figure). Figure 2F As illustrated, the shape and dimensions of these flexible components undergo temporary changes. This movement does not transfer to moving components such as the fixed MEMS layer sections 206A and 206B, suspension springs 204A and 204B, and the test mass block 202. After these components absorb the impact force and no longer affect the MEMS accelerometer, the components within the anchoring system return to their original positions. Figure 2A The diagram shows its original shape and location.

[0033] Figure 3A A top view of another exemplary anchoring system for the MEMS layer of an exemplary MEMS out-of-plane accelerometer 300 according to an embodiment of the present disclosure is illustrated. Figure 3A In the embodiments, most components are in conjunction with Figure 2B The same method of illustration is used, but the first sub-label number is renumbered to begin with "3" instead of "2" (e.g., inspection quality block 202 is renumbered as inspection quality block 302, etc.). It should be understood that, with... Figure 2B Similarly, in Figure 3A In the embodiments illustrated in the diagram, specific components can be added, removed, and modified according to specific designs, configurations, and applications. Figure 2B In comparison, Figure 3A In the embodiments, electrical anchoring regions 318A and 318B are anchored only to electrical anchors 314A and 314B and are anchored to the base plate via these anchors (not in Figure 3A (See diagram). Therefore, electrical anchoring areas 318A and 318B are not directly connected to the cover plate (e.g., via a similar method). Figure 2B Mechanical anchors 212A and 212B in the middle).

[0034] Therefore, in Figure 3AIn this embodiment, the electrical anchoring regions 318A and 318B are less likely to experience stresses that would cause the electrical anchoring regions to tilt out of plane, such as shear forces that would cause opposing forces applied to the upper cover substrate and the lower base substrate. In the case of such shear forces, a portion of the force applied to the cover substrate will be experienced only by the mechanical anchoring region 311 via the mechanical anchor 310 in the xy plane, while the opposing forces will be experienced only by the electrical anchoring regions 318A and 318B via the electrical anchors 314A and 314B in the opposing directions within the xy plane. The corresponding in-plane forces are absorbed via compliant springs 316A and 316B and therefore do not transfer between the mechanical anchoring regions 311 and the electrical anchoring regions 318A and 318B, such that the moving components of the MEMS accelerometer only shift with the mechanical anchoring region 311 as described herein.

[0035] Figure 3B The illustrations depict embodiments of the present disclosure including... Figure 3A A cross-sectional view of an exemplary out-of-plane accelerometer for an anchoring system. For ease of illustration, all components of the out-of-plane accelerometer 300 (e.g., fixing MEMS layer portions 306A and 306B, the test mass block within MEMS layer 332, and...) are shown. Figure 3A The components in the anchoring area shown in the diagram are not in Figure 3A Specific illustrations in the text, Figure 2B The encapsulation and interconnection of MEMS layer 332, cover substrate layer 330, and base substrate layer 334 are also not illustrated. Although in Figure 3B The diagram illustrates specific components with specific configurations, but it should be understood that more can be used for different components. Figure 3B To make replacements, additions, omissions, or other modifications, for example, such as for... Figure 3A As described.

[0036] Figure 3B The illustration shows a cover substrate 330 positioned above and parallel to the MEMS layer 332, and a base substrate 334 positioned below and parallel to the MEMS layer 332. The layer thicknesses and interlayer distances shown are for illustrative purposes only, and it will be understood that layer thicknesses and relative distances can be modified based on the materials used, sensor type, etc. Figure 3B In an exemplary embodiment, the cover substrate 330 does not include active electrical components or circuit systems, while the base substrate 334 includes active processing circuit systems (including sensing electrodes 336 and 338), as well as analog and digital processing circuit systems such as amplifiers, filters, and digital processing circuit systems (not included in the exemplary embodiment). Figure 3B(See diagram). Accordingly, electrical anchors 314A and 314B, which connect the base substrate layer 334 to the MEMS layer 332 (e.g., at electrical anchor portions 318A and 318B), provide electrical signals propagating through the MEMS layer, such as drive signals having a carrier frequency for sensing the movement of the test mass block 302 relative to the sensing electrodes 336 and 338 (e.g., out-of-plane movement of portions of the test mass block 302 relative to the sensing electrodes 336 and 338). Figure 2C In the embodiment illustrated, only one mechanical anchor 310 is connected to the anchoring system at the mechanical anchoring portion of the anchoring system. Therefore, the only anchoring connection between the MEMS layer 332 and the base substrate 334 is via electrical anchors 314A and 314B to the electrical anchoring portion of the anchoring system, and the only anchoring connection between the MEMS layer 332 and the cover substrate 330 is via the mechanical anchor 310 to the mechanical anchoring portion of the anchoring system. Figure 3A and Figure 3B In the configuration, the anchoring system will behave similarly to Figures 2A-2F The behavior described herein, except that some forces (e.g., shear forces) may be experienced differently by the anchoring system within MEMS layer 232, are still absorbed by compliant springs (e.g., in-plane tilt).

[0037] Figure 4 Exemplary steps of operating an out-of-plane accelerometer with offset displacement suppression according to an embodiment of the present disclosure are illustrated. Although for Figure 4 Specific steps are illustrated in a specific order, but steps may be removed, modified, or replaced, and additional steps may be added in some embodiments, and the order of certain steps may be modified in some embodiments.

[0038] Figure 4 The steps begin at step 402, where operation of a MEMS device, such as an out-of-plane sensing MEMS accelerometer, is initiated. For example, operation of the MEMS accelerometer can be initiated by powering on the end-use device, or it can typically be active during the end-use device's sleep or other low-power modes. In some cases, the sensing of the MEMS accelerometer can be based on a known or expected relative position of one or more test mass blocks relative to a sensing component such as sensing electrodes. Accordingly, certain scaling, offsetting, magnification, transformation, and other operations of the MEMS accelerometer can be utilized to determine linear acceleration. Once operation of the MEMS accelerometer is initiated, Figure 4 Then you can proceed to step 404.

[0039] At step 404, an electrical signal is applied to the MEMS layer of the MEMS accelerometer via an electrical anchor. As described herein, other layers of the MEMS accelerometer may include electrically active processing circuitry and sensing electrodes. The processing circuitry may also provide electrical signals, such as electrically driven or carrier signals, to the MEMS layer via connections to electrically anchored regions of the MEMS layer via the electrical anchor. These signals can then propagate through the MEMS layer (e.g., to fixed MEMS layer portions and test mass blocks) for motion sensing or other purposes (e.g., self-testing). Once the appropriate signal has been propagated to the MEMS layer, Figure 4 Then you can proceed to step 406.

[0040] At step 406, external forces such as shearing or impact forces may be received or present within the MEMS layer via the cover substrate or mechanical anchors, such as those via mechanical anchoring regions of an anchoring system that connects the cover substrate to the MEMS layer. In some embodiments, the external forces are also received within the MEMS layer via the cover substrate through mechanical anchors in electrical anchoring regions of an anchoring system that connects the cover substrate to the MEMS layer. Figure 4 The process can continue to step 408.

[0041] At step 408, external forces may also be received or present within the MEMS layer (e.g., simultaneously) via the base substrate or electrical anchors such as those via electrical anchoring regions of an anchoring system that connects the base substrate to the MEMS layer. Figure 4 The steps can continue to step 410.

[0042] At step 410, if received or present, forces such as shear forces can be absorbed by a compliant spring connecting the mechanical anchoring region and the electrical anchoring region. In an example where the electrical anchoring region is anchored via both electrical and mechanical anchors, the compliant spring can absorb tilting of the electrical anchoring region within the MEMS layer. In an example where the electrical anchoring region is coupled only to the electrical anchor (i.e., only to the base substrate), the compliant spring can absorb in-plane translation between the electrical anchoring portion and the mechanical anchoring portion. Accordingly, the position of the active component of the MEMS accelerometer, which is indirectly connected to the electrical anchoring portion only via the compliant spring and the mechanical anchoring portion, will translate in-plane only with the mechanical anchoring portion without affecting the sensing electrode coverage or the capacitive distance between the sensing electrode and the test mass block or the fixed MEMS layer portion. Figure 4 The steps can continue to step 412.

[0043] At step 412, the sensor may experience an impact force. It should be understood that there is no specific order in which impact and shear forces are received; these forces can be received simultaneously. Figure 4The specific ordering is for illustrative purposes only. If no impact force is experienced, the process can return to step 402. If an impact force is experienced, the process can continue to step 414. At step 414, an impact-absorbing spring positioned to suspend the moving component of the MEMS accelerometer (e.g., between the mechanical anchor portion and the fixed MEMS layer portion and the inspection mass block) absorbs the impact force, such as by buckling in conjunction with an adjacent slot. In this way, even if the mechanical anchor portion experiences an impact force through its connection to the cover plate via the mechanical anchor, the impact force is not transferred to the fixed MEMS layer portion or the inspection mass block, or is transferred by a significantly reduced amount, thereby preventing stress and damage to the components such as by contact between moving components in the plane, contact between movable components and fixed components within the MEMS layer due to in-plane movement, or contact between movable components and fixed components outside the MEMS layer due to out-of-plane movement.

[0044] The above description includes exemplary embodiments according to this disclosure. These examples are provided for illustrative purposes only and are not intended to be limiting. It should be understood that this disclosure may be implemented in forms other than those expressly described and illustrated herein, and various modifications, optimizations, and variations conforming to the appended claims can be made by those skilled in the art.

Claims

1. A microelectromechanical system (MEMS) sensor, comprising: Cover plate; Base plate; A first anchor, the first anchor being coupled to the cover substrate; A plurality of second anchors, the plurality of second anchors being coupled to a base substrate; as well as A suspended spring-mass system positioned within a MEMS layer between a base substrate and a cover substrate, the suspended spring-mass system comprising: Inspect the quality block; The first anchoring portion is coupled to the cover plate via a first anchor; The second anchoring portion is coupled to the base plate via a first second anchor among the plurality of second anchors. The third anchoring portion is coupled to the base plate via a second second anchor among the plurality of second anchors, wherein the second anchoring portion and the third anchoring portion are located on opposite sides of the first anchoring portion. A first compliant spring connects the first anchoring portion to the second anchoring portion; A second compliant spring connects the first anchoring portion to the third anchoring portion; and Multiple impact-absorbing springs are coupled between the first anchoring portion and the inspection mass block.

2. The MEMS sensor of claim 1, wherein the first anchor provides mechanical anchoring only to the first anchoring portion.

3. The MEMS sensor of claim 2, wherein the connection between the first anchoring portion and the first anchor has a circular or elliptical shape.

4. The MEMS sensor of claim 1, wherein the second center point of the second anchoring portion and the third center point of the third anchoring portion are positioned equidistant from the first center point of the first anchoring portion.

5. The MEMS sensor of claim 4, wherein the second anchoring portion and the third anchoring portion have the same shape and area.

6. The MEMS sensor of claim 5, wherein the same shape is a rectangular shape or a square shape.

7. The MEMS sensor of claim 1, wherein the first compliant spring and the second compliant spring each have a lower stiffness than the plurality of shock-absorbing springs.

8. The MEMS sensor of claim 1, wherein the first compliant spring includes a first surrounding portion surrounding the second anchoring portion and the second compliant spring includes a second surrounding portion surrounding the third anchoring portion.

9. The MEMS sensor of claim 8, wherein the first compliant spring further includes a first connection connecting the second anchor portion to the first surrounding portion and a second connection connecting the first anchor portion to the first surrounding portion, and wherein the second compliant spring further includes a third connection connecting the third anchor portion to the second surrounding portion and a fourth connection connecting the first anchor portion to the second surrounding portion.

10. The MEMS sensor of claim 1, wherein each of the plurality of second anchors provides an electrical connection from the base substrate to the suspended spring-mass system.

11. The MEMS sensor of claim 10, wherein the base substrate includes a processing circuit system, wherein the electrical connection is coupled to the processing circuit system.

12. The MEMS sensor of claim 11, wherein the processing circuit system comprises a CMOS circuit system.

13. The MEMS sensor of claim 1, wherein the first anchoring portion includes a first anchored portion directly coupled to a first anchor and a first surrounding shape, the second anchoring portion includes a second anchored portion directly coupled to a first second anchor among the plurality of second anchors and a second surrounding shape, and the third anchoring portion includes a third anchored portion directly coupled to a second second anchor among the plurality of second anchors and a third surrounding shape.

14. The MEMS sensor of claim 1, wherein the plurality of shock-absorbing springs are arranged at a plurality of locations surrounding the first anchoring portion and equidistant from the first anchoring portion.

15. The MEMS sensor of claim 14, wherein each of the plurality of shock-absorbing springs is directly coupled to the first anchoring portion and extends adjacent to one of the first compliant spring or the second compliant spring.

16. The MEMS sensor of claim 15, wherein the plurality of shock-absorbing springs comprises four shock-absorbing springs, and wherein a first shock-absorbing spring extends from a first anchoring portion adjacent to a first side of a first compliant spring, a second shock-absorbing spring extends from a first anchoring portion adjacent to a second side of a first compliant spring, a third shock-absorbing spring extends from a second anchoring portion adjacent to a first side of a second compliant spring, and a fourth shock-absorbing spring extends from a second anchoring portion adjacent to a second side of a second compliant spring.

17. The MEMS sensor of claim 16, wherein the four shock-absorbing springs are arranged at 90 degrees relative to each other.

18. The MEMS sensor of claim 14, wherein the plurality of shock-absorbing springs are arranged symmetrically around the first anchoring portion.

19. The MEMS sensor of claim 14, wherein each of the plurality of impact-absorbing springs conforms to the force between the first anchoring portion and the test mass block when the MEMS sensor is subjected to an impact.

20. The MEMS sensor of claim 14, further comprising a plurality of sensing springs coupling the test mass block to the plurality of shock-absorbing springs.

21. The MEMS sensor of claim 1, wherein each of the first and second compliant springs reduces the shear force transmission between the first anchoring portion and each of the second and third anchoring portions.

22. The MEMS sensor of claim 1, wherein a first compliant spring surrounds a second anchoring portion and connects the first anchoring portion to the second anchoring portion, and a second compliant spring surrounds a third anchoring portion and connects the first anchoring portion to the third anchoring portion.

23. The MEMS sensor of claim 1, wherein the MEMS sensor includes a z-axis accelerometer, and wherein the test mass is configured to move out of plane in response to a linear acceleration force in the z-axis direction.

24. The MEMS sensor of claim 1, wherein the MEMS sensor includes an x-axis or y-axis accelerometer, and wherein the test mass is configured to move in a plane in response to a linear acceleration force in the x-axis or y-axis direction.

25. The MEMS sensor of claim 1, wherein the MEMS sensor comprises any one of a gyroscope, a pressure sensor, a magnetometer, or a microphone.

26. The MEMS sensor of claim 1, wherein at least one of the plurality of second anchors is connected to the cover substrate.

27. A microelectromechanical system (MEMS) sensor, comprising: Cover plate; Base plate; A first anchor, the first anchor being coupled to the cover substrate; A plurality of second anchors, the plurality of second anchors being coupled to a base substrate; as well as A suspended spring-mass system positioned within a MEMS layer between a base substrate and a cover substrate, the suspended spring-mass system comprising: An inspection mass block is suspended from a first anchor and a second anchor via one or more springs. The first anchoring portion is coupled to the cover plate via a first anchor; The second anchoring portion is coupled to the base plate via a first second anchor among the plurality of second anchors. The third anchoring portion is coupled to the base plate via a second second anchor among the plurality of second anchors, wherein the second anchoring portion and the third anchoring portion are located on opposite sides of the first anchoring portion. A first compliant spring of the one or more springs, the first compliant spring surrounding the second anchoring portion and connecting the first anchoring portion to the second anchoring portion; and The second compliant spring of the one or more springs surrounds the third anchoring portion and connects the first anchoring portion to the third anchoring portion.

28. A microelectromechanical system (MEMS) sensor, comprising: Cover plate; Base plate; A first anchor, the first anchor being coupled to the cover substrate; A plurality of second anchors, the plurality of second anchors being coupled to a base substrate; as well as A suspended spring-mass system positioned within a MEMS layer between a base substrate and a cover substrate, the suspended spring-mass system comprising: Inspect the quality block; The first anchoring portion is coupled to the cover plate via a first anchor; A plurality of second anchoring portions, the plurality of second anchoring portions being coupled to the base substrate via a corresponding second anchor among the plurality of second anchors; A shear reduction component, the shear reduction component being used to isolate shear forces at the first anchoring portion from the plurality of second anchoring portions; and An impact absorbing component is located between the first anchoring portion and the inspection mass block and is used to absorb the impact force at the first anchoring portion.

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