JPH0419530A - Vibration type transducer - Google Patents

Abstract

PURPOSE:To easily adjust the tension or temperature coefficient of a vibration beam part by covering the surface of the vibration beam with the 1st layer of an oxide film and its surface with the 2nd layer of polysilicon, and adjusting the film thicknesses of both layers and adjusting the tension generated by the vibration beam and both layers. CONSTITUTION:When the vibration beam 3 is made of high-density boron silicon, about 100 - 300mu tension is obtained depending upon the boron density and when the 1st layer of the oxide film is formed, the compressive force is generated to vary the tension with the film thickness of the 1st layer, thereby adjusting the tension of the whole part of the vibration beam 3. Further, the 2nd layer of polysilicon whose tension is almost 0 provided on the external surface of the 1st layer to approximate the tension of the whole part of the vibration beam 3 to 0, so the tension can easily be adjusted on the whole. Consequently, the vibration transducer which can easily adjust the tension or temperature coefficient of the part of the vibration beam 3 is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a vibrating transducer in which the tension or temperature coefficient of a vibrating beam portion can be easily adjusted.

<Prior art> Fig. 8 is an explanatory diagram of the main part configuration of a conventional example that has been commonly used in the past.
No. 2-166176, entitled "Method for manufacturing a vibrating transducer," filed on July 2, 1988.

FIG. 9 is a sectional view taken along the line AA in FIG. 8.

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

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

Reference numeral 4 denotes a shell made of a semiconductor epitaxial growth layer for sealing, which seals the vibration beam 3 to the measurement diaphragm 2.

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

The vibrating beam 3 is configured to oscillate with the natural vibration of the vibrating beam 3 using a magnetic field generated by a permanent magnet (not shown) and a closed-loop automatic oscillation circuit (not shown) connected to the vibrating beam 3. .

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

FIG. 10 is an example of a manufacturing explanatory diagram of the conventional example shown in FIG. 8, and is filed by the applicant of the present application, Japanese Patent Application No. 86946/1983, title of the invention is "Method for manufacturing a vibrating transducer", 1988.
This is an improved version of the application filed on April 8th.

Below, FIG. 10 will be explained.

(1) As shown in Figure 10 (A), n-type silicon (1
A silicon oxide or silicon nitride film 101 is formed on a substrate 1 cut into a 00) plane. Required portions 102 of the film 101 are removed by photolithography.

(2) As shown in FIG. 10(B), etching is performed with hydrogen chloride in a hydrogen (H2) atmosphere at 1050° C. to etch required portions 102 on the substrate 1 to undercut the film 101 and create recesses. 103 is formed.

Note that instead of hydrogen chloride, high-temperature steam or oxygen may be used, or anisotropic etching may be performed using an alkaline solution at a temperature of 40 DEG C. to 130 DEG C.

(3) As shown in FIG. 10(C), selective epitaxial growth is performed in a hydrogen (H2) atmosphere at 1050° C. by mixing hydrogen chloride gas into the source gas.

That is, (1) the first epitaxial layer 104 corresponding to the lower half of the vacuum chamber 5 is made of P-type silicon with a boron concentration of 10 cm';
Select epitaxial growth.

(2) A second epitaxial layer 105 corresponding to the vibrating beam 3 is selectively epitaxially grown on the surface of the first epitaxial layer 104 using P-type silicon having a concentration of 3×10 cm − of poron so as to close the required portion 102 .

(2) 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 with a boron concentration of 10 cm'.

(2) A fourth epitaxial layer 107 corresponding to the shell 4 is selectively epitaxially grown on the surface of the third epitaxial layer 106 using P-type silicon with a boron concentration of 3×10” cm −3 .

(4) As shown in FIG. 10(D), silicon oxide,
Alternatively, the silicon nitride film 101 may be coated with hydrogen fluoride a (
HF) to remove the etching inlet 10.
8 will be provided.

(5) As shown in FIG. 10(E), a positive pulse or positive voltage is applied to the substrate 1 for the fourth layer, and alkaline solution is injected from the etching injection port 108 to form the first epitaxial layer. 104 and third epitaxial layer 106 are selectively etched and removed.

Second epitaxial layer 105 and first epitaxial layer 1
04 or the third epitaxial layer 106 is due to the boron concentration of 3×10"
This is because when it exceeds cm-3, the etching action is inhibited.

(6) As shown in FIG. 10(F), epitaxial growth of n-type silicon is performed in hydrogen (H2) at 1050° C. to form an epitaxial growth layer 111 on the outer surface of the substrate 1 and the fourth epitaxial layer 107, Close the etching inlet 108.

Note that this process is ■ Close the etching inlet 108 by thermal oxidation.

(2) Etching polysilicon at the location of the etching inlet 108 by CVD or sputtering, and closing the etching inlet 108;

(2) Filling the etching inlet 108 by silicon epitaxial method using vacuum evaporation method.

(2) The etching injection hole 108 may be filled with an insulator such as glass (S102), nitride, alumina, etc. by CVD, sputtering, or vapor deposition.

<Problem to be solved by the invention> However, such an outfit! (1) The tension of the vibrating beam 3 has an influence as a gauge factor GF when used as a strain gauge.

GF=(1/2)<0124 (L/h)' )/(
1+0.24 (L/h) 2ε. ) L: 1i Length of the moving beam 3 h: Thickness of the vibrating beam 3 ε0: The operating point of the tensile strain strain gauge is limited by the processing conditions of the vibrating beam 3, for example, the condition that the boron concentration is 3×10 Igcm-” or higher. , Therefore, the crystal strain in the vibrating beam 3 is 2
It is limited to about 00 to 300μ.

This restriction on the operating point has the disadvantage that the design range that can be selected is narrowed.

(2) The temperature coefficient of the natural frequency of the silicon vibrating beam 3 is -3
0 to 40 PPm/, which is a value based on physical property values.

If this is used as a high-precision sensor, the temperature coefficient is large and the temperature sensor for temperature correction is required to be stable.

As a result, the cost increases, and the stability of the entire device depends on the stability of the temperature sensor.

The present invention solves this problem.

An object of the present invention is to provide a vibrating transducer in which the tension or temperature coefficient of the vibrating beam portion can be easily adjusted.

<Means for Solving the Problems> In order to achieve this object, the present invention provides: (1) a vibrating beam made of silicon single crystal provided on a silicon single crystal substrate; and a gap around the vibrating beam. a shell made of a silicon material that surrounds the vibrating beam and constitutes the substrate and the chamber so that the vibrating beam is maintained; excitation means for exciting the vibrating beam; and excitation detection means for detecting the vibration of the vibrating beam. a first layer made of an oxide film or a nitride film provided covering the surface of the vibrating beam, a second layer made of polysilicon provided covering the surface of the first layer, and the chamber a third layer made of an oxide film or a nitride film provided to cover the inner surface of the third layer; and a fourth layer made of polysilicon provided to cover the surface of the third layer, the first layer and A vibrating transducer characterized in that the tension formed by the vibrating beam, the first layer, and the second layer is adjusted to a predetermined tension by adjusting the thickness of the second layer.

(2) A vibrating beam made of silicon single crystal provided on a silicon single crystal substrate, and a silicon material surrounding the vibrating beam and forming a chamber with the substrate so that a gap is maintained around the vibrating beam. In a vibrating transducer comprising a shell, an excitation means for exciting the vibrating beam, and an excitation detection means for detecting vibration of the vibrating beam, an oxide film or a nitride film provided covering the surface of the vibrating beam is removed. a second layer made of polysilicon and provided to cover the surface of the first layer; and a third layer made of an oxide film or a nitride film provided to cover the inner surface of the chamber; a fourth layer made of polysilicon provided to cover the surface of the third layer, and the film thicknesses of the first layer and the second layer are adjusted to form the vibrating beam, the first layer and the second layer. A vibrating transducer is constructed in which the temperature coefficient formed by the layers is adjusted to a predetermined temperature coefficient.> In the above structure, in the invention set forth in claim 1, ,for example,
It is manufactured as follows.

(1) A silicon oxide or silicon nitride film is formed on an n-type silicon substrate. Required portions of the film are removed by photolithography.

(2) Etching is performed with hydrogen chloride in a high-temperature hydrogen atmosphere to undercut the film at desired locations on the substrate to form recesses.

(3) Selective epitaxial growth is performed in a high temperature hydrogen atmosphere by mixing hydrogen chloride gas into the source gas.

In other words, ■ Due to the high concentration of P-type silicon that is easily etched,
A first epitaxial layer corresponding to the lower half of the vacuum chamber is selectively epitaxially grown.

(2) A second epitaxial layer corresponding to a vibrating beam is selectively epitaxially grown on the surface of the first epitaxial layer using etched, highly-concentrated P-type silicon so as to cover the required locations.

■Highly concentrated P-type silicon that is easily etched,
A third epitaxial layer corresponding to the upper half of the vacuum chamber is selectively epitaxially grown on the surface of the second epitaxial layer.

(2) A fourth epitaxial layer corresponding to a shell is selectively epitaxially grown on the surface of the third epitaxial layer using highly-concentrated P-type silicon that is difficult to be etched.

(4) Etching and removing the silicon oxide or silicon nitride film with hydrofluoric acid and providing an etching inlet.

(5) Apply a positive pulse or positive voltage to the substrate for the fourth layer, inject alkaline solution from the etching injection port, and selectively etch and remove the first epitaxial layer and the third epitaxial layer. .

(6) A film of silicon oxide or silicon nitride is formed over the entire surface.

(7) Form a polysilicon layer on the surface of the silicon oxide film in silane, phosphine, and hydrogen fluid at high temperature in vacuum, and close the etching injection port.

Then, the thicknesses of the first layer and the second layer are adjusted to adjust the tension formed by the vibrating beam, the first layer, and the second layer to a predetermined tension.

In the invention described in claim 2, for example,
It is manufactured as follows.

(1) Required portions of six films forming silicon oxide or silicon nitride films on an n-type silicon substrate are removed by photolithography.

(2) Etching is performed with hydrogen chloride in a high-temperature hydrogen atmosphere to undercut the film at desired locations on the substrate to form recesses.

(3) Selective epitaxial growth is performed by mixing hydrogen chloride gas into the source scum in a high-temperature hydrogen atmosphere.

In other words, ■ Due to the high concentration of P-type silicon that is easily etched,
A first epitaxial layer corresponding to the lower half of the vacuum chamber is selectively epitaxially grown.

(2) A second epitaxial layer corresponding to a vibrating beam is selectively epitaxially grown on the surface of the first epitaxial layer using high-concentration P-type silicon, which is difficult to etch, so as to cover the required locations.

■Highly concentrated P-type silicon that is easily etched,
A third epitaxial layer corresponding to the upper half of the vacuum chamber is selectively epitaxially grown on the surface of the second epitaxial layer.

(2) A fourth epitaxial layer corresponding to a shell is selectively epitaxially grown on the surface of the third epitaxial layer using highly-concentrated P-type silicon that is difficult to be etched.

(4) Etching and removing the silicon oxide or silicon nitride film with hydrofluoric acid and providing an etching inlet.

(5) Apply a positive pulse or positive voltage to the substrate for the fourth layer, inject alkaline solution from the etching injection port, and selectively etch and remove the first epitaxial layer and the third epitaxial layer. .

(6) A film of silicon oxide or silicon nitride is formed over the entire surface.

(7) Form a polysilicon layer on the surface of the silicon oxide film in silane, phosphine, and hydrogen fluid at high temperature in vacuum, and close the etching injection port.

Then, by adjusting the film thicknesses of the first layer and the second layer, the temperature coefficient formed by the vibrating beam, the first layer, and the second layer is adjusted to a predetermined temperature coefficient.

Hereinafter, a detailed explanation will be given based on examples.

<Embodiment> FIG. 1 is an explanatory diagram of the main part configuration of an embodiment of the invention as set forth in claim 1 of the present invention.

In the figure, configurations with the same symbols as in FIG. 6 represent the same functions.

Reference numeral 11 denotes a first layer made of an oxide film or a nitride film provided to cover the surface of the vibrating beam 3.

Reference numeral 12 denotes a second layer made of polysilicon and provided to cover the surface of the first layer 11.

Reference numeral 13 denotes a third layer made of an oxide film or a nitride film provided to cover the inner surface of the chamber 5.

14 is a fourth layer made of polysilicon provided covering the surface of the third layer 13.

Reference numeral 15 denotes a fifth layer made of an oxide film or a nitride film provided to cover the outer surface of the shell 4.

Reference numeral 16 denotes a sixth layer made of polysilicon and provided to cover the surface of the fifth layer 15.

By adjusting the film thicknesses of the first layer 11 and the second layer 12, the tension formed by the vibrating beam 3, the first layer 11, and the second layer 12 is adjusted to a predetermined tension.

In the above configuration, the vibrating transducer of the embodiment shown in FIG. 1 is manufactured as shown in FIG.

(1) As shown in Figure 2 (A>), n-type silicon (10
0) A film 201 of silicon oxide or silicon nitride is formed on the substrate 1 which has been cut into a plane. Required portions 202 of the film 201 are removed by photolithography.

(2) As shown in FIG. 2(B), etching is performed with hydrogen chloride in a hydrogen (H2) atmosphere at 1050°C to undercut the film 201 by etching the required portions 202 on the substrate 1. A recess 203 is formed.

Note that instead of hydrogen chloride, high-temperature steam or oxygen may be used, or anisotropic etching may be performed using an alkaline solution at a temperature of 40 DEG C. to 130 DEG C.

(3) As shown in FIG. 2(C), selective epitaxial growth is performed in a hydrogen (H2) atmosphere at 1050"C by mixing hydrogen chloride gas into the source gas.

That is, (1) the first epitaxial layer 204 corresponding to the lower half of the vacuum chamber 5 is made of P-type silicon with a boron concentration of 10 cm';
Select and epitaxially grow 6 ■ Boron concentration 3X
A second epitaxial layer 205 corresponding to the vibrating beam 3 is selectively epitaxially grown on the surface of the first epitaxial layer 2'04 using 10" cm of P-type silicon so as to close a required location 202.

(2) A third epitaxial layer 206 corresponding to the upper half of the vacuum chamber 5 is selectively epitaxially grown on the surface of the second epitaxial layer 205 using P-type silicon with a boron concentration of 10 cm'.

(2) A 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 with a poron concentration of 3×10 cm − .

(4) As shown in FIG. 2(D), a silicon oxide or silicon nitride film 201 is coated with hydrofluoric acid (HF).
) to provide an etching inlet 208.

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

Second epitaxial layer 205 and first epitaxial layer 2
04 or the third epitaxial layer 206 is due to the boron concentration of 3×10"
This is because when it exceeds cm-3, the etching action is inhibited.

(6) As shown in FIG. 2(F), a silicon oxide or silicon nitride film 209 is formed over the entire surface. In this case, silicon oxide WA209 is formed.

(7) As shown in Figure 2 (G), 950℃, 200T
Silane (SiH4) 0.31/min in o r r
,7. tSphin (PH3) 0.00051/m
A polysilicon layer 211 is formed on the surface of the silicon oxide film 209 under hydrogen conditions of 2001/min, and the etching injection port 208 is closed.

The surface roughness of the polysilicon layer 211 in this case is about 0.1 μm in terms of pitch.

By adjusting the film thicknesses of the first layer 11 and the second layer 12, the tension formed by the vibrating beam 3, the first layer 11, and the second layer 12 is adjusted to a predetermined tension.

As a result, when the vibrating beam 3 is made of boron silicon with a high concentration, the tension T will be approximately 100 to 300 μ depending on the concentration of boron. When the first layer 11 made of an oxide film is formed on the vibrating beam 3, a compressive force is generated, and the tension T of the first layer 11 changes depending on the thickness of the first layer 11. Tension T can be adjusted.

Note that when a silicon nitride film is formed as the first layer 11, tensile force is generated, and the tension of the first layer 11 changes depending on the film thickness, so the tension of the entire vibrating beam portion can be further adjusted. .

Furthermore, a second layer 1 made of polysilicon whose tension is close to 0
2 on the outer surface of the first layer 11, the tension of the entire vibrating beam portion can be brought closer to O, and the tension T of the entire vibrating beam portion can be adjusted more easily.

FIG. 3 shows the relationship between the silicon oxide film thickness A, the silicon nitride film thickness B, and the temperature coefficient α.

The silicon oxide film thickness A is shown by a white circle, and the silicon nitride film thickness B is shown by a black circle.

Here, for example, if the silicon nitride film is 200OA, the thickness will be about 700μ.

If the surface of the vibrating beam 3 is covered with the second layer 12 made of polysilicon with a rough surface, the vibrating beam 3 will not stick to the wall surface of the shell 4, and reliability can be improved.

FIG. 4 is an explanatory diagram of the main part of a practical example of the invention as set forth in claim 1 of the present invention.

In the figure, structures with the same symbols as in FIG. 8 represent the same functions.

Reference numeral 21 denotes a first layer made of an oxide film or a nitride film provided to cover the surface of the vibrating beam 3.

Reference numeral 22 denotes a second layer made of polysilicon and provided to cover the surface of the first layer 21.

Reference numeral 23 denotes a third layer made of an oxide film or a nitride film provided to cover the inner surface of the chamber 5.

A fourth layer 24 is made of polysilicon and is provided to cover the surface of the third layer 23.

25 is a fifth layer formed of an oxide film or a nitride film provided to cover the outer surface of the shell 4.

A sixth layer 26 is made of polysilicon and is provided to cover the surface of the fifth layer 25.

The film thicknesses of the first layer 21 and the second layer 22 are adjusted to adjust the temperature coefficient formed by the vibrating beam 3, the first layer 21, and the second layer 22 to a predetermined temperature coefficient.

In the above configuration, the vibrating transducer of the embodiment shown in FIG. 4 is manufactured as shown in FIG.

(1) As shown in Figure 5(A), n-type silicon (10
0) A film 201 of silicon oxide or silicon nitride is formed on the substrate 1 which has been cut into a plane. Required portions 202 of the film 201 are removed by photolithography.

(2) As shown in Figure 5 (B), hydrogen (
H2) Etching is performed with hydrogen chloride in an atmosphere to etch required portions 202 on the substrate 1 to undercut the film 201 and form recesses 203.

Note that instead of hydrogen chloride, high-temperature steam or oxygen may be used, or anisotropic etching may be performed using an alkaline solution at a temperature of 40 DEG C. to 130 DEG C.

(3) As shown in Figure 5 (C), hydrogen (
H2) Selective epitaxial growth is performed by mixing hydrogen chloride scum into the source scum in an atmosphere.

That is, (1) the first epitaxial layer 2 corresponding to the lower half of the vacuum chamber 5 is made of P-type silicon with a boron concentration of IQ1Qcm-3;
04 is selectively epitaxially grown.

(2) A second epitaxial layer 205 corresponding to the vibrating beam 3 is selectively epitaxially grown on the surface of the first epitaxial layer 204 using P-type silicon with a boron concentration of 3XIO''cm-3 so as to close the required portion 202.

■ P-type silicon with a boron concentration of 10"cm-"
A third epitaxial layer 206 corresponding to the upper half of the vacuum chamber 5 is selectively epitaxially grown on the surface of the second epitaxial layer 205 .

(2) A 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 with a boron concentration of 3×10 cm.

(4) As shown in FIG. 5(D), silicon oxide or silicon nitride llI201 is treated with hydrofluoric acid (H
P) to remove the etching inlet 208.
will be established.

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

Second epitaxial layer 205 and first epitaxial layer 2
04 or the third epitaxial layer 206 because the boron concentration is 3X10"
This is because when it exceeds cm-3, the etching action is inhibited.

(6) As shown in FIG. 5(F), a silicon oxide or silicon nitride film 209 is formed over the entire surface. In this case, a silicon oxide film 209 is formed.

(7) As shown in Figure 5 (G), 950°C2200
In T o r r, silane (SiH4) 0.31/
min, phosphine (PH3>0.00051/
A polysilicon layer 211 is formed on the surface of the silicon oxide film 209 under conditions of 2001/min of hydrogen and the etching injection port 208 is closed.

The surface roughness of the polysilicon layer 211 in this case is about 0.1 μm in terms of pitch.

By adjusting the film thicknesses of the first layer 21 and the second layer 22, the temperature coefficient formed by the vibrating beam 3, the first layer 21, and the second layer 22 is adjusted to a predetermined temperature coefficient.

As a result, when the vibrating beam 3 is made of boron silicon with a high concentration, the temperature coefficient α is determined by the concentration of boron. When the first layer 21 made of an oxide film is formed on this vibrating beam 3, the first layer 2
Since the temperature coefficient of the first layer 21 changes depending on the film thickness of 1, the temperature coefficient of the entire vibrating beam portion can be adjusted to 0.

Note that even if a silicon nitride film is formed as the first layer 21,
Since the temperature coefficient of the first layer 21 changes depending on the film thickness,
The temperature coefficient of the entire vibrating beam section can be adjusted to O.

Furthermore, since the second layer 22 made of polysilicon is provided on the outer surface of the first layer 21, the temperature coefficient of the entire vibrating beam portion can be reduced to 0.
It can also be adjusted more easily.

FIG. 6 shows the relationship between the silicon oxide film thickness A, the silicon nitride film thickness B, and the temperature coefficient α when the vibrating beam 3 has a thickness of 3.5 μm and the second layer 22 has a thickness of 1 μm.

The silicon oxide film thickness A is shown by a white circle, and the silicon nitride film thickness B is shown by a black circle.

FIG. 7 is an explanatory diagram of the main part configuration of a usage example of a vibrating beam manufactured by the apparatus of the present invention.

In the figure, 3 is a vibrating beam. The vibrating beam 3 includes two first vibrators 31 that are fixed to the diaphragm 2 at both ends and are arranged parallel to each other, and a first vibrator that mechanically couples the antinode portions of the vibrations of the first vibrators 31 to each other. 32.

40 applies a direct current magnetic field perpendicular to the vibrating beam 3 using a magnet 30, and an alternating current is applied to both ends of one first vibrator 31 by an input transformer 41, so that the vibrating beam 3 is moved in a direction perpendicular to the magnetic field and current by magnetic induction. It is an excitation means for exciting.

The input cadence 41 is connected to both ends of the first vibrator 31 on one side of the secondary side.

Reference numeral 50 denotes vibration detection means for detecting the electromotive force generated at both ends of the other first vibrator 31. In this case, an output transformer 51 and an amplifier 52 are used. Dekadransu 5
The primary side of 1 is connected to both ends of the other first vibrator 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, As a whole, a positive feedback automatic oscillation circuit is constructed. The vibration of the vibrating beam 3 is detected by the vibration detection means 50 and taken out as an output signal.

In the above-mentioned embodiment, the fifth layer 1 made of an oxide film or a nitride film provided covering the outer surface of the shell 4 is
5 and the sixth layer 16 made of polysilicon provided to cover the surface of the fifth layer 15 have been described, but the structure is not limited thereto. For example, an oxide film or a nitride film on the outer surface of the shell 4 has been described. The fifth layer 15 made of a film may be removed and epitaxially grown to provide an epitaxially grown layer made of silicon single crystal.In short, any structure that can seal the vibrating beam 3 may be used.

<Effects of the Invention> As explained above, the present invention provides: (1) a vibrating beam made of silicon single crystal provided on a silicon single crystal substrate; A vibrating transducer comprising: a shell made of a silicon material surrounding a vibrating beam and constituting the substrate and a chamber; excitation means for exciting the vibrating beam; and excitation detection means for detecting vibration of the vibrating beam. a first layer made of an oxide film or a nitride film provided to cover the surface of the beam; a second layer made of polysilicon provided to cover the surface of the first layer; and a second layer made of polysilicon provided to cover the inner surface of the chamber. A third layer made of an oxide film or a nitride film provided, and a fourth layer made of polysilicon provided covering the surface of the third layer, and the film thickness of the first layer and the second layer is A vibrating transducer characterized in that the tension formed by the vibrating beam, the first layer, and the second layer is adjusted to a predetermined tension by adjusting.

(2) A vibrating beam made of silicon single crystal provided on a silicon single crystal substrate, and a silicon material surrounding the vibrating beam and forming a chamber with the substrate so that a gap is maintained around the vibrating beam. A vibrating transducer comprising: a shell; excitation means for exciting the vibrating beam; and BJ vibration detection means for detecting vibrations of the vibrating beam; a second layer made of polysilicon and provided to cover the surface of the first layer; and a third layer made of an oxide film or a nitride film provided to cover the inner surface of the chamber. , a fourth layer made of polysilicon provided covering the surface of the third layer, and adjusting the film thicknesses of the first layer and the second layer to form a structure between the vibrating beam, the first layer and the second layer. A vibrating transducer characterized by adjusting the temperature coefficient formed by two layers to a predetermined temperature coefficient.

As a result, according to the invention recited in claim 1, when the vibrating beam is made of boron silicon with a high concentration, the tension is about 100 to 300 μ depending on the concentration of boron. When a first layer of oxide film is formed on this vibrating beam, compressive force is generated, and the tension of the first layer changes depending on the thickness of the first layer, so the tension of the entire vibrating beam part can be adjusted. I can do it.

Note that when a silicon nitride film is formed as the first layer, a tensile force is generated, and the tension of the first layer changes depending on the film thickness, so that the tension of the entire vibrating beam portion can be further adjusted.

Furthermore, since a second layer made of polysilicon with a tension close to 0 is provided on the outer surface of the first layer, the tension of the entire vibrating beam can be brought close to 0, and the tension of the entire vibrating beam can be reduced to zero. Tension can be adjusted more easily.

Note that if the surface of the vibrating beam is covered with a second layer made of polysilicon with a rough surface, the vibrating beam will not stick to the wall surface of the shell, and reliability can be improved.

Furthermore, according to the invention set forth in claim 2, when the vibrating beam is made of boron silicon with a high concentration, the temperature coefficient is determined by the concentration of boron.

When a first layer of oxide film is formed on this vibrating beam, the first
The temperature coefficient of the first layer changes depending on the thickness of the layer, so
The temperature coefficient of the entire vibrating beam section can be adjusted to zero.

Note that even if a silicon nitride film is formed as the first layer, the temperature coefficient of the first layer 1 changes depending on the film thickness, so the temperature coefficient of the entire vibrating beam portion can be adjusted to zero.

Further, since the second layer made of polysilicon is provided on the outer surface of the first layer, the temperature coefficient of the entire vibrating beam portion can be adjusted to O more easily.

Therefore, according to the present invention, it is possible to realize a vibrating transducer in which the tension or temperature coefficient of the vibrating beam portion can be easily adjusted.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the main part configuration of an embodiment of the present invention, FIG. 2 is an explanatory diagram of the process of FIG. 1, FIG. 3 is an explanatory diagram of the operation of FIG. FIG. 5 is an explanatory diagram of the main part configuration of the embodiment, FIG. 5 is a process explanatory diagram of FIG. 4, FIG. 6 is an explanatory diagram of the operation of FIG. , FIG. 8 is an explanatory diagram of the configuration of a conventional example commonly used,
9 is a cross-sectional view taken along the line A-A in FIG. 8, and FIG. 10 is an explanatory diagram of the manufacturing process in FIG. 8. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Measurement tire phragm, 3... Vibration beam, 4... Shell, 5... Vacuum chamber, 11... First
layer, 12... second layer, 13... third layer, 14...
4th layer, 15...5th layer, 16...6th layer, 21.
...First layer, 22...Second layer, 23...Third layer, 2
4... Fourth layer, 25... Fifth layer, 26... Sixth layer, 30... Magnet, 31... First vibrator, 32...
Second vibrator, 40... Excitation means, 41... Input voltage lance, 42... Input terminal, 50... Vibration detection means,
51... Output Lance, 52... Amplifier, 53...
・Output terminal, 201...membrane, 202...required location,
203... Recessed portion, 204... First epitaxial layer, 205... Second epitaxial layer, 206... Third epitaxial layer, 207... Fourth epitaxial layer, 208... Etching injection port, 209...Silicon oxide film, 211...Polysilicon layer, 301...
・Membrane, 302... Required location, 303... Recess, 30
4... First epitaxial layer, 305... Second epitaxial layer, 306... Third epitaxial layer, 3
07... Fourth epitaxial layer, 308... Etching injection port, 309... Silicon oxide film, 311...
polysilicon layer. Figure O5 1r Figure Figure Figure Figure Figure ε Figure Figure Figure

Claims (2)

[Claims] (1) A vibrating beam made of silicon single crystal provided on a silicon single crystal substrate, and a silicon material surrounding the vibrating beam and forming a chamber with the substrate so as to maintain a gap around the vibrating beam. In a vibrating transducer comprising a shell, an excitation means for exciting the vibrating beam, and an excitation detection means for detecting vibration of the vibrating beam, an oxide film or a nitride film provided covering the surface of the vibrating beam is removed. a second layer made of polysilicon and provided to cover the surface of the first layer; and a third layer made of an oxide film or a nitride film provided to cover the inner surface of the chamber; a fourth layer made of polysilicon provided covering the surface of the third layer, and adjusting the film thicknesses of the first layer and the second layer to form a structure between the vibrating beam, the first layer and the second layer. A vibrating transducer characterized by adjusting the tension formed by two layers to a predetermined tension. (2) A vibrating beam made of silicon single crystal provided on a silicon single crystal substrate, and a silicon material surrounding the vibrating beam and forming a chamber with the substrate so that a gap is maintained around the vibrating beam. In a vibrating transducer comprising a shell, an excitation means for exciting the vibrating beam, and an excitation detection means for detecting vibration of the vibrating beam, an oxide film or a nitride film provided covering the surface of the vibrating beam is removed. a second layer made of polysilicon and provided to cover the surface of the first layer; and a third layer made of an oxide film or a nitride film provided to cover the inner surface of the chamber; a fourth layer made of polysilicon provided covering the surface of the third layer, and adjusting the film thicknesses of the first layer and the second layer to form a connection between the vibrating beam and the first layer. A vibrating transducer characterized in that the temperature coefficient formed by the second layer is adjusted to a predetermined temperature coefficient.