JP4586425B2 - Vibrating transducer - Google Patents

Description

  The present invention relates to a vibratory transducer in which a fine beam (vibrator) is formed in a fine vacuum chamber, and strain applied to the vibrator is measured with high accuracy.

Examples of vibration transducers that form a fine vibrator in a vacuum chamber and measure the strain applied to the vibrator with high accuracy include the following.
FIG. 26 is a side sectional view showing an example of a vibration type transducer that has been generally used. FIG. 27 is a cross-sectional view taken along the line AA. In the figure, reference numeral 1 denotes a semiconductor single crystal substrate, and 2 denotes a measurement diaphragm which is formed by thinly processing a part of the semiconductor substrate 1 and receives a measurement pressure Pm. Reference numeral 3 denotes a strain detection sensor provided so as to be embedded in the measurement diaphragm 2. Here, a vibrating beam (vibrator) is used. Reference numeral 4 denotes a shell for vacuum-sealing the vibrator 3 in the measurement diaphragm 2 (semiconductor substrate 1). Reference numeral 5 denotes a vacuum chamber formed by the shell 4.

The vibrator 3 and the shell 4 are formed by a semiconductor manufacturing process such as epitaxial growth or etching, and are processed into a desired shape.
The vibrator 3 is excited by a magnetic field generated by a permanent magnet (not shown) and a closed loop self-excited circuit (not shown) connected to the vibrator 3, and vibrates at its natural frequency (resonance frequency). Is configured to do.
Therefore, when the measurement pressure Pm is applied to the measurement diaphragm 2, the axial force of the vibrator 3 changes and the resonance frequency changes. By detecting this change in the resonance frequency (oscillation frequency), the measurement pressure Pm The size can be measured.

Polycrystalline silicon resonant beam converter and method for manufacturing the same Patent application title: Vibrating transducer and method for manufacturing the same Resonance gauge with microbeam driven by constant electric field 07-502274 Apparatus having force transducer and method for manufacturing the same

As described above, when a permanent magnet is used for exciting the vibrator 3, the vibrator 3 can be vibrated only by supplying a current to the vibrator 3, and by simply measuring the induced current, the resonance frequency can be reduced. Changes can be detected.
However, there are problems such as the need for a permanent magnet and the need to position the magnet and the vibrator with high precision, which increases the manufacturing cost.

  In the vibratory transducer configured as described above, in order to simplify the element manufacturing process or to form an electric element such as a piezoresistor in the lower part of the vibrator, polycrystalline silicon is formed in the vibrator portion. Although it is often used, in polycrystalline silicon, it is not easy to control the residual strain of the vibrator, and in order to suppress variations in resonance frequency, it is necessary to use special film formation conditions and strictly control this. There is.

  When the vibrator is made of single crystal silicon, the residual strain can be easily controlled. However, in order to form the vibrator, the film properties are controlled by epitaxial growth or impurity diffusion. Therefore, a structure in which a sacrificial layer under the vibrator is formed of an oxide film or an electric element such as a piezoresistor is formed in or under the vibrator becomes difficult.

  In a vibratory transducer, regardless of the constituent material of the vibrator, in order to increase the mechanical Q value of the vibrator, it is necessary to form the vibrator in a fine vacuum chamber, and MEMS (Micro Electro Mechanical Mechanical Systems) When a vibration transducer is realized by technology, its structure is naturally limited, and it is desirable that the driving method and detection method be as simple as possible.

An object of the present invention is to realize a vibratory transducer that can eliminate the drawbacks of the above-described conventional devices and simplify the mechanism for driving a vibrator and detecting a change in resonance frequency.
Further, according to the present invention, it is possible to easily control the residual strain of the vibrator by configuring the vibrator with single crystal silicon, and to simplify the driving mechanism of the vibrator and the detection mechanism of the resonance frequency. The object is to realize a vibration transducer that can be used.
Another object of the present invention is to realize a vibratory transducer capable of removing a noise component such as a current flowing through a parasitic capacitance and obtaining a detection output with an improved S / N ratio.

  In order to achieve such an object, the vibratory transducer of the present invention has the following configuration.

(1) A vibrator is formed in a semiconductor substrate, and the vibrator is arranged in a vacuum chamber formed by a shell, and the magnitude of strain applied to the vibrator is detected as a change in the resonance frequency of the vibrator. In the vibratory transducer, the first vibrator unit having the first vibrator formed inside the shell and the second vibrator are formed, and the second vibrator is formed by etching. The first vibration except that a part of the sacrificial layer in contact with the second vibrator is left when the second vibrator has a resonance frequency different from that of the first vibrator. A second vibrator unit having the same configuration as that of the child unit, and detecting a change in resonance frequency due to strain as a change in capacitance between the vibrator and the shell. 2 vibrator units The Tsu bets excited at a resonant frequency in said first oscillator, and detects a difference in current flowing through each of the electrostatic capacitance in the first and second transducer units.

(2) A vibrator is formed in a semiconductor substrate, and the vibrator is arranged in a vacuum chamber formed by a shell so that the magnitude of strain applied to the vibrator is detected as a change in the resonance frequency of the vibrator. In the vibratory transducer, the first vibrator unit having the first vibrator formed inside the shell and the first vibrator having a different length from the first vibrator. And a second vibrator unit having the same configuration as the first vibrator unit except that the second vibrator unit has a resonance frequency different from that of the first vibrator unit. Detecting the change in capacitance between the child and the shell, and exciting the first and second vibrator units at a resonance frequency of the first vibrator, so that the first and second vibrators are excited. Uni And detecting a difference between the currents flowing through the electrostatic capacitance in and.
(3) A vibrator is formed in a semiconductor substrate, and the vibrator is arranged in a vacuum chamber formed by a shell so that the magnitude of strain applied to the vibrator is detected as a change in the resonance frequency of the vibrator. The vibration type transducer includes a first vibrator unit having a first vibrator formed inside the shell, and a second vibrator having a resonance frequency different from that of the first vibrator. And a second vibrator unit having the same configuration as the first vibrator unit, and detecting a change in resonance frequency due to strain as a change in capacitance between the vibrator and the shell. In addition, the first and second vibrator units are excited at a resonance frequency in the first vibrator, and a difference between currents flowing through the respective capacitances in the first and second vibrator units is determined. Out,
The second vibrator unit has an arrangement of the first vibrator unit and an etchant introduction hole for forming the second vibrator, and an etchant introduction hole for forming the first vibrator. In this arrangement, the pattern is formed by the same process except for the patterning process so that the position corresponding to the central portion of the vibrator is omitted .
(4) The vibration transducer according to any one of (1) to (3), wherein the semiconductor substrate is a silicon single crystal substrate.

(5) In the second of the transducer unit, wherein the second oscillator when forming by etching, to leave the sacrificial layer, characterized in (1) in contact with the upper surface of the second oscillator Vibratory transducer.
(6) said second oscillator unit, wherein the second oscillator when forming by etching, in (1) to leave the sacrificial layer in contact with the lower surface of the second oscillator Vibratory transducer.
(7) In the second of the transducer unit, when the second vibrator is formed by etching, to leave the sacrificial layer, characterized in (1) in contact with the upper and lower surfaces to the second oscillator The vibratory transducer as described.

( 8 ) The vibratory transducer according to any one of (1) to (7) , wherein the first vibrator unit and the second vibrator unit are formed in the same vacuum chamber.
( 9 ) The vibratory transducer according to any one of (1) to ( 8 ), wherein the first vibrator unit and the second vibrator unit are formed on the same substrate.
( 10 ) The first and second vibrator units are characterized in that a silicon oxide film and a silicon nitride film are used as sacrificial layers to be etched when etching is performed between the vibrator and the shell. (1) The vibrating transducer according to any one of (4), (5), (6), (7), (8), and (9) .

( 11 ) In the first and second vibrator units, the vibrator and the sacrificial layer under the vibrator are formed by impurity diffusion into the silicon single crystal substrate. (1) , (4) , (5), (6), (7), (8), (9), (10) .
( 12 ) In the first and second vibrator units, the sacrificial layer under the vibrator is formed by impurity diffusion into the substrate of the silicon single crystal, and the vibrator is formed by patterning epitaxial growth on the substrate. The vibratory transducer according to any one of (1) , (4), (5), (6), (7), (8), (9), and (10) .
( 13 ) In the first and second vibrator units, the sacrificial layer under the vibrator and the vibrator is formed by patterning epitaxial growth of the silicon single crystal on the substrate (1) , ( 1) 4) The vibrating transducer according to any one of (5), (6), (7), (8), (9), and (10) .

As described above, in the vibratory transducer according to the present invention, when forming the vacuum chamber surrounding the vibrator, the silicon oxide film and the silicon nitride film are used as the sacrificial layer on the top of the vibrator, so that a very narrow gap is etched. It is possible to drive the vibrator and detect a change in the resonance frequency using the capacitance between the vibrator and the shell.
Further, the first and second vibrator units having different resonance frequencies are formed by the same process, and the difference between the currents flowing through the respective capacitances in the first and second vibrator units is detected. Therefore, it is possible to obtain a detection output with an improved S / N ratio by removing noise components such as a current flowing through the parasitic capacitance.

  Hereinafter, the vibratory transducer of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an embodiment of the vibration type transducer of the present invention. In the figure, (a) is a cross-sectional view showing a first vibrator unit U1 having a first vibrator 31, and (b) a second vibrator unit U2 having a second vibrator 32. 23 and 24 are denoted by the same reference numerals. Reference numeral 16 denotes a sacrificial layer left in a part of the second vibrator 32. As shown in the figure, the first vibrator unit U1 and the second vibrator unit U2 are formed by the same process and have the same configuration. The only difference is that the sacrificial layer 16 is left in a part of the second vibrator 32.

Therefore, the first vibrator 31 and the second vibrator 32 have different resonance frequencies, but have the same electrostatic capacitance with the shell 4 and peripheral parasitic capacitance.
In the vibratory transducer of the present invention, the drive and resonance frequencies of the first and second vibrators 31 and 32 are made using the capacitance between the first and second vibrators 31 and 32 and the shell 4. In addition to detecting the change, the first and second vibrator units U1 and U2 are configured to detect a difference in current flowing through each capacitance, so that noise components such as current flowing through the parasitic capacitance can be detected. The detection output with improved S / N ratio can be obtained.

  2 to 10 are process diagrams showing an outline of the manufacturing process in the first vibrator unit U1. The manufacturing process will be described below with reference to the drawings.

In FIG. 2, a silicon oxide film 10a is formed on an N-type silicon single crystal substrate 1 and patterned.
A portion from which the oxide film has been removed is undercut to form a recess, and selective epitaxial growth is performed using P-type silicon having a boron concentration of 10 ¹⁸ cm ⁻³ to grow P ⁺ single crystal silicon 11. Next, a P ⁺⁺ single crystal silicon 12a is grown on the surface of the P ⁺ single crystal silicon 11 with a boron concentration of 3 × 10 ¹⁹ cm ⁻³ by closing the recess and further upward. Later, the P ⁺ single crystal silicon layer becomes the gap under the vibrator, and the P ⁺⁺ single crystal silicon layer becomes the vibrator.

In FIG. 3, a silicon oxide film 10b is formed on the surface of the substrate including on the P ⁺⁺ single crystal silicon 12a and patterned. The portion indicated by the recess D from which the oxide film has been removed becomes a grounding portion to the substrate in the shell.

In FIG. 4, a silicon nitride film 13 is formed on the substrate surface including the recess D and patterned. The silicon oxide film 10b and the silicon nitride film 13 on the P ⁺⁺ single crystal silicon 12a (vibrator) form a gap on the vibrator. The size of the capacitance formed in each part is determined by the film thickness and the area of the vibrator. Therefore, by controlling these values, the capacitance for driving and detecting the vibrator can be optimized.

In FIG. 5, P ⁺⁺ polysilicon 14 is formed on the entire surface, and an etching solution introduction hole E for sacrificial layer etching is formed by patterning. This P ⁺⁺ polysilicon 14 will later become a wiring for taking out the shell and electrodes. The wiring can also be formed by using P ⁺⁺ / P ⁺ single crystal silicon or by diffusing impurities into the silicon substrate before selective epitaxial growth. It is preferable to select the parasitic capacitance between the wiring and the silicon substrate to be the smallest.

  In FIG. 6, hydrofluoric acid is introduced from the etching solution introduction hole E to remove the silicon nitride film 13 and the silicon oxide film 10b. Since the etching rate of the silicon nitride film 13 is slow at the grounding portion of the shell to the substrate, the silicon nitride film 13 becomes an etching stop layer in the lateral direction.

In FIG. 7, P ⁺ single crystal silicon 11 is removed with an alkaline solution (hydrazine, KOH, TMAH, etc.). At this time, the P ⁺⁺ single crystal silicon 12a and the P ⁺⁺ polysilicon 14 are not etched because impurities are introduced at a high concentration. Further, by applying a voltage of 1 to 2 V to the N-type silicon substrate during etching with an alkaline solution, it can be protected from being etched. The length direction of the vibrator is set as an etching stop by utilizing the slow etching rate in the <111> direction of the silicon single crystal.

In FIG. 8, a sealing member 15 (for example, SiO ₂ formed by sputtering, glass, etc.) is formed by sputtering, vapor deposition, CVD, epitaxial growth, etc. Form.

In FIG. 9, P ⁺⁺ polysilicon 14 is patterned to form a shell and electrical wiring from the shell, and an electrode for a bonding pad.
In FIG. 10, the silicon substrate 1 is thinned from the back surface, and the measurement diaphragm 2 is formed.
In this way, the first vibrator 31 and the first vibrator unit U1 having this vibrator are formed.

Next, a manufacturing process of the second vibrator 32 and the second vibrator unit U2 having the vibrator will be described.
11 to 15 are process diagrams showing an outline of the manufacturing process in the second vibrator unit U2. Note that the manufacturing process in the second vibrator unit U2 is basically the same as the manufacturing process in the first vibrator unit U1 described above, and only the differences will be described here.

  FIG. 11 is a view corresponding to FIG. 5 and showing an example of arrangement of the etching solution introduction hole E. FIG. In the figure, the arrangement of the etching solution introduction holes E is viewed from above. For example, the introduction holes at positions corresponding to the central portion of the vibrator are omitted, and the intervals between these portions are widened. In the case of the first vibrator unit U1, the etchant introduction holes E are provided at equal intervals.

  Therefore, by controlling the etching time, a part of the sacrificial layer 16 can be left as shown in FIG. FIG. 13 shows this state corresponding to FIG. A part of the sacrificial layer 16 corresponding to the position where the interval between the etching solution introduction holes E is widened remains without being etched.

FIG. 14 is a process corresponding to FIG. 7, and the P ⁺ single crystal silicon 11 under the vibrator is removed with an alkaline solution (hydrazine, KOH, TMAH, etc.). Here, all of the P ⁺ single crystal silicon 11 under the vibrator is removed.
FIG. 15 shows this state corresponding to FIG. A part of the sacrificial layer 16 on the vibrator remains.

  As described above, when the arrangement of the etching solution introduction hole E is changed and the etching time is controlled, a part of the sacrificial layer 16 in contact with the vibrator can be left, and the first vibrator 31 has a different resonance frequency. Two vibrators 32 can be formed.

In FIG. 16, P ⁺⁺ polysilicon (14) is patterned so as to be connected to the first and second vibrators 31 and 32, thereby forming the electrical wiring 20 and forming the electrode (bonding pad) 21. It is a top view which shows the state which carried out. The figure illustrates the case where the first and second vibrator units U1, U2 are formed on the same substrate.
Moreover, FIG. 17 is the BB sectional drawing.

  FIG. 18 shows an example of a drive and detection circuit for a vibrator, and shows a circuit portion for one vibrator. In the figure, Vb is a bias voltage (constant voltage), Vi is a drive voltage (AC), R1 and R2 are wiring resistances, R3 is a substrate resistance, OP1 is an operational amplifier, and R4 is an operational resistance. In such a configuration, C1 is a capacitance between the vibrator and the shell, and is a capacitance to be detected. C2 is a parasitic capacitance, and C3 and C4 are capacitances between the wiring and the substrate.

  When the capacitance C1 is constant and the angular frequency of Vi is ω, the amplitude of the output current is proportional to (C1 + C2) · Vi · ω. On the other hand, when C1 resonates at an angular frequency ω, assuming that the change in C1 due to resonance is ΔC1, a current having an amplitude proportional to ΔC1 · Vb · ω is approximately added. The resonance frequency is detected from the increase in current.

That is, in this circuit, it is possible to detect a change in C1 corresponding to a change in the resonance frequency as a change in the current flowing through R4.
However, in such a circuit, even if C1 does not change, the current flowing through C1, the current flowing through C2, and the current flowing through C3 and C4 are simultaneously detected, and this is a noise current.

  FIG. 19 is a block diagram showing an embodiment of a detection circuit used in the vibration type transducer of the present invention. In the figure, the same components as those in FIG. 18 are denoted by the same reference numerals. If the circuit of FIG. 18 is a detection circuit portion for the first transducer unit U1, the circuit including C12 and C22 is a detection circuit portion for the second transducer unit U2. That is, C12 is a capacitance between the second vibrator 32 and the shell 4, and C22 is its parasitic capacitance. The operational amplifier OP1 is configured to obtain a difference between currents flowing through the capacitor C1 of the first transducer unit U1 and the capacitor C2 of the second transducer unit U2. Further, the angular frequency ω of Vi is selected as the resonance frequency of the first vibrator 31.

  Therefore, if the first and second vibrator units U1 and U2 have exactly the same shape (C1 = C12, C2 = C22), the noise current flowing through the first vibrator unit U1 is converted into the second vibration by C1. Only the current Is that cancels with the noise current flowing in the child unit U2 and flows according to the change in the capacitance of C1 can be detected as Vo = Is × R4.

  Here, as described above, in the second vibrator unit U2, since a part of the sacrificial layer in contact with the second vibrator 32 is left and the resonance frequency is changed, C1, C12, and C2 Although C22 has a slightly different value, if the values of C1 and C12 are made larger than this difference, this effect can be reduced and a sufficient noise current removal effect can be obtained.

  In the first embodiment, as means for making the resonance frequencies of the first and second vibrators 31 and 32 different, a part of the sacrificial layer in contact with the second vibrator 32, particularly a sacrificial layer on the vibrator. However, the sacrificial layer to be left in the etching process is not limited to this, and may be a sacrificial layer under the vibrator or a sacrificial layer above and below the vibrator.

  As a means for making the resonance frequencies of the first and second vibrators 31 and 32 different, a method of changing the lengths of the first and second vibrators 31 and 32 is also possible.

  As a means for making the resonance frequencies of the first and second vibrators 31 and 32 different, a method in which the shell 4 of the second vibrator unit U2 is not vacuum-sealed is also possible. By not performing vacuum sealing, the vibration resistance of the vibrator 32 increases and the resonance frequency changes.

In the first embodiment, as shown in FIG. 16, the first and second vibrator units U1 and U2 are formed on the same substrate. However, the first and second vibrators are further illustrated. 31 and 32 can also be formed in the same vacuum chamber.
FIG. 20 is a plan view showing this state. As shown in the figure, the first and second vibrators 31 and 32 are formed in a common shell 4 (vacuum chamber).

FIG. 21 is a view corresponding to FIG. 11 and showing an arrangement example of the etching solution introduction holes E1 to E3. In the etching solution introduction hole E3 on the second vibrator 32 side, the introduction hole at a position corresponding to the central portion of the vibrator is omitted, and the interval between the portions is wide.
Therefore, by controlling the etching time, only a part of the sacrificial layer 16 on the second vibrator 32 side can be left.

  FIG. 22 is a cross-sectional view taken along the line AA corresponding to FIG. As shown in the figure, the first and second vibrators 31 and 32 are provided in the same vacuum chamber 5, and a part of the sacrificial layer 16 in contact with the second vibrator 32 is left.

  As described above, when the first and second vibrators 31 and 32 are formed in the same vacuum chamber, the sacrificial layer under the vibrator can be etched with a high yield in the process of forming the vibrator. .

  Even when the first and second vibrators 31 and 32 are formed in the same vacuum chamber, a method of changing the length of the vibrator can be used as means for changing the resonance frequency of the vibrator. .

  Further, in the first embodiment, the case where the first and second vibrator units U1 and U2 are formed on the same substrate is exemplified, but the first and second vibrator units U1 and U2 are As long as they are formed by the same process, they are not necessarily formed on the same substrate.

FIG. 23 is a block diagram showing another embodiment of the vibration type transducer of the present invention. In the example shown in the figure, in the step of forming a single crystal silicon layer serving as a vibrator on a part of the N-type silicon single crystal substrate 1, first, a P ⁺ diffusion layer 11a serving as a sacrificial layer under the vibrator is formed. Next, a P ⁺⁺ diffusion layer 12b to be a vibrator is formed.

FIG. 24 is a block diagram showing another embodiment of the vibration type transducer of the present invention. In the example shown in the figure, in the step of forming a single crystal silicon layer serving as a vibrator on a part of the N-type silicon single crystal substrate 1, first, a P ⁺ epitaxial layer 11b serving as a sacrificial layer under the vibrator is grown. Next, a P ⁺⁺ epitaxial layer 12c to be a vibrator is grown. P ⁺ epitaxial layer 11b and the ^{P ++} epitaxial layer 12c are sequentially patterned and formed into the desired shape.

FIG. 25 is a block diagram showing another embodiment of the vibration type transducer of the present invention. In the example shown in the figure, in the step of forming a single crystal silicon layer serving as a vibrator on a part of the N-type silicon single crystal substrate 1, first, a P ⁺ diffusion layer 11a serving as a sacrificial layer under the vibrator is formed. Next, a P ⁺⁺ epitaxial layer 12d serving as a vibrator is grown. The P ⁺⁺ epitaxial layer 12d is patterned and formed into a desired shape.

  In the above description, the case where single crystal silicon is used as the material for the substrate and the vibrator is exemplified, but the material for the substrate and the vibrator is not limited to this, and other semiconductor materials should be used. Is also possible.

The block diagram which shows one Example of the vibration type transducer of this invention. The manufacturing process figure of the vibration type transducer of this invention. The manufacturing process figure of the vibration type transducer of this invention. The manufacturing process figure of the vibration type transducer of this invention. The manufacturing process figure of the vibration type transducer of this invention. The manufacturing process figure of the vibration type transducer of this invention. The manufacturing process figure of the vibration type transducer of this invention. The manufacturing process figure of the vibration type transducer of this invention. The manufacturing process figure of the vibration type transducer of this invention. The manufacturing process figure of the vibration type transducer of this invention. The manufacturing process figure of the vibration type transducer of this invention. The manufacturing process figure of the vibration type transducer of this invention. The manufacturing process figure of the vibration type transducer of this invention. The manufacturing process figure of the vibration type transducer of this invention. The manufacturing process figure of the vibration type transducer of this invention. The top view which shows one Example of the vibration type transducer of this invention. BB sectional drawing of FIG. The block diagram which shows an example of the drive and detection circuit of a vibrator | oscillator. The block diagram which shows one Example of the detection circuit used for the vibration type transducer of this invention. The top view which shows the other Example of the vibration type transducer of this invention. FIG. 12 is a manufacturing process diagram corresponding to FIG. 11. AA sectional drawing equivalent to FIG. The block diagram which shows the other Example of the vibration type transducer of this invention. The block diagram which shows the other Example of the vibration type transducer of this invention. The block diagram which shows the other Example of the vibration type transducer of this invention. Side surface sectional drawing which shows an example of the vibration type transducer generally used conventionally. AA sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Measurement diaphragm 3 Vibrator 4 Shell 5 Vacuum chamber 10 Silicon oxide film 11 P + Single crystal silicon 12 P ++ Single crystal silicon 13 Silicon nitride film 14 P ++ Polysilicon 15 Sealing member 16 Sacrificial layer 20 Wiring 21 Bonding pad

Claims (13)

  A vibration that is formed in a semiconductor substrate and placed in a vacuum chamber formed by a shell so that the magnitude of strain applied to the vibrator is detected as a change in the resonance frequency of the vibrator. In the type transducer, when the first vibrator unit having the first vibrator formed inside the shell and the second vibrator are formed, and the second vibrator is formed by the etching process, The first vibrator unit is different from the first vibrator unit except that the second vibrator has a resonance frequency different from that of the first vibrator by leaving a part of the sacrificial layer in contact with the second vibrator. A second vibrator unit having the same configuration, and detecting a change in resonance frequency due to strain as a change in capacitance between the vibrator and the shell, and the first and second vibrations. Child unit It said first excited at the resonance frequency of the vibrator, the first and second vibratory transducers and detects the difference between the currents flowing through the electrostatic capacitance in the transducer unit.   A vibration that is formed in a semiconductor substrate and placed in a vacuum chamber formed by a shell so that the magnitude of strain applied to the vibrator is detected as a change in the resonance frequency of the vibrator. In the type transducer, the first vibrator unit having the first vibrator formed inside the shell and the first vibrator are formed to have a different length and different from the first vibrator. A second vibrator unit having the same configuration as that of the first vibrator unit except that the second vibrator has a resonance frequency, and changes the resonance frequency due to strain by the vibrator and the shell. And the first and second vibrator units are excited at a resonance frequency of the first vibrator, and the first and second vibrator units are excited by the first and second vibrator units. Vibratory transducers and detects a difference in current flowing through each of the electrostatic capacitance are. A vibration that is formed in a semiconductor substrate and placed in a vacuum chamber formed by a shell so that the magnitude of strain applied to the vibrator is detected as a change in the resonance frequency of the vibrator. In the type transducer, except that it has a first vibrator unit having a first vibrator formed inside the shell and a second vibrator having a resonance frequency different from that of the first vibrator. A second vibrator unit having the same configuration as the first vibrator unit, and detecting a change in resonance frequency due to strain as a change in capacitance between the vibrator and the shell; The first and second vibrator units are excited at a resonance frequency in the first vibrator, and a difference between currents flowing through the respective capacitances in the first and second vibrator units is detected.
The second vibrator unit has an arrangement of the first vibrator unit and an etchant introduction hole for forming the second vibrator, and an etchant introduction hole for forming the first vibrator. A vibratory transducer formed by the same process except for the patterning process so that the position corresponding to the central portion of the vibrator is omitted from the arrangement of the above .   The vibratory transducer according to claim 1, wherein the semiconductor substrate is a silicon single crystal substrate.   2. The vibration type according to claim 1, wherein a sacrificial layer in contact with the upper surface of the second vibrator is left when the second vibrator is formed by etching in the second vibrator unit. Transducer.   2. The vibration type according to claim 1, wherein a sacrificial layer in contact with a lower surface of the second vibrator is left when the second vibrator is formed by etching in the second vibrator unit. Transducer.   2. The vibration according to claim 1, wherein in the second vibrator unit, when the second vibrator is formed by etching, a sacrificial layer in contact with the upper and lower surfaces is left on the second vibrator. Type transducer.   The vibratory transducer according to any one of claims 1 to 7, wherein the first vibrator unit and the second vibrator unit are formed in the same vacuum chamber.   9. The vibratory transducer according to claim 1, wherein the first vibrator unit and the second vibrator unit are formed on the same substrate.   2. A silicon oxide film and a silicon nitride film are used as sacrificial layers to be etched when etching between the vibrator and the shell in the first and second vibrator units. The vibratory transducer according to any one of 4, 5, 6, 7, 8, and 9.   In the first and second vibrator units, the vibrator and the sacrificial layer under the vibrator are formed by impurity diffusion into the substrate of the silicon single crystal. The vibratory transducer according to any one of 7, 8, 9, and 10.   In the first and second vibrator units, the sacrificial layer under the vibrator is formed by impurity diffusion into the silicon single crystal substrate, and the vibrator is formed by patterning epitaxial growth on the substrate. The vibratory transducer according to any one of claims 1, 4, 5, 6, 7, 8, 9, and 10.   In the first and second vibrator units, the sacrificial layer under the vibrator and the vibrator is formed by patterning epitaxial growth on the substrate of the silicon single crystal, 1, 4, 5, 6, The vibratory transducer according to any one of 7, 8, 9, and 10.

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