JPH0832090A - Inertia force sensor and manufacture thereof - Google Patents

Abstract

PURPOSE:To lessen a residual strain, which is generated at the time of manufacture of an inertia force sensor, by a method wherein a substrate and a wafer having the face (110) are bonded together to form the substrate into a substrate constituted of two layers and the wafer is subjected to anisotropic etching to form a structure having vibrating bodies and fixed electrodes. CONSTITUTION:In a structure, a wafer, whose surface crystal face bonded on a substrate 9 via an insulating film is the face (110) and which consists of a single crystal silicon film, is subjected to anisotropic etching. Electrodes are respectively formed on the surfaces of vibrating bodies. Thereby, a mass body 4 constitutes a movable electrode, which can be displaced between fixed electrodes 6 and 7. The side crystal faces of the structure are respectively constituted of the faces (111) which are formed vertically to the surface crystal face (110) of the wafer. The metal electrodes 8, a metal electrode 8 and a metal electrode 8 are respectively formed on the surfaces of the vibrating bodies, the electrode 6 and the electrode 7. Beams 3 of the vibrating bodies and mass body 4 have a gap between the substrate 9 and them and anchors 5 are bonded on the substrate 9. Thereby, a residual strain, which is generated at the time of manufacture of an inertia force sensor, can be lessened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inertial force sensor for detecting an inertial force such as acceleration and angular velocity used for vibration measurement, vehicle control and motion control, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Inertial force sensors for detecting acceleration or angular velocity applied to a moving object include piezoelectric type, strain gauge type, magnetic type utilizing a differential transformer, and capacitive type detecting a capacitance change of a capacitor. There are various types.
In recent years, especially as an inertial force sensor that applies semiconductor micromachining technology, an acceleration sensor that uses the piezoresistive effect that changes the electrical resistance due to external mechanical force, and an acceleration that calculates the acceleration by detecting the change in the capacitance of the capacitor. Sensors and angular velocity sensors have received much attention. These have advantages such as miniaturization, mass productivity, high accuracy, and high reliability of the device. In particular, for an acceleration sensor that electrically detects acceleration from changes in the capacitance of a capacitor, see CAPASITIVE ACCELEROMET.
ER WITH HIGHLY SYMMETRICA
L DESIGN, SENSORS & ACTUAT
The technique is described in ORS, A21-A23 (1990) 312-315, and this technique will be described below with reference to FIG. Further, as an angular velocity sensor for electrically detecting the angular velocity of a rotating object from a change in the capacitance of a capacitor, Japanese Patent Application Laid-Open No. 62-93668 and U.S. Pat.
0364 etc.

A conventional technique will be described. FIG. 19 shows CAP.
ASITIVE ACCELEROMETER WIT
H HIGHLY SYMMETRICAL DESI
GN, SENSORS & ACTUATORS, A2
FIG. 19 is a plan view (FIG. 19A) and a cross-sectional view taken along line GG (FIG. 19B) of the acceleration sensor described in 1-A23 (1990) 312-315. In FIG. 19, 3 is a beam,
4 is a mass body, 6 and 7 are fixed electrodes, 55 is a silicon substrate having the beam 3 and the mass body 4, and 56 and 57 are glass substrates. The configuration and operation of this acceleration sensor will be described. This acceleration sensor is formed by etching, a silicon substrate 55 composed of a beam 3 and a mass body 4 formed by forming a cavity, a glass substrate 56 having a fixed electrode 6 attached to the surface of a groove formed by etching, and formed by etching. The glass substrate 57 has the fixed electrode 7 attached to the surface of the groove. By forming electrodes on the mass body 4 of the silicon substrate 55, the fixed electrode 6 and the mass body 4,
The fixed electrode 7 and the mass body 4 form two capacitors. By appropriately reducing the thickness of the beam 3 of the silicon substrate 55 with respect to its width, the mass body 4 of the silicon substrate 55 of the present acceleration sensor vibrates in the vertical direction when receiving acceleration in the z-axis direction. At this time, the acceleration is calculated from the change in the capacitance of the capacitor due to the displacement of the mass body 4.

In this acceleration sensor, a silicon substrate 55 having a beam 3 formed by forming a cavity by etching and a mass body 4, and a glass having a fixed electrode attached to the surface of a groove formed by etching. Board 56
After manufacturing the glass substrate 57 and the glass substrate 57 independently,
The manufacturing process of joining these three is taken. Further, when the beam 3 is formed on the silicon substrate 55, the portion where the beam 3 is formed is doped with a very high concentration of p-type impurities. As a result, the etching rate of the portion doped with the p-type impurity decreases. Therefore, if an etching process is performed after doping the portion where the beam 3 is to be formed with a very high concentration of p-type impurities, the etching proceeds to a portion other than the portion where the beam 3 is formed, and thus the beam 3 is formed.
Is formed.

[0005]

SUMMARY OF THE INVENTION The acceleration sensor described above has a capacitance of a capacitor formed between the mass body 4 and the fixed electrode 6 and between the mass body 4 and the fixed electrode 7 due to displacement of the mass body 4 due to acceleration. It uses a method to detect changes.
Therefore, when the glass substrate 56, the glass substrate 57, and the silicon substrate 55 are bonded to each other, a residual strain is generated, which causes a problem that the electrode interval is different from the designed value.
Another problem is that the characteristics of the acceleration sensor change as the electrode spacing changes according to temperature changes.

Further, in the step of manufacturing the beam 3 of the silicon substrate 55, p-type impurities are added to the beam 3 of the silicon substrate 55 completed in order to perform the doping of the beam 3 with a very high concentration of the p-type impurity. Causes residual strain. Therefore, the rigidity of the beam 3 is increased, and the sensitivity (displacement amount per 1 G:
However, G has a problem that gravitational acceleration decreases. Further, the characteristics of the sensor fluctuate due to the fluctuation of the residual strain, which causes a problem in terms of long-term reliability.

[0007]

The present invention is manufactured by utilizing a technique (bulk micromachining technique) in which an element constituting an inertial force sensor is produced by etching from a substrate and a wafer which are bonded in advance. The present invention relates to an inertial force sensor. The inertial force sensor according to claim 1 is manufactured by etching a substrate and a wafer that is bonded to the substrate and is made of single crystal silicon having a (110) plane along the (111) plane direction. A structural body, the structural body includes a mass body positioned with a gap with respect to the substrate, a beam supporting the mass body and positioned with a gap with respect to the substrate, and the beam. And a fixed electrode on the side surface of the mass body.

An inertial force sensor according to a second aspect of the present invention has a structure in which the beam and the mass body have a shape that is rotationally symmetrical by 180 degrees within the wafer plane.

In the inertial force sensor according to the third aspect of the present invention, the shape of the mass body is a parallelogram.

In the inertial force sensor according to the fourth aspect of the present invention, the mass body has a parallelogram shape, and one end of the beam has a structure positioned on the acute angle side of the parallelogram mass body. .

An inertial force sensor according to a fifth aspect of the present invention has a structure in which the dimension of the beam with respect to the vibration direction of the mass body is smaller than the dimension of the beam in other directions.

The inertial force sensor according to the sixth aspect is provided with a damping adjusting mechanism for adjusting the vibration characteristics of the mass body.

An inertial force sensor according to a seventh aspect of the present invention is such that at least one side of the mass body is comb-shaped, and a comb-shaped damping adjusting mechanism facing the comb-shaped portion is provided.

In the inertial force sensor according to the eighth aspect of the present invention, at least one side of the mass body is comb-shaped, and a comb-shaped fixed electrode facing the comb-shaped portion is provided.

The inertial force sensor according to a ninth aspect is provided with a stopper for limiting the displacement of the mass body.

The inertial force sensor according to claim 10 is:
At least one side of the mass body is comb-shaped, and a comb-shaped stopper facing the comb-shaped portion is provided.

The inertial force sensor according to claim 11 is
It is a hollowed out part near the center of the mass body.

The inertial force sensor according to claim 12 is
A beam and an anchor are provided in a hollow portion of a mass body having a hollowed-out shape near the center.

The inertial force sensor according to claim 13 is
The actuating electrode is provided around the hollow portion of the mass body having a hollowed-out shape near the center or around the vibrating body.

The inertial force sensor according to claim 14 is
An IC detection circuit for detecting acceleration is provided on the wafer for forming a structure.

The inertial force sensor according to claim 15 is:
An IC detection circuit for detecting acceleration is provided on the structure.

The inertial force sensor according to claim 16 is
An auxiliary support part is provided around the structure, and a protective substrate for sealing the structure is provided on the auxiliary support part.

The inertial force sensor according to claim 17 is
At least two inertial force sensors having different detection directions are incorporated on the same substrate.

The inertial force sensor according to claim 18 is
A substrate provided with two lower fixed electrodes and a structure formed by etching a wafer made of single crystal silicon having a (110) plane and bonded to the substrate along the (111) plane direction. The structure includes two mass bodies positioned above the two lower fixed electrodes with a gap,
A vibrating body having a beam that supports the mass body and is positioned with a gap from the substrate, and an anchor that supports the beam and is bonded to the substrate; and a vibrator provided outside the mass body.
One fixed electrode and a drive electrode located between the two mass bodies.

The inertial force sensor according to claim 19 is
The shape formed by the beam and the mass body is such that it has rotational symmetry of 180 degrees in the plane of the wafer.

The inertial force sensor according to claim 20 is:
The shape of the mass body is a parallelogram.

The inertial force sensor according to claim 21 is
The mass body has a parallelogram shape, and one end of the beam has a structure positioned on the acute angle side of the parallelogram mass body.

The inertial force sensor according to claim 22 is
It is a hollowed out part near the center of the mass body.

The inertial force sensor according to claim 23 is
An IC detection circuit for detecting an angular velocity is provided on the wafer for forming a structure.

The inertial force sensor according to claim 24 is
An IC detection circuit for detecting an angular velocity is provided on the structure.

The inertial force sensor according to claim 25 is
An auxiliary support part is provided around the structure, and a protective substrate for sealing the structure is provided on the auxiliary support part.

The inertial force sensor according to claim 26 is
At least two inertial force sensors having different detection directions are incorporated on the same substrate.

A method of manufacturing an inertial force sensor according to claim 27 includes the following steps (1) to (5). (1) The substrate having the first insulating film deposited on the surface thereof and the wafer of single crystal silicon having the crystal surface of the surface having the second insulating film deposited on the (110) surface are formed of the first insulating film. After forming an etching groove on the surface of the film or on the surface of the second insulating film, bonding the surfaces having the insulating film to each other so as to face each other. (2) The back surface of the surface having the second insulating film of the wafer Polishing step (3) A third insulating film is deposited on the back surface of the surface of the wafer having the second insulating film, and etching is performed to obtain a desired pattern on the third insulating film. After removing the third insulating film, anisotropic etching is performed along the (111) plane direction of the wafer up to the boundary between the wafer and the second insulating film, whereby the vibrating body is formed. , The fixed electrode and the (4) A step of releasing the mass body and the beam by removing the second insulating film exposed by etching the wafer in the step (3) by etching (5) Step of selectively metallizing a metal electrode on the vibrating body and the fixed electrode

A method of manufacturing an inertial force sensor according to claim 28 includes the following steps (1) to (4). (1) A substrate having a first insulating film deposited on the surface thereof, and a crystal plane of the surface having a (110) plane and at least one etching groove, and a second insulating film on the surface having the etching groove. Bonding a film-deposited wafer made of single crystal silicon so that the surfaces having the insulating film face each other (2) depositing a third insulating film on the back surface of the surface having the second insulating film of the wafer Then, after removing the unnecessary third insulating film by etching to obtain a desired pattern on the third insulating film, anisotropic etching is performed along the (111) plane direction of the wafer. Etching the wafer to the boundary between the wafer and the second insulating film to form the structure including the vibrating body and the fixed electrode. (3) The wafer was etched in the step (2). Exposed by Step of selecting metallized metal electrode on said mass body and said step of releasing the beam (4) the vibrator and the fixed electrode by removing by etching the second insulating film

A method for manufacturing an inertial force sensor according to claim 29 includes the following steps (1) to (3). (1) The substrate and the crystal plane of the surface are (110) planes,
And a step of bonding a wafer made of single crystal silicon having at least one etching groove so that the etching groove and the substrate face each other (2) depositing an insulating film on the back surface of the bonding surface of the wafer,
After removing the unnecessary insulating film by using etching in order to obtain a desired pattern in the insulating film, anisotropic etching is performed along the (111) plane of the wafer to form the vibrator. And (3) a step of selectively metallizing a metal electrode on the fixed electrode and the vibrating body.

A method of manufacturing an inertial force sensor according to claim 30 includes the following steps (1) to (5). (1) A substrate having a lower fixed electrode attached to the surface via a first insulating film, and a wafer made of single crystal silicon having a (110) crystal face on which a second insulating film is deposited. After forming an etching groove on the surface of the second insulating film, bonding the lower fixed electrode and the etching groove so as to face each other. (2) A back surface of the surface of the wafer having the second insulating film is formed. Step of polishing (3) A third insulating film is deposited on the back surface of the surface of the wafer having the second insulating film, and an unnecessary third film is formed on the surface by etching to obtain a desired pattern. After removing the insulating film, etching is performed to the boundary between the wafer and the second insulating film along the (111) plane direction of the wafer by using anisotropic etching, whereby the vibrating body and the fixed electrode are formed. And the drive electrode (4) The second insulating film exposed by etching the wafer in step (3) is removed by etching to remove the mass and the beam. And (5) a step of selectively metallizing a metal electrode on the vibrating body, the fixed electrode, and the drive electrode.

A method for manufacturing an inertial force sensor according to claim 31 includes the following steps (1) to (5). (1) A substrate having a lower fixed electrode attached to the surface thereof via a first insulating film, and a crystal plane of the surface having a (110) plane and having at least one etching groove, and a surface having the etching groove. A step of joining a wafer made of single crystal silicon having a second insulating film deposited thereon so that the lower fixed electrode and the etching groove face each other (2) Step 3 of polishing the back surface. (3) Depositing a third insulating film on the back surface of the surface of the wafer having the second insulating film, and using etching to obtain a desired pattern on the surface. After removing the third insulating film, anisotropic etching is used to etch along the (111) plane direction of the wafer to the boundary between the wafer and the second insulating film. Fixed electrode, (4) A step of forming the structure having a drive electrode (4) The second insulating film exposed by etching the wafer in the step (3) is removed by etching to remove the mass. Step of releasing the body and the beam (5) Step of selectively metallizing a metal electrode on the vibrating body, the fixed electrode, and the drive electrode

A method for manufacturing an inertial force sensor according to claim 32 includes the following steps (1) to (4). (1) A substrate having a lower fixed electrode attached to the surface thereof, and a single crystal silicon wafer having a crystal plane on the surface of which is a (110) plane and having at least one etching groove, the lower fixed electrode electrode and the etching Bonding so that the grooves face each other (2) Polishing the back surface of the bonding surface of the wafer (3) Depositing an insulating film on the back surface of the bonding surface of the wafer,
The vibrator is formed by removing the insulating film by etching to obtain a desired pattern on the surface and then etching the wafer along the (111) plane direction of the wafer by anisotropic etching. And a step of producing the structure including the fixed electrode and the drive electrode. (4) A step of selectively metallizing a metal electrode on the vibrating body, the fixed electrode, and the drive electrode.

[0039]

The inertial force sensor according to the first aspect of the present invention includes a substrate and (1
10) An inertial force sensor is used in order to form a structure having a vibrating body and a fixed electrode by anisotropically etching a wafer with respect to what is formed of two layers by joining a wafer having a surface. It is possible to reduce the residual strain that occurs during manufacturing.

In the inertial force sensor according to the second aspect of the present invention, the beam and the mass body are formed so that the shape formed by the beam and the mass body is rotationally symmetrical with respect to each other by 180 degrees in the wafer plane. Therefore, the amount by which the mass body can be displaced can be increased, so that the change in the capacitance of the capacitor formed by the mass body and the fixed electrode can be increased.

In the inertial force sensor according to the third aspect of the present invention, the shape of the mass body is a parallelogram, so that the side surface of the mass body is formed of the (111) plane perpendicular to the (110) plane. Guarantee.

In the inertial force sensor according to the fourth aspect, the mass body has a parallelogram shape, and one end of the beam is provided on the acute angle side of the parallelogram mass body. It is guaranteed that the side surface near the boundary between the mass body and the beam formed by etching the wafer is formed only by the (111) plane perpendicular to the crystal plane (110) plane.

The inertial force sensor according to the fifth aspect of the invention has a structure in which the dimension of the beam with respect to the vibration direction of the mass body is smaller than the dimension of the beam in the other directions, so that the sensitivity in the specific direction is increased. Is improved.

The inertial force sensor according to the sixth or seventh aspect is to improve the frequency characteristic of the inertial force sensor by providing a damping adjusting mechanism for adjusting the vibration characteristic of the mass body. Is possible.

In the inertial force sensor according to the eighth aspect, the frequency characteristic of the inertial force sensor can be improved and the capacitance of the capacitor in the inertial force sensor can be increased by providing the comb-shaped fixed electrode. Is possible.

The inertial force sensor according to the ninth or tenth aspect is provided with a stopper for limiting the displacement of the mass body, so that an excessive displacement of the mass body exerts an excessive force on the beam of the vibrating body. It is possible to protect the vibrating body from damage due to stress. Further, it becomes possible to prevent adsorption between the mass body and the fixed electrode.

The inertial force sensor according to claim 11 is:
By hollowing out the vicinity of the center of the mass body, it is possible to adjust the mass of the mass body according to the size of the hollowed body, and thus it is possible to adjust the frequency characteristic of the inertial force sensor.

The inertial force sensor according to claim 12 is
By providing the beam and the anchor in the hollow portion of the mass body having a hollowed-out shape near the center, the inertial force sensor becomes smaller. Further, it is possible to avoid the stress generated when the materials of the wafer and the substrate are different.

The inertial force sensor according to claim 13 is:
The inertial force sensor can be provided with a self-diagnosis function by providing an actuating electrode around the hollow part of the mass body having a hollowed-out shape near the center or around the vibrating body.

The inertial force sensor according to claim 14 is:
The inertial force sensor can be downsized by providing an IC detection circuit for detecting acceleration on the wafer for forming the structure.

The inertial force sensor according to claim 15 is:
By providing an IC detection circuit for detecting acceleration on the structure, the inertial force sensor can be downsized.

The inertial force sensor according to claim 16 is:
By providing the auxiliary support portion around the structure and the protective substrate for sealing the structure on the auxiliary support portion, the cost of the package can be reduced.

The inertial force sensor according to claim 17 is
By incorporating at least two inertial force sensors having different detection directions on the same substrate, an inertial force sensor capable of detecting the acceleration of a moving object by dividing it into at least two components is realized.

The inertial force sensor according to claim 18 is
A substrate provided with two lower fixed electrodes and a structure formed by etching a wafer made of single crystal silicon having a (110) plane and bonded to the substrate along the (111) plane direction. The structure includes two mass bodies positioned above the two lower fixed electrodes with a gap,
A vibrating body having a beam that supports the mass body and is positioned with a gap from the substrate, and an anchor that supports the beam and is bonded to the substrate; and a vibrator provided outside the mass body.
By providing one fixed electrode and the drive electrode located between the two mass bodies, it becomes possible to realize an inertial force sensor that detects an angular velocity from the Coriolis force generated by the rotational movement.

The inertial force sensor according to claim 19 is
Since the shape of the beam and the mass body is configured to have rotational symmetry of 180 degrees in the plane of the wafer, the displacement of the mass body is translated, so that the amount of displacement of the mass body can be increased. Therefore, the change in the electrostatic capacitance of the capacitor formed by the mass body and the fixed electrode can be increased.

The inertial force sensor according to claim 20 is:
The parallelogram shape of the mass body ensures that the side surface of the mass body is formed by the (111) plane perpendicular to the (110) plane.

The inertial force sensor according to claim 21 is
The mass has a parallelogram shape, and one end of the beam has a structure in which one end of the beam is located on the acute angle side of the parallelogram mass, so that the boundary between the mass and the beam formed by etching the wafer. It is guaranteed that the side surface in the vicinity is formed only by the (111) plane perpendicular to the crystal plane (110) plane.

The inertial force sensor according to claim 22 is
By hollowing out the vicinity of the center of the mass body, it is possible to adjust the mass of the mass body according to the size of the hollowed body, and thus it is possible to adjust the frequency characteristic of the inertial force sensor.

The inertial force sensor according to claim 23 is
The inertial force sensor can be downsized by providing an IC detection circuit for detecting the angular velocity on the wafer for forming the structure.

The inertial force sensor according to claim 24 is
The inertial force sensor can be downsized by providing an IC detection circuit for detecting the angular velocity on the structure.

The inertial force sensor according to claim 25 is:
By providing the auxiliary support portion around the structure and the protective substrate for sealing the structure on the auxiliary support portion, the cost of the package can be reduced.

The inertial force sensor according to claim 26 is
By incorporating at least two inertial force sensors having different detection directions on the same substrate, an inertial force sensor capable of detecting the angular velocity of a moving object by dividing it into at least two components is realized.

With the method for manufacturing an inertial force sensor according to any one of claims 27 to 28, high sensitivity,
It is possible to provide a highly reliable inertial force sensor.

[0064]

【Example】

Example 1. FIG. 1 shows the configuration of an embodiment of an acceleration sensor for detecting the acceleration of a linearly moving object according to the present invention. 1A is a plan view of the acceleration sensor, FIG. 1B is a sectional view taken along line AA, and FIG. 1B is a view taken along line BB of FIG. FIG.

In FIG. 1, 3 is a beam, 4 is a mass body, 5 is an anchor, 6 is a fixed electrode, 7 is a fixed electrode, 8 is a metal electrode, and 9 is a substrate made of silicon. Beam 3, mass 4
The anchor 5 is integrally formed to form a vibrating body.
Further, the vibrating body, the fixed electrode 6, and the fixed electrode 7 form a structure. The structure is formed by anisotropically etching a wafer made of single crystal silicon whose surface has a crystal plane of (110) and is bonded to the substrate 9 via an insulating film.
Electrodes are formed on the vibrating body. This makes the mass 4
Constitutes a movable electrode capable of being displaced between the fixed electrode 6 and the fixed electrode 7. The crystal plane on the side surface of the structure is composed of the (111) plane which is perpendicular to the crystal plane (110) plane of the surface of the wafer. Metal electrodes 8 are formed on the surfaces of the vibrating body, the fixed electrode 6 and the fixed electrode 7. The beam 3 and the mass body 4 of the vibrating body have a gap of, for example, about 2 μm to 3 μm with respect to the substrate 9, and the anchor 5
Are bonded to the substrate 9.

In order to increase the sensitivity of the acceleration sensor, it is desirable to increase only the sensitivity in a specific direction (the y direction in the first embodiment). In order to realize this, the sensitivity in the specific direction may be designed to be sufficiently higher than the sensitivity in other directions. Therefore, the beam 3 has a high aspect ratio (for example, w /
It has a structure of t <0.1). When an equal inertial force is applied to each of the x-axis, the y-axis, and the z-axis by making the beam 3 have a high aspect structure, the displacement of the mass body 4 in the z-axis direction is several tens of the displacement in the y-axis direction. It is possible to design twice as small (for example, 1/50 or less), and the sensitivity in the z-axis direction can be designed to be extremely low. Also,
The displacement in the x-axis direction is defined by the compression mode or the tension mode of the beam 3 and can be made smaller than the bending mode in the z-axis direction, so that it is possible to design the displacement smaller than the displacement in the z-axis direction.

The mass body 4 has a parallelogram shape and its acute angle is 70.53 degrees and its obtuse angle is 109.47 degrees. Such an angle is obtained because anisotropic etching is performed so that the crystal planes of the side surfaces of the structure to be formed on the wafer are formed by the (111) plane perpendicular to the (110) plane. is there.

Next, the operation of the acceleration sensor shown in FIG. 1 will be described with reference to FIG. In FIG. 2, 10 and 11 are capacitors formed by the mass body 4 and the fixed electrode 7, and the mass body 4 and the fixed electrode 6, and 12 is an AC signal source, 1
3 is an inverting amplifier, 14 is a capacitor 10 and a capacitor 1.
1 is an acceleration sensor element, 15 is a charge amplifier, 16 is a demodulator such as a synchronous detector, and 17 is a filter including an LPF. Now, assume that an external force is applied in the positive direction of the y-axis. At this time, since the acceleration sensor receives an inertial force in the negative y-axis direction, the mass body 4 is displaced in the negative y-axis direction. Since electrodes are formed on the mass body 4, the mass body 4 can be regarded as a movable electrode. Due to this displacement of the mass body 4, the capacitance of the capacitor formed by the mass body 4 and the fixed electrode 6 and the fixed electrode 7 changes as compared with before the inertial force is applied. This state is shown in FIG. 2 (a), and FIG. 2 (b) shows that in which FIG. 2 (a) is replaced with capacitors 10 and 11. An example of a detection circuit for detecting acceleration using the acceleration sensor element 14 is shown in FIG.
Examples of the detection circuit include a circuit for examining a change in oscillation frequency, a circuit for extracting an impedance change due to a capacitance change in a capacitor, and a circuit for converting a differential amount of electrification and accumulation into a voltage. Here, a configuration of a circuit that measures an impedance change due to a capacitance change of a capacitor due to a displacement of the mass body 4 and calculates an acceleration from the measured value will be described.

FIG. 2C shows an example of the above detection circuit.
A fixed electrode 6 by an AC signal source 12 and an inverting amplifier 13,
Voltages with inverted phases are applied to the fixed electrode 7 and the fixed electrode 7, respectively.
The sum of the electrode distance between the fixed electrode 6 and the mass body 4 and the electrode distance between the fixed electrode 7 and the mass body 4 is 2d, and the displacement of the mass body 4 from the equilibrium state (the state in which no external force is applied) is Δd. Then, the differential capacitance ΔC and the current I flowing through the mass body 4 are expressed by the following equations. ΔC ≈ 2C0 × Δd / d (when Δd << d) ・ ・ ・ (1) I = jω × ΔC × V (2) where C0: fixed electrode 6 or fixed electrode 7 in equilibrium state
Capacitance of the capacitor formed by the mass body 4 I: current flowing in the mass body 4 V: voltage of the AC signal source 12 ω: angular frequency of the AC signal source t t: time charge amplifier 15 Is detected and converted into a voltage. This is demodulated by a demodulator 16 including a synchronous detector in the subsequent stage. After this, LP
2 due to displacement of the mass body 4 through the filter 17 such as F
It outputs a voltage signal proportional to the change in the differential capacitance of two capacitors. Since the differential capacitance changes in accordance with the acceleration as described above, the acceleration sensor of the present invention is configured to detect the acceleration based on the voltage signal output according to the change in the differential capacitance. Further, since the beam 3 and the mass body 4 have a shape such that they have rotational symmetry of 180 degrees in the wafer plane, the mass body 4 can be displaced in parallel to the inertial force in the y-axis direction. By displacing the mass body 4 in parallel, the amount of displacement of the mass body 4 can be increased, so that the capacitance change of the capacitor formed by the mass body 4 and the fixed electrodes 6 and 7 can be increased. be able to.

A method of manufacturing the acceleration sensor of the first embodiment will be described with reference to FIG. In FIG. 3, 18 and 19 are oxide films, 20 is single crystal silicon, and has a crystal plane of (11
A device wafer having a (0) plane, 21 is an etching groove,
22 and 23 are passivation films made of an oxide film or a nitride film, 24 is a p-type or n-type impurity diffusion layer, 25 is a detection circuit IC for detecting acceleration, 26
Is a silicon IC substrate for incorporating the detection circuit IC 25, and 27 is a bonding wire. First, after depositing an oxide film 18 having a thickness of about 3 μm on the device wafer 20, a pattern is formed on the oxide film 18 using a semiconductor lithography technique. Thereafter, dry etching or wet etching is performed to form an etching groove 21 having a depth of about 2 μm to 3 μm from the surface of the oxide film 18. Further, since the etching groove 21 is for freely vibrating the completed mass body 4 and the beam 3, the substrate 9
An etching groove 21 may be provided on the upper oxide film 19. Thereafter, the device wafer 20 and the substrate 9 on which the oxide film 19 is deposited are fusion bonded (fusion bonding).
The two are joined by using a technique (FIG. 3 (a)).

Next, the surface of the device wafer 20 is polished to adjust the thickness of the device wafer 20 to a desired thickness (FIG. 3 (b)). After that, in order to protect the surface of the device wafer 20, the passivation film 22 and the substrate 9 are formed.
The passivation film 23 to protect the surface of the
It is formed on the surface of the device wafer 20 and the substrate 9 by the D method (LPCVD, PECVD, etc.) or the sputtering method. After that, a plan view pattern of a structure forming the acceleration sensor is formed on the surface of the passivation film 22 by dry etching (eg, reactive ion etching (RIE)).

However, when the pattern of the acceleration sensor is formed on the surface of the passivation film 22, the device wafer 2
It is necessary to take the crystal plane orientation of 0 into consideration. This is because the progress of the vertical etching is faster than the progress of the horizontal etching when the device wafer 20 is subjected to the etching process, and after the etching process is completed,
If a vertical or near-vertical cross-sectional shape is obtained, the gap between the electrode surfaces formed by the fixed electrode 6 formed by the device wafer 20 and the mass body 4, and the fixed electrode 7 and the mass body 4.
This is because the gap between the electrode surfaces formed by and can be suppressed, and the electrode surfaces formed by etching are both perpendicular to the surface of the device wafer 20.

The progress of the etching in the vertical direction is faster than the progress of the etching in the lateral direction, and after the etching process is completed, a cross-sectional shape perpendicular to the surface of the device wafer 20 is obtained. The method is called anisotropic etching. The crystal plane of the surface is (11
When the single crystal silicon of (0) is etched, the side crystal faces formed by the permeation of the etching solution are (11
It is known that when etching is performed so as to form a (111) plane that is perpendicular to the (0) plane, it is possible to considerably suppress the lateral movement of the etching solution. Therefore, the device wafer 2 whose crystal surface is (110)
In order to perform anisotropic etching at 0, the crystal plane of the side surface formed by the permeation of the etching solution is perpendicular to the (110) plane which is the crystal plane of the surface of the device wafer (111). It is necessary to investigate the plane orientation of the crystal plane that becomes the plane.

As a method for investigating the plane orientation of the crystal plane (111), the (111) plane is determined based on a major flat (orientation mark) attached to the device wafer 20 in order to confirm the crystal orientation of the device wafer 20. There is a way to find out. Alternatively, for example, some rectangular patterns with an angle of 0.1 ° are formed on the passivation film 22 of the device wafer 20 having a crystal plane of (110) for examining the plane orientation in advance. The pattern may be etched, and the surface that minimizes the rate of lateral etching may be employed (not shown).

As described above, the acceleration sensor is formed on the passivation film 22 of the device wafer 20 so that the crystal face of the side surface formed by anisotropic etching becomes the (111) plane perpendicular to the (110) plane. After forming the pattern of the structure and the fixed electrode constituting the structure, an anisotropic etching solution (eg, KOH, TMAH, hydrazine, C
anisotropic etching is performed from the pattern surface of the passivation film 22 to the boundary between the device wafer 20 and the oxide film 18 using sOH or the like. Through this process, the vibrating body, which is a basic component of the acceleration sensor, and the fixed electrode 6
And a fixed electrode 7 are formed from the same device wafer 20 (FIG. 3C). The depth of anisotropic etching depends on the gap between the electrodes of the acceleration sensor to be manufactured and the etching rate selection ratio ((11
(Ratio of etching rate of (0) plane to etching rate of (111) plane of silicon), structure of acceleration sensor,
An appropriate value is selected depending on the required performance. In an acceleration sensor that detects acceleration from a change in electrostatic capacitance, it is important to increase the interelectrode capacitance by reducing the interelectrode gap to improve the sensitivity. The gap between the formed electrodes depends on the patterning accuracy, the etching rate selection ratio, and the etching depth. Therefore, when the patterning accuracy and the etching rate selection ratio are constant, the minimum value of the gap between the electrodes to be formed can be determined by the etching depth.
Therefore, even if anisotropic etching is performed on a wafer having the same thickness, anisotropic etching is performed from one direction and anisotropic etching is performed from both sides. Can be suppressed. Therefore,
In the step of FIG. 3A, after forming the etching groove 21 on the oxide film 18, using the nitride film having the pattern of the structure on the surface having the etching groove 21 as a mask, an anisotropic thickness of about half the wafer thickness is obtained. It may be pre-etched by using a reactive etching (not shown).

Next, in the structure formed by etching from the device wafer 20, the passivation film 22 on the surface of the structure is removed by etching, and p-type or n-type impurities are diffused to the surface and side surfaces of the structure to form the p-type. Alternatively, the n-type impurity diffusion layer 24 is formed. By forming the impurity diffusion layer 24 on the surface and the side surface of the structure, the conductivity of the fixed electrode 6, the fixed electrode 7 and the vibrating body can be increased. However, the step of forming the impurity diffusion layer 24 may be omitted when the conductivity of the single crystal silicon that is the material of the device wafer 20 is high. After that, the oxide film 18 supporting the beam 3 and the mass body 4 of the vibrating body is removed by etching to release the beam 3 and the mass body 4 (FIG. 3).
(D)). Then, the metal electrode 8 is selectively metallized on the vibrating body of the structure formed from the device wafer 20, the fixed electrode 6 and the fixed electrode 7 by a sputtering device or the like (FIG. 3E).

Next, a separately prepared acceleration sensor element prepared by the above-described process using a silicon IC substrate 26 in which a detection circuit IC25 in which a detection circuit for detecting acceleration is integrated is incorporated by using a die bonding agent. Join on top of 14. Alternatively, it may be bonded to the acceleration sensor element 14 using a low temperature fusion bonding technique of silicon. Here, the low temperature fusion bonding technology of silicon is used for the detection circuit IC.
This is to prevent 25 from causing thermal destruction (FIG. 3).
(G)). After that, the bonding wire 27 is used to wire the structure and the metal electrode 8 on the detection circuit IC 25. Then, the individual acceleration sensors are separated by dicing. This dicing process is performed by the detection circuit IC 25.
It may be performed before joining the silicon IC substrate 26 in which the above is incorporated and the acceleration sensor element 14.

Alternatively, as described above, instead of separately preparing the silicon IC substrate 26 in which the detection circuit IC25 in which the detection circuit for detecting the acceleration is integrated is incorporated, the detection circuit IC25 is previously incorporated in the device wafer 20. You can leave it. As an assembling method, see Fig. 3.
After the step (b) is completed, the detection circuit IC 25 may be formed on the device wafer 20 on a mirror-finished surface. Or
The detection circuit I which has been integrated into the device wafer 20 from the beginning
It is also possible to incorporate C25. As described above, FIG.
Step (b), that is, after polishing the surface of the device wafer 20 and adjusting the thickness of the device wafer 20 to a desired thickness, the detection circuit IC 25 is mounted on the mirror-finished surface of the device wafer 20, and passivation is performed. The film 22 is deposited, the pattern of the acceleration sensor is formed, and the vibrating body, the fixed electrode 6, the fixed electrode 7, and the silicon IC substrate 26 are formed by anisotropic etching. After that, the passivation film 22 is removed, and the oxide film 18 exposed to the outside air by anisotropic etching is removed by etching to release the beam 3 and the mass body 4. After that, the metal electrode 8
Is formed, and the metal electrode 8 on the structure and the detection circuit IC 25 is wired using the bonding wire 27 (FIG. 3F). When such a method is used, the detection circuit IC2
The step of joining the silicon IC substrate 26 incorporating 5 to the substrate 9 can be omitted.

The acceleration sensor can also be manufactured by using the following method. This will be described with reference to FIG. Instead of depositing the oxide film 18 on the device wafer 20 and patterning and forming the etching groove 21 on the oxide film 18 by etching, the device wafer 2
Device wafer 20 by etching 0 itself
An etching groove 21 is formed in the device wafer 20 after the oxide film 18 is formed by thermal oxidation or a sputtering CVD method.
Is deposited on top (FIG. 4 (a)). After that, it is bonded to the substrate 9 by using fusion bonding of silicon (FIG. 4B). After that, the acceleration sensor can be manufactured by taking steps after the step of FIG. As in this method, an etching groove 21 having an appropriate depth is formed in the device wafer 20 itself by an etching technique, and the depth is adjusted (for example, several hundreds of μm), so that FIG.
The step (b), that is, the step of polishing the surface of the device wafer 20 and adjusting the thickness thereof can be omitted.

Although the material of the substrate 9 is silicon, glass (for example, a material having a linear expansion coefficient close to that of silicon such as aluminosilicate or borosilicate glass) is used.
You may use it for the material. An example of a process of manufacturing an acceleration sensor using the substrate 9 made of glass will be described with reference to FIG. In FIG. 5, 28 is a passivation film made of an oxide film or a nitride film.

A passivation film 28 is deposited on the device wafer 20 in which the detection circuit IC 25 is incorporated, and an etching groove 21 is formed by etching (FIG. 5A). Next, after removing the passivation film 28, the device wafer 20 and the substrate 9 are bonded by anodic bonding (FIG. 5B). Alternatively, the substrate 9 and the device wafer 20 may not be directly anodically bonded, but the substrate 9 and the device wafer 20 may be anodically bonded via an insulating film such as an oxide film or a nitride film. After that, the structure and the silicon IC substrate 26 are formed from the device wafer 20 by anisotropic etching (FIG. 5C). The passivation film 22 is removed, and the metal electrode 8 is selectively metallized on the structure (FIG. 5D). Alternatively, in order to perform anisotropic etching, the pattern of the metal electrode 8 is formed on the passivation film 22 before forming the pattern of the structure and the silicon IC substrate 26, and lift-off is performed to form Cr, A
You may form the metal electrode 8 which consists of u.

Next, a plan view and a side view (FIGS. 6 and 7) showing a state in which the acceleration sensor manufactured by any of the above-mentioned methods is housed in a package are shown. 6 and 7, 29 is a lead pin, 30 is a stem, 31 is a cap, and 32 is an adhesive. What is shown is a detection circuit I
A package of an acceleration sensor in which a silicon IC substrate 26 incorporating C25 is bonded onto the acceleration sensor element 14 (FIG. 6) and an acceleration sensor manufactured by incorporating the detection circuit IC25 in the device wafer 20 (FIG. 7). ). When the detection circuit is not integrated into an IC, the components of the acceleration sensor excluding the detection circuit IC25 on the ceramic substrate for the hybrid IC,
A detection circuit composed of discrete electronic components forming the detection circuit may be mounted and packaged (not shown). When adjusting the frequency characteristics of the sensor, a pressure medium (for example, air at a specific pressure, an inert gas such as nitrogen or Ar) or a liquid (for example, silicon oil) is enclosed in the cap 31 as needed. do it.

Since the step of packaging the acceleration sensor may adversely affect the acceleration sensor due to fine dust and dust entering between the electrodes of the acceleration sensor, it is necessary to perform this step in a clean environment. There is. It is also necessary to protect the acceleration sensor from contamination by chips generated in the dicing process.

Further, the structure shown in FIG. 8 may be adopted. In FIG. 8, 33 is an auxiliary support part, 34 is a protective substrate, and 35 is an etching groove. In addition, holes are formed in the protective substrate 34 in the portions facing the etching grooves 35 and the metal electrodes 8. As shown in FIG. 8, the auxiliary support portion 33
Is formed so as to surround the side surface of the acceleration sensor element 14 (including the detection circuit IC25 when it is formed on the same substrate), and the protective substrate 34 made of glass or the like is anodically bonded to the auxiliary support portion 33. The acceleration sensor is protected from contamination. At the time of anodic bonding, the auxiliary support portion 33 is used as an anode and the protective substrate 34 is used as a cathode to perform anodic bonding. Alternatively, when the material of the substrate 9 is glass, the substrate 9 may be used as an anode and the protective substrate 34 may be used as a cathode to perform anodic bonding. Alternatively, the substrate 9 and the auxiliary support portion 33 may be used as an anode, and the protective substrate 34 may be used as a cathode for anodic bonding. For the protective substrate 34, silicon having an insulating film such as an oxide film or a nitride film may be used. When the protective substrate 34 made of silicon having an insulating film is used, the low temperature fusion bonding of silicon may be used for the bonding with the auxiliary supporting portion 33. At the time of anodic bonding, an inert gas may be introduced or the internal pressure may be adjusted in order to optimize the frequency characteristics of the acceleration sensor. Further, by providing an electrode for electrically grounding the auxiliary support portion 33 and grounding it, the stray capacitance can be stabilized and can be used as an electrostatic shield (not shown).

The structure of the acceleration sensor having the auxiliary support portion 33 and the protective substrate 34 thus formed is the detection circuit IC2.
5 or a detection circuit composed of discrete components, mounted on a substrate composed of ceramics or the like, and can be housed in a simple plastic package (not shown). As a result, the cost of the acceleration sensor package can be reduced, and a lower cost acceleration sensor can be provided.

As shown in FIG. 8, an etching groove 35 is previously formed by wet etching or the like in a portion of the protective substrate 34 located in the vicinity of the upper portion of the mass body 4 in the vertical direction. It has the function of a stopper that prevents various displacements. The etching groove 35 includes the mass 4 and the beam 3.
The device wafer 20 may be provided with the etching groove 35 because it is intended to freely vibrate and.

Example 2. In the acceleration sensor of FIG.
Reference numeral 36 denotes a damping adjusting mechanism for adjusting the frequency characteristic of the acceleration sensor. When the mass body 4 is displaced by the inertial force, the side surfaces of all the mass bodies 4 which are perpendicular to the displacement direction are subjected to a resistance force by the surrounding medium (a pressure medium or a liquid enclosed for adjusting frequency characteristics). This resistance becomes larger as the area of the side surface of the mass body 4 perpendicular to the vibration direction becomes larger. In the acceleration sensor of FIG. 1, since the fixed electrode 6 and the fixed electrode 7 are arranged so as to face the mass body 4, it can be said that these configurations themselves have a damping adjusting function. However, the desired resistance force may not be obtained only by the area of the side surface perpendicular to the vibration direction of the mass body 4 in the acceleration sensor configured in FIG.

In the acceleration sensor of FIG. 9, in order to increase the area of the side surface perpendicular to the vibration direction of the mass body 4, two opposite sides of the mass body 4 are formed in a comb shape, and the comb shape facing the comb shape is formed. The damping adjusting mechanism 36 is provided. As a result, a new (111) crystal face forming an angle of 35.26 degrees with respect to the crystal face (110) face of the surface of the structure is generated. This is formed by anisotropically etching a portion where the angle formed by two (111) planes perpendicular to the (110) plane, which is the crystal plane of the structure, is 70.53 degrees. . In Example 1, it is designed so that the (111) plane forming an angle of 35.26 degrees with the (110) plane does not occur. When the (111) plane forming an angle of 35.26 degrees with the (110) plane is formed by performing anisotropic etching, it must be designed so that this plane does not hinder the movement of the mass body 4.

The resistance force received when the mass body 4 of the acceleration sensor is displaced by the inertial force is proportional to the area of the side surface perpendicular to the vibration direction of the mass body 4. Therefore, by adjusting the number of combs and the length of the comb-shaped damping adjusting mechanism 36 and the mass body 4, it is possible to adjust the resistance force received by the mass body 4, and as shown in FIG. It is possible to arbitrarily adjust the frequency characteristic (for example, critical damping state: ζ = 0.707, ζ: damping coefficient). Further, this frequency characteristic can be adjusted by changing the gas pressure in the package or enclosing a viscous liquid.

By designing the gap of at least one pair of the comb-shaped damping adjustment mechanism 36 and the mass body 4 to have a certain constant value,
It is also possible to provide a function of a stopper that prevents the beam 3 from being broken due to the large displacement of the mass body 4 due to excessive impact acceleration, or the attraction by the electrostatic attraction between the mass body 4 and the fixed electrode. By providing the damping adjusting mechanism 36 and the mass body 4 having the comb structure as described above, the frequency characteristic,
It is possible to provide an acceleration sensor having excellent impact resistance and reliability.

Example 3. FIG. 11 shows an example of the acceleration sensor of the third embodiment. In FIG. 11, 38 and 39 are comb-shaped fixed electrodes, and 40 is an actuating electrode. The combs of the mass body 4 are arranged asymmetrically so that the gap between the combs of the mass body 4 and the combs of the adjacent fixed electrodes 39 becomes smaller than the other. This is because when the mass body 4 is displaced by the inertial force, a capacitor formed in a portion where the gap between the comb of the mass body 4 and the adjacent fixed electrode 39 is small is a capacitor of the fixed electrode 39 adjacent to the comb of the mass body 4. This is because the gap value is designed so that the capacitance can be changed sufficiently larger than that of the capacitor formed in the portion having a large gap with the comb. As a result, the comb-shaped electrode pair 37 is formed at a portion where the gap between the comb of the mass body 4 and the comb of the adjacent fixed electrodes 39 is smaller than the other, and one comb-shaped electrode pair forms a capacitor. Is forming. Further, the comb of the mass body 4 and the comb of the adjacent fixed electrode 38 have the same relationship. Further, the gap of the comb-shaped electrode pair 37 formed by the mass body 4 and the fixed electrode 38 is made equal to the gap between the electrodes of the mass body 4 and the fixed electrode 6, and the comb-shaped electrode pair formed by the mass body 4 and the fixed electrode 39. The gap of 37 is made equal to the gap between the mass body 4 and the fixed electrode 7. Furthermore, the fixed electrode 6 and the fixed electrode 38 are electrically connected to the outside, and the fixed electrode 7 and the fixed electrode 39 are electrically connected to the outside. Alternatively, the fixed electrode 6 and the fixed electrode 38 may be made common and the fixed electrode 7 and the fixed electrode 39 may be made common from the beginning.

When the acceleration is detected from the change of the capacitance of the capacitor, the acceleration can be detected with higher sensitivity as the capacitance of the capacitor formed by the mass body 4 and the fixed electrode is larger. The capacitance of the capacitor is proportional to the electrode area. Therefore, the fixed electrode 38 and the fixed electrode 3
9 and the mass body 4 are comb-shaped, and the gap of the comb-shaped electrode pair 37 formed by the mass body 4 and the fixed electrode 38 is set to be equal to the gap between the mass body 4 and the fixed electrode 6, and 4 and the fixed electrode 39 are formed into a comb-shaped electrode pair 3
By setting the gap of 7 to be equal to the gap between the mass body 4 and the fixed electrode 7 and increasing the number of the comb-shaped electrode pairs 37, the capacitance of the capacitor can be reduced within a limited area (even if the element size is the same). It is possible to increase the capacitance. By forming the fixed electrode 38 and the fixed electrode 39 with comb-shaped electrodes, the fixed electrode 38 and the fixed electrode 39 are formed.
Will have both a damping control function and a function of increasing the capacitance of the capacitor. Therefore, in designing the number of pairs of the comb-shaped electrode pairs 37, it is necessary to consider both of them.

In FIG. 11, the mass body 4 is provided with a cavity,
An actuate electrode 40 is provided therein. This allows the acceleration sensor to have a self-diagnosis function. That is, when a potential difference is generated between the actuating electrode 40 and the mass body 4, the mass body is displaced by electrostatic attraction. This electrostatic attraction is apparently equal when an external force is applied to the acceleration sensor, and it is possible to diagnose whether or not the mass body 4 of the acceleration sensor is reliably displaced by this, from the value output according to the capacitance change of the capacitor. .
In this sense, the acceleration sensor includes an actuate electrode 40.
It becomes possible to have a self-diagnosis function by providing. Alternatively, an electrode for actuate can be obtained by electrically disconnecting a part of the fixed electrode 38. The actuating electrode 40 can also be applied to FIGS. 1, 8, and 9 and FIGS. 12, 13, and 16 described later. Further, a pair of the fixed electrode 6 and the fixed electrode 38, or the fixed electrode 7 and the fixed electrode 39 is disposed slightly closer to the mass body 4 with respect to the other pair, and serves as a stopper for limiting the displacement of the mass body 4. It is also possible to do so.

Example 4. FIG. 12 shows an example of the acceleration sensor of the fourth embodiment. In FIG. 12, reference numeral 41 denotes a mass body protruding portion. As shown in FIG. 12, the beam 3 is not protruded from the mass body 4 but is formed along one side of the mass body 4, whereby the acceleration sensor can be manufactured in a smaller size. Further, by providing the mass body protruding portion 41 on the vibrating body, the distance between the beam 3 and the anchor 5 and the mass body protruding portion 41 is designed to be a value smaller than the distance between the beam 3 and the fixed electrode. It can be a stopper.

FIG. 13 is a modification of FIG. In FIG. 13, reference numeral 42 denotes a mass body mass adjusting hole for adjusting the mass of the mass body 4. FIG. 13 shows a comb-shaped fixed electrode 6 and fixed electrode 7, and a damping adjusting mechanism 3.
6, an electrode 40 for actuate, and a mass body mass adjusting hole 42. The mass of the mass body 4 can be adjusted by the size of the mass body mass adjusting hole 42. As a result, the frequency characteristic of the acceleration sensor and the sensitivity can be adjusted by changing the size of the mass body mass adjusting hole 42 without changing the length of the beam 3.

Example 5. In FIG. 14, the beam 3 and the anchor 5 are formed inside the mass body 4. If the structure has two anchors as in the previous embodiments, the substrate 9
When the material of the structure is different from that of the structure, there is a problem that stress is generated in the beam 3 due to the strain generated in the substrate 9 and the two anchors 4 of the vibrating body due to the difference in linear expansion coefficient. When the vibrating body has such a structure, even if the linear expansion coefficient is different from that of the substrate 9, the beam 3 is not stressed by the strain generated in the substrate 9 and the anchor.

Example 6. In FIG. 15, two acceleration sensors whose displaceable directions are orthogonal to each other are manufactured on the same substrate. In FIG. 15, 43 is an x-axis direction acceleration sensor for detecting the x-axis direction acceleration, and 44 is a y-axis direction acceleration sensor for detecting the y-axis direction acceleration. This makes it possible to measure acceleration along two axes of x-axis and y-axis.

Example 7. Example 7 is an angular velocity sensor capable of detecting the angular velocity of an object that makes a rotational motion. FIG. 16 is a plan view (a) showing the configuration of an angular velocity sensor for detecting the angular velocity of an object that makes a rotational motion, and a cross-sectional view (b) taken along line FF thereof. In FIG. 16, 45 is a drive electrode, 46 and 47 are vibration monitoring electrodes, and 48 and 49 are lower fixed electrodes. The vibrating body of this angular velocity sensor includes four beams 3, two mass bodies 4, and three anchors 5. Further, the structure of this angular velocity sensor includes a vibrating body, a driving electrode 45, and a vibration monitoring fixed electrode 4.
6 and a vibration monitoring electrode 47. The specific structure of this sensor is such that a drive electrode 45, which is a fixed electrode, is provided between two mass bodies 4 of a vibrator that are electrically equal in potential.
The vibration monitor fixed electrode 46 and the vibration monitor fixed electrode 47 are arranged outside each mass body 4. This angular velocity sensor includes a vibrating body and a drive electrode 45.
And a fixed electrode for vibration monitor 46 and a fixed electrode for vibration monitor 47 are formed from the same wafer by anisotropic etching. Further, a lower fixed electrode 48 and a lower fixed electrode 49 for detecting the vibration of the mass body 4 are provided on the substrate 9 located on the lower surface of each mass body 4. Further, similarly to the acceleration sensor, an electrode for electrically grounding is provided on the auxiliary support portion 33 and grounded,
Stray capacitance can be stabilized and can also be used as an electrostatic shield (not shown).

Next, the operation of this angular velocity sensor will be described with reference to FIG. In FIG. 17, 50 and 51 are capacitors composed of the mass body 4 and the lower fixed electrodes 48 and 49, 52 is a DC bias voltage source, and 53 is AGC.
(Auto gain control) circuit, 54 is a CV (capacitance-voltage) converter, and 58 is an AC voltage source. AC voltage source 58 connected to drive electrode 45 and D for bias
With the C bias voltage source 52, the two mass bodies 4 are excited and oscillated according to the frequency of the AC voltage source 58 with a phase difference of 180 degrees from each other due to the electrostatic attraction generated between the two mass bodies 4. At this time, when there is an angular velocity vector Ωx in the horizontal axis direction shown in the plan view of the drawing, that is, the angular velocity sensor is
When there is an angular velocity Ωx generated by the rotational movement about the horizontal axis, Coriolis force as an inertial force is generated in the mass body 4 in the direction shown in the FF sectional view of FIG.
Therefore, when rotating, the mass body 4 of this sensor
Causes the vibration excited by the AC voltage source 58 and the vibration caused by the Coriolis force generated by the rotational movement to be superimposed.
Further, the direction of excitation vibration due to the electrostatic attractive force generated by the AC voltage source 58 and the direction of vibration due to the Coriolis force generated due to the rotational movement are orthogonal to each other.

Displacement u in the y direction due to the excited vibration of the mass body 4
It is assumed that the speeds uy ′ in the y and y directions have the following relationship. uy = A × sin (ωrT) ・ ・ ・ ・ ・ ・ ・ ・ (3) uy ′ = A × ωr × cos (ωrT) ・ ・ ・ ・ ・ ・ ・ ・ (4) A: y of the mass body 4 Maximum displacement in direction ωr: Angular frequency of y-direction vibration of the mass body 4 When rotating, the mass body 4 produces a Coriolis force Fc proportional to uy ′, the direction of which is as shown in FIG. Coriolis force Fc is the angular velocity of the measurement target, Ωx,
When the mass of each mass body 4 is m, there is a relationship of Fc = 2Ωx × m × uy ′ ... (5). Further, the relationship between the Coriolis force Fc and the displacement uz in the z direction is Fc = kz × uz (6) when the rigidity in the z direction is kz. From these two equations (6) and (7), uz = (2Ωx × m × uy ′) / kz (7) From this, it can be seen that the electrostatic capacitance between the mass body 4 and the lower fixed electrode 48 and the electrostatic capacitance between the mass body 4 and the lower fixed electrode 49 change in a form modulated by the excitation vibration. . This state is shown in FIG. 17A, and this equivalent circuit is shown in FIG. 17B. An example of a detection circuit configuration for detecting the angular velocity is shown in FIG. 17 (c).

Excited vibration displacement u of the two mass bodies 4 in the y direction
Since y is 180 degrees out of phase with each other, the phases of the Coriolis forces Fc acting on the two mass bodies are also out of phase with each other by 180 degrees. Therefore, the capacitance of the capacitor formed by the mass body 4 and the lower fixed electrode 48, and the mass body 4 and the lower fixed electrode 49.
The capacitance of the capacitor formed by and increases when one increases. The voltage proportional to the change in the differential capacitance is shown in FIG.
It is taken out by the circuit shown in (c). This detection circuit is shown in FIG.
The basic configuration is the same as that of (c). The different point is that it has a DC bias voltage source 52, an AC voltage source 58, an AGC (auto gain control) circuit 53, a vibration monitor electrode 46, and a vibration monitor electrode 47 in order to excite and vibrate the mass body at a constant amplitude. is there. Further, the CV (capacitance-voltage) converter 54 includes 12, 13, 1 in FIG.
It is represented by the circuit formed by 5, 16, and 17.

Next, an example of a manufacturing process of the angular velocity sensor for detecting the angular velocity of the object which makes the rotational motion will be described with reference to FIG. FIG. 18 is a diagram showing the manufacturing process of the angular velocity sensor when the material of the substrate 9 is glass (for example, a material having a coefficient of linear expansion close to that of silicon such as aluminosilicate or borosilicate glass). The manufacturing process of this sensor is
There are many points in common with the manufacturing process of the acceleration sensor that detects the acceleration of a linearly moving object. Here, the beam 3 needs to have the same width and thickness. Because the driving frequency of vibration in the y-axis direction uses the structural resonance point in the vibration direction or its vicinity in order to increase the detection sensitivity, the structural resonance point in the z-axis direction modulated by this frequency is used. This is because it is desirable to keep it in common.

First, the etching groove 21 is formed on the device wafer 20 by photolithography and etching, and then the oxide film 1 is formed on the surface where the etching groove 21 is formed.
8 is formed. In this case, the sensitivity of angular velocity detection depends on the capacitance of the capacitor formed by the mass body 4 and the lower fixed electrodes 48 and 49. The etching groove 21 defines the amount by which the mass body 4 can be displaced. That is, the detection sensitivity is the etching groove 2
Since it depends on the depth of 1, it is about several μm (for example, 2 μm to 3 μm). On the other hand, the lower fixed electrode 48 is formed on the substrate 9.
Then, the lower fixed electrode 49 is selectively metallized by vapor deposition or sputtering (FIG. 18A). Alternatively, the metal electrode 8 may be formed by lift-off. After this,
The device wafer 20 and the substrate 9 are aligned and anodically bonded. Next, the thickness of the device wafer 20 is adjusted. The drive frequency of vibration in the y-axis direction is the same as the structural resonance point in the z-axis direction that is modulated by this frequency because the structural resonance point in the vibration direction or its vicinity is used in order to increase the detection sensitivity. It is desirable to leave it. Therefore, the thickness of the device wafer 20 may be adjusted to be the same as the width of the beam 3 formed from the device wafer 20 (FIG. 18B). Alternatively, it is possible to adjust the frequency characteristics and the sensitivity of the angular velocity sensor by providing the mass body 4 with a mass body mass adjusting hole 42 (not shown) for adjusting the mass of the mass body 4.

When the substrate 9 is made of silicon, it is necessary to insulate the substrate 9 from the lower fixed electrode 48 and the lower fixed electrode 49. Therefore, an insulating film made of an oxide film or a nitride film is formed on the surface of the substrate 9. And the patterns of the lower fixed electrode 48 and the lower fixed electrode 49 are formed, and then the lower fixed electrode 48 and the lower fixed electrode 49 are selectively metallized by vapor deposition or sputtering. Alternatively, the lower fixed electrode 4
It is also possible to form the lower fixed electrode 48 and the lower fixed electrode 49 by lift-off by performing vapor deposition or sputtering after forming the resist patterns of the lower fixed electrode 8 and the lower fixed electrode 49.
Alternatively, the impurity diffusion layers formed by diffusing p-type or n-type impurities in the substrate 9 itself using the insulating film made of an oxide film or a nitride film as a mask may be used as the lower fixed electrodes 48 and 49 (not shown). No). After that, the device wafer 20 and the substrate 9 are aligned, and both are bonded by low-temperature fusion bonding.

Next, the PEC is formed on the surface of the device wafer 20.
After the passivation film 22 made of a nitride film or an oxide film is deposited by VD or sputtering, patterning is performed (FIG. 18C). At this time, when anisotropic etching is used when etching the device wafer 20 in the next step, the crystal orientation of the device wafer 20 must be taken into consideration. How to find the crystal orientation,
Since the anisotropic etching has already been described,
Here, it is omitted.

Next, the device wafer 20 is anisotropically etched by wet etching using an anisotropic etching solution or dry etching (for example, reactive ion etching (RIE) method).
A structure having the drive electrode 45, the vibration monitor fixed electrode 46, and the vibration monitor fixed electrode 47, and the auxiliary support portion 54 are formed, the passivation film 22 is removed, and the metal electrode 8 is selected by vapor deposition or sputtering. Metallize (FIG. 18 (d)). Alternatively, the structure and silicon I may be formed on the passivation film 22 for anisotropic etching.
The pattern of the metal electrode 8 may be formed before forming the pattern of the C substrate 26, and the metal electrode 8 made of Cr, Au or the like may be formed by lift-off.

Next, in a depressurized atmosphere (for example, a vacuum or a state close to a vacuum), a protective substrate 34 (a glass material in this example) having a hole provided in a portion facing the etching groove 35 and the metal electrode 8 and a device wafer 20 and 20 are anodically bonded. At the time of anodic bonding, the auxiliary support portion 33 is used as an anode and the protective substrate 34 is used as a cathode to perform anodic bonding. Or substrate 9
When the material is glass, the substrate 9 may be used as an anode and the protective substrate 34 may be used as a cathode for anodic bonding. Alternatively, the substrate 9 and the auxiliary support portion 33 may be used as an anode, and the protective substrate 34 may be used as a cathode for anodic bonding. Protective substrate 3
When 4 is silicon, low temperature fusion bonding is performed. In an angular velocity sensor that detects the angular velocity of a rotating object,
Since the resonance phenomenon of the mass body is used, it is necessary to suppress damping (for example, damping due to air viscosity or squeeze damping) that occurs between the mass body and other electrodes as much as possible. Therefore, the etching groove 35 of the protective substrate 34
The cavity around the mass body 4 formed by the etching groove 21 of the device wafer 20 is preferably in a vacuum or in a state close to a vacuum (FIG. 18E).

Through the above steps, the structure of the angular velocity sensor for detecting the angular velocity of the rotating object is completed. This process has many common parts with the manufacturing process of the acceleration sensor that detects the acceleration of the object that moves linearly, so that the manufacturing process of the acceleration sensor that detects the acceleration of the object that moves linearly It is possible to manufacture an angular velocity sensor that detects the angular velocity. Further, the detection circuit IC 25 for detecting the angular velocity can be built in the substrate 9.

Further, in the two angular velocity sensors for detecting the angular velocity of the rotating object, by arranging them on the same substrate so that the vibration excitation directions of the AC voltage source 58 are orthogonal to each other, the two axes having different rotation directions are provided. In contrast, an angular velocity sensor capable of detecting an angular velocity is formed (not shown).

The angular velocity sensor according to the seventh embodiment and the first embodiment.
By forming at least one of the angular velocity sensors described in 5 to 5 on the same substrate, an angular velocity sensor capable of detecting the angular velocity due to the rotational movement and the acceleration due to the linear movement can be provided. (Not shown)

[0111]

The inertial force sensor according to the first aspect of the present invention is formed by joining a substrate and a wafer having a (110) plane to form a two-layer structure, and anisotropically etching the wafer. Since the structure having the vibrating body and the fixed electrode is formed, it is possible to reduce the residual strain generated when the inertial force sensor is manufactured.

In the inertial force sensor according to the second aspect of the present invention, the beam and the mass body are formed so that the shape of the mass body is rotationally symmetrical by 180 degrees in the plane of the wafer. Therefore, the amount by which the mass body can be displaced can be increased, so that the change in the capacitance of the capacitor formed by the mass body and the fixed electrode can be increased.

In the inertial force sensor according to the third aspect of the present invention, since the shape of the mass body is a parallelogram, the side surface of the mass body is formed of the (111) plane perpendicular to the (110) plane. Guarantee.

In the inertial force sensor according to the fourth aspect of the present invention, the mass body has a parallelogram shape, and one end of the beam is provided on the acute angle side of the parallelogram mass body. It is guaranteed that the side surface near the boundary between the mass body and the beam formed by etching the wafer is formed only by the (111) plane perpendicular to the crystal plane (110) plane.

In the inertial force sensor according to the fifth aspect of the present invention, the structure is such that the dimension of the beam with respect to the vibration direction of the mass body is smaller than the dimension of the beam in other directions, so that the sensitivity in the specific direction is increased. Is improved.

The inertial force sensor according to the sixth or seventh aspect is to improve the frequency characteristic of the inertial force sensor by providing a damping adjusting mechanism for adjusting the vibration characteristic of the mass body. Is possible.

In the inertial force sensor according to the eighth aspect, the frequency characteristic of the inertial force sensor can be improved and the capacitance of the capacitor in the inertial force sensor can be increased by providing the comb-shaped fixed electrode. Is possible.

The inertial force sensor according to the ninth or tenth aspect is provided with a stopper for limiting the displacement of the mass body, so that an excessive displacement of the mass body exerts an excessive force on the beam of the vibrating body. It is possible to protect the vibrating body from damage due to stress. Further, it becomes possible to prevent adsorption between the mass body and the fixed electrode.

The inertial force sensor according to claim 11 is:
By hollowing out the vicinity of the center of the mass body, it is possible to adjust the mass of the mass body according to the size of the hollowed body, and thus it is possible to adjust the frequency characteristic of the inertial force sensor.

The inertial force sensor according to claim 12 is:
By providing the beam and the anchor in the hollow portion of the mass body having a hollowed-out shape near the center, the inertial force sensor becomes smaller. Further, it is possible to avoid the stress generated when the materials of the wafer and the substrate are different.

The inertial force sensor according to claim 13 is
The inertial force sensor can be provided with a self-diagnosis function by providing an actuating electrode around the hollow part of the mass body having a hollowed-out shape near the center or around the vibrating body.

The inertial force sensor according to claim 14 is
The inertial force sensor can be downsized by providing an IC detection circuit for detecting acceleration on the wafer for forming the structure.

The inertial force sensor according to claim 15 is:
By providing an IC detection circuit for detecting acceleration on the structure, the inertial force sensor can be downsized.

The inertial force sensor according to claim 16 is:
By providing the auxiliary support portion around the structure and the protective substrate for sealing the structure on the auxiliary support portion, the cost of the package can be reduced.

The inertial force sensor according to claim 17 is:
By incorporating at least two inertial force sensors having different detection directions on the same substrate, an inertial force sensor capable of detecting the acceleration of a moving object by dividing it into at least two components is realized.

The inertial force sensor according to claim 18 is
A substrate provided with two lower fixed electrodes and a structure formed by etching a wafer made of single crystal silicon having a (110) plane and bonded to the substrate along the (111) plane direction. The structure includes two mass bodies positioned above the two lower fixed electrodes with a gap,
A vibrating body having a beam that supports the mass body and is positioned with a gap from the substrate, and an anchor that supports the beam and is bonded to the substrate; and a vibrator provided outside the mass body.
By providing one fixed electrode and the drive electrode located between the two mass bodies, it becomes possible to realize an inertial force sensor that detects an angular velocity from the Coriolis force generated by the rotational movement.

The inertial force sensor according to claim 19 is:
Since the shape of the beam and the mass body is configured to have a rotational symmetry of 180 degrees in the plane of the wafer, the displacement of the mass body is translated, so that the amount of displacement of the mass body can be increased. The change in the capacitance of the capacitor formed by the mass body and the fixed electrode can be increased.

The inertial force sensor according to claim 20 is:
The parallelogram shape of the mass body ensures that the side surface of the mass body is formed by the (111) plane perpendicular to the (110) plane.

The inertial force sensor according to claim 21 is
The mass has a parallelogram shape, and one end of the beam has a structure in which one end of the beam is located on the acute angle side of the parallelogram mass, so that the boundary between the mass and the beam formed by etching the wafer. It is guaranteed that the side surface in the vicinity is formed only by the (111) plane perpendicular to the crystal plane (110) plane.

The inertial force sensor according to claim 22 is
By hollowing out the vicinity of the center of the mass body, it is possible to adjust the mass of the mass body according to the size of the hollowed body, and thus it is possible to adjust the frequency characteristic of the inertial force sensor.

The inertial force sensor according to claim 23 is
The inertial force sensor can be downsized by providing an IC detection circuit for detecting the angular velocity on the wafer for forming the structure.

The inertial force sensor according to claim 24 is
The inertial force sensor can be downsized by providing an IC detection circuit for detecting the angular velocity on the structure.

The inertial force sensor according to claim 25 is
By providing the auxiliary support portion around the structure and the protective substrate for sealing the structure on the auxiliary support portion, the cost of the package can be reduced.

The inertial force sensor according to claim 26 is
By incorporating at least two inertial force sensors having different detection directions on the same substrate, an inertial force sensor capable of detecting the angular velocity of a moving object by dividing it into at least two components is realized.

With the method for manufacturing an inertial force sensor according to any one of claims 27 to 28, high sensitivity,
It is possible to provide a highly reliable inertial force sensor.

[Brief description of drawings]

FIG. 1 is a plan view and a sectional view of an acceleration sensor according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a detection principle of the acceleration sensor according to the first embodiment of the present invention, a diagram showing an equivalent circuit thereof, and a diagram showing an example of a detection circuit for detecting acceleration.

FIG. 3 is a diagram showing an example of a manufacturing process of the acceleration sensor according to the first embodiment of the present invention.

FIG. 4 is a diagram showing an example of a manufacturing process of the acceleration sensor according to the first embodiment of the present invention.

FIG. 5 is a diagram showing an example of a manufacturing process of the acceleration sensor according to the first embodiment of the present invention.

FIG. 6 is a diagram showing an example of packaging of the acceleration sensor according to the first embodiment of the present invention.

FIG. 7 is a diagram showing an example of packaging of the acceleration sensor according to the first embodiment of the present invention.

FIG. 8 is a diagram showing a plan view (a) and a cross-sectional view (b) when the acceleration sensor of Example 1 of the present invention is packaged on a glass substrate.

9A and 9B are a plan view and a cross-sectional view of an acceleration sensor according to a second embodiment of the present invention.

FIG. 10 is a diagram showing changes in gain with respect to frequency when damping adjustment is performed and when the acceleration sensor of Example 2 of the present invention is not adjusted.

11A and 11B are a plan view and a sectional view of an acceleration sensor according to a third embodiment of the invention.

FIG. 12 is a diagram showing an example of an acceleration sensor according to a fourth embodiment of the invention.

FIG. 13 is a diagram showing an example of an acceleration sensor according to a fourth embodiment of the present invention.

14A and 14B are a plan view and a sectional view showing an example of an acceleration sensor according to a fifth embodiment of the invention.

FIG. 15 is a diagram showing an example of an acceleration sensor according to a sixth embodiment of the present invention.

16A and 16B are a plan view and a sectional view of an angular velocity sensor according to a seventh embodiment of the present invention.

FIG. 17 is a diagram showing a detection principle of an angular velocity sensor according to a seventh embodiment of the present invention, a diagram (b) showing an equivalent circuit thereof, and a diagram showing an example of a detection circuit for detecting an angular velocity.

FIG. 18 is a diagram showing an example of manufacturing process of the angular velocity sensor according to the seventh embodiment of the present invention.

FIG. 19 is a diagram showing a conventional acceleration sensor.

[Explanation of symbols]

3: Beam 4: Mass body 5:
Anchor 6: Fixed electrode 7: Fixed electrode 8:
Metal electrode 9: Substrate 10: Capacitor 1
1: Capacitor 12: AC signal source 13: Inverting amplifier 1
4: Acceleration sensor element 15: Charge amplifier 16: Demodulator 1
7: Filter 18: Oxide film 19: Oxide film 2
0: Device wafer 21: Etching groove 22: Passivation film 23: Passivation film 2
4: Impurity diffusion layer 25: Detection circuit IC 26: Silicon IC substrate 2
7: Bonding wire 28: Passivation film 2
9: Lead pin 30: Stem 31: Cap 3
2: Adhesive 33: Auxiliary support 34: Protective substrate 3
5: Etching groove 36: Damping adjusting mechanism 37
Comb-shaped electrode pair 38: fixed electrode 39: fixed electrode 4
0: Actuate electrode 41: Mass body protrusion 4
2: Mass body mass adjustment hole 43: x-axis direction acceleration sensor 4
4: y-axis direction acceleration sensor 45: drive electrode 46: vibration monitor electrode 4
7: Vibration monitoring electrode 48: Lower fixed electrode 49: Lower fixed electrode 5
0: Capacitor 51: Capacitor 52: DC bias voltage source 53: AGC (auto gain control) circuit 54: CV (capacitance-voltage) converter 5
5: Silicon substrate 56: Glass substrate 57: Glass substrate 5
8: AC voltage source

Claims (32)

[Claims] 1. A substrate, a substrate bonded to the substrate, and (11)
A wafer made of single crystal silicon having a (0) plane is
1) A structure made by etching along a plane direction, the structure having a mass positioned with respect to the substrate, a mass supporting the mass, and the substrate A vibrating body having a beam positioned with a gap, and an anchor that supports the beam and is bonded to the substrate, and a fixed electrode positioned on a side surface of the mass body. An inertial force sensor comprising a movable electrode and electrically detecting a displacement of the movable electrode. 2. The inertial force sensor according to claim 1, wherein the beam and the mass body are shaped to have rotational symmetry of 180 degrees in the wafer plane. 3. The inertial force sensor according to claim 1, wherein the mass body has a parallelogram shape. 4. The mass body has a parallelogram shape,
The inertial force sensor according to claim 3, wherein one end of the beam is located on an acute angle side of the parallelogram. 5. The dimension of the beam in the vibration direction of the mass body is smaller than the dimension of the beam in other directions,
The inertial force sensor according to claim 1, wherein the vibrating body has a beam that can selectively vibrate in only one direction. 6. The inertial force sensor according to claim 1, further comprising a damping adjusting mechanism for adjusting a vibration characteristic of the mass body. 7. The inertial force sensor according to claim 6, wherein at least one side of the mass body is comb-shaped, and a comb-shaped damping adjusting mechanism facing the comb-shaped portion is provided. 8. The inertial force sensor according to claim 1, wherein at least one side of the mass body is comb-shaped, and a comb-shaped fixed electrode facing the comb-shaped portion is provided. 9. The inertial force sensor according to claim 1, further comprising a stopper that limits displacement of the mass body. 10. The inertial force sensor according to claim 9, wherein at least one side of the mass body is comb-shaped, and a comb-shaped stopper facing the comb-shaped portion is provided. 11. The inertial force sensor according to claim 1, having a shape in which the vicinity of the center of the mass body is hollowed out. 12. The inertial force sensor according to claim 11, wherein the mass body has a hollowed-out shape near the center, and the beam and the anchor are provided in a hollow portion of the mass body. 13. The actuation electrode is provided in the hollow mass of the mass or around the vibrating body, wherein the mass has a hollowed-out shape in the vicinity of the center.
11. The inertial force sensor according to any one of 1 to 12. 14. The inertial force sensor according to claim 1, further comprising an IC detection circuit for detecting acceleration on the wafer for forming the structure. 15. The inertial force sensor according to claim 1, wherein the detection circuit is provided on the structure. 16. The inertial force according to claim 1, further comprising: an auxiliary support portion around the structure, and a protective substrate for sealing the structure on the auxiliary support portion. Sensor. 17. The inertial force sensor according to claim 1, wherein at least two inertial force sensors having different detection directions are incorporated on the same substrate. 18. A substrate provided with two lower fixed electrodes, and a wafer which is bonded to the substrate and is made of single crystal silicon having a (110) plane and is etched along the (111) plane direction. And two mass bodies that are located above the two lower fixed electrodes with a space, and that support the mass body and are located with a space between the substrate and the two mass bodies. A vibrating body having a beam for controlling the beam and an anchor that supports the beam and is bonded to the substrate, two fixed electrodes provided outside the mass body, and a drive electrode located between the two mass bodies. An inertial force sensor comprising: a mass electrode as a movable electrode, and a displacement of the movable electrode being electrically detected. 19. The inertial force sensor according to claim 18, wherein the beam and the mass body are shaped so as to have rotational symmetry of 180 degrees in the wafer plane. 20. The inertial force sensor according to claim 18, wherein the mass body has a parallelogram shape. 21. The inertial force sensor according to claim 20, wherein the mass body has a parallelogram shape, and one end of the beam is located on an acute angle side of the parallelogram. 22. The inertial force sensor according to claim 18, which has a shape in which the vicinity of the center of the mass body is hollowed out. 23. The inertial force sensor according to claim 18, further comprising an IC detection circuit for detecting an angular velocity on the wafer for forming the structure. 24. The inertial force sensor according to claim 18, wherein the detection circuit is provided on the structure. 25. The inertial force according to claim 18, further comprising: an auxiliary support portion around the structure, and a protective substrate for sealing the structure on the auxiliary support portion. Sensor. 26. The inertial force sensor according to claim 18, wherein at least two inertial force sensors having different detection directions are incorporated on the same substrate. 27. A method for manufacturing an inertial force sensor, comprising the following steps (1) to (5). (1) The substrate having the first insulating film deposited on the surface thereof and the wafer of single crystal silicon having the crystal surface of the surface having the second insulating film deposited on the (110) surface are formed of the first insulating film. After forming an etching groove on the surface of the film or on the surface of the second insulating film, bonding the surfaces having the insulating film to each other so as to face each other. (2) The back surface of the surface having the second insulating film of the wafer Polishing step (3) A third insulating film is deposited on the back surface of the surface of the wafer having the second insulating film, and etching is performed to obtain a desired pattern on the third insulating film. After removing the third insulating film, anisotropic etching is performed along the (111) plane direction of the wafer up to the boundary between the wafer and the second insulating film, whereby the vibrating body is formed. , The fixed electrode and the (4) A step of releasing the mass body and the beam by removing the second insulating film exposed by etching the wafer in the step (3) by etching (5) Step of selectively metallizing a metal electrode on the vibrating body and the fixed electrode 28. A method for manufacturing an inertial force sensor, comprising the following steps (1) to (4). (1) A substrate having a first insulating film deposited on the surface thereof, and a crystal plane of the surface having a (110) plane and at least one etching groove, and a second insulating film on the surface having the etching groove. Bonding a film-deposited wafer made of single crystal silicon so that the surfaces having the insulating film face each other (2) depositing a third insulating film on the back surface of the surface having the second insulating film of the wafer Then, after removing the unnecessary third insulating film by etching to obtain a desired pattern on the third insulating film, anisotropic etching is performed along the (111) plane direction of the wafer. Etching the wafer to the boundary between the wafer and the second insulating film to form the structure including the vibrating body and the fixed electrode. (3) The wafer was etched in the step (2). Exposed by Step of selecting metallized metal electrode on said mass body and said step of releasing the beam (4) the vibrator and the fixed electrode by removing by etching the second insulating film 29. A method for manufacturing an inertial force sensor, comprising the following steps (1) to (3). (1) The substrate and the crystal plane of the surface are (110) planes,
And a step of bonding a wafer made of single crystal silicon having at least one etching groove so that the etching groove and the substrate face each other (2) depositing an insulating film on the back surface of the bonding surface of the wafer,
After removing the unnecessary insulating film by using etching in order to obtain a desired pattern in the insulating film, anisotropic etching is performed along the (111) plane of the wafer to form the vibrator. And (3) a step of selectively metallizing a metal electrode on the fixed electrode and the vibrating body. 30. A method of manufacturing an inertial force sensor, comprising the following steps (1) to (5). (1) A substrate having a lower fixed electrode attached to the surface via a first insulating film, and a wafer made of single crystal silicon having a (110) crystal face on which a second insulating film is deposited. After forming an etching groove on the surface of the second insulating film, bonding the lower fixed electrode and the etching groove so as to face each other. (2) A back surface of the surface of the wafer having the second insulating film is formed. Step of polishing (3) A third insulating film is deposited on the back surface of the surface of the wafer having the second insulating film, and an unnecessary third film is formed on the surface by etching to obtain a desired pattern. After removing the insulating film, etching is performed to the boundary between the wafer and the second insulating film along the (111) plane direction of the wafer by using anisotropic etching, whereby the vibrating body and the fixed electrode are formed. And the drive electrode (4) The second insulating film exposed by etching the wafer in step (3) is removed by etching to remove the mass and the beam. And (5) a step of selectively metallizing a metal electrode on the vibrating body, the fixed electrode, and the drive electrode. 31. A method for manufacturing an inertial force sensor, comprising the following steps (1) to (5). (1) A substrate having a lower fixed electrode attached to the surface thereof via a first insulating film, and a crystal plane of the surface having a (110) plane and having at least one etching groove, and a surface having the etching groove. A step of joining a wafer made of single crystal silicon having a second insulating film deposited thereon so that the lower fixed electrode and the etching groove face each other (2) Step 3 of polishing the back surface. (3) Depositing a third insulating film on the back surface of the surface of the wafer having the second insulating film, and using etching to obtain a desired pattern on the surface. After removing the third insulating film, anisotropic etching is used to etch along the (111) plane direction of the wafer to the boundary between the wafer and the second insulating film. Fixed electrode, (4) A step of forming the structure having a drive electrode (4) The second insulating film exposed by etching the wafer in the step (3) is removed by etching to remove the mass. Step of releasing the body and the beam (5) Step of selectively metallizing a metal electrode on the vibrating body, the fixed electrode, and the drive electrode 32. A method for manufacturing an inertial force sensor, comprising the following steps (1) to (4). (1) A substrate having a lower fixed electrode attached to the surface thereof, and a single crystal silicon wafer having a crystal plane on the surface of which is a (110) plane and having at least one etching groove, the lower fixed electrode electrode and the etching Bonding so that the grooves face each other (2) Polishing the back surface of the bonding surface of the wafer (3) Depositing an insulating film on the back surface of the bonding surface of the wafer,
The vibrator is formed by removing the insulating film by etching to obtain a desired pattern on the surface and then etching the wafer along the (111) plane direction of the wafer by anisotropic etching. And a step of producing the structure including the fixed electrode and the drive electrode. (4) A step of selectively metallizing a metal electrode on the vibrating body, the fixed electrode, and the drive electrode.