JP2002243567A - Semiconductor type pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor type pressure sensor capable of detecting the pressure with high sensitivity without reducing the accuracy of pressure detection even in a micro-pressure measuring field. SOLUTION: This pressure sensor 10 for high temperature measurement is equipped with a sapphire diaphragm 13 for receiving the pressure of a device under test, a plurality of pressure-sensitive resistance element parts 20 laminated along the circumferential direction of the sapphire diaphragm 13 to constituted a Wheatstone bridge, a plurality of amplification parts 23 for amplifying pressure signals from the plurality of pressure-sensitive resistance element parts 20, respectively, and an addition processing part 25 for adding the pressure signals from the plurality of amplification parts 23. In the sensor, the pressure applied to the outside of the diaphragm 13 is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor pressure sensor capable of detecting pressure with high sensitivity without deteriorating the accuracy of pressure detection even in the field of minute pressure measurement.

[0002]

2. Description of the Related Art A semiconductor type pressure sensor detects a fluid pressure of a gas or a liquid by a pressure-sensitive resistance element laminated on a crystalline sapphire diaphragm.

A conventional semiconductor pressure sensor is disclosed in, for example, Japanese Patent Publication No. Hei 5-507150.
FIG. 4 shows an external view of the mounting of the conventional semiconductor pressure sensor 30.

[0004] As shown in FIG.
Numeral 0 is attached to a pressure sensor attaching portion 39 provided on a transport pipe for transporting high-temperature gas or liquid, and detects a fluid pressure applied as indicated by an arrow P.

FIG. 5 is a sectional view of a conventional semiconductor pressure sensor 30. As shown in FIG.

[0006] As shown in FIG.
0 is a cylindrical ceramic body main body 31;
A circular thin plate-shaped crystalline sapphire diaphragm 33 which is attached to an end of the body main body 31 via a bonding layer 32 and receives fluid pressure of gas or liquid;
A pressure-sensitive resistor element portion 34 laminated on the crystalline sapphire diaphragm 33 at the position of the concave portion 31a formed at the position, a signal line 37 connected to the pressure-sensitive resistor element portion 34, and a screw portion 35
It is composed of

When detecting the fluid pressure of a high-temperature gas or liquid flowing in the transport pipe by the semiconductor pressure sensor 30, the semiconductor pressure sensor 30 is attached to the pressure sensor mounting portion 39.
When a fluid pressure of a gas or a liquid is applied to the crystalline sapphire diaphragm 33 as shown by an arrow P, the crystalline sapphire diaphragm 33 receives the pressure and bends toward the concave portion 31a, and the pressure-sensitive resistance element portion The change in pressure is output from the signal line 37 by 34, and pressure detection is performed.

[0008]

However, the conventional semiconductor pressure sensor 30 has the following problems.

As described above, the semiconductor pressure sensor 30 can detect the fluid pressure of the gas or liquid flowing in the transport pipe by the deflection of the crystalline sapphire diaphragm 33. Of the sapphire diaphragm 33 is small and the value of the pressure signal output from the pressure-sensitive resistance element section 34 is small. As a result, the accuracy of pressure detection may be significantly reduced.

The present invention has been made in view of the above, and provides a semiconductor pressure sensor capable of detecting pressure with high sensitivity without deteriorating the accuracy of pressure detection even in the field of minute pressure measurement. The purpose is to:

[0011]

According to the present invention, there is provided a semiconductor pressure sensor comprising a crystalline sapphire diaphragm which receives a pressure of an object to be measured, and a whistestone bridge circuit which is laminated along the circumferential direction of the sapphire diaphragm. A plurality of pressure-sensitive resistor elements, a plurality of amplifiers for amplifying pressure signals from the plurality of pressure-sensitive resistor elements, and an addition processor for adding the pressure signals from the plurality of amplifiers. The pressure applied to the outside of the sapphire diaphragm is detected.

Further, the pressure-sensitive resistor elements are arranged at equal intervals along the circumferential direction.

[0013] Further, the addition processing section excludes the pressure signal which differs from the pressure signal value of the group of pressure signals approximate to each other by a predetermined value or more from the plurality of input pressure signals. .

Further, the semiconductor pressure sensor of the present invention comprises a crystalline sapphire diaphragm which receives the pressure of the object to be measured, and a plurality of sensors which are laminated along the circumferential direction of the sapphire diaphragm to form a whistestone bridge circuit. A piezoresistive element section, a plurality of first amplifying sections for respectively amplifying pressure signals from the plurality of pressure-sensitive resistive element sections, and a first amplifying section for amplifying pressure signals from the plurality of pressure-sensitive resistive element sections.
A plurality of second amplifying units having different amplification factors from the amplifying unit; and an addition processing unit for switching and inputting the pressure signals from the plurality of the first amplifying units and the plurality of the second amplifying units and adding the signals, and the sapphire diaphragm. It was decided to detect the pressure applied to the outside.

Further, the sapphire diaphragm includes:
At least one of the amplifier and the addition processing unit is formed by lamination in addition to the pressure-sensitive resistance element unit.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a semiconductor pressure sensor 10 according to an embodiment of the present invention.

As shown in FIG. 1, the semiconductor type pressure sensor 10 has a crystalline sapphire diaphragm 13 (hereinafter referred to as a sapphire diaphragm) in which a pressure-sensitive resistance element section 20 is laminated, a cylindrical section 11A and a bottom section 11B. And the bottom 11
B, a pressure introducing portion 11c is formed, and the body main body 1
1 and a screw portion 1 attached to the body main body 11
5, the sapphire diaphragm 13 is used as a pressure receiving portion, and the pressure applied to the outside of the sapphire diaphragm 13 from the pressure introducing portion 11c is detected.

The sapphire diaphragm 13 is joined to a supporting portion 11e containing alumina as a main component.

The body main body 11 has a pressure introducing portion 11c.
And the sapphire diaphragm 13 is formed so as to directly receive pressure. Further, the support portion 11e is provided with a groove 11d along the circumferential direction to make the sapphire diaphragm 13 easily bendable.

The pressure-sensitive resistance element section 20 is formed by stacking, for example, a P-type semiconductor element on the sapphire diaphragm 13 by applying a semiconductor manufacturing technique. A plurality of the pressure-sensitive resistance element sections 20 can be set at predetermined positions described later. The length and cross-sectional area of the pressure-sensitive resistive element portion 20 change due to the deflection of the pressure-sensitive resistor portion 20 due to the pressure, and the pressure signal corresponding to the pressure is changed to a signal line using a Wheatstone bridge circuit configuration. Output via 17.

When the semiconductor pressure sensor 10 detects the fluid pressure of gas or liquid flowing in the transport pipe, the semiconductor pressure sensor 10 is mounted on a mounting portion (not shown) provided on the transport pipe by a screw portion 15. When a fluid pressure is applied to the sapphire diaphragm 13 from the pressure introducing portion 11c as shown by an arrow P, the sapphire diaphragm 13
Bends inward. Its deflection is sapphire diaphragm 13
The pressure is detected as a pressure signal by the pressure-sensitive resistance element unit 20 laminated on the sensor and the pressure is detected.

FIG. 2 shows a sapphire diaphragm 13 for laminating the pressure-sensitive resistor elements 20, and FIG. 2A shows a sapphire diaphragm 13 for laminating the pressure-sensitive resistive elements 20.
2B is a plan view, and FIG. 2B is an enlarged view of FIG.

As shown in FIG. 2A, the sapphire diaphragm 13 has four pressure-sensitive resistor elements 20A, 20A.
B, 20C, and 20D are laminated at equal intervals in the direction of the circumference 13A, and the pressure-sensitive resistor elements 20A, 20B, 20C, and 20D
Are connection parts 21A1, 21A2, 21A3, 2
1A4. The circumference 13A is where the stress of the pressure applied to the sapphire diaphragm 13 is large, and the pressure can be effectively detected near this.

As shown in FIG. 2 (B), the pressure-sensitive resistance element section 20A has a structure in which four pressure-sensitive resistance elements 20A1, 20A2, 20A3, 20A4 are laminated on a sapphire diaphragm 13, and connection sections 21A1, 21A2, 21A3 are formed. , 21A4
Connected to

The connection part 21A1 is connected to the pressure-sensitive resistance element 20A1.
And the pressure-sensitive resistance element 20A2,
2 is an end of the pressure-sensitive resistance element 20A1 and the end of the pressure-sensitive resistance element 20A1.
A3, the connection 21A3 is connected between the pressure-sensitive resistance element 20A3 and the pressure-sensitive resistance element 20A4, and the connection 21A4 is connected to the end of the pressure-sensitive resistance element 20A2 and the pressure-sensitive resistance 20A4. And a Wheatstone bridge circuit.

The pressure-sensitive resistance element section 20B shown in FIG.
A Wheatstone bridge circuit is formed in each of 20C and 20D, similarly to the pressure-sensitive resistance element unit 20A.

FIG. 3 shows a pressure detecting circuit according to an embodiment of the present invention.

As shown in FIG. 3, this pressure detection circuit
A pressure-sensitive resistance element section 20A, 20B, 20C, 20D in which the Wheatstone bridge circuit shown in FIG. 2 is formed, a constant-voltage power supply section 22 for applying a constant voltage to the pressure-sensitive resistance element sections 20A, 20B, 20C, 20D. , Pressure-sensitive resistance element section 20A, 2
It comprises amplifiers 23A, 23B, 23C and 23D for amplifying the pressure signals from 0B, 20C and 20D, respectively, and an addition processing unit 25 for adding the amplified pressure signals.

The addition processing section 25 includes amplifiers 23A and 23A.
The amplified pressure signals from B, 23C and 23D are added and output as a pressure detection signal of the semiconductor pressure sensor 10 (see FIG. 1). Even if any of the amplifiers 23A, 23B, 23C, and 23 has a variation in amplification degree, the influence on the detection accuracy of the pressure detection signal is small.
Even if any of A, 20B, 20C, and 20D varies, the influence on the detection accuracy of the pressure detection signal is small.

The addition processing section 25 includes an amplifier 23A,
The pressure signal values from 23B, 23C, and 23D are compared, and when any one of the pressure signal values is larger than a predetermined value, the pressure signal value is excluded and corrected. A detection signal can be output, and the accuracy of the pressure detection signal does not decrease.

When the pressure is detected by the pressure detecting circuit, pressure signals are respectively detected from the pressure-sensitive resistor elements 20A, 20B, 20C and 20D in which a Wheatstone bridge circuit is formed by the pressure applied to the sapphire diaphragm 13. , The pressure signals are amplifiers 23A, 2A, respectively.
The signals are amplified by 3B, 23C, and 23D, added by the addition processing unit 25, and output as pressure detection signals. In addition, the addition processing unit 25 excludes the pressure signal value when any one of the pressure signal values of the amplified and input pressure signals is larger than a predetermined value and the difference between the pressure signal value and the other pressure signal group value. The detected pressure detection signal is output.

Incidentally, the addition processing section 25 can be formed of an ASIC (integrated circuit for specific application), and in addition to the pressure-sensitive resistance element sections 20A, 20B, 20C, and 20D, the amplifier 2
The 3A, 23B, 23C, 23D and the addition processing unit 25 can also be formed on the sapphire diaphragm 13 to form a simple structure.

Further, the semiconductor pressure sensor 10 detects the fluid pressure of the gas or liquid flowing in the transport pipe. However, the present invention is not limited to this, and the pressure in the container can be detected.

As described above, the semiconductor pressure sensor 10 includes the pressure-sensitive resistance element section 20 in which the Wheatstone bridge circuit is formed.
A, 20B, 20C, and 20D respectively detect pressure signals, and convert the pressure signals into amplifiers 23A, 23B, and 23, respectively.
By amplifying and adding by C and 23D and outputting a pressure detection signal, pressure can be detected with high sensitivity even in the field of minute pressure measurement without lowering accuracy.

In the above embodiment, the semiconductor pressure sensor 10 has four pressure-sensitive resistor elements 20A, 20B and 20.
The example in which C and 20D are provided has been described. However, the present invention is not limited to this. A plurality of pressure-sensitive resistor elements 20 can be provided to amplify and add the pressure signal and output a pressure detection signal. Among the plurality of input pressure signals, a pressure signal that differs from a pressure signal value of a pressure signal group similar to each other by a predetermined value or more can be excluded.

[0037]

According to the semiconductor pressure sensor of the present invention, there is provided a crystalline sapphire diaphragm which receives a pressure of an object to be measured;
A plurality of pressure-sensitive resistor elements that are stacked along the circumferential direction of the sapphire diaphragm to form a Whistone bridge circuit, and a plurality of amplifiers that amplify pressure signals from the plurality of pressure-sensitive resistor elements, respectively. An addition processing unit that adds the pressure signals from the plurality of amplifying units to detect the pressure applied to the outside of the sapphire diaphragm. Pressure can be detected with sensitivity.

Further, since the pressure-sensitive resistor elements are arranged at equal intervals along the circumferential direction, pressure signals can be detected in a well-balanced manner from the pressure-sensitive resistor elements, and the accuracy of pressure detection is reduced. The pressure can be detected with high sensitivity without the need.

In addition, the addition processing section excludes the pressure signal which differs from the pressure signal value of the pressure signal group approximate to each other by a predetermined value or more from the plurality of input pressure signals. Even if the pressure signals from the plurality of amplifying units vary, the pressure can be detected with high sensitivity without lowering the pressure detection accuracy.

Further, the semiconductor pressure sensor of the present invention comprises a crystalline sapphire diaphragm which receives the pressure of the object to be measured, and a plurality of sensors which are laminated along the circumferential direction of the sapphire diaphragm to form a whistestone bridge circuit. A piezoresistive element section, a plurality of first amplifying sections for respectively amplifying pressure signals from the plurality of pressure-sensitive resistive element sections, and a first amplifying section for amplifying pressure signals from the plurality of pressure-sensitive resistive element sections.
The sapphire diaphragm, comprising: a plurality of second amplifying units having different amplification factors from the amplifying unit; and an addition processing unit configured to switch input and add pressure signals from the plurality of first amplifying units and the plurality of second amplifying units. Since the pressure applied to the outside of the sensor is detected, even in the field of minute pressure measurement, it is possible to detect pressures with different sensitivity and high sensitivity without lowering the accuracy of pressure detection.

Further, the sapphire diaphragm is
In addition to the pressure-sensitive resistance element section, at least one of the amplifier and the addition processing section is formed by lamination,
A simple structure can be adopted, and pressure can be detected with high sensitivity without lowering pressure detection accuracy.

[Brief description of the drawings]

FIG. 1 is a sectional view of a semiconductor pressure sensor according to an embodiment of the present invention.

FIG. 2A is a plan view of a sapphire diaphragm for laminating a pressure-sensitive resistance element, and FIG. 2B is a partially enlarged view of the sapphire diaphragm.

FIG. 3 shows a pressure detection circuit according to an embodiment of the present invention.

FIG. 4 shows a mounting external view of a conventional semiconductor pressure sensor.

FIG. 5 shows a sectional view of a conventional semiconductor pressure sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Semiconductor type pressure sensor 11 Body main part 11A Cylindrical part 11B Bottom part 11c Pressure introduction part 11d Groove 11e Support part 12 Joining layer 13 Sapphire diaphragm 15 Screw part 20A, 20B, 20C, 20D Pressure sensitive resistance element part 21A1, 21A2, 21A3, 21A4 connection unit 22 constant voltage power supply unit 23A, 23B, 23C, 23D amplifier 25 addition processing unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F055 AA40 BB20 CC02 DD04 DD19 EE13 FF11 GG16 GG31 4M112 CA04 CA07 CA12 CA13 CA15 EA20 FA01

Claims (5)

[Claims] 1. A crystalline sapphire diaphragm which receives a pressure of an object to be measured, a plurality of pressure-sensitive resistance element portions laminated along a circumferential direction of the sapphire diaphragm to form a whitstone bridge circuit, and A plurality of amplifying sections for amplifying the pressure signal from the pressure-sensitive resistance element section,
A semiconductor pressure sensor, comprising: an addition processing unit that adds pressure signals from a plurality of the amplifying units, and detects a pressure applied to the outside of the sapphire diaphragm. 2. The semiconductor pressure sensor according to claim 1, wherein the pressure-sensitive resistor elements are arranged at equal intervals along the circumferential direction. 3. The method according to claim 2, wherein the adding unit excludes, from the plurality of input pressure signals, the pressure signals that differ from the pressure signal values of the pressure signal group approximate to each other by a predetermined value or more. The semiconductor pressure sensor according to claim 1, wherein 4. A crystalline sapphire diaphragm which receives a pressure of an object to be measured, a plurality of pressure-sensitive resistor elements laminated along a circumferential direction of the sapphire diaphragm to form a Whiston bridge circuit, and A plurality of first amplifying sections for respectively amplifying the pressure signals from the pressure-sensitive resistance element sections; and a plurality of first amplifying sections for respectively amplifying the pressure signals from the plurality of pressure-sensitive resistance element sections and having different amplification factors from the first amplification section. 2 amplifying section, and an addition processing section for selectively inputting and adding the pressure signals from the plurality of first amplifying sections and the plurality of second amplifying sections, and detecting the pressure applied to the outside of the sapphire diaphragm. Characteristic semiconductor pressure sensor. 5. The semiconductor device according to claim 1, wherein the sapphire diaphragm is formed by laminating at least one of the amplifier and the addition processing unit in addition to the pressure-sensitive resistance element unit. Pressure sensor.