JPH0395425A - Semiconductor device for measuring differential pressure - Google Patents

Abstract

PURPOSE:To prevent a measured pressure from being outputted from an excessive-pressure protection mechanism and inputted to the main body of a differential pressure sensor when an excessive pressure is applied, and to obtain a measuring device which is excellent in a hysteresis characteristic due to the excessive pressure and can be made small in size, by constructing the device so that a silicon diaphragm of the protection mechanism comes into contact with the wall of an output chamber at that time. CONSTITUTION:An excessive-pressure protection mechanism 40 is constructed of a protecting main body 41, an internal chamber 42, a silicon diaphragm 43, an input chamber 44 and an output chamber 45. The diaphragm 43 partitions the internal chamber 42 into the input chamber 44 and the output chamber 45. When pressures P1 and P2 to be measured are applied from the left and the right of a body 50 of the main body, a measuring diaphragm 31 is displaced due to a differential pressure of the pressures P1 - P2. With the displacement of the diaphragm 31, an electric signal output corresponding to the differential pressure is obtained from a piezo-resistance element 35. In the case when an excessive pressure is applied, the diaphragm 43 comes into contact with the wall of the output chamber 45 and thereby it is prevented that a measured pressure is outputted from the protection mechanism 40 and inputted to the main body 30 of a differential pressure sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor differential pressure measuring device that has good hysteresis characteristics due to excessive pressure and can be made compact.

2. Prior Art> FIG. 5 is a diagram illustrating the configuration of a conventional example that has been commonly used.

In the figure, l is a block-shaped main body made of metal.

2 is an internal chamber provided in the main body 1.

3 is a measurement tire aphram which divides the internal chamber 2 into two measurement chambers 4.5 and functions as a moving electrode.

Fixed electrodes 6 and 7 are respectively provided on the wall of the internal chamber 2 facing the measurement tire aphram 3 via insulating materials 8 and 9.

Reference numerals 11 and 12 denote wave-shaped sill diaphragms that are provided on both outer surfaces of the main body 1 and constitute seal chambers 13 and 14 with the main body 1.

15 and 16 are the main body 1 facing the seal diaphragm 12.
It is a wavy pack-up nest installed on the side of the

Reference numerals 17 and 18 are communication holes that communicate the seal chambers 13 and 14 with the measurement chamber 45.

Reference numeral 19.21 denotes an incompressible sealed liquid filled in two chambers each consisting of a measurement chamber 4.5, a communication hole 17.18, and a seal chamber 13.14.

In this case, silicone oil is used.

In the above disaster warning, when measuring pressures P+ and P2 are applied from the left and right sides of the diagram of this f*1, the measuring diaphragm 3 is displaced by the differential pressure between the measuring pressures p and -p2; The capacitance between the voltage i6.7 and the measurement diaphragm 3 changes differentially, and an electrical signal output corresponding to the differential pressure is obtained.

Problems to be Solved by the Invention> However, in such a device, when excessive pressure is applied, Avoid applying pressure to the sensor part.

(2) There is a method in which the measuring tire flammable 3 is seated in contact with the opposing surface.

However, in the method (1), since the seal tire phragm 11.12 is brought into contact with the backing nest 15.16, a large amount of hysteresis occurs. The dimensions inevitably become larger.

In the method (2), the measurement tire flamm 3 is directly damaged, so the manufacturing cost of the opposing surface inevitably increases by 1~.

The present invention solves this problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor differential pressure measuring device that has good hysteresis characteristics due to excessive pressure and can be downsized.

Means for Solving the Problems> In order to achieve this object, the present invention provides a method in which a first measurement pressure is applied to a first measurement chamber provided on one side of a measurement tire phragm made of a silicone material. In a semiconductor differential pressure measuring device in which a second constant pressure is applied to a second measuring chamber provided on the other side and a differential pressure is measured, at least one of the first measuring chamber or the second measuring chamber is A block-shaped protective body made of a crow and connected to one side, an internal chamber provided in the protective body, an input chamber into which measurement pressure is input, and the first measuring chamber or the second measuring chamber. This semiconductor differential pressure measuring device is characterized in that it is equipped with an overpressure protection mechanism consisting of an output chamber that communicates with a measurement chamber and outputs measurement pressure, and a silicon diaphragm that separates the output chamber.

Effects> In the above configuration, when measurement pressure is applied from the left and right sides of the main body, the measurement diaphragm 3 is displaced due to the differential pressure between the measurement pressures. The displacement of the measuring tire flammable provides an electrical signal output corresponding to the differential pressure.

If excessive pressure is applied, it will contact the silicon tire phragm of the overpressure protection mechanism or the wall of the output chamber, preventing the measured pressure from being output from the overpressure protection mechanism and input to the differential pressure sensor 4 main body. Stop.

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

Example FIG. 1 is an explanatory diagram of the main part of an embodiment of the present invention.

In the figure, 30 is a silicon tire phragm 31, a first measurement chamber 33,
This is a differential pressure sensor body consisting of a piezoresistive element 35 and a second measurement chamber 36.

In this case, the silicon tire phragm 31 is formed in the first silicon substrate 32 by a recess 34 that is provided in the first silicon substrate 32 and extends across the first measurement chamber 33 .

The piezoresistive element 35 is provided on the silicon diaphragm 31.

A first measurement pressure P is applied to the first measurement chamber 33.

The second measurement chamber 36 is provided on the other side of the diaphragm 31, is made of glass material, and is provided with a ring-shaped spacer 37.
and a second substrate 38, and a second measurement pressure P2
or can be added.

40 is an overpressure protection mechanism provided in communication with the first measurement chamber 33 or the second measurement chamber 36.
, silicon diaphragm 43, input chamber 44, output chamber 45
It consists of

The protective body 41 is made of a block-shaped crow.

The internal chamber 42 is provided within the protective body 41.

The silicon diaphragm 43 divides the internal chamber 42 into an input chamber 44 into which the measured pressure is input and an output chamber 45 which is communicated with the first measurement chamber 33 or the second measurement chamber 36 and outputs the measured pressure.

Reference numeral 50 denotes a main body that houses the differential pressure sensor main body 30 and the overpressure retention M1a structure 40.

Reference numerals 51 and 52 designate seal tyres, which are provided on the surface of the main body 50 and form seal chambers 53 and 54 with the main body 50.

Note that the main body 50 may of course be omitted.

Further, in this case, anodic bonding is used between the silicon plate and the glass plate, and between the glass plate and the metal material, but low melting point glass bonding or the like may also be used, as long as it can be bonded.

61 is a communication hole that communicates the seal chamber 53 and the input chamber 44.

62 is a communication hole through which the output chamber 45 and the second measurement chamber 36 are communicated.

63 is a communication hole that communicates the first measurement chamber 33 and the output chamber 45.

64 is a communication hole that communicates the input chamber 44 and the seal chamber 54.

101, 102, 103, 104 are seal chambers 53, 54
, input chamber 44, output chamber 45, first and second measurement chambers 33.3
6. It is a sealed liquid that fills four chambers composed of communication holes 61, 62, 63, and 64. In this case, silicone oil is used.

In the above configuration, when measurement pressures PI and P2 are applied from the left and right sides of the main body pod 50 in the figure, the measurement tire flamm 31 is displaced by the differential pressure between the measurement pressures p and -p2. By the displacement of the measurement tire flammable 31, an electric signal output corresponding to the differential pressure can be obtained from the piezoresistive element 35. If excessive pressure is applied, the silicone tire flammable 43 of the overpressure protector'#I40 Contacting the wall prevents the measured pressure from being output from the overpressure protection mechanism 40 and input to the differential pressure sensor main body 30.

As a result, (1) the silicone tire flammable 43 is seated on the glass wall of the output chamber 45, and excessive pressure is applied to the differential pressure sensor main body 30.
Therefore, the hysteresis due to overpressure can be reduced compared to an overpressure protection mechanism using a metal diaphragm. According to experiments,
In the case of 150% overrange, it was about 0.02% for the overpressure protection mechanism using a silicon diaphragm, and about 0.1% for the overpressure protection mechanism using a metal tire phragm.

(2) Since silicon microfabrication technology can be used, the entire device can be made extremely compact.

(3) Since the overpressure protector side 40 is of simple construction, it requires less connecting pipes and sealed liquid, and has good temperature characteristics.

FIGS. 2, 3, and 4 are explanatory views of the structure of other embodiments of the present invention.

In this embodiment, when excessive pressure acts only on one side, an overpressure protection mechanism is provided only on the side on which excessive pressure acts.

<Effects of the Invention> As explained above, in the present invention, the first measurement pressure is applied to the first measurement chamber provided on one side of the measurement tire phragm made of a silicon material, and the first measurement pressure is applied to the other side of the measurement tire phragm made of a silicon material. In a semiconductor differential pressure measurement device in which a second measurement pressure is applied to a second measurement chamber provided to measure a differential pressure, the device is connected to at least one of the first measurement chamber or the second measurement chamber. A block-shaped protection body made of a crow, an internal chamber provided in the protection body, and the internal chamber communicated with an input chamber into which measurement pressure is input and the first measurement chamber or the second measurement chamber for measurement. A semiconductor differential pressure measuring device is constructed, characterized in that it is equipped with an overpressure protection mechanism consisting of an output chamber from which pressure is output and a silicon diaphragm that separates the device into an output chamber.

As a result, (1) By sitting on the silicon tire flamm 43 or the glass wall of the output chamber 45, the differential pressure sensor main body 30
Therefore, the hysteresis due to overpressure is reduced compared to an overpressure protection mechanism using a metal diaphragm. According to experiments,
In the case of 150% overrange, the overpressure protection mechanism using a silicon diaphragm will reduce the range by about 0.02%.
In the case of an overpressure protection mechanism using a metal diaphragm, it was about 0.1%.

(2) Since silicon microfabrication technology can be used, the entire device can be made extremely compact.

(3) Since the overpressure protector WJ40 has a simple structure, it does not require connecting pipes, etc., and requires less liquid to be filled, so it has good temperature characteristics.

Therefore, according to the present invention, it is possible to realize a semiconductor differential pressure measuring device that has good hysteresis characteristics due to excessive pressure and can be downsized.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the main parts of an embodiment of the present invention, Fig. 2,
FIGS. 3 and 4 are structural diagrams of essential parts of other embodiments of the present invention, and FIG. 5 is a structural diagram of a conventional example that has been commonly used. 30... Differential pressure sensor main body, 31... Silicon tire phragm, 32... First silicon substrate, 33... First measurement chamber, 34... Concave portion, 35... Piezoresistance element, 36... Second measurement chamber, 37... Spacer, 3
8... Second silicon substrate, 40... Overpressure protector frame, 41... Protection main body, 42... Internal chamber, 43...
・Silicon diaphragm, 44...Input chamber, 50...
・Wooden body, 51, 52...Seal diaphragm,
53.54...Sill room, 61,62,63.64...
-Communication hole, 1011 1 2 1, 102, 103, 104...Filled liquid.

Claims (1)

[Claims] A first measurement pressure is applied to a first measurement chamber provided on one side of a measurement diaphragm made of a silicon material, and a first measurement pressure is applied to a second measurement chamber provided on the other side. In a semiconductor differential pressure measurement device in which a second measurement pressure is applied and a differential pressure is measured, a block-shaped protective body made of glass is provided connected to at least one of the first measurement chamber or the second measurement chamber. and an internal chamber provided in the protective main body, and the internal chamber is divided into an input chamber into which measured pressure is input, and an output chamber which is communicated with the first measurement chamber or the second measurement chamber and outputs the measured pressure. A semiconductor differential pressure measuring device characterized by being equipped with an overpressure protection mechanism consisting of a silicon diaphragm that separates the pressure.