CN104272062B - Z-axis electrode structure of microelectromechanical system (MEMS) multi-axis gyroscope - Google Patents

Abstract

Various examples are disclosed, including a microelectromechanical die for sensing motion that includes symmetrical proof-mass electrodes interdigitated with asymmetrical stator electrodes. Some of these examples include electrodes that are curved about an axis orthogonal to the plane in which the electrodes are disposed. One example provides vertical flexures that couple the inner gimbal to the proof mass in a manner that allows flexure about a horizontal axis.

Description

Z-axis electrode structure of microelectromechanical system (MEMS) multi-axis gyroscope

claim priority

This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 61/593,691, filed February 1, 2012, entitled "MEMSMULTI-AXISGYROSCOPE WITH CENTRALSUSPENSIONANDGIMBALSTRUCTURE" (MEMS Multi-Axis Gyroscope with Central Suspension and Ring Frame Structure) , which is incorporated herein by reference in its entirety.

Background technique

Quadrature error is one of the main factors limiting the performance of micromechanical sensors such as gyroscopes. Given the relative magnitudes of the driven and induced oscillations, even a tiny fraction of the driven motion coupled into the induced mode may dominate the Coriolis response.

In fact, manufacturing imperfections can lead to suboptimal geometries in structures such as gyroscope structures. Suboptimal geometries may cause driven oscillations to partially couple into the inductive mode. Even though there are several cross-coupling pathways such as elastic, viscous and electrostatic coupling pathways, in some cases elastic coupling increases beyond the required criteria due to anisoelasticity in the suspension elements.

In sensor systems with an out-of-plane mode of operation, such as gyroscope systems, the anisotropy between in-plane and out-of-plane directions is a major source of quadrature error. Skew or tilt in deep reactive ion etching ("DRIE") can cause the cross-section of the flexure bearing to deviate from a rectangle to a parallelogram, which in turn causes the principal elastic axis of the suspended flexure bearing to deviate from being parallel to the device surface ( direction), or deviate from normal to the device surface (direction). In one example, single-axis or multi-axis micromachined sensor structures such as gyroscope structures can suffer from high quadrature errors caused at least in part by DRIE tilt.

In addition, existing resonators rely on simple linear flexure bearings to create a flexure structure that allows the device to shift in resonance. Etching can cause major problems when it creates tilt in the flexure bearing, causing large undesired displacements and often actuating the sensing mechanism.

Description of drawings

In the drawings (which are not necessarily drawn to scale), like numerals may describe similar parts in the different views. The same number with different letter suffixes can represent different instances of similar components. The drawings generally illustrate, by way of illustration and not limitation, various embodiments discussed in this application.

Fig. 1 shows a sensor structure including a suspension structure according to an example.

Figure 2A shows a portion of a suspension according to one example.

FIG. 2B shows the suspension of FIG. 8A in an example in a bent state in which the top portion is bent upward.

FIG. 2C shows the suspension of FIG. 8A in an example in a bent state in which the top portion is bent downward.

Fig. 3 shows the torsional movement about the Z-axis of the suspension structure according to an example.

Fig. 4 shows the torsional movement about the X-axis of the suspension structure according to an example.

Fig. 5 shows the torsional movement about the Y-axis of the suspension structure according to an example.

Figure 6 shows a 2-axis gyroscope including a low quadrature error suspension, according to an example.

FIG. 7 shows a 3-axis gyroscope including a low quadrature error suspension, according to an example.

Figure 8 shows the quadrature error for an exemplary suspension.

Fig. 9 shows driving modes according to one example.

Figure 10 shows a flexure bearing with four bends, according to one example.

11 illustrates a flexure bearing including a flexure flexure and a non-flexure flexure according to one example.

12 illustrates a flexure bearing comprising a flexure and a non-flexure flexure, the flexure being shorter than the flexure of FIG. 11 , according to one example, The non-flexing flex bearing is shorter than the non-flexing flex bearing of FIG. 11 .

Figure 13A shows a suspension with a large gap, according to one example.

Figure 13B shows the stresses associated with the degree of deflection of the flexure bearing.

Figure 14A shows a suspension including a zigzag according to one example.

Fig. 14B shows a section taken at 14B of Fig. 14A.

Fig. 14C shows a section taken at 14C of Fig. 14A.

Fig. 14D shows a cross section taken at 14D of Fig. 14A.

15 illustrates the suspension of FIG. 14 torsionally flexed about the Z-axis, according to one example.

16A shows the suspension of FIG. 14 torsionally flexed about the Z-axis, according to one example.

16B shows the suspension of FIG. 14 flexed about the Y-axis, according to one example.

16C shows the suspension of FIG. 14 flexed about the X-axis, according to one example.

FIG. 16D shows the suspension of FIG. 14 displaced and deflected along the Y-axis, according to one example.

Figure 17 illustrates a method of making a low quadrature error suspension, according to one embodiment.

Figure 18 illustrates a method of making a vibration-suppressing z-axis electrode, according to one embodiment.

detailed description

Undesirable sidewall deflection can be damaging to flexure bearings ("flexures"), such as flexure bearings, that support one or more portions of a microelectromechanical systems ("MEMS") structure (such as a die). Performance is negatively affected. In one example, in-plane driving motion can cause out-of-plane motion if one or more sidewalls have an angular error, such as when the tilt axis is along the length of a flexure bearing or beam. In one example, when a slanted pliable or compliant flexure bearing or beam is on the opposite side during drive motion, the resulting out-of-plane deflection can cause or add to quadrature error. In one example, a low-orthogonal suspension system is designed to reduce or counteract undesired out-of-plane motion.

Fig. 1 shows a sensor structure including a suspension structure according to an example. Various examples disclose low orthogonal suspension systems for sensors. In one example, the suspension structure may be used in a torsion multi-axis micromachined gyroscope system with a proof-mass, such as single-mass 104 . In one example, the mass 104 is suspended at its center by a single central anchor 106 . In one example, one or more flexure bearings connect the anchor 106 to the proof-mass 104 , such as to the main frame 116 of the proof-mass. In one example, the one or more flexures allow the mass to torsionally oscillate about three perpendicular axes. In one example, suspended flexure bearings or beams provide in-plane and out-of-plane deflections, allowing the mass to oscillate torsionally about the x-, y-, and z-axes.

One example includes a fixed portion 118 where the anchor 106 is coupled to the fixed portion 118 . In one example, the first nonlinear suspension member 108 is coupled to the anchor on one side of the anchor 106 . In one example, a second nonlinear suspension member 120 is coupled to the anchor on the same side of the anchor, the second nonlinear suspension member having a bisecting plane 122 ( Such as x-z plane) shape and position in a mirror image relationship. Various examples include a planar proof-mass 104 suspended at least in part by a first nonlinear suspension member 108 and a second nonlinear suspension member 120 such that the proof-mass is rotatable about an anchor 106 and can rotate parallel to a fixed sliding in a partial plane, such as in the x-y plane.

In one example, the C-shaped flexure bearing 108 includes an inner portion 110 coupled to the anchor 106 and extending toward the anchor bisecting surface 122, a central portion 114 having a proximal portion and a distal portion, wherein the proximal portion is coupled To inner portion 110 , a distal portion extends away from anchor 106 along anchor bisecting plane 122 and is coupled to outer portion 112 extending away from anchor bisecting plane 122 . In one example, central portion 114 is perpendicular to inner portion 110 and outer portion 112 . In one example, central portion 114 is parallel to anchor bisecting plane 122 .

In one example, anchor 106, first nonlinear suspension member 108, second nonlinear suspension member 120, and proof-mass 104 are formed from a single piece of material. In one example, fixed portion 118 includes a fixed monolithic piece of material that is different from the monolithic material of anchor 106 , first nonlinear suspension member 108 , second nonlinear suspension member 120 , and proof-mass 104 . In one example, fixed portion 118 includes the same fixed piece of material as the single piece of material of anchor 106 , first nonlinear suspension member 108 , second nonlinear suspension member 120 , and proof-mass 104 .

In one example, flexure bearings are provided on each side of a central anchor, such as on opposite sides of the anchor. In one example, the out-of-plane motion induced by each C-shaped flexure bearing on one side is counteracted by its symmetrical flexure bearing. Thus, in one example, quadrature errors induced on each flexure bearing are locally reduced or cancelled.

In one example, the central suspension structure 102 is used in a sensor, such as a 6-degree-of-freedom ("DOF") sensor 100 (such as a monolithic 6-DOF sensor composed of symmetrical flexure bearings). In one example, the symmetrical flexure bearing includes a “C-shaped flexure bearing” 108 . In one example, each C-shaped flexure bearing includes an inner flexure bearing 110 and an outer flexure bearing 112 with a high stiffness connecting flexure bearing 114 between the two flexure bearings. In one example, the inner flexure bearing 112 is connected to the anchor 106 at one end and the outer flexure bearing 112 is connected to the mass 104 at the other end. In one example, the suspension system 102 is formed from a total of eight C-shaped flexure bearings 108 . In one example, two symmetrical C-shaped flexure bearings are located on each of the four sides of the central anchor structure.

In one example, the suspension provides three modes of gyroscope operation: in-plane twist around the Z axis for driving motion; out-of-plane twist around the X axis for Y-axis gyroscope-sensed motion; and around the Y-axis The out-of-plane twist for the X-axis gyroscope to sense motion. In one example, the oscillation modes can be switched between each other.

Figure 2A shows a portion of a suspension according to one example. FIG. 2B shows the suspension of FIG. 2A in an example in a bent state in which the top portion is bent upward. FIG. 2C shows the suspension of FIG. 2A in an example in a bent state in which the top portion is bent downward. The example shown shows the deformation profile in all directions of the suspension mechanism. In one example, bending occurs equally and oppositely in the two deformation cases shown in Figures 2B and 2C. In one example, in each direction, the two flexure bearings bend in opposite ways. In one example, the overall out-of-plane deformation from one end of the flexure to the other is minimized by creating opposing out-of-plane deformations that cancel each other out.

Fig. 3 shows the torsional movement about the Z-axis of the suspension structure according to an example. In one example, the suspension system 300 includes two symmetrical C-shaped flexure bearings 302 , 304 on each side of a central anchor structure 306 . In one example, one or both of the C-shaped flexure bearings 302 , 304 are formed by a high stiffness connecting flexure bearing 308 disposed between the two flexure bearings 310 , 312 . In one example, during in-plane torsional motion (such as motion parallel to the plane of the figure), the out-of-plane motion caused by the deflection of the flexure bearings in each C-shaped flexure bearing on one side is symmetric The flex bearings 310', 312' are offset. Thus, quadrature errors induced on each flexure bearing are locally reduced or cancelled.

The example shown shows twisting motion about the Z-axis (ie, the axis extending into the page and out of the page). In one example, the inner flexure bearing 310 and the outer flexure bearing 312 in each C-shaped flexure bearing bend in-plane during in-plane torsional motion. In one example, high stiffness connection support 308 does not experience significant bending. For a counterclockwise rotation of the proof-mass about the Z-axis, the top portion of the proof-mass moves to the left as shown. In one example, the high stiffness link supports are all shifted to the left. Thus, the inner and outer flexures of the right C-shaped flexure bearing are bent downward, while the inner and outer flexures of the left C-shaped flexure bearing are bent upward. Thus, in one example, the movement causes deflection of the flexures of the symmetrical C-shaped flexure bearing in opposite directions. Due to the deflection of the flexures in opposite directions in the symmetrical C-shaped flexure bearings, the out-of-plane motion caused by the deflection of the flexure bearings in each C-shaped flexure bearing on one side is symmetrical by its The deflection bearing part offsets. Thus, the quadrature error induced on each flexure bearing is locally cancelled.

Fig. 4 shows the torsional movement about the X-axis of the suspension structure according to an example. In one example, the suspension structure may be used in a torsion multi-axis micromachined gyroscope system with a mass, such as single mass 404 . In one example, the mass 404 is suspended at its center by a single central anchor 406 . In one example, one or more flexure bearings 402 connect anchor 406 to proof-mass 404 . In one example, during out-of-plane torsional motion about the X-axis, it is primarily the Y-axis side C-suspension pair 412, 412' that deflects. In one example, the inner flexure bearings 410, 410' in these C-suspension members are torsionally bent about the X-axis, acting as torsional hinges.

In one example, the die is wafer shaped and the first nonlinear suspension member 408 and the second nonlinear suspension member 412 each have a generally rectangular cross-section with a height smaller than a width.

Fig. 5 shows the torsional movement about the Y-axis of the suspension structure according to an example. In one example, the suspension structure may be used in a torsion multi-axis micromachined gyroscope system with a mass, such as single mass 404 . In one example, the mass 404 is suspended at its center by a single central anchor 406 . In one example, one or more flexure bearings 402 connect anchor 406 to proof-mass 404 . In one example, during out-of-plane torsional motion about the Y-axis, it is primarily the X-axis side C-suspension pair 412, 412' that deflects. The inner flexure bearing of these C-shaped flexure bearings 414, 414' is torsionally bent about the Y-axis, acting as a torsion hinge.

Figure 6 shows a 2-axis gyroscope including a low quadrature error suspension, according to an example. In one example, structure 602 may be used in various torsional multi-axis micromachined gyroscope systems having a single mass 604 at its center via a single central anchor 606 suspension. Flexures 608 connect the anchors to the mass 604 and allow the mass to torsionally oscillate about all three axes. The example shown detects motion about each of the X and Y axes and demonstrates three gyroscope modes of operation: in-plane twist about the Z axis for driving motion, and out-of-plane twist about the X axis for a Y-axis gyro gyroscope-induced motion; and out-of-plane twist around the Y-axis for X-axis gyroscope-induced motion. In one example, one or more comb electrodes 616 are coupled to a fixed portion of the device and are inductively coupled to the movement of comb electrodes 618 of proof mass 604 . In one example, the comb teeth of the comb electrode 618 are arranged along an axis that bisects the angle between the X axis and the X axis.

FIG. 7 shows a 3-axis gyroscope including a low quadrature error suspension, according to an example. In one example, structure 702 may be used in various torsional multi-axis micromachined gyroscope systems having a single mass 704 at its center via a single central anchor 706 suspension. A flexure 708 connects the anchor to the mass 704 and allows the mass to torsionally oscillate about all three axes. In one example, the device functions as a three-axis ("X/Y/Z") gyroscope. In one example, the suspension system 702 provides a gyroscope mode of operation similar to that shown in FIG. 6 . In one example, the device shown in FIG. 7 includes an additional flexure 720 provided for the Z-axis sensing mode. In one example, one or more comb electrodes 716 are coupled to a fixed portion of the device and are inductively coupled to the movement of comb electrodes 718 of proof mass 704 . In one example, the comb teeth of the comb electrode 718 are arranged along an axis that bisects the angle between the X axis and the X axis.

Figure 8 shows the quadrature error for an exemplary suspension. In one example, the angle of the flexure bearing has a significant effect on orthogonality. In one example, for each design, the angle can be chosen to optimize the quadrature error produced by the tilt of the flexure of the resonator flexure bearing. In one example, the optimal angle for the desired suspension system implementation is 15 degrees. In one example, the optimal angle depends on the shape of the structure and is selected based on the structure of the corresponding device. In one example, the two flexure bearings are arranged at the same angular displacement for the desired configuration, but the two flexure bearings could easily be arranged at different angles.

Fig. 9 shows driving modes according to one example. The inventors have realized that in a suspension configuration including anchor 906, the effects of tilt cause quadrature errors and that they can minimize this effect by creating opposite tilts on the same flexure 902 or pair of flexures 904 . Accordingly, there are two flexing flexure bearings separated by the frame, each flexure bearing being deformed in opposite directions in the driving mode of operation. Deformations in opposite directions result in tilts that produce opposite out-of-plane deformations that cancel each other out at the eventual connection to the moving part. This can be used to replace existing mechanisms that include only one flexure bearing, the tilting of which produces deformation in only one direction, causing a large amount of out-of-plane motion without any cancellation.

However, in some examples, the inner flexure bearings 910, 910' and outer flexure bearings 912, 912' rotate such that during drive mode actuation, deformation causes one flexure bearing to bend upward and one flexure bearing downward . In one example, the drive pattern is a rotational pattern about a central anchor. In one example, for each of the four suspension pairs 404, the drive pattern is such that one deforms in one direction and the other deforms in the other direction.

Figure 10 shows a flexure bearing with four bends, according to one example. In one example, flexure 1002 may include more than one bend. In one example, this may allow for more tightly controlled out-of-plane motion. In one example, a plurality of zigzags 1004 are included. In one example, the zigzag defines a zigzag extending from anchor 1006 to proof proof 1005 . In one example, the zigzag line includes zigzags of regular magnitude along a pattern extending from anchor 1006 to proof proof 1005 . In other embodiments, the amplitude varies. In one example, the zigzag portion is C-shaped with top member 1008 and bottom member 1014 parallel to each other but non-parallel to high stiffness portion 1016 .

11 illustrates a flexure bearing including a flexure flexure and a non-flexure flexure according to one example. In one example, the parameters of the flexure 1102 may also be determined by lengthening or shortening the flexure bearings 1110 , 1114 or the non-flexure flexure bearing 1112 . In the example shown in FIG. 12, the outer flexure flexure bearing 1110 and the non-flexure flexure bearing 1112 are shortened.

12 illustrates a flexure bearing comprising a flexure and a non-flexure flexure, the flexure being shorter than the flexure of FIG. 11 , according to one example, The non-flexing flex bearing is shorter than the non-flexing flex bearing of FIG. 11 . The outer deflected flexure bearing 1210 and the non-flexure flexure bearing 1212 are shortened compared to the components of FIG. 11 .

Figure 13A shows a suspension with a large gap, according to one example. Figure 13B shows the stresses associated with the degree of deflection of the flexure bearing. In an example, a gap 1302 is provided between the flexure bearing 1304 and the mass 1306 .

14A-D illustrate a die 1400 including various features, according to one example. These features can be used alone or in combination. One feature is the zigzag 1402 . Zigzag 1402 extends between a nonlinear suspension member (eg, C-shaped flexure bearing 1406 ) and proof-mass 1408 . Adding zigzags 1402 can further reduce quadrature error at least because it reduces out-of-plane deflection that is at least partially caused by DRIE etching. Like counteracting the bending of one support by bending the other support across one side of a plane such as plane 1422 . The out-of-plane bending may be counteracted by bending the second flexure bearing 1407 , which may be disposed on the other side of the plane 1423 .

Such cancellation is shown in FIG. 15 . In Fig. 15, the first support portion 1502 is bent away from the mass 1508, while the support portion disposed on the other side of the horizontal reference plane 1510 is bent towards the mass. The support 1506 on the other side of the vertical reference plane 1512 and on the other side of the horizontal reference plane 1510 also bends away from the mass 1508 in substantially the same way as 1506, which restores the balance of the suspension by flexing the support. to offset the quadrature error.

14A and the description of the zigzag 1402, the nonlinear suspension member 1406 (e.g., a C-shaped flexure bearing) includes a first or inner portion 1410, a second or central portion 1420, and a third or outer portion 1412. In one example, outer portion 1412 has a proximal portion coupled to central portion 1420 . In one example, a distal portion of outer portion 1412 extends away from anchor bisecting plane 1422 . In one example, the outer portion 1412 is coupled with the fourth portion 1402 (eg, a portion of the zigzag) of the first nonlinear suspension member 1406 . In one example, fourth portion 1402 is coupled to a distal portion of outer portion 1412 at a proximal portion of fourth portion 1402 . In one example, fourth portion 1402 extends from a proximal portion thereof toward anchor 1404 to a distal portion thereof. In one example, a distal portion of fourth portion 1402 is coupled to fifth portion 1424 of first nonlinear suspension member 1406 . In one example, fifth portion 1424 extends toward anchor bisecting plane 1422 . In one example, inner portion 1410 and outer portion 1412 are linear and parallel. Overall, the zigzag 1402 example provides additional flex, and counteracts that flex, relative to a suspension that does not have the zigzag 1402 .

The second feature is the asymmetric stator finger electrodes, as particularly exemplified in Figures 14C-D. The electrode structures partially illustrated in Figures 14C and 14D are configured for use in a MEMS multi-axis gyroscope with an inverse linear Z-axis rotation sensing mode. In some examples, the two masses 1454 and 1456 can move in opposite directions. An example of such motion is illustrated in Figure 16D. In one example, the stators 1430, 1431 are anchored by respective side anchors 1428, 1429. In various examples, the electrodes on opposite sides of the central anchor 1404 should be sensitive to concurrent outward or inward motion of the proof-mass to enable differential pickup of that motion. Therefore, stator poles that are symmetrical about the Y-Z axis should not be used because this design will not sense differential motion, and because differential motion sensing relies on providing a capacitive difference between the two sides of the device, and if the stator poles are symmetrical, The capacitance will then vary similarly on both sides of the Y-Z axis.

The Z-axis rotating sensing electrode structure shown senses differential motion. This configuration provides differential detection of anti-phase induced motion where the proof-mass fingers are symmetric about the Y-Z plane 1422 and the stator electrodes are not. A symmetrical electrode configuration is required for vibration suppression. The disclosed electrodes provide a symmetrical proof-mass electrode across the Y-Z plane. The symmetrical proof-mass electrodes achieve improved vibration suppression relative to asymmetrical designs.

14C-D are cross-sectional views showing staggered bonding details on opposite sides of a die according to one example. Although the electrodes are pixelated in appearance, smoothly continuous electrodes, such as those exhibiting the characteristics of DRIE, are conceivable. In FIG. 14C , left stator 1430 has stator fingers 1450 outside (eg, further away from center anchor 1404 ) of proof-mass 1446 fingers 1452 , while right stator 1430 ′ is shown in FIG. The stator fingers 1452' inside the 'fingers 1452'. It should be noted that in both electrodes of Figures 14C and 14D, the small capacitive gap is located to the left of the stator fingers, and the proof-mass fingers are completely symmetrical. As the proof-mass 1454 of Figure 14C moves to the left, the capacitance of the electrodes in this figure increases. As the proof-mass 1456 of Figure 14D moves to the right, the capacitance of the electrodes in this figure decreases. Thus, a detectable differential capacitance is created.

In one example, Z-axis gyro sensed motion is sensed via differential mass sensing, while in-phase motion (ie, motion of the masses in the same direction) is rejected. In various examples, the drive motion (1448 in Figure 14B) is twisted about the Z-axis (see Figures 15 and 16A). The Z-axis gyroscope senses motion based on masses 1454 and 1456 oscillating in opposite directions. Figure 16D illustrates such a movement. Z-axis induced motion is linear in-plane motion (eg, in the X-Y plane) and anti-phase motion (eg, masses 1454 and 1456 oscillate in opposite directions).

The third feature includes a vertical flexure 1426, shown in Figures 14A and 14B. In one example, the vertical flexure 1426 allows the proof-mass frame to deflect more than other parts of the die, such as the inner gimbal 1458, and can be used to adjust the Y-axis induced resonant frequency. The illustrated gimbal structure provides flexures 1426 that deflect only for the Y-axis sensing mode of the gyroscope, in which the mass 1408 rotates about the X-axis, as shown in Figure 16C. Thus, it allows the designer to tune the Y-axis sensed resonant frequency independently of the drive frequency and the X-axis sensed frequency. This enables the center suspension to be modified to minimize quadrature errors in both the X and Y axes.

For example, a fixed portion or substrate may be coupled to anchor 1404 . The fixed portion includes, for example, a packaging substrate. First nonlinear suspension member 1406 can be coupled to anchor 1404 on one side of anchor 1404 . A second nonlinear suspension member 1407 is coupled to the anchor 1404 on the same side of the anchor 1404 . The second nonlinear suspension member may have a shape and position that is a mirror image of the first nonlinear suspension member about the anchor 1404 bisecting plane, although the inventive subject matter is not so limited. One or both of the first nonlinear suspension member and the second nonlinear suspension member may form part of the inner gimbal 1458 of the microelectromechanical die 1400 .

Planar mass 1408 may be coupled to inner gimbal 1458 . The mass may be suspended by a first suspension member 1460 disposed on a first side of the anchor 1404 . The mass may be suspended by a second suspension member 1462 disposed on a second side of the anchor 1404 . A first suspension member 1460 can be coupled opposite a first side of the anchor.

Die 1400 may define a first gap 1464 . The gap 1464 can extend along the first side 1466 of the anchor 1404 . Second gap 1468 may extend along second side 1470 of anchor 1404 . The second gap 1468 may be opposite the first side 1466 . Each of first gap 1464 and second gap 1468 may extend between inner gimbal 1458 and proof-mass 1408 .

The first gap 1464 may extend from the first suspension member 1460 to the second suspension member 1462 . The second gap 1468 may extend from the first suspension member 1460 to the second suspension member 1462 . One or more of the first gap and the second gap may be C-shaped. The first C-shape can define a first opening 1472 that opens toward a second opening 1474 of the second C-shape of the second gap 1468 .

The first C-shape can include a first end portion 1482 and a second end portion 1484, with a central portion 1486 extending between the first end portion and the second end portion. The first end portion and the second end portion may be perpendicular to the central portion. The first sloped portion 1488 can extend between the first end portion 1482 and the central portion, and the second sloped portion 1490 can extend between the second end portion 1484 and the central portion. The first gap may be a mirror image shape of the second gap, and the first gap may be mirrored along the anchor bisecting plane.

The first gap can define a first vertical flexure 1476 and a second vertical flexure 1478 . The second gap can define a third vertical flexure 1426 and a fourth vertical flexure 1480 . Each of the first, second, third and fourth vertical flexures may be elongated and have a length greater than a width. Each respective length may extend away from a respective suspension member. Each respective length may extend away from the anchor bisecting plane 1422 .

In one example, a solid-mass frame structure such as that shown in FIG. 7 relies on a central suspension system to set the drive frequency and X/Y sensing frequency. Thus, all three frequencies and quadrature errors in both axes can be improved simultaneously.

The gimbal structure shown in Figures 14A-D provides an additional degree of freedom to adjust the Y-axis sensing mode. In one example, central flexure 1426 extends away from inner gimbal 1458 along the Y-axis. These flexures can flex vertically. Figure 16C shows the flexure of the flexure enabling rotation of the proof-mass about the X-axis. In one example, one or more flexures 1426 can connect the inner gimbal 1458 to the proof-mass 1408 frame. In one example, the flexures 1426 deflect only for the Y-axis sensing mode of the gyroscope. The addition of out-of-plane flexures allows tuning of the Y-axis induced resonant frequency independently of the drive frequency and the X-axis induced frequency.

In various examples, the drive motion ( 1448 in FIG. 14B ) is twisted about the Z-axis, such as about the central anchor 1404 . FIG. 15 shows the suspension of FIG. 14 torsionally flexed about the Z-axis, according to one example, and FIG. 16A also shows the suspension of FIG. 14 torsionally flexed about the Z-axis, according to one example. 16B shows the suspension of FIG. 14 flexed about the Y-axis, according to one example. In these examples, flexure 1426 exhibits limited flex. However, FIG. 16C shows the suspension of FIG. 14 flexed about the X-axis to flex flexure 1426 according to one example. In one example, the Y-axis induced motion is an out-of-plane twist about the X-axis.

Additional features of Figures 14A-D include curved finger electrodes. These electrodes may not be sensitive to rotationally driven motion. Various examples can include electrodes that are bent about an axis that is normal to the plane in which the electrodes are disposed. Curved finger electrodes (eg, fingers 1450 and 1452) may be less sensitive to rotational drive motion, such as that shown in Figure 16A. In one example, while the proof-mass electrodes are rotating relative to the stator electrodes, the gap distance between the electrodes remains similar or the same. In some examples, this can maintain similar capacitance. However, in some examples, the area of one electrode facing the other varies, which can provide differential capacitance, allowing sensing or rotation about the Z-axis. Thus, provided that the curved electrodes maintain the gap distance between the proof-mass electrodes and the stator electrodes when the die is rotated about an axis normal to the plane in which the electrodes are exposed, there may optionally be no change in capacitance or a lower Capacitance can be changed locally, or the required change in capacitance can be sensed to detect rotation.

The microelectromechanical die 1400 may be coupled to a substrate such as a package to form a packaged integrated circuit. Proof 1408 may be coupled to the substrate at anchor 1404 . The proof-mass may include a first portion 1454 that is movable relative to the anchor 1404 . The first portion may include a first proof-mass electrode 1452 . A second portion 1456 of the proof-mass 1408 opposite the first portion 1454 relative to the anchor 1404 may be movable relative to the anchor 1404 and the first portion 1454 . The second portion 1456 may include a second proof-mass electrode 1452'. Proof 1408 may define a first opening 1492 on a first side of anchor 1404 , such as on a first side of plane 1423 . The first portion 1454 of the proof-mass can be movably coupled in the opening 1492 to the substrate.

First proof-mass electrode 1452 may be one of a first plurality of proof-mass electrodes extending into opening 1492 . The plurality of proof-mass electrodes may be spaced apart from each other. Proof 1408 may define a second opening 1494 on a second side of the anchor, such as on the first side of plane 1423 . The second portion 1456 can be coupled inside the second opening 1494 . The second proof-mass electrode 1452' can be one of a second plurality of spaced-apart proof-mass electrodes extending into the opening 1494.

First stator 1430 may be coupled to the substrate, such as via anchor 1428 , and may include first stator electrode 1450 . The first stator electrode 1450 may extend alongside the first proof-mass electrode 1452 of the proof-mass to form a first electrode pair. The second stator 1431 may be coupled to the substrate and may include a second stator electrode 1451 opposite to the first stator electrode 1450 . The second stator electrode 1451 may extend alongside the second proof-mass electrode 1452' of the second portion 1456 of the proof-mass 1408 to form a second pair of electrodes. The first pair of electrodes may form a first capacitor. The second pair of electrodes may form a second capacitor.

The first proof-mass electrode of the proof-mass may be opposite the second proof-mass electrode on the other side of the anchor, and wherein the first stator electrode may be coupled to the substrate on the other side of the anchor opposite the second anchoring electrode.

The first stator electrode 1450 may be one of a first plurality of stator electrodes that are interleaved and paired with corresponding electrodes of the first plurality of mass electrodes to form a first electrode right. The second stator may be one of a second plurality of stator poles interleaved and paired with corresponding ones of the second plurality of stator poles to form a second pole pair.

In the first mode of vibration of the die 1400, the first portion 1454 of the proof-mass may be about to move away from the second portion 1456 of the proof-mass. The first stator electrode 1450 and the second stator electrode 1451 may be arranged such that a distance between electrodes of the first electrode pair may be inversely proportional to a distance between electrodes of the second electrode pair. The first portion 1454 of the proof-mass may be symmetrical to the second portion 1456 of the proof-mass on the other side of the anchor 1404 . The first stator 1430 may be asymmetrical with respect to the second stator 1431 on the other side of the anchor 1404 .

Figure 18 illustrates a method of making a vibration-suppressing z-axis electrode, according to one embodiment. At 1802, the instance includes forming a proof-mass. This example may include forming an anchor for coupling the proof-mass to the substrate. This example may include forming a first portion on a first side of the anchor, the first portion being movable relative to the anchor and including a first proof-mass electrode. This example may include forming a second portion on a second side of the anchor opposite the first side, the second portion including the second proof-mass electrode. At 1804, the example can include forming a first stator for coupling to the substrate, including forming a first stator electrode for extending alongside a first proof-mass electrode of the proof-proof to form a first electrode pair. At 1806, the example can include forming a second stator for coupling to the substrate, including forming a second stator electrode to extend alongside a second proof-mass electrode of the proof-proof to form a second electrode pair. According to an example, at 1808, the proof-mass, the first stator, and the second stator are formed such that in the first mode of vibration of the proof-mass, the distance between electrodes of the first pair is equal to the distance between electrodes of the second pair of electrodes. is inversely proportional to the distance.

In the first mode of vibration, the first plurality of stator electrodes may be configured to move away from the first plurality of stator electrodes and to move away from the anchor, while the second plurality of stator electrodes may be configured to move toward the the second plurality of stator electrodes and move toward the anchor.

The mass may be configured to vibrate relative to the base plate to vary the distance between the first plurality of stator electrodes and the first plurality of stator electrodes, and to vary the distance between the second plurality of stator electrodes and the second plurality of stator electrodes. The distance between the plurality of stator poles varies.

When the one of the second plurality of stator electrodes closest to the anchor (eg, 1451 ) can be separated by a greater distance from the one of the second plurality of stator electrodes (eg, 1452') closest to the anchor, the The one of the first plurality of stator electrodes (eg, 1452 ) closest to the anchor is spaced a distance from the one of the first plurality of stator electrodes (eg, 1450 ) that is closest to the anchor.

Each of the first proof-mass electrode 1452 and the first stator electrode 1450 may be elongated. The distance D14 between the first-mass electrode and the first stator electrode may be substantially constant along the length L14 of each. Each of the second proof-mass electrode 1452' and the second stator electrode 1451 may be elongated. The distance between the second-mass electrode and the second stator electrode is substantially constant along the length of each.

One or more of the first-mass electrode, the second-mass electrode, the first stator electrode and the second stator electrode may be curved. Each of the electrodes may be bent about an axis about which the mass may be configured to rotate in the second mode of vibration. The axis may be the intersection between plane 1422 and plane 1423 . The mass may be formed into shape by removing material from the wafer, such as by cutting material, such as by etching. The shaping may include deep reactive ion etching.

Die 1400 may be used to sense motion. Vibrations of the first portion of the mass and the second portion of the mass may be excited such that the first and second portions move together and are spaced apart synchronously towards respective first and second stators. Movement of the die along a direction extending between the first portion of the proof-mass and the second portion of the proof-mass may be sensed by measuring the difference in respective capacitance values of the first stator and the second stator. The first-mass electrode 1452 may move towards the first stator electrode 1450 of the first stator 1430, while the second portion 1456 may include a second-mass electrode 1452' moving away from the second stator electrode 1451 of the second stator. Sensing the motion may include sensing a difference between a first capacitance of a first electrode pair comprising the first proof-mass electrode and the first stator electrode and a second electrode pair comprising the second proof-mass electrode and the second stator electrode. induction. The proof-mass may be rotated within the plane of the proof-mass (eg, a plane parallel to planes 1422 and 1423 ) without changing the measured difference in the respective capacitance values of the first and second stators. The rotation may occur without changing the distance between the electrodes of the first electrode pair and without changing the distance between the electrodes of the second electrode pair.

Figure 17 illustrates a method of making a low quadrature error suspension, according to one embodiment. At 1702, the method includes etching material to define an anchor. At 1704, the method includes etching the material to define a first nonlinear suspension member coupled to an anchor on a side of the anchor. At 1706, the method includes etching the material to define a second nonlinear suspension member coupled to the anchor on the same side of the anchor, the second nonlinear suspension member The suspension member has a shape and position in mirror image relation to said first nonlinear suspension member with respect to the anchor bisecting plane. At 1708, the method includes etching the material to define a planar proof-mass at least partially suspended by the first nonlinear suspension member and the second nonlinear suspension member. , such that the proof-mass can rotate around the anchor and slide in a plane parallel to the substrate.

Alternative methods may exist, including methods in which the etching includes deep reactive ion etching. In some optional methods, the first nonlinear suspension member and the second nonlinear suspension member are components of a first set comprising etching the material to define a second set of nonlinear suspensions opposite to the first set Suspension components. Some optional methods include etching a third set of nonlinear suspension members for coupling the anchors to the proof-mass, and etching a fourth set of nonlinear suspension members for coupling the anchors to the proof-mass, wherein the The third and fourth groups have similar elements to the first and second groups and are bisected by a second anchor bisecting plane perpendicular to the first anchor bisecting plane.

Additional information

The subject matter of this document can be described using several examples. Example 1 includes a microelectromechanical die for sensing motion comprising: a fixed portion; an anchor coupled to the fixed portion; a first nonlinear suspension coupled to the anchor on one side of the anchor member; a second nonlinear suspension member coupled to the anchor on the same side of the anchor, the second nonlinear suspension member having a bisecting plane about the anchor bisecting the first nonlinear suspension member a shape and position in a mirror image relationship; and a planar mass suspended at least in part by the first nonlinear suspension member and the second nonlinear suspension member such that the mass can Rotates about the anchor and is able to slide in a plane parallel to the fixed portion.

Example 2 includes the subject matter of Example 1, wherein the first nonlinear suspension member is C-shaped.

Example 3 includes the subject matter of Example 2, wherein the C-shape includes an inner portion coupled to the anchor and extending toward the anchor bisecting plane, and a central portion having a proximal portion and a distal portion, wherein the proximal A side portion is coupled to the inner portion, the distal portion extends away from the anchor along the anchor bisecting plane, and is coupled to an outer portion extending away from the anchor bisecting plane.

Example 4 includes the subject matter of Example 3, wherein said outer portion of said first nonlinear suspension member has a proximal portion coupled to said central portion of said first nonlinear suspension member, and extends away from said a distal portion of an anchor bisector; a fourth portion of said first nonlinear suspension member coupled at a proximal portion thereof to said distal portion of said outer portion and extending toward said anchor to A distal portion of the fourth portion coupled to a fifth portion of the first nonlinear suspension member extending toward the anchor bisecting plane.

Example 5 includes the subject matter of any of Examples 3-4, wherein the inner portion and the outer portion are linear and parallel.

Example 6 includes the subject matter of Example 5, wherein the central section is perpendicular to the inner and outer sections.

Example 7 includes the subject matter of any of Examples 3-6, wherein the central portion is parallel to the anchor bisecting plane.

Example 8 includes the subject matter of any of Examples 1-7, wherein the anchor, the first nonlinear suspension member, the second nonlinear suspension member, and the mass are formed from a single piece of material.

Example 9 includes the subject matter of Example 8, wherein the fixed portion comprises a fixed monolithic material different from the monolithic material of the anchor, the first nonlinear suspension member, the second nonlinear suspension member, and the mass.

Example 10 includes the subject matter of any of Examples 1-9, wherein the fixed portion comprises the same fixed monolithic material as the anchor, the first nonlinear suspension member, the second nonlinear suspension member, and the monolithic material of the mass. Material.

Example 11 includes the subject matter of any of Examples 1-10, wherein the die is sheet-shaped, each of the first nonlinear suspension member and the second nonlinear suspension member has a substantially rectangular cross-section, The height of the cross section is smaller than the width.

Example 12 includes a method comprising: etching a material to define an anchor; etching the material to define a first nonlinear suspension member coupled to the anchor on one side of the anchor; etching the material to define a The same side of the anchor is coupled to a second nonlinear suspension member of the anchor, the second nonlinear suspension member having a mirror image relationship with the first nonlinear suspension member about the anchor bisecting plane shape and location; and etching the material to define a planar mass suspended at least in part by the first nonlinear suspension member and the second nonlinear suspension member such that the The proof-mass is rotatable about the anchor and slidable in a plane parallel to the substrate.

Example 13 includes the subject matter of Example 12, wherein the etching comprises deep reactive ion etching.

Example 14 includes the subject matter of any of Examples 12-13, wherein the first nonlinear suspension member and the second nonlinear suspension member are a first set of components, comprising etching the material to define a The opposite second set of nonlinear suspension members.

Example 15 includes the subject matter of Example 14, including etching a third set of nonlinear suspension members for coupling the anchor to the proof-mass, and etching a fourth set of nonlinear suspension members for coupling the anchor to the proof-mass, Wherein the third and fourth groups have similar elements to the first and second groups and are bisected by a second anchor bisecting plane perpendicular to the first anchor bisecting plane.

Example 16 can include any of the preceding examples, wherein the microelectromechanical die senses motion. The instance may include a substrate. The example may include a proof-mass coupled to the substrate at anchors. The proof-mass may include a first portion movable relative to the anchor, the first portion including a first proof-mass electrode. The example may include a second portion of the proof-mass opposite the first portion relative to the anchor, the second portion being movable relative to the anchor and the first portion, the second portion comprising a second proof-mass electrode. The example can include a first stator coupled to the substrate and including a first stator electrode extending alongside the first-mass electrode of the first portion of the proof-mass to form a first electrode pair. The example may include a second stator coupled to the substrate and including a second stator electrode opposite the first stator electrode and extending alongside the second proof-mass electrode of the second portion of the proof-mass to form a second stator electrode. Two electrode pairs. According to these examples, in the first mode of vibration, in which the first part of the mass moves away from the second part of the mass, the mass, the first stator electrode and the second stator electrode are arranged such that between the electrodes of the first electrode pair The distance between them is inversely proportional to the distance between the electrodes of the second electrode pair.

Example 17 may include any of the preceding examples, wherein the first stator electrode of the proof-mass is opposite the second proof-mass electrode on the other side of the anchor, and wherein the first stator electrode is opposite the second proof-mass electrode on the other side of the anchor. The two anchor electrodes are opposite and coupled to the substrate.

Example 18 may include any of the preceding examples, wherein the first portion of the proof-mass is symmetrical to the second portion of the proof-mass on the other side of the anchor, and the first stator is asymmetrical to the second stator on the other side of the anchor.

Example 19 can include any of the preceding examples, wherein the first pair of electrodes includes a first capacitor and the second pair of electrodes includes a second capacitor.

Example 20 can include any of the preceding examples, wherein each of the first-mass electrode and the first stator electrode is elongated, and the distance between the first-mass electrode and the first stator electrode is along Each has a substantially constant length.

Example 21 can include any of the preceding examples, wherein each of the second-mass electrode and the second stator electrode is elongated, and the distance between the second-mass electrode and the second stator electrode is along each The length of one is substantially constant.

Example 22 may include any of the preceding examples, wherein the proof-mass defines a first opening on the first side of the anchor, a first portion of the proof-mass is movably coupled in the first opening, including a first portion of the first proof-mass electrode. A plurality of proof-mass electrodes extend into the opening and are spaced apart from each other. In this example, the proof-mass may define a second opening on the second side of the anchor, the second portion is coupled into the second opening, and a second plurality of proof-mass electrodes including the second proof-mass electrodes extend into the opening. and spaced apart from each other.

Example 23 may include any of the preceding examples, wherein the first stator electrode is one of a first plurality of stator electrodes, the first plurality of stator electrodes being connected to a corresponding electrode of the first plurality of mass electrodes interleaved and paired to form a first pair of poles; and wherein the second stator pole is one of a second plurality of stator poles, the second plurality of stator poles and a corresponding pole of the second plurality of stator poles interleaved and paired to form a second electrode pair.

Example 24 may include any of the preceding examples, wherein, in the first vibration mode, the first plurality of stator electrodes is configured to move away from the first plurality of stator electrodes and away from the anchor, and the second The plurality of stator electrodes is configured to move toward the second plurality of stator electrodes and toward the anchor.

Example 25 may include any of the preceding examples, wherein the proof-mass is configured to vibrate relative to a substrate to vary a distance between the first plurality of stator electrodes and to cause the first plurality of stator electrodes to vary. The distance between the two plurality of stator electrodes and the second plurality of stator electrodes varies between the one of the second plurality of stator electrodes closest to the anchor and the one of the second plurality of stator electrodes closest to the anchor The one of the first plurality of stator electrodes that is closest to the anchor is at a distance from the one of the first plurality of stator electrodes that is closest to the anchor when one is a greater distance apart.

Example 26 can include any of the preceding examples, wherein the first-mass electrode, the second-mass electrode, the first stator electrode, and the second stator electrode are curved, wherein each of the electrodes is curved about an axis , the mass is configured to rotate about the axis in the second mode of vibration.

Example 27 can include any of the preceding examples and can include forming the proof-mass, including forming an anchor for coupling the proof-mass to the substrate. The example can include forming a first portion on a first side of the anchor, the first portion being movable relative to the anchor and including a first proof-mass electrode. The example may include forming a second portion on a second side of the anchor opposite the first side, the second portion including the second proof-mass electrode. The example may include forming a first stator for coupling to the substrate, including forming a first stator electrode for extending alongside a first proof-mass electrode of the proof-mass to form a first electrode pair. The example may include forming a second stator for coupling to the substrate, including forming a second stator electrode to extend alongside a second proof-mass electrode of the proof-mass to form a second electrode pair. According to this example, the mass, the first stator and the second stator are formed such that in the first mode of vibration of the mass the distance between the electrodes of the first pair is proportional to the distance between the electrodes of the second pair of electrodes Inversely.

Example 28 can include any of the preceding examples, wherein the forming includes deep reactive ion etching.

Example 29 can include any of the preceding examples, wherein forming the first-mass electrode, forming the second-mass electrode, forming the first stator electrode, and forming the second stator electrode includes forming each with a curvature, wherein each One is bent about an axis around which the mass rotates in a second mode of vibration.

Example 30 can include any of the preceding examples, including forming the first capacitor with the first pair of electrodes and forming the second capacitor with the second pair of electrodes.

Example 31 may include any of the preceding examples, wherein forming the first-mass electrode and the first stator electrode comprises forming a first distance therebetween that is substantially constant along the length of the first electrode pair, and forming a second distance between them. The proof-mass electrode and the second stator electrode include a second distance formed therebetween that is substantially constant along the length of the second electrode pair.

Example 32 can include any of the preceding examples, including a method of sensing motion using a microelectromechanical die, comprising. The example may include exciting vibrations of the first portion of the mass and the second portion of the mass such that the first and second portions move together and are spaced apart synchronously toward respective first and second stators. The example may include sensing movement of the die along a direction between the first portion of the proof-mass and the second portion of the proof-mass by measuring a difference in respective capacitance values of the first stator and the second stator. extended.

Example 33 may include any of the preceding examples, wherein the first portion includes a first stator electrode moving towards a first stator electrode of the first stator and the second portion includes a second stator electrode moving away from a second stator The second mass electrode.

Example 34 may include any of the preceding examples, wherein sensing the motion comprises combining a first capacitance of a first electrode pair comprising a first mass electrode and a first stator electrode with a first capacitance comprising a second mass electrode and a second stator electrode. The difference between the second electrode pair of electrodes is sensed.

Example 35 may include any of the preceding examples, comprising rotating the proof-mass in the plane of the proof-mass without changing the measured difference in the respective capacitance values of the first stator and the second stator.

Example 36 may include any of the preceding examples, comprising placing the proof mass on the proof mass without changing the distance between the electrodes of the first electrode pair and without changing the distance between the electrodes of the second electrode pair. in-plane rotation.

Example 37 can include any of the preceding examples, including a microelectromechanical die that senses motion. The instance may include a fixed portion. The instance may include an anchor coupled to the fixed portion. The example can include a first nonlinear suspension member coupled to the anchor on a first side of the anchor. The example may include a second nonlinear suspension member coupled to the anchor on a first side of the anchor, the second nonlinear suspension member having a mirror image relationship with the first nonlinear suspension member about the anchor bisecting plane. shape and position. According to this example, the first nonlinear suspension member and the second nonlinear suspension member are part of an inner gimbal of the microelectromechanical die. The example may include a planar mass consisting of a first suspension member disposed on a first side of the anchor and a second suspension member disposed on a second side of the anchor opposite the first side Suspended, the die defines a first gap extending along a first side of the anchor and a second gap extending along a second side of the anchor opposite the first side, each of the first gap and the second gap extending between the inner gimbal and the proof-mass, wherein the inner gimbal is at least partially suspended by the first nonlinear suspension member and the second nonlinear suspension member such that the proof-mass is rotatable about the anchor and can rotate parallel to the fixed portion slide in the plane.

Example 38 can include any of the preceding examples, wherein the first gap extends from the first suspension member to the second suspension member, and the second gap extends from the first suspension member to the second suspension member.

Example 39 can include any of the preceding examples, wherein the first gap and the second gap are C-shaped, the first C-shape defining a first opening that opens toward a second opening of the second C-shape.

Example 40 can include any of the preceding examples, wherein the first gap defines a first vertical flexure and a second vertical flexure, and the second gap defines a third vertical flexure and a fourth vertical flexure.

Example 41 may include any of the preceding examples, wherein each of the first, second, third, and fourth vertical flexures is elongated, having a length longer than it is wide, and each corresponding length extends away from the corresponding suspension member.

Example 42 can include any of the preceding examples, wherein each respective length extends away from the anchor bisecting plane.

Example 43 can include any of the preceding examples, wherein the first C-shape includes a first end portion and a second end portion, a central portion extending between the first end portion and the second end portion.

Example 44 can include any of the preceding examples, wherein the first end portion and the second end portion are perpendicular to the central portion.

Example 45 can include any of the preceding examples, wherein the first sloped portion extends between the first end portion and the central portion, and the second sloped portion extends between the second end portion and the central portion.

Example 46 can include any of the preceding examples, wherein the first gap is a mirror image shape of the second gap, and the first gap is mirrored along the anchor bisecting plane.

Example 47 can include a method comprising forming a material to define an inner gimbal for coupling with an anchor for anchoring to a substrate. This example can include forming the material to define a first nonlinear suspension member coupled to an anchor on a first side of the anchor. This example may include forming the material to define a second nonlinear suspension member coupled to the anchor on a first side of the anchor, the second nonlinear suspension member having a The shape and position of the member mirrored about the anchor bisecting plane. The example may include forming the material to define a planar mass consisting of a first suspension member disposed on a first side of the anchor and disposed on a second side of the anchor opposite the first side. Suspended by the second suspension member, the first gap extends along the first side of the anchor and the second gap extends along the second side of the anchor opposite the first side, each of the first gap and the second gap The other extends between the proof mass and the inner gimbal.

Example 48 can include any of the preceding examples, wherein the forming includes deep reactive ion etching.

Example 49 may include any of the preceding examples, wherein the first nonlinear suspension member and the second nonlinear suspension member are a first set of components, comprising etching the material to define a third nonlinear suspension member opposite the first set. Two sets of nonlinear suspension members.

Example 50 can include etching a third set of nonlinear suspension members for coupling the anchor to the proof-mass, and etching a fourth set of nonlinear suspension members for coupling the anchor to the proof-mass, wherein the third set The first and fourth sets have similar elements to the first and second sets and are bisected by a second anchor bisecting plane perpendicular to the first anchor bisecting plane.

Example 51 can include any of the preceding examples, wherein etching the first gap and the second gap includes forming each into a C-shape, with the first C-shape of the first gap toward the second C-shape of the second gap wide open.

Example 52 can include a method of sensing motion using a microelectromechanical die comprising rotating a mass relative to an inner gimbal coupled to a substrate via an anchor. The example may include deforming a first nonlinear suspension member that couples the proof-mass to the first side of the anchor above the proof-mass out-of-plane to the plane of the proof-mass. This example may include deforming a second nonlinear suspension member that draws the A mass is coupled to the first side of the anchor. The example may include deforming a first suspension member supporting the mass and disposed on a first side of the anchor, and deforming a second suspension member disposed on a second side of the anchor opposite the first side, tube The core defines a first gap extending along a first side of the anchor and a second gap extending along a second side of the anchor opposite the first side, each of the first and second gaps being in the inner gimbal Extends between the block of mass.

Example 53 may include any of the preceding claims, wherein a first suspension member supporting the mass and disposed on a first side of the anchor is deformed, and a second suspension member disposed on a second side of the anchor opposite the first side is deformed. Deformation of the second suspension member includes causing a first vertical flexure and a second vertical flexure each defined by a first gap and a third vertical flexure and a fourth vertical flexure each defined by a second gap Flexure deformation.

Example 54 may include any of the preceding claims, wherein during the first half of the rotation cycle, the first and second vertical flexures are deformed away from the anchor, and the third and second vertical flexures are deformed. The four vertical flexures deform toward the anchor, and during the second half of the rotation cycle, the first and second vertical flexures deform toward the anchor, and the third and fourth vertical flexures deform toward the anchor. The vertical flexure deforms away from the anchor.

Example 55 may include any of the preceding claims, wherein the deformation of the flexure includes bending.

Example 56 may include any of the preceding claims, wherein the anchor bisects the anchor vertically, and between the first nonlinear suspension member and the second nonlinear suspension member and the first suspension between the member and the second suspension member.

The above detailed description refers to the accompanying drawings, which form a part hereof. The drawings show by way of diagrams specific embodiments to which the invention may be applied. These embodiments are referred to herein as "examples." All publications, patents, and patent documents mentioned herein are hereby incorporated by reference in their entirety, although individually incorporated. If there is a discrepancy between the purposes of this document and the reference document, the purpose of the reference document is considered to be supplementary to the purpose of this document, and if there is an irreconcilable difference between the two, the purpose of this document shall prevail.

Herein, as commonly used in patent documents, the term "a" or "an" means to include one or more, but should be excluded in other cases or when "at least one" or "one or more" is used. Herein, unless otherwise indicated, the term "or" is used to mean a non-exclusive alternative such that "A or B" includes: "A but not B", "B but not A" and "A and B". In the appended claims, the terms "comprising" and "in which" are equivalent to the plain English equivalents of the respective terms "comprising" and "in which". Also, in this document, the terms "comprising" and "comprising" are open-ended, i.e., a system, device, article or step that includes elements other than those listed after such term in a claim is still considered fall within the scope of this claim. Moreover, in the following claims, the terms "first", "second", and "third", etc. are merely used as labels and do not place quantitative requirements on the objects. The foregoing description is by way of illustration and not limitation. In other examples, the above examples (or one or more aspects thereof) may be used in conjunction with each other. Other embodiments may be implemented using certain conventional techniques of the prior art on the basis of understanding the above description.

The Abstract of the Specification is provided under 37 C.F.R. §1.72(b) of the Patent Regulations to allow the reader to quickly ascertain the substance of the technical disclosure. The Abstract of the Specification is submitted not to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped to rationalize the disclosure. This should not be interpreted as indicating that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing as a separate embodiment, and it is contemplated that these embodiments can be combined with each other in various combinations and permutations. The scope of the application should be determined with reference to the appended claims, along with the full range of equivalents to which such claims are entitled.

Claims (13)

1. A microelectromechanical die for sensing motion, comprising: Substrate; a mass coupled to the substrate at anchors, the mass comprising: a first portion movable relative to the anchor, the first portion comprising a first-mass electrode; and a second portion, said second portion being opposite said first portion relative to said anchor, said second portion being movable relative to said anchor and said first portion, said second portion comprising a second mass electrode; a first stator coupled to the base plate and comprising a first stator electrode next to the first-mass electrode of the first portion of the proof-mass extending to form a first electrode pair; and A second stator coupled to the base plate and comprising a second stator electrode opposite the first stator electrode and at all points of the second portion of the proof-mass extending alongside the second proof mass electrodes to form a second pair of electrodes; wherein in a first mode of vibration wherein said first portion of said mass moves away from said second portion of said mass, said mass, said first stator electrode and said second stator electrode arranged such that the distance between the electrodes of the first electrode pair is inversely proportional to the distance between the electrodes of the second electrode pair. 2. The die of claim 1 , wherein the first proof-mass electrode of the proof-mass and the second proof-mass electrode of the proof-mass are respectively located on opposite sides of the anchor, and Wherein the first stator electrode and the second stator electrode are respectively located on two sides of the anchor and oppositely coupled to the substrate. 3. The die according to claim 1, wherein the first portion of the proof mass and the second portion of the proof mass are respectively located on both sides of the anchor and are symmetrical, and the first fixed The stator and the second stator are respectively located on both sides of the anchor asymmetrically. 4. The die of claim 1, wherein the first pair of electrodes comprises a first capacitor and the second pair of electrodes comprises a second capacitor. 5. The die of claim 1 , wherein each of the first-mass electrode and the first stator electrode is elongate, the first-mass electrode and the first The distance between the stator electrodes is substantially constant along the length of each, wherein each of the second-mass electrode and the second stator electrode is elongated, the second-mass electrode The distance from the second stator pole is substantially constant along the length of each. 6. The die of claim 1, wherein the proof-mass defines: a first opening on a first side of the anchor into which the first portion of the proof-mass is movably coupled, a first plurality of proof-mass comprising the first-mass electrode electrodes extend into the first opening and are spaced apart from each other; and a second opening on a second side of the anchor opposite the first side, into which the second portion is coupled, comprising a second plurality of masses of the second proof-mass electrode The bulk electrodes extend into the second openings and are spaced apart from each other. 7. The die of claim 6, wherein the first stator electrode is one of a first plurality of stator electrodes, the first plurality of stator electrodes being connected to one of the first plurality of mass electrodes corresponding electrodes of are interleaved and paired to form said first pair of electrodes; and wherein said second stator electrode is one of a second plurality of stator electrodes, said second plurality of stator electrodes being connected to said second plurality of stator electrodes Corresponding ones of the mass electrodes are interleaved and paired to form the second pair of electrodes. 8. The die of any one of claims 1-7, wherein the first-mass electrode, the second-mass electrode, the first stator electrode, and the second stator electrode are curved, wherein each of the electrodes is bent about an axis, the proof mass is configured to rotate about the axis in a second mode of vibration. 9. A method for sensing motion comprising: Form mass, including: forming an anchor for coupling the proof-mass to a substrate; forming a first portion on a first side of the anchor, the first portion being movable relative to the anchor and comprising a first proof-mass electrode; and forming a second portion on a second side of the anchor opposite the first side, the second portion comprising a second proof-mass electrode; forming a first stator for coupling to the substrate, including forming a first stator electrode for extending alongside the first-mass electrode of the proof-mass to form a first electrode pair; forming a second stator for coupling to the substrate includes forming a second stator electrode for extending alongside the second proof-mass electrode of the proof-mass to form a second electrode pair, Wherein the mass, the first stator and the second stator are formed such that in the first vibration mode of the mass, the distance between the electrodes of the first electrode pair is equal to the distance between the electrodes of the first electrode pair The distance between the electrodes of the two electrode pairs is inversely proportional. 10. The method of claim 9, wherein forming comprises deep reactive ion etching. 11. The method of claim 9, wherein forming the first proof-mass electrode, forming the second proof-mass electrode, forming the first stator electrode and forming the second stator electrode comprise Each is formed with a curvature, each bent about an axis about which the mass rotates in the second mode of vibration. 12. The method of claim 9, comprising forming a first capacitor with the first pair of electrodes and forming a second capacitor with the second pair of electrodes. 13. The method of any one of claims 9-12, wherein forming the first proof-mass electrode and the first stator electrode comprises forming therebetween along the length of the first pair of electrodes a substantially constant first distance, and forming the second mass electrode and the second stator electrode includes forming a second distance therebetween that is substantially constant along the length of the second pair of electrodes.