JP2010238836A - Mems structure, mems device, and mems device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a MEMS structure that further improves detection accuracy of changes in electrostatic capacity by suppressing displacement between a vibrator and a detection electrode, a MEMS device, and a manufacturing method for the MEMS device. <P>SOLUTION: The MEMS structure 100A includes a vibrator part 1A comprising a support structure part 11 and a vibrator 12b displaceably supported with respect to the support structure part 11, and a detection electrode part 2A comprising a substrate 21 and a detection electrode formed on the substrate 21. The vibrator part 1A and the detection electrode part 2A are joined to each other such that the vibrator 12b and the detection electrode face each other at an interval therebetween in order to detect changes in electrostatic capacity between the vibrator 12b and the detection electrode. The detection electrode is composed of a plurality of mutually separated small electrodes 22a1-22an. Consequently, it allows selection of one or more small electrodes 22a1-22an in accordance with displacement between the vibrator 12b and the detection electrode in a state that the vibrator part 1A and the detection electrode part 2A are joined to each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention includes a vibrating body and a detection electrode facing the vibrating body, detects a change in capacitance between the vibrating body and the detection electrode, and further uses a MEMS structure. The present invention relates to a device and a manufacturing method thereof.

The MEMS (Micro Electro Mechanical System) technology is one of micromachine technologies, and has attracted attention as a manufacturing technology for components used in small electronic devices such as mobile phones.
As one of the MEMS structures formed by the MEMS technology, a cantilever or doubly-supported vibrating body and a detection electrode facing the vibrating body are provided, and a static electricity between the vibrating body and the detection electrode is provided. A MEMS structure for detecting a change in electric capacity is used as a sensor element for a mechanical quantity sensor such as an angular velocity sensor or an acceleration sensor, and its configuration is disclosed in Patent Document 1, for example.
[Conventional configuration example]
FIG. 12 shows a configuration example of a conventional MEMS structure and a manufacturing method thereof. 12A is a side cross-sectional view showing a state before the vibrating body portion 1 and the detection electrode portion 2 are joined. FIGS. 12B and 12C show the vibrating body portion 1 and the detection electrode portion 2. It is a side sectional view (AA sectional view of Drawing 12 (c)) and a top view showing the state after joining detection electrode part 2.

(A) Configuration of vibrating body portion in conventional configuration example:
As shown in FIG. 12A, the vibrating body portion 1 includes a support structure portion 11 (for example, 3200 μm □) and a movable portion 12 (for example, a beam length of 800 μm, a beam width of 200 μm, and a weight size of 800 μm □). It has a configuration. The vibrating body portion 1 is a vibrating body that is a weight portion wider than the beam 12a at the tip of the beam 12a that protrudes in the horizontal direction (rightward in the drawing of FIG. 12A) from the support structure portion 11. 12b is formed, and a gap 13 (for example, a depth of 350 μm) is formed between the movable portion 12 including the beam 12a and the vibration body 12b and the support structure portion 11, and the vibration body 12b is formed in the support structure portion 11. On the other hand, it has a cantilever-like structure supported so as to be displaceable. The vibrating body 12b functions as a movable electrode, and is formed of a material such as Si (silicon) together with the beam 12a and the support structure portion 11.

(B) Configuration of detection electrode unit in conventional configuration example:
As shown in FIG. 12A, the detection electrode unit 2 is connected to a substrate 21 (for example, 2600 μm □) made of an electrically insulating material, for example, and a detection electrode 22a (for example, a size of 600 μm × 550 μm) and a subsequent electronic circuit. The detection electrode connection pad 22c for detection, the detection electrode wiring 22b (for example, 100 μm in width) for conductively connecting the detection electrode 22a and the detection electrode connection pad 22c, and the movable electrode pad 23a are formed. ing.
(C) Joining of the vibrating body and the detection electrode in the conventional configuration example:
The vibrating body portion 1 and the detection electrode portion 2 are joined by, for example, anodic bonding to configure the MEMS structure 100 shown in FIGS. After the above-described bonding, the movable electrode pad 23a and the support structure portion 11 are electrically connected to each other by, for example, a metallization process. In addition, anodic bonding is a technique in which silicon and glass are superposed, heated and applied with a DC voltage of several hundred volts to form a covalent bond of Si-O. Silicon and glass are bonded to each other. Since it is directly joined without intervening, it has the feature of strong joint strength.
[Application of MEMS structure to sensor element]
The MEMS structure 100 manufactured as shown in FIG. 12 has a structure in which the vibrating body 12b (movable electrode) and the detection electrode 22a face each other with a space therebetween, and the vibrating body 12b (movable electrode) and the detection body. It functions as a sensor element that detects a change in the capacitance C1 between the electrode 22a and measures mechanical quantities such as acceleration and angular velocity through displacement of the vibrating body detected based on the change in capacitance. can do.

JP 2006-46995 A

In the MEMS structure that detects a change in the capacitance C1 between the vibrating body (movable electrode) and the detection electrode, the positional deviation between the vibrating body and the detection electrode is caused in a state in which the vibrating body and the detection electrode are joined. If this occurs, for example, as shown in (a) to (b) below, the displacement of the vibrating body cannot be accurately detected based on the capacitance change due to a decrease in the electrode facing area, etc., and this MEMS structure The measurement accuracy of a mechanical quantity sensor such as an acceleration sensor or an angular velocity sensor using a body is low.
(A) A MEMS structure that detects a change in capacitance C1 due to a change in inter-electrode distance associated with a displacement in the direction perpendicular to the detection electrode surface of the vibrating body (movable electrode) (the depth direction in FIG. 12C). Then, when the positional deviation between the vibrating body and the detection electrode occurs along the direction parallel to the detection electrode plane (vertical direction or horizontal direction in the paper surface of FIG. 12C), the electrode is compared with the case where there is no positional deviation. Since the capacitance C1 is reduced by the smaller facing area, the capacitance C1 can be accurately detected, for example, by being more greatly affected by stray capacitance around the capacitance detection circuit. This makes it impossible to accurately detect the displacement of the vibrating body.

  (B) A MEMS structure that detects a change in capacitance C1 due to a change in electrode facing area due to a displacement in the direction parallel to the detection electrode surface of the vibrating body (movable electrode) (up and down direction in the plane of FIG. 12C). Then, when the positional deviation between the vibrating body and the detection electrode occurs along the direction parallel to the detection electrode surface and perpendicular to the direction of the displacement (the left-right direction in the paper surface of FIG. 12C), Since the capacitance C1 is smaller by the smaller electrode facing area than when there is no positional deviation, the static capacitance around the capacitance detection circuit is more greatly affected by static capacitance. The capacitance C1 cannot be accurately detected, and thus the displacement of the vibrating body cannot be accurately detected. Further, when the displacement of the vibrating body and the detection electrode has occurred along the direction of the displacement (the vertical direction on the paper surface of FIG. 12C), the capacitance C1 in the state where the vibrating body is at the reference position. Since the magnitude of is deviated from the capacitance value when there is no positional deviation, the displacement of the vibrating body cannot be accurately detected.

As a cause of the positional deviation between the vibrating body (movable electrode) and the detection electrode in a state where the vibrating body portion and the detection electrode portion are joined, the detection electrode is formed on the substrate in the manufacturing process of the detection electrode portion. Position error, and position error when aligning (alignment) both in the joining process of the vibrating body part and the detection electrode part can be considered.
FIG. 13 is an explanatory diagram showing a positional shift in the MEMS structure of FIG. 12, in the case where a positional error occurs when aligning both in the joining process of the vibrating body part and the detection electrode part. The MEMS structure after joining is shown. FIGS. 13A and 13B are a side cross-sectional view (cross-sectional view taken along line AA in FIG. 13B) and a plan view showing a state after the vibrating body portion 1 and the detection electrode portion 2 are joined. And correspond to (b) and (c) of FIG. 12, respectively. In FIG. 13B, the relative position of the substrate 21 with respect to the support structure portion 11, that is, the relative position of the detection electrode portion 2 with respect to the vibrating body portion 1 is leftward and downward in the drawing with respect to a reference position indicated by a two-dot chain line. The directions are shifted by L1a and L1b, respectively. When there is no position error when forming the detection electrode 22a on the substrate 21 in the manufacturing process of the detection electrode unit 2, the relative position of the detection electrode 22a with respect to the vibrating body 12b (movable electrode) is also the same deviation amount L1a. And L1b.

In FIG. 13, the detection electrode 22a is displaced relative to the vibrating body 12b (movable electrode) by the relative displacement (L1a, L1b), as described in the above items (a) to (b), based on the capacitance change. The displacement of the vibrating body 12b cannot be detected accurately.
For this reason, the present invention solves the above-mentioned problems, and can suppress the displacement between the vibration part and the detection electrode, thereby increasing the detection accuracy of the displacement of the vibrating body based on the change in capacitance. It is an object to provide a body, a MEMS device, and a manufacturing method thereof.

In order to achieve the above object, according to the present invention, a MEMS structure is composed of a support structure section and a vibration body supported to be displaceable with respect to the support structure section, a substrate, and the substrate. A detection electrode unit comprising a detection electrode formed thereon, and the vibrating body unit and the detection electrode unit are joined so that the vibrating body and the detection electrode face each other with a gap therebetween, and the vibrating body In the MEMS structure configured to detect a change in capacitance between the detection body and the detection electrode, the detection electrode includes a plurality of small electrodes separated from each other, thereby detecting the vibration body portion and the detection body. One or more small electrodes can be selected in accordance with the positional deviation between the vibrating body and the detection electrode in a state where the electrode portion is joined (Invention of Claim 1) ).
According to the first aspect of the present invention, the position error when forming the detection electrode on the substrate in the detection electrode portion manufacturing step and the alignment (alignment) in the bonding step of the vibrating body portion and the detection electrode portion. ) As a countermeasure against both of the position error when the vibration body part and the detection electrode part are joined, one or more small electrodes are used, for example, in correspondence with the positional deviation between the vibration body and the detection electrode. A position that is suitable for detecting changes in capacitance according to the displacement of the electrode position that occurs when the detection electrode part is manufactured or when the vibrating body part and the detection electrode part are joined, by selecting the switch circuit connected to the subsequent stage. Thus, the detection accuracy of the displacement of the vibrating body based on the capacitance change can be further increased.

In the MEMS structure according to claim 1, each of the small electrodes in the detection electrode unit is formed when the vibration body unit and the detection electrode unit are joined, because the substrate is formed of a transparent plate member. It is good to be the structure which can be confirmed optically from the outside of the anti-vibration body part side (invention of Claim 2).
According to the second aspect of the present invention, the position error when forming the detection electrode on the substrate in the detection electrode portion manufacturing process and the alignment (alignment) in the bonding step of the vibrating body portion and the detection electrode portion. ) As a further countermeasure against both of the position error when the vibrating body part and the detection electrode part are joined, the position of each small electrode in the detection electrode part is passed through the transparent substrate from the outside on the anti-vibration body part side. Thus, for example, the alignment can be performed while confirming by optical means such as an optical microscope, so that the positional deviation between the vibration body and the detection electrode that occurs when the vibration body section and the detection electrode section are joined can be suppressed. As a result, the positional deviation between the vibration body and the detection electrode that occurs when the vibration body section and the detection electrode section are joined becomes excessively large, and the positions of all the small electrodes that constitute the detection electrode are used to detect a change in capacitance. It is possible to prevent a problem that the position does not fit. Accordingly, it is possible to reliably increase the detection accuracy of the displacement of the vibrator based on the change in capacitance by selecting one or more small electrodes at positions suitable for detection of the change in capacitance.

Further, the MEMS structure according to the first aspect may have a configuration in which a fitting portion is provided to suppress a positional deviation between the vibrating body and the detection electrode that occurs when the vibrating body portion and the detection electrode portion are joined. (Invention of claim 3).
According to the third aspect of the present invention, as a further countermeasure against the position error when aligning both in the joining process of the vibrating body portion and the detection electrode portion, the vibration body portion and the detection electrode portion By aligning the fitting part so that the fitting part is fitted at the time of joining, the positional deviation between the vibrating body and the detection electrode that occurs when joining the vibrating body part and the detection electrode part can be suppressed to be small. As a result, the positional deviation between the vibration body and the detection electrode that occurs when the vibration body section and the detection electrode section are joined becomes excessively large, and the positions of all the small electrodes that constitute the detection electrode are used to detect a change in capacitance. It is possible to prevent a problem that the position does not fit. Accordingly, it is possible to reliably increase the detection accuracy of the displacement of the vibrator based on the change in capacitance by selecting one or more small electrodes at positions suitable for detection of the change in capacitance.

In the MEMS structure according to claim 3, as the fitting portion, a vibration having an inner peripheral shape that fits the outer peripheral shape of the detection electrode portion on a surface facing the detection electrode portion in the vibration body portion. It is preferable that the body side recess is formed (invention of claim 4).
In the MEMS structure according to claim 3, as the fitting portion, a convex portion (or a concave portion) on the vibrating body portion side is formed on the surface of the vibrating body portion facing the detection electrode portion, and the detection is performed. It is good also as a structure which formed the recessed part (or convex part) by the side of the detection electrode which fits the convex part (or recessed part) by the side of the said vibrating body part on the surface facing the vibrating body part in an electrode part. invention).
According to the present invention, a MEMS device using the MEMS structure according to any one of claims 1 to 5 is provided with a switch circuit to which the small electrodes are connected, so that a vibrating body is provided. A configuration in which one or more small electrodes can be selected by the switch circuit in response to a positional shift between the vibrating body and the detection electrode in a state where the portion and the detection electrode portion are joined. (Invention of claim 6)

According to the sixth aspect of the present invention, one or more small electrodes are selected by the switch circuit in accordance with the positional deviation between the vibrating body and the detection electrode when the vibrating body and the detection electrode are joined. By using the small electrode at the position suitable for detecting the change in capacitance according to the displacement of the electrode position that occurs when the detection electrode part is manufactured or when the vibrating body part and the detection electrode part are joined, As a result, the detection accuracy of the displacement of the vibrating body based on the capacitance change can be further increased.
Further, according to the present invention, there is provided a method of manufacturing a MEMS device formed on a substrate and the substrate, a vibrating body portion including a supporting structure portion and a vibrating body supported to be displaceable with respect to the supporting structure portion. A detection electrode unit composed of a detection electrode, and the vibration body and the detection electrode unit are joined so that the vibration body and the detection electrode face each other with a space therebetween. In a method of manufacturing a MEMS device using a MEMS structure configured to detect a change in capacitance between the plurality of small electrodes, the detection electrode is composed of a plurality of small electrodes separated from each other. A switch circuit is provided, and one or more small electrodes are connected to the switch circuit in accordance with a positional deviation between the vibrating body and the detection electrode in a state where the vibrating body and the detection electrode are joined. Selected by The configuration is selected (the invention of claim 7).

According to the seventh aspect of the present invention, the position error when forming the detection electrode on the substrate in the detection electrode portion manufacturing process and the alignment (alignment) in the bonding step of the vibrating body portion and the detection electrode portion. ) As a countermeasure against both positional errors when switching, one or more small electrodes are switched in response to the positional deviation between the vibrating body and the detection electrode when the vibrating body and the detection electrode are joined. By selecting according to the circuit, the small electrode in the position suitable for detecting the change in capacitance is detected in accordance with the electrode position deviation that occurs when the detection electrode part is manufactured or when the vibrating body part and the detection electrode part are joined. As a result, the detection accuracy of the displacement of the vibrator based on the change in capacitance can be further increased.
In the method for manufacturing a MEMS device according to claim 7, the substrate is configured by a transparent plate-like member, and each small electrode in the detection electrode unit is bonded at the time of joining the vibrating body unit and the detection electrode unit. A configuration may be adopted in which the position is optically confirmed from the outside on the anti-vibration body side (the invention of claim 8).

  According to the eighth aspect of the present invention, the position error when forming the detection electrode on the substrate in the detection electrode portion manufacturing step, and the alignment (alignment) in the bonding step of the vibrating body portion and the detection electrode portion. ) As a further countermeasure against both of the position error when the vibrating body part and the detection electrode part are joined, the position of each small electrode in the detection electrode part is passed through the transparent substrate from the outside on the anti-vibration body part side. Thus, for example, by performing alignment while confirming with an optical means such as an optical microscope, it is possible to suppress a positional deviation between the vibrating body and the detection electrode that occurs when the vibrating body section and the detection electrode section are joined. As a result, the positional deviation between the vibration body and the detection electrode that occurs when the vibration body section and the detection electrode section are joined becomes excessively large, and the positions of all the small electrodes that constitute the detection electrode are used to detect a change in capacitance. It is possible to prevent a problem that the position does not fit. Accordingly, it is possible to reliably increase the detection accuracy of the displacement of the vibrator based on the change in capacitance by selecting one or more small electrodes at positions suitable for detection of the change in capacitance.

Further, in the method for manufacturing a MEMS device according to claim 7, a fitting portion is provided to suppress a positional deviation between the vibrating body and the detection electrode that occurs when the vibrating body portion and the detection electrode portion are joined. It is good also as a structure which aligns so that the said fitting part may fit at the time of joining of a body part and a detection electrode part (invention of Claim 9).
According to the ninth aspect of the present invention, as a further countermeasure against a position error when aligning both in the joining process of the vibrating body portion and the detection electrode portion, the vibration body portion and the detection electrode portion By aligning the fitting part so that the fitting part is fitted at the time of joining, the positional deviation between the vibrating body and the detection electrode that occurs when joining the vibrating body part and the detection electrode part can be suppressed to be small. As a result, the positional deviation between the vibration body and the detection electrode that occurs when the vibration body section and the detection electrode section are joined becomes excessively large, and the positions of all the small electrodes that constitute the detection electrode are used to detect a change in capacitance. It is possible to prevent a problem that the position does not fit. Accordingly, it is possible to reliably increase the detection accuracy of the displacement of the vibrator based on the change in capacitance by selecting one or more small electrodes at positions suitable for detection of the change in capacitance.

In the MEMS device manufacturing method according to claim 9, the fitting portion has an inner peripheral shape that fits to the outer peripheral shape of the detection electrode portion on the surface of the vibrating body portion facing the detection electrode portion. It is preferable to form a concave portion on the vibrating body portion side and align the detecting electrode portion and the concave portion on the vibrating body portion side when the vibrating body portion and the detection electrode portion are joined. (Invention of Claim 10).
Moreover, in the manufacturing method of the MEMS device according to claim 9, as the fitting portion, a convex portion (or a concave portion) on the vibrating body portion side is formed on a surface facing the detection electrode portion in the vibrating body portion, and A detection electrode portion-side recess (or projection) that fits with the vibration body portion-side projection (or recess) is formed on a surface of the detection electrode portion that faces the vibration body portion. It is good also as a structure which aligns so that the convex part (or recessed part) by the side of a vibrating body part and the recessed part (or convex part) by the side of a detection electrode part may fit at the time of joining with an electrode part. Invention).

  According to the present invention, as described above, in accordance with the displacement of the electrode position that occurs when the detection electrode portion is manufactured or when the vibrating body portion and the detection electrode portion are joined, the small size is in a position suitable for detecting a change in capacitance. The electrode can be used as a detection electrode, and thereby the detection accuracy of the displacement of the vibrating body based on the change in capacitance can be further increased.

Schematic process drawing of the manufacturing method of the MEMS structure according to the first embodiment of the present invention. FIG. 1 is a structural diagram of a vibrating body in the MEMS structure of FIG. FIG. 1 is a structural diagram of a detection electrode portion in the MEMS structure of FIG. Explanatory drawing which shows the position shift in the MEMS structure of FIG. The circuit diagram which shows the circuit structural example of the MEMS device using the MEMS structure of FIG. Schematic process drawing of a method for manufacturing a MEMS structure according to Embodiment 2 of the present invention. Schematic process drawing of a method for manufacturing a MEMS structure according to Embodiment 3 of the present invention. FIG. 7 is a structural diagram of a vibrating body in the MEMS structure. Schematic process drawing of a method for manufacturing a MEMS structure according to Example 4 of the present invention. FIG. 9 is a structural diagram of a vibrating body in the MEMS structure. FIG. 9 is a structural diagram of the detection electrode portion in the MEMS structure. Schematic process diagram of conventional MEMS structure manufacturing method Explanatory drawing which shows the position shift in the MEMS structure of FIG.

Hereinafter, embodiments of the present invention will be described based on examples shown in FIGS. About the same component, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted. In addition, this invention is not limited to the following embodiment, In the range which does not change the summary, it can implement suitably.
Embodiment of the present invention

In the first embodiment of the present invention, the position error when forming the detection electrode on the substrate in the manufacturing process of the detection electrode unit and the alignment (alignment) of both in the bonding process of the vibrating body unit and the detection electrode unit As a countermeasure against both of the positional errors at the time, the detection electrode is composed of a plurality of small electrodes separated from each other, and the vibration body and the detection electrode are in a state where the vibration body portion and the detection electrode portion are joined. One or more small electrodes are selected by, for example, a switch circuit connected in the subsequent stage in accordance with the positional deviation. Thereby, in Example 1, the small electrode in the position suitable for the detection of the capacitance change is detected in accordance with the electrode position shift that occurs when the detection electrode part is manufactured or when the vibrating body part and the detection electrode part are joined. It can be used as an electrode.
1 to 5 show the structure of a MEMS structure, a MEMS device, and a manufacturing method thereof according to Embodiment 1 of the present invention. FIG. 1 is a schematic process diagram of a method for manufacturing a MEMS structure 100A according to Embodiment 1 of the present invention. In FIGS. 1B to 1C, a vibrating body portion 1A and a detection electrode portion 2A are joined. A structure of the MEMS structure 100A is shown. 2 is a structural diagram of the vibrating body portion 1A, and FIG. 3 is a structural diagram of the detection electrode portion 2A. FIG. 4 is an explanatory diagram showing a positional shift in the MEMS structure 100A of FIG. 5 is a circuit diagram showing a circuit configuration example of a MEMS device using the MEMS structure 100A of FIG. 1 to 5, elements having the same functions as those of the conventional configuration example shown in FIG. 12 are denoted by the same reference numerals, and only portions different from the conventional configuration example (FIG. 12) will be described.

(A) Configuration of the vibrating body portion in the first embodiment:
2A and 2B are a side sectional view (AA sectional view of FIG. 2B) and a plan view of the vibrating body portion 1A, respectively. As shown in FIG. 2, the vibrating body portion 1 </ b> A is similar to the vibrating body portion 1 described in FIG. 12, with the support structure portion 11 (for example, 3200 μm □) and the movable portion 12 (for example, a beam length of 800 μm, a beam width of 200 μm, And a weight size of 800 μm □).
The vibrating body portion 1A is a vibrating body that is a weight portion that is wider than the beam 12a at the tip of the beam 12a that protrudes in the horizontal direction from the support structure portion 11 (the right direction in FIG. 2A). 12b is formed, and a gap 13 (for example, a depth of 350 μm) is formed between the movable portion 12 including the beam 12a and the vibration body 12b and the support structure portion 11, and the vibration body 12b is formed in the support structure portion 11. On the other hand, it has a cantilever-like structure supported so as to be displaceable. The vibrating body 12b functions as a movable electrode, and is formed of a material such as Si (silicon) together with the beam 12a and the support structure portion 11.

In addition, in the state where the vibrating body portion 1A and the detection electrode portion 2A are joined, the support structure portion 11 made of Si (silicon) or the like of the vibrating body portion 1A, the detection electrode 22a and the detection electrode wiring 22b of the detection electrode portion 2A, In order to prevent contact with each other, a concave portion 14 having a depth d1 from the upper surface is formed on the upper surface side (the upper side in FIG. 2A) of the vibrating body portion 1A.
For example, an SOI (Silicon on Insulator) wafer in which an upper Si layer and a lower Si layer are sandwiched between insulating layers made of SiO ₂ can be used to manufacture the vibrating body portion 1A. As an example of the SOI wafer, the lower Si layer has a thickness of 200 to 525 μm, the insulating layer has a thickness of 0.2 to 1.0 μm, and the upper Si layer has a thickness of 2 to 30 μm. Using this SOI wafer, a gap 13 between the vibrating body 12 and the support structure 11, a recess 14, and the like are formed by photolithography or the like, and the vibrating body 1 </ b> A is manufactured.

(B) Configuration of the detection electrode unit in Example 1:
3A and 3B are a side sectional view (AA sectional view of FIG. 3B) and a plan view of the detection electrode portion 2A, respectively. As shown in FIG. 3, the detection electrode unit 2A includes, for example, a detection electrode, a detection electrode connection pad for connection to a subsequent electronic circuit, and a detection electrode on a substrate 21 (eg, 2600 μm □) made of an electrically insulating material. This is a configuration in which a detection electrode wiring and a movable electrode pad are formed to be conductively connected to the detection electrode connection pad, and the basic configuration is the same as that of the conventional detection electrode unit 2 shown in FIG. There are differences in the following points.
That is, in the detection electrode unit 2A according to the first embodiment, as shown in FIG. 3B, the detection electrode is a plurality of small electrodes 22a1 to 22an (for example, size 250 μm × 225 μm) (n is an integer of 2 or more, In FIG. 3B, n = 5) and a plurality of small electrode wirings 22b1 to 22bn (for example, a width of 100 μm) respectively connected to the small electrodes 22a1 to 22an are formed as detection electrode wirings. deep. Further, as the detection electrode connection pads, small electrode connection pads 22c1 to 22cn are provided at the end portions of the small electrode wirings 22b1 to 22bn, respectively, so that they can be connected to a subsequent switch circuit (not shown).

The through holes 22d1 to 22dn are formed in the small electrode connection pads 22c1 to 22cn on the substrate 21, and the metal layers 22e1 to 22en are formed on the inner peripheral surfaces of the through holes 22d1 to 22dn. The small electrode connection pads 22c1 to 22cn and the small electrode wirings 22b1 to 22bn are electrically connected through 22e1 to 22en. Further, a through hole 23b is formed in the portion of the movable electrode pad 23a in the substrate 21, and a metal layer 23c electrically connected to the movable electrode pad 23a is formed on the inner peripheral surface of the through hole 23b.
The small electrodes 22a1 to 22an, the small electrode wirings 22b1 to 22bn, the small electrode connection pads 22c1 to 22cn and the movable electrode pad 23a in the detection electrode unit 2A are made of, for example, copper or the like on the substrate 21 made of a glass plate. A metal film is formed into a thin film by a method such as vapor deposition or sputtering, and a resist is formed on the surface of the metal film so as to have the shape of a desired small electrode, small electrode wiring, small electrode connection pad, and movable electrode pad. After patterning, unnecessary portions of the metal film are removed by dry etching or wet etching, and small electrodes 22a1 to 22an, small electrode wirings 22b1 to 22bn, small electrode connection pads 22c1 to 22cn, and movable electrodes It can be formed by leaving only the metal film portion of the pad 23a.

Further, the through holes 22d1 to 22dn and the through holes 23b can be processed by a method such as sandblasting with respect to the substrate 21 made of, for example, a glass plate, and the inner peripheral surfaces of the through holes 22d1 to 22dn and the through holes 23b can be processed. The metal layers 22e1 to 22en and 23c can be formed by a method such as electroless plating.
Further, as the substrate 21 in the detection electrode portion 2A, a Si substrate may be used instead of the glass plate. When a Si substrate is used as the substrate 21, an insulating layer such as SiO ₂ is formed on the substrate 21, and the small electrodes 22a1 to 22an, the small electrode wirings 22b1 to 22bn, and the small electrode are formed on the insulating layer. By forming the connection pads 22c1 to 22cn, the detection electrode unit 2A can be manufactured.
Note that the number n of small electrodes in the present invention is not limited to the five shown in FIG.

(C) Joining of the vibrating body and the detection electrode in Example 1
FIG. 1A is a side cross-sectional view showing a state before the vibrating body portion 1A and the detection electrode portion 2A are joined. FIGS. 1B and 1C show the vibrating body portion 1A and FIG. It is a side sectional view (AA sectional view of Drawing 1 (c)) and a top view showing the state after joining detection electrode part 2A. As shown in FIG. 1, the vibrating body 1 </ b> A and the detection electrode 2 </ b> A are joined by, for example, anodic bonding to configure the MEMS structure shown in FIGS. 1 (b) to 1 (c).
After the joining, the inner peripheral surface of the through hole 23b in the detection electrode portion 2A and the upper surface portion region 23d of the support structure portion 11 are metalized so that the movable electrode pad 23a and the support structure portion 11 are electrically connected. It is set as the structure connected to. In FIG. 1A, as described above, the metal layer 23c connected to the movable electrode pad 23a is already formed on the inner peripheral surface of the through hole 23b in the detection electrode portion 2A before bonding. Although the configuration is shown, the metal layer 23c on the inner peripheral surface of the through hole 23b may be formed for the first time by metallization after bonding.

(D) Small electrode selection method:
One of the plurality of small electrodes 22a1 to 22an is matched to the amount of positional deviation between the vibrating body 12b and the detection electrodes (the plurality of small electrodes 22a1 to 22an) generated when the vibration body portion 1A and the detection electrode portion 2A are joined. One or more small electrodes are selected and used as detection electrodes. A switch circuit is used to select the small electrode. That is, each of the small electrodes 22a1 to 22an is connected to a switch circuit in the subsequent electronic circuit unit, and one or more small electrodes to be used are selected by turning on / off the switch circuit.
By preparing a plurality of small electrodes 22a1 to 22an, positions of the vibrating body 12b and the detection electrodes (a plurality of small electrodes 22a1 to 22an) in a state where the vibrating body portion 1A and the detection electrode portion 2A are joined. Depending on the mode of deviation, one or more small electrodes in a position suitable for detection of capacitance change can be selected as detection electrodes, thereby increasing the detection accuracy of the displacement of the vibrator based on the capacitance change. Can be higher.

Applying the first embodiment is effective in the following two points as a countermeasure against electrode position deviation.
(A) In the manufacturing process of the detection electrode portion 2A, position correction corresponding to the position shift of the detection electrode formed on the substrate 21 can be performed.
(B) It is possible to perform position correction corresponding to a positional deviation that occurs when alignment (alignment) is performed in the joining process of the vibrating body portion 1A and the detection electrode portion 2A.
As a selection method of the small electrodes, for example, one small electrode closest to the center position of the vibrating body 12b is selected as one or more small electrodes at a position suitable for detection of capacitance change. Alternatively, two or more small electrodes close to the center position of the vibrating body 12b may be selected.
Further, as a method of determining which small electrode is close to the center position of the vibrating body 12b before selecting the small electrode to be used as the detection electrode, for example, each switching operation by a switch circuit in the electronic circuit unit at the subsequent stage is used. Each of the capacitances Ca1 to Can between the small electrodes 22a1 to 22an and the vibrating body 12b is individually measured, and the small electrode whose larger capacitance value is measured is closer to the center position of the vibrating body 12b. A method for determining an electrode can also be applied. The capacitance measurement can be performed by a capacitance measurement circuit connected to a switch circuit in the electronic circuit section at the subsequent stage, for example, as shown in FIG.

(E) Example of correspondence to misalignment in MEMS structure:
FIG. 4 is an explanatory diagram showing an example of misalignment in the MEMS structure 100A of FIG. 1, and a positional error occurs when aligning them in the bonding process of the vibrating body and the detection electrode. The MEMS structure after joining in the case of a case is shown.
4A and 4B are a side cross-sectional view (cross-sectional view taken along line AA in FIG. 4B) and a plan view showing a state after the vibrating body portion 1 and the detection electrode portion 2 are joined. And correspond to (b) and (c) of FIG. 1, respectively. In FIG. 4B, the relative position of the substrate 21 with respect to the support structure portion 11, that is, the relative position of the detection electrode portion 2A with respect to the vibrating body portion 1A is leftward and downward with respect to the reference position indicated by a two-dot chain line. The directions are shifted by L1a and L1b, respectively. When there is no position error when forming the detection electrodes (the plurality of small electrodes 22a1 to 22an) on the substrate 21 in the manufacturing process of the detection electrode portion 2A, the detection electrodes (the plurality of small electrodes) with respect to the vibrating body 12b (movable electrode). The relative positions of the electrodes 22a1 to 22an) are also shifted by the same shift amounts L1a and L1b as described above.

And in Example 1, it matched with the detection of a capacitance change corresponding to the position shift of a vibrating body and a detection electrode in the state where such vibrating body part 1A and detection electrode part 2A were joined. As the small electrode at the position, one small electrode closest to the center position of the vibrating body 12b (small electrode 22a4 in FIG. 4B) may be selected, and 2 may be selected at the center position of the vibrating body 12b. Two or more small electrodes (in FIG. 4B, for example, two of the closest small electrode 22a4 and the second closest small electrode 22a3) may be selected, thereby changing the capacitance. The small electrode at a position suitable for the detection of can be used as the detection electrode, and the detection accuracy of the displacement of the vibrating body based on the change in capacitance can be further increased.
(F) Configuration example of the switch circuit:
When a MEMS device is configured using the MEMS structure 100A described above, for example, an electronic circuit unit 200 including a switch circuit as shown in FIG. 5 is provided in the subsequent stage.

In FIG. 5, an electronic circuit unit 200 is connected to the MEMS structure 100A, and the electronic circuit unit 200 includes a switch circuit 231 including switches SW1 to SW5 connected to the small electrodes 22a1 to 22a5 of the MEMS structure 100A, respectively. Is provided. The switches SW1 to SW5 are controlled to be connected to either the a side or the b side by control command signals S1 to S5 from the switch control circuit 232, respectively. The a side of the switches SW1 to SW5 is connected to the inverting input terminal of the operational amplifier 233, and the b side of the switches SW1 to SW5 is connected to the non-inverting input terminal of the operational amplifier 233. The switches SW1 to SW5 are illustrated with contact symbols in FIG. 5, but may be configured with semiconductor switch elements.
An AC signal generator 234 is connected to the non-inverting input terminal of the operational amplifier 233, and a feedback resistor 235 (Rf) is connected between the inverting input terminal and the output terminal of the operational amplifier 233. .

When, for example, the small electrode 22a4 is selected as the detection electrode among the small electrodes 22a1 to 22a5, only the switch SW4 among the switches SW1 to SW5 is connected to the a side, and the other switches SW1 to SW3 and SW5 are connected to the b side. It becomes a state. For this reason, only the small electrode 22a4 is connected to the inverting input terminal of the operational amplifier 233 as a detection electrode, and the small electrodes 22a1 to 22a3 and 22a5 are floating from the ground potential (GND) and the non-inverting input terminal of the operational amplifier 233. Will be connected to. The vibrator 12b (movable electrode) is connected to the ground potential (GND).
In such a connection state, the operational amplifier 233 is subjected to negative feedback via the feedback resistor 235 and the open loop gain of the operational amplifier 233 is extremely large. Therefore, the input side of the operational amplifier 233 is in an imaginary short state. The potential difference between the inverting input terminal and the non-inverting input terminal is almost zero.

Since an AC signal is applied from the AC signal generator 234 to the non-inverting input terminal of the operational amplifier 233, the output voltage Vo of the operational amplifier 233 is Vo = Vi (1 + jωRf * Cx). Here, Cx is a capacitance value between the vibrating body 12b and the small electrode 22a4 (selected as the detection electrode), Rf is a resistance value of the feedback resistor 235, and Vi and ω are The voltage and angular frequency of the AC signal from the AC signal generator 234.
Therefore, by measuring the output voltage Vo of the operational amplifier 233, the electrostatic capacitance between the vibrating body 12b and the small electrode 22a4 (selected as the detection electrode) can be detected.
Here, in the configuration of FIG. 5, a conductor line such as the small electrode wiring 22 b 4 from the small electrode 22 a 4 selected as the detection electrode to the input side of the operational amplifier 233, and the small electrodes 22 a 1 to 22 not selected as the detection electrode. A stray capacitance is formed between the conductor lines such as the small electrode wirings 22b1 to 22b3 and 22b5 from the terminals 22a3 and 22a5 to the input side of the operational amplifier 233. May have a non-negligible magnitude with respect to the capacitance between the vibrating body 12b and the small electrode 22a4 (selected as the detection electrode).

However, in the configuration of FIG. 5, as described above, the stray capacitance between the conductor lines is canceled when the input side of the operational amplifier 233 is in an imaginary short state, so the small electrode 22a4 is used as the detection electrode. The influence on the accuracy of capacitance detection can be suppressed.
FIG. 5 shows a circuit configuration example including five small electrodes (22a1 to 22a5) and corresponding five switches (SW1 to SW5). However, the number of small electrodes and the corresponding switch The number is not limited to five.
Further, the configuration of the electronic circuit unit in the MEMS device according to the present invention is not limited to the circuit configuration of FIG. 5, and one or more small electrodes can be selected as the detection electrode from the plurality of small electrodes 22a1 to 22an. Any configuration that can reduce the influence of stray capacitance between the conductor lines as described above may be used.

  In the second embodiment of the present invention, in addition to the configuration of the first embodiment, the position error when forming the detection electrode on the substrate in the manufacturing process of the detection electrode portion, and the bonding step of the vibrating body portion and the detection electrode portion In this case, the substrate is made of a transparent plate-shaped member, and the vibration body portion and the detection electrode portion are arranged together. At the time of joining, the position of each small electrode in the detection electrode unit is aligned while being confirmed from the outside on the anti-vibration body side through an optical means such as an optical microscope through a transparent substrate. As a result, in the second embodiment, the positional deviation between the vibrating body and the detection electrode that occurs when the vibrating body portion and the detection electrode portion are joined can be suppressed to be small. Therefore, the vibration that occurs when the vibrating body portion and the detection electrode portion are joined. It is possible to prevent such a problem that the position deviation between the body and the detection electrode becomes too large, and the positions of all the small electrodes constituting the detection electrode are not suitable for the detection of the capacitance change. It becomes possible to reliably increase the detection accuracy of the displacement of the vibrator based on the change in capacitance by selecting one or more small electrodes at positions suitable for detection of the change in capacitance.

FIG. 6 shows the structure of a MEMS structure and a manufacturing method thereof according to Embodiment 2 of the present invention. FIG. 6 is a schematic process diagram of a method for manufacturing a MEMS structure according to a second embodiment of the present invention. In FIGS. 6B to 6C, the vibrating body portion 1B and the detection electrode portion 2B are joined. The structure of the MEMS structure 100B is shown. 6, elements having the same functions as those of the conventional configuration example illustrated in FIG. 12 or the first embodiment described with reference to FIGS. 1 to 5 are denoted by the same reference numerals, and only different portions will be described.
(A) Configuration of vibrating body part in Example 2:
As the vibrating body portion 1B in the second embodiment, one having the same configuration as that of the vibrating body portion 1A (FIG. 2) in the first embodiment can be used.
(B) Configuration of detection electrode unit in Example 2:
The detection electrode unit 2B according to the second embodiment may have the same structure as that of the detection electrode unit 2A (FIG. 3) according to the first embodiment. In particular, a transparent glass plate is used as the substrate 21. There are features. Thereby, in Example 2, when joining the vibrating body part 1B and the detection electrode part 2B, the position of the small electrodes 22a1 to 22an in the detection electrode part 2B is confirmed by optical means through the transparent substrate 21. be able to.

In addition, the board | substrate 21 in the detection electrode part 2B is not limited to said glass plate, What is necessary is just an optically transparent plate-shaped member.
(C) Joining of the vibrating body part and the detection electrode part in Example 2
FIG. 6A is a side sectional view showing a state before the vibrating body portion 1B and the detection electrode portion 2B are joined, and FIGS. 6B and 6C show the vibrating body portion 1B and FIG. It is a side sectional view (AA sectional view of Drawing 6 (c)) and a top view showing the state after joining detection electrode part 2B. As shown in FIG. 6, the vibrating body portion 1 </ b> B and the detection electrode portion 2 </ b> B are joined by, for example, anodic bonding to configure the MEMS structure 100 </ b> B shown in FIGS.
In Example 2, as described above, since the transparent glass plate is used as the substrate 21 in the detection electrode unit 4B, the detection electrode unit 2B is bonded to the vibrating body unit 1B and the detection electrode unit 2B. While confirming the relative positions of the small electrodes 22a1 to 22an with respect to the vibrating body portion 1B by optical means such as an optical microscope through the transparent substrate 21, alignment is performed based on the following criteria, for example. be able to.

(A) Among the small electrodes 22a1 to 22an, alignment is performed so that the position of one small electrode (for example, 22a3) coincides with the center position of the vibrating body 12b.
(B) Among the small electrodes 22a1 to 22an, alignment is performed so that the position of as many small electrodes as possible falls within the region facing the vibrating body 12b.
6 corresponds to a positional error when the detection electrodes (small electrodes 22a1 to 22an) are formed on the substrate 11 in the manufacturing process of the detection electrode portion 2B, so that optical means are used through the transparent substrate 21. While being confirmed, the joining state is shown when the small electrode 22a3, which is the small electrode at the center of the small electrodes 22a1 to 22an, is aligned so as to be closest to the center position of the vibrating body 12b. When alignment is performed to cope with such an error in the detection electrode formation position on the substrate, the relative position of the substrate 21 with respect to the support structure portion 11 is relative to the reference position (two-dot chain line in FIG. 6C). (For example, in FIG. 6 (c), L2a and L2b are respectively leftward and downward in the drawing), but the positional relationship between the vibrating body 12b and the detection electrode becomes more appropriate.

In Example 2, since a transparent glass plate is used as the substrate 21 in the detection electrode portion 2B, the vibration body 12b and the detection electrode portion 2B are joined even after the vibration body portion 1B and the detection electrode portion 2B are joined. Since the positional relationship with the small electrodes 22a1 to 22an can be confirmed by optical means through the transparent substrate 21, the operation of selecting a small electrode at a position suitable for detecting a change in capacitance as a detection electrode Can be performed reliably.
Therefore, by using the configuration of the second embodiment as a countermeasure against the electrode position deviation at the time of alignment (alignment), it becomes possible to detect the capacitance change more accurately than the first embodiment.

  In the third embodiment of the present invention, in addition to the configuration of the first embodiment, a further measure is taken against a position error when aligning both in the joining process of the vibrating body portion and the detection electrode portion. As a fitting portion for suppressing the positional deviation between the vibration body and the detection electrode that occurs when the vibration body portion and the detection electrode portion are joined, the detection electrode portion of the vibration body portion is opposed to the detection electrode portion. A concave portion on the vibrating body portion side having an inner circumferential shape that fits to the outer peripheral shape is formed, and the detection electrode portion is fitted into the concave portion of the vibrating body portion when the vibrating body portion and the detection electrode portion are joined. To align. As a result, in the third embodiment, the positional deviation between the vibrating body and the detection electrode that occurs when the vibrating body portion and the detection electrode portion are joined can be suppressed to be small. Therefore, the vibration that occurs when the vibrating body portion and the detection electrode portion are joined. It is possible to prevent such a problem that the position deviation between the body and the detection electrode becomes too large, and the positions of all the small electrodes constituting the detection electrode are not suitable for the detection of the capacitance change. It becomes possible to reliably increase the detection accuracy of the displacement of the vibrator based on the change in capacitance by selecting one or more small electrodes at positions suitable for detection of the change in capacitance.

7 to 8 show the structure of the MEMS structure according to the third embodiment of the present invention and the manufacturing method thereof. FIG. 7 is a schematic process diagram of the manufacturing method of the MEMS structure according to the third embodiment of the present invention. In FIGS. 7B and 7C, the vibrating body portion 1C and the detection electrode portion 2C are joined. The structure of the MEMS structure 100C is shown. FIG. 8 is a structural diagram of the vibrating body portion 1C. 7 to 8, the same components as those in the conventional configuration example shown in FIG. 12 or the first embodiment described in FIGS. 1 to 5 are denoted by the same reference numerals, and only different portions are shown. explain.
(A) Configuration of vibrating body part in Example 3
FIG. 8A and FIG. 8B are a side sectional view (AA sectional view of FIG. 8B) and a plan view of the vibrating body portion 1C, respectively.
The vibrating body portion 1C (FIG. 8) according to the third embodiment is arranged on the surface of the vibrating body portion 1C facing the detection electrode portion 2C with respect to the vibrating body portion 1A (FIG. 2). It is characterized in that a concave portion 15 having an inner peripheral shape that fits to the outer peripheral shape is formed, and the other points are the same as those of the vibrating body portion 1A (FIG. 2).

That is, in Example 3, in order to suppress positional deviation between the vibrating body 12b and the detection electrodes (a plurality of small electrodes 22a1 to 22an), both are aligned in the joining process of the vibrating body portion 1C and the detection electrode portion 2C ( As a countermeasure against a position error at the time of alignment), a recess 15 having a depth d2 (for example, 1 μm) is formed in the vibrating body 1C by etching. Here, the inner peripheral shape of the concave portion 15 is matched with the outer peripheral shape (for example, 2600 μm □) of the detection electrode portion 2C so that the concave portion 15 of the vibrating body portion 1C and the detection electrode portion 2C can be fitted. .
(B) Configuration of the detection electrode unit in Example 3:
As the detection electrode portion 2C in the third embodiment, one having the same configuration as that of the detection electrode portion 2A in the first embodiment shown in FIG. 3 can be used.
(C) Joining of vibrating body part and detection electrode part in Example 3 FIG. 7A is a side sectional view showing a state before the vibrating body part 1C and the detection electrode part 2C are joined. 7 (b) and FIG. 7 (c) are a side cross-sectional view (cross-sectional view taken along line AA in FIG. 7 (c)) and a plan view showing a state after the vibrating body portion 1C and the detection electrode portion 2C are joined. It is. As shown in FIG. 7, the vibrating body portion 1 </ b> C and the detection electrode portion 2 </ b> C are joined by, for example, anodic bonding to configure the MEMS structure 100 </ b> C shown in FIGS. 7B to 7C.

  In Example 3, as a countermeasure against a position error when aligning both in the bonding process of the vibrating body portion 1C and the detection electrode portion 2C, the vibrating body portion 1C and the detection electrode portion 2C are bonded by a bonder. Before bonding by anodic bonding or the like, as shown in FIG. 7, the detection electrode portion 2C is aligned so as to fit into the recess 15 of the vibrating body portion 1C, thereby aligning in the bonding step. The positional deviation between the vibrating body 12b and the detection electrodes (the plurality of small electrodes 22a1 to 22an) generated during (alignment) can be suppressed.

  In the fourth embodiment of the present invention, in addition to the configuration of the first embodiment, a further measure against a positional error when aligning both in the joining process of the vibrating body portion and the detection electrode portion is taken. As a fitting portion for suppressing the positional deviation between the vibration body and the detection electrode that occurs when the vibration body portion and the detection electrode portion are joined, the vibration body portion side surface of the vibration body portion is opposed to the detection electrode portion. A convex portion (or a concave portion) is formed, and the detection electrode portion side (the concave portion or the convex portion) is fitted to the vibrating body portion side (the convex portion or the concave portion) on the surface facing the vibrating body portion in the detection electrode portion. So that (the convex portion or the concave portion) on the vibration body portion side and the (concave portion or the convex portion) on the detection electrode portion side are fitted when the vibrating body portion and the detection electrode portion are joined. Align it. Thereby, in Example 4, since the position shift of the vibrating body and the detection electrode that occurs when the vibrating body portion and the detection electrode portion are joined can be suppressed to a small value, the vibration that occurs when the vibrating body portion and the detection electrode portion are joined. It is possible to prevent such a problem that the position deviation between the body and the detection electrode becomes too large, and the positions of all the small electrodes constituting the detection electrode are not suitable for the detection of the capacitance change. It becomes possible to reliably increase the detection accuracy of the displacement of the vibrator based on the change in capacitance by selecting one or more small electrodes at positions suitable for detection of the change in capacitance.

9 to 11 show the structure of a MEMS structure and a method for manufacturing the same according to Embodiment 4 of the present invention. FIG. 9 is a schematic process diagram of a method for manufacturing a MEMS structure according to a fourth embodiment of the present invention. In FIGS. 9B to 9C, a vibrating body portion 1D and a detection electrode portion 2D are joined. The structure of the MEMS structure 100D is shown. FIG. 10 is a structural diagram of the vibrating body portion 1D, and FIG. 11 is a structural diagram of the detection electrode portion 2D. 9 to 11, elements having the same functions as those of the conventional configuration example shown in FIG. 12 or the first embodiment described with reference to FIGS. 1 to 5 are denoted by the same reference numerals, and only different portions are shown. explain.
(A) Configuration of vibrating body part in Example 4:
FIG. 10A and FIG. 10B are a side sectional view (AA sectional view of FIG. 10B) and a plan view of the vibrating body portion 1D, respectively.

The vibrating body portion 1D (FIG. 10) in the fourth embodiment has an outer peripheral shape of the convex portion 26 at a position corresponding to the convex portion 26 of the detection electrode portion 2D with respect to the vibrating body portion 1A (FIG. 2) in the first embodiment. The concave portion 16 on the vibrating body portion side having an inner peripheral shape that fits in is formed by etching or the like, and is otherwise the same as the vibrating body portion 1A (FIG. 2).
(B) Configuration of detection electrode unit in Example 4:
FIG. 11A and FIG. 11B are a side sectional view (AA sectional view in FIG. 11B) and a plan view of the detection electrode portion 2D, respectively.
The detection electrode portion 2D (FIG. 11) in the fourth embodiment has an inner peripheral shape of the concave portion 16 at a position corresponding to the concave portion 16 of the vibrating body portion 1D with respect to the detection electrode portion 2A (FIG. 3) in the first embodiment. The protrusion 26 having the outer peripheral shape to be fitted is characterized in that it is formed by film formation or the like, and is otherwise the same as the detection electrode portion 2A (FIG. 3).

(C) Joining of vibrating body part and detection electrode part in Example 4 FIG. 9A is a side sectional view showing a state before joining the vibrating body part 1D and the detection electrode part 2D. 9 (b) and FIG. 9 (c) are a side sectional view (a sectional view taken along line AA in FIG. 9 (c)) and a plan view showing a state after the vibrating body portion 1D and the detection electrode portion 2D are joined. It is. As shown in FIG. 9, the vibrating body portion 1 </ b> D and the detection electrode portion 2 </ b> D are joined by, for example, anodic bonding to configure the MEMS structure 100 </ b> D shown in FIGS.
In Example 4, as a countermeasure against a position error when aligning both in the bonding process of the vibrating body portion 1D and the detection electrode portion 2D, the vibrating body portion 1D and the detection electrode portion 2D are bonded by a bonder. 9 by anodic bonding or the like, as shown in FIG. 9, by positioning so that the concave portion 16 on the vibrating body portion 1D side and the convex portion 26 on the detection electrode portion 2D side are fitted. The positional deviation between the vibrating body 12b and the detection electrodes (the plurality of small electrodes 22a1 to 22an) that occurs during alignment (alignment) in the joining process can be suppressed.

(D) Convex and concave portions for alignment in Example 4:
Each planar shape of the convex portion 26 and the concave portion 16 for alignment in the fourth embodiment may be rectangular as shown in FIGS. 9 to 11 or may be other shapes.
The number of each of the convex part 26 and the concave part 16 is not limited to two shown in FIGS. 9 to 11, and may be more than that, and the convex part 26 and the concave part 16 are fitted. The relative positional relationship on the joint surface between the vibrating body portion 1D and the detection electrode portion 2D is only required to be defined reliably. And when each planar shape of the convex part 26 and the recessed part 16 is shapes other than circular, for example, the rectangle shown by FIGS. 9-11, the number of each of the convex part 26 and the recessed part 16 is one piece. Even if it exists, since the relative positional relationship on the joint surface of vibrating body part 1D and detection electrode part 2D is prescribed | regulated in the state which the convex part 26 and the recessed part 16 fitted, it is applicable.

(D) Another configuration example:
In Example 4, as described above, the concave portion 16 on the vibrating body portion side is formed on the surface facing the detection electrode portion 2D of the vibrating body portion 1D, and the surface facing the vibrating body portion 1D on the detection electrode portion 2D is formed. A convex part 26 on the detection electrode part side that fits into the concave part 16 on the vibration body part side is formed, and when the vibration body part 1D and the detection electrode part 2D are joined, the concave part 16 on the vibration body part side and the detection electrode part are formed. It is set as the structure which aligns so that the convex part 26 of the side may fit. In the present invention, instead of the above-described configuration, a configuration in which the concave portion and the convex portion are reversed on the vibrating body portion side and the detection electrode portion side, that is, the vibrating body portion on the surface facing the detection electrode portion in the vibrating body portion. And forming a concave portion on the detection electrode portion side that fits with the convex portion on the vibration body portion side on the surface of the detection electrode portion facing the vibration body portion, and detecting the vibration body portion and the detection portion. It is good also as a structure which aligns so that the recessed part by the side of a vibrating body part and the convex part by the side of a detection electrode part may fit at the time of joining with an electrode part.
[Application example of MEMS structure]
The MEMS structure according to the present invention has a structure in which a vibrating body (movable electrode) and a detection electrode are opposed to each other with a space therebetween, and changes in the capacitance C1 between the vibrating body (movable electrode) and the detection electrode. It functions as a sensor element to detect, and mechanical quantities such as acceleration and angular velocity can be measured through displacement of the vibrating body detected based on this capacitance change.

(A) Application to an acceleration sensor For example, the MEMS structure 100A having the configuration shown in FIGS. 1B to 1C is used as a sensor element, and a vibrating body 12b (movable electrode) and detection electrodes (a plurality of small electrodes 22a1). An acceleration sensor that is a MEMS device can be configured by providing a capacitance detection circuit that detects a capacitance C1 between the small electrodes selected from ˜22an as a subsequent electronic circuit.
In this acceleration sensor, the vibration body 12b (movable electrode) is displaced in the vertical direction (up and down direction on the paper surface in FIG. 1B) in response to acceleration in the vertical direction (up and down direction on the paper surface in FIG. 1B). The change in the capacitance C1 due to the change in the distance between the vibrating body 12b (movable electrode) and the detection electrode accompanying this displacement is detected by the capacitance detection circuit, and the vibration detected based on the change in capacitance. Through the displacement of the body 12b, the vertical acceleration can be measured.

  Further, in this acceleration sensor, the vibration body 12b (movable electrode) receives the acceleration in the horizontal direction (vertical direction on the paper surface in FIG. 1C) and the vibrating body 12b (movable electrode) in the horizontal direction (vertical direction on the paper surface in FIG. 1C). The capacitance detection circuit detects a change in the capacitance C1 due to a change in the electrode facing area between the vibrating body 12b (movable electrode) and the detection electrode accompanying the displacement, and is detected based on the capacitance change. It is also possible to measure the horizontal acceleration through the displacement of the vibrating body. However, as shown in FIG. 1C, the individual areas of the small electrodes 22a1 to 22an are smaller than the area of the vibrating body 12b. Therefore, in the case of measuring the acceleration in the horizontal direction, as many small electrodes as possible are used. It is preferable to select it as a detection electrode so that the rate of change of the electrode facing area between the vibrating body 12b (movable electrode) and the detection electrode accompanying the horizontal displacement of the vibrating body 12b is sufficiently large.

When detecting the direction of acceleration in the latter horizontal acceleration measurement, the detection electrode unit 2A is provided with a pair of detection electrodes including a plurality of small electrodes 22a1 to 22an, and the displacement of the vibrating body 12b (movable electrode) is detected. The pair of detection electrodes are arranged so as to be distributed on both sides of the reference position of the vibrating body 12b (movable electrode) along the direction (vertical direction on the paper surface of FIG. 1C), and each detection electrode and the vibrating body 12b are arranged. A configuration is adopted in which a change in electrostatic capacitance with each (movable electrode) is detected.
(B) Application to an angular velocity sensor Further, for example, a MEMS structure 100A having the configuration shown in FIGS. 1B to 1C is used as a sensor element, and a vibrating body 12b (movable electrode) and detection electrodes (a plurality of small electrodes) And a capacitance detection circuit for detecting a capacitance C1 between the electrodes 12a1 to 22an) and an electrode surface facing the vibration member 12b or the side surface of the beam 12a with a gap therebetween. An angular velocity sensor, which is a MEMS device, can be configured by arranging a pair of drive electrodes (not shown) provided with both sides of the vibrating body 12b or the beam 12a (upper and lower sides in the drawing of FIG. 1C). it can.

In this angular velocity sensor, when an AC voltage drive signal is applied to the drive electrode, the vibrating body 12b (movable electrode) is forcibly vibrated in a horizontal direction (vertical direction in the plane of FIG. 1C) at a fixed frequency. At this time, when an angular velocity about the vibrating body 12b (movable electrode) and the beam 12a is applied, the direction in which the vibrating body 12b (movable electrode) is orthogonal to the forced vibration direction (the depth direction in FIG. 1C). That is, starting with Coriolis vibration proportional to the angular velocity in the vertical direction on the paper surface of FIG. 1B, a vibrating body 12b (movable electrode) and a detection electrode (small electrode selected from a plurality of small electrodes 22a1 to 22an) The capacitance C1 changes due to the change in the inter-electrode distance. The change in the capacitance C1 can be detected by a capacitance detection circuit, and the angular velocity can be measured through the displacement of the vibrating body detected based on the change in capacitance.
(C) As described above, the MEMS structure of the present invention can suppress the positional deviation between the vibration body and the detection electrode that occurs when the vibration body section and the detection electrode section are joined. Since the detection accuracy of the displacement of the vibrating body based on the capacitance change can be further increased, by using such a MEMS structure of the present invention as a sensor element of a mechanical quantity sensor such as an acceleration sensor or an angular velocity sensor, The measurement accuracy of the mechanical quantity sensor can be further improved.

1, 1A, 1B, 1C, 1D ... vibrating body part 11 ... support structure part, 12 ... movable part, 12a ... beam, 12b ... vibrating body, 13 ... gap, 14 ... Recesses, 15 ... Recesses, 16 ... Recesses 2, 2A, 2B, 2C, 2D ... Detection electrodes 21 ... Substrate, 22a ... Detection electrodes, 22a1 to 22a5 ... Small electrode, 22b ... detection electrode wiring, 22b1-22b5 ... small electrode wiring, 22c ... detection electrode connection pad, 22c1-22c5 ... small electrode connection pad, 23a ... movable Electrode connection pads 26... Convex portions L 1 a, L 1 b, L 2 a, L 2 b ... misregistration amounts 100, 100 A, 100 B, 100 C, 100 D... MEMS structure 200. Switch circuit, 232 ... Switch system Circuit, 233 ... operational amplifier, 234 ... AC signal generator, 235 ... feedback resistor, SW1 to SW5 ... switch

Claims (11)

A vibrating body portion comprising a supporting structure portion and a vibrating body supported to be displaceable with respect to the support structure portion;
A detection electrode unit comprising a substrate and a detection electrode formed on the substrate;
The vibrating body portion and the detection electrode portion are joined such that the vibrating body and the detection electrode face each other with a space therebetween, and a change in capacitance between the vibrating body and the detection electrode is detected. In a structured MEMS structure,
The detection electrode is composed of a plurality of small electrodes separated from each other,
One or more small electrodes can be selected in accordance with the positional deviation between the vibrating body and the detection electrode when the vibrating body and the detection electrode are joined. MEMS structure. By the substrate being made of a transparent plate member,
When the vibrating body portion and the detection electrode portion are joined, the relative position of each small electrode with respect to the vibrating body can be optically confirmed from the outside on the anti-vibrating body portion side. Item 4. The MEMS structure according to Item 1. The MEMS structure according to claim 1, further comprising a fitting portion for suppressing a positional deviation between the vibration body and the detection electrode that occurs when the vibration body section and the detection electrode section are joined. The concave portion on the vibrating body portion side having an inner peripheral shape that fits the outer peripheral shape of the detection electrode portion is formed on the surface of the vibrating body portion facing the detection electrode portion as the fitting portion. 4. The MEMS structure according to 3. As the fitting portion, a convex portion (or a concave portion) on the vibration body portion side is formed on the surface of the vibration body portion facing the detection electrode portion, and the vibration body portion is formed on the surface of the detection electrode portion facing the vibration body portion. The MEMS structure according to claim 3, wherein a concave portion (or convex portion) on the detection electrode portion side that fits with the convex portion (or concave portion) on the side is formed. A MEMS device using the MEMS structure according to any one of claims 1 to 5,
By providing a switch circuit to which the small electrodes are connected,
One or more small electrodes can be selected by the switch circuit in accordance with the positional deviation between the vibrating body and the detection electrode when the vibrating body and the detection electrode are joined. The MEMS device characterized by the above-mentioned. A vibrating body portion comprising a supporting structure portion and a vibrating body supported to be displaceable with respect to the support structure portion;
A detection electrode unit comprising a substrate and a detection electrode formed on the substrate;
The vibrating body portion and the detection electrode portion are joined such that the vibrating body and the detection electrode face each other with a space therebetween, and a change in capacitance between the vibrating body and the detection electrode is detected. In the manufacturing method of the MEMS device using the made MEMS structure,
The detection electrode is composed of a plurality of small electrodes separated from each other, and a switch circuit to which the small electrodes are connected is provided.
One or more small electrodes are selected by the switch circuit in response to a positional shift between the vibrating body and the detection electrode in a state where the vibrating body and the detection electrode are joined. Manufacturing method of a MEMS device. The substrate is composed of a transparent plate member,
The relative position of each small electrode with respect to the vibrating body is optically confirmed from the outside on the anti-vibrating body side when the vibrating body section and the detection electrode section are joined. Manufacturing method of a MEMS device. A fitting portion is provided to suppress a positional deviation between the vibrating body and the detection electrode that occurs when the vibrating body portion and the detection electrode section are joined.
The method for manufacturing a MEMS device according to claim 7, wherein positioning is performed so that the fitting portion is fitted when the vibrating body portion and the detection electrode portion are joined. As the fitting portion, on the surface of the vibrating body portion facing the detection electrode portion, a concave portion on the vibrating body portion side having an inner circumferential shape fitted to the outer circumferential shape of the detection electrode portion is formed,
The method of manufacturing a MEMS device according to claim 9, wherein when the vibrating body portion and the detection electrode portion are joined, the detection electrode portion and the concave portion on the vibrating body portion side are fitted so as to be aligned. . As the fitting portion, a convex portion (or a concave portion) on the vibration body portion side is formed on the surface of the vibration body portion facing the detection electrode portion, and the vibration body portion is formed on the surface of the detection electrode portion facing the vibration body portion. Forming a concave part (or convex part) on the detection electrode part side to be fitted to the convex part (or concave part) on the side,
At the time of joining the vibrating body part and the detection electrode part, the convex part (or concave part) on the vibrating body part side and the concave part (or convex part) on the detection electrode part side are fitted and aligned. A method for manufacturing a MEMS device according to claim 9.

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