JPH09211020A - Accelerometer - Google Patents

Abstract

(57) [Summary] [Problem] To provide a resonance type acceleration sensor which is applicable to a semiconductor process and is not affected by temperature change, noise mixing, etc. SOLUTION: An inertial body 2 that is movable by acceleration, a support beam 3 that supports the inertial body 2 and is deformed when the inertial body 2 is moved, an excitation portion 4 of a piezoelectric element installed adjacent to the support beam 3, and a piezoelectric element. A resonator 7 having a receiver 5 and a propagator 6 is provided, and when an acceleration is applied, a change in the vibration state caused by the deformation of the resonator 7 corresponding to the deformation of the support beam 3 is input to the exciter 4. Detected by the signal and the output signal from the receiving unit 5,
An acceleration sensor for measuring the applied acceleration,
This is an acceleration sensor represented by a configuration in which the wiring pattern connecting to the support beam 3 and the resonator 7 formed on the vicinity thereof is symmetrical.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration sensor for detecting and measuring acceleration of a vehicle or the like, and more particularly to a small size and high precision accelerometer using a high precision silicon substrate. The present invention relates to a structure and a manufacturing method.

[0002]

2. Description of the Related Art Recently, acceleration sensors have been actively developed, and various kinds of acceleration sensors have been proposed.

Among them, as an acceleration sensor for accurately detecting the acceleration of a direct current component, a so-called resonance type acceleration sensor, which receives the change in the resonance frequency of the vibration generated on the excitation side by utilizing the tension due to the deflection of the beam, is noted. Has been done.

The structure of a conventional resonance type acceleration sensor will be described below with reference to the drawings.

FIG. 13 is a configuration diagram of a conventional resonance type acceleration sensor, FIG. 13 (a) is a plan view of the conventional resonance type acceleration sensor, and FIG. 13 (b) is a sectional view taken along line AA. Is.

In FIG. 13, reference numeral 200 denotes a vibrating body, and 201
Is an inertial body, and the vibrating body 200 is composed of an exciting unit 202, a receiving unit 203, and a propagating unit 204.

The inertial body 201 is connected to the vehicle body side by a support beam 205. In such a configuration, when acceleration is applied, the inertial body 201 moves up and down to move the support beam 2
The vibrating body 200 expands and contracts as 05 bends.

Therefore, when the acceleration changes, the resonance frequency of the vibrating body 200 changes, and it becomes possible to measure the acceleration by detecting this frequency change.

In the case of such a configuration, the expansion and contraction of the vibrating body 200 is related to the tension applied to the vibrating body 200, and in order to prevent the directionality with respect to the acceleration from being exhibited, the vibrating body 20 is prevented.
0 needs to be subjected to tension only by the deformation of the support beam 205.

Further, conventionally, when processing is performed using a single crystal silicon substrate, boron, which is a p-type dopant, is diffused as an impurity, and an etchant having a different etching rate depending on the substrate conductor, such as ethylenediaminepyrocatechol (E).
The substrate was processed using DP) or KOH aqueous solution.

As the silicon substrate processed in this way, for example, Sensors and Actuators (Sensors and Actuators) are used.
sB, p. 212, (1993)).

[0012]

However, in the resonance type acceleration sensor having such a structure, when the silicon LSI forming process is used with the miniaturization of the acceleration sensor, there is a problem that the conventional problem does not occur due to miniaturization. Precise control is needed.

In particular, as the film thickness of each structure becomes thinner, thermal history generated in the process causes stress, resulting in uneven stress on the support beam, making it impossible to accurately detect acceleration. Become.

The stress due to such a thermal history causes the support beam to be deformed such as twisted when the stress from the wiring pattern is transmitted to the support beam unevenly.

When acceleration is applied to an acceleration sensor having a support beam having a twisted structure, an output signal having directionality with respect to the acceleration is generated.

Further, when the sensor itself is miniaturized, the signal detection region is also miniaturized, and the intensity of the output signal itself becomes small.

As a result, the capacitance between the parasitic wirings becomes large with respect to the output signal, so that the noise becomes large with respect to the output signal, that is, the output signal is attenuated by the capacitance between the parasitic wirings and the output signal is accurately measured. Can not be transmitted to.

Further, this inter-wiring capacitance occurs not only with respect to the parasitic wiring capacitance between the output signal lines but also with respect to the parasitic wiring capacitance between the output signal lines and the silicon substrate.

On the other hand, when the resonance type acceleration sensor is formed by using the silicon LSI forming process, the wiring material is usually formed by spatter deposition.

When the wiring is formed by sputter deposition, the position rate cannot be increased in the sputtering process, and thus it is impossible to increase the film thickness of the wiring in the process, but the wiring of a thin film thickness cannot be obtained. In the case of using, the wiring on the step is cut off, which causes wiring failure.

When a silicon LSI forming process is used, a large number of resonance type acceleration sensors are formed on the same substrate. Therefore, when forming an acceleration sensor having uniform characteristics, the resonance frequency characteristics are uniform on the wafer. However, the resonance frequency depends on the thickness of the resonator.

Since the sensitivity to acceleration depends on the bending amount of the support beam, the sensitivity also changes depending on the film thickness of the support beam.

Therefore, it is necessary to form two kinds of regions having different film thicknesses in the wafer with good controllability.

However, the processing of a silicon substrate by etching using an etchant has been applied to leave a desired region, but since the etching rate varies, it is used for the purpose of accurate control of the film thickness. I was never told.

Further, in the resonance type acceleration sensor,
A change in environmental temperature causes thermal expansion of the resonator, resulting in a change in tension of the resonator. A change in tension of the resonator causes a change in resonance frequency.

For example, it is known that the resonant frequency causes a change of 800 Hz per 1 ° C. temperature change.

When the change in the resonance frequency due to the temperature occurs, it becomes impossible to measure separately from the change in the resonance frequency due to the acceleration, which causes a problem that the accurate acceleration cannot be measured.

The present invention has been made to solve the above problems, and further improves the resonance type acceleration sensor so that it can be easily formed using a silicon LSI forming process and is small in size. The object is to provide a highly sensitive acceleration sensor.

[0029]

In order to solve the above problems, an acceleration sensor according to the present invention includes an inertial body that is movable by acceleration, a support beam that supports the inertial body and is deformed when the inertial body moves, and a support beam. Deformation of the resonator corresponding to the deformation of the supporting beam when an acceleration is applied, comprising a resonator having an excitation section made of a piezoelectric element, a receiving section made of the piezoelectric element, and a propagation section installed adjacent to the beam. The resonance type acceleration sensor that measures the applied acceleration by detecting the change in the vibration state of the resonator caused by the input signal to the excitation unit and the output signal from the reception unit is used as the basic configuration. , Alone or in any combination.

First, there is an acceleration sensor in which the support beam and the wiring pattern connecting to the resonance part formed on the vicinity thereof are symmetrical.

Next, the acceleration sensor has an impurity diffusion region between the wiring pattern connecting to the resonance part and the substrate.

Next, of the electrostatic capacitance between the pair of wiring patterns connected to the piezoelectric element of the receiving section, the electrostatic capacitance due to the interlayer insulating film other than the region corresponding to the piezoelectric element is the piezoelectric element on the receiving side. The acceleration sensor has a capacitance of 1/10 or less of the capacitance of the interlayer insulating film in the region corresponding to.

Next, among the wiring patterns that connect to the resonance portion, the wiring pattern of the portion that passes through the step formed by the piezoelectric element is an acceleration sensor that is wider than the wiring pattern on the flat region.

Next, there is an acceleration sensor having a temperature compensating sensor that outputs an output signal that responds to environmental changes but does not respond to acceleration changes.

Next, the wiring pattern for connecting to the resonance part is
The acceleration sensor includes a component that applies a force that deforms the support beam in a first direction, and a component that applies a force that deforms the support beam in a direction opposite to the first direction.

Finally, the propagation section and the inertial body are acceleration sensors formed by utilizing the impurity diffusion regions formed on the substrate.

With the above configuration, an acceleration sensor that is easy to form by using the silicon LSI forming process and that is small and has high sensitivity is provided.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION First, according to the present invention described in claim 1, an inertial body movable by acceleration, a support beam that supports the inertial body and is deformed when the inertial body moves, and the support beam are provided. A resonator having an exciting section made of a piezoelectric element, a receiving section made of the piezoelectric element, and a propagating section, which are installed adjacent to each other, is provided, and when acceleration is applied, deformation of the resonator corresponding to deformation of the support beam An acceleration sensor that measures the applied acceleration by detecting a change in the vibration state of the resonator that occurs due to an input signal to the excitation unit and an output signal from the reception unit, and is formed on the support beam and its vicinity. The wiring pattern for connecting to the resonating part has a symmetrical shape.

Here, as described in claim 2, the acceleration sensor may be formed using a single substrate, and the wiring pattern may have a symmetrical shape on the entire substrate.

With this structure, even if stress is applied to the support beam due to thermal history during the acceleration sensor formation process, the support beam will not be twisted. Therefore, accurate acceleration can be detected.

According to a third aspect of the present invention, an inertial body movable by acceleration, a support beam that supports the inertial body and is deformed when the inertial body moves, and is installed adjacent to the support beam. A resonator having a resonator having an excitation section made of a piezoelectric element, a reception section made of a piezoelectric element, and a propagation section, and a vibration state of the resonator caused by deformation of the resonator corresponding to deformation of the support beam when acceleration is applied. Is a sensor for measuring the applied acceleration by detecting the change of the signal from the input signal to the excitation part and the output signal from the reception part, the substrate is made of silicon, and the wiring pattern for connecting to the resonance part And an acceleration sensor having an impurity diffusion region between the substrate and the substrate.

Here, as described in claim 4, the impurity diffusion region may function as a 0-potential side signal line.

With this configuration, parasitic capacitance is not generated between the common signal line on the excitation side or the reception side and the substrate, and the output signal is not attenuated.

According to a fifth aspect of the present invention, an inertial body movable by acceleration, a support beam that supports the inertial body and is deformed when the inertial body moves, and is installed adjacent to the support beam. A resonator having a resonator having an excitation section made of a piezoelectric element, a reception section made of a piezoelectric element, and a propagation section, and a vibration state of the resonator caused by deformation of the resonator corresponding to deformation of the support beam when acceleration is applied. Is an acceleration sensor for measuring the applied acceleration by detecting a change in the input signal to the excitation unit and an output signal from the reception unit, and between the pair of wiring patterns connected to the piezoelectric element of the reception unit. Among the capacitances, the capacitance due to the interlayer insulating film other than the region corresponding to the piezoelectric element is 1/10 or less of the capacitance due to the interlayer insulating film in the region corresponding to the piezoelectric element. With the accelerometer That.

With such a configuration, even when the output signal is reduced due to the miniaturization of the signal detection area accompanying the miniaturization of the sensor, the noise component becomes large with respect to the output signal, or the output signal is parasitic wiring. It is possible to prevent the output signal from being accurately transmitted due to the attenuation due to the inter-capacitance.

According to a sixth aspect of the present invention, an inertial body movable by acceleration, a support beam that supports the inertial body and is deformed when the inertial body moves, and is installed adjacent to the support beam. A resonator having a resonator having an excitation section made of a piezoelectric element, a reception section made of a piezoelectric element, and a propagation section, and a vibration state of the resonator caused by deformation of the resonator corresponding to deformation of the support beam when acceleration is applied. An acceleration sensor that detects a change in the input signal to the excitation unit and an output signal from the reception unit, and measures the applied acceleration, in the wiring pattern that communicates with the resonance unit, by the piezoelectric element. The wiring pattern in the portion that passes through the formed step is an acceleration sensor that is wider than the wiring pattern on the flat region.

With such a configuration, even if the wiring material has poor coverage of the wiring material or the wiring material crosses over a high step when a wiring having a thin film thickness is used, the wiring on the step is broken and the wiring is defective. In addition, the area of the wiring can be reduced on the flat region, and the parasitic capacitance of the wiring can be reduced.

Further, according to the present invention as set forth in claim 7, an inertial body movable by acceleration, a support beam that supports the inertial body and is deformed when the inertial body moves, and is installed adjacent to the support beam. A resonator having a resonator having an excitation section made of a piezoelectric element, a reception section made of a piezoelectric element, and a propagation section, and a vibration state of the resonator caused by deformation of the resonator corresponding to deformation of the support beam when acceleration is applied. Is an acceleration sensor that measures the applied acceleration by detecting a change in the signal from the input signal to the excitation unit and the output signal from the receiving unit. Further, the acceleration sensor corresponds to the environmental change but does not correspond to the acceleration change. It is an acceleration sensor having a temperature compensation sensor that outputs an output signal.

Here, as described in claim 8, the temperature compensating sensor comprises a supporting beam which is deformed when the temperature changes, an exciting portion composed of a piezoelectric element installed adjacent to the supporting beam, and a piezoelectric element. A resonator having a receiving unit and a propagating unit is provided, and when the temperature changes, a change in the vibration state of the resonator caused by the deformation of the resonator corresponding to the deformation of the support beam is received as an input signal to the excitation unit. The temperature change may be measured by detecting the output signal from the unit.

With such a structure, it is prevented that the resonator thermally expands due to the change of the environmental temperature and the tension of the resonator changes, which causes the change of the resonance frequency and the error of the acceleration measurement. It becomes possible.

According to a ninth aspect of the present invention, an inertial body that is movable by acceleration, a support beam that supports the inertial body and is deformed when the inertial body moves, and is installed adjacent to the support beam. A resonator having a resonator having an excitation section made of a piezoelectric element, a reception section made of a piezoelectric element, and a propagation section, and a vibration state of the resonator caused by deformation of the resonator corresponding to deformation of the support beam when acceleration is applied. Is an acceleration sensor that measures the applied acceleration by detecting a change in the signal from the input signal to the excitation unit and the output signal from the reception unit, and the wiring pattern that connects to the resonance unit includes The acceleration sensor includes a component that applies a force that deforms in one direction and a component that applies a force that deforms in a direction opposite to the first direction.

With such a configuration, even when different wiring pattern constituent materials are used, the stresses applied to the support beams due to thermal history during the acceleration sensor forming process can be canceled each other, and Since there is no twist in the output, the output signal does not have directionality with respect to the acceleration, and accurate acceleration can be detected.

In the above structure, as described in claim 10, the propagating portion and the inertial body may be formed by utilizing the impurity diffusion region formed in the substrate.

Here, as described in claim 11, a support beam and a propagation part having different thicknesses are formed by etching using the different diffusion depths of the impurity diffusion regions in the silicon substrate as stop layers. May be.

With such a structure, it is possible to collectively form regions having different film thicknesses of the support beam and the propagating portion with good controllability by the impurity concentration of the impurity diffusion layer without depending on the etching rate. .

(Embodiment 1) Hereinafter, Embodiment 1 of the acceleration sensor of the present invention will be described in detail with reference to the drawings.

FIG. 1A is a plan view of the acceleration sensor according to this embodiment, and FIG. 1B is a perspective view showing a main part of the acceleration sensor.

In FIG. 1, 1 is a silicon substrate, 2 is an inertial body, 3 is a support beam, 4 is an exciting part, 5 is a receiving part, 6 is a propagating part, 7 is mainly an exciting part 4, a receiving part 5, and a propagating part. 6 is a resonator constituted by 6; 8 is an input signal line; 9 is an input side common signal line; 10 is an output signal line; 11 is an output side common signal line;
Is a piezoelectric element on the excitation side, 13 is a piezoelectric element on the receiving side, 14 is a through hole of a resonator for separating the resonator 7 from the silicon substrate 1, and 15 is a through hole.
Is an inertial body through hole for separating the inertial body from the silicon substrate 1. In addition, the input side common signal line 9 and the output side common signal line 1
Since 1 is for applying 0 potential, it is simplified as an integrated structure which is mutually connected.

2A and 2B are sectional views of the acceleration sensor according to the present embodiment. FIG. 2A is a sectional view taken along the line AA 'of FIG. 1, and FIG. 2B is a sectional view taken along the line BB' of FIG. Each figure is shown.

In FIG. 2, 16 is an interlayer insulating film.
Reference numeral 17 denotes a protective film, and 18 denotes an impurity diffusion layer. However, these are omitted in FIG. 1 and the silicon substrate 1 is shown.

Here, the wiring patterns of the input signal line 8, the input-side common signal line 9, the output signal line 10, and the output-side common signal wiring 10 are symmetrical with respect to the plane AA '. It is preferable that these patterns are entirely symmetrical on the silicon substrate 1 in order to suppress the influence of thermal history in the manufacturing process described later. However, since the support beam 3 is bent on the support beam 3, it is even. It is important that the support beam 3 and the vicinity thereof have a symmetric shape so as to generate a flexure.

A method of manufacturing the acceleration sensor having the above structure will be specifically described below. 3A to 3D are explanatory views showing a manufacturing process using a cross-sectional view of the acceleration sensor of this embodiment.

In FIG. 3, the same members as those in FIGS. 1 and 2 are denoted by the same reference numerals, 32 is a silicon nitride film, 33 is a nitride film mask, 34 is a boron-containing diffusion agent, 35 is a boron impurity diffusion layer, 36 is a silicon nitride film mask, 37 is a boron-containing diffusing agent, and 38 is a backside etching mask. The boron impurity diffusion layer 35 uses boron for the impurity diffusion layer 18 shown in FIGS.

First, as shown in FIG.
0) on the silicon substrate 1 having the substrate plane orientation of 0)
The silicon nitride film 32 is formed by the D method. Shape in this case
The formation conditions are: CVD drive output (RF Power): 20
0W, reaction gas flow rate ratio: SiH _Four/ NHt_Three/ N_Two= 10
/ 30 / 100sccm, vacuum degree: 100Pa, substrate temperature
Silicon by plasma CVD method at a temperature of 300 ° C
The nitride film 32 is formed to a film thickness of 2 μm.

Next, a photoresist is spin-coated thereon with a film thickness of 1.5 μm by a spin coater.

Thereafter, the photoresist is exposed using a photomask so that the region where boron is diffused is opened,
develop.

Then, using the photoresist as a mask, phosphoric acid is used as an etchant for etching removal,
A silicon nitride film mask 33 is formed by opening the silicon nitride film 32 in a region corresponding to the opening of the photoresist.

Thereafter, as shown in FIG. 3B, a boron-containing diffusing agent 34 (manufactured by Tokyo Ohka: product name PBF) is spin-coated to form a film on the silicon substrate 1 and the nitride film mask 33.

Then, as shown in FIG. 3C, heat treatment is performed in a nitrogen atmosphere at 1155 ° C. for 25 hours to form a boron impurity diffusion layer 35a.

Next, the boron-containing diffusing agent 34 is added to HF: NH.
₄ F = 1: 5 Wet etching was performed using buffered hydrofluoric acid, and the silicon nitride film mask 33 was removed by wet etching using phosphoric acid. After that, as in FIG. Then, a silicon nitride film is formed, and a portion corresponding to the boron diffusion region is opened again to form the remaining silicon nitride film mask 36.

After that, the boron-containing diffusing agent 37 is added to FIG.
Spin coat as in (b), 1155 in nitrogen atmosphere.
Heat treatment is performed at 5 ° C. for 5 hours to form a boron impurity diffusion layer 35b shallower than that in FIG.

As a result, the boron impurity diffusion layers 35a and 35b having two kinds of depths are formed in the silicon substrate 1.

Then, as shown in FIG. 3D, the boron-containing diffusing agent 37 and the silicon nitride film mask 36 are similarly removed by wet etching.

Then, an Al film having a film thickness of 800 nm was formed by driving output (RF Power): 1 kW, Ar gas flow rate: 1
After deposition by sputter deposition under the conditions of 5 sccm and a vacuum degree of 18 mTorr, a photoresist is spin-coated with a film thickness of 1.5 μm by a spin coater, and then the photoresist is photo-coated to obtain a desired wiring pattern. Exposure and development are performed using a mask.

Then, using the photoresist as a mask, A
The I film is patterned by wet etching with phosphoric acid, and common signal lines 9 and 1 common to the input side and the output side are formed.
Form one.

On the common signal lines 9 and 11, drive output (RF Power): 100 W, gas flow rate: Ar /
O ₂ = 5/5 sccm, vacuum degree: 100 mTorr, substrate temperature 300 ° C., ZnO having a film thickness of 1.5 μm was sputter-deposited, and then photoresist was spin-coated with a film thickness of 1.5 μm by a spin coater. Then, the photoresist is exposed and developed using a photomask so that a desired piezoelectric pattern can be obtained. Then, using the photoresist as a mask, the ZnO film is patterned by wet etching using acetic acid to form the piezoelectric element 1 on the excitation side.
2 and the receiving side piezoelectric element 13 are formed.

Subsequently, the CVD drive output (RF Pow)
er): 100 W, reaction gas: SiH ₄ / N ₂ O = 10 /
150 sccm, vacuum degree: 100 Pa, substrate temperature 300
A silicon oxide film having a film thickness of 1 μm is deposited by a plasma CVD method under the condition of ° C. to form an interlayer insulating film 16.

After that, an Al film having a film thickness of 800 nm was formed by driving output (RF Power): 1 kW, Ar gas flow rate: 1
After depositing by sputter deposition under the conditions of 5 sccm and a vacuum degree of 18 mTorr, a photoresist is spin-coated with a spin coater to a film thickness of 1.5 μm, and then the photoresist is used as a photomask so that a desired wiring pattern can be obtained. To expose and develop. Then, using the photoresist as a mask, the Al film is patterned by wet etching with phosphoric acid to form the input signal line 8 and the output signal line 10.

Then, the drive output (RF Power
er): 100 W, reaction gas: SiH ₄ / N ₂ O = 10 /
150 sccm, vacuum degree: 100 Pa, substrate temperature 300
A protective film 17 is formed as shown in FIG. 3 (e) by depositing a silicon oxide film having a film thickness of 1 μm by a plasma CVD method under the condition of ° C. After that, a drive output is applied to the back surface of the silicon substrate 1. (RF P
ower): 200 W, reaction gas: SiH ₄ / NHt ₃ /
N ₂ = 10/30/100 sccm, vacuum degree: 100P
a, a silicon oxide film having a film thickness of 4 μm is deposited by the plasma CVD method under the conditions of the substrate temperature of 300 ° C.

Then, the photoresist is spin-coated with a spin coater to a film thickness of 1.5 μm, and then the photoresist is exposed and developed using the photomask so that a desired etching mask pattern can be obtained.

Then, using the photoresist as a mask, the silicon nitride film is patterned by wet etching with phosphoric acid to form a backside etching mask 38 as shown in FIG. 3 (f).

Finally, as shown in FIG. 3 (g), the substrate is etched with KOH aqueous solution of 40 wt% at 70 ° C. As a result, the boron impurity diffusion regions 35a and 35b have a slow etching rate, so that diffusion of Inertia through-holes 15 can be formed because regions of two different thicknesses depending on the depth remain without being etched, while regions where impurity diffusion is not performed are etched to the surface.
At this time, the resonator through hole 14 is also formed in the same manner.

Incidentally, in order to form regions having different film thicknesses in the silicon substrate, dry etching using a mask is possible without using the impurity diffusion layer for the etching stop.

However, in a structure such as an acceleration sensor, it is necessary to process the support beam region to a film thickness of about 20 μm and the resonator portion to a film thickness of about 5 μm. It is preferable to use the impurity diffusion layer rather than dry etching.

For example, when the dry etching process is used, the standard thickness of the 4-inch substrate is 400 μm.
Assuming a process in which etching is performed from the back surface of a silicon substrate having a thickness of m to leave a 20 μm silicon layer on the surface,
Since it is necessary to perform etching of 380 μm, if the general etching variation is estimated to be 10%, the etching error is 38 μm.

On the other hand, when the diffusion temperature is 1200 ° C., the diffusion
If a more etching stop layer is formed, the
The maximum temperature variation in the furnace is about ± 5 ° C. Easy
Therefore, if the temperature variation of the electric furnace is estimated to be ± 10 ° C,
Degree range is 1190-1210 ℃, diffusion coefficient square
If the root is 1200 ° C, 6.25 × 10^-1(Μ / hr
^-1/2), At 1190 ° C 5.87 × 10^-1(Μ
/ Hr^-1/2), 6.90 × 10 at 1210 ° C.^-1(Μ /
hr^-1/2) And a value with a variation.

Since the diffusion depth is proportional to the square root of the diffusion coefficient, when diffusion is performed at a diffusion temperature of 1200 ° C. and a depth of 20 μm, the variation in the diffusion depth due to the variation in the temperature of the electric furnace causes the variation in the temperature. It is 18.8 to 22.1 μm in proportion to the square root of the diffusion coefficient.

That is, for fine processing of the acceleration sensor, wet etching using the impurity diffusion layer as a stop layer is preferable to dry etching.

Further, in the case of forming two kinds of film thicknesses of the resonator portion to 5 μm and the support beam portion to 20 μm, 380 μm from the back surface of the silicon substrate having a film thickness of 400 μm in the case of a 4-inch substrate. It is necessary to form a pattern again after performing the etching of 1 and perform etching of 15 μm.

However, it is very difficult to form a pattern by forming a photoresist with a uniform film thickness on a step of 380 μm and then exposing the photoresist with high precision to form a pattern. On the other hand, it is possible to form a structure having two different film thicknesses by a method of forming a step by etching from both sides.

Specifically, in order to obtain two different film thicknesses of 20 μm and 5 μm, 5 μm at the initial stage of the process.
The region where the film thickness is desired to be obtained is etched to a depth of 15 μm from the surface side.

Then, in the final stage of the process, etching is performed from the rear surface side of the silicon substrate to 400 μm to 380 μm, which is the standard thickness of a 4-inch substrate, in both regions where film thicknesses of 20 μm and 5 μm are desired to be formed.

As a result, the film thickness was 5 μm in the region where 15 μm was etched from the front surface side and 380 μm was etched from the back surface side, while etching was not performed on the front surface side and only 380 μm was etched from the back surface side. In the region, a film thickness of 20 μm will be obtained.

According to this method, it is not necessary to form both etching patterns for forming two kinds of film thickness on a step, but even when such a method is used, the surface side has a thickness of 15 μm. There will be a step.

It is very difficult with the current technology to form a fine pattern such as a piezoelectric wiring on such a step on the front surface side without causing disconnection.

Although the silicon nitride film is used as the impurity diffusion mask in the above manufacturing steps, a thick oxide film may be used.

Although this nitride film is formed by the plasma CVD method, it may be formed by a thermal nitride film, a CVD nitride film or the like.

Further, although sputter deposition was used for depositing Al on the common signal line, the input signal line, and the output signal line, other deposition methods such as epitaxial growth and vapor deposition may be used.

Although the silicon oxide film is used as the interlayer insulating film, a silicon nitride film may be used.

Although the KOH aqueous solution is used as the etchant for the silicon substrate, a so-called EDP etching solution containing ethylenediamine, pyrocatechol and water may be used.

Although the silicon nitride film is used as the etching mask for the back surface of the silicon substrate, a thick oxide film may be used.

The case where the diffusion source having the same boron concentration is used to control the depth of the impurity diffusion layer by the diffusion time has been described. It is possible to form an impurity diffusion layer having a depth, and even if the thickness of the boron-containing diffusing agent is changed, the same result as when using a diffusion source having a different boron concentration is obtained.

Further, although boron diffusion was performed using a diffusion source coated on the surface, it may be performed using a gas source.

Now, the operation of the acceleration sensor constructed as described above will be described below, including the principle.

First, if an AC signal is applied between the input side signal line 8 and the input side common signal line 9, as a result, the excitation side piezoelectric body 12 vibrates with a frequency corresponding to the frequency of the AC signal. do.

Here, when the vibration generated in the excitation side piezoelectric body 12 matches the natural resonance frequency of the resonator 7, the vibration generated in the excitation side piezoelectric body 12 is amplified and the reception side piezoelectric element 13 is vibrated. Let

Then, the receiving piezoelectric element 13 that receives the vibration from the resonator 7 generates an AC signal having a frequency corresponding to the vibration frequency of the resonator 7, and the generated AC signal outputs the output signal line 10 and the output signal line 10. It is taken out as an output signal through the side common signal line 11.

On the other hand, when the resonance frequency is different from the natural resonance frequency of the resonator, the vibration generated in the excitation side piezoelectric body 12 is not efficiently transmitted to the reception side piezoelectric body 13 and the output from the reception side piezoelectric body is not generated. I can't really get it.

Therefore, it is understood that the resonance frequency of the resonator can be obtained by measuring the frequency of the AC signal applied to the input side piezoelectric element and the output of the output side piezoelectric element.

In the structure for performing such a principle operation, in FIG. 1, when acceleration is applied in the direction perpendicular to the paper surface, the inertial body 2 moves up and down in the direction of acceleration.

Due to the movement of the inertial body 2, the support beam 3 is bent with the inertial body 2 side being the moving end and the opposite side being the fixed end, and the resonator 7 is moved in the direction parallel to the plane of the drawing. Stretching motion occurs.

This expansion and contraction gives tension to the resonator 7, which causes the resonance frequency to increase when the tension increases, and decreases when the tension decreases.

Therefore, the acceleration can be measured by detecting this frequency change.

Here, as described above, the input signal line 8,
The wiring patterns of the input-side common signal line 9, the output signal line 10, and the output-side common signal wiring 10 are preferably entirely on the silicon substrate 1 with respect to the AA ′ plane, or at least on the support beam 3. It has a symmetrical shape in its vicinity.

Therefore, in the case where the silicon substrate 1 is made entirely symmetrical, the input signal line 8 material and the input side common signal line 9 material are also supported by the substrate 1 and the substrate 1 due to the thermal history during the acceleration sensor forming process. The substrate 1 and the support beam 3 are not deformed without applying stress to the beam 3, and further, when at least the support beam 3 has a symmetrical shape, the support beam 3 itself is caused by the thermal history during the acceleration sensor forming process. Does not cause twisting.

As described above, in the present embodiment, it becomes possible to detect an accurate acceleration by eliminating the output signal having directionality with respect to the acceleration.

(Second Embodiment) Next, as a second embodiment of the present invention, the capacitance characteristic of the acceleration sensor in the first embodiment will be described with reference to the drawings.

FIGS. 4A and 4B are schematic diagrams showing the regions where the capacitance of the acceleration sensor corresponding to the presence or absence of the impurity diffusion layer in this embodiment is generated.

In FIG. 4, in addition to the same reference numerals as in FIGS. 1 to 3, C ₁ is the input side interlayer insulating film capacitance, C ₂ is the input signal line capacitance, and C ₃ is the exciter capacitance. , C ₄ is the output side interlayer insulating film capacitance, C ₅ is the output signal line capacitance, C ₆ is the receiver capacitance, and 41 is the natural oxide film.

First, considering the capacitance generated in the acceleration sensor described in the first embodiment, on the input side, the input generated due to the interlayer insulating film 16 in the region corresponding to the excitation side piezoelectric element 12 is input. Corresponding to the side interlayer insulating film capacitance C ₁ , the input signal line capacitance C ₂ generated due to the interlayer insulating film 16 in the region other than the region corresponding to the excitation side piezoelectric element 12, and the excitation side piezoelectric element 12. The exciter capacitance C ₃ generated by the above is considered, and on the other hand, on the output side, the output side interlayer insulating film capacitance generated due to the interlayer insulating film 16 in the region corresponding to the receiving side piezoelectric element 13 is generated. C ₄ , an output signal line capacitance C ₅ generated corresponding to the interlayer insulating film 16 in a region other than the region corresponding to the reception side piezoelectric element 13, and a receiver static electricity generated corresponding to the reception side piezoelectric element 13. Consider the capacitance C ₆ It is.

Here, input directly on the silicon substrate 1,
When the common signal lines 9 and 11 which also serve as both the output side are formed, the oxygen component comes into contact with the silicon substrate 1 by the time the common signal lines 9 and 11 are formed, and a silicon oxide film region is formed on the surface thereof. The natural oxide film 41 is often formed.

In such a case, if a potential difference occurs between the silicon substrate 1 and the common signal lines 9 and 11 due to an external influence, the natural oxide film 41 causes a new capacitance component. I will end up.

That is, when such a natural oxide film is formed on the silicon substrate 1, a parasitic MOS structure is partially formed between the common signal line, the natural oxide film, and the single crystal silicon substrate. When the potential of the silicon substrate 1 below the region having the MOS structure becomes different from the potential of the common signal line due to external influences such as the mixing of noise, a parasitic capacitance is newly formed.

When such a new capacitance component is generated, a circuit as shown in FIG. 4A is generated and the driving conditions of the excitation side piezoelectric element 12 and the reception side piezoelectric element 13 are changed,
The resonance frequency change of the resonator that exactly corresponds to the acceleration to be measured cannot be obtained.

Therefore, as shown in FIGS. 1 to 3 and FIG. 4B, if an impurity diffusion layer 18 (35) is provided between the silicon substrate 1 and the common signal lines 9 and 11, a natural oxide film is formed. 41 can effectively suppress the generation of new capacitance. According to the study by the inventor of the present application, a new capacitance is generated as shown in FIG.
1 and the silicon substrate 1 are significantly different in resistance value, a potential difference occurs due to an external influence across the natural oxide film 41, and the capacitance component of the natural oxide film 41 is correspondingly manifested. It is thought to be because of this.

Therefore, the common signal lines 9 and 11 are formed by diffusing appropriate impurities such as boron into the silicon substrate 1 to form the impurity diffusion layer 18 and adjusting the resistance values to be equal to the resistance values of the common signal lines 9 and 11. The impurity diffusion layer 18 and the impurity diffusion layer 18 become equipotential, an equivalent circuit as shown in FIG. 4B and the like is formed, and it is possible to effectively suppress the generation of new capacitance due to the natural oxide film 41. .

For example, in the present embodiment, if the manufacturing process of the acceleration sensor described in the first embodiment is used, in order to use the boron impurity diffusion layer as the etching stop layer, the boron impurity concentration is 10 ¹⁹ cm ^−3. As described above, when the boron impurity concentration is 10 ¹⁹ cm ⁻³ or more, the resistivity becomes 9 × 10 ⁻³ Ω · cm or less, which is suitable for use as a general wiring material.

On the other hand, when the silicon substrate is used as the common signal line without forming the impurity diffusion layer, the ordinary silicon substrate has a high resistivity of about 1 Ω · cm, so that it is practical to function as a signal line. It cannot be done.

The effect of the impurity diffusion layer is that the common potential (0 potential) is substantially provided even when the input side common signal line 9 and the output side common signal line 11 are not common. Of course, it is equally effective.

Next, the relationship between the electrostatic capacitances on the output side, which influence the magnitude of the output, will be examined.

FIG. 5 is an explanatory diagram showing only an equivalent circuit formed by each capacitance generated in the acceleration sensor described in the first embodiment. In addition, in FIG.
The potential is given by the integrated common signal lines 9 and 11.

In FIG. 5, V is the voltage of the output signal of the receiving piezoelectric element 13, and Vout is the voltage that can be actually obtained from the output signal line 10.

Here, V and Vout have a relationship represented by the following (Equation 1).

[0134]

[Equation 1]

Therefore, the ratio of the output signal line capacitance C ₅ formed outside the piezoelectric element and the output side piezoelectric film interlayer insulating film capacitance C ₄ determines the magnitude of the output signal.

The magnitude of this output signal depends on the environment in which the acceleration sensor is placed, for example, the amount of noise mixed in from the surroundings,
In addition, although it is determined by the performance of the output signal amplifier, in the case of the acceleration sensor using the configuration of the present embodiment, the voltage V of the output signal of the receiving side piezoelectric element 13 is 5 m in principle.
About V.

On the other hand, the noise component in the case of the acceleration sensor of the present embodiment has a noise component of about 0.1 mV. Generally, when the SN ratio is about 1/5 or more, the filter circuit is indispensable. .

However, since the voltage that can actually be obtained from the output signal line 10 is defined by (Equation 1), for example, the output signal line capacitance C ₅ is the output side piezoelectric film interlayer insulating film capacitance. When it is set to 10 times C _4, the voltage obtained from the output signal line is about 0.5 mV.

That is, when the output signal line capacitance C ₅ is 10 times the output side piezoelectric film interlayer insulating film capacitance C ₄ , the SN ratio is 1/5, so a filter circuit is required. It is conceivable that when these ratios are set to 10 times or less, the SN ratio becomes 1/5 or less, and it is understood that it is not necessary to provide a filter circuit.

In this way, the output signal line capacitance C ₅ is
By setting the capacitance on the output side interlayer insulating film C ₄ within 10 times, the acceleration sensor can be formed without using a filter circuit.

As described above, in the present embodiment, by providing the impurity diffusion layer in the silicon substrate, the capacitance of the natural oxide film generated at the interface between the silicon substrate and the common signal line which gives 0 potential is transferred. It is possible to eliminate the influence of the above and to perform more accurate acceleration measurement, and the capacitance due to the interlayer insulating film other than the area corresponding to the receiving side piezoelectric element is the interlayer insulating film in the area corresponding to the receiving side piezoelectric element. Since the capacitance is a predetermined value, the influence of the attenuation of the output signal due to the capacitance between the parasitic wirings can be effectively eliminated, and an accurate output signal with a large SN ratio can be obtained.

In particular, even if the output signal tends to decrease due to the miniaturization of the signal detection area accompanying the miniaturization of the acceleration sensor, it is possible to sufficiently cope with the situation.

(Third Embodiment) Next, as a third embodiment, a method of arranging the wiring pattern of the acceleration sensor in the first embodiment will be described with reference to the drawings.

FIG. 6 is a configuration diagram representatively showing a wiring pattern for the receiving side piezoelectric element 13, and L1 shows a connecting portion where the output signal line 10 communicates with the receiving side piezoelectric element 13, and L
Reference numeral 2 denotes a portion disposed on the inner plane thereof, and L3 denotes a portion of which the shape changes in the vertical direction in order to communicate with the receiving piezoelectric element 13.

In the present embodiment, the output signal line 10
The output common signal line 11 is made of Al and has a film thickness of 600 n.
m, and the receiving side excitation element 13 was formed using ZnO to a film thickness of 2 μm.

Therefore, when the acceleration sensor is formed with such a film thickness structure, the output signal line 10 needs to overcome the step difference of 2 μm formed by the receiving side excitation element 13.

The presence of the step of 2 μm means that the Al wiring has a sufficiently thick film thickness, for example, a film thickness of 2 μm or more, or a deposition method that provides sufficient coverage in the step portion. If the side surface is vertical or has a forward taper, disconnection of the wiring does not occur and it is not a problem.

However, when the current silicon LSI process is used, the sputter deposition method is used.
When depositing l, it is difficult to deposit a thick Al film, it is difficult to process the side surface of the excitation element into a forward taper shape, and to deposit a step of 2 μm with good coverage. Tend to occur. Even when no wire breakage occurs, the wiring film thickness becomes thin at the step portion, and when the wiring thickness is the same at the step portion and the flat portion, the current density flowing in the wiring becomes high and Al When the wiring causes electromigration or the like, the reliability of the signal line is deteriorated.

Therefore, in the present embodiment, the connecting portion L for connecting the output signal line 10 to the receiving side piezoelectric element 13 is used.
1, the portion L2 arranged on the plane has a line width l1 with respect to the current direction and a portion L whose shape changes in the vertical direction.
In 3, the line width 12 is set thicker than 11 in the current direction.

As described above, with the structure of this embodiment, it is possible to prevent disconnection or breakage of the wiring and effectively improve the reliability.

In this embodiment, the wiring pattern for the receiving-side piezoelectric element 13 has been described, but the same applies to the wiring pattern for the excitation-side piezoelectric element.

When the wiring shape is not limited to the output signal line and the wiring shape changes three-dimensionally, the same configuration can be adopted.

(Fourth Embodiment) Next, as a fourth embodiment, a configuration in which a temperature compensation function is added to the acceleration sensor of the first embodiment will be described with reference to the drawings.

FIG. 7 is a block diagram showing the structure of the acceleration sensor according to the present embodiment. Reference numeral 71 is an acceleration sensor, 72 is a temperature compensation sensor, 73 is an arithmetic unit, and S
₁ the output signal from the acceleration sensor 71, S ₂ is the output signal from the temperature compensating sensor, the S _O is the output from the arithmetic unit 73.

In the acceleration sensor typified by the first embodiment, which detects acceleration by changing the resonance frequency, the resonance frequency changes depending on the temperature change.

Therefore, the output signal of the acceleration sensor includes not only the acceleration but also the temperature change component.

Therefore, in this embodiment, the temperature compensation sensor 72 and the arithmetic unit 73 are added, and the output signal S ₁ of the acceleration sensor 71 and the temperature compensation sensor 72 are added.
And the output signal S _{2 of}
In 3, the calculation of S _O = S ₁ −S ₂ is executed, and S _O is output as an output signal.

Therefore, by taking the difference between the output signal of the acceleration sensor 71 and the output signal of the temperature compensation sensor 72 in this way, it becomes possible to obtain the output signal of only the acceleration component.

Next, a preferred specific structure of the temperature compensation sensor 72 will be described. 8A and 8B are configuration diagrams showing the structure of the temperature compensation sensor, FIG. 8A is a plan view thereof, and FIG. 8B is a sectional view taken along the line AA '.

In FIG. 8, 81 is a silicon substrate, and 84 is
Is an exciting unit, 85 is a receiving unit, 86 is a propagating unit, 87 is a resonator mainly composed of an exciting unit 84, a receiving unit 85 and a propagating unit 86, 88 is an input signal line, 89 is an input side common signal line,
90 is an output signal line, 91 is an output side common signal line, 92 is an excitation side piezoelectric element, 93 is a reception side piezoelectric element, and 94 is a resonator 8.
A resonator through hole for separating 7 from the silicon substrate 81;
Is an interlayer insulating film, 97 is a protective film, and 98 is an impurity diffusion layer, but these are omitted in FIG. 8A. The input-side common signal line and the output-side common signal line are 0
Since it is for applying an electric potential, it is simplified as an integrated structure which is connected to each other.

That is, the temperature compensating sensor 72 has the same structure as the acceleration sensor 71 described in detail in the first embodiment, but the region corresponding to the inertial body is not separated from the silicon substrate, that is, it is movable. It has a structure without inertia.

Therefore, even if this sensor receives acceleration, the resonance body does not expand or contract, and the resonance frequency does not change due to acceleration.

On the other hand, when the environmental temperature changes, the resonator thermally expands and the resonance frequency changes.

As a result, the temperature characteristic of the resonance frequency is obtained by the temperature compensation sensor 72, and the difference in the resonance frequency between the acceleration sensor 71 and the temperature correction sensor 72 is obtained as the actual acceleration not including the temperature characteristic.

With the configuration of the present embodiment as described above, by using the temperature compensation sensor, accurate acceleration independent of temperature change can be measured, and the temperature compensation sensor and the acceleration sensor have the same basic configuration. In addition, cost reduction and quality stabilization can be achieved by using a common manufacturing method.

(Fifth Embodiment) Next, as a fifth embodiment, a configuration in which the wiring pattern of the acceleration sensor of the first embodiment is examined will be described with reference to the drawings.

FIG. 9 is a schematic diagram of the wiring pattern of the acceleration sensor formed in this embodiment, and 99 is a common signal line on the input and output sides.

The acceleration sensor having the configuration described in detail in the first embodiment has a function of applying an input signal to the exciter 4 so that the receiver 5 senses the vibration generated in the exciter 4 and outputs it as a signal. With
The common signal lines 9 and 11 on the input side and the output side are connected on the propagation section 6 and integrated.

Therefore, functionally, whether the input side or the output side is
It suffices to extend the wiring to either one, and it is not absolutely necessary to extend both the input side and output side wirings, and it is sufficient to extend only one side to connect it to 0 potential.

Specifically, for example, as shown in FIG. 9B, the extension of the input side common line is omitted, and the output side common signal line 11 shown in FIG. 9A is input and output. It may be used as the signal line 99. Of course, the input-side common signal line 9 may be used as the input / output signal line 99.

FIG. 10 shows a detailed structure using such an input / output common line 99. In FIG. 10, since the wiring pattern on the support beam 3 is formed on only one side, the wiring pattern for signal supply is not symmetrical with respect to the line AA ′.

That is, even in such an asymmetric structure in which the wiring pattern is formed only on one side of the support beam 3, it is possible to form the acceleration sensor in terms of an electric circuit.

However, when the wiring and the piezoelectric element are formed by using Al and ZnO by the sputter deposition method using the silicon LSI forming process, and the SiO ₂ protective film and the interlayer insulating film are formed by the plasma CVD method, respectively. Al exerts compressive stress on a silicon substrate, and ZnO and Si
O ₂ gives a tensile stress, and as shown in FIG. 10 (b), the deformation of the support beam 3 warps asymmetrically into a convex surface on one side and a concave surface on the other side.

In the acceleration sensor having such a distorted shape, the sensitivity to the acceleration has a directional property, and a situation such as erroneously detecting the acceleration in the direction in which the acceleration is not applied occurs. Bring

This detailed state is shown in FIGS. 11 (a) to 11 (c).
Shown in In FIG. 11A, 101 indicates an Al deposition film on the silicon substrate 1, and in such a laminated structure of the silicon substrate 1 and the Al deposition film 101,
Since the Al film 101 gives a compressive stress to the silicon substrate 1, the silicon substrate 1 warps so that the surface of the Al deposition film 101 becomes concave.

On the other hand, in the case of the SiO ₂ and ZnO films which give tensile stress to the silicon substrate 1, FIG.
As shown in (b) and (c), the SiO ₂ film 102, Zn
The O film 103 is warped so that the surface thereof becomes a convex surface.

However, there is a point that the stress transmitted to the silicon substrate 1 is minimized by adjusting the film thickness by combining the tensile and compressive stresses of these deposition films into a laminated structure.

Therefore, by forming the acceleration sensor using the film thickness that minimizes the stress on the substrate 1, the acceleration sensor can be formed without applying stress to the silicon substrate 1, that is, in the state where the silicon substrate 1 is not distorted. Can be formed.

Further, if the influence of the stress generated by the wiring portion is taken into consideration, the stress is not applied by adjusting the film thickness of each of the formed films, and the wiring pattern may be provided with a symmetrical shape. Good.

In this case, for example, as shown in FIG. 12, the input signal lines 128 may be arranged symmetrically with respect to the plane AA 'to make the wiring pattern more symmetrical.

According to the structure of the present embodiment as described above, even if the wiring pattern has an asymmetrical shape, by combining the wiring material with a material having a different stress direction applied to the silicon substrate, the acceleration sensor can be moved to detect the acceleration. The portion to be deformed can be symmetrically deformed, and more accurate acceleration can be detected.

It goes without saying that an acceleration sensor can be constructed by arbitrarily combining the configurations of the above-described embodiments.

Further, it is preferable to use a single crystal silicon substrate as the substrate in terms of device fabrication and characteristics.

[0184]

According to the present invention, it is possible to realize an acceleration sensor which is easy to form using a silicon LSI forming process and which is small and has high sensitivity.

Specifically, first, even when stress is applied to the support beam due to thermal history during the acceleration sensor formation process, twisting does not occur in the support beam. Accurate acceleration can be detected without a signal.

Alternatively, the parasitic capacitance is not generated between the common signal line on the excitation side or the reception side and the substrate, and the output signal is not attenuated, and the accurate acceleration can be detected.

Even when the output signal is reduced due to the miniaturization of the signal detection area accompanying the miniaturization of the sensor, the noise component becomes large with respect to the output signal,
Accurate acceleration can be detected without the output signal being attenuated by the capacitance between the parasitic wirings and the output signal not being accurately transmitted.

Alternatively, if the wiring material has poor coverage or if the wiring material crosses over a high step when a wiring having a small film thickness is used, the wiring on the step may be cut off and a wiring failure may occur. Moreover, the area of the wiring can be reduced on the flat region, the parasitic capacitance of the wiring can be reduced, the reliability is high, and accurate acceleration can be detected.

Alternatively, it is possible to prevent the resonator from thermally expanding due to a change in the ambient temperature to cause a change in the tension of the resonator, which causes a change in the resonance frequency to cause an error in acceleration measurement. It becomes possible to detect accurate acceleration.

Alternatively, even when different wiring pattern constituent materials are used, the stress applied to the support beams can be canceled by the thermal history during the acceleration sensor forming process, and the support beams are twisted. Since the output signal does not have a directionality with respect to the acceleration, it is possible to detect the accurate acceleration.

Even if a semiconductor process is used, it is possible to collectively form regions having different film thicknesses of the support beam and the propagating portion with good controllability by the impurity concentration of the impurity diffusion layer without depending on the etching rate. It becomes possible, and the obtained acceleration sensor can detect an accurate acceleration.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an acceleration sensor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the acceleration sensor.

FIG. 3 is an explanatory diagram of a manufacturing process of the acceleration sensor.

FIG. 4 is an explanatory diagram of the capacitance of the acceleration sensor according to the second embodiment of the present invention.

FIG. 5 is an equivalent circuit diagram of the capacitance of the acceleration sensor.

FIG. 6 is a partial configuration diagram of a wiring pattern of an acceleration sensor according to a third embodiment of the present invention.

FIG. 7 is a block configuration diagram of an acceleration sensor according to a fourth embodiment of the present invention.

FIG. 8 is a configuration diagram of a temperature compensation sensor of the acceleration sensor.

FIG. 9 is an explanatory diagram of wiring of the acceleration sensor according to the fifth embodiment of the present invention.

FIG. 10 is a configuration diagram of the acceleration sensor.

FIG. 11 is an explanatory diagram of a configuration for canceling the deformation of the wiring of the acceleration sensor.

FIG. 12 is a configuration diagram of the acceleration sensor.

FIG. 13 is a configuration diagram of a conventional resonance type acceleration sensor.

[Explanation of symbols]

1 Silicon Substrate 2 Inertial Body 3 Support Beam 4 Excitation Section 5 Reception Section 6 Propagation Section 7 Resonator 8 Input Signal Line 9 Input Side Common Signal Line 10 Output Signal Line 11 Output Side Common Signal Line 12 Excitation Side Piezoelectric Vibrator 13 Reception Side Piezoelectric vibrator 14 Resonator through hole 15 Inertial through hole 16 Interlayer insulating film 17 Protective film 32 Silicon nitride film 33 Silicon nitride film mask 34 Boron-containing diffusing agent 35 Boron impurity diffusion layer 36 Silicon nitride film mask 37 Boron-containing diffusing agent 38 Backside etching mask 41 Natural oxide film 71 Acceleration sensor 72 Temperature compensation sensor 73 Computing device 81 Silicon substrate 84 Excitation unit 85 Reception unit 86 Propagation unit 87 Resonator 88 Input signal line 89 Input side common signal line 90 Output signal line 91 Output side Common signal line 92 Excitation side piezoelectric vibrator 93 Reception side piezoelectric vibrator 94 Resonator Through hole 96 Interlayer insulating film 97 Protective film 98 Impurity diffusion layer 99 Input / output side common signal line 101 Al deposition film 102 SiO ₂ deposition film 103 ZnO deposition film 128 Input signal line 200 Vibratory body 201 Inertial body 202 Excitation section 203 Reception section 204 Propagation unit 205 Support beam

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Iwasawa 3-10-1 Higashisanda, Tama-ku, Kawasaki City, Kanagawa Matsushita Giken Co., Ltd. Matsushita Giken Co., Ltd., 10-10-1 (72) Inventor Takeo Sato 3-101-1 Higashisanda, Tama-ku, Kawasaki City, Kanagawa Prefecture Matsushita Giken Co., Ltd.

Claims (11)

[Claims] 1. An inertial body that is movable by acceleration, a support beam that supports the inertial body and is deformed when the inertial body moves, and an excitation unit and a piezoelectric element that are provided adjacent to the support beam and that include a piezoelectric element. A resonator having a receiving part and a propagating part, and when an acceleration is applied, a change in the vibration state of the resonator caused by the deformation of the resonator corresponding to the deformation of the support beam is input to the excitation part. An acceleration sensor for detecting an applied acceleration by detecting a signal and an output signal from a receiving unit, wherein a wiring pattern for connecting to the supporting beam and the resonance unit formed in the vicinity thereof has a symmetrical shape. Accelerometer. 2. The acceleration sensor according to claim 1, wherein the acceleration sensor is formed using a single substrate, and the wiring pattern has a symmetrical shape on the substrate. 3. An inertial body that is movable by acceleration, a support beam that supports the inertial body and is deformed when the inertial body moves, and an excitation unit including a piezoelectric element that is installed adjacent to the support beam, and a piezoelectric element. A resonator having a receiving part and a propagating part, and when an acceleration is applied, a change in the vibration state of the resonator caused by the deformation of the resonator corresponding to the deformation of the support beam is input to the excitation part. An acceleration sensor that measures an applied acceleration by detecting a signal and an output signal from a receiving unit, wherein the substrate is made of silicon, and an impurity diffused between the wiring pattern communicating with the resonance unit and the substrate. Accelerometer with area. 4. The acceleration sensor according to claim 3, wherein the impurity diffusion region functions as a zero potential side signal line. 5. An inertial body that is movable by acceleration, a support beam that supports the inertial body and is deformed when the inertial body moves, and an excitation unit and a piezoelectric element that are provided adjacent to the support beam and that include a piezoelectric element. A resonator having a receiving part and a propagating part, and when an acceleration is applied, a change in the vibration state of the resonator caused by the deformation of the resonator corresponding to the deformation of the support beam is input to the excitation part. An acceleration sensor that measures an applied acceleration by detecting a signal and an output signal from a receiving unit, wherein the piezoelectric element is included in a capacitance between a pair of wiring patterns connected to the piezoelectric element of the receiving unit. An acceleration sensor in which the electrostatic capacitance due to the interlayer insulating film other than the region corresponding to is less than 1/10 of the electrostatic capacitance due to the interlayer insulating film in the region corresponding to the piezoelectric element. 6. An inertial body that is movable by acceleration, a support beam that supports the inertial body and is deformed when the inertial body moves, and an excitation unit and a piezoelectric element that are provided adjacent to the support beam and that include a piezoelectric element. A resonator having a receiving part and a propagating part, and when an acceleration is applied, a change in the vibration state of the resonator caused by the deformation of the resonator corresponding to the deformation of the support beam is input to the excitation part. A signal and an output signal from the receiving unit, which is an acceleration sensor that measures the applied acceleration, of the wiring pattern that communicates with the resonance unit,
The wiring pattern of a portion that passes through the step formed by the piezoelectric element is wider than the wiring pattern on the flat area. 7. An inertial body that is movable by acceleration, a support beam that supports the inertial body and is deformed when the inertial body moves, and an excitation unit and a piezoelectric element that are provided adjacent to the support beam and that include a piezoelectric element. A resonator having a receiving part and a propagating part, and when an acceleration is applied, a change in the vibration state of the resonator caused by the deformation of the resonator corresponding to the deformation of the support beam is input to the excitation part. An acceleration sensor that measures the applied acceleration by detecting the signal and the output signal from the receiving unit, and further outputs an output signal that corresponds to environmental changes but does not correspond to acceleration changes. Acceleration sensor having. 8. A resonance sensor having a temperature compensating sensor, which has a support beam that is deformed when the temperature changes, an exciting unit made of a piezoelectric element, a receiving unit made of the piezoelectric element, and a propagating unit that are installed adjacent to the support beam. When the temperature changes, a change in the vibration state of the resonator caused by the deformation of the resonator corresponding to the deformation of the support beam is detected by the input signal to the excitation unit and the output signal from the reception unit. The acceleration sensor according to claim 7, which measures a temperature change. 9. An inertial body that is movable by acceleration, a support beam that supports the inertial body and is deformed when the inertial body moves, and an excitation unit including a piezoelectric element that is installed adjacent to the support beam, and a piezoelectric element. A resonator having a receiving part and a propagating part, and when an acceleration is applied, a change in the vibration state of the resonator caused by the deformation of the resonator corresponding to the deformation of the support beam is input to the excitation part. An acceleration sensor that measures an applied acceleration by detecting a signal and an output signal from a reception unit, wherein a wiring pattern that communicates with the resonance unit applies a force that deforms the support beam in a first direction. And an element that applies a force that deforms in a direction opposite to the first direction. 10. The acceleration sensor according to claim 1, wherein the propagating portion and the inertial body are formed by utilizing an impurity diffusion region formed on the substrate. 11. The formation of an acceleration sensor according to claim 10, wherein the support beam and the propagation portion having different thicknesses are formed by an etching process using different diffusion depths of impurity diffusion regions in the silicon substrate as stop layers. Method.