Mechanical amplified high precision, high stability angular rate sensor

Abstract

Architectures and methods of constructing high precision, high stability MEMS based angular rate sensors are provided. The structures include implementations that allow for the suppression of in-phase motion of the coupled masses, mechanical enhancement of the drive motion in the drive mass, and mechanical enhancement of the Coriolis induced motion in the sense mass. The proposed architectures minimize the mechanical momentum generated by the actuation forces in the drive, sense, and Q-compensation masses compared to the prior art. Furthermore, the methods include several implementations for achieving stress decoupling between the MEMS device and the environment and reducing anchor point damping.

Description

Technical Field

[0001] The present invention generally relates to methods of designing and manufacturing angular rate sensors (ARS). More specifically, aspects of the invention are directed to microelectromechanical systems (MEMS) vibrating gyroscopes for tactical and navigational applications. Background Technology

[0002] US 2010 / 0313657A1 and US 11,118,907B2 disclose examples of prior art devices that are very large, thus posing challenges to manufacturing and effective function. Masses and other device elements, which should be rigid, become flexible in out-of-plane directions, impairing device function. Another shortcoming of such prior art devices is the lack of complete decoupling between the drive mode and the sensing mode. Furthermore, these devices are prone to orthogonal errors caused by residual orthogonal drive motion inherent in the mechanical connections between the various masses and levers shown. For example, US 11,118,907B2 shows a U-shaped decoupled flexible element that fails to eliminate residual orthogonal movement, resulting in orthogonal errors.

[0003] US20140260615A1 describes a lever having four initially parallel rigid beams connected by flexible joints. This lever inhibits in-phase movement of vibrating elements.

[0004] WO2022248647A1 describes a dual-mass block device that partially solves the aforementioned problems. However, in the disclosed arrangement, the mechanical momentum associated with the actuation force within the drive block and the orthogonal compensation block becomes a secondary source of uncompensated orthogonal errors. Consequently, the drive actuation block and the detection block are not properly aligned.

[0005] The present invention addresses the problems of the prior art. Summary of the Invention

[0006] This invention is defined in the appended set of claims. Further aspects / embodiments / examples not included in this invention are also described.

[0007] The present invention relates to dual-mass and quad-mass tuning fork angular rate sensors, which overcome and improve upon the limitations of the prior art.

[0008] This device measures the angular velocity about the Z-axis. The device includes a substrate that defines a "reference surface" or "reference plane." The Z-axis is defined as an axis perpendicular to the reference plane. Conveniently, the reference plane is the plane of the wafer on which the MEMS structure (mass block, beam, frame, anchor point, etc.) is fabricated.

[0009] According to an independent aspect, a dual-mass microelectromechanical system (MEMS) device for measuring Z-axis angular rate is provided according to claim 1.

[0010] Advantageously, the paired mechanical amplifiers can be configured to provide linearly coupled, amplified, inverted drive-mode motion and balanced to minimize energy dissipation to the substrate, resulting in an increased drive-mode quality factor, improved stability of drive-mode motion, and improved angular random walk of the device.

[0011] Advantageously, the additional mechanical amplifier can be configured to provide linearly coupled, amplified, inverted sensing mode motion and balanced to minimize energy dissipation to the substrate, resulting in an increased sensing mode quality factor, increased rate sensitivity, increased signal-to-noise ratio, and improved angular random walk of the device.

[0012] According to a dependent aspect of the invention, a four-mass microelectromechanical system (MEMS) device is provided for measuring Z-axis angular rate. This device is implemented by mechanically connecting two dual-mass devices as defined above, to advantageously achieve better performance, improved stability, and improved suppression of vibration and linear acceleration (reduced ARW).

[0013] What will be understood is that the mass of the shuttle block is minimized without affecting its mechanical rigidity.

[0014] Suppressing the in-phase shift of the verification mass means that the out-of-phase shift is left as the fundamental resonant mode of the system, which greatly improves bias stability and ARW. In this configuration, the driving mode corresponding to the out-of-phase shift of the verification mass is the fundamental mode. The function of the driving structure is to excite and maintain the oscillation of the driving mode at a predefined, stable amplitude.

[0015] Since the stability of the drive mode amplitude is directly related to the stability of the ARS, accurate measurement of this amplitude is crucial for high-precision, high-stability devices. For a frame-based device according to the first aspect of the invention, the structure providing mechanical amplification for the drive mode motion allows for a better signal-to-noise ratio within the block controlling the drive mode amplitude. Conveniently, the same mechanical amplifier also suppresses in-phase movement of the frame, and thus suppresses in-phase movement of the verification mass block.

[0016] "Coriolis-induced movement" refers to the vibrational motion of the verification mass block generated by the Coriolis force, which is perpendicular to both the driving motion and the angular rate vector, and therefore occurs in the Y direction. "Sensing movement" refers to the movement caused by the Coriolis effect of the verification mass block and the movement of the sensing shuttle block, which can be conveniently amplified and converted back to the X direction.

[0017] Advantageously, these devices include a mechanical structure that amplifies the Y-axis movement caused by the Coriolis effect of the verification mass block into the X-axis movement of the sensing shuttle block. This amplification mechanism offers several advantages: i. It suppresses parasitic in-phase movement of the verification mass block and the sensing shuttle block, thereby highly suppressing all common-mode signals originating from the environment, such as shocks and vibrations; ii. It amplifies the mechanical Coriolis motion, thereby improving several key performance parameters of the device, such as sensitivity and ARW; iii. It reduces the sensing actuation force required to counteract the Coriolis force, thus providing a particular advantage for closed-loop operating devices; and iv. It converts Y-axis movement caused by the Coriolis effect into X-axis sensed movement, which is not possible with existing technological components (including, for example, known levers).

[0018] Point iv is a particular benefit compared to existing technology devices, because the mechanical structure provides better mechanical decoupling between sensing motion and driving motion, better vibration suppression, and better linewidth control in the DRIE process, and therefore better geometry control during manufacturing.

[0019] Advantageously, in the absence of Z-axis angular rate, the drive mode and sensing mode are decoupled from each other, so that when one mode is excited, the other mode is unaffected.

[0020] The drive shuttle block is mechanically restricted to move in the drive mode direction (X). In the subordinate aspect, the first pair of vibrating structures are mechanically connected by at least one in-phase movement suppression element. This suppression element may additionally include other elements, such as a spring that allows rotation about the Z-axis. The advantage of including at least one suppression element is that the in-phase movement of the verification mass block is suppressed, meaning that this mode is forced to move to a considerably high frequency. In contrast, in known devices (e.g., such as Sensonor SAR10, SAR100, SAR500 devices), in-phase movement is typically the fundamental mode, and therefore it is unintentionally excited and acts as a parasitic oscillation, which degrades its performance.

[0021] Preferably, the driving mode and sensing mode are parallel to the reference plane.

[0022] This device represents a tuning fork vibrating gyroscope with decoupled drive and sensing modes, combining in-plane linear motion for both modes. "In-plane" motion refers to motion occurring within or parallel to a reference plane. This contrasts with "out-of-plane" motion, which occurs outside the reference plane. In-plane linear drive and sensing motion offers numerous advantages over out-of-plane alternatives. In particular, the in-plane linear drive and sensing motion of the angular rate sensor allows for large motion amplitudes, advantageously achieving significantly higher sensitivity to Coriolis forces than out-of-plane alternatives. Furthermore, all devices using out-of-plane motion inherently suffer from out-of-plane unbalanced momentum acting on the mechanical structure.

[0023] Further dependent aspects are provided in the claims.

[0024] By mechanically connecting two such devices, an improved four-mass angular rate sensor device can be obtained. Such a device advantageously exhibits better performance than its dual-mass equivalent, with improved stability and improved suppression of vibration and linear acceleration. Attached Figure Description

[0025] The invention and accompanying examples are described in detail below with reference to the accompanying drawings, in which: Figure 1 A schematic diagram of a dual-mass angular rate sensor is shown, which includes mechanical amplifiers for both driving motion and Coriolis motion.

[0026] Figure 2 The diagram illustrates a mechanical amplifier that drives motion.

[0027] Figure 3 The diagram illustrates a mechanical amplifier for Coriolis motion.

[0028] Figure 4 The diagram illustrates the general geometry of the mechanical amplifier used.

[0029] Figure 5 A schematic diagram of a dual-mass angular rate sensor is shown, which has a mechanical amplifier for Coriolis motion.

[0030] Figure 6 A practical implementation of a dual-mass block angular rate sensor comprising a mechanical amplifier for Coriolis motion, according to an aspect of the invention, is shown.

[0031] Figure 7 A schematic diagram of a four-mass angular rate sensor is shown, which includes mechanical amplifiers for both driving motion and Coriolis motion.

[0032] Figure 8An implementation of a four-mass angular rate sensor is shown, which has mechanical amplifiers for both driving motion and Coriolis motion.

[0033] Figure 9 A schematic diagram of a four-mass angular rate sensor is shown, which has a mechanical amplifier for Coriolis motion.

[0034] Figure 10 The image depicted in the drive motion configuration is from Figure 7 A schematic diagram of the device.

[0035] Figure 11 The image depicted in the motion sensing configuration is shown from Figure 7 A schematic diagram of the device.

[0036] Figure 12 Showing the target Figure 7 The FEM simulation of the driven motion of the device shown in the figure.

[0037] Figure 13 Showing the target Figure 7 The figure shows an FEM simulation of the sensing motion of the device.

[0038] Figure 14 The image depicted in the drive motion configuration is from Figure 5 A schematic diagram of the device.

[0039] Figure 15 The image depicted in the motion sensing configuration is shown from Figure 5 A schematic diagram of the device.

[0040] Figure 16 Showing the target Figure 5 The FEM simulation of the driven motion of the device shown in the figure.

[0041] Figure 17 Showing the target Figure 5 The figure shows an FEM simulation of the sensing motion of the device.

[0042] Figure 18 An embodiment of a mechanical amplifier for Coriolis motion is shown.

[0043] Figure 19 A schematic diagram of the drive mode lever is shown.

[0044] Figure 20 An example of a movable pivot driven by a lever is shown.

[0045] Figure 21 An example of a drive lever fixed pivot is shown.

[0046] Figure 22 An example of an anchor point damping reduction structure is shown.

[0047] Figure 23 An electrical block is shown within a dual-mass block angular rate sensor that includes a mechanical amplifier for Coriolis motion.

[0048] Figure 24 An electrical block is shown within a four-mass angular rate sensor that includes mechanical amplifiers for both driving motion and Coriolis motion.

[0049] Figure 25 A preferred embodiment of a comb driver for driving and sensing mode actuation and detection is shown.

[0050] Figure 26 A preferred embodiment of a comb driver for orthogonal compensation blocks is shown.

[0051] Figure 27 A preferred embodiment of a comb driver for a frequency adjustment block is shown.

[0052] Figure 28 A C-SOI wafer is shown as a preferred starting material for manufacturing the device.

[0053] Figure 29 A general cross-sectional view of a micromachined C-SOI wafer is shown.

[0054] Figure 30 A general cross-sectional view of the completed angular rate sensor is shown. Detailed Implementation

[0055] The first embodiment of the present invention includes a dual-mass block architecture that includes mechanical amplifiers for both driving mode motion and Coriolis motion, thereby overcoming several limitations of conventional single-axis MEMS angular rate devices.

[0056] A second embodiment of the invention includes a quad-mass architecture comprising mechanical amplifiers for both driving modal motion and Coriolis motion. This is achieved by coupling two dual-mass devices according to the first embodiment to achieve complete symmetry, thereby providing complete suppression of external vibrations, shocks, and linear accelerations, and achieving a higher quality factor.

[0057] A third embodiment of the invention includes a dual-mass block architecture based on a preferred embodiment, which includes only mechanical amplifiers for Coriolis motion, representing a trade-off between size and performance.

[0058] A fourth embodiment of the invention includes a four-mass block architecture with only a mechanical amplifier for Coriolis motion. This is achieved by coupling two dual-mass block devices according to the third embodiment to achieve complete symmetry, thereby providing complete suppression of external vibrations, shocks, and linear accelerations, and achieving a higher quality factor.

[0059] Figure 1 The diagram illustrates the measurement. Z A mechanical schematic diagram of a first embodiment of a dual-mass block MEMS device (100) with axial angular rate, including mechanical amplifiers (4) and (13) for driving both motion and Coriolis motion, wherein white circles represent movable pivots and black rectangles represent anchor points.

[0060] The device (100) includes: a first pair of identical vibrating structures, namely an upper drive block 101 and a lower drive block 102, each block including a verification mass block 1, each verification mass block 1 being mechanically coupled to a drive shuttle block 2. The drive shuttle block 2 is electrostatically actuated in the drive mode direction ( X The drive mode motion of verification mass 1 is generated on the frame. The first pair of vibrating structures are elastically connected to synchronous "frames" 6 and 7 via frame connector 9, such that the drive mode corresponds to the opposite phase movement of the verification mass, while the in-phase movement of verification mass 1, drive shuttle 2, and frames 6 and 7 is suppressed. It will be understood that by means of "frame", we mean any rigid element capable of taking any suitable shape. Frames 6 and 7 are rigid and do not rotate like levers (as opposed to...). Figure 5 (The embodiment described herein is the opposite). Frames 6 and 7 are constrained to move only in directions perpendicular to the drive mode. Therefore, their movement is purely translational, in contrast to the rotational movement of the lever.

[0061] The device (100) also includes a second pair of identical vibrating structures, namely a left sensing block 103 and a right sensing block 104, each of which includes a sensing shuttle block 11. The first pair of vibrating structures and the second pair of vibrating structures are elastically interconnected by a mechanical structure 13, which verifies the Coriolis effect caused by the mass block 1. Y The amplification of the motion conversion sensing shuttle block 11 X Move towards.

[0062] Each block is suspended above the substrate by multiple sets of flexible elements, which are described later, and is then attached to the substrate via fixed anchor points 17 (also referred to as bases). This anchoring method via bases, rather than directly to the device frame, allows for the decoupling of the device's moving elements from mechanical stresses and strains caused by the environment or assembly.

[0063] The drive shuttle block 2 is primarily connected to the substrate via the main drive spring 5, to the verification mass block 1 via the Y-axis guide spring 10, and to the outer synchronization frame 6 and inner synchronization frame 7 via a mechanical amplifier formed by the rigid beam 4. The movement of the drive shuttle block 2 follows... X The shaft is constrained by the guide flexible element 3. The guide flexible element 3 is conveniently implemented as a multi-forked spring attached to the base 17.

[0064] The outer synchronization frame 6 and the inner synchronization frame 7 are interconnected by a set of structures 9, which are designed to suppress in-phase movement of the frames. Furthermore, the synchronization frames 6 and 7 are aligned along... Y The movement of the shaft is restricted by the guide flexibility 8. The guide flexibility 8 is conveniently implemented as a multi-forked spring attached to the base 17.

[0065] The sensing shuttle block 11 is primarily connected to the substrate via the main sensing spring 14, and to the verification mass block 1 via the mechanical amplifier beam 13 and the sensing mode movable pivot 15. The sensing shuttle block 11 moves along... X The movement of the shaft is restricted by the guide flexibility 12. The guide flexibility 12 is conveniently implemented as a multi-forked spring attached to the base 17.

[0066] The movable pivot 15 is constrained by the guide flexibility 16 to move only along Y Shaft movement. The guide flexible element 16 is conveniently implemented as a multi-forked spring attached to the base 17.

[0067] Beam 4, as a whole, forms a mechanical amplifier that drives the motion of the driving mode. In a similar manner, beam 13, as a whole, forms a mechanical amplifier that drives the motion of the Coriolis effect.

[0068] Figure 2 The operation of drive blocks 101 and 102 is schematically illustrated, and an amplified view of the drive mode motion is shown. When the driving force is in opposite directions... Y When the direction is applied to the outer synchronization frame 6 and the inner synchronization frame 7, they can be conveniently arranged to be in harmony with... Y The axis forms a beam 4 with a non-zero angle, forcing the shuttle block 2 along... X Directional movement. Shuttle block 2 forces verification mass block 1 to follow via beam 10. Due to the geometry of the system, as will be shown below, shuttle block 2's... X The axial displacement of 20 is greater than that of synchronous frames 6 and 7. Y Axial displacement 21.

[0069] Furthermore, the frame connector 9 connecting the synchronization frames 6 and 7 is designed to suppress in-phase movement of the frames. In a preferred embodiment of the frame connector 9, the movable pivot 18 of the frame connector 9 is constrained by a set of flexible elements tied to the base 17 to operate only when... XMovement in the direction. Synchronous frames 6 and 7 and frame connector 9 ensure the opposite phase movement of drive blocks 101 and 102.

[0070] Figure 3 A preferred embodiment of a structure for mechanically amplifying Coriolis motion is schematically illustrated. The structure includes: - Four symmetrically arranged rigid beams 13, each beam 13 and Y The axes form a non-zero angle. Each beam 13 is attached to the verification mass block 1 and the sensing shuttle block 11. The length is... L The beam is rigid under normal operating conditions, but its joints are flexible, allowing for operation under Coriolis forces (along...). Y (axis) or by sensing actuated electrostatic force (along the axis) X Change the interior angle when the axis is loaded; - A pair of main sensing spring systems 14, which restrict the connector connected to the sensing shuttle block 11 to only move along... X The movement of the axis; and - Two pairs of pivot Y-direction guide springs 16, which limit the two movable pivots 15 connected to the verification mass block 1 to move only along... Y The movement of the axis.

[0071] Due to the geometry of the spring and beam, as well as the anchoring method, the in-phase movement of the sensing shuttle block 11 and the verification mass block 1 is suppressed. In other words, the spring can be connected to a corresponding anchoring damping structure.

[0072] It will be understood that, under normal operating conditions, the movable pivot 15 is designed to allow changes in the interior angle between the rigid beams 13.

[0073] In existence along Z In the case of the angular velocity of the axis, due to the counter-driving motion of the verification mass 1, the Coriolis force will act on the verification mass in the opposite direction, thereby pushing the movable pivot 15 in the opposite direction along the Y-axis. Rigid beam 13 (which in relation to...) Y While the shaft forms a non-zero angle, the movable pivot 15 is connected to the sensing shuttle block 11, which is combined with the main sensing spring 14, forcing the shuttle block 11 to move along... X Directional movement. Due to the geometry of the system, as will be shown below, shuttle block 11's... X The axial displacement is greater than that of verification mass block 1 and movable pivot 15. Y Shaft displacement. Furthermore, the mechanical amplifier shown also suppresses the sensing of shuttle block 11 along... X In-phase movement in the direction and verification mass block 1 along Y In-phase movement in the same direction.

[0074] A key requirement for the proper functioning of the mechanical amplifier is to constrain the movable pivot 15 to move only along... YThe axis (along the axis of the Coriolis force) moves. This can be achieved by using a Y-direction guide spring 16 tethered to the base 17. The Y-direction guide spring 16 allows for movement along the axis (along the Coriolis force axis). Y It bends in the direction, but acts on... X Forces in a certain direction have a resisting elastic force.

[0075] Figure 4 The diagram illustrates a method for calculating the amplification factor of a preferred mechanical amplifier. It assumes that beam 13 remains rigid (maintaining its length). L From a geometric perspective, the minute vertical displacement y (21) of the movable pivot 15 corresponds to the amplified displacement x (20) of the sensing shuttle block 11, where θ It is the angle of rest between rigid beam 13 and the Y direction:

[0076] As a typical example, for angle θ =15°, and the magnification factor ζ=x / y =3.73 is obtained.

[0077] refer to Figure 4 What will be understood is that the balance of forces means:

[0078] Preferably, for simplicity, the mechanical amplifier 4 for driving mode motion, the mechanical amplifier 13 for Coriolis motion, and the frame connector 9 are designed in a similar manner. In a dependent aspect of the invention, these three mechanical structures can be designed and optimized independently.

[0079] Figure 5 The figure shows a mechanical schematic of a second embodiment of a dual-mass MEMS device (110) for measuring Z-axis angular rate, which includes only a mechanical amplifier (13) for Coriolis motion. Figure 5 The device includes a first pair of identical vibrating structures, namely an upper drive block 101 and a lower drive block 102, each of which includes a verification mass block 1, each verification mass block being mechanically coupled to a drive shuttle block 2. The drive shuttle block 2 generates a drive mode motion of the verification mass block 1 in the drive mode direction (X) by electrostatic actuation. The first pair of vibrating structures 101, 102 are elastically connected by a synchronizing lever 22, which is attached to the substrate by a fixed pivot 23, which allows rotation only about the Z-axis, such that the drive mode corresponds to the opposite phase movement of the verification mass block 1, while the in-phase movement of the verification mass block 1 and the drive shuttle block 2 is suppressed.

[0080] The device also includes a second pair of identical vibration structures, namely a left sensing block 103 and a right sensing block 104, each of which includes a sensing shuttle block 11.

[0081] The first pair of vibrating structures and the second pair of vibrating structures are elastically connected to each other via a mechanical structure 13, which verifies the Coriolis effect caused by mass block 1. Y The amplification of the motion conversion sensing shuttle block 11 X Move towards.

[0082] The drive shuttle 2 is connected to the synchronous lever 22 via a drive-lever movable pivot 19, which allows the drive shuttle 2 to translate along the X-axis and the lever 22 to rotate around the Z-axis.

[0083] like Figure 5 This embodiment does not use a mechanical amplifier for driving mode motion, and instead of a frame, levers are used to synchronize the drive blocks. The result may be a reduction in device performance, but the advantage is a smaller size.

[0084] Figure 6 The diagram shows... Figure 5 The actual implementation of the embodiment of the dual mass block MEMS device 110 shown.

[0085] Figure 7 A schematic diagram of a four-mass MEMS angular rate sensor 200 is shown, which includes mechanical amplifiers for driving both motion and Coriolis motion. The device is mechanically connected to two framed dual-mass devices 100 (shown in...). Figure 1 This is achieved through a combination of methods to advantageously obtain better performance, improved stability, and improved suppression of vibration and linear acceleration. Mechanical connection and synchronization are achieved through a sensing connecting beam 24 that rigidly connects to the innermost sensing shuttle block 11.

[0086] Figure 8 It shows Figure 7 The actual implementation of the four-mass block MEMS device 200 shown.

[0087] Figure 9 The diagram illustrates a four-mass MEMS angular rate sensor 210, which only has a mechanical amplifier for Coriolis motion, mechanically connected to two lever-equipped dual-mass devices 110 (shown in...). Figure 5 This is achieved by using a drive connecting spring 25 that connects the innermost drive shuttle block 2 and a sensing connecting spring 26 that connects the innermost sensing shuttle block 11, in order to advantageously obtain better performance, improved stability, and improved suppression of vibration and linear acceleration. Mechanical connection and synchronization are achieved by using a drive connecting spring 25 that connects the innermost drive shuttle block 2 and a sensing connecting spring 26 that connects the innermost sensing shuttle block 11.

[0088] Figure 10 A framed dual-mass block device 100 is shown in a drive mode configuration (shown in...). Figure 1 The mechanical schematic diagram clearly shows the counter-phase movement of the two verification mass blocks 1 and the drive shuttle block 2, the deformed main drive spring 5, the vertical displacement synchronization frames 6 and 7, and the deformed frame connector 9.

[0089] Advantageously, the Coriolis mechanical amplifier 13 and the sensing shuttle block 11 are conveniently kept undisturbed, i.e. the sensing mode and the driving mode are mechanically decoupled.

[0090] Frames 6 and 7 allow the two drive blocks 101 and 102 to synchronize. The guide flexible element 8 constrains frames 6 and 7 along... Y The movement of the axis.

[0091] The movable pivot 15 allows verification of mass block 1 along... X Linear movement of the axis without interfering with the Coriolis mechanical amplifier 13.

[0092] Figure 11 A framed dual-mass block device 100 is shown in a sensing mode configuration (shown in...). Figure 1 The mechanical schematic diagram clearly illustrates the counter-phase movement of the two verification mass blocks 1 and the sensing shuttle block 11, the deformation of the main sensing spring 14, the sensing pivot Y-direction guide spring 16 and the verification mass block Y-direction guide spring 10, and the vertical displacement pivot 15.

[0093] The drive shuttle block 2 and the synchronization frames 6 and 7 are conveniently kept undisturbed, i.e. the drive mode and the sensing mode are mechanically decoupled.

[0094] The rigid beam 13 and the main sensing spring 14 allow the two sensing blocks 103 and 104 to be synchronized.

[0095] Figure 12 It shows Figure 7 and Figure 8 The figure shows an FEM simulation of the driven motion of a four-mass block device 200 with a frame. The fixed electrodes have been removed and the deformation magnified for better visualization.

[0096] Figure 13 It shows Figure 7 and Figure 8 The figure shows an FEM simulation of the sensed motion of a four-mass block device 200 with a frame. To better visualize the deformation, the fixed electrodes have been removed and the deformation has been magnified.

[0097] Figure 14 The dual-mass device 110 with levers, depicted in a drive mode configuration, is shown (shown in...). Figure 5The mechanical schematic diagram clearly illustrates the counter-phase movement of the two verification mass blocks 1 and the drive shuttle block 2, the deformation of the main drive spring 5, and the rotation of the synchronous lever 22.

[0098] The Coriolis mechanical amplifier 13 and the sensing shuttle block 11 are conveniently kept undisturbed, i.e. the sensing mode and the driving mode are mechanically decoupled.

[0099] Lever 22 allows the two drive blocks 101 and 102 to synchronize. Fixed pivot 23 is anchored to the center of pivot 22, which allows rotation only around the Z-axis.

[0100] The movable pivot 19 allows the lever 22 to rotate without interfering with the linear movement of the drive shuttle 2 along the X-axis.

[0101] The movable pivot 15 allows the verification mass block 1 to move linearly along the X-axis without interfering with the Coriolis mechanical amplifier 13.

[0102] Figure 15 A dual-mass device 110 with levers is shown in a sensing mode configuration. Figure 5 The mechanical schematic diagram clearly illustrates the counter-phase movement of the two verification mass blocks 1 and the sensing shuttle block 11, the deformation of the main sensing spring 14, the sensing pivot Y-direction guide spring 16 and the verification mass block Y-direction guide spring 10, and the vertical displacement pivot 15.

[0103] The drive shuttle block 2 and the synchronization lever 22 are conveniently kept undisturbed, that is, the drive mode and the sensing mode are mechanically decoupled.

[0104] The rigid beam 13 and the main sensing spring 14 allow the two sensing blocks 103 and 104 to be synchronized.

[0105] Figure 16 It shows Figure 5 and Figure 6 The figure shows an FEM simulation of the driven motion of a dual-mass block device 110 with levers. The fixed electrodes have been removed and the deformation magnified for better visualization.

[0106] Figure 17 It shows Figure 5 and Figure 6 The figure shows an FEM simulation of the sensed motion of a dual-mass block device 110 with levers. To better visualize the deformation, the fixed electrodes have been removed and the deformation has been magnified.

[0107] Figure 18 A preferred design of the Coriolis mechanical amplifier 13 according to the invention is shown. Advantageously, the main drive spring 5 allows the verification mass block 1 to move along... XThe axis (drive mode direction) moves, while the movable pivot 15 is constrained by the Y-direction guide spring 16 to move only along... Y Axis movement. In the presence of a Coriolis force acting along the Y-axis, the movable pivot 15 pushes or pulls the rigid beam 13, which in turn moves along the Y-axis. X The shaft pushes or pulls the sensing shuttle block 11, while simultaneously loading the main sensing spring 14.

[0108] Main sensing spring 14 and guide flexible element 12 (see Figure 6 Together, the two sensing shuttle blocks 11 are constrained to move only along... X Shaft movement. Advantageously, springs 12, 14 and 16 are implemented as multi-forked springs anchored to base 17 to reduce stress levels and anchor point losses, thereby greatly improving the reliability and performance of the device.

[0109] For manufacturing purposes, and to accurately control the dry etching process, a filler surface 28 is inserted. The filler surface 28 is tethered to the substrate via a base 17.

[0110] Figure 19 A schematic diagram of a synchronizing lever 22 according to an alternative embodiment of the invention (devices 110 and 210 with levers) is shown. The lever 22 is anchored to the substrate via a fixed pivot 23, which only allows the fixed pivot to rotate around... Z Rotation of the axis. To decouple the rotational motion of lever 22 from the linear movement of drive shuttle block 2, drive-lever pivots 19 have been designed and implemented. These drive-lever pivots 19 significantly reduce the rotational motion of lever 22 along the axis. Y The force applied by the shaft to the drive shuttle block 2 FDy Despite the presence of a guide flexible element for driving shuttle block 3, this force can still cause orthogonal error signals. Note that the implementation illustrated here is based on a similar design submitted separately by the same author.

[0111] Figure 20 A preferred design of the drive-lever pivot 19 and the guide flexibility for driving the shuttle block 3 is shown in an alternative embodiment of the invention (devices 110 and 210 with levers).

[0112] Figure 21 A preferred design for the lever-fixed pivot 23 according to an alternative embodiment of the invention (devices 110 and 210 with levers) is shown. A set of at least four, but preferably six, “S”-shaped springs 27 (one end of which is attached to the substrate) allows the lever 22 to rotate around... Z The axis rotates, while all translation is suppressed. A damper 28, designed as a flexible cantilever with a stop, is added to limit the rotation of the lever to its maximum value, thereby protecting the device from large external mechanical shocks.

[0113] Applicable to all embodiments described herein, Figure 13 An innovative anchor point damping reduction structure 30 according to an embodiment of the present invention is shown. Instead of directly connecting the movable universal spring 29 to its corresponding anchor point 17, a set of lateral restraint beams 31 is introduced to move the clamping / fixing surface of the universal spring 29 away from the anchor point 17, thereby reducing the energy transferred away through the bottom side of the anchor point surface. Furthermore, a set of beams 32 is used to reduce the direct attachment area between the universal spring 29 and the anchor point 17, thereby further reducing anchor point-related losses.

[0114] Figure 23 and Figure 24 The positions of various electrical blocks within the lever-equipped dual-mass block device 110 and the frame-equipped quadruple-mass block device 200 are shown respectively.

[0115] Each drive shuttle block 2 includes a drive actuator block 501 and a drive detection block 502, wherein the former is used to electrostatically drive the first pair of vibrating structures (fork teeth 101 and 102) into anti-phase oscillation, while the latter is used to measure / quantify the amplitude of the oscillation.

[0116] For the four-mass block device 200 with a frame, the drive actuator block 501 is located on the external synchronization frame 6, while the drive detection block 502 is conveniently located on the drive shuttle block 2.

[0117] For the framed dual-mass block device 110, the drive actuation block 501 and the drive detection block 502 are both located on the drive shuttle block 2 and aligned along the central horizontal axis of the verification mass block 1. In an alternative embodiment of the invention, the drive actuation block and the drive detection block can be combined into a single block, which will operate in a time-multiplexed mode, acting as an electrostatic actuator most of the time and as a capacitive amplitude detector part of the time.

[0118] Compared to existing technologies, these specific arrangements do not introduce unwanted mechanical momentum associated with drive mode motion.

[0119] Each sensing shuttle block 11 includes a sensing actuator block 503 and a sensing detection block 504, wherein the former is used for electrostatic cancellation / balancing of the movement of sensing vibration structures 103 and 104, while the latter is used for measuring / quantifying the amplitude of residual oscillations. In an alternative embodiment of the invention, the sensing actuator block and the sensing detection block can be combined into a single block, which will operate in a time-multiplexed mode, acting as an electrostatic actuator most of the time and as a capacitive amplitude detector part of the time.

[0120] In addition, each of the verification quality blocks 1 contains a pair of orthogonal error compensation blocks 505, which can perform electrostatic compensation for orthogonal errors.

[0121] Furthermore, for devices operating in a pattern-matching manner, each sensing shuttle block 11 includes at least one frequency adjustment block 506, which can adjust the electrostatic damping until the sensing mode frequency matches the driving mode frequency.

[0122] As mentioned earlier, and regardless of the actual implementation, these devices employ electrostatic actuation and capacitive sensing to generate and detect the movement of various components. Figure 25 A preferred embodiment of a comb driver 35 for driving and sensing mode actuation and detection is shown. It consists of a fixed electrode 33 (anchored to the substrate via a base 17) and a movable electrode 34 (attached to the drive shuttle block and the sensing shuttle block).

[0123] like Figure 25 The illustration shows a preferred area closure scheme, wherein the common area between the comb fingers changes during movement. In an alternative embodiment of the invention, a gap closure scheme can be used, wherein the gap between the comb fingers changes.

[0124] This device can employ an electrostatic orthogonal compensation block 505, such as Figure 26 As illustrated, block 505 includes a set of comb drivers 35, each comb driver having a fixed electrode 33 (anchored to the substrate via base 17) and a movable electrode 34 (attached to verification quality block 1). Within the design's operating range, block 505 eliminates any residual orthogonality errors that may still exist.

[0125] The device also employs a frequency adjustment block 506, such as Figure 27 As illustrated, block 506 consists of a set of combs 35, each comb having a fixed electrode 33 (anchored to the substrate via base 17) and a movable electrode 34 (attached to sensing shuttle block 11). Block 506 electrostatically dampens sensing mode movement in a controlled manner, thereby adjusting its resonant frequency downward in order to match the driving mode frequency for mode-matching operation.

[0126] consider Figure 28 Regardless of the embodiment chosen, the preferred starting material for fabricating the device is a cavity SOI (C-SOI) wafer 300, which comprises a substrate or handle wafer 301, a device layer 302, an insulating buried oxide (BOX) layer 303, a back oxide layer 304 for controlling wafer bowing and warping, and a sealed cavity 305 implemented in the substrate. The buried oxide layer 303 may be completely absent from the cavity, as illustrated, or may be present on the device layer or the substrate, or both.

[0127] Figure 29A general cross-sectional view of the micromachined C-SOI wafer is shown. A selected front-side metal layer 306 has been deposited and patterned to form one side of the electrical contacts and sealing ring. A selected back-side metal layer 307 has been deposited and optionally patterned to form electrical contacts to the substrate. DRIEs are used to pattern the device layers in a region located inside the cavity to define DRIE trenches 308, mechanical structures 311 (combs, fingers, springs, verification mass blocks, shuttle blocks, levers, etc.), anchor points 310, and die frames 309.

[0128] Figure 30 The overall cross-sectional view of the completed angular rate device is shown, which is in Figure 29 This is achieved after wafer-level bonding between the MEMS wafer 300 and the overlay wafer 400 containing electrical wiring. At least one front-side oxide layer 401 is used to provide insulation between various conductive elements. At least one selected front-side metal layer 402 has been deposited and patterned to form the second side of the electrical contacts and sealing ring, and to ensure the necessary wiring for signals from the electrodes located on the MEMS wafer 300 to the device pads 403 located on the overlay wafer 400.

[0129] Figure label description 100 Framed 2-mass MEMS ARS Structure 110 Two-mass MEMS ARS structure with levers 200 Framed 4-mass MEMS ARS Structure 210 4-mass MEMS ARS structure with levers 300 C-SOI chip 400 Covered Silicon Wafer 1. Verify the quality block 2 Drive shuttle block 3. Guide flexible component for driving shuttle block 4. Drive amplifier beam 5. Main drive spring 6. External Synchronization Framework 7. Internal Synchronization Framework 8. Guided flexible element for synchronization frame 9. Inverting frame connector 10. Verify the Y-axis guide spring of the mass block. 11 Sensing Shuttle Block 12 Guide flexible element for sensing shuttle block 13 Sensing Amplifier Beam 14 Main sensing spring 15-sensing mode movable pivot 16 Pivot Y-direction guide spring 17 Anchor Points 18 Frame Connector Pivot 19 Drive-Lever Pivot 20. Magnified displacement X 21 Source displacement Y 22 Synchronous Lever 23. Lever fixed pivot 24 Sensing Connecting Beams 25 Drive connection spring 26 Sensing connection spring 27 Fixed pivot spring 28 Fixed pivot shock absorber 29 General-purpose beams 30 Anchor point damping reduction structure 31 Lateral restraint beam 32 Beams with reduced anchorage area 33 Fixed Electrode (Stator) 34 movable electrodes 35 Drive / Sensing Comb Driver 36 Q-compensation comb 37 F-Adjusting Comb 38 Filled Surface 101 Upper-driven vibration structure 102 Lower driven vibration structure 103 Left sensing vibration structure 104 Right sensing vibration structure 300 C-SOI chip 301 C-SOI processed wafer (substrate) 302 C-SOI device layer 303 Buried Oxides 304 Backside Oxide 305 cavity 306 Front Metal 307 Backside Metal 308 DRIE Groove 309 Chip Frame 310 Anchor Point / Base 311 Mechanical Structure 312 Reference Plane 400 Covered Silicon Wafer 401 Insulating Oxides 402 metal layers 1 and 2 403 pad 501 Drive Actuator Block 502 Driver Detection Block 503 Sensor Actuator Block 504 Sensor Detection Block 505 Q-Compensation Block 506 F-Adjusting Block

Claims

1. A dual-mass mechanical amplification microelectromechanical sensor (MEMS) device for measuring Z-axis angular velocity, the sensor comprising: A substrate that defines a reference plane, wherein the Z-axis is perpendicular to the reference plane, and an XY plane is defined by the reference plane, the XY plane including an X-axis and a Y-axis orthogonal to each other; A first pair of vibrating structures (101, 102) are connected by a rigid frame (6, 7) for structurally providing anti-phase movement of the vibrating structures at a first predetermined frequency, at which in-phase movement of the first pair of vibrating structures is suppressed and the vibrating structures are synchronized, wherein the rigid frame (6, 7) is configured to move perpendicular to the direction of the drive mode movement. The second pair of vibrating structures (103, 104) is configured as a sensing mode mechanism to provide a balanced antiphase shift toward a second predetermined frequency in the direction of sensing mode motion, wherein in-phase shift of the second pair of vibrating structures is suppressed in the direction of sensing mode motion. A pair of mechanical amplification structures (4), which elastically connect the first pair of vibrating structures to the rigid frame (6, 7) for amplifying the movement of the first pair of vibrating structures in the direction of the driving mode motion relative to the rigid frame; and An additional mechanical amplification structure (13) elastically connects the first pair of vibrating structures and the second pair of vibrating structures to amplify the movement caused by the Coriolis effect. The direction of motion in the sensing mode is parallel to the direction of motion in the driving mode.

2. The device of claim 1, wherein, The first pair of vibration structures includes a first verification mass block and a second verification mass block, each verification mass block being mechanically connected to a first drive shuttle block and a second drive shuttle block, the drive shuttle block being used to generate drive mode movement of the verification mass block in the direction of the drive mode movement.

3. The device of claim 1 or 2, wherein, The second pair of vibration structures includes a first sensing shuttle block and a second sensing shuttle block.

4. The device of claim 2, wherein, The first drive shuttle block and the second drive shuttle block are mechanically constrained by a flexible element to move only in the direction of the drive mode movement.

5. The device according to claim 3, wherein, The first sensing shuttle block and the second sensing shuttle block are mechanically constrained by a flexible member to move only in the direction of the sensing mode movement.

6. The device of claim 2, wherein, The additional mechanical amplification structure includes four symmetrically arranged rigid beams, each forming a non-zero angle with the direction of motion caused by the Coriolis effect of the first and second verification mass blocks.

7. The device of claim 6, wherein, The rigid beams are connected to the surrounding blocks via flexible joints or pivots to change the interior angles between the rigid beams, thereby amplifying the movement along the X-axis relative to the movement along the Y-axis.

8. The device of claim 2 or 6, wherein, The additional mechanical amplification structure includes a pivot connected to the first verification mass block, the second verification mass block, and the anchor point via a first spring system.

9. The device of claim 3, wherein, The additional mechanical amplification structure includes a pivot connected to the first sensing shuttle block, the second sensing shuttle block, and the anchor point via a second spring system.

10. The device of claim 1, wherein, The first pair of vibrating structures includes a first plurality of electrodes for driving movement actuation and a second plurality of electrodes for driving movement amplitude detection.

11. The device of claim 10, wherein, The first pair of vibrating structures includes multiple electrodes configured to achieve both actuation of the driven movement and detection of the driven movement amplitude via time multiplexing.

12. The device of claim 1, wherein, The second pair of vibrating structures includes a first plurality of electrodes for sensing motion actuation and a second plurality of electrodes for sensing motion amplitude detection.

13. The device of claim 12, wherein, The second pair of vibrating structures includes multiple electrodes configured to achieve both the sensing motion actuation and the sensing motion amplitude detection via time multiplexing.

14. The device of claim 8, wherein, Both the first verification mass block and the second verification mass block include multiple electrodes configured to compensate for residual orthogonality errors.

15. The device of claim 9, wherein, The first sensing shuttle block and the second sensing shuttle block include a plurality of electrodes configured to electrostatically down-adjust the sensing frequency until it matches the driving frequency.

16. The device according to claim 1, further comprising an anchor point damping reduction structure.

17. The device of claim 16, wherein, The anchor point damping reduction structure includes multiple lateral constraint beams for blocking the lateral vibration of the spring and for reflecting sound waves associated with the vibrational movement of the spring.

18. The device of claim 17, wherein, The anchor point damping reduction structure also includes at least one anchorage area reduction beam.

19. An angular rate MEMS device system, the angular rate MEMS device system comprising two mechanically coupled devices according to any one of the preceding claims.

20. A method of manufacturing a device according to any one of claims 1-18, the method using a CSOI wafer and comprising performing a DRIE process within the device layer of the CSOI wafer.

21. The method of claim 20, wherein, The method also includes wafer-level bonding of the CSOI wafer, wherein electrical wiring covering the silicon wafer includes signal and device pads.

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