MEMS device

Abstract

To improve accuracy of detecting angular acceleration.SOLUTION: A sensor unit 3 of a MEMS device 1 comprises: first and second drive frames 20, 30 which are connected and out of phase and are excited in a direction Y; first and second detection frames 40, 50 which are connected to the first and second drive frames 20, 30 so as to be displaceable in a direction X; first and second fixing frames 60, 70; first and second movable electrode members 45, 55 extending from the first and second detection frames 40, 50; first and second fixing electrode member 66, 67 extending from the first fixing frame 60 and facing the first movable electrode member 45 on X1 and X2 sides; and third and fourth fixing electrode members 76, 77 extending from the second fixing frame 70 and facing the second movable electrode member 55 on X1 and X2 sides. The first and second fixing electrode members 66, 67 are connected to the first fixing frame 60 via an IJ 6, and the third and fourth fixing electrode members 76, 77 are connected to the second fixing frame 70 via the IJ 6.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to MEMS devices. [Background technology]

[0002] MEMS (Micro Electro Mechanical System) devices manufactured using semiconductor microfabrication technology are known. As a MEMS device, Patent Document 1 discloses a capacitive MEMS gyro sensor (hereinafter, referred to as a gyro sensor).

[0003] In a gyro sensor, when angular acceleration acts on an element vibrating in a first direction in an in-plane direction parallel to the first direction, the element is displaced in a second direction perpendicular to the first direction due to the Coriolis force, and the displacement of the element in the second direction is detected as a change in capacitance, and the angular acceleration acting on the element is detected based on this change. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] WO2012 / 002514A1

[0005] [overview] A gyro sensor may have a pair of masses connected to each other in a first direction by a spring. In this case, the pair of masses are mechanically connected to each other by the spring, so they vibrate in opposite phases, but are electrically conductive to each other via the spring and have the same potential. As a result, in a gyro sensor having a pair of masses connected to each other by a spring, two symmetrical output voltages cannot be obtained when angular acceleration is applied, and a differential circuit cannot be configured.

[0006] In a gyro sensor, it is possible to obtain two symmetrical output voltages when angular acceleration is applied by vibrating two masses that are not mechanically connected to each other in opposite phases. However, when the two masses are not mechanically connected, it is not easy to precisely synchronize the two masses and vibrate them in opposite phases, so it is difficult to align the two output voltages to be completely opposite phases. As a result, common mode noise may not be canceled out even based on these two output voltages, making it difficult to improve the accuracy of calculating angular acceleration.

[0007] A MEMS device according to an embodiment of the present disclosure includes: A MEMS device comprising: a substrate including a first main surface and a second main surface opposite to the first main surface; a recess recessed from the first main surface to the second main surface side with respect to the substrate; and a sensor unit located within the recess, The sensor unit includes: A first drive frame that is vibrated in a first direction; a second drive frame that is mechanically connected to the first drive frame via a connecting spring and is vibrated in the first direction in an opposite phase to the first drive frame; a first detection frame that is mechanically connected to the first drive frame via a first drive spring, is movable together with the first drive frame in the first direction, and is movable relative to the first drive frame in a second direction perpendicular to the first direction; a second detection frame mechanically connected to the second drive frame via a second drive spring, movable together with the second drive frame in the first direction, and movable relative to the second drive frame in the second direction; A first fixed frame supported immovably against a wall surface that defines the recess; A second fixed frame supported immovably against a wall surface that defines the recess; a first drive unit that vibrates the first drive frame in the first direction by electrostatic attraction; a second driving unit that vibrates the second driving frame in the first direction by electrostatic attraction in an opposite phase to the vibration caused by the first driving unit; a first movable electrode extending from the first detection frame in the first direction; a second movable electrode extending from the second detection frame in the first direction and electrically insulated from the first movable electrode; a first fixed electrode extending from the first fixed frame in the first direction and facing the first movable electrode from a first side in the second direction; a second fixed electrode extending from the first fixed frame in the first direction, facing the first movable electrode from a second side opposite to the first side in the second direction, and electrically insulated from the first fixed electrode; a third fixed electrode extending from the second fixed frame in the first direction, facing the second movable electrode from the first side in the second direction, and having the same potential as the first fixed electrode; a fourth fixed electrode extending from the second fixed frame in the first direction, facing the second movable electrode from the second side in the second direction, and having the same potential as the second fixed electrode; It has the first fixed electrode and the second fixed electrode are each connected to the first fixed frame via an isolation joint, the isolation joint mechanically connecting two members while electrically insulating them from each other; The third fixed electrode element and the fourth fixed electrode element are each connected to the second fixed frame via the isolation joint. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a schematic configuration of a MEMS device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view that illustrates the sensor unit. [Diagram 3]FIG. 3 is a simplified configuration diagram of the sensor unit. [Figure 4] FIG. 4 is an equivalent circuit diagram of FIG. [Diagram 5] FIG. 5 is a simplified configuration diagram of the displacement detection unit. [Figure 6] FIG. 6 is an equivalent circuit diagram of FIG. [Figure 7] FIG. 7 is a plan view illustrating a sensor unit according to the second embodiment of the present invention. [Figure 8] FIG. 8 is a simplified configuration diagram of the sensor unit. [Figure 9] FIG. 9 is an equivalent circuit diagram of FIG. [Figure 10] FIG. 10 is a simplified configuration diagram of the displacement detection unit. [Figure 11] FIG. 11 is an equivalent circuit diagram of FIG. [Figure 12] FIG. 12 is a plan view showing a schematic configuration of a sensor unit according to a modified example. [Figure 13] FIG. 13 is a plan view illustrating a sensor portion according to a further modified example.

[0009] [Detailed Description] Hereinafter, a MEMS device according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. Note that the following description is merely illustrative in nature and is not intended to limit the present disclosure, its applications, or its uses. In addition, the drawings are schematic, and the ratios of dimensions, etc. differ from the actual ones.

[0010] [First embodiment] A MEMS device 1 according to a first embodiment of the present disclosure will be described with reference to Figs. 1 to 6. Fig. 1 is a perspective view showing the MEMS device 1. In the following description, among the directions along each side of the MEMS device 1, the left-right direction in Fig. 1 will be referred to as the Y direction, the up-down direction as the Z direction, and the direction perpendicular to the Y direction and Z direction as the X direction. In particular, in Fig. 1, the diagonally upper right side will be referred to as the X1 side, the diagonally lower left side as the X2 side, the left side as the Y1 side, the right side as the Y2 side, the upper side as the Z1 side, and the lower side as the Z2 side.

[0011] 1, the MEMS device 1 has a device wafer 10 located on the Z2 side and having a sensor portion 3, and a cap wafer 2 located on the Z1 side with respect to the device wafer 10. In Fig. 1, the cap wafer 2 is shown with the X2 side half omitted. The MEMS device 1 is a MEMS sensor manufactured using semiconductor microfabrication technology, and more specifically, is a MEMS gyro sensor.

[0012] The device wafer 10 has a device substrate 11 and a device insulating layer 8 laminated on the Z1 side of the device substrate 11. The device substrate 11 has a first main surface 11a located on the Z1 side and extending parallel to the X and Y directions, and a second main surface 11b located on the opposite side to the first main surface 11a, i.e., the Z2 side, and extending parallel to the X and Y directions. A cavity 12 recessed from the first main surface 11a toward the second main surface 11b side (i.e., the Z2 side) is formed in the device substrate 11.

[0013] The device substrate 11 is made of silicon doped with a high concentration of p-type or n-type impurities and has electrical conductivity.

[0014] The device substrate 11 is processed using semiconductor microfabrication technology to form a cavity 12 and to form a sensor section 3 inside the cavity 12. An electrode pad 4 is formed on a first main surface 11a of the device substrate 11. The electrode pad 4 is electrically connected to the sensor section 3 via device wiring (not shown), and an electrical signal is input / output between the electrode pad 4 and the sensor section 3.

[0015] The electrode pads 4 are located outside the cap wafer 2 in a plan view. The device insulating layer 8 has portions corresponding to the electrode pads 4 removed so that the electrode pads 4 are exposed to the Z1 side even after the sensor unit 3 is sealed by the cap wafer 2.

[0016] Fig. 2 is a plan view of the periphery of the sensor unit 3 of the device wafer 10 as viewed from the Z1 side. In Fig. 2, the device insulating layer 8 and the device wiring are omitted. As shown in Fig. 2, the cavity 12 is defined by a rectangular bottom wall 13 having sides parallel to the X and Y directions, a first vertical wall 14 rising from the edge of the bottom wall 13 on the X1 side to the Z1 side, a second vertical wall 15 rising from the edge of the bottom wall 13 on the Y1 side to the X1 side, a third vertical wall 16 rising from the edge of the bottom wall 13 on the X2 side to the X1 side, and a fourth vertical wall 17 rising from the edge of the bottom wall 13 on the Y2 side to the X1 side.

[0017] The cavity 12 has a pair of fifth and sixth vertical walls 18 and 19 in the X direction that rise from the bottom wall 13 to the Z1 side in the center of the Y direction. The fifth vertical wall 18 extends from the Y center of the first vertical wall 14 to the X2 side and terminates before the X center of the cavity 12. The sixth vertical wall 19 extends from the Y center of the third vertical wall 16 to the X1 side and terminates before the X center of the cavity 12. The fifth and sixth vertical walls 18 and 19 are spaced apart in the X direction.

[0018] That is, the cavity 12 is divided in the Y direction by a pair of fifth vertical walls 18 and sixth vertical walls 19. Specifically, the cavity 12 has a first cavity 12a defined on the Y1 side of the pair of fifth vertical walls 18 and sixth vertical walls 19, a second cavity 12b defined on the Y2 side of the pair of fifth vertical walls 18 and sixth vertical walls 19, and a third cavity 12c defined between the pair of fifth vertical walls 18 and sixth vertical walls 19 in the X direction. The third cavity 12c connects the first cavity 12a and the second cavity 12b in the Y direction.

[0019] The sensor section 3 has a first sensor 3a located in the first cavity 12a, a second sensor 3b located in the second cavity 12b, and a connecting spring 5 located in the third cavity 12c that connects the first sensor 3a and the second sensor 3b in the Y direction.

[0020] The first sensor 3a has a first drive frame 20 that is displaceable in the Y direction relative to the device substrate 11, a first detection frame 40 that is displaceable in the X direction relative to the first drive frame 20 while displacing in the Y direction together with the first drive frame 20, and a first fixed frame 60 that is supported by the bottom wall 13 of the cavity 12 and cannot be displaced relative to the device substrate 11.

[0021] The first drive frame 20 has a first drive first frame 21 extending in the X direction on the Y2 side of the first cavity 12a, a first drive second frame 22 extending from the X1 side end of the first drive first frame 21 to the Y1 side, a first drive third frame 23 extending from the X2 side end of the first drive first frame 21 to the Y1 side, a first drive fourth frame 24 extending from the Y1 side end of the first drive second frame 22 to the X2 side and terminating before the X-direction central portion of the first cavity 12a, and a first drive fifth frame 25 extending from the Y1 side end of the first drive third frame 23 to the X1 side and terminating before the X-direction central portion of the first cavity 12a.

[0022] The sensor unit 3 further has a pair of first drive springs 27 in the Y direction that support the first drive second frame 22 so as to be displaceable in the Y direction relative to the first vertical wall 14. A pair of the first drive springs 27 is also provided in the Y direction between the first drive third frame 23 and the third vertical wall 16. Therefore, the first drive frame 20 is elastically supported by the pair of first drive springs 27 provided in the Y direction on each of both sides in the X direction so as to be displaceable in the Y direction relative to the first vertical wall 14 and the third vertical wall 16, and is spaced from the bottom wall 13 of the cavity 12 on the Z1 side.

[0023] The first drive spring 27 is mechanically connected to the first vertical wall 14 and the third vertical wall 16 while being electrically insulated via an isolation joint (hereinafter referred to as IJ) 6. The IJ6 is a silicon oxide member formed by forming a trench recessed from the first main surface 11a toward the Z2 side in the device substrate 11 made of conductive silicon, for example by etching, and thermally oxidizing the inner wall surface of the trench, so that the inner wall surface grows by thermal oxidation, and mechanically connects and electrically insulates the parts located on both sides of the IJ6.

[0024] The first detection frame 40 has a first detection first frame 41 extending in the X direction at a position adjacent to the Y1 side of the first drive first frame 21, a first detection second frame 42 adjacent to the X2 side of the first drive second frame 22 and extending from the X1 side end of the first detection first frame 41 to the Y1 side, and a first detection third frame 43 adjacent to the X1 side of the first drive third frame 23 and extending from the X2 side end of the first detection first frame 41 to the Y1 side.

[0025] The sensor unit 3 further has a pair of first detection springs 47 in the Y direction that support the first detection second frame 42 so as to be displaceable in the X direction but not displaceable relative to the first driving second frame 22 in the Y direction. A pair of first detection springs 47 are also provided in the Y direction between the first detection third frame 43 and the first driving third frame 23. Therefore, the first detection frame 40 is elastically supported on both sides in the X direction by the pair of first detection springs 47 provided in the Y direction so as to be displaceable in the Y direction but not displaceable relative to the first driving frame 20 in the X direction, and is spaced from the bottom wall 13 of the cavity 12 on the Z1 side.

[0026] A first movable electrode 45 extending to the Y1 side is formed on the first detection first frame 41. A plurality of first movable electrodes 45 are provided at intervals in the X direction.

[0027] The first fixed frame 60 has a first anchor 61 rising from the bottom wall 13 of the cavity 12 to the Z1 side at the central position in the X direction of the first cavity 12a adjacent to the Y1 side of the first detection first frame 41, a first fixed first frame 62 extending to the Y1 side from the first anchor 61, and a first fixed second frame 63 extending to both sides in the X direction from the Y1 side end of the first fixed first frame 62. The first fixed first frame 62 and the first fixed second frame 63 are spaced apart from the bottom wall 13 of the cavity 12 on the Z1 side.

[0028] The first fixed frame 60 is formed with a first fixed electrode 66 and a second fixed electrode 67 extending parallel to each other from the first fixed second frame 63 to the Y2 side. The first fixed electrode 66 faces the first movable electrode 45 from the X1 side. The second fixed electrode 67 faces the first movable electrode 45 from the X2 side. In other words, the first movable electrode 45 may be located between the pair of first fixed electrode 66 and second fixed electrode 67 in the X direction.

[0029] The first fixed frame 60 further has a first fixed third frame 64 extending from the first fixed second frame 63 to the Y2 side and positioned between a first fixed electrode 66 and a second fixed electrode 67 positioned between a pair of first movable electrodes 45 adjacent in the X direction, and a first fixed fourth frame 65 extending in the X direction at the Y2 side end of the first fixed third frame 64. The first fixed third frame 64 and the first fixed fourth frame 65 are at the same potential as the first fixed second frame 63.

[0030] The first fixed electrode 66 and the second fixed electrode 67 are mechanically connected to the first fixed second frame 63 via IJ6 while being electrically insulated. The first fixed electrode 66 and the second fixed electrode 67 are connected to the first fixed third frame 64 via IJ6. The first fixed fourth frame 65 is located between the first fixed electrode 66 and the second fixed electrode 67 and the first detection first frame 41 in the Y direction.

[0031] The first sensor 3a further has a first vibration unit 80 located on the Y2 side of the first sensor 3a and displaces the first sensor 3a to the Y2 side, and a second vibration unit 90 located on the Y1 side of the first sensor 3a and displaces the first sensor 3a to the Y1 side.

[0032] The first vibration unit 80 has a first drive unit 81 that is electrically driven to displace the first sensor 3a toward the Y2 side by using electrostatic attraction, and a first displacement detection unit 86 that detects the displacement of the first sensor 3a in the Y direction.

[0033] The first driving unit 81 has a comb-tooth-shaped first driving movable electrode 82 extending to the Y2 side from a portion of the Y2 side end of the first driving first frame 21 that is located toward the center of the X-direction of the first cavity 12a, and a comb-tooth-shaped first driving fixed electrode 83 having one end connected to the fifth vertical wall 18 and the sixth vertical wall 19 via IJ6 and the other end meshing with the first driving movable electrode 82.

[0034] The first displacement detection unit 86 has a comb-tooth-shaped first displacement detection movable electrode 87 extending to the Y2 side from a portion of the Y2 side end of the first driving first frame 21 located on both sides of the first driving movable electrode 82 in the X direction, and a comb-tooth-shaped first displacement detection fixed electrode 88 having one end connected to the fifth vertical wall 18 and the sixth vertical wall 19 via IJ6 and the other end meshing with the first displacement detection movable electrode 87.

[0035] The second vibration unit 90 has a second drive unit 91 that is electrically driven to displace the first sensor 3a toward the Y1 side by using electrostatic attraction, and a second displacement detection unit 96 that detects the displacement of the first sensor 3a in the Y direction.

[0036] The second driving section 91 has a comb-tooth-shaped second driving movable electrode 92 extending to the Y1 side from a portion of the Y2 side ends of the first driving fourth frame 24 and the first driving fifth frame 25 that is located toward the center of the X direction of the first cavity 12a, and a comb-tooth-shaped second driving fixed electrode 93 having one end connected to the second vertical wall 15 via IJ6 and the other end meshing with the second driving movable electrode 92.

[0037] The second displacement detection unit 96 has a comb-tooth-shaped second displacement detection movable electrode 97 extending to the Y1 side from portions of the Y1 side ends of the first driving fourth frame 24 and the first driving fifth frame 25 that are located on both sides of the second driving movable electrode 92 in the X direction, and a comb-tooth-shaped second displacement detection fixed electrode 98 having one end connected to the second vertical wall 15 via IJ6 and the other end meshing with the second displacement detection movable electrode 97.

[0038] 2, the second sensor 3b is configured symmetrically in the Y direction with respect to the first sensor 3a, and has a second drive frame 30, a second detection frame 50, and a second fixed frame 70. The second drive frame 30, the second detection frame 50, and the second fixed frame 70 are configured symmetrically in the Y direction with respect to the first drive frame 20, the first detection frame 40, and the first fixed frame 60. In each drawing, the reference numerals of the corresponding components of the first drive frame 20, the first detection frame 40, and the first fixed frame 60 are replaced with numbers in the 30s, 50s, and 70s, respectively.

[0039] The second detection frame 50 has a second movable electrode 55 instead of the first movable electrode 45, and the second fixed frame 70 has a third fixed electrode 76 and a fourth fixed electrode 77 instead of the first fixed electrode 66 and the second fixed electrode 67. The third fixed electrode 76 faces the second movable electrode 55 from the X1 side. The fourth fixed electrode 77 faces the second movable electrode 55 from the X2 side. In other words, the second movable electrode 55 may be located between the pair of the third fixed electrode 76 and the fourth fixed electrode 77 in the X direction.

[0040] The second sensor 3b is symmetrical to the first sensor 3a in the Y direction, so a third vibration unit 100 which corresponds to the first vibration unit 80 and displaces the second sensor 3b toward the Y1 side is located on the Y1 side of the second sensor 3b, and a fourth vibration unit 110 which corresponds to the second vibration unit 90 and displaces the second sensor 3b toward the Y2 side is located on the Y2 side of the second sensor 3b.

[0041] The third vibration unit 100 has a third drive unit 101 that is electrically driven to displace the second sensor 3b toward the Y1 side by using electrostatic attraction, and a third displacement detection unit 106 that detects the displacement of the second sensor 3b in the Y direction.

[0042] The third driving unit 101 has a comb-tooth-shaped third driving movable electrode 102 extending to the Y1 side from a portion of the Y1 side end of the second driving first frame 31 that is located toward the center of the X direction of the second cavity 12b, and a comb-tooth-shaped third driving fixed electrode 103 having one end connected to the fifth vertical wall 18 and the sixth vertical wall 19 via IJ6 and the other end meshing with the third driving movable electrode 102.

[0043] The third displacement detection unit 106 has a comb-tooth-shaped third displacement detection movable electrode 107 extending to the Y1 side from portions of the Y1 side end of the second driving first frame 31 located on both sides in the X direction of the third driving movable electrode 102, and a comb-tooth-shaped third displacement detection fixed electrode 108 having one end connected to the fifth vertical wall 18 and the sixth vertical wall 19 via IJ6 and the other end meshing with the third displacement detection movable electrode 107.

[0044] The fourth vibration unit 110 has a fourth drive unit 111 that is electrically driven to displace the second sensor 3b toward the Y2 side by using electrostatic attraction, and a fourth displacement detection unit 116 that detects the displacement of the second sensor 3b in the Y direction.

[0045] The fourth drive unit 111 has a comb-tooth-shaped fourth drive movable electrode 112 extending to the Y2 side from a portion of the Y2 side ends of the second drive fourth frame 34 and the second drive fifth frame 35 that is located toward the center of the X direction of the second cavity 12b, and a comb-tooth-shaped fourth drive fixed electrode 113 having one end connected to the fourth vertical wall 17 via IJ6 and the other end meshing with the fourth drive movable electrode 112.

[0046] The fourth displacement detection unit 116 has a comb-tooth-shaped fourth displacement detection movable electrode 117 extending to the Y2 side from portions of the Y2 side ends of the second driving fourth frame 34 and the second driving fifth frame 35 that are located on both sides of the fourth driving movable electrode 112 in the X direction, and a comb-tooth-shaped fourth displacement detection fixed electrode 118 having one end connected to the fourth vertical wall 17 via IJ6 and the other end meshing with the fourth displacement detection movable electrode 117.

[0047] The connecting spring 5 elastically connects the first sensor 3a and the second sensor 3b in the Y direction. The connecting spring 5 configures the first sensor 3a (i.e., the first driving frame 20 and the first detection frame 40) and the second sensor 3b (i.e., the second driving frame 30 and the second detection frame 50) to vibrate in the Y direction in opposite phases to each other.

[0048] In this embodiment, the connecting spring 5 includes a first connecting spring 5a connected to the first sensor 3a (first drive frame 20), a second connecting spring 5b connected to the second sensor 3b (second drive frame 30), and an IJ6 connecting the first connecting spring 5a and the second connecting spring 5b. Therefore, the first sensor 3a and the second sensor 3b are electrically insulated by the IJ6. In other words, the first movable electrode 45 of the first sensor 3a and the second movable electrode 55 of the second sensor 3b are electrically insulated from each other.

[0049] Next, the electrical connections of the sensor unit 3 will be described.

[0050] The first drive frame 20 is electrically connected to a device wiring (not shown) connected to the electrode pad 4 (see FIG. 1) via at least one of the multiple first drive springs 27. Since the first drive frame 20 is connected to the first detection frame 40 via the first detection springs 47, the first detection frame 40 and the first movable electrode 45 have the same potential as the first drive frame 20.

[0051] The first fixed electrode 66 and the second fixed electrode 67 are connected to the first fixed frame 60 via IJ6 and are electrically insulated from each other and from the first fixed frame 60. The first fixed frame 60 is connected to the second vertical wall 15 via a pair of flex leads 69. The pair of flex leads 69 are connected to the first fixed frame 60 and the second vertical wall 15 via IJ6 at both ends in the Y direction.

[0052] The first fixed electrode 66 and the second fixed electrode 67 are each electrically connected to a pair of flex leads 69 by device wiring (not shown) laminated on the first fixed frame 60 via a device insulating layer 8. The pair of flex leads 69 are each electrically connected to the electrode pads 4 (see FIG. 1) via device wiring (not shown). The flex leads 69 are formed with lower rigidity than the remaining portion, and are easily deformed in the X and Y directions, making it difficult for stress to be transmitted between the first fixed frame 60 and the second vertical wall 15.

[0053] The second drive frame 30 is electrically connected to a device wiring (not shown) connected to the electrode pad 4 (see FIG. 1) via at least one of the multiple second drive springs 37. Since the second drive frame 30 is connected to the second detection frame 50 via the second detection springs 57, the second detection frame 50 and the second movable electrode 55 have the same potential as the second drive frame 30.

[0054] The second driving frame 30 is electrically insulated from the first driving frame 20 at IJ6 of the connecting spring 5. Therefore, the first movable electrode element 45 and the second movable electrode element 55 are electrically insulated from each other.

[0055] The third fixed electrode 76 and the fourth fixed electrode 77 are connected to the second fixed frame 70 via IJ6 and are electrically insulated from each other and from the second fixed frame 70. The second fixed frame 70 is connected to the fourth vertical wall 17 via a pair of flex leads 79. The pair of flex leads 79 are connected to the second fixed frame 70 and the fourth vertical wall 17 via IJ6 at both ends in the Y direction.

[0056] The third fixed electrode 76 and the fourth fixed electrode 77 are each electrically connected to a pair of flex leads 79 by device wiring (not shown) laminated on the second fixed frame 70 via a device insulating layer 8. The pair of flex leads 79 are each electrically connected to the electrode pads 4 (see FIG. 1) via device wiring (not shown).

[0057] The third fixed electrode 76 is electrically connected to the first fixed electrode 66 via device wiring (not shown), and is configured to have the same potential as the first fixed electrode 66. The fourth fixed electrode 77 is electrically connected to the second fixed electrode 67 via device wiring (not shown), and is configured to have the same potential as the second fixed electrode 67.

[0058] The first driving fixed electrode 83 is electrically connected to the electrode pad 4 via device wiring (not shown). The first driving unit 81 configures a capacitor that generates an electrostatic attractive force that displaces the first sensor 3a toward the Y2 side by means of the comb-tooth-shaped first driving movable electrode 82 and the comb-tooth-shaped first driving fixed electrode 83 that meshes with the comb-tooth-shaped first driving movable electrode 82.

[0059] The second driving fixed electrode 93 is electrically connected to the electrode pad 4 via device wiring (not shown). The second driving unit 91 configures a capacitor, by means of the comb-tooth-shaped second driving movable electrode 92 and the comb-tooth-shaped second driving fixed electrode 93 meshing therewith, that generates an electrostatic attractive force that displaces the first sensor 3a toward the Y1 side.

[0060] The third driving fixed electrode 103 is electrically connected to the first driving fixed electrode 83 via device wiring (not shown). The third driving unit 101 configures a capacitor, by means of the comb-tooth-shaped third driving movable electrode 102 and the comb-tooth-shaped third driving fixed electrode 103 meshing therewith, for generating an electrostatic attractive force that displaces the second sensor 3b toward the Y2 side.

[0061] The fourth driving fixed electrode 113 is electrically connected to the second driving fixed electrode 93 via device wiring (not shown). The fourth driving unit 111 configures a capacitor that generates an electrostatic attractive force that displaces the second sensor 3b toward the Y1 side by means of the comb-tooth-shaped fourth driving movable electrode 112 and the comb-tooth-shaped fourth driving fixed electrode 113 that meshes with the comb-tooth-shaped fourth driving movable electrode 112.

[0062] The first displacement detection fixed electrode 88 is electrically connected to the electrode pad 4 via device wiring (not shown). The second displacement detection fixed electrode 98 is electrically connected to the electrode pad 4 via device wiring (not shown). The third displacement detection fixed electrode 108 is electrically connected to the electrode pad 4 via device wiring (not shown). The fourth displacement detection fixed electrode 118 is electrically connected to the electrode pad 4 via device wiring (not shown).

[0063] Next, the circuit configuration of the MEMS device 1 will be described.

[0064] First, a description will be given of the circuit configuration for detecting displacement in the X direction of the first detection frame 40 and the second detection frame 50. Fig. 3 shows a schematic configuration diagram relating to displacement detection in the X direction of the first detection frame 40 and the second detection frame 50 of the sensor unit 3.

[0065] As shown in FIG. 3, a first capacitor C1 is formed by the first movable electrode 45 and the first fixed electrode 66 facing it, a second capacitor C2 is formed by the first movable electrode 45 and the second fixed electrode 67 facing it, a third capacitor C3 is formed by the second movable electrode 55 and the third fixed electrode 76 facing it, and a fourth capacitor C4 is formed by the second movable electrode 55 and the fourth fixed electrode 77 facing it.

[0066] Fig. 4 is an equivalent circuit diagram of the first to fourth capacitors C1 to C4. As shown in Fig. 4, the first capacitor C1 and the third capacitor C3 are connected in series, and the second capacitor C2 and the fourth capacitor C4 are connected in series. A first input voltage drVn, which is an AC voltage, is applied to the first movable electrode 45 via the first driving frame 20, and a second input voltage drVp, which is an AC voltage in opposite phase to the first input voltage drVn, is applied to the second movable electrode 55 via the second driving frame 30. At this time, the first output voltage Vn of the first fixed electrode 66 and the third fixed electrode 76 and the second output voltage Vp of the second fixed electrode 67 and the fourth fixed electrode 77 are detected.

[0067] For example, suppose that angular acceleration about the Z direction acts on the MEMS device 1 in a state in which the first sensor 3a and the second sensor 3b are repeatedly displaced in opposite phases to each other toward the Y1 side and the Y2 side at a predetermined frequency by the first to fourth vibration units 80, 90, 100, 110. At this time, the first detection frame 40 is displaced toward the X2 side or the X1 side due to the Coriolis force generated in the sensor unit 3, while the second detection frame 50 is displaced toward the X1 side or the X2 side in opposite phase to the displacement of the first detection frame 40.

[0068] For example, when the first detection frame 40 is displaced toward the X1 side and the second detection frame 50 is displaced toward the X2 side, the capacitances of the first capacitor C1 and the fourth capacitor C4 increase as the gap between their respective fixed electrodes and movable electrodes decreases, while the capacitances of the second capacitor C2 and the third capacitor C3 decrease as the gap between their respective fixed electrodes and movable electrodes increases.

[0069] As a result, when a first input voltage drVn is applied to the first movable electrode 45 and a second input voltage drVp of the opposite phase is applied to the second movable electrode 55, a first output voltage Vn and a second output voltage Vp that are symmetrical with respect to the intermediate potential are detected. The first output voltage Vn and the second output voltage Vp may each similarly include common mode noise.

[0070] Next, by calculating the difference between the first output voltage Vn and the second output voltage Vp, an output from which common mode noise and the like are cancelled can be obtained. Here, since the first sensor 3a and the second sensor 3b are mechanically connected via the connecting spring 5, it is easy to precisely synchronize the first drive frame 20 and the second drive frame 30 with each other and displace them in the Y direction in opposite phases. Therefore, the first output voltage Vn and the second output voltage Vp, which are in opposite phases, are precisely detected, and an output from which common mode noise is removed can be obtained by taking the difference between them. Based on this output, the angular acceleration acting on the MEMS device 1 can be precisely calculated. That is, a fully differential circuit can be configured by the first to fourth capacitors C1 to C4.

[0071] Next, a circuit configuration for vibrating the first drive frame 20 and the second drive frame 30 in the Y direction will be described. Fig. 5 shows a schematic configuration diagram relating to displacement detection in the Y direction of the first drive frame 20 and the second drive frame 30 of the sensor unit 3.

[0072] As shown in FIG. 5, a first displacement detection capacitor C10a is formed by a comb-tooth-shaped first displacement detection movable electrode 87 and a comb-tooth-shaped first displacement detection fixed electrode 88 meshing therewith, a second displacement detection capacitor C10b is formed by a comb-tooth-shaped second displacement detection movable electrode 97 and a comb-tooth-shaped second displacement detection fixed electrode 98 meshing therewith, a third displacement detection capacitor C10c is formed by a comb-tooth-shaped third displacement detection movable electrode 107 and a comb-tooth-shaped third displacement detection fixed electrode 108 meshing therewith, and a fourth displacement detection capacitor C10d is formed by a comb-tooth-shaped fourth displacement detection movable electrode 117 and a comb-tooth-shaped fourth displacement detection fixed electrode 118 meshing therewith.

[0073] Fig. 6 is an equivalent circuit diagram of the first to fourth displacement detection capacitors C10a to C10d. As shown in Fig. 6, the first displacement detection capacitor C10a and the third displacement detection capacitor C10c are connected in series, and the second displacement detection capacitor C10b and the fourth displacement detection capacitor C10d are connected in series. A first input voltage drVn, which is an AC voltage, is applied to the first displacement detection movable electrode 87 and the second displacement detection movable electrode 97 via the first driving frame 20, and a second input voltage drVp, which is an AC voltage in the opposite phase to the first input voltage drVn, is applied to the third displacement detection movable electrode 107 and the fourth displacement detection movable electrode 117 via the second driving frame 30.

[0074] At this time, the first output voltage Vn1 of the second displacement detection fixed electrode 98 and the third displacement detection fixed electrode 108 and the second output voltage Vp1 of the first displacement detection fixed electrode 88 and the fourth displacement detection fixed electrode 118 are detected.

[0075] For example, suppose that the first sensor 3a is displaced to the Y1 side and the second sensor 3b is displaced to the Y2 side by the first to fourth vibration units 80, 90, 100, 110. At this time, the capacitances of the second displacement detection capacitor C10b and the fourth displacement detection capacitor C10d increase as the opposing areas of their electrodes increase, while the capacitances of the first displacement detection capacitor C10a and the third displacement detection capacitor C10c decrease as the opposing areas between their electrodes decrease.

[0076] As a result, when a first input voltage drVn is applied to the first displacement detection movable electrode 87 and the second displacement detection movable electrode 97 via the first driving frame 20, and a second input voltage drVp of an opposite phase is applied to the third displacement detection movable electrode 107 and the fourth displacement detection movable electrode 117 via the second driving frame 30, a first output voltage Vn1 and a second output voltage Vp1 that are symmetrical with respect to the intermediate potential are detected. The first output voltage Vn1 and the second output voltage Vp1 may each similarly contain common mode noise.

[0077] Next, by calculating the difference between the first output voltage Vn1 and the second output voltage Vp1, an output from which common mode noise and the like are cancelled can be obtained. Therefore, by taking the difference between them, an output from which common mode noise is removed can be obtained. Based on the output, the displacements of the first sensor 3a and the second sensor 3b in the Y direction can be calculated with high accuracy. In addition, by feeding back the calculated displacements of the first sensor 3a and the second sensor 3b in the Y direction, the first sensor 3a and the second sensor 3b can be vibrated in the Y direction with high accuracy and in opposite phase by the first to fourth driving units 81, 91, 101, 111. That is, a fully differential circuit can be configured by the first to fourth displacement detection capacitors C10a to C10d.

[0078] The MEMS device 1 according to the above embodiment has the following advantages.

[0079] (1) MEMS device 1 is The device includes a device substrate 11 including a first main surface 11a and a second main surface 11b facing the first main surface 11a, a cavity 12 recessed from the first main surface 11a toward the second main surface 11b with respect to the device substrate 11, and a sensor unit 3 located within the cavity 12, The sensor unit 3 includes: A first drive frame 20 that is vibrated in the Y direction; A second drive frame 30 that is mechanically connected to the first drive frame 20 via a connecting spring 5 and is vibrated in the Y direction in an opposite phase to the first drive frame 20; a first detection frame 40 that is mechanically connected to the first drive frame 20 via a first detection spring 47 and is displaceable in the Y direction together with the first drive frame 20 and is displaceable in the X direction perpendicular to the Y direction relative to the first drive frame 20; a second detection frame 50 that is mechanically connected to the second drive frame 30 via a second detection spring 57 and is displaceable in the Y direction together with the second drive frame 30 and is displaceable in the X direction relative to the second drive frame 30; a first fixed frame 60 supported immovably relative to a bottom wall 13 defining the cavity 12; a second fixed frame 70 supported immovably relative to the bottom wall 13 defining the cavity 12; a first vibration unit 80 and a second vibration unit 90 that vibrate the first drive frame 20 in the Y direction by electrostatic attraction; a third vibration unit 100 and a fourth vibration unit 110 that vibrate the second drive frame 30 in the Y direction by electrostatic attraction in an opposite phase to the vibrations caused by the first vibration unit 80 and the second vibration unit 90; a first movable electrode 45 extending in the Y direction from the first detection frame 40; a second movable electrode 55 extending in the Y direction from the second detection frame 50 and electrically insulated from the first movable electrode 45; a first fixed electrode 66 extending in the Y direction from the first fixed frame 60 and facing the first movable electrode 45 from the X1 side; a second fixed electrode 67 extending in the Y direction from the first fixed frame 60, facing the first movable electrode 45 from the X2 side, and electrically insulated from the first fixed electrode 66; a third fixed electrode 76 extending in the Y direction from the second fixed frame 70, facing the second movable electrode 55 from the X1 side, and having the same potential as the first fixed electrode 66; a fourth fixed electrode 77 extending in the Y direction from the second fixed frame 70, facing the second movable electrode 55 from the X2 side, and having the same potential as the second fixed electrode 67; It has The first fixed electrode 66 and the second fixed electrode 67 are each connected to the first fixed frame 60 via an IJ6, where the IJ6 mechanically connects the two members while electrically insulating them from each other. The third fixed electrode 76 and the fourth fixed electrode 77 are each connected to the second fixed frame 70 via an IJ6.

[0080] As a result, when an angular acceleration acts on the MEMS device 1 around an axis parallel to the Z direction while the first to fourth vibration units 80, 90, 100, 110 vibrate the first and second drive frames 20, 30 in the Y direction in opposite phases to each other, the first and second detection frames 40, 50 are displaced in the X direction in opposite phases to each other by the Coriolis force. At this time, if a first input voltage drVn and a second input voltage drVp in opposite phases are applied to the first and second movable electrodes 45, 55, respectively, a first output voltage Vn output from the first and third fixed electrodes 66, 76 and a second output voltage Vp output from the second and fourth fixed electrodes 67, 77 are obtained, and the angular acceleration acting on the MEMS device 1 can be accurately calculated based on the first and second output voltages Vn, Vp.

[0081] Here, the first and second output voltages Vn, Vp are symmetrical so that they are voltages of opposite phases. Furthermore, since the first and second drive frames 20, 30 are mechanically connected by the connecting spring 5, it is easy to synchronize them with each other and vibrate them in opposite phases with high precision. Furthermore, the first and second drive frames 20, 30 may be similarly affected by package stress that may occur when the MEMS device 1 is mounted on a circuit board or the like, and by shape variations that may occur when the first and second drive frames 20, 30 are formed by a MEMS formation process. As a result, by taking the difference between the first and second output voltages Vn, Vp, a differential gyro sensor can be configured that can accurately detect changes in angular acceleration by canceling out common mode noise caused by the above-mentioned effects.

[0082] (2) first and second displacement detectors 86, 96 that detect the displacement of the first drive frame 20 in the Y direction; third and fourth displacement detectors 106 and 116 for detecting the displacement of the second drive frame 30 in the Y direction; The device may further include: As a result, the first to fourth displacement detection units 86, 96, 106, 116 can detect the displacement of the first and second drive frames 20, 30 in the Y direction, and the vibration of the first and second drive frames 20, 30 by the first to fourth vibration units 80, 90, 100, 110 can be precisely controlled based on the detected displacement.

[0083] (3) The first drive frame 20 has the same potential as the first movable electrode 45, The second drive frame 30 has the same potential as the second movable electrode 55. The connecting spring 5 is A first connecting spring 5a connected to the first driving frame 20; A second connecting spring 5b connected to the second driving frame 30; IJ6 connects the first connecting spring 5a and the second connecting spring 5b. may have the following structure: As a result, the first and second movable electrodes 45, 55 can be mechanically connected via the first and second detection frames 40, 50, the first and second detection springs 47, 57, the first and second drive frames 20, 30, and the connecting spring 5, while being electrically insulated by IJ6 in the connecting spring 5.

[0084] (4) The first fixed frame 60 is located on the Y1 side of the first detection frame 40, The first fixed electrode 66 and the second fixed electrode 67 extend from the first fixed frame 60 to the Y2 side. A first fixed fourth frame 65 having the same potential as the first fixed frame 60 may be provided between the first detection frame 40 and the tips of the first fixed electrode element 66 and the second fixed electrode element 67 . As a result, when the first detection frame 40 is displaced excessively toward the Y1 side, the first fixed fourth frame 65 is brought into contact with the first detection frame 40, thereby preventing contact between the first detection frame 40 and the first and second fixed electrodes 66, 67. In other words, since it is not necessary to dispose the first and second fixed electrodes 66, 67 at an excessive distance from the first detection frame 40 to ensure a gap between the first detection frame 40 and the first and second fixed electrodes 66, 67, it is easy to ensure the facing area between the first and second fixed electrodes 66, 67 and the first movable electrode 45. This makes it easy to ensure the capacitance of the first and second capacitors C1, C2 configured between the first and second fixed electrodes 66, 67 and the first movable electrode 45, and therefore easy to ensure the detection accuracy of the first sensor 3a. The first fixed fourth frame 65 constitutes a stopper portion according to the present disclosure.

[0085] (5) The first fixed fourth frame 65 may be supported by the first fixed third frame 64 extending from the first fixed second frame 63 to the Y2 side. As a result, the first fixed fourth frame 65 (stopper portion) can be suitably supported by the first fixed frame 60 and configured to have the same potential as the first fixed frame 60. Therefore, the first fixed third frame 64 constitutes a stopper support portion according to the present disclosure.

[0086] (6) The first fixed third frame 64 is located between the first fixed electrode element 66 and the second fixed electrode element 67 . As a result, the first and second fixed electrodes 66, 67 can be electrically insulated by the first fixed third frame 64 (stopper support portion) interposed therebetween.

[0087] (7) The first fixed third frame 64 is connected to each of the first fixed electrode element 66 and the second fixed electrode element 67 via IJ6. As a result, since the first and second fixed electrodes 66, 67 are supported by the first fixed third frame 64 (stopper support portion), the supporting rigidity of the first and second fixed electrodes 66, 67 can be easily increased.

[0088] Although the above-mentioned advantages (4) to (7) have been described for the first sensor 3a, the same advantages can also be achieved for the second sensor 3b.

[0089] [Second embodiment] Next, a MEMS device 200 according to a second embodiment of the present disclosure will be described with reference to Fig. 7 to Fig. 11. In the following description, the same components as those in the MEMS device 1 according to the first embodiment are given the same reference numerals, and corresponding components are given the same reference numerals in the 200 and 300 ranges, and description thereof will be omitted.

[0090] 7 is a plan view of the MEMS device 200. As shown in FIG. 7, the MEMS device 200 has first and second movable electrodes 245, 255 like the MEMS device 1 according to the first embodiment, but differs from the MEMS device 1 in that it further has a third movable electrode 345 and a fourth movable electrode 355. Furthermore, the MEMS device 200 has first to fourth fixed electrodes 266, 267, 276, 277 like the MEMS device 1, but differs from the MEMS device 1 in that it further has a fifth fixed electrode 366, a sixth fixed electrode 367, a seventh fixed electrode 376, and an eighth fixed electrode 377. Furthermore, the MEMS device 200 differs from the MEMS device 1 in the arrangement of the IJ6.

[0091] In this embodiment, the portions corresponding to the first detection frame 40 (first detection frame 41) and the second detection frame 50 (second detection frame 51) in the MEMS device 1 are divided by IJ6 provided at the center thereof into a first detection frame 240 and a second detection frame 250 located on the X1 side of the IJ6, and a third detection frame 340 and a fourth detection frame 350 located on the X2 side. The first detection frame 240 and the third detection frame 340 are mechanically connected while being electrically insulated by the IJ6. The second detection frame 250 and the fourth detection frame 350 are mechanically connected while being electrically insulated by the IJ6.

[0092] The first movable electrode 245 extends from the first detection first frame 241 to the Y1 side. The second movable electrode 255 extends from the second detection first frame 251 to the Y2 side. The third movable electrode 345 extends from the third detection first frame 341 to the Y1 side. The fourth movable electrode 355 extends from the fourth detection first frame 351 to the Y2 side. The third movable electrode 345 is electrically connected to the second movable electrode 255 via device wiring (not shown) and is set to the same potential as the second movable electrode 255. The fourth movable electrode 355 is electrically connected to the first movable electrode 245 via device wiring (not shown) and is set to the same potential as the first movable electrode 245.

[0093] The first movable electrode 245 is located on the X1 side with respect to the third movable electrode 345. The second movable electrode 255 is located on the X1 side with respect to the fourth movable electrode 355. The first movable electrode 245 is arranged symmetrically with respect to the fourth movable electrode 355 about the center of the sensor unit 3 in the X and Y directions. The second movable electrode 255 is arranged symmetrically with respect to the third movable electrode 345 about the center of the sensor unit 3.

[0094] The first to fourth fixed electrodes 266, 267, 276, 277 respectively correspond to the first to fourth fixed electrodes 66, 67, 76, 77 of the MEMS device 1. The first fixed electrode 266 faces the first movable electrode 245 from the X1 side, and the second fixed electrode 267 faces the first movable electrode 245 from the X2 side. The third fixed electrode 276 faces the second movable electrode 255 from the X1 side, and the fourth fixed electrode 277 faces the second movable electrode 255 from the X2 side.

[0095] The fifth and sixth fixed electrodes 366, 367 are connected to the first fixed second frame 63 via IJ6 and extend to the Y2 side. The fifth and sixth fixed electrodes 366, 367 are electrically insulated from each other. The seventh and eighth fixed electrodes 376, 377 are connected to the second fixed second frame 73 via IJ6 and extend to the Y1 side. The seventh and eighth fixed electrodes 376, 377 are electrically insulated from each other.

[0096] The fifth fixed electrode 366 faces the third movable electrode 345 from the X2 side. The sixth fixed electrode 367 faces the third movable electrode 345 from the X1 side. The seventh fixed electrode 376 faces the fourth movable electrode 355 from the X2 side. The eighth fixed electrode 377 faces the fourth movable electrode 355 from the X1 side.

[0097] The fifth fixed electrode 366 is electrically connected to the first fixed electrode 266 via device wiring (not shown) and has the same potential as the first fixed electrode 266. The sixth fixed electrode 367 is electrically connected to the second fixed electrode 267 via device wiring (not shown) and has the same potential as the second fixed electrode 267. The seventh fixed electrode 376 is electrically connected to the fifth fixed electrode 366 via device wiring (not shown) and has the same potential as the fifth fixed electrode 366 (i.e., the same potential as the first fixed electrode 266). The eighth fixed electrode 377 is electrically connected to the sixth fixed electrode 367 via device wiring (not shown) and has the same potential as the sixth fixed electrode 367 (i.e., the same potential as the second fixed electrode 267).

[0098] Regarding the arrangement of the IJ6, the connecting spring 5 is not provided with the IJ6, and the first connecting spring 5a and the second connecting spring 5b are directly connected. Meanwhile, the first and second driving frames 20, 30 are provided with the IJ6 at their connection portions with the first and second driving springs 27, 37 and at their connection portions with the first and second detection springs 47, 57. Therefore, the first and second driving frames 20, 30 are set to the same potential, and are electrically insulated from the first to fourth detection frames 240, 250, 340, 350 by the IJ6.

[0099] Fig. 8 shows a simplified schematic configuration of the MEMS device 200. As shown in Fig. 8, in the MEMS device 200, similarly to the MEMS device 1, a first capacitor C1 is formed by the first movable electrode 245 and a first fixed electrode 266 facing thereto, a second capacitor C2 is formed by the first movable electrode 245 and a second fixed electrode 267 facing thereto, a third capacitor C3 is formed by the second movable electrode 255 and a third fixed electrode 276 facing thereto, and a fourth capacitor C4 is formed by the second movable electrode 255 and a fourth fixed electrode 277 facing thereto.

[0100] In the MEMS device 200, a fifth capacitor C5 is further formed by the third movable electrode 345 and a fifth fixed electrode 366 facing it, a sixth capacitor C6 is formed by the third movable electrode 345 and a sixth fixed electrode 367 facing it, a seventh capacitor C7 is formed by the fourth movable electrode 355 and a seventh fixed electrode 376 facing it, and an eighth capacitor C8 is formed by the fourth movable electrode 355 and an eighth fixed electrode 377 facing it.

[0101] That is, in the MEMS device 200, a differential circuit composed of first to fourth capacitors C1 to C4 is configured on the X1 side, similar to the MEMS device 1, with the center of the sensor unit 3 in the X and Y directions in between, and a further differential circuit composed of fifth to eighth capacitors C1 to C8 is configured on the X2 side. The differential circuit configured on the X2 side is point-symmetrical about the center of the sensor unit 3 with respect to the differential circuit configured on the X1 side.

[0102] FIG. 9 is an equivalent circuit diagram of the sensor unit 3 of the MEMS device 200. As shown in FIG.

[0103] Fig. 10 is a schematic diagram showing the configuration of the first drive frame 20 and the second drive frame 30 of the sensor unit 3 with respect to displacement detection in the Y direction. As shown in Fig. 10, first to fourth displacement detection capacitors C10a to C10d are configured in the same manner as in the MEMS device 1, but since the first and second drive frames 20 and 30 are set to the same potential, only the wiring connection is different from that of the MEMS device 1 in that only the first input voltage drVn is applied. Fig. 11 is an equivalent circuit diagram corresponding to the schematic configuration diagram of Fig. 10.

[0104] The MEMS device 200 according to this embodiment provides the following advantages.

[0105] (1) The MEMS device 200 has the configuration of the MEMS device 1, a third detection frame 340 connected to first detection frame 240 via IJ6; a fourth detection frame 350 connected to second detection frame 250 via IJ6; a third movable electrode 345 extending in the Y direction from the third detection frame 340 and having the same potential as the second movable electrode 255; a fourth movable electrode 355 extending in the Y direction from the fourth detection frame 350, electrically insulated from the third movable electrode 345, and at the same potential as the first movable electrode 245; a fifth fixed electrode 366 extending in the Y direction from the first fixed frame 260, facing the third movable electrode 345 from the X2 side, and having the same potential as the first fixed electrode 266; a sixth fixed electrode 367 extending in the Y direction from the first fixed frame 260, facing the third movable electrode 345 from the X1 side, electrically insulated from the fifth fixed electrode 366, and at the same potential as the second fixed electrode 267; a seventh fixed electrode 376 extending in the Y direction from the second fixed frame 270, facing the fourth movable electrode 355 from the X2 side, and having the same potential as the fifth fixed electrode 366; an eighth fixed electrode 377 extending in the Y direction from the second fixed frame 270, facing the fourth movable electrode 355 from the X1 side, and having the same potential as the sixth fixed electrode 367; It is equipped with The fifth fixed electrode 366 and the sixth fixed electrode 367 are each connected to the first fixed frame 260 via IJ6. The seventh fixed electrode 376 and the eighth fixed electrode 377 are each connected to the second fixed frame 270 via IJ6.

[0106] As a result, in addition to the fully differential circuit formed by the first and second movable electrodes 245, 255 and the first to fourth fixed electrodes 266, 267, 276, 277, a further fully differential circuit can be formed by the third and fourth movable electrodes 345, 355 and the fifth to eighth fixed electrodes 366, 367, 376, 377. Moreover, since the first to fourth movable electrodes 245, 255, 345, 355 are mechanically connected, common mode noise that may occur in both circuits can be cancelled out, and angular acceleration can be detected with even greater accuracy.

[0107] (2) The first drive frame 20 and the second drive frame 30 may be at the same potential. As a result, the first drive frame 20 and the second drive frame 30 can be mechanically connected without the intervention of the IJ6.

[0108] (3) The first movable electrode 245 is located on the X1 side with respect to the third movable electrode 345, The second movable electrode 255 may be located on the X1 side with respect to the fourth movable electrode 355. As a result, the first and third movable electrodes 245, 345, to which input voltages of opposite phases are applied, are arranged symmetrically in the Y direction, and the second and fourth movable electrodes 255, 355, to which input voltages of opposite phases are similarly applied, are arranged symmetrically in the Y direction. This cancels out common mode noise that may occur symmetrically in the Y direction in the sensor unit 3, thereby enabling angular acceleration to be detected with even greater accuracy.

[0109] (4) The first movable electrode 245 is disposed symmetrically with respect to the center of the sensor unit 3 in the X direction and the Y direction with respect to the fourth movable electrode 355; The second movable electrode 255 may be disposed point-symmetrically with respect to the third movable electrode 345 with respect to the center of the sensor unit 3 . As a result, the first and fourth movable electrodes 245, 355, to which input voltages of the same phase are applied, are arranged point-symmetrically in the sensor unit 3, and the second and third movable electrodes 255, 345, to which input voltages of the same phase are similarly applied, are arranged point-symmetrically in the sensor unit 3. This effectively cancels out common mode noise that may occur point-symmetrically about the center in the sensor unit 3, thereby enabling even more accurate detection of angular acceleration.

[0110] The present disclosure is not limited to the configurations described in the above embodiments, and various modifications are possible.

[0111] Fig. 12 shows a MEMS device 300 according to a modified example. As shown in Fig. 12, MEMS device 300 is modified based on MEMS device 1 so that first detection frame 320 and second detection frame 330 are connected by connecting spring 305 that is expandable and contractible in the X direction. First detection frame 320 and second detection frame 330 are mechanically connected while being electrically insulated from each other by IJ6 at both ends of connecting spring 305 in the Y direction. This makes it easier to displace first and second detection frames 320, 330 in the X direction in opposite phases while being more synchronized, and allows angular acceleration to be detected with greater accuracy.

[0112] Fig. 13 shows a MEMS device 400 according to a further modification. As shown in Fig. 13, MEMS device 400 is modified based on MEMS device 200 so that first detection frame 420 (and / or third detection frame 440) and second detection frame 430 (and / or fourth detection frame 450) are connected by connecting spring 405 that is expandable in the X direction. First detection frame 420 and second detection frame 430 are mechanically connected to each other while being electrically insulated from each other by IJ6 at both ends of connecting spring 405 in the Y direction. This makes it easier to displace first and second detection frames 420 and 430 in the X direction in opposite phases while being more synchronized, and allows angular acceleration to be detected with higher accuracy.

[0113] [Note] The MEMS device according to the present disclosure provides the following aspects.

[0114] [Aspect 1] A MEMS device comprising: a substrate including a first main surface and a second main surface opposite to the first main surface; a recess recessed from the first main surface to the second main surface side with respect to the substrate; and a sensor unit located within the recess, The sensor unit includes: A first drive frame that is vibrated in a first direction; a second drive frame that is mechanically connected to the first drive frame via a connecting spring and is vibrated in the first direction in an opposite phase to the first drive frame; a first detection frame that is mechanically connected to the first drive frame via a first detection spring, is displaceable together with the first drive frame in the first direction, and is displaceable relative to the first drive frame in a second direction perpendicular to the first direction; a second detection frame mechanically connected to the second drive frame via a second detection spring, displaceable together with the second drive frame in the first direction and displaceable relative to the second drive frame in the second direction; A first fixed frame supported immovably against a wall surface that defines the recess; A second fixed frame supported immovably against a wall surface that defines the recess; a first vibration unit that vibrates the first drive frame in the first direction by electrostatic attraction; a second vibration unit that vibrates the second drive frame in the first direction by electrostatic attraction in an opposite phase to the vibration by the first vibration unit; a first movable electrode extending from the first detection frame in the first direction; a second movable electrode extending from the second detection frame in the first direction and electrically insulated from the first movable electrode; a first fixed electrode extending from the first fixed frame in the first direction and facing the first movable electrode from a first side in the second direction; a second fixed electrode extending from the first fixed frame in the first direction, facing the first movable electrode from a second side opposite to the first side in the second direction, and electrically insulated from the first fixed electrode; a third fixed electrode extending from the second fixed frame in the first direction, facing the second movable electrode from the first side in the second direction, and having the same potential as the first fixed electrode; a fourth fixed electrode extending from the second fixed frame in the first direction, facing the second movable electrode from the second side in the second direction, and having the same potential as the second fixed electrode; It has the first fixed electrode and the second fixed electrode are each connected to the first fixed frame via an isolation joint, the isolation joint mechanically connecting two members while electrically insulating them from each other; A MEMS device, wherein the third fixed electrode and the fourth fixed electrode are each connected to the second fixed frame via the isolation joint.

[0115] [Aspect 2] a first displacement detection unit that detects a displacement of the first drive frame in the first direction; a second displacement detection unit that detects a displacement of the second drive frame in the first direction; 2. The MEMS device of embodiment 1, further comprising:

[0116] [Aspect 3] the first drive frame is at the same potential as the first fixed electrode element; the second drive frame is at the same potential as the second fixed electrode element; The connecting spring is a first connecting spring connected to the first driving frame; a second connecting spring connected to the second driving frame; the isolation joint connecting the first connecting spring and the second connecting spring; having 3. The MEMS device according to embodiment 1 or 2.

[0117] [Aspect 4] a third detection frame connected to the first detection frame via the isolation joint; and a fourth detection frame connected to the second detection frame via the isolation joint; and a third movable electrode extending from the third detection frame in the first direction and having the same potential as the second movable electrode; a fourth movable electrode extending in the first direction from the fourth detection frame, electrically insulated from the third movable electrode, and at the same potential as the first movable electrode; a fifth fixed electrode extending from the first fixed frame in the first direction, facing the third movable electrode from the second side in the second direction, and having the same potential as the first fixed electrode; a sixth fixed electrode extending from the first fixed frame in the first direction, facing the third movable electrode from the first side in the second direction, electrically insulated from the fifth fixed electrode, and at the same potential as the second fixed electrode; a seventh fixed electrode extending from the second fixed frame in the first direction, facing the fourth movable electrode from the second side in the second direction, and having the same potential as the fifth fixed electrode; an eighth fixed electrode extending from the second fixed frame in the first direction, facing the fourth movable electrode from the first side in the second direction, and having the same potential as the sixth fixed electrode; It is equipped with the fifth fixed electrode element and the sixth fixed electrode element are each connected to the first fixed frame via the isolation joint, the seventh fixed electrode element and the eighth fixed electrode element are each connected to the second fixed frame via the isolation joint; 3. The MEMS device according to embodiment 1 or 2.

[0118] [Aspect 5] The first drive frame and the second drive frame are at the same potential. 5. The MEMS device of embodiment 4.

[0119] [Aspect 6] the first movable electrode is located on the first side in the second direction with respect to the third movable electrode, the second movable electrode is located on the first side in the second direction with respect to the fourth movable electrode; 6. The MEMS device according to embodiment 4 or 5.

[0120] [Aspect 7] the first movable electrode is disposed symmetrically with respect to a center of the sensor unit in the first direction and the second direction with respect to the fourth movable electrode; the second movable electrode is disposed point-symmetrically with respect to the center of the sensor unit with respect to the third movable electrode; The MEMS device according to any one of embodiments 4 to 6.

[0121] [Aspect 8] the first fixed frame is located on a first side of the first detection frame in the first direction, the first fixed electrode element and the second fixed electrode element extend from the first fixed frame to a second side opposite to the first side in the first direction, a stopper portion having the same potential as the first fixed frame is provided between the first detection frame and the tips of the first and second fixed electrodes; The MEMS device according to any one of embodiments 1 to 7.

[0122] [Aspect 9] The stopper portion is supported by a stopper support portion extending from the first fixing frame to the second side in the first direction. 9. The MEMS device of embodiment 8.

[0123] [Aspect 10] The stopper support portion is located between the first fixed electrode element and the second fixed electrode element. 10. The MEMS device of embodiment 9.

[0124] [Aspect 11] the stopper support portion is connected to each of the first fixed electrode element and the second fixed electrode element via the isolation joint; 11. The MEMS device according to embodiment 9 or 10. [Explanation of symbols]

[0125] 1. MEMS Device 2 Cap wafer 3 Sensor section 4 Electrode pads 5 Connecting spring 6 Isolation joint 8 Device insulation layer 10 Device wafer 11 Device substrate 12 Cavity 20 First drive frame 27 First drive spring 30 Second drive frame 37 Second drive spring 40 First detection frame 45 First movable electrode 47 First detection spring 50 Second detection frame 55 Second movable electrode 57 Second detection spring 60 1st fixed frame 66 1st fixed electrode 67 Second fixed electrode 70 Second fixed frame 76 Third fixed electrode 77 4th fixed electrode 80 First vibration section 81 First Drive Unit 86 First displacement detection unit 90 Second vibration section 91 Second Drive Unit 96 Second displacement detection unit 100 Third vibration section 101 3rd Drive Unit 106 Third displacement detection unit 110 Fourth vibration section 111 4th Drive Unit 116 Fourth Displacement Detection Unit C1 First capacitor C2 Second capacitor C3 Third capacitor C4 4th capacitor drVn 1st input voltage drVp Second input voltage Vn 1st output voltage Vp Second output voltage

Claims

1. A MEMS device comprising: a substrate including a first main surface and a second main surface opposite to the first main surface; a recess recessed from the first main surface to the second main surface side with respect to the substrate; and a sensor unit located within the recess, The sensor unit includes: a first drive frame that is vibrated in a first direction; a second drive frame that is mechanically connected to the first drive frame via a connecting spring and is vibrated in the first direction in an opposite phase to the first drive frame; a first detection frame that is mechanically connected to the first drive frame via a first drive spring, is displaceable together with the first drive frame in the first direction, and is displaceable relative to the first drive frame in a second direction perpendicular to the first direction; a second detection frame mechanically connected to the second drive frame via a second drive spring, displaceable together with the second drive frame in the first direction and displaceable relative to the second drive frame in the second direction; A first fixed frame supported immovably against a wall surface that defines the recess; A second fixed frame supported immovably against a wall surface that defines the recess; a first vibration unit that vibrates the first drive frame in the first direction by electrostatic attraction; a second vibration unit that vibrates the second drive frame in the first direction by electrostatic attraction in an opposite phase to the vibration by the first vibration unit; a first movable electrode extending from the first detection frame in the first direction; a second movable electrode extending from the second detection frame in the first direction and electrically insulated from the first movable electrode; a first fixed electrode extending from the first fixed frame in the first direction and facing the first movable electrode from a first side in the second direction; a second fixed electrode extending from the first fixed frame in the first direction, facing the first movable electrode from a second side opposite to the first side in the second direction, and electrically insulated from the first fixed electrode; a third fixed electrode extending from the second fixed frame in the first direction, facing the second movable electrode from the first side in the second direction, and having the same potential as the first fixed electrode; a fourth fixed electrode extending from the second fixed frame in the first direction, facing the second movable electrode from the second side in the second direction, and having the same potential as the second fixed electrode; It has the first fixed electrode and the second fixed electrode are each connected to the first fixed frame via an isolation joint, the isolation joint mechanically connecting two members while electrically insulating them from each other; A MEMS device, wherein the third fixed electrode and the fourth fixed electrode are each coupled to the second fixed frame via the isolation joint.

2. a first displacement detection unit that detects a displacement of the first drive frame in the first direction; a second displacement detection unit that detects a displacement of the second drive frame in the first direction; The MEMS device of claim 1 further comprising:

3. the first drive frame is at the same potential as the first fixed electrode element; the second drive frame is at the same potential as the second fixed electrode element; The connecting spring is a first connecting spring connected to the first driving frame; a second connecting spring connected to the second driving frame; the isolation joint connecting the first connecting spring and the second connecting spring; having 3. The MEMS device according to claim 1 or 2.

4. a third detection frame connected to the first detection frame via the isolation joint; and a fourth detection frame connected to the second detection frame via the isolation joint; and a third movable electrode extending from the third detection frame in the first direction and having the same potential as the second movable electrode; a fourth movable electrode extending from the fourth detection frame in the first direction, electrically insulated from the third movable electrode, and at the same potential as the first movable electrode; a fifth fixed electrode extending from the first fixed frame in the first direction, facing the third movable electrode from the second side in the second direction, and having the same potential as the first fixed electrode; a sixth fixed electrode extending from the first fixed frame in the first direction, facing the third movable electrode from the first side in the second direction, electrically insulated from the fifth fixed electrode, and at the same potential as the second fixed electrode; a seventh fixed electrode extending from the second fixed frame in the first direction, facing the fourth movable electrode from the second side in the second direction, and having the same potential as the fifth fixed electrode; an eighth fixed electrode extending from the second fixed frame in the first direction, facing the fourth movable electrode from the first side in the second direction, and having the same potential as the sixth fixed electrode; Equipped with the fifth fixed electrode element and the sixth fixed electrode element are each connected to the first fixed frame via the isolation joint, the seventh fixed electrode element and the eighth fixed electrode element are each connected to the second fixed frame via the isolation joint; 3. The MEMS device according to claim 1 or 2.

5. The first drive frame and the second drive frame are at the same potential. The MEMS device of claim 4 .

6. the first movable electrode is located on the first side in the second direction with respect to the third movable electrode, the second movable electrode is located on the first side in the second direction with respect to the fourth movable electrode; The MEMS device of claim 4 .

7. the first movable electrode is disposed symmetrically with respect to a center of the sensor unit in the first direction and the second direction with respect to the fourth movable electrode; the second movable electrode is disposed point-symmetrically with respect to the center of the sensor unit with respect to the third movable electrode; The MEMS device of claim 6.

8. the first fixed frame is located on a first side of the first detection frame in the first direction, the first fixed electrode and the second fixed electrode extend from the first fixed frame to a second side opposite to the first side in the first direction, a stopper portion having the same potential as the first fixed frame is provided between the first detection frame and a tip of the first fixed electrode element and the second fixed electrode element; 3. The MEMS device according to claim 1 or 2.

9. The stopper portion is supported by a stopper support portion extending from the first fixing frame to the second side in the first direction. The MEMS device of claim 8.

10. The stopper support portion is located between the first fixed electrode element and the second fixed electrode element. The MEMS device of claim 9.

11. the stopper support portion is connected to each of the first fixed electrode element and the second fixed electrode element via the isolation joint; The MEMS device of claim 10.

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