JPH073310Y2 - Semiconductor differential pressure measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a semiconductor differential pressure measuring device capable of automatically correcting a sensitivity change of the device.

<Prior Art> FIG. 7 is an explanatory view of a configuration of a conventional example which is generally used in the past.

In the figure, 1 is a sensor chip made of a semiconductor.

11 is provided in the sensor chip 1, and the sensor chip 1 has
It is a recess that forms the diaphragm 12.

Reference numeral 13 is a semiconductor strain gauge provided on the diaphragm 12.

Reference numeral 2 is a substrate having one surface fixed to the sensor chip 1 and forming the recess 11 and the first measurement chamber 21.

Reference numeral 22 is a through hole penetrating the substrate 2 and communicating with the first measurement chamber 21.

Reference numeral 3 is a pipe whose one end is connected to the other surface of the substrate 2 and which communicates with the through hole 22 and into which one measuring pressure is introduced from the other end.

4 is a base to which the pipe 3 is fixed.

Reference numeral 5 denotes a body having one end fixed to the base 4 and forming the base 4, the sensor chip 1 and the second measurement chamber 51.

Reference numeral 52 is a recess provided on the other end of the body 5.

Reference numeral 6 denotes a liquid contact diaphragm which is provided in the body 5 and constitutes the recess 52 and the liquid contact chamber 61.

Reference numeral 53 is a communication hole that is provided in the body 5 and connects the second measurement chamber 51 and the liquid contact chamber 61.

501 is a filled liquid that fills the second measurement chamber 51, the liquid contact chamber 61, and the communication hole 53.

62 is a cover for covering the liquid contact diaphragm 6.

In the above configuration, when the measurement pressure P1 is applied to the pipe 3 and the measurement pressure P2 is applied to the wetted diaphragm 6, the diaphragm
A differential pressure between the measured pressure P1 and the measured pressure P2 is applied to 12, and this differential pressure is detected by the semiconductor strain gauge 13.

<Problems to be Solved by the Invention> However, in such a device, the sensitivity of the semiconductor strain gauge 13 affects the influence of impurity ions and the influence of the change in the bonding state of the silicon diaphragm 12 between the sensor chip 1 and the substrate 2. Gradually change by receiving.

For this reason, a so-called calibration is sometimes performed by applying an accurate input, but the calibration cannot be performed when an accurate input cannot be obtained.

The present invention solves this problem.

An object of the present invention is to provide a semiconductor differential pressure measuring device capable of automatically correcting the sensitivity change of the device.

<Means for Solving the Problems> In order to achieve this object, the present invention is provided with a sensor chip made of a semiconductor, a concave portion provided in the sensor chip to form a diaphragm in the sensor chip, and provided in the diaphragm. A semiconductor strain gauge, a substrate of which one surface is fixed to the sensor chip and which forms the recess and the first measurement chamber, a through hole which penetrates the substrate and communicates with the first measurement chamber, and the other surface of the substrate. A pipe, one end of which is connected to the through hole and one measurement pressure is introduced from the other end, a base to which the pipe is fixed, one end of which is fixed to the base, the sensor chip, and a second measurement A body forming a chamber, a recess provided at the other end of the body, a wetted diaphragm that forms a wetted chamber with the recessed portion provided in the body and receives the measurement pressure of the other, and a body A communication hole provided to communicate the second measurement chamber and the liquid contact chamber, an internal void provided in the body, a bimorph type piezoelectric diaphragm dividing the internal void into two chambers, and the internal A connection hole connecting the space, the second measurement chamber and the liquid contact chamber,
A semiconductor differential pressure measuring device comprising the internal space, the second measurement chamber, the liquid contact chamber, the communication hole, and a filled liquid filling the connection hole.

<Operation> In the above configuration, one measuring pressure is applied to the pipe,
When the other measuring pressure is applied to the liquid contact diaphragm, the differential pressure between one measuring pressure and the other measuring pressure is applied to the diaphragm.
This differential pressure is detected by a semiconductor strain gauge.

When an alternating voltage is applied to the piezoelectric diaphragm during calibration of the device, one side of the piezoelectric diaphragm expands and the other side contracts, and the piezoelectric diaphragm is bent and displaced as a whole.

With the bending displacement of the piezoelectric diaphragm, the enclosed liquid moves, and the diaphragm receives pressure. , This pressure is
It depends on the density of the filled liquid and the speed of the filled liquid discharged from the connection hole. The sensitivity of the semiconductor differential pressure measuring device can be calibrated by previously obtaining the relationship between the piezoelectric diaphragm driving conditions of the voltage and frequency applied to the piezoelectric diaphragm and the pressure received by the diaphragm.

Hereinafter, detailed description will be given based on examples.

<Embodiment> FIG. 1 is an explanatory view of a main part configuration of an embodiment of the present invention.

In the figure, the same symbols as those in FIG. 7 represent the same functions.

Only parts different from those in FIG. 7 will be described below.

Reference numeral 81 is an internal void provided in the body 5.

Reference numeral 82 is a bimorph type piezoelectric diaphragm that divides the internal space 81 into two chambers.

Reference numeral 83 is a connection hole that connects the internal space 81, the second measurement chamber 51, and the liquid contact chamber 61.

Reference numeral 84 is a filled liquid that fills the internal space 81, the second measurement chamber 51, the liquid contact chamber 61, the communication hole 53, and the connection hole 83.

In the above configuration, when one measuring pressure P1 is applied to the pipe 3 and the other measuring pressure P2 is applied to the liquid contact diaphragm 6,
A differential pressure between one measurement pressure P1 and the other measurement pressure P2 is applied to the diaphragm 12, and this differential pressure is detected by the semiconductor strain gauge 13.

When an alternating voltage is applied to the piezoelectric diaphragm 82 during calibration of the device, as shown in FIG. 2, one side of the piezoelectric diaphragm 82 expands and the other side contracts, and the piezoelectric diaphragm 82 is bent and displaced as a whole.

With the bending displacement of this piezoelectric diaphragm 82, the enclosed liquid
84 moves and diaphragm 12 receives pressure. FIG. 3 shows the case where the pressure is applied. Fig. 4 shows the diaphragm
Indicates the state of dynamic pressure that 12 receives. This peak-to-peak value + P--p is detected.

This pressure depends on the density of the filled liquid 84 and the speed of the filled liquid 84 discharged from the connection hole 83. The sensitivity of the semiconductor differential pressure measuring device can be calibrated by previously obtaining the relationship between the piezoelectric diaphragm driving conditions of the voltage and frequency applied to the piezoelectric diaphragm 82 and the pressure received by the diaphragm 12. FIG. 5 shows an example when the drive frequency f = foHz.

As a result, (1) the sensitivity can be calibrated without applying an input pressure for calibration.

(2) It can be easily automated by combining it with a microprocessor or the like.

(3) Further, it is possible to detect damage to the liquid contact diaphragm 6.

(4) The voltage-potential characteristics of the piezoelectric element tend to have hysteresis, but the piezoelectric diaphragm 82 is in the enclosed liquid 84,
Since the bypass passage 53 for the filled liquid 84 is provided, even if the piezoelectric diaphragm 82 has hysteresis, the shift of the zero point does not occur.

FIG. 6 shows an example of a system in which the semiconductor differential pressure measuring apparatus is configured to be automatically calibrated.

In the figure, 91 is the present semiconductor differential pressure measuring device, 92 is a piezoelectric diaphragm 82 drive unit, 93 is a pressure conversion unit, and 94 is a control unit.

In addition, in the above-mentioned embodiment, the differential pressure measuring device for measuring the differential pressure of the measured pressure has been described, but it goes without saying that one measured pressure may be used as a reference pressure and used as a pressure gauge.

<Effects of the Invention> As described above, the present invention includes a sensor chip made of a semiconductor, a concave portion provided on the sensor chip to form a diaphragm on the sensor chip, and a semiconductor strain gauge provided on the diaphragm. A substrate whose one surface is fixed to the sensor chip and which forms the recess and the first measurement chamber;
A through hole penetrating the substrate and communicating with the first measuring chamber; a pipe having one end connected to the other surface of the substrate and communicating with the through hole, and one measuring pressure being introduced from the other end; A base that is fixed, and a body that has one end fixed to the base and forms the base, the sensor chip, and a second measurement chamber,
A concave portion provided at the other end of the body, a wetted diaphragm that is provided in the body to form a liquid contact chamber with the concave portion, and a wetted diaphragm that receives the measurement pressure of the other body, and the second measurement chamber and the A communication hole that communicates with the liquid contact chamber, an internal cavity provided in the body, a bimorph piezoelectric diaphragm that divides the internal cavity into two chambers, the internal cavity and the second measurement chamber. Semiconductor differential pressure measurement comprising a connection hole connecting the liquid contact chamber, the internal space, the second measurement chamber, the liquid contact chamber, the communication hole, and a filling liquid filling the connection hole. Configured the device.

As a result, (1) the sensitivity can be calibrated without applying an input pressure for calibration.

(2) It can be easily automated by combining it with a microprocessor or the like.

(3) Further, it is possible to detect breakage of the liquid contact diaphragm.

(4) The voltage-potential characteristics of the piezoelectric element tend to have hysteresis, but since the piezoelectric diaphragm is in the filled liquid and a bypass passage for the filled liquid is provided, even if there is hysteresis in the piezoelectric diaphragm, it is zero. It does not shift the points.

Therefore, according to the present invention, it is possible to realize a semiconductor differential pressure measuring device capable of automatically correcting the sensitivity change of the device.

[Brief description of drawings]

FIG. 1 is an explanatory view of the essential parts of an embodiment of the present invention, FIG. 2 is an explanatory view of the essential parts of FIG. 1, and FIGS. 3 to 5 are operational explanatory views of FIG. 1 and FIG. Further, FIG. 7 is an explanatory view of the configuration of a conventional system which is generally used in the past, which is an example of a system in which the semiconductor differential pressure measuring apparatus is configured to be automatically calibrated. 1 ... Sensor chip, 11 ... Recessed portion, 12 ... Diaphragm, 13 ...
Semiconductor strain gauge, 2 ... Substrate, 21 ... First measuring chamber, 22 ... Through hole, 3 ... Pipe, 4 ... Base, 5 ... Body, 51 ... Second
Measuring chamber, 52 ... Recessed portion, 53 ... Communication hole, 6 ... Wetted diaphragm, 61 ... Wetted chamber, 62 ... Cover, 81 ... Internal space, 82 ... Piezo diaphragm, 83 ... Connection hole, 84 ... Filled liquid, 91 ... This semiconductor differential pressure measuring device, 92 ... Piezoelectric diaphragm drive section, 93 ... Pressure conversion section, 94 ... Control section.

Claims (1)

[Scope of utility model registration request] 1. A sensor chip made of a semiconductor, a concave portion provided on the sensor chip to form a diaphragm on the sensor chip, a semiconductor strain gauge provided on the diaphragm, and a concave portion having one surface fixed to the sensor chip. And a substrate forming the first measurement chamber, a through hole penetrating the substrate and communicating with the first measurement chamber, and one end connected to the other surface of the substrate and communicating with the through hole, and one measurement from the other end A pipe into which pressure is introduced, a base to which the pipe is fixed,
A body having one end fixed to the base and forming the base, the sensor chip and the second measurement chamber, a recess provided at the other end of the body, and a recess provided at the body and the liquid contact chamber. A wetted diaphragm that receives the other measurement pressure,
A communication hole provided in the body for communicating the second measurement chamber with the liquid contact chamber; and an internal space provided in the body,
A bimorph type piezoelectric diaphragm that divides the internal space into two chambers, a connection hole that connects the internal space, the second measurement chamber, and the liquid contact chamber, the internal space and the second measurement. A semiconductor differential pressure measuring apparatus comprising: a chamber, the liquid contact chamber, a communication liquid, and a filling liquid filling the connection hole.