JP2822598B2 - Vibration type transducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention does not adhere to the vacuum chamber wall even when the vibrating beam may come into contact with the wall of the vacuum chamber due to disturbance such as impact or buckling. The present invention relates to a vibratory transducer that completely returns to its original state when disturbance is removed.

<Prior Art> FIG. 4 is an explanatory view of a main part of a conventional example generally used in the prior art.
No. 62-166176, entitled "Method of Manufacturing Vibrating Transducer", filed on July 2, 1987.

 FIG. 5 is a sectional view taken along line AA of FIG.

In the figure, 1 is a semiconductor single crystal substrate, and 2 is a measurement diaphragm provided on the semiconductor substrate 1 and receiving a measurement pressure Pm.

Reference numeral 3 denotes a strain detection sensor embedded in the measurement diaphragm 2, and the vibrating beam 3 is used.

Reference numeral 4 denotes a shell made of a semiconductor epitaxial growth layer for sealing, and seals the vibrating beam 3 with the measurement diaphragm 2.

Vibrating beam 3 and measuring diaphragm 2 around vibrating beam 3
A vacuum chamber 5 is provided between the vacuum chamber 5 and the shell 4.

The vibrating beam 3 includes a magnetic field generated by a permanent magnet (not shown) and a closed-loop self-excited oscillation circuit (not shown) connected to the vibrating beam 3.
Thus, the vibrating beam 3 is oscillated by natural vibration.

In the above configuration, the measurement pressure is applied to the measurement diaphragm 2.
When Pm is applied, the axial force of the vibrating beam 3 changes, and the natural frequency changes. Therefore, the measurement pressure Pm can be measured by changing the oscillation frequency.

FIG. 6 is an example of a manufacturing explanatory view of the conventional example shown in FIG. 5, which is filed by the applicant of the present invention and filed with Japanese Patent Application No. 63-86946, entitled "Method of Manufacturing Vibrating Transducer", Apr. Month 8
This is an improved version of Japanese Patent Application.

 Hereinafter, FIG. 6 will be described.

(1) As shown in FIG. 6A, n-type silicon (10
A film 101 of silicon oxide or silicon nitride is formed on the substrate 1 cut in the 0) plane. A required portion 102 of the film 101 is removed by photolithography.

(2) As shown in FIG. 6 (B), hydrogen (H ₂ ) at 1050 ° C.
Etching is performed with hydrogen chloride in an atmosphere to etch a required portion 102 of the substrate 1 and undercut the film 101 to form a concave portion 103.

Instead of hydrogen chloride, high-temperature steam or oxygen may be used, or anisotropic etching with an alkaline solution at 40 ° C. to 130 ° C. may be used.

(3) As shown in FIG. 6 (C), hydrogen (H ₂ ) at 1050 ° C.
In an atmosphere, a selective epitaxial growth method is performed by mixing hydrogen chloride gas into a source gas.

That is, the first epitaxial layer 104 corresponding to the lower half of the vacuum chamber 5 is selectively epitaxially grown using P-type silicon having a boron concentration of 10 ¹⁸ cm ⁻³ .

A second epitaxial layer 105 corresponding to the vibrating beam 3 is formed on the surface of the first epitaxial layer 104 with P-type silicon having a boron concentration of 3 × 10 ¹⁹ cm ⁻³ so as to cover a required portion 102.
Is selectively epitaxially grown.

A third epitaxial layer 106 corresponding to the upper half of the vacuum chamber 5 is selectively epitaxially grown on the surface of the second epitaxial layer 105 using P-type silicon having a boron concentration of 10 ¹⁸ cm ^-3 .

A fourth epitaxial layer 107 corresponding to the shell 4 is selectively epitaxially grown on the surface of the third epitaxial layer 106 by P-type silicon having a boron concentration of 3 × 10 ¹⁹ cm ⁻³ .

(4) As shown in FIG. 6 (D), the silicon oxide or silicon nitride film 101 is made of hydrofluoric acid (HF).
Then, etching is performed, and an etching injection port 108 is provided.

(5) As shown in FIG. 6 (E), a positive pulse or a positive voltage is applied to the substrate 1 with respect to the fourth layer, an alkaline solution is injected from the etching injection port 108, and the first epitaxial layer is formed. The 104 and the third epitaxial layer 106 are selectively etched and removed.

Second epitaxial layer 105 and first epitaxial layer 104
Alternatively, there is a difference in the etching action between the third epitaxial layer 106 and the third epitaxial layer 106 because the suppression action occurs in the etching action when the concentration of boron is 3 × 10 ¹⁹ cm ⁻³ or more.

(6) As shown in FIG. 6 (G), hydrogen (H ₂ ) at 1050 ° C.
N-type silicon is epitaxially grown in the substrate 1
Then, an epitaxial growth layer 111 is formed on the outer surface of the fourth epitaxial layer 107, and the etching injection port 108 is closed.

 In this step, the etching inlet 108 is closed by thermal oxidation.

Polysilicon is deposited at the position of the etching inlet 108 by the CVD method or the sputtering method, and the etching
Close 08.

The etching injection port 108 is filled by a silicon epitaxial method using a vacuum deposition method.

An insulating material, for example, glass (SiO ₂ ), nitride, alumina, or the like may be filled in the etching injection port 108 by a CVD method, a sputtering method, or a vapor deposition method.

<Problems to be solved by the invention> However, in such an apparatus, since the surface of the vibrating beam 3 is a mirror surface and has a small surface roughness and is active, the vibration beam 3 may be subjected to disturbance such as an impact or buckling due to a large compressive force. When the vibrating beam contacts the wall surface of the vacuum chamber, it may adhere to the wall surface of the vacuum chamber as it is.

As a countermeasure, it is conceivable that the side wall surface of the vacuum chamber on the substrate side is formed as an inclined surface, and that the side surface in the longitudinal direction of the vibrating beam is brought into contact with the inclined surface to make line contact.

However, even with this configuration, it is not possible to solve the problem that the vibrating beam adheres to the shell side wall surface of the vacuum chamber.

 The present invention solves this problem.

An object of the present invention is to prevent vibration beams from coming into contact with the wall surface of a vacuum chamber due to disturbance such as impact or buckling. To provide shape transducers.

<Means for Solving the Problems> In order to achieve this object, the present invention relates to a vibrating beam provided on a silicon substrate and surrounding the vibrating beam such that a gap is maintained around the vibrating beam. A vibration type transducer comprising: a shell made of a silicon material forming the substrate and a vacuum chamber; excitation means for exciting the vibrating beam; and excitation detecting means for detecting vibration of the vibrating beam. A vibrating transducer is provided, comprising a horn-shaped protrusion provided along a longitudinal side surface of the vibrating beam so as not to adhere to a wall surface of the vacuum chamber and to face a shell side wall surface of the vacuum chamber. It was done.

<Operation> In the above configuration, when the measured pressure of the vibrating beam is applied,
Since the axial force of the vibrating beam changes and the natural frequency changes, the measurement pressure can be measured by changing the oscillation frequency.

Since the vibrating beam is provided along the longitudinal side surface of the vibrating beam facing the shell side wall surface of the vacuum chamber so that the vibrating beam does not adhere to the wall surface of the vacuum chamber, the convex portion is provided. Even if the vibrating beam may come into contact with the shell wall due to disturbances such as shocks or buckling, the vibrating beam does not adhere to the shell wall due to the presence of the projection, and it is possible to completely return to the original state if the disturbance is removed I can do it.

 Hereinafter, a detailed description will be given based on embodiments.

<Embodiment> FIG. 1 is an explanatory diagram of a main part configuration of an embodiment of the present invention, and is an explanatory diagram in a case where it is used for pressure measurement.

In the figure, the same symbols as those in FIG. 5 indicate the same functions.

Reference numeral 2 denotes a measurement diaphragm provided on the semiconductor substrate 1 and receiving a measurement pressure Pm.

Reference numeral 3 denotes a strain detection sensor embedded in the measurement diaphragm 2, and the vibrating beam 3 is used.

Reference numeral 4 denotes a shell made of a semiconductor epitaxial growth layer for sealing, and seals the vibrating beam 3 with the measurement diaphragm 2.

Vibrating beam 3 and measuring diaphragm 2 around vibrating beam 3
A vacuum chamber 5 is provided between the vacuum chamber 5 and the shell 4.

Numeral 11 denotes a horn-shaped protrusion provided along the longitudinal side surface of the vibrating beam 3 so as to oppose the shell 4 side wall surface of the vacuum chamber 5 so that the vibrating beam 3 does not adhere to the wall surface of the vacuum chamber 5.

In the above configuration, when the measurement pressure is applied to the vibrating beam 3, the axial force of the vibrating beam 3 changes and the natural frequency changes, so that the measurement pressure can be measured by changing the oscillation frequency.

Thus, according to the present invention, even if the vibrating beam 3 comes into contact with the wall surface of the vacuum chamber 5 due to disturbance such as impact or buckling, the vibrating beam 3 If the disturbance is removed without adhering to the side wall surface of the shell 4, it can be completely restored.

Such an apparatus is made, for example, as shown in FIG.

(1) As shown in FIG. 2A, n-type silicon (10
A silicon oxide or silicon nitride film 201 is formed on the substrate 1 cut on the 0) plane. A required portion 202 of the film 201 is removed by photolithography.

(2) As shown in FIG. 2 (B), hydrogen (H ₂ ) at 1050 ° C.
Etching is performed with hydrogen chloride in an atmosphere to etch a required portion 202 of the substrate 1 and undercut the film 201 to form a concave portion 203.

Instead of hydrogen chloride, high-temperature steam or oxygen may be used, or anisotropic etching with an alkaline solution at 40 ° C. to 130 ° C. may be used.

(3) As shown in FIG. 2 (C), a selective epitaxial growth method is performed in a hydrogen (H ₂ ) atmosphere by mixing hydrogen chloride gas into a source gas.

That is, at a temperature of 1050 ° C., the first epitaxial layer 204 corresponding to the lower half of the vacuum chamber 5 is selectively epitaxially grown with P-type silicon having a boron concentration of 10 ¹⁸ cm ⁻³ .

At a temperature of 1050 ° C., the surface of the first epitaxial layer 204 is formed by P-type silicon having a boron concentration of 3 × 10 ¹⁹ cm ⁻³ .
The second portion corresponding to the vibrating beam 3 is closed so as to cover the required portion 202.
The epitaxial layer 205 is selectively epitaxially grown.

At a temperature of 950 ° C., the surface of the second epitaxial layer 205 is formed by P-type silicon having a boron concentration of 3 × 10 ¹⁹ cm ⁻³ .
The protrusion layer 2051 corresponding to the protrusion 11 is selectively epitaxially grown.

P-type silicon with boron concentration of 10 ¹⁸ cm ^-3 makes convex layer
On the surface of 2051, a third epitaxial layer 206 corresponding to the upper half of the vacuum chamber 5 is selectively epitaxially grown.

The fourth epitaxial layer 207 corresponding to the shell 4 is selectively epitaxially grown on the surface of the third epitaxial layer 206 using P-type silicon having a boron concentration of 3 × 10 ¹⁹ cm ⁻³ .

(4) As shown in FIG. 2D, the silicon oxide or silicon nitride film 201 is removed by etching with hydrofluoric acid (HF), and an etching injection port 208 is provided.

(5) As shown in FIG. 2 (E), a positive pulse or a positive voltage is applied to the substrate 1 with respect to the fourth layer, an alkaline solution is injected from the etching injection port 208, and the first epitaxial layer is formed. The 204 and the third epitaxial layer 206 are selectively etched and removed.

Second epitaxial layer 205 and first epitaxial layer 204
Alternatively, the reason why there is a difference in the etching action between the third epitaxial layer 206 and the third epitaxial layer 206 is that when the concentration of boron is 3 × 10 ¹⁹ cm ⁻³ or more, the etching action is suppressed.

The difference in the etching action between the second epitaxial growth layer 205 and the convex layer 2051 is due to the difference in the temperature conditions.

Thus, the convex layer 2051 has a convex shape because it has anisotropic etching characteristics.

(6) As shown in FIG. 2 (F), hydrogen (H ₂ ) at 1050 ° C.
N-type silicon is epitaxially grown in the substrate 1
Then, an epitaxial growth layer 209 is formed on the outer surface of the fourth epitaxial layer 207, and the etching injection port 208 is closed.

As a result, when the wall surface of the vacuum chamber 5 is a mirror surface, since the surface roughness is small and active, when the vibrating beam 3 comes into contact with the wall surface of the vacuum chamber 5 due to disturbance such as an impact or buckling due to a large compressive force, There is a possibility that the vibration beam 3 may adhere to the wall surface of the vacuum chamber 5 as it is, but the vibration beam 3 is opposed to the wall surface of the vacuum chamber 5 on the shell 4 side so that the vibration beam 3 does not adhere to the wall surface of the vacuum chamber 5.
Since the angular projections provided along the longitudinal side surfaces of the vacuum chamber 5 are provided, the vibration beam 3 does not adhere to the wall surface of the vacuum chamber 5 on the shell 4 side, and the reliability can be improved.

The method of manufacturing the device of the present invention is not limited to the above method.

FIG. 3 is an explanatory view of a main part configuration of a usage example of the vibrating beam of the present invention.

In the figure, reference numeral 3 denotes a vibrating beam. The vibrating beam 3 includes two first vibrators 31 fixed at both ends to the diaphragm 3 and arranged in parallel with each other, and a second vibrator mechanically coupling the antinodes of the vibration of the first vibrator 31 to each other. 32.

Reference numeral 40 denotes an input transformer 41 which applies a DC magnetic field orthogonal to the vibrating beam 3 by the magnet 30 and applies AC current to both ends of one of the first vibrators 31
And an exciting means for exciting the vibrating beam 3 in a direction orthogonal to the magnetic field and the current by the magnetic induction action.

The input transformer 41 has a secondary side connected to both ends of one of the first vibrators 31.

Reference numeral 50 denotes vibration detecting means for detecting an electromotive force generated at both ends of the other first vibrator 31. In this case, the output transformer
51 and an amplifier 52 are used. The primary side of the output transformer 51 is connected to both ends of the other first oscillator 31, the secondary side is connected to the output terminal 53 via the amplifier 52, and is branched and connected to the primary side of the input transformer 41. Thus, a positive feedback self-excited oscillation circuit is constituted as a whole. The vibration of the vibrating beam 3 is detected by the vibration detecting means 50 and taken out as an output signal.

<Effect of the Invention> As described above, the present invention relates to a vibrating beam provided on a silicon substrate, and surrounding the vibrating beam so that a gap is maintained around the vibrating beam, and forming the substrate and the vacuum chamber. A vibrating transducer, comprising: a shell made of a silicon material; exciting means for exciting the vibrating beam; and exciting detecting means for detecting vibration of the vibrating beam, wherein the vibrating beam adheres to a wall surface of the vacuum chamber. A vibratory transducer is provided which has a horn-like convex portion provided along the longitudinal side surface of the vibrating beam so as not to face the shell side wall surface of the vacuum chamber.

As a result, when the wall surface of the vacuum chamber is a mirror surface, the surface roughness is small and active, so when the vibrating beam comes into contact with the wall surface of the vacuum chamber due to disturbance such as impact or buckling due to large compression force,
There is a risk of sticking to the wall of the vacuum chamber as it is,
In order to prevent the vibrating beam from adhering to the wall surface of the vacuum chamber, an angular convex portion provided along the longitudinal side surface of the vibrating beam was provided opposite to the shell-side wall surface of the vacuum chamber. The reliability can be improved without adhering to the shell side wall surface of the vacuum chamber.

Therefore, according to the present invention, even if the vibrating beam may come into contact with the wall surface of the vacuum chamber due to disturbance such as an impact or buckling, it does not adhere to the wall surface of the vacuum chamber and completely returns to its original state if the disturbance is removed. Type transducer can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a main part of an embodiment of the present invention, FIG. 2 is an explanatory view of the production of FIG. 1, FIG. 3 is an explanatory view of a main part of an example of use of the apparatus of the present invention, FIG. FIG. 5 is an explanatory view of the structure of a conventional example generally used from the prior art, FIG. 5 is a sectional view taken along line AA of FIG. 4, and FIG. 6 is an explanatory view of the operation of FIG. 1 ... substrate, 2 ... measurement diaphragm, 3 ... vibrating beam,
4 shell, 5 vacuum chamber, 11 convex part, 30 magnet, 31 first oscillator, 32 second oscillator, 40 excitation means, 41 input transformer, 42 ... input terminal, 50 ... vibration detection means, 51 ... output transformer, 52 ... amplifier, 53 ...
... Output terminal, 201... Film, 202... 207: Fourth epitaxial layer, 208: Etching injection port, 209: Epitaxially grown layer.

Claims (1)

(57) [Claims] 1. A vibrating beam provided on a silicon substrate, a shell made of a silicon material surrounding the vibrating beam so as to maintain a gap around the vibrating beam and constituting a vacuum chamber with the substrate, In a vibratory transducer comprising: an exciting unit that excites a vibrating beam; and an excitation detecting unit that detects vibration of the vibrating beam, the shell side of the vacuum chamber so that the vibrating beam does not adhere to a wall surface of the vacuum chamber. A vibratory transducer, comprising: a rectangular convex portion provided along a longitudinal side surface of the vibrating beam facing a wall surface.