JP2000097708A - Angular velocity sensor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an angular velocity sensor capable of driving in a large amplitude by suppressing an influence of air damping and particularly electrostatically driving by a pectinated structure in the atmosphere. SOLUTION: Primary vibrator bodies 17, 18 are coupled to a square frame 4 via primary beams 15, 16, respectively, and a secondary vibrator body 37 is coupled to the bodies 17, 18 via secondary beams 35, 36, respectively. An acceleration sensor element 67 is installed at the body 37. The body 37 is vibrated in the same direction (X-axis direction) as those of the bodies 17, 18 by vibration transmissions from the bodies 17, 18. The element 67 detects a Corioris force in the direction (Y-axis direction) perpendicular to the vibrating direction in the case of applying an angular velocity at the time of vibrating the body 37 according to a change of an electrostatic capacity of a pectinated structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration type angular velocity sensor.

[0002]

2. Description of the Related Art A vibration type angular velocity sensor is disclosed in
No. 1022. The principle of this angular velocity sensor will be described with reference to FIG. Comb electrodes (fixed electrodes for excitation) 300, 301, 302 and movable electrode 30 for excitation
3, 304, 305, 306
The mass portions 309, 310 of the beam structures 307, 308 are vibrated in a direction (Y direction) parallel to the surface of the substrate. At this time, if yaw Ω is generated in a direction parallel to the surface of the substrate and perpendicular to the vibration direction (Y direction), the beam structure 3
Coriolis force is generated in a direction perpendicular to the surface of the substrate with respect to the mass parts 309 and 310 of the parts 07 and 308. The displacement of the mass portions 309 and 310 of the beam structures 307 and 308 due to the Coriolis force indicates that the mass portions 309 and 310 and the back surface electrode 31
Capacitance C between 1,312. Is detected as a change.

Here, the Coriolis force fc is equal to the beam structure 30.
It depends on the mass m of the mass portions 309 and 310 of 7,308, the speed V of vibration, and the yaw Ω, and is expressed by the following equation. fc = 2 mVΩ (1) In general, since the Coriolis force is very small, the effect of resonance is used. Specifically, in order to increase the vibration velocity V shown in the equation (1), the mass parts 309 of the beam structures 307, 308,
The amplitude of the excitation 310 (in the Y direction parallel to the surface of the substrate) is set as the resonance frequency and the amplitude is increased. The amplitude at the time of resonance is mainly determined by air damping. The larger the damping coefficient by air damping, the smaller the amplitude. In general, a comb tooth structure has a large damping coefficient due to air damping, and it is difficult to obtain a large amplitude in the atmosphere. Therefore, a method of placing a vibrator in a vacuum package is often used, but this is difficult as a processing technique, is expensive, and has poor durability.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an angular velocity sensor capable of suppressing the influence of air damping and capable of driving a large-amplitude electrostatic drive in the atmosphere using a comb structure. It is in.

[0005]

According to a first aspect of the present invention, a driving force is applied to the primary vibrator main body to cause the primary vibrator main body to vibrate, and the secondary vibrator main body to be driven. Vibrates in the same direction as the primary vibrator main body due to vibration transmission from the primary vibrator main body. Then, when the secondary vibrator body is vibrating, the acceleration sensor element detects Coriolis force accompanying the application of the angular velocity.

Here, the primary vibrator is easily affected by air damping, while the secondary vibrator is not easily affected by air damping. More specifically, it is known that the amplitude at resonance is greatly affected by air damping, and the amplitude at resonance becomes smaller as the air damping (damping coefficient due to air damping) becomes larger. When the vibrator has a comb structure like a normal electrostatically driven vibrator, the vibrator is easily affected by air damping, but the secondary vibrator is relatively less affected by air damping.

In this manner, the influence of air damping is suppressed, and in particular, electrostatic drive in the atmosphere and large-amplitude drive using a comb structure can be realized. Here, as described in claim 11, a vibration system formed by the primary and secondary vibrator bodies is:
The vibration system is driven at a frequency with a large resonance magnification. This can be achieved by driving the vibrating system formed by the primary and secondary vibrator bodies at a frequency close to the natural frequency of at least one natural vibration mode.
At this time, the resonance magnification of the vibration system increases, and a large amplitude can be obtained.

On the other hand, when the structure as described in claim 12 is adopted, the primary vibrator main body vibrates by applying a driving force to the primary vibrator main body, and the secondary vibrator main body vibrates. Vibration is transmitted in the same direction as the primary vibrator main body by vibration transmission from the main vibrator. Then, when the secondary vibrator body is vibrating, the displacement detecting means detects the displacement of the secondary vibrator main body in a direction orthogonal to the vibration direction due to the Coriolis force accompanying the application of the angular velocity.

Here, the primary vibrator is easily affected by air damping, while the secondary vibrator is not easily affected by air damping. More specifically, it is known that the amplitude at resonance is greatly affected by air damping, and the amplitude at resonance becomes smaller as the air damping (damping coefficient due to air damping) becomes larger. When the vibrator has a comb structure like a normal electrostatically driven vibrator, the vibrator is easily affected by air damping, but the secondary vibrator is relatively less affected by air damping.

In this manner, the influence of air damping is suppressed, and in particular, electrostatic drive in the atmosphere and large-amplitude drive using a comb structure can be achieved. Here, as described in claim 16, the displacement detecting electrode is connected from the secondary vibrator main body by a vibration transmitting beam, and the root of the displacement detecting electrode is fixed to a fixed portion. They are connected by beams extending in the driving direction. Then, the secondary vibrator main body vibrates. However, since the base of the displacement detecting electrode is connected to the fixed portion by the beam extending in the driving direction, the driving vibration of the secondary vibrator main body is displaced by the displacement detecting electrode. Is suppressed. As a result, the angular velocity can be detected with high accuracy by detecting only the displacement component of the secondary vibrator main body.

Here, as described in claim 23, a vibration system formed by the primary and secondary vibrator bodies is driven at a frequency having a large resonance magnification of the vibration system. This means
This can be achieved by driving at a frequency close to the natural frequency of at least one natural vibration mode in the vibration system formed by the primary and secondary vibrator bodies. At this time,
The resonance magnification of this vibration system increases, and a large amplitude can be obtained.

In the invention according to claim 24, the angular velocity sensor according to claim 1 can be manufactured. That is, the primary and secondary holes are formed by the through holes formed in the semiconductor substrate.
This is preferable when partitioning the next vibrator body or the like. In addition, by being formed by a semiconductor process using a semiconductor substrate, reduction in size, weight, output, and cost can be achieved.

According to the twenty-seventh aspect, the angular velocity sensor according to the sixth aspect can be manufactured. That is, the primary and secondary holes are formed by the through holes formed in the semiconductor substrate.
This is preferable when the secondary vibrator is partitioned and a counter electrode is formed by the secondary vibrator main body and the movable electrode. In addition, by being formed by a semiconductor process using a semiconductor substrate, reduction in size, weight, output, and cost can be achieved.

According to the thirtieth aspect, the angular velocity sensor according to the twelfth aspect can be manufactured.
That is, this is preferable when the primary and secondary vibrator bodies and the like are partitioned by the through holes formed in the semiconductor substrate. In addition, by being formed by a semiconductor process using a semiconductor substrate, reduction in size, weight, output, and cost can be achieved.

In the invention according to claim 32, the angular velocity sensor according to claim 18 can be manufactured.
In other words, this is preferable when the primary and secondary vibrator bodies are defined by the through holes formed in the semiconductor substrate, and the fixed electrode and the secondary vibrator body constitute the opposing electrodes. In addition, by being formed by a semiconductor process using a semiconductor substrate, reduction in size, weight, output, and cost can be achieved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall schematic plan view of the angular velocity sensor according to the first embodiment. FIG. 3 shows A in FIG.
It is sectional drawing in the -A line. As shown in FIG. 3, the insulating film 5 and the wiring (77a and the like) are arranged on the silicon substrate (silicon chip) 1, but the insulating film 5 and the wiring (77a and the like) are omitted and only the silicon substrate 1 is provided. 2 is shown in FIG. In FIG. 1, the insulating film 5 is omitted to make the drawing easier to see.

As shown in FIG. 3, a concave portion 2 is formed on the rear surface (lower surface) of the central portion of the silicon substrate 1 having a rectangular shape. A thin portion 3 is formed on the bottom surface of the concave portion 2, and a thick rectangular frame portion 4 is formed around the thin portion 3 on four sides of the silicon substrate 1. In addition, the silicon substrate 1
An insulating film 5 is formed on the main surface (upper surface).

Here, the coordinate system in this embodiment is defined.
In the rectangular silicon substrate 1 in the plan views of FIGS. 1 and 2, the axis parallel to the long side is defined as the X axis, the axis parallel to the short side is defined as the Y axis, and the axis orthogonal to the XY coordinate plane is defined as the Z axis. I do.
Then, the X axis becomes the vibration axis (excitation direction) of the vibrator, and Z
The axis is the axis of the angular velocity to be detected, and the Y axis is the direction of detection of the Coriolis force.

As shown in FIG. 2, through-holes 6, 7, 8, 9, 10, 11 are formed in the thin portion 3 of the silicon substrate 1. The through holes 6 to 11 are formed by etching a part of the silicon substrate 1 from the surface to penetrate. The primary vibrator 1 is formed by the through holes 6 to 11.
2, 13 and the secondary vibrator 14 are sectioned. More specifically, regarding the oscillators 12, 13, and 14, the U-shaped 1
Next beams 15, 16, Primary vibrator body (weight portion) 17, 1
8, Primary oscillator movable electrodes 19, 20, 21, 22, 2
3, 24, 25, 26, fixed electrode 27, 2 for primary vibrator
8, 29, 30, 31, 32, 33, 34, U-shaped 2
Secondary beams 35 and 36, Secondary vibrator body (G sensor weight) 37
Are formed. The movable electrodes 19 to 26 and the fixed electrodes 27 to 34 have a comb shape.

The square frame portion 4 serves as a fixed portion of the vibrator, and primary vibrator main bodies 17 and 18 are connected to the square frame portion 4 by primary beams 15 and 16. Thus, the primary vibrator bodies 17 and 18 vibrate in the X direction by applying a driving force. In addition, 2
The secondary vibrator body 37 is connected by the secondary beams 35 and 36,
The primary vibrator main body 37 vibrates in the same X direction as the primary vibrator main bodies 17 and 18 by transmitting vibrations from the primary vibrator main bodies 17 and 18. That is, since the secondary vibrator main body 37 is connected by the U-shaped secondary beams 35 and 36, the secondary vibrator main body 37 is easily displaced (vibrated) only in the X direction and is hardly displaced in the Y and Z directions. .

Fixed electrodes 27 to 3 of primary vibrators 12 and 13
4 and the square frame part (fixing part) 4 are trench grooves 38, 39,
It is insulated by 40, 41, 42, 43, 44, and 45, and an insulator (for example, SiO ₂ or the like) is embedded therein. Further, as shown in FIG. 1, the fixed electrodes 27 to 34 are formed of metal wirings (for example, Al, T
i, etc.) 46, 47, 48, 49, 50, 51, 52, 5
3, the electrode terminals 46a, 47a, 48a, 49a, 5a arranged on the insulating film 5 in the square frame portion (fixed portion) 4.
0a, 51a, 52a and 53a, respectively. The fixed electrodes 27 to 34 and the metal wires 46 to
53 is a contact hole 54, 55, 56, 57, 5
8, 59, 60, 61 are in electrical contact.
That is, as shown in FIG. 3, a hole 62 is formed in a part of the insulating film 5 and filled with metal wiring (50, 51, etc.),
The upper and lower portions of the insulating film 5 are electrically contacted.

On the other hand, an acceleration sensor element 67 is provided on the secondary vibrator main body 37 so that the Coriolis force accompanying the application of angular velocity can be detected when the secondary vibrator main body 37 is vibrating. Has become. Specifically, as shown in FIG.
Through holes 63, 64, 65, and 66 are formed, and the acceleration sensor element 67 is defined by the through holes 63 to 66. Specifically, beams 68 and 69 for G sensor, G
Sensor movable electrodes 70 and 71, G sensor fixed electrode 7
2, 73 are sectioned. The movable electrodes 70 and 71 and the fixed electrodes 72 and 73 have a comb structure. Then, the movable electrodes 70, 71 connected by the beams 68, 69 face the fixed electrodes 72, 73 at a predetermined interval in a direction (Y direction) parallel to the surface of the substrate 1, and change in capacitance. Detects the angular velocity.

The fixed electrodes 72 and 73 of the secondary vibrator 14 are electrically insulated by trench grooves 74 and 75, respectively, and an insulator (for example, SiO ₂ or the like) is embedded therein. The fixed electrodes 72 and 73 are
As shown in FIG. 1, the secondary beams 3 are
5, 36, primary vibrator bodies 17, 18, primary beams 15, 1
6 and electrically contact with the electrode terminals 76a, 77a arranged on the insulating film 5 in the square frame portion (fixed portion) 4. However, in FIG. 1, an intermediate metal wiring is omitted. Further, the fixed electrodes 72 and 73 and the metal wiring 76,
77 is electrically connected by contact holes 78 and 79, respectively.

As shown in FIG. 2, projections 80 and 81 are formed on the secondary vibrator 14 and the rectangular frame (fixed portion) 4 opposed thereto.
The amplitude of the secondary vibrator main body 37 can be detected by monitoring the capacitance between them. That is, the fixed electrode 81 for monitoring the vibration is
They are arranged slightly apart from each other in the 0-axis and the Y-axis. The fixed electrode 81 is electrically insulated by a trench groove 82 and has an insulator (for example, SiO ₂ or the like) inside thereof.
Is embedded. This fixed electrode 81 is the same as that shown in FIG.
As shown in FIG. 7, the metal wiring 83 makes electrical contact with the electrode terminals 83a disposed on the insulating film 5 in the square frame portion (fixed portion) 4. The fixed electrode 81 and the metal wiring 8
3 is in electrical contact with the contact hole 84.

The movable electrodes 19 to 26 and 2 of the primary vibrator
The movable electrodes 70 and 71 of the next vibrator have trench grooves 38-4.
It is insulated from other electrodes by 5, 74, 75, and 82, and is in contact with the electrode terminal 85 by the contact hole 86.

Next, the operation of the angular velocity sensor thus configured will be described with reference to FIG. The movable electrodes 19 to 26 of the comb structure for driving are connected to GND (grounded), and a sinusoidal voltage with an offset is applied to one of the fixed electrodes 27, 29, 31, 33, and the other is fixed. Fixed electrodes 28, 3
0, 32 and 34 are applied with opposite phase sinusoidal voltages with the same offset. Thereby, the primary vibrator 1
2, 13 generate a sinusoidal vibration in the X-axis direction. At this time, the two primary vibrators 12 and 13 vibrate in the same phase.

Here, the vibration system formed by the primary vibrators 12, 13 and the secondary vibrator 14 has a natural vibration mode in which they vibrate in the same phase and a natural vibration mode in which they vibrate in the opposite phase. The frequency of the driving sine wave is made closer to one of these natural frequencies. As a result, the system resonates and a large amplitude can be obtained. The natural frequency (resonance frequency) is determined by the weight of the vibrator and the spring constant of the beam.

In FIG. 1, large and stable driving is realized by arranging the primary oscillators 12 and 13 on both sides of the secondary oscillator 14. As another configuration example in which the primary vibrator main bodies 17 and 18 are arranged on both sides of the secondary vibrator main body 37 as described above, one primary vibrator 12 is used as shown in FIG. It is also possible to configure a sensor, and in this case, there is an advantage that the chip size can be reduced.

Further, in this embodiment, the drive frequency is made to exactly match the natural frequency by using self-excited oscillation by the vibration monitor. That is, the change of the capacitance between the drive vibration monitor movable electrode 80 and the drive vibration monitor fixed electrode 81 with time is measured, and the drive frequency is adjusted so that the amplitude becomes maximum. The natural frequency varies depending on the temperature. However, if the self-excited oscillation by the driving vibration monitoring electrodes 80 and 81 is used, the driving can always be performed at the natural frequency. Further, according to the driving vibration monitoring electrodes 80 and 81, since the amplitude can be measured, the driving can be always performed with the same amplitude, and an angular velocity sensor having good temperature characteristics can be configured.

Incidentally, the amplitude at the time of resonance is greatly affected by air damping. It is known that the greater the air damping (and hence the damping coefficient), the smaller the amplitude at resonance. The primary vibrators 12 and 13 have comb-tooth structures 19 to 26 and 2 like ordinary vibrators driven by electrostatic force.
7 to 34, the secondary oscillator 14 is relatively susceptible to air damping, but the secondary vibrator 14 is relatively insensitive to air damping. Therefore, the secondary vibrator 14 can obtain a larger amplitude with the same voltage than that of the electrostatic drive using the normal comb structure. Since the magnitude of the Coriolis force is proportional to the driving amplitude, it is advantageous in increasing the output. Also,
Since the same drive amplitude as that of the related art can be obtained with a lower voltage or a smaller comb tooth structure than the related art, power saving or cost reduction can be expected.

As described above, in this embodiment, the electrostatic drive using the comb tooth structure is used as the driving means, but the driving method is not limited to the electrostatic drive using the comb tooth structure. It can be applied to a driving method.

On the other hand, when an angular velocity about the Z axis is applied to this sensor while the secondary vibrator 14 is vibrating in a sine wave in the X-axis direction, the weight of the acceleration sensor element (the secondary vibrator) The main body 37 receives a Coriolis force displaced sinusoidally in the Y-axis direction. As a result, the detection electrodes 70 and 72
The capacitance between the detection electrodes 71 and 73 changes sinusoidally. The change in the capacitance is measured using, for example, a synchronous detection circuit. Thereby, the magnitude of the angular velocity can be measured. Specifically, the Coriolis force fc
If the capacitance between the electrodes 70 and 72 becomes Co + ΔC (initial capacitance Co, the change ΔC due to the Coriolis force), the capacitance between the electrodes 71 and 73 becomes Co−ΔC (here, the Coriolis force). Is assumed to be much smaller than the initial gap).

Here, ΔC∝fc∝Ω (2) Since ΔC is proportional to yaw Ω, the capacitance between the electrodes 70 and 72 and the capacitance between the electrodes 71 and 73 are differentially calculated. By detecting, yaw Ω can be detected.

As another configuration example, as shown in FIGS. 7 and 8, two secondary vibrators 14 and 14 'are connected, and they are connected by beams 87 and 88 to vibrate in opposite phases. It may be. By taking the difference between the outputs of the acceleration sensor elements 67 formed on the two secondary vibrators 14, 14 ', disturbance acceleration can be filtered out. In this case, the acceleration can be measured by calculating the sum of the outputs of the acceleration sensor elements 67, and a sensor that simultaneously measures the acceleration and the angular velocity by signal processing can be configured. In this manner, two or more secondary vibrator bodies 37 can be connected by the beams 87 and 88.

The beams 15, 16,
Since 35, 36, and 87 are bent once or a plurality of times, they are preferable from the viewpoint of securing the degree of freedom of the vibrator body.

Next, a manufacturing process of the angular velocity sensor according to the present embodiment will be described with reference to FIGS. 4 and 5 show FIG.
FIG. 3 is a cross-sectional view corresponding to line AA of FIG.

First, as shown in FIG. 4A, a silicon wafer having a plane orientation (100) is prepared as the semiconductor substrate 1. Then, a silicon oxide film (SiO ₂ ) 90 is formed on the surface of the silicon substrate 1 by thermal oxidation. further,
A predetermined region of the silicon oxide film 90 is dug and an opening 9 is formed.
Is formed, and a trench 92 is formed in a predetermined region of the silicon substrate 1 by anisotropic etching using the mask as a mask.
Dig. Instead of forming the silicon oxide film 90 on the surface of the silicon substrate 1, the trench groove 92 may be dug at a similar position using a direct mask. This trench groove 92 becomes the trench grooves 38 to 45, 74, 75, and 82 in FIG.

After the formed silicon oxide film 90 is removed, a silicon oxide film (insulating film) 5 is newly formed on the surface of the silicon substrate 1 as shown in FIG.
The trench 92 is filled with the oxide film 5. If surface irregularities become a problem, the oxide film 5 is formed to have a thickness greater than the required thickness, and the surface is polished.

Thereafter, as shown in FIG. 4C, a predetermined region (unnecessary region) 93 of the silicon oxide film 5 is removed and a trench 62 is formed. Continuing with FIG.
As shown in FIG. 1A, a metal wiring such as Al or Ti is formed on the surface of the silicon substrate 1 by sputtering or electron beam evaporation and patterned. As a result, desired metal wiring 94 is arranged on oxide film 5 and trench groove 62 is formed.
Is buried to make contact with the silicon substrate 1.

Further, as shown in FIG. 5B, after an insulating film 95 such as SiO ₂ is formed on the entire back surface of the silicon substrate 1 and patterned, the back surface of the substrate 1 is anisotropically etched from the back surface. A predetermined region 96 is dug to form the concave portion 2 reaching the trench groove 92. As a result, this recess 2
A thin portion 3 is formed on the bottom surface of. At this time, it is important to protect the surface of the silicon substrate 1 with wax, resin, or the like in order to avoid damage.

Then, after removing the protection of the surface, as shown in FIG. 3, the thin portion 3 of the silicon substrate 1 is subjected to anisotropic etching from the surface, and through holes 6 to 11 (FIG. 2). As a result, primary and secondary vibrators (vibrator main bodies 17, 18, 37, etc.) are defined. Thus, the present sensor is completed.

As a result, this is preferable when the primary and secondary vibrators are separated by the through holes formed in the silicon substrate 1. Further, by forming the semiconductor substrate using a semiconductor process using the silicon substrate 1, it is possible to reduce the size, weight, output, and cost.

Although the silicon substrate 1 was used as the semiconductor substrate, the SOI substrate (Silicon on Silicon) was used as the semiconductor substrate.
Insulater) may be used. In this case, the hole penetrating the SOI substrate penetrates the buried insulating film and the thin silicon layer thereon.

As described above, this embodiment has the following features. (A) The secondary vibrator main body 37 is connected to the primary vibrator main bodies 17 and 18 by the secondary beams 35 and 36, and the primary vibrator main body 1 is connected.
Primary vibrator main bodies 17 and 18 by vibration transmission from
In addition to the vibration in the X direction, the acceleration sensor element 67 detects the Coriolis force accompanying the application of the angular velocity when the secondary vibrator main body 37 is vibrating. Therefore, the amplitude at resonance is greatly affected by air damping, and the larger the air damping (a damping coefficient due to air damping), the smaller the amplitude at resonance. However, the secondary vibrator is relatively less affected by air damping. It is hardly affected by air damping, and can be driven electrostatically and in a large amplitude in the atmosphere by a comb structure. (B) In the vibration system formed by the primary and secondary vibrator bodies 17, 18, and 37, if the drive frequency approaches the natural frequency of at least one natural vibration mode, the resonance magnification of this system increases. , A large amplitude can be obtained. (Second Embodiment) Next, a second embodiment will be described with reference to the first embodiment.
The following description focuses on the differences from this embodiment.

FIG. 9 is a schematic plan view of the angular velocity sensor according to the second embodiment. FIG. 11 is a sectional view taken along line BB of FIG. As shown in FIG. 11, a wiring 102 and a polysilicon layer 103 are arranged on a silicon substrate 100 with an insulating film 101 interposed therebetween.
FIG. 10 shows a sensor plan view of the silicon substrate 100 only, omitting the wiring 1, the wiring 102 and the polysilicon layer 103. In FIG. 9, the insulating film (nitride film) 101 in FIG. 11 is omitted for easy viewing.

In this embodiment, the X-axis on the XY coordinate plane (two-axis orthogonal coordinate plane) formed on the surface of the silicon substrate 100 is set as the driving vibration direction (excitation direction) of the vibrator, and Y
The axis is the axis of the angular velocity to be detected, and the Z axis is the direction of detection of the Coriolis force.

The acceleration sensor element 67 of this embodiment
Has a movable electrode 105. The electrode 105 is connected to the secondary vibrator main body 3 in the Z direction perpendicular to the surface of the substrate 100.
7 and is displaceably disposed at a predetermined interval. And the acceleration sensor element of this example is
The angular velocity is detected based on a change in capacitance using the movable electrode 105.

The details will be described below. As shown in FIG. 11, a concave portion 2 is formed on the back surface of the silicon substrate 100, and a thin portion 3 is formed on the bottom surface. And
In the thin portion 3, a part of the substrate 100 is etched from the surface to form a through hole 104, and as shown in FIG. 10, the primary oscillators 12, 13 and the secondary oscillator 1
4 are formed. Specifically, primary beams 15, 16,
Primary vibrator main body 17, 18, Primary vibrator movable electrode 19
26, a primary vibrator fixed electrode 27 to 34, and a secondary vibrator main body 37. Also, as shown in FIGS. 9 and 11, a polysilicon layer 10
G sensor weight 105 and G sensor beam 10
6,107 are formed. That is, G sensor weight 1
05 and the G sensor beams 106 and 107 are supported above the insulating film 101 at predetermined intervals. The G sensor weight 105 and the G sensor beams 106 and 107 are formed by sacrificial layer etching. The G sensor beams 106 and 107 are fixed to the insulating film 101 at anchor portions An (shown in FIGS. 9 and 11).

A capacitor is constituted by the secondary vibrator main body 37 and the G sensor weight 105, and the secondary vibrator main body 37 functions as a lower electrode of the acceleration sensor element. Further, a large number of etching holes 129 are formed in the G sensor weight 105, and an etching solution enters through the holes 129 when the sacrificial layer is etched.

As shown in FIG. 10, the primary vibrators 12, 1
The fixed electrodes 27 to 34 and the rectangular frame portion (fixed portion) 4 are insulated by trench grooves (nitride films) 38 to 45, and as shown in FIG.
01 to metal wirings 46 to 53 (for example, Al, Ti, etc.)
Thus, the electrode terminals 46 a to 53 a disposed on the nitride film 101 in the square frame portion (fixed portion) 4 are electrically in contact with each other. The fixed electrodes 27 to 34 and the metal wirings 46 to 53 are in electrical contact with each other through contact holes 54 to 61. That is, a hole is made in a part of the insulating film 101 and filled with metal, thereby electrically contacting the upper and lower parts of the insulating film 101. G sensor weight 105 on secondary vibrator 14
Are electrically insulated by trench grooves 108 and 109 as shown in FIG.
As a result, it passes through the upper part of the secondary beam 36, the primary vibrator body 18, and the primary beam 16, and makes electrical contact with the electrode terminal 110 a disposed on the nitride film 101 in the square frame part (fixed part) 4. (However, an intermediate metal wiring is omitted in FIG. 9).
The G sensor weight 105 and the metal wiring 110 are in electrical contact with each other through a contact hole 111.

As shown in FIG. 10, the fixed electrode 81 of the vibration monitor is electrically insulated by the trench groove 82. As shown in FIG. Is electrically in contact with the electrode terminal 83a disposed on the nitride film 101 of FIG. The fixed electrode 81 of the vibration monitor and the metal wiring 83 are in electrical contact with each other through a contact hole 84.

As shown in FIG. 10, the movable electrodes 19 to 26 of the primary vibrator, the secondary vibrator main body 37 and the movable electrode 80 of the vibration monitor are formed by trench grooves 38 to 45, 82, 10
The electrode terminals 113 are insulated from other electrodes by the metal wirings 8 and 109, and are arranged on the nitride film 101 in the square frame (fixed part) 4 by the metal wiring 113 as shown in FIG.
a (in FIG. 9, an intermediate metal wiring is omitted). The movable electrodes 19 to 26 of the primary vibrator, the secondary vibrator main body 37 and the movable electrode 80 of the vibration monitor are connected to the metal wiring 113 and the contact hole 114.
Are in electrical contact with each other.

Next, the operation of the angular velocity sensor according to the second embodiment will be described. The driving method is exactly the same as that of the first embodiment, and the description is omitted. In a state where the secondary vibrator main body 37 is vibrating sinusoidally in the X-axis direction,
When an angular velocity about the Y axis is applied to this sensor, the weight (movable electrode) 105 of the G sensor element receives a Coriolis force that displaces sinusoidally in the Z axis direction and displaces sinusoidally in the Z axis direction. As a result, the G sensor weight (movable electrode) 10
Since the capacitance formed by the fifth and second vibrator bodies 37 changes sinusoidally, the magnitude of the angular velocity can be measured by measuring the change using, for example, a synchronous detection circuit. In addition to the capacitance method, other methods such as electromagnetic detection and piezoelectric detection are possible.

In this embodiment, as in the first embodiment, the primary vibrator 1 is used as described with reference to FIG.
It is also possible to constitute this sensor with one piece of 2. Further, as described with reference to FIGS.
It is also possible to connect them and oscillate them in opposite phases. Furthermore, similarly to the first embodiment, the acceleration is measured by taking the difference between the outputs of the acceleration sensor elements of the two secondary vibrators, thereby filtering out the disturbance acceleration, and taking the sum of the outputs. It is possible to

Next, the manufacturing method will be described with reference to FIGS. 12, 13, and 14 are sectional views corresponding to line BB in FIG. First, as shown in FIG. 12A, a silicon wafer 100 having a plane orientation (100) is prepared as a semiconductor substrate, and a first trench 120 is dug in a predetermined region by anisotropic etching. This trench 1
Reference numeral 20 denotes trench grooves 38 to 45, 82, and 10 in FIG.
8,109.

Then, as shown in FIG. 12B, a silicon nitride film 101 as a first insulating film is deposited (formed) on the surface of the silicon substrate 100 to fill the trench 120 with the nitride film 101. . In the case where unevenness on the surface is a problem, the surface is polished by forming the nitride film 101 to have a thickness larger than a required thickness.

Further, as shown in FIG. 12C, a silicon oxide film 121 as a second insulating film is formed on the surface of the silicon substrate 100. This silicon oxide film 121
Is used as a sacrificial layer in a later step.

Subsequently, as shown in FIG. 12D, the substrate 100 is placed in predetermined regions of the oxide film 121 and the nitride film 101.
Dig the second trench groove 122 reaching. More specifically, a predetermined position of the oxide film 121 is removed, and then a predetermined position of the nitride film 101 is
22 is formed.

Then, as shown in FIG. 13A, a polysilicon layer 123 as a semiconductor layer is deposited (formed) on the surface of the silicon oxide film 121 to fill the trench groove 122 with the polysilicon layer 123. The polysilicon layer 123 buried in the trench 122 serves as an anchor portion An of the movable electrode 105 in FIGS. Then, FIG.
As shown in (b), an unnecessary region (predetermined position) 124 of the polysilicon layer 123 is removed by etching.

Subsequently, as shown in FIG. 13C, an unnecessary region (predetermined position) 125 of the silicon oxide film 121 is removed by etching. Then, as shown in FIG. 13D, a predetermined position of the nitride film 101 is removed by etching to form a third trench 126 reaching the silicon substrate 100.

Further, as shown in FIG. 14A, a metal wiring 127 of Al, Ti, or the like is formed on the silicon nitride film 101 by sputtering, electron beam evaporation, or the like to fill the trench 126. Thereafter, as shown in FIG. 14B, a nitride film 128 is formed on the entire back surface of the silicon substrate 100 and is patterned. Then, a predetermined position on the back surface is dug by anisotropic etching from the back surface of the silicon substrate 100 to form a recess 2 reaching the trench groove 120. As a result, a thin portion 3 is formed on the bottom surface of the concave portion 2. At this time, the surface is protected with wax, resin, or the like to avoid damage.

Then, after removing the protection of the surface, as shown in FIG. 14C, a through hole 104 is formed at a predetermined position in the thin portion 3 of the silicon substrate 100 by anisotropic etching from the surface. . Thereby, the primary and secondary oscillators 12, 13, 14 (the oscillator main bodies 17, 18, 37)
Etc.) are defined. Further, as shown in FIG. 14D, a predetermined position of the polysilicon layer 123 is removed, and a fourth trench groove (etching hole) 129 reaching the silicon oxide film 121 is formed. Then, the silicon oxide film 121 below the polysilicon layer 123 is removed by etching (sacrifice layer etching is performed), and as shown in FIG. 11, the polysilicon layer 123 serving as an upper electrode is made movable. Thus, the present sensor is completed.

As a result, the primary and secondary vibrators 12, 13, and 14 are defined by the through holes formed in the silicon substrate 100, and the secondary vibrator main body 37 and the movable electrode 105 constitute a counter electrode. In that case, it is preferable. In addition, by being formed by a semiconductor process using the silicon substrate 100, miniaturization, weight reduction, high output, and low cost can be achieved.

The silicon substrate 10 is used as a semiconductor substrate.
Although 0 is used, an SOI substrate may be used. (Third Embodiment) Next, a third embodiment will be described with reference to the first embodiment.
The following description focuses on the differences from this embodiment.

FIG. 15 is a schematic plan view of the angular velocity sensor according to the third embodiment. FIG. 16 shows C- in FIG.
It is sectional drawing in the C line. In this example, as shown in FIG. 16, a silicon layer 143 is formed on an SOI substrate 140, that is, a silicon substrate 141 via an insulating film (oxide film) 142.
Is used.

The axis of the angular velocity to be detected is a direction (Z axis) perpendicular to the surface of the SOI substrate 140. Further, as the driving means, an electrostatic drive with a comb-tooth structure is used as in the first and second embodiments.

In this embodiment, instead of the acceleration sensor element 67 in the first and second embodiments, the capacitance change detection electrode 15 as displacement detection means is used.
6, 157 are used, and the electrodes 156, 157 are installed in the square frame portion (fixed portion) 4. These electrodes 156, 157
When the secondary vibrator bodies 160, 161 are vibrating, the secondary vibrator main bodies 160, 1 in the Y direction orthogonal to the vibration direction due to the Coriolis force accompanying the application of the angular velocity are used.
61 is detected. More specifically, the variable capacitance change detection electrodes 156 and 157 are arranged opposite to the secondary vibrator main body 160 at a predetermined interval in the X direction parallel to the surface of the substrate 140, and are disposed in the secondary vibrator main body. 1
With 60, the counter electrode plate of the capacitor is formed.

The details will be described below. In FIG. 16, a concave portion 144 is formed on the back surface of the SOI substrate 140, and a thick rectangular frame portion 4 is formed on an outer peripheral portion thereof. A thin portion made of the silicon layer 143 is arranged on the bottom surface of the concave portion 144. In the silicon layer 143, a through hole 145 is formed, and the primary oscillators 12, 13 and the secondary oscillator 14 are partitioned as shown in FIG. More specifically, by forming through holes 145 and removing unnecessary regions of silicon layer 143 on oxide film 142, 1
Next beams 15, 16, Primary vibrator main bodies 17, 18, Primary vibrator movable electrodes 19-26, Primary vibrator fixed electrodes 27-
34, secondary beams 35, 36, 146, 147, secondary vibrator main bodies (movable electrodes for detection) 160, 161, and fixed electrodes 156, 157 for detection are arranged in a separated state, respectively.

The primary frame 15 and the primary beam 15
The next vibrator main bodies 17 and 18 are connected. Further, the secondary beams 35, 36 and 2
Secondary vibrator body 160, 1 through the secondary beams 146, 147
61 are connected. Here, the secondary beams 35 and 36 are U
The beam is shaped like a letter and can be displaced in the X direction. The secondary beams 146 and 147 extend linearly in the X direction and are displaceable only in the Y direction. Therefore, the secondary vibrator bodies 160 and 161 can be vibrated in the X direction by the secondary beams 35 and 36 and can be displaced in the Y direction by the secondary beams 146 and 147.

The fixed electrodes 2 of the primary vibrators 12 and 13
7 to 34 are insulated from other electrodes by the oxide film 142 of FIG. These are metal electrode terminals 148 to 155
Is electrically connected to the outside.

The fixed electrodes 156 and 157 for detection are insulated from other electrodes by the oxide film 142 of FIG. The fixed electrodes for detection 156, 157 are metal electrode terminals 158,
159 electrically connect with the outside.

The movable electrodes 19 to 26 for driving and the secondary vibrator bodies (movable electrodes for detection) 160 and 161 are insulated from other electrodes by the oxide film 142 in FIG. Drive movable electrodes 19 to 26, secondary vibrator main body (detection movable electrode) 1
60 and 161 are all at the same potential and are electrically connected to the outside by metal electrode terminals 162 or 163.

As described above, the primary vibrator bodies 17, 18
Are connected to the square frame portion (fixed portion) 4 by primary beams 15 and 16 and can be vibrated by applying a driving force. The secondary vibrator main bodies 160 and 161 are connected to the primary vibrator main body. Secondary beams 35, 36, 146, and 147 are displaceably connected to the primary vibrator main body 17, 18 in the Y direction orthogonal to the vibration direction. With the vibration transmitted from 18, the primary vibrator body 17,
It is possible to vibrate in the same X direction as 18.

In this embodiment, the secondary vibrator body 1
Primary vibrator main bodies 17 and 18 are arranged on both sides of 60 and 161. Furthermore, at least one beam 15, 16, 3
5 and 36 are bent once or a plurality of times (in FIG. 15, they are bent only once).

The primary and secondary vibrator bodies 17, 1
In the vibration system formed by 8, 160, and 161, if the driving frequency approaches the natural frequency of at least one natural vibration mode, the resonance magnification of this system increases, and a large amplitude can be obtained.

Next, the operation of the angular velocity sensor according to the third embodiment will be described. The driving method is exactly the same as that of the first embodiment, and the description is omitted. When an angular velocity about the Z axis is applied to this sensor while the secondary vibrator bodies 160 and 161 vibrate in a sinusoidal manner in the X-axis direction, the secondary vibrator bodies 160 and 161 become Y-axis. It receives a Coriolis force displaced sinusoidally in the direction, and displaces sinusoidally in the Y-axis direction. As a result, the detection electrodes 156 and 160
Since the capacitance between the detection electrodes 159 and 161 changes sinusoidally, it is possible to measure the magnitude of the angular velocity by measuring the change using, for example, a synchronous detection circuit. it can. At this time, the capacitance between the detection electrodes 156 and 160 and the capacitance between the detection electrodes 159 and 161 are differentially detected as in the first embodiment.

Incidentally, in addition to the electrostatic capacitance method, electromagnetic detection,
It is also possible to use a method such as piezoelectric detection, and in this case, it is also possible to dispose the displacement detecting element of the secondary vibrator main body not in the substrate but in a case that houses the substrate. Further, similarly to the first embodiment, as shown in FIG. 6, it is possible to configure this sensor with one primary vibrator. Further, as shown in FIGS. 7 and 8, it is also possible to connect two secondary vibrators and vibrate them in opposite phases. Further, as in the first embodiment, two or more secondary vibrator bodies are connected by beams, and the difference between the outputs of the detection units of the two secondary vibrators is obtained, thereby filtering out disturbance acceleration. By taking the sum of the output and the output, it is possible to measure the acceleration.

Next, the manufacturing process of the third embodiment will be described.
This will be described with reference to FIGS. 17 and 18 show FIG.
It is sectional drawing corresponding to CC line of FIG. First, FIG.
As shown in (a), the semiconductor substrate has a plane orientation (10
0) An SOI wafer (SOI substrate) 140 is prepared.
In other words, the second semiconductor layer 141 is formed on the silicon substrate 141 as the first semiconductor layer via the silicon oxide film 142 as the insulating film.
SOI in which a silicon layer 143 as a semiconductor layer is formed
A substrate 140 is prepared. Then, as shown in FIG. 17B, the SOI substrate 1 is formed by sputtering, electron beam evaporation, or the like.
A at a predetermined position on the surface of the silicon layer 143 at 40
A metal wiring 165 of l, Ti or the like is formed.

Then, as shown in FIG. 17C, a nitride film 166 is formed on the entire back surface, and etching is performed so that a predetermined position remains. Further, as shown in FIG. 18A, the unnecessary region 167 of the silicon layer 143 on the surface is removed by etching.

Thereafter, as shown in FIG. 18B, a predetermined position on the back surface of the silicon substrate 141 is dug by anisotropic etching to form a concave portion 144. As a result, a thin portion 168 is formed on the bottom surface of the recess 144. At this time, the surface is protected with wax, resin, or the like to avoid damage.

The thin portion 168 of the SOI substrate 140
On the other hand, as shown in FIG. 16, a through hole 145 is formed, that is, a predetermined position of the oxide film 142 is removed by etching, so that the primary and secondary vibrators 12, 13, 14 (vibrator main bodies 17, 18, 160, 161). Thus, the present sensor is completed.

As a result, it is preferable that the primary and secondary vibrators are separated by the through holes formed in the SOI substrate 140. In addition, by being formed by a semiconductor process using the SOI substrate 140, size reduction, weight reduction, high output, and low cost can be achieved.

The third embodiment can also be manufactured by a manufacturing process similar to that of the first embodiment. As described above, this embodiment has the following features. (A) As in the first and second embodiments, the amplitude at resonance is greatly affected by air damping, and the larger the air damping (a damping coefficient due to air damping), the smaller the amplitude at resonance. However, the secondary vibrator is relatively insensitive to the influence of air damping, the influence of air damping is suppressed, and the comb-shaped structure enables electrostatic driving in the atmosphere and large-amplitude driving. (Fourth Embodiment) Next, the fourth embodiment will be described in the third embodiment.
The following description focuses on the differences from this embodiment.

FIG. 19 is a plan view of the sensor according to the fourth embodiment. The driving method is exactly the same as in the third embodiment. The detection part is mainly different from the third embodiment. The axis of the detected angular velocity is the Z axis. Further, the electrodes are electrically separated as necessary in the same manner as in the third embodiment.

Displacement detecting electrodes 173 to 176 are connected from the secondary vibrator bodies 160 and 161 by vibration transmitting beams 171 and 172 extending linearly in the Y-axis direction.
Further, the root portion 18 of each of the displacement detecting electrodes 173 to 176.
3 and 184 are connected to the fixed portion 4 by beams 181 and 182 that extend linearly in the X-axis direction (the vibration direction).

The details will be described below. A comb-shaped fixed electrode 177 faces the comb-shaped electrode 173 of the secondary vibrator, and similarly, a comb-shaped fixed electrode 178 faces the comb-shaped electrode 174.
Are opposed to the comb-tooth electrode 175,
Are opposed to the comb-teeth electrode 176,
Are arranged respectively.

When an angular velocity about the Z axis is applied to this sensor while the secondary vibrator main bodies 160 and 161 vibrate sinusoidally in the X axis direction, the secondary vibrator main body 1
60 and 161 receive a Coriolis force displaced sinusoidally in the Y-axis direction, and displaced sinusoidally in the Y-axis direction. At this time,
Due to the presence of the beams 171 and 172, the movable electrode for detection 173 to
Similarly, 176 is displaced sinusoidally in the Y-axis direction. As a result, the capacitance between the detection electrodes 173 and 177, the capacitance between the detection electrodes 174 and 178, the detection electrode 175.1
Since the capacitance between 79 and the capacitance between detection electrodes 176 and 180 change sinusoidally, the change is measured using, for example, a synchronous detection circuit to measure the magnitude of the angular velocity. Can be.

At this time, as in the first embodiment, the capacitance between the detecting electrodes 173 and 177 and the detecting electrodes 174-1
The capacitance between 78 is detected differentially. Similarly, the capacitance between the detection electrodes 175 and 179 and the detection electrode 176.1
The capacitance between the 80 is differentially detected. In addition to the capacitance method, other methods such as electromagnetic detection and piezoelectric detection are possible.

On the other hand, the detection movable electrodes 173 to 176 are
Even if the secondary vibrator bodies 160 and 161 vibrate, the beams 181 and 1
Due to the rigidity of 82, no displacement occurs in the X-axis direction. As a result, the capacitance of the detection electrode does not change at all without the Coriolis force, so that noise can be suppressed.

In the structure of the third embodiment, it is also possible to simply make the detection electrode have a comb-teeth structure. However, in this case, since the detection electrode itself is easily affected by air damping, it is difficult to obtain a large amplitude drive which is an advantage of the present invention. Therefore, the present embodiment is advantageous in that a larger signal can be obtained than such a method.

Also in this embodiment, as shown in FIG. 6, it is possible to configure this sensor with one primary vibrator as in the first embodiment. Further, as shown in FIGS. 7 and 8, it is also possible to connect two secondary vibrators and vibrate them in opposite phases. Alternatively, as in the first embodiment, the acceleration is measured by filtering out the disturbance acceleration by taking the difference between the outputs of the detection units of the two secondary vibrators, and by taking the sum of the outputs. It is possible.

In the fourth embodiment, the electrodes can be appropriately separated and manufactured by the same manufacturing process as in the first and third embodiments. As described above, X
-The secondary oscillator main body 160 in the X-axis direction on the Y-coordinate plane;
161 vibrates, but the root portions 183 and 184 of the displacement detection electrodes 173 to 176 are moved by beams 181 and 181 extending in the driving direction.
Since it is connected to the fixed part 4 at 182, the driving vibration of the secondary vibrator main bodies 160 and 161
Transmission to 3 to 176 is suppressed. As a result, the angular velocity can be detected with high accuracy by detecting only the displacement components of the secondary vibrator bodies 160 and 161. (Fifth Embodiment) Next, a fifth embodiment will be described with reference to a third embodiment.
The following description focuses on the differences from this embodiment.

FIG. 20 is a plan view of the sensor according to the fifth embodiment. FIG. 22 is a sectional view taken along line DD in FIG. FIG. 23 is a sectional view taken along line EE in FIG. In this example, as shown in FIG. 22, an SOI substrate 190, that is, an SOI substrate 190 in which a silicon layer 193 is disposed on a silicon substrate 191 via an insulating film 192 is used. FIG. 21 shows a plan view of only the silicon substrate 191.

The axis of the angular velocity to be detected is the Y-axis direction which is parallel to the surface of the substrate 190 and orthogonal to the driving vibration direction. Unlike the third embodiment, the displacement detecting means uses an electrode 197 for detecting a change in capacitance.
As shown in FIG. 23, 97 is disposed opposite to the secondary vibrator main body 202 at a predetermined interval in the Z-axis direction perpendicular to the surface of the substrate 190.

Hereinafter, the details will be described. Figures 22 and 23
As shown in FIG. 19, an insulating film (silicon nitride film) 194 is formed on the SOI substrate 190. FIG.
As shown in FIG. 23, a concave portion 195 is formed by etching a part of the silicon substrate 191 from the surface, and the square frame portion 1 composed of four sides of the silicon substrate 191 is formed.
96 and a lower electrode 197 are defined. That is, FIG.
As shown in FIG. 1, the lower electrode 19 is provided inside the rectangular frame portion 196.
7 is constructed. Further, as shown in FIG. 23, a through hole 198 is formed in the silicon layer 193 at the bottom of the concave portion 195, and the through hole 198
As shown in FIG. 20, primary vibrators 12, 13 and secondary vibrator 199 are formed. For details, Primary beam 1
5, 16, primary vibrator main bodies 17, 18, primary vibrator movable electrodes 19 to 26, primary vibrator fixed electrodes 27 to 34,
The secondary beams 35 and 36 and the secondary vibrator main body 202 are sectioned.

The secondary beams 3 are attached to the primary vibrator bodies 17 and 18.
The secondary vibrator main body 202 is connected through 5, 36. Here, the secondary beams 35 and 36 are U-shaped, and
The thickness is thin, and the secondary vibrator main body 202 can be displaced (vibrated) in the X and Z directions.

Further, as shown in FIG.
The vibrators 12, 12, 199 are separated by the sacrificial layer etching process on the insulating film 192 of 90, and the lower electrode 197 is also separated from the secondary vibrator main body 202.

[0099] A large number of etching holes 202a are formed in the secondary vibrator main body 202, and an etching solution enters through the etching holes 202a when the sacrificial layer is etched.

As shown in FIG. 20, the primary vibrators 12, 1
The fixed electrodes 27 to 34 and the square frame portion (fixing portion) 196 are insulated by trench grooves (for example, nitride films) 38 to 45, and the fixed electrodes 27 to 34 are formed by metal wirings 46 to 34 on the nitride film 194. 53 (for example, Al, Ti, etc.) makes electrical contact with the electrode terminals 46 a to 53 a disposed on the nitride film 194 in the square frame portion (fixed portion) 196. The fixed electrodes 27 to 34 and the metal wirings 46 to 53 are appropriately electrically contacted by contact holes 54 to 61. In other words, the contact holes 54 to 61 are formed by making holes in a part of the insulating film 194 and filling them with metal, and serve to electrically contact the upper and lower parts of the insulating film 194.

Movable electrodes 19 to 26 and 2 of primary vibrator
The secondary vibrator body 202 is insulated from other electrodes by the trenches 38 to 45, and is in contact with the electrode terminal 200 by the contact hole 201.

Also, projections 80 and 81 are provided on the secondary vibrator main body 202 and the fixed portion 196 opposed thereto, respectively.
The capacitance during this period is monitored to detect the amplitude of the secondary vibrator body 202.

Next, the operation of the angular velocity sensor according to the fifth embodiment will be described. The driving method is exactly the same as that of the first embodiment, and the description is omitted. When an angular velocity about the Y-axis is applied to this sensor while the secondary vibrator main body 202 is vibrating sinusoidally in the X-axis direction, the secondary vibrator main body 202 is sinusoidally generated in the Z-axis direction. Receiving the displacing Coriolis force, it displaces sinusoidally in the Z-axis direction. As a result, the capacitance formed by the secondary vibrator body 202 and the lower electrode 197 changes sinusoidally, and the magnitude of the angular velocity is measured by measuring the change using, for example, a synchronous detection circuit. Can be. In addition to the capacitance, other methods such as electromagnetic detection and piezoelectric detection are possible.

As an application example, similarly to the first embodiment, it is possible to configure this sensor with one primary vibrator as shown in FIG. Also, as shown in FIGS.
It is also possible to connect two secondary vibrators and vibrate them in opposite phases. Similarly to the first embodiment, it is possible to filter out disturbance acceleration by taking the difference between the outputs of the detection units of the two secondary vibrators, and to measure the acceleration by taking the sum of the outputs. It is possible.

Next, the manufacturing process of the fifth embodiment will be described.
This will be described with reference to FIGS. 24 and 25 show FIG.
FIG. 4 is a sectional view corresponding to line DD of FIG. First, FIG.
As shown in (a), the semiconductor substrate has a plane orientation (10
An SOI wafer of 0) is prepared. That is, an SOI substrate 190 in which a silicon layer 193 as a second semiconductor layer is formed over a silicon substrate 191 as a first semiconductor layer via a silicon oxide film 192 as a first insulating film. Then, a first trench 210 is formed in the silicon layer 193 of the SOI substrate 190 by anisotropic etching. At this time, the etching is terminated when the silicon oxide film 192 is exposed. This trench groove 210 becomes the trench grooves 38 to 45 in FIG.

Then, as shown in FIG.
A silicon nitride film 194 as a second insulating film is deposited (formed) on the surface of the silicon layer 193 of the I-substrate 190 to fill the trench 210 with the nitride film 194. If unevenness on the surface becomes a problem, the nitride film 194 is formed to have a thickness larger than the required thickness, and the surface is polished.

Further, as shown in FIG. 25A, a predetermined position of the nitride film 194 is removed to form a trench groove 211 reaching the silicon layer 193. And FIG.
As shown in (b), a metal wiring 212 of Al, Ti or the like is formed on the nitride film 194 by sputtering, electron beam evaporation, or the like to fill the trench groove 211.

Subsequently, as shown in FIG.
A nitride film 213 is formed and patterned on the entire back surface of the OI substrate 190, a predetermined position is dug by anisotropic etching from the back surface, and the concave portion 1 reaching the silicon oxide film 192 is formed.
95 are formed. As a result, a thin portion 215 is formed on the bottom surface of the concave portion 195. At this time, the etching is terminated when the silicon oxide film 192 is exposed. At this time, the surface is protected with wax, resin, or the like to avoid damage.

Then, after removing the one whose surface is protected, as shown in FIG.
The nitride film 19 is anisotropically etched from the surface of
4 is removed, and the silicon layer 193 is removed.
Is removed to form a through hole 214. As a result, the primary and secondary vibrators (vibrator bodies 17, 18,
202 etc.) are formed.

Finally, as shown in FIG. 22, by removing a predetermined position (part) of the silicon oxide film 192 in the SOI substrate 190 (by performing sacrificial layer etching), the primary and secondary vibrators ( Vibrator bodies 17, 18,
202) is separated from the silicon substrate 191. Thereby, the present sensor is completed.

As a result, the primary and secondary vibrators are divided by the through holes formed in the SOI substrate 190, and
This is preferable when the counter electrode is constituted by the fixed electrode 197 and the secondary vibrator main body 202. In addition, by being formed by a semiconductor process using the SOI substrate 190, reduction in size, weight, output, and cost can be achieved.

In the above description, as shown in FIG. 2, the primary vibrator main body 17 (18) is connected to the fixed portion by the beam 15 (16), and the primary vibrator main body 17 (1) is connected.
The secondary vibrator main body 37 is connected to 8) by the beam 35 (36), but as shown in FIG. 26, the primary vibrator main body is connected to the fixed portion 4 via the primary beam 15 '(16'). 17 '(1
8 ′), and the primary vibrator body 17 ′ (1
8 '), a primary vibrator main body 17 "(18") is connected to the primary vibrator main body 17 "(18") via a primary beam 15 "(16"). Alternatively, the secondary vibrator main body 37 may be connected by the beam 35 (36).

[Brief description of the drawings]

FIG. 1 is a schematic plan view of an angular velocity sensor according to a first embodiment.

FIG. 2 is a plan view of a main part of FIG. 1;

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is a cross-sectional view for explaining a manufacturing process.

FIG. 5 is a cross-sectional view for explaining a manufacturing process.

FIG. 6 is a schematic plan view showing an application example of the first embodiment.

FIG. 7 is a schematic plan view showing an application example of the first embodiment.

FIG. 8 is a schematic plan view showing an application example of the first embodiment.

FIG. 9 is a schematic plan view of an angular velocity sensor according to a second embodiment.

FIG. 10 is a plan view of a main part of FIG. 9;

FIG. 11 is a sectional view taken along line BB of FIG. 10;

FIG. 12 is a cross-sectional view for explaining a manufacturing process.

FIG. 13 is a cross-sectional view for explaining a manufacturing process.

FIG. 14 is a cross-sectional view for explaining a manufacturing process.

FIG. 15 is a schematic plan view of an angular velocity sensor according to a third embodiment.

FIG. 16 is a sectional view taken along line CC of FIG. 15;

FIG. 17 is a cross-sectional view for explaining a manufacturing process.

FIG. 18 is a cross-sectional view for explaining a manufacturing process.

FIG. 19 is a schematic plan view of an angular velocity sensor according to a fourth embodiment.

FIG. 20 is a schematic plan view of an angular velocity sensor according to a fifth embodiment.

FIG. 21 is a plan view of a main part of FIG. 20;

FIG. 22 is a sectional view taken along line DD of FIG. 20;

FIG. 23 is a sectional view taken along line EE of FIG. 20;

FIG. 24 is a cross-sectional view for explaining a manufacturing process.

FIG. 25 is a cross-sectional view for explaining the manufacturing process.

FIG. 26 is a schematic plan view of another example of the angular velocity sensor.

FIG. 27 is a schematic view showing a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Silicon substrate, 2 ... recessed part, 3 ... Thin part, 4 ... Square frame part, 5 ... Insulating film, 6-11 ... Through-hole, 12, 13 ... Primary oscillator, 14 ... Secondary oscillator, 16 ... Primary beams, 17, 18
... Primary vibrator body, 19 to 26... Primary vibrator movable electrode, 27 to 34... Primary vibrator fixed electrode, 35, 36.
Secondary beam, 37 ... secondary vibrator main body, 63-66 ... through hole,
67: acceleration sensor element, 68, 69: beam for G sensor, 70, 71: movable electrode for G sensor, 72, 73 ...
G sensor fixed electrode, 80 ... movable electrode, 81 ... fixed electrode, 87, 88 ... beam, 92 ... trench groove, 93 ... unnecessary area, 94 ... metal wiring, 100 ... silicon substrate, 101 ...
Silicon nitride film, 104 through hole, 105 G sensor weight, 120 trench groove, 121 second insulating film, 12
2 ... trench groove, 123 ... polysilicon layer, 124, 1
25: unnecessary region, 126: trench groove, 127: metal wiring, 129: groove, 140: SOI substrate, 141: silicon substrate, 142: insulating film, 143: silicon layer, 144
... Recesses, 145 through holes, 146, 147 secondary beams, 1
56, 157: fixed electrode for detection, 160, 161: fixed electrode for detection, 165: metal wiring, 167: trench groove,
171, 172: beam, 173 to 176: movable electrode for detection, 181, 182: beam, 190: SOI substrate, 191
... Silicon substrate, 192 ... Insulating film, 193 ... Silicon layer, 194 ... Second insulating film, 195 ... Concave part, 196 ... Square frame part, 197 ... Lower electrode, 198 ... Through hole, 202 ...
Secondary vibrator main body, 210... First trench groove, 211.
Second trench groove, 212: metal wiring, 215: thin portion.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Nobuyuki Oya 1-1-1 Showa-cho, Kariya-shi, Aichi F-term in DENSO Corporation (Reference) 2F105 BB20 CC04 CD03 CD05 CD13 4M112 AA02 BA07 CA24 CA26 CA36 DA02 EA02

Claims (33)

[Claims] 1. A primary beam (15, 1) for a fixed part (4).
A primary vibrator body (17, 18) connected at 6) and vibrating by applying a driving force; and a secondary beam (3) with respect to the primary vibrator main body (17, 18).
5, 36), and the primary vibrator body (17,
18), the primary oscillator main body (17,
Secondary vibrator body (37) vibrating in the same direction as (18)
An acceleration sensor element (6) installed on the secondary vibrator main body (37) and detecting Coriolis force accompanying the application of angular velocity when the secondary vibrator main body (37) is vibrating;
7) An angular velocity sensor comprising: 2. The angular velocity sensor according to claim 1, wherein the driving means uses an electrostatic drive having a comb structure. 3. The angular velocity sensor according to claim 1, wherein the axis of the detected angular velocity is a direction perpendicular to the surface of the substrate (1). 4. The acceleration sensor element (67).
Are movable electrodes (70, 70) connected by beams (68, 69).
And a fixed electrode facing the fixed electrode in a direction parallel to the surface of the substrate and detecting an angular velocity by a change in capacitance.
2. The angular velocity sensor according to 1. 5. The method according to claim 1, wherein the axis of the angular velocity to be detected is the substrate (100).
2. The angular velocity sensor according to claim 1, wherein the direction is parallel to the surface of the lens and perpendicular to the driving direction. 6. The acceleration sensor element (67).
The movable electrode (105) is disposed so as to be displaceable at predetermined intervals at a position facing the secondary vibrator body (37) in a direction perpendicular to the surface of the substrate (100). The angular velocity sensor according to claim 5, wherein the angular velocity sensor detects an angular velocity. 7. The angular velocity sensor according to claim 1, wherein the primary vibrator bodies (17, 18) are arranged on both sides of the secondary vibrator main body (37). 8. The angular velocity sensor according to claim 1, wherein two or more secondary vibrator bodies (37) are connected by beams (87, 88). 9. At least one beam (15, 16, 3)
9. The angular velocity sensor according to claim 1, wherein (5, 36, 87) is bent one or more times. 10. A projection (80, 81) is provided on each of the secondary vibrator main body (37) and the fixed portion (4) opposed thereto, and the capacitance between them is monitored to monitor the secondary vibrator main body (3).
The angular velocity sensor according to claim 1, wherein the amplitude of (7) is detected. 11. The primary and secondary oscillator bodies (1)
2. The angular velocity sensor according to claim 1, wherein the vibration system formed in (7, 18, 37) is driven at a frequency having a large resonance magnification of the vibration system. 12. A primary vibrator body (17, 18) which is connected to a fixed portion (4, 196) by primary beams (15, 16) and vibrates by applying a driving force; The secondary beam (3
5, 36, 146, 147) are connected so as to be displaceable in the vibration direction of the primary vibrator main body (17, 18) and in a direction orthogonal to the vibration direction.
7, 18), the primary vibrator main body (1
7, 18) vibrating in the same direction as the secondary vibrator body (16).
0, 161, 202) and the secondary vibrator main body in a direction orthogonal to the direction of vibration due to Coriolis force caused by the application of angular velocity when the secondary vibrator main body (160, 161, 202) is vibrating An angular velocity sensor comprising: displacement detection means (156, 157, 197) for detecting the displacement of (160, 161, 202). 13. The angular velocity sensor according to claim 12, wherein an electrostatic drive having a comb structure is used as the driving means. The axis of the angular velocity to be detected is the substrate (140).
The angular velocity sensor according to claim 12, wherein the direction is perpendicular to the surface of the sensor. 15. The displacement detecting means (156, 157).
The capacitance change detection electrode is disposed opposite to the secondary vibrator main body (160, 161) at a predetermined interval in a direction parallel to the surface of the substrate (140).
5. The angular velocity sensor according to 4. 16. Electrodes for detecting displacement (173 to 176)
Are connected from the secondary vibrator main body (160, 161) by vibration transmitting beams (171, 172), and the root portions (183, 18) of the displacement detecting electrodes (173 to 176) are connected.
The angular velocity sensor according to claim 15, wherein 4) is connected to the fixed portion (4) by beams (181, 182) extending in the driving direction. The axis of the angular velocity to be detected is set to the substrate (19).
The angular velocity sensor according to claim 12, wherein the direction is parallel to the surface of (0) and perpendicular to the driving direction. 18. The capacitance change means (197), which is disposed opposite to a secondary vibrator body (202) at a predetermined interval in a direction perpendicular to the surface of the substrate (190). The angular velocity sensor according to claim 17, which is a detection electrode. 19. The secondary vibrator main body (160, 161, 16)
The angular velocity sensor according to claim 12, wherein the primary vibrator main bodies (17, 18) are arranged on both sides of the angular velocity sensor (02). 20. The angular velocity sensor according to claim 12, wherein two or more secondary vibrator bodies are connected by a beam. 21. At least one beam (15, 16, 3)
21. The angular velocity sensor according to claim 12, wherein (5, 36) is bent one or more times. 22. A projection (80, 81) is provided on each of the secondary vibrator main body (202) and the fixed portion (196) facing the secondary vibrator main body, and the capacitance between them is monitored to monitor the secondary vibrator main body (202). The angular velocity sensor according to claim 12, wherein an amplitude of the angular velocity is detected. 23. The primary and secondary oscillator bodies (1)
7, 18, 160, 161, 202)
The angular velocity sensor according to claim 12, wherein the vibration system is driven at a frequency having a large resonance magnification. 24. A semiconductor device comprising: a first trench formed in a predetermined region on a surface of a semiconductor substrate;
Depositing an insulating film (5) on the surface of the semiconductor substrate (1) and filling the first trench groove (92) with the insulating film (5); and removing unnecessary regions (93) of the insulating film (5). Removing, forming a second trench groove (62), and further forming a metal wiring (94) filling the second trench groove (62) on the insulating film (5); The concave portion (2) reaching the first trench groove (92) by anisotropic etching from the back surface of 1).
Forming a thin portion (3) on the bottom surface of the concave portion (2); and forming a through hole (6-1) in the thin portion (3) of the semiconductor substrate (1).
1), a primary vibrator body (17, 18) vibrating in a direction parallel to the surface of the semiconductor substrate (1), and the primary vibrator connected to the primary vibrator body (17, 18). Forming a secondary vibrator body (37) that vibrates in the same direction as the vibrator bodies (17, 18). 25. The method according to claim 24, wherein a silicon substrate is used as the semiconductor substrate. 26. The method according to claim 24, wherein an SOI substrate is used as the semiconductor substrate. 27. A first trench (120) is formed in a predetermined region on a surface of a semiconductor substrate (100), and a first insulating film (1) is formed on a surface of the semiconductor substrate (100).
01) and filling the first trench groove (120) with a first insulating film (101); and forming a second insulating film (1) on the surface of the first insulating film (101).
21) and a semiconductor substrate (10) at a predetermined position on the first and second insulating films (101, 121).
0), a step of digging a second trench (122) reaching the second insulating film (122), and forming a semiconductor film (12) on the surface of the second insulating film (121).
3) depositing and filling the second trench groove (122) with a semiconductor film (123); removing unnecessary regions (124) of the semiconductor film (123); The unnecessary region (125) of 121) is removed, and the first insulating film (101) is further removed.
Forming a third trench groove (126) reaching the semiconductor substrate at a predetermined position; and forming a third trench groove (1) on the first insulating film (101).
26) a step of forming a metal wiring (127) filling the recess, and a recess (2) reaching the first trench groove (120) by anisotropic etching from the back surface of the semiconductor substrate (100). Forming a thin portion (3) on the bottom surface of (2); and forming a through hole (1) in the thin portion (3) of the semiconductor substrate (100).
04), and a primary vibrator body (17, 18) vibrating in a direction parallel to the surface of the semiconductor substrate (100), and the primary vibrator connected to the primary vibrator body (17, 18). Forming a secondary vibrator main body (37) vibrating in the same direction as the vibrator main bodies (17, 18); and reaching the second insulating film (121) at a predetermined position of the semiconductor film (123). Forming a fourth trench (129); and forming the second insulating film (12) under the semiconductor film (123).
(1) etching and removing the semiconductor film (123) to be an upper electrode to make it movable. 28. The method according to claim 27, wherein a silicon substrate is used as the semiconductor substrate. 29. The method according to claim 27, wherein an SOI substrate is used as the semiconductor substrate. 30. A second semiconductor layer (1) in a semiconductor substrate (140) in which a second semiconductor layer (143) is formed on a first semiconductor layer (141) via an insulating film (142).
Forming a metal wiring (165) on the surface of the semiconductor substrate (43); etching and removing an unnecessary area (167) of the second semiconductor layer (143); Forming a concave portion (144) by anisotropic etching of the semiconductor layer (141) and forming a thin portion (168) on the bottom surface of the concave portion (144); and forming a thin portion (168) on the semiconductor substrate (140). A primary vibrator body (17, 18) having a through hole (145) and vibrating in a direction parallel to the surface of the semiconductor substrate (140);
Forming a secondary vibrator main body (160, 161) connected to the primary vibrator main body (17, 18) and vibrating in the same direction as the primary vibrator main body (17, 18). Manufacturing method of angular velocity sensor. 31. An SOI substrate (1) as the semiconductor substrate.
The method according to claim 30, wherein (40) is used. 32. A first semiconductor layer (191) is formed on the first semiconductor layer (191).
The second semiconductor layer (193) via the insulating film (192)
A first trench (210) is formed in a predetermined region of the second semiconductor layer (193) in the semiconductor substrate (190) having the trench formed thereon.
Forming a second insulating film (19) on the surface of the second semiconductor layer (193).
4) depositing said first trench groove (210) in the second
A second trench groove (21) reaching the second semiconductor layer (193) at a predetermined position of the second insulating film (194).
1) and forming the second insulating film (194)
Forming a metal wiring (212) filling the second trench groove (211) thereon; and anisotropically etching the first insulating film (192) from the back surface of the first semiconductor layer (191). Forming a thin portion (215) on the bottom surface of the concave portion (195); and forming the second insulating film (194) in the thin portion (215) of the semiconductor substrate (190). ) And the second semiconductor layer (1).
A through hole (214) is formed in the semiconductor substrate (19).
0) vibrating in the direction parallel to the surface of the primary vibrator body (1)
7, 18) and a step of partitioning and forming a secondary vibrator main body (202) connected to the primary vibrator main body (17, 18) and vibrating in the same direction as the primary vibrator main body (17, 18). And removing a part of the first insulating film (192) from the semiconductor substrate (190) to form the primary and secondary oscillator bodies (17, 18, 202) into a first semiconductor layer ( 191). 33. An SOI substrate (1) as the semiconductor substrate.
The method for manufacturing an angular velocity sensor according to claim 32, wherein (90) is used.