JP2017111003A - MEMS device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique that can suppress movable unit from being excited by other axis in MEMS devices exciting a movable unit by an opposing electrode pair and a slide electrode.SOLUTION: A MEMS device disclosed by the present specification comprises: a base plate; a first movable unit that is elastically supported with respect to the base plate; a first electrode structure that is provided with a first opposing electrode pair and a first slide electrode; and a second electrode structure that is provided with a second opposing electrode pair and a second slide electrode. One of the first opposing electrode pair and the first slide electrode is not movable in a slide direction with respect to the first movable unit. One of the second opposing electrode pair and the second slide electrode is not movable in the slide direction with respect to the first movable unit. Regarding the slide direction, the first slide electrode is arranged with the first slide electrode off-set to the first opposing electrode pair, and the second slide electrode is arranged without being off-set to the second opposing electrode pair.SELECTED DRAWING: Figure 1

Description

  The present specification discloses a MEMS device.

  Patent Document 1 discloses a MEMS device. A MEMS device moves in a predetermined sliding direction with respect to a substrate, a movable part elastically supported with respect to the substrate, a counter electrode pair disposed at the same potential and facing each other, and the counter electrode pair It is possible to provide an electrode structure including a slide electrode disposed between the counter electrode pair. The counter electrode pair is immovable in the sliding direction with respect to the movable part. With respect to the slide direction, the slide electrode is arranged offset with respect to the counter electrode pair.

JP 2013-97139 A

  When the electrode structure used in the MEMS device of Patent Document 1 is to be applied to an actuator that excites the movable part in the sliding direction, the following problems occur. In the electrode structure used in the MEMS device of Patent Document 1, the slide electrode is offset with respect to the counter electrode pair and is inclined with respect to the counter electrode pair with respect to the slide direction. Therefore, in this electrode structure, when an excitation voltage is applied between the counter electrode pair and the slide electrode, the movable part is excited not only in the sliding direction but also in a direction orthogonal to the sliding direction. . For example, when this electrode structure is applied as an actuator that excites a movable part in the sliding direction in an angular velocity sensor, the Coriolis force caused by the angular velocity acts in a direction perpendicular to the sliding direction, so the vibration caused by the angular velocity and the electrode structure The resulting vibrations are superimposed and the detection accuracy is reduced.

  In this specification, the technique which solves said subject is provided. The present specification provides a technology capable of suppressing the excitation of the movable part to the other axis in the MEMS device capable of exciting the movable part by the counter electrode pair and the slide electrode.

  The MEMS device disclosed in this specification includes a substrate, a first movable portion elastically supported with respect to the substrate, a first counter electrode pair disposed at the same potential and facing each other, and a first The first electrode structure that is movable in a predetermined sliding direction with respect to the counter electrode pair and that includes the first slide electrode disposed between the first counter electrode pair is disposed at the same potential and opposite to each other. And a second electrode structure that is movable in the sliding direction with respect to the second counter electrode pair and includes a second slide electrode disposed between the second counter electrode pair. . One of the first counter electrode pair and the first slide electrode is immovable in the sliding direction with respect to the first movable part. One of the second counter electrode pair and the second slide electrode is immovable in the sliding direction with respect to the first movable part. With respect to the sliding direction, the first slide electrode is arranged offset with respect to the first counter electrode pair, and the second slide electrode is arranged without offset with respect to the second counter electrode pair.

  In the MEMS device described above, vibration in the sliding direction of the first movable portion can be started by applying a starting voltage to the first electrode structure in which the first slide electrode is offset with respect to the first counter electrode pair. . When the first movable portion starts to vibrate in the slide direction, the second slide electrode is displaced in the slide direction with respect to the second counter electrode pair in the second electrode structure. By applying an excitation voltage to the second electrode structure in accordance with the timing at which this displacement occurs, vibrations in the sliding direction of the first movable part can be excited to excite the first movable part in the sliding direction. it can. In the above MEMS device, since the second slide electrode does not need to be arranged offset with respect to the second counter electrode pair, the second slide electrode does not tilt with respect to the second counter electrode pair. When an excitation voltage is applied to the two-electrode structure, the first movable part is not excited in a direction orthogonal to the sliding direction. It is possible to suppress the first movable part from being excited in the other axis direction. In the above MEMS device, since the first slide electrode is offset with respect to the first counter electrode pair, when the activation electrode is applied to the first electrode structure, the first movable portion moves in the slide direction. There is a case where vibration is slightly started in a direction orthogonal to the direction. However, since this vibration is quickly attenuated and is not excited thereafter, it does not significantly affect the operation of the MEMS device.

FIG. 3 is a cross-sectional view of the MEMS device 2 according to the first embodiment. The longitudinal cross-sectional view seen in the II-II cross section of the MEMS apparatus 2 of Example 1. FIG. The longitudinal cross-sectional view seen in the III-III cross section of the MEMS apparatus 2 of Example 1. FIG. FIG. 3 is a cross-sectional view of a main part for explaining the operation of the MEMS device 2 according to the first embodiment. FIG. 3 is a cross-sectional view of a main part for explaining the operation of the MEMS device 2 according to the first embodiment. FIG. 3 is a cross-sectional view of a main part for explaining the operation of the MEMS device 2 according to the first embodiment. FIG. 6 is a cross-sectional view of the MEMS device 102 according to the second embodiment. The longitudinal cross-sectional view seen in the VIII-VIII cross section of the MEMS apparatus 102 of Example 2. FIG. FIG. 10 is a longitudinal sectional view for explaining a manufacturing process for the MEMS device 102 according to the second embodiment. FIG. 10 is a longitudinal sectional view for explaining a manufacturing process for the MEMS device 102 according to the second embodiment. FIG. 10 is a longitudinal sectional view for explaining a manufacturing process for the MEMS device 102 according to the second embodiment. FIG. 10 is a longitudinal sectional view for explaining a manufacturing process for the MEMS device 102 according to the second embodiment. FIG. 10 is a longitudinal sectional view for explaining a manufacturing process for the MEMS device 102 according to the second embodiment. FIG. 10 is a longitudinal sectional view for explaining a manufacturing process for the MEMS device 102 according to the second embodiment. FIG. 10 is a longitudinal sectional view for explaining a manufacturing process for the MEMS device 102 according to the second embodiment. FIG. 10 is a longitudinal sectional view for explaining a manufacturing process for the MEMS device 102 according to the second embodiment. FIG. 10 is a longitudinal sectional view for explaining a manufacturing process for the MEMS device 102 according to the second embodiment. FIG. 10 is a longitudinal sectional view for explaining a manufacturing process for the MEMS device 102 according to the second embodiment. FIG. 10 is a longitudinal sectional view for explaining a manufacturing process for the MEMS device 102 according to the second embodiment. FIG. 4 is a cross-sectional view of a MEMS device 402 according to a third embodiment.

  The MEMS device disclosed in this specification is configured to further include a pressing member that presses a part of the first electrode structure to offset the first slide electrode with respect to the first counter electrode pair in the sliding direction. can do.

  In the MEMS device, the first slide electrode is formed in a shape not offset with respect to the first counter electrode pair, and then the first slide electrode is offset with respect to the first counter electrode pair by the pressing member. it can.

  The MEMS device disclosed in this specification can be configured such that the substrate is a laminated substrate, and the first electrode structure and the second electrode structure are formed in the same layer.

  The MEMS device can be manufactured by forming the first electrode structure and the second electrode structure in the same layer, and then offsetting the first slide electrode with respect to the first counter electrode pair by the pressing member. it can. The manufacturing process can be simplified.

  The MEMS device disclosed in this specification further includes a second movable portion that is elastically supported with respect to the substrate, and the other of the second counter electrode pair and the second slide electrode is the second movable portion. On the other hand, it can be configured to be immovable in the sliding direction.

  In the MEMS device described above, the first movable portion starts to vibrate in the sliding direction by applying a starting voltage to the first electrode structure. Thereafter, when an excitation voltage is applied to the second electrode structure, the first movable portion and the second movable portion are excited in opposite phases in the sliding direction. By setting it as such a structure, the vibration leak to the exterior can be suppressed. The Q value of excitation is improved, and a large vibration can be excited with a small excitation voltage.

Example 1
The MEMS device 2 of this embodiment shown in FIGS. 1 to 3 is formed on a laminated substrate 8 in which a first substrate 4 and a second substrate 6 are laminated. The first substrate 4 includes an SOI (Silicon) in which a silicon layer 10 made of single crystal silicon, a silicon oxide layer 12 made of silicon oxide, and a conductive silicon layer 14 made of single crystal silicon provided with conductivity are sequentially stacked. on Insulator) substrate. The second substrate 6 is a silicon substrate made of single crystal silicon. In the following description, the lamination direction of the laminated substrate 8 is defined as the Z direction, and the in-plane directions of the laminated substrate 8 are defined as the X direction and the Y direction. In the following description, the positive direction in the Z direction is referred to as the upward direction, and the negative direction in the Z direction is referred to as the downward direction. In the MEMS device 2 of the present embodiment, the second substrate 6 is laminated above the first substrate 4. In the MEMS device 2 of this embodiment, the silicon oxide layer 12 is stacked above the silicon layer 10, and the conductive silicon layer 14 is stacked above the silicon oxide layer 12.

  As shown in FIG. 1, the conductive silicon layer 14 is etched into a frame portion 16, a mass support portion 18, a straight beam portion 20, a mass portion 22, a first movable electrode portion 24, and a second movable electrode. The electrode portion 26, the first fixed electrode portion 28, the first fixed electrode support portion 30, the second fixed electrode portion 32, and the second fixed electrode support portion 34 are formed. The mass support portion 18, the straight beam portion 20, the mass portion 22, the first movable electrode portion 24, and the second movable electrode portion 26 are integrally formed without a joint, and these are maintained at the same potential. ing. The first fixed electrode portion 28 and the first fixed electrode support portion 30 are integrally formed without a seam, and these are maintained at the same potential. The second fixed electrode portion 32 and the second fixed electrode support portion 34 are integrally formed without a seam, and these are maintained at the same potential.

  The mass portion 22 is formed in a rectangular shape when the conductive silicon layer 14 is viewed from above. As shown in FIGS. 2 and 3, the silicon oxide layer 12 below the mass portion 22 is removed by etching. As shown in FIG. 1, two straight beam portions 20 are connected to both ends of the mass portion 22 in the negative X direction and in the Y direction. The two straight beam portions 20 each extend along the X direction, and connect between the mass portion 22 and the mass support portion 18. The two straight beam portions 20 are each formed in a shape having high rigidity in the X direction and Y direction and low rigidity in the Z direction. The silicon oxide layer 12 below the two straight beam portions 20 is removed by etching. The mass support portion 18 is formed in a rectangular shape when the conductive silicon layer 14 is viewed from above. As shown in FIGS. 2 and 3, the mass support portion 18 is fixed to the silicon layer 10 via the lower silicon oxide layer 12.

  As shown in FIG. 1, a first movable electrode portion 24 and a second movable electrode portion 26 are provided at the end of the mass portion 22 in the positive X direction. The first movable electrode portion 24 includes a support piece 24a extending from the mass portion 22 along the X direction, and an electrode piece 24b extending from the support piece 24a along the Y direction. The silicon oxide layer 12 below the first movable electrode portion 24 is removed by etching. The second movable electrode portion 26 includes a support piece 26a extending from the mass portion 22 along the X direction and an electrode piece 26b extending from the support piece 26a along the Y direction. The silicon oxide layer 12 below the second movable electrode portion 26 is removed by etching.

  The first fixed electrode portion 28 includes a support plate 28a extending from the first fixed electrode support portion 30 along the X direction, a support piece 28b extending from the support plate 28a along the X direction, and the support piece 28b extending along the Y direction. The electrode piece 28c is extended. The electrode piece 28 c is disposed between the electrode piece 24 b of the first movable electrode portion 24 and the mass portion 22. The silicon oxide layer 12 below the first fixed electrode portion 28 is removed by etching. As shown in FIG. 2, the first fixed electrode support 30 is fixed to the silicon layer 10 via the lower silicon oxide layer 12.

  The electrode piece 24b and the mass portion 22 of the first movable electrode portion 24 have the same potential as each other, and constitute a counter electrode pair that is disposed to face each other. Further, the electrode piece 28c of the first fixed electrode portion 28 is movable in the sliding direction with respect to the electrode piece 24b and the mass portion 22 of the first movable electrode portion 24, with the Z direction as the sliding direction. A slide electrode disposed between the electrode piece 24 b of the electrode portion 24 and the mass portion 22 is configured. The electrode piece 24b, the mass part 22, and the electrode piece 28c of the first fixed electrode part 28 of the first movable electrode part 24 constitute an electrode structure including a counter electrode pair and a slide electrode.

  As shown in FIG. 1, the second fixed electrode portion 32 includes a support plate 32 a extending from the second fixed electrode support portion 34 along the X direction, a support piece 32 b extending from the support plate 32 a along the X direction, and a support An electrode piece 32c extending from the piece 32b along the Y direction is provided. The electrode piece 32 c is a slide electrode that is disposed between the electrode piece 26 b of the second movable electrode portion 26 that is a counter electrode and the mass portion 22. The silicon oxide layer 12 below the second fixed electrode portion 32 is removed by etching. As shown in FIG. 3, the second fixed electrode support portion 34 is fixed to the silicon layer 10 via the lower silicon oxide layer 12.

  The electrode piece 26b and the mass portion 22 of the second movable electrode portion 26 are at the same potential as each other, and constitute a counter electrode pair disposed to face each other. The electrode piece 32c of the second fixed electrode portion 32 is movable in the sliding direction with respect to the electrode piece 26b of the second movable electrode portion 26 and the mass portion 22 with the Z direction as the sliding direction, and is second movable. A slide electrode disposed between the electrode piece 26b of the electrode portion 26 and the mass portion 22 is configured. The electrode piece 26b, the mass part 22, and the electrode piece 32c of the second fixed electrode part 32 of the second movable electrode part 26 constitute an electrode structure including a counter electrode pair and a slide electrode.

  As shown in FIG. 1, when the conductive silicon layer 14 is viewed from above, the frame portion 16 has a mass support portion 18, a straight beam portion 20, a mass portion 22, a first movable electrode portion 24, In the shape of a rectangular frame that covers the periphery of the second movable electrode portion 26, the first fixed electrode portion 28, the first fixed electrode support portion 30, the second fixed electrode portion 32, and the second fixed electrode support portion 34. Is formed. As shown in FIGS. 2 and 3, the frame portion 16 is fixed to the silicon layer 10 via the lower silicon oxide layer 12.

  As shown in FIGS. 2 and 3, the second substrate 6 includes a recess 36 on the lower surface. When the MEMS device 2 is viewed in plan view from above, the concave portion 36 includes the mass support portion 18, the straight beam portion 20, the mass portion 22, the first movable electrode portion 24, the second movable electrode portion 26, and the like of the conductive silicon layer 14. The support piece 28b and the electrode piece 28c of the first fixed electrode portion 28 and the support piece 32b and the electrode piece 32c of the second fixed electrode portion 32 are formed. The second substrate 6 is bonded to the frame portion 16 of the conductive silicon layer 14.

  On the lower surface of the second substrate 6, a pressing member 38 is formed at a location corresponding to the support plate 28 a of the first fixed electrode portion 28 of the conductive silicon layer 14. The pressing member 38 is formed by laminating, for example, polysilicon or metal on the lower surface of the second substrate 6. When the second substrate 6 is joined to the first substrate 4, the pressing member 38 pushes down the support plate 28a of the first fixed electrode portion 28, so that the electrode piece 28c of the first fixed electrode portion 28 is also displaced downward. To do. As a result, the electrode pieces 28 c of the first fixed electrode portion 28 are arranged offset in the Z direction with respect to the mass pieces 22 and the electrode pieces 24 b of the first movable electrode portion 24. Note that the electrode pieces 32 c of the second fixed electrode portion 32 are arranged without being offset in the Z direction with respect to the mass pieces 22 and the electrode pieces 26 b of the second movable electrode portion 26.

  As shown in FIGS. 2 and 3, bumps 40, 42 and 44 are provided on the lower surface of the silicon layer 10. The bump 40 is electrically connected to the mass support portion 18 of the conductive silicon layer 14 through the through electrode 46 penetrating the silicon layer 10 and the silicon oxide layer 12. As shown in FIG. 2, the bump 42 is electrically connected to the first fixed electrode support portion 30 of the conductive silicon layer 14 through the through electrode 48 that penetrates the silicon layer 10 and the silicon oxide layer 12. As shown in FIG. 3, the bump 44 is electrically connected to the second fixed electrode support portion 34 of the conductive silicon layer 14 through the through electrode 50 that penetrates the silicon layer 10 and the silicon oxide layer 12.

  As shown in FIG. 1, the MEMS device 2 is used by being connected to an activation circuit 52 and an AC voltage source 54. The activation circuit 52 applies an activation voltage between the mass support portion 18 and the first fixed electrode support portion 30 via the bump 40 and the bump 42 illustrated in FIG. 2. The starting voltage is, for example, a pulse voltage having a predetermined magnitude. The AC voltage source 54 applies an excitation voltage between the mass support portion 18 and the second fixed electrode support portion 34 via the bumps 40 and the bumps 44 shown in FIG. The excitation voltage is, for example, a sinusoidal voltage having a predetermined amplitude.

  The operation of the MEMS device 2 will be described. 4 shows a state in which the mass portion 22 is not displaced relative to the mass support portion 18. FIG. 4A shows the mass portion 22, the electrode piece 24b of the first movable electrode portion 24, and the first piece. 4 shows the positional relationship of the electrode piece 28c of the first fixed electrode portion 28. FIG. 4B shows the electrode piece 26b of the mass portion 22, the second movable electrode portion 26, and the electrode piece 32c of the second fixed electrode portion 32. The positional relationship is shown. From this state, when the starting circuit 52 applies a starting voltage to the MEMS device 2, the mass part 22, the electrode piece 24 b of the first movable electrode part 24, and the electrode piece of the first fixed electrode part 28 shown in FIG. An electrostatic attractive force acts between 28c, and a downward force acts on the mass portion 22 and the first movable electrode portion 24. As a result, the mass portion 22 is displaced downward with respect to the mass support portion 18. The mass portion 22 is supported by the mass support portion 18 via the linear beam portion 20 having elasticity in the Z direction, and thereafter vibrates in the Z direction with respect to the mass support portion 18.

  When the mass portion 22 is displaced downward with respect to the mass support portion 18, as shown in FIG. 5A, the mass portion 22 and the electrode piece 24 b of the first movable electrode portion 24 are moved to the first fixed electrode portion 28. As shown in FIG. 5B, the mass piece 22 and the electrode piece 26 b of the second movable electrode portion 26 are replaced with the electrode pieces of the second fixed electrode portion 32. It is displaced downward with respect to 32c. At this timing, when the AC voltage source 54 applies an excitation voltage to the MEMS device 2, an electrostatic attractive force is generated between the mass portion 22, the electrode piece 26 b of the second movable electrode portion 26, and the electrode piece 32 c of the second fixed electrode portion 32. Acts, and an upward force acts on the mass portion 22 and the second movable electrode portion 26. Thereby, the vibration in the Z direction with respect to the mass support portion 18 of the mass portion 22 is vibrated.

  When the mass portion 22 is displaced upward with respect to the mass support portion 18, as shown in FIG. 6A, the mass pieces 22 and the electrode pieces 24 b of the first movable electrode portion 24 are moved to the first fixed electrode portion 28. As shown in FIG. 6 (b), the mass piece 22 and the electrode piece 26 b of the second movable electrode portion 26 are displaced from the electrode piece 28 c of the second fixed electrode portion 32. It is displaced upward with respect to 32c. At this timing, when the AC voltage source 54 applies an excitation voltage to the MEMS device 2, an electrostatic attractive force is generated between the mass portion 22, the electrode piece 26 b of the second movable electrode portion 26, and the electrode piece 32 c of the second fixed electrode portion 32. Acts, and a downward force acts on the mass portion 22 and the second movable electrode portion 26. Thereby, the vibration in the Z direction with respect to the mass support portion 18 of the mass portion 22 is vibrated.

  As described above, the mass portion 22 is mass-excited by applying the excitation in the Z direction of the mass portion 22 started by application of the activation voltage from the activation circuit 52 by application of the excitation voltage from the AC voltage source 54. The support portion 18 continues to vibrate greatly. By bringing the frequency of the AC voltage source 54 close to the resonance frequency of the mass portion 22, the mass portion 22 can be vibrated greatly.

  As shown in FIG. 4A, FIG. 5A, and FIG. 6A, the electrode piece 28c of the first fixed electrode portion 28 is opposite to the mass piece 22 and the electrode piece 24b of the first movable electrode portion 24. Slightly inclined. For this reason, when applying the excitation voltage to the mass portion 22, the first movable electrode portion 24, and the first fixed electrode portion 28 to excite the mass portion 22, the mass portion 22 is not only excited in the Z direction, Also excited in the direction. On the other hand, as shown in FIGS. 4B, 5B, and 6B, the electrode piece 32c of the second fixed electrode portion 32 includes the mass portion 22 and the second movable electrode portion 26. It is not inclined with respect to the electrode piece 26b. For this reason, when an excitation voltage is applied to the mass portion 22, the second movable electrode portion 26, and the second fixed electrode portion 32 to excite the mass portion 22, the mass portion 22 is excited only in the Z direction. Therefore, in the MEMS device 2 according to the present embodiment, the mass portion 22 starts to vibrate by applying the activation voltage to the mass portion 22, the first movable electrode portion 24, and the first fixed electrode portion 28. The mass portion 22 is excited by applying an excitation voltage to the second movable electrode portion 26 and the second fixed electrode portion 32. Thereby, the mass portion 22 can be excited only in the Z direction. In the MEMS device 2 of the present embodiment, the mass portion 22 also vibrates slightly in the X direction by applying the activation voltage to the mass portion 22, the first movable electrode portion 24, and the first fixed electrode portion 28. However, since the vibration of the mass portion 22 in the X direction is quickly attenuated and is not excited thereafter, the operation of the mass portion 22 is not greatly affected.

(Example 2)
7 and 8 is formed on a laminated substrate 110 in which a first substrate 104, a second substrate 106, and a third substrate 108 are laminated. The first substrate 104 is a silicon substrate made of single crystal silicon. The second substrate 106 includes a silicon oxide layer 112 made of silicon oxide and a conductive silicon layer 114 made of single crystal silicon imparted with conductivity. The third substrate 108 includes a silicon oxide layer 116 made of silicon oxide and a silicon layer 118 made of single crystal silicon. In the following description, the stacking direction of the stacked substrate 110 is defined as the Z direction, and the in-plane directions of the stacked substrate 110 are defined as the X direction and the Y direction. In the following description, the positive direction in the Z direction is referred to as the upward direction, and the negative direction in the Z direction is referred to as the downward direction. In the MEMS device 102 of this embodiment, the second substrate 106 is stacked above the first substrate 104, and the third substrate 108 is stacked above the second substrate 106. In the MEMS device 102 of this embodiment, the silicon oxide layer 112 is stacked above the first substrate 104, and the conductive silicon layer 114 is stacked above the silicon oxide layer 112. A silicon oxide layer 116 is stacked above, and a silicon layer 118 is stacked above the silicon oxide layer 116.

  As shown in FIG. 7, the conductive silicon layer 114 is etched into a frame portion 120, mass support portions 122, 124, 126, and 128, folded beam portions 130, 132, 134, and 136, and a mass portion 138. , First movable electrode portions 140, 142, 144, 146, second movable electrode portions 148, 150, 152, 154, third movable electrode portions 156, 158, first fixed electrode portions 160, 162, 164, 166, first fixed electrode support portions 168, 170, 172, 174, second fixed electrode portions 176, 178, 180, 182; second fixed electrode support portions 184, 186, 188, 190; and third fixed Electrode portions 192 and 194 and third fixed electrode support portions 196 and 198 are formed. Mass support portions 122, 124, 126, 128, folded beam portions 130, 132, 134, 136, mass portions 138, first movable electrode portions 140, 142, 144, 146, second movable electrode portions 148, 150, 152, 154 and the third movable electrode portions 156, 158 are integrally formed without a joint, and these are maintained at the same potential. The first fixed electrode portion 160 and the corresponding first fixed electrode support portion 168 are integrally formed without a joint, and these are maintained at the same potential. The same applies to the first fixed electrode portions 162, 164, and 166 and the corresponding first fixed electrode support portions 170, 172, and 174. The second fixed electrode portion 176 and the corresponding second fixed electrode support portion 184 are integrally formed seamlessly, and these are maintained at the same potential. The same applies to the second fixed electrode portions 178, 180, and 182 and the corresponding second fixed electrode support portions 186, 188, and 190. The third fixed electrode portion 192 and the corresponding third fixed electrode support portion 196 are integrally formed without a joint, and these are maintained at the same potential. The same applies to the third fixed electrode portion 194 and the corresponding third fixed electrode support portion 198.

  The mass portion 138 is formed in a rectangular shape when the conductive silicon layer 114 is viewed from above. As shown in FIG. 8, the silicon oxide layer 112 below the mass portion 138 is removed by etching. As shown in FIG. 7, folded beam portions 130, 132, 134, 136 are connected to the squares of the mass portion 138. The folded beam portions 130, 132, 134, 136 are respectively a first straight portion extending from the mass portion 138 along the X direction, a folded portion extending from the end of the first straight portion along the Y direction, and a folded portion A second linear portion extending from the end portion along the X direction and connected to the mass support portions 122, 124, 126, and 128 is provided. The folded beam portions 130, 132, 134, and 136 are each formed in a shape having high rigidity in the X direction and low rigidity in the Y direction and Z direction. The silicon oxide layer 112 below the folded beam portions 130, 132, 134, and 136 is removed by etching. The mass support portions 122, 124, 126, and 128 are each formed in a rectangular shape when the conductive silicon layer 114 is viewed from above. The mass support portions 122, 124, 126, and 128 are each fixed to the first substrate 104 via the lower silicon oxide layer 112.

  As shown in FIG. 7, first movable electrode portions 140, 142, 144, and 146 are provided in the folded portions of the folded beam portions 130, 132, 134, and 136, respectively. The first movable electrode portions 140, 142, 144, and 146 include support pieces that extend from the folded beam portions 130, 132, 134, and 136 along the X direction, and electrode pieces that extend from the support piece along the Y direction. . As shown in FIG. 8, the silicon oxide layer 112 below the first movable electrode portions 140, 142, 144, and 146 is removed by etching.

  As shown in FIG. 7, second movable electrode portions 148, 150, 152, and 154 are provided at the ends of the mass portions 138 in the X direction. The second movable electrode portions 148, 150, 152, and 154 include a support piece that extends from the mass portion 138 along the X direction and an electrode piece that extends from the support piece along the Y direction. As shown in FIG. 8, the silicon oxide layer 112 below the second movable electrode portions 148, 150, 152, and 154 is removed by etching.

  As shown in FIG. 7, third movable electrode portions 156 and 158 are provided at the ends of the mass portions 138 in the Y direction. The third movable electrode portions 156 and 158 include a support piece extending from the mass portion 138 along the Y direction and an electrode piece extending from the support piece along the X direction. The silicon oxide layer 112 below the third movable electrode portions 156 and 158 is removed by etching.

  As shown in FIG. 7, the first fixed electrode portions 160, 162, 164, 166 include a support plate extending along the X direction from the first fixed electrode support portions 168, 170, 172, 174, and the X direction from the support plate. And an electrode piece extending along the Y direction from the support piece. The electrode pieces and the support plates of the first fixed electrode portions 160, 162, 164, and 166 have the same potential, and are arranged to face each other. Corresponding electrode pieces of the first movable electrode portions 140, 142, 144, and 146 are disposed between the electrode pieces of the first fixed electrode portions 160, 162, 164, and 166 and the support plate. As shown in FIG. 8, the silicon oxide layer 112 below the first fixed electrode portions 160, 162, 164, and 166 is removed by etching. The first fixed electrode support portions 168, 170, 172, and 174 are fixed to the first substrate 104 through the lower silicon oxide layer 112.

  The electrode piece and the support plate of the first fixed electrode portion 160 have the same potential as each other, and constitute a counter electrode pair disposed to face each other. In addition, the electrode piece of the first movable electrode part 140 is movable in the sliding direction with respect to the electrode piece of the first fixed electrode part 160 and the support plate, with the Z direction as the sliding direction, and the first fixed electrode part 160. The slide electrode disposed between the electrode piece and the support plate is configured. The electrode piece and support plate of the first fixed electrode part 160 and the electrode piece of the first movable electrode part 140 constitute an electrode structure including a counter electrode pair and a slide electrode. The same applies to the first fixed electrode portions 162, 164, and 166 and the corresponding first movable electrode portions 142, 144, and 146.

  As shown in FIG. 7, the second fixed electrode portions 176, 178, 180, and 182 include a support plate extending along the X direction from the second fixed electrode support portions 184, 186, 188, and 190, and the X direction from the support plate. And an electrode piece extending along the Y direction from the support piece. The electrode pieces and the support plates of the second fixed electrode portions 176, 178, 180, and 182 are each at the same potential and are arranged to face each other. Corresponding electrode pieces of the second movable electrode portions 148, 150, 152, and 154 are disposed between the electrode pieces of the second fixed electrode portions 176, 178, 180, and 182 and the support plate. As shown in FIG. 8, the silicon oxide layer 112 below the second fixed electrode portions 176, 178, 180, and 182 is removed by etching. The second fixed electrode support portions 184, 186, 188, and 190 are fixed to the first substrate 104 through the lower silicon oxide layer 112.

  The electrode pieces and the support plate of the second fixed electrode portion 176 are at the same potential as each other, and constitute a counter electrode pair disposed to face each other. Further, the electrode piece of the second movable electrode portion 148 is movable in the sliding direction with respect to the electrode piece of the second fixed electrode portion 176 and the support plate, with the Z direction as the sliding direction, and the second fixed electrode portion 176. The slide electrode disposed between the electrode piece and the support plate is configured. The electrode piece and the support plate of the second fixed electrode portion 176 and the electrode piece of the second movable electrode portion 148 constitute an electrode structure including a counter electrode pair and a slide electrode. The same applies to the second fixed electrode portions 178, 180, and 182 and the corresponding second movable electrode portions 150, 152, and 154.

  As shown in FIG. 7, the third fixed electrode portions 192 and 194 include a support piece extending along the Y direction from the third fixed electrode support portions 196 and 198, and an electrode piece extending along the X direction from the support piece. ing. The electrode pieces of the third fixed electrode portions 192 and 194 are respectively disposed so as to face the electrode pieces of the corresponding third movable electrode portions 156 and 158 in the Y direction. The silicon oxide layer 112 below the third fixed electrode portions 192 and 194 is removed by etching. The third fixed electrode support portions 196 and 198 are fixed to the first substrate 104 through the lower silicon oxide layer 112.

  As shown in FIG. 7, the frame part 120 includes mass support parts 122, 124, 126, 128, folded beam parts 130, 132, 134, 136, a mass part 138, first movable electrode parts 140, 142, 144, 146, second movable electrode portions 148, 150, 152, 154, third movable electrode portions 156, 158, first fixed electrode portions 160, 162, 164, 166, and first fixed electrode support portion 168. , 170, 172, 174, second fixed electrode portions 176, 178, 180, 182, second fixed electrode support portions 184, 186, 188, 190, third fixed electrode portions 192, 194, and third fixed It is formed in a rectangular frame shape that covers the periphery of the electrode support portions 196 and 198. As shown in FIG. 8, the frame portion 120 is fixed to the first substrate 104 via the lower silicon oxide layer 112.

  As shown in FIG. 8, the first substrate 104 has a recess 200 on the upper surface. When the MEMS device 102 is viewed from above, the concave portion 200 includes the folded beam portions 130, 132, 134, and 136, the mass portion 138, and the first movable electrode portions 140, 142, and 144 of the conductive silicon layer 114. 146, the second movable electrode portions 148, 150, 152, 154, the third movable electrode portions 156, 158, the support pieces and electrode pieces of the first fixed electrode portions 160, 162, 164, 166, and the second fixed It is formed in a range including the support pieces and electrode pieces of the electrode portions 176, 178, 180, and 182 and the support pieces and electrode pieces of the third fixed electrode portions 192 and 194.

  As shown in FIG. 8, the silicon layer 118 of the third substrate 108 has a recess 202 on the lower surface. The concave portion 202 is formed in a range that is substantially the same shape as the concave portion 200 of the first substrate 104 when the MEMS device 102 is viewed from above. The silicon oxide layer 116 of the third substrate 108 includes the folded beam portions 130, 132, 134, and 136, the mass portion 138, the first movable electrode portions 140, 142, 144, and 146 of the conductive silicon layer 114, the second The movable electrode portions 148, 150, 152, 154, the third movable electrode portions 156, 158, the support pieces and electrode pieces of the first fixed electrode portions 160, 162, 164, 166, and the second fixed electrode portions 176, 178 , 180, 182 and the range corresponding to the third fixed electrode portions 192, 194 are removed by etching. The third substrate 108 is bonded to the second substrate 106 by bonding the silicon oxide layer 116 to the frame portion 120 of the conductive silicon layer 114 of the second substrate 106.

  On the lower surface of the silicon oxide layer 116 of the third substrate 108, pressing members 204, 206, 208, and 210 are provided at locations corresponding to the support plates of the first fixed electrode portions 160, 162, 164, and 166 of the conductive silicon layer 114. Is formed. The pressing members 204, 206, 208, and 210 are formed by laminating, for example, polysilicon or metal on the lower surface of the silicon oxide layer 116. When the third substrate 108 is joined to the second substrate 106, the pressing members 204, 206, 208, 210 push down the support plates of the first fixed electrode portions 160, 162, 164, 166 downward, so that the first fixing The electrode pieces of the electrode portions 160, 162, 164, and 166 are also displaced downward. Accordingly, the electrode pieces of the first movable electrode portions 140, 142, 144, and 146 are arranged offset in the Z direction with respect to the electrode pieces and the support plate of the first fixed electrode portions 160, 162, 164, and 166. The The electrode pieces of the second movable electrode portions 148, 150, 152, 154 are arranged without being offset in the Z direction with respect to the electrode pieces of the second fixed electrode portions 176, 178, 180, 182 and the support plate. The

  As shown in FIG. 8, the first fixed electrode support portions 168, 170, 172, 174 pass through the first substrate 104 and the through electrodes 212, 214, 216, 218 penetrating the silicon oxide layer 112. The bumps 220, 222, 224, and 226 formed on the lower surface of 104 are electrically connected. The second fixed electrode support portions 184, 186, 188, and 190 are formed on the lower surface of the first substrate 104 via the through electrodes 228, 230, 232, and 234 that penetrate the first substrate 104 and the silicon oxide layer 112. The bumps 236, 238, 240, and 242 are electrically connected. Although not shown, the third fixed electrode support portions 196 and 198 are electrically connected to the bumps formed on the lower surface of the first substrate 104 through the through electrodes penetrating the first substrate 104 and the silicon oxide layer 112. ing. Although not shown, the mass support part 122 is electrically connected to a bump formed on the lower surface of the first substrate 104 through a through electrode penetrating the first substrate 104 and the silicon oxide layer 112.

  Although not shown, the MEMS device 102 is used by being connected to an activation circuit, an AC voltage source, and a capacitance detection circuit. The activation circuit applies an activation voltage between the mass support part 122 and the first fixed electrode support parts 168, 170, 172, 174. The starting voltage is, for example, a pulse voltage having a predetermined magnitude. The AC voltage source applies an excitation voltage between the mass support part 122 and the second fixed electrode support parts 184, 186, 188 and 190. The excitation voltage is, for example, a sinusoidal voltage having a predetermined amplitude. The capacitance detection circuit detects the difference between the capacitance between the mass support portion 122 and the third fixed electrode support portion 196 and the capacitance between the mass support portion 122 and the third fixed electrode support portion 198.

  The operation of the MEMS device 102 will be described. Similar to the MEMS device 2 of the first embodiment, when the activation circuit applies the activation voltage to the MEMS device 102, the electrode pieces of the first fixed electrode portions 160, 162, 164, and 166, and the first movable electrode portions 140, 142, An electrostatic attractive force acts between the electrode pieces 144 and 146 and the support plates of the first fixed electrode portions 160, 162, 164, and 166, and a downward force acts on the first movable electrode portions 140, 142, 144, and 146. . As a result, the mass portion 138 starts to vibrate in the Z direction. Then, the AC voltage source applies an excitation voltage to the MEMS device 102, whereby the electrode pieces of the second fixed electrode portions 176, 178, 180, and 182 and the electrode pieces of the second movable electrode portions 148, 150, 152, and 154 are obtained. And electrostatic attraction acts between the support plates of the second fixed electrode portions 176, 178, 180, 182 and forces periodically act upward and downward on the second movable electrode portions 148, 150, 152, 154, The vibration in the Z direction of the mass portion 138 is excited. As a result, the mass portion 138 is excited in the Z direction.

  When an angular velocity around the X-axis acts on the MEMS device 102 in a state where the mass portion 138 vibrates in the Z direction, a Coriolis force in the Y direction acts on the mass portion 138, and the mass portion 138 also vibrates in the Y direction. To do. At this time, the amplitude of the vibration in the Y direction of the mass portion 138 increases as the angular velocity around the X axis acting on the MEMS device 102 increases. As the mass portion 138 vibrates in the Y direction, the capacitance between the third movable electrode portions 156 and 158 and the third fixed electrode portions 192 and 194 changes. The amount of change in capacitance at this time increases as the amplitude of vibration in the Y direction of the mass portion 138 increases. Therefore, the amount of change in capacitance between the mass support unit 122 and the third fixed electrode support unit 196 and the amount of change in capacitance between the mass support unit 122 and the third fixed electrode support unit 198 are detected. Thus, the angular velocity around the X axis acting on the MEMS device 102 can be detected. Note that the MEMS device 102 detects a difference between the capacitance between the mass support portion 122 and the third fixed electrode support portion 196 and the capacitance between the mass support portion 122 and the third fixed electrode support portion 198. Thus, the angular velocity around the X axis acting on the MEMS device 102 can be detected with high accuracy.

  Below, the manufacturing method of the MEMS apparatus 102 is demonstrated. First, as shown in FIG. 9, a second substrate 106 including a conductive silicon layer 114 made of single crystal silicon imparted with conductivity is prepared. Then, the second substrate 106 is thermally oxidized to form silicon oxide layers 302 and 112 on the upper surface and the lower surface, respectively.

  Next, as shown in FIG. 10, the silicon oxide layer 302 on the upper surface of the second substrate 106 and a part of the silicon oxide layer 112 on the lower surface are removed by etching.

  Next, as shown in FIG. 11, a first substrate 104 made of single crystal silicon is prepared.

  Next, as shown in FIG. 12, a part of the upper surface of the first substrate 104 is removed by etching. Thereby, the recess 200 is formed.

  Next, as shown in FIG. 13, the silicon oxide layer 112 on the lower surface of the second substrate 106 is bonded to the upper surface of the first substrate 104.

  Next, as shown in FIG. 14, the conductive silicon layer 114 of the second substrate 106 is selectively removed by etching. Accordingly, the frame portion 120, the mass support portions 122, 124, 126, and 128, the folded beam portions 130, 132, 134, and 136, the mass portion 138, and the first movable electrode portions 140, 142, 144, and 146, , Second movable electrode portions 148, 150, 152, 154, third movable electrode portions 156, 158, first fixed electrode portions 160, 162, 164, 166, and first fixed electrode support portions 168, 170, 172. 174, second fixed electrode portions 176, 178, 180, 182; second fixed electrode support portions 184, 186, 188, 190; third fixed electrode portions 192, 194; and third fixed electrode support portion 196. 198 is formed.

  Next, as shown in FIG. 15, through electrodes 212, 214, 216, 218, 228, 230, 232, 234 and the like, and bumps 220, 222, 224, 226, 236, 238, 240, 242 and the like are formed.

  Next, as shown in FIG. 16, a third substrate 108 including a silicon layer 118 made of single crystal silicon is prepared. Then, a silicon oxide layer 116 is formed on the lower surface of the silicon layer 118. Then, a polysilicon layer 304 made of polysilicon is formed on the lower surface of the silicon oxide layer 116.

  Next, as shown in FIG. 17, the polysilicon layer 304 is selectively removed by etching. Thereby, the pressing members 204, 206, 208, and 210 are formed.

  Next, as shown in FIG. 18, the silicon oxide layer 116 is selectively removed by etching.

  Next, as shown in FIG. 19, the lower surface of the silicon layer 118 is selectively removed by etching. Thereby, the recess 202 is formed.

  Next, as shown in FIG. 8, the lower surface of the silicon oxide layer 116 of the third substrate 108 is bonded to the upper surface of the conductive silicon layer 114 of the second substrate 106. At this time, the first fixed electrode portions 160, 162, 164, 166 are pushed downward by the pressing members 204, 206, 208, 210, and the electrode pieces of the first movable electrode portions 140, 142, 144, 146 are The first fixed electrode portions 160, 162, 164, and 166 are arranged with an offset in the Z direction with respect to the electrode pieces and the support plate. The MEMS device 102 is manufactured by the above manufacturing process.

(Example 3)
Similar to the MEMS device 102 of the second embodiment, the MEMS device 402 of the present embodiment is formed on the laminated substrate 110 in which the first substrate 104, the second substrate 106, and the third substrate 108 are laminated. The first substrate 104 is a silicon substrate made of single crystal silicon. The second substrate 106 includes a silicon oxide layer 112 made of silicon oxide and a conductive silicon layer 114 made of single crystal silicon imparted with conductivity. The third substrate 108 includes a silicon oxide layer 116 made of silicon oxide and a silicon layer 118 made of single crystal silicon. Below, the structure of the 2nd board | substrate 106 in the MEMS apparatus 402 of a present Example is demonstrated in detail.

  As shown in FIG. 20, in the MEMS device 402 according to the present embodiment, the inner silicon support portions 404, 406, 408, 410 and the inner folded beam portions 412, 414, 416, 418 are etched into the conductive silicon layer 114 by etching. , Inner mass portion 420, inner excitation electrode portions 422, 424, first movable detection electrode portions 426, 428, outer mass support portions 430, 432, 434, 436, outer folded beam portions 438, 440, 442, 444, outer mass portion 446, outer excitation electrode portions 448 and 450, movable activation electrode portions 452 and 454, second movable detection electrode portions 456 and 458, third movable detection electrode portions 460 and 462, and 1 fixed detection electrode unit 464, 466, first fixed detection electrode support unit 468, 470, fixed activation electrode unit 472, 474, and fixed activation electrode support unit 476 478, second fixed detection electrode portions 480, 482, second fixed detection electrode support portions 484, 486, third fixed detection electrode portions 488, 490, third fixed detection electrode support portions 492, 494, a frame A portion 496 is formed. Inner mass support portions 404, 406, 408, 410, inner folded beam portions 412, 414, 416, 418, inner mass portion 420, inner excitation electrode portions 422, 424, and first movable detection electrode portions 426, 428. Are integrally formed without a seam, and these are maintained at the same potential. Outer mass support portions 430, 432, 434, 436, outer folded beam portions 438, 440, 442, 444, outer mass portions 446, outer excitation electrode portions 448, 450, movable activation electrode portions 452, 454, The second movable detection electrode portions 456 and 458 and the third movable detection electrode portions 460 and 462 are integrally formed without a joint, and these are maintained at the same potential. The first fixed detection electrode portions 464 and 466 and the corresponding first fixed detection electrode support portions 468 and 470 are integrally formed seamlessly, and are maintained at the same potential. The fixed starting electrode portions 472 and 474 and the corresponding fixed starting electrode support portions 476 and 478 are integrally formed with no joints, and are maintained at the same potential. The second fixed detection electrode portions 480 and 482 and the corresponding second fixed detection electrode support portions 484 and 486 are integrally formed seamlessly, and are maintained at the same potential. The third fixed detection electrode portions 488 and 490 and the corresponding third fixed detection electrode support portions 492 and 494 are integrally formed seamlessly, and are maintained at the same potential.

  The inner mass portion 420 is formed in a rectangular shape when the conductive silicon layer 114 is viewed from above. The silicon oxide layer 112 below the inner mass portion 420 is removed by etching. Inner folded beam portions 412, 414, 416, and 418 are connected to the squares of the inner mass portion 420. The inner folded beam portions 412, 414, 416, and 418, respectively, are a first straight portion extending from the inner mass portion 420 along the Y direction, a folded portion extending from the end of the first straight portion along the XY direction, and a folded portion. A second linear portion extending from the end of the portion along the Y direction and connected to the inner mass support portions 404, 406, 408, 410. The inner folded beam portions 412, 414, 416, and 418 are each formed in a shape having high rigidity in the X direction and low rigidity in the Y direction and Z direction. The silicon oxide layer 112 below the inner folded beam portions 412, 414, 416, and 418 is removed by etching. The inner mass support portions 404, 406, 408, 410 are each formed in a square shape when the conductive silicon layer 114 is viewed from above. The inner mass support portions 404, 406, 408, 410 are each fixed to the first substrate 104 via the lower silicon oxide layer 112.

  Inner excitation electrode portions 422 and 424 are provided at end portions of the inner mass portion 420 in the X direction. The inner excitation electrode portions 422 and 424 include a support piece extending from the inner mass portion 420 along the X direction and an electrode piece extending from the support piece along the Y direction. The silicon oxide layer 112 below the inner excitation electrode portions 422 and 424 is removed by etching.

  First movable detection electrode portions 426 and 428 are provided at the end of the inner mass portion 420 in the Y direction. The first movable detection electrode portions 426 and 428 include a support piece extending from the inner mass portion 420 along the Y direction and an electrode piece extending from the support piece along the X direction. The silicon oxide layer 112 below the first movable detection electrode portions 426 and 428 is removed by etching.

  The first fixed detection electrode portions 464 and 466 include a support piece extending along the Y direction from the first fixed detection electrode support portions 468 and 470 and an electrode piece extending along the X direction from the support piece. The electrode pieces of the first fixed detection electrode portions 464 and 466 are arranged so as to face the corresponding electrode pieces of the first movable detection electrode portions 426 and 428 in the Y direction. The silicon oxide layer 112 below the first fixed detection electrode portions 464 and 466 is removed by etching. Further, the first fixed detection electrode support portions 468 and 470 are fixed to the first substrate 104 through the lower silicon oxide layer 112.

  The outer mass portion 446 includes the inner mass support portions 404, 406, 408, 410, the inner folded beam portions 412, 414, 416, 418, and the inner mass portion 420 when the conductive silicon layer 114 is viewed from above. The inner excitation electrode portions 422 and 424 and the first movable detection electrode portions 426 and 428 are formed in a rectangular frame shape. The silicon oxide layer 112 below the outer mass portion 446 has been removed by etching. Outer folded beam portions 438, 440, 442, and 444 are connected to the outer squares of the outer mass portion 446. The outer folded beam portions 438, 440, 442, and 444 are respectively a first straight portion that extends from the outer mass portion 446 along the Y direction, a folded portion that extends from the end of the first straight portion along the X direction, and a folded portion. A second linear portion extending from the end of the portion along the Y direction and connected to the outer mass support portions 430, 432, 434, 436. The outer folded beam portions 438, 440, 442, and 444 are each formed into a shape that has high rigidity in the Y direction and low rigidity in the X direction and Z direction. The silicon oxide layer 112 below the outer folded beam portions 438, 440, 442, 444 is removed by etching. The outer mass support portions 430, 432, 434, and 436 are each formed in a square shape when the conductive silicon layer 114 is viewed from above. The outer mass support portions 430, 432, 434, and 436 are each fixed to the first substrate 104 via the lower silicon oxide layer 112.

  Outside excitation electrode portions 448 and 450 are provided inside the outside mass portion 446. The outer excitation electrode portions 448 and 450 include a support piece extending along the X direction from the outer mass portion 446 and an electrode piece extending along the Y direction from the support piece. The electrode pieces of the outer mass portion 446 and the outer excitation electrode portion 448 are at the same potential and are disposed to face each other. Between the electrode pieces of the outer mass portion 446 and the outer excitation electrode portion 448, the electrode pieces of the inner excitation electrode portion 422 are arranged. The electrode pieces of the outer mass portion 446 and the outer excitation electrode portion 450 are at the same potential and are disposed to face each other. Between the electrode pieces of the outer mass portion 446 and the outer excitation electrode portion 450, the electrode pieces of the inner excitation electrode portion 424 are arranged. The silicon oxide layer 112 below the outer excitation electrode portions 448 and 450 is removed by etching.

  The electrode pieces of the outer mass portion 446 and the outer excitation electrode portion 448 have the same potential as each other, and constitute a counter electrode pair that is disposed to face each other. Further, the electrode pieces of the inner excitation electrode portion 422 are movable in the sliding direction with respect to the electrode pieces of the outer mass portion 446 and the outer excitation electrode portion 448, with the Z direction as the slide direction. A slide electrode disposed between the electrode pieces of the excitation electrode portion 448 is configured. The electrode pieces of the outer mass portion 446 and the outer excitation electrode portion 448 and the electrode pieces of the inner excitation electrode portion 422 constitute an electrode structure including a counter electrode pair and a slide electrode. The same applies to the outer mass portion 446, the outer excitation electrode portion 450, and the inner excitation electrode portion 424.

  Movable activation electrode portions 452 and 454 are provided at the end portion in the X direction outside the outer mass portion 446. The movable activation electrode portions 452 and 454 include a support piece extending along the X direction from the outer mass portion 446 and an electrode piece extending along the Y direction from the support piece. The silicon oxide layer 112 below the movable starting electrode portions 452 and 454 is removed by etching.

  Second movable detection electrode portions 456 and 458 are provided at end portions in the X direction outside the outer mass portion 446. The second movable detection electrode portions 456 and 458 include a support piece extending along the X direction from the outer mass portion 446 and an electrode piece extending along the Y direction from the support piece. The silicon oxide layer 112 below the second movable detection electrode portions 456 and 458 is removed by etching.

  Third movable detection electrode portions 460 and 462 are provided at end portions in the Y direction outside the outer mass portion 446. The third movable detection electrode portions 460 and 462 include a support piece extending along the Y direction from the outer mass portion 446 and an electrode piece extending along the X direction from the support piece. The silicon oxide layer 112 below the third movable detection electrode portions 460 and 462 is removed by etching.

  The fixed activation electrode portions 472 and 474 extend from the fixed activation electrode support portions 476 and 478 along the X direction, a support piece extending along the X direction from the support plate, and the support piece extending along the Y direction. An electrode piece is provided. The electrode pieces of the fixed activation electrode portions 472 and 474 and the support plate are at the same potential and are arranged to face each other. Corresponding electrode pieces of movable starting electrode portions 452 and 454 are arranged between the electrode pieces of fixed starting electrode portions 472 and 474 and the support plate. The silicon oxide layer 112 below the fixed activation electrode portions 472 and 474 is removed by etching. The fixed activation electrode support portions 476 and 478 are fixed to the first substrate 104 via the lower silicon oxide layer 112. The support plates of the fixed activation electrode portions 472 and 474 are pressed downward by the pressing members 498 and 500, respectively.

  The electrode piece and the support plate of the fixed activation electrode portion 472 are at the same potential, and constitute a counter electrode pair arranged to face each other. The electrode piece of the movable starting electrode portion 452 is movable in the sliding direction with respect to the electrode piece of the fixed starting electrode portion 472 and the support plate, with the Z direction as the sliding direction. And a slide electrode disposed between the support plate and the support plate. The electrode pieces and the support plate of the fixed starting electrode portion 472 and the electrode pieces of the movable starting electrode portion 452 constitute an electrode structure including a counter electrode pair and a slide electrode. The same applies to the fixed starting electrode portion 474 and the movable starting electrode portion 454.

  The second fixed detection electrode portions 480 and 482 include a support piece extending along the X direction from the second fixed detection electrode support portions 484 and 486 and an electrode piece extending along the Y direction from the support piece. The electrode pieces of the second fixed detection electrode portions 480 and 482 are arranged to face the electrode pieces of the second movable detection electrode portions 456 and 458 in the X direction. The silicon oxide layer 112 below the second fixed detection electrode portions 480 and 482 is removed by etching. The second fixed detection electrode support portions 484 and 486 are fixed to the first substrate 104 through the lower silicon oxide layer 112.

  The third fixed detection electrode portions 488 and 490 include a support piece extending along the Y direction from the third fixed detection electrode support portions 492 and 494 and an electrode piece extending along the X direction from the support piece. The electrode pieces of the third fixed detection electrode portions 488 and 490 are arranged so as to face the electrode pieces of the third movable detection electrode portions 460 and 462 in the Y direction. The silicon oxide layer 112 below the third fixed detection electrode portions 488 and 490 is removed by etching. The third fixed detection electrode support portions 492 and 494 are fixed to the first substrate 104 through the lower silicon oxide layer 112.

  The MEMS device 402 is formed such that the mass of the inner mass portion 420 and the mass of the outer mass portion 446 are substantially equal. The MEMS device 402 is formed such that the spring constant in the Z direction of the inner folded beam portions 412, 414, 416, and 418 is substantially equal to the spring constant in the Z direction of the outer folded beam portions 438, 440, 442, and 444. ing. Further, the MEMS device 402 is formed such that the Y-direction spring constant of the inner folded beam portions 412, 414, 416, and 418 and the X-direction spring constant of the outer folded beam portions 438, 440, 442, and 444 are substantially equal. ing. Accordingly, the resonance frequency of the vibration in the Z direction of the inner mass portion 420 is substantially equal to the resonance frequency of the outer mass portion 446 in the Z direction. Further, the resonance frequency of the vibration in the Y direction of the inner mass portion 420 is substantially equal to the resonance frequency of the vibration in the X direction of the outer mass portion 446.

  Although not shown, the first fixed detection electrode support portions 468 and 470, the fixed activation electrode support portions 476 and 478, the second fixed detection electrode support portions 484 and 486, the third fixed detection electrode portions 488 and 490, the inner mass The support portion 404 and the outer mass support portion 430 are electrically connected to bumps formed on the lower surface of the first substrate 104 through through electrodes that penetrate the first substrate 104 and the silicon oxide layer 112, respectively.

  Although not shown, the MEMS device 402 is used by being connected to an activation circuit, an AC voltage source, a first capacitance detection circuit, a second capacitance detection circuit, and a third capacitance detection circuit. The activation circuit applies an activation voltage between the outer mass support part 430 and the fixed activation electrode support parts 476 and 478. The starting voltage is, for example, a pulse voltage having a predetermined magnitude. The AC voltage source applies an excitation voltage between the inner mass support portion 404 and the outer mass support portion 430. The excitation voltage is, for example, a sinusoidal voltage having a predetermined amplitude. The first capacitance detection circuit includes a capacitance between the inner mass support portion 404 and the first fixed detection electrode support portion 468, and a capacitance between the inner mass support portion 404 and the first fixed detection electrode support portion 470. Detect the difference. The second capacitance detection circuit includes a capacitance between the outer mass support 430 and the second fixed detection electrode support 484 and a capacitance between the outer mass support 430 and the second fixed detection electrode support 486. Detect the difference. The third capacitance detection circuit calculates the capacitance between the outer mass support portion 430 and the third fixed detection electrode support portion 492 and the capacitance between the outer mass support portion 430 and the third fixed detection electrode support portion 494. Detect each.

  The operation of the MEMS device 402 will be described. Similar to the MEMS device 2 of the first embodiment and the MEMS device 102 of the second embodiment, when the starting circuit applies a starting voltage to the MEMS device 402, the electrode pieces of the fixed starting electrode portions 472 and 474, the movable starting electrode portion 452, An electrostatic attractive force acts between the electrode pieces of 454 and the support plates of the fixed activation electrode portions 472 and 474, a downward force acts on the movable activation electrode portions 452 and 454, and the outer mass portion 446 vibrates in the Z direction. Start. At this time, the outer mass portion 446 is displaced in the Z direction relative to the inner mass portion 420, so that the electrode pieces of the outer mass portion 446 and the outer excitation electrode portion 448 are displaced from the electrode pieces of the inner excitation electrode portion 422. Are relatively displaced. In accordance with this timing, the AC voltage source applies an excitation voltage to the MEMS device 402, whereby a force in the Z direction acts on the electrode pieces of the outer mass portion 446 and the outer excitation electrode portion 448, and the inner excitation electrode portion 422. As a reaction force in the Z direction acts on the electrode piece, the inner mass portion 420 and the outer mass portion 446 vibrate in the Z direction in opposite phases. At this time, since the mass of the inner mass portion 420 and the mass of the outer mass portion 446 are substantially equal, mutual vibrations are canceled and vibration leakage does not occur outside. Therefore, the vibration Q value can be extremely increased, and a large vibration in the Z direction can be excited with a small excitation voltage. Note that the vibration of the outer mass portion 446 in the Z direction at this time is determined by the third capacitance detection circuit, the capacitance between the outer mass support portion 430 and the third fixed detection electrode support portion 492, and the outer mass support. It is possible to monitor by detecting the electrostatic capacitance between the part 430 and the third fixed detection electrode support part 494, respectively.

  When an angular velocity around the X axis acts on the MEMS device 402 in a state where the inner mass portion 420 and the outer mass portion 446 are oscillating in the Z direction in opposite phases, the Y direction is applied to each of the inner mass portion 420 and the outer mass portion 446. Coriolis force acts. At this time, the outer mass portion 446 is supported by the outer folded beam portions 438, 440, 442, and 444 having high rigidity in the Y direction, and thus does not vibrate in the Y direction. On the other hand, since the inner mass portion 420 is supported by the inner folded beam portions 412, 414, 416, and 418 having low rigidity in the Y direction, it vibrates in the Y direction. At this time, the amplitude of the vibration in the Y direction of the inner mass portion 420 becomes larger as the angular velocity around the X axis acting on the MEMS device 402 becomes larger. As the inner mass portion 420 vibrates in the Y direction, the capacitance between the first movable detection electrode portions 426 and 428 and the corresponding first fixed detection electrode portions 464 and 466 changes. The amount of change in capacitance at this time increases as the amplitude of vibration in the Y direction of the inner mass portion 420 increases. Therefore, the amount of change in capacitance between the inner mass support 404 and the first fixed detection electrode support 468 and the amount of change in capacitance between the inner mass support 404 and the first fixed detection electrode support 470. By detecting this, the angular velocity around the X-axis acting on the MEMS device 402 can be detected. In the MEMS device 402, the capacitance between the inner mass support portion 404 and the first fixed detection electrode support portion 468, and the capacitance between the inner mass support portion 404 and the first fixed detection electrode support portion 470. By detecting the difference, the angular velocity around the X axis acting on the MEMS device 402 can be detected with high accuracy.

  When an angular velocity around the Y axis acts on the MEMS device 402 in a state where the inner mass portion 420 and the outer mass portion 446 are oscillating in the Z direction in opposite phases, the X direction is applied to each of the inner mass portion 420 and the outer mass portion 446. Coriolis force acts. At this time, the inner mass portion 420 is supported by the inner folded beam portions 412, 414, 416, and 418 having high rigidity in the X direction, and thus does not vibrate in the Y direction. On the other hand, since the outer mass portion 446 is supported by the outer folded beam portions 438, 440, 442, and 444 having low rigidity in the X direction, the outer mass portion 446 vibrates in the X direction. At this time, the amplitude of the vibration in the X direction of the outer mass portion 446 becomes larger as the angular velocity around the Y axis acting on the MEMS device 402 becomes larger. As the outer mass portion 446 vibrates in the X direction, the capacitance between the second movable detection electrode portions 456 and 458 and the corresponding second fixed detection electrode portions 480 and 482 changes. The amount of change in capacitance at this time increases as the amplitude of vibration in the X direction of the outer mass portion 446 increases. Therefore, the amount of change in capacitance between the outer mass support 430 and the second fixed detection electrode support 484 and the amount of change in capacitance between the outer mass support 430 and the second fixed detection electrode support 486. By detecting the angular velocity, the angular velocity around the Y axis acting on the MEMS device 402 can be detected. Note that in the MEMS device 402, the capacitance between the outer mass support 430 and the second fixed detection electrode support 484 and the capacitance between the outer mass support 430 and the second fixed detection electrode support 486 are reduced. By detecting the difference, the angular velocity around the Y axis acting on the MEMS device 402 can be accurately detected.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2: MEMS device; 4: First substrate; 6: Second substrate; 8: Multilayer substrate; 10: Silicon layer; 12: Silicon oxide layer; 14: Conductive silicon layer; 16: Frame portion; 20: straight beam part; 22: mass part; 24: first movable electrode part; 24a: support piece; 24b: electrode piece; 26: second movable electrode part; 26a: support piece; 26b: electrode piece; 28a: support piece; 28c: electrode piece; 30: first fixed electrode support part; 32: second fixed electrode part; 32a: support plate; 32b: support piece; 32c: electrode 34: 2nd fixed electrode support part; 36: Recessed part; 38: Pressing member; 40: Bump; 42: Bump; 44: Bump; 46: Through electrode; 48: Through electrode; 50: Through-electrode; 52: Start-up circuit; 54: AC voltage source; 102: MEMS device; 104: First substrate; 106: Second substrate; 108: Third substrate; 110: Multilayer substrate; 112: Silicon oxide layer; 114: conductive silicon layer; 116: silicon oxide layer; 118: silicon layer; 120: frame portion; 122: mass support portion; 124: mass support portion; 126: mass support portion; 128: mass support portion; 132: Folded beam part; 134: Folded beam part; 136: Folded beam part; 138: Mass part; 140: First movable electrode part; 142: First movable electrode part; 144: First movable electrode part; 148: second movable electrode part; 148: second movable electrode part; 152: second movable electrode part; 154: second movable electrode part; 15 158: third movable electrode portion; 158: third movable electrode portion; 160: first fixed electrode portion; 162: first fixed electrode portion; 164: first fixed electrode portion; 166: first fixed electrode portion; 170: first fixed electrode support portion; 172: first fixed electrode support portion; 174: first fixed electrode support portion; 176: second fixed electrode portion; 178: second fixed electrode portion; : 182: second fixed electrode part; 184: second fixed electrode support part; 186: second fixed electrode support part; 188: second fixed electrode support part; 190: second fixed electrode support part 192: third fixed electrode portion; 194: third fixed electrode portion; 196: third fixed electrode support portion; 198: third fixed electrode support portion; 200: recessed portion; 202: recessed portion; 204: pressing member; Press member; 20 216: Through electrode; 216: Through electrode; 218: Through electrode; 218: Through electrode; 220: Bump; 222: Bump; 224: Bump; 226: Bump; 228: Through electrode; 230: Through electrode; 232: Through electrode; 234: Through electrode; 236: Bump; 238: Bump; 240: Bump; 242: Bump; 302: Silicon oxide layer; 304: Polysilicon layer; 402: MEMS device; 406: inner mass support portion; 408: inner mass support portion; 410: inner mass support portion; 412: inner folded beam portion; 414: inner folded beam portion; 416: inner folded beam portion; 418: inner side Folded beam portion; 420: inner mass portion; 422: inner excitation electrode portion; 424: inner excitation 426: first movable detection electrode unit; 428: first mass detection electrode unit; 430: outer mass support unit; 432: outer mass support unit; 434: outer mass support unit; 436: outer mass support unit; 440: Outer folded beam portion; 442: Outer folded beam portion; 444: Outer folded beam portion; 446: Outer mass portion; 448: Outer excitation electrode portion; 450: Outer excitation electrode portion; 452: Movable Start electrode part; 454: Moveable start electrode part; 456: Second move detection electrode part; 458: Second move detection electrode part; 460: Third move detection electrode part; 462: Third move detection electrode part; 1 fixed detection electrode part; 466: first fixed detection electrode part; 468: first fixed detection electrode support part; 470: first fixed detection electrode support part; 472: fixed activation electrode part; 47 476: fixed starting electrode support part; 478: fixed starting electrode support part; 480: second fixed detection electrode part; 482: second fixed detection electrode part; 484: second fixed detection electrode support part; 486: second fixed detection electrode support; 488: third fixed detection electrode; 490: third fixed detection electrode; 492: third fixed detection electrode support; 494: third fixed detection electrode support; 496: Frame part; 498: pressing member; 500: pressing member

Claims (4)

A substrate,
A first movable part elastically supported with respect to the substrate;
A first counter electrode pair having the same potential and arranged opposite each other, and movable in a predetermined sliding direction with respect to the first counter electrode pair, and disposed between the first counter electrode pair A first electrode structure comprising a first slide electrode;
A second counter electrode pair having the same potential and disposed opposite each other, and a second counter electrode pair movable between the second counter electrode pair in the sliding direction and disposed between the second counter electrode pair. A second electrode structure having two slide electrodes,
One of the first counter electrode pair and the first slide electrode is immovable in the slide direction with respect to the first movable part,
One of the second counter electrode pair and the second slide electrode is immovable in the slide direction with respect to the first movable part,
With respect to the sliding direction, the first slide electrode is disposed offset with respect to the first counter electrode pair, and the second slide electrode is disposed without being offset with respect to the second counter electrode pair. A MEMS device.   The MEMS device according to claim 1, further comprising a pressing member that presses a part of the first electrode structure to offset the first slide electrode with respect to the first counter electrode pair in the sliding direction. The substrate is a laminated substrate;
The MEMS device according to claim 2, wherein the first electrode structure and the second electrode structure are formed in the same layer. A second movable part elastically supported with respect to the substrate;
4. The MEMS device according to claim 1, wherein the other of the second counter electrode pair and the second slide electrode is immovable in the slide direction with respect to the second movable portion. 5.

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