JPH0798257A - Pressure sensor - Google Patents

Abstract

PURPOSE:To improve detection precision with a leak in reference pressure prevented by providing a pressure introducing groove which communicates with a pressure introducing opening and the space in a housing. CONSTITUTION:Pressure P of a medium under measurement is guided from a pressure introducing groove 38, passing through a pressure introducing pipe 23 and provided from the pressure introducing opening 32 of a base 31 to a junction face to the base 31 of a pedestal 35, into the space 37 in a housing 36 and acts on the diaphragm pressure receiving side of the top face of a semiconductor pressure transducer 33, so that its output signal is extracted outside the housing 36 by a lead 39. Pressing acts on each junction face between an element 33 and the pedestal 35 and between the pedestal 35 and the base 31 with the result that no tensile stress occurs; therefore, strain is prevented from occurring, and a leak in reference pressure sealed in a hermetic space 34 formed by the element 33 and the pedestal 35 is suppressed. This causes no variation in output to improve detection precision.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor incorporating a semiconductor pressure conversion element.

[0002]

2. Description of the Related Art Conventionally, there are a reference pressure type and a differential pressure type as pressure sensors for controlling intake pressure of an engine. Of these two types, as shown in FIG. 4, the reference pressure type pressure sensor 20 has a semiconductor pressure conversion element 25 that outputs an output signal with respect to the pressure P of the medium to be measured, and the semiconductor pressure conversion element 25 mounted thereon. The pedestal 26 and the pedestal 27 on which they are mounted are eutectic-bonded to each other, and the back pressure side opposite to the pressure receiving side of the semiconductor pressure conversion element 25 is a space formed by the housing 21 and the pedestal 27 having no atmosphere release hole. The space 24 is sealed with a reference pressure of vacuum or constant pressure, and the base 27 has a pressure for guiding the pressure P of the medium to be measured to the diaphragm pressure receiving side of the semiconductor pressure conversion element 25. Braze the introduction pipe 23,
This is a structure in which an output signal of the semiconductor pressure conversion element 25 is taken out of the housing 21 by a conductor 22 penetrating the base 27. Further, the differential pressure type pressure sensor is one in which the atmospheric pressure is introduced into the housing 21 and the differential pressure between the pressure P and the atmospheric pressure is measured.

[0003]

In the structure of the conventional reference pressure type pressure sensor 20 described above, the diaphragm pressure receiving side of the semiconductor pressure converting element 25 for receiving the pressure P of the medium to be measured is joined to the pedestal 26. Is. Therefore, especially for high pressure, the semiconductor pressure converting element 25 is driven by the duty cycle of the pressure P of the medium to be measured which acts on the semiconductor pressure converting element 25.
The tensile stress is repeated in the peeling direction from the pedestal 26 and the pedestal 26 from the pedestal 27, respectively, and strain is generated, resulting in a large variation in output. Further, there is a problem that the reference pressure in the space 24 of the housing 21 leaks from the joint between the housing 21 and the base 27 or the base penetrating portion of the conductor 22.

For this reason, it is considered that the pressure P is introduced into the housing 21 from the upper portion of the housing 21 to seal the reference pressure in the pedestal to prevent the leakage and the fluctuation of the output. When the pressure is introduced from the upper part, there is a problem that the arrangement of the piping when mounting the pressure sensor and the arrangement of the processing circuit for processing the signal output from the pressure sensor must be changed.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and its characteristic constitution is to join a pedestal on which a semiconductor pressure converting element is mounted to a base having a pressure introducing port. Then, in a pressure sensor in which the semiconductor pressure converting element and the pedestal are enclosed in a housing joined to the base with a space, the semiconductor pressure converting element is sealed to a pedestal with a constant reference pressure. A pressure introducing groove that connects the pressure introducing port and the space inside the housing is provided on the joint surface of the pedestal to the base.

[0006]

With the above structure, the pressure of the medium to be measured, which has entered from the pressure introducing port of the base, is guided to the space in the housing through the pressure introducing groove provided in the joint surface of the base to the base, and the semiconductor pressure converting element is formed. Pressure acts on the diaphragm pressure receiving side of the
No tensile stress is generated in the joints between the semiconductor pressure conversion element and the pedestal and between the pedestal and the pedestal, and the pressure resistance is improved.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a pressure sensor 30 is a semiconductor pressure conversion element 33 that outputs an output signal with respect to a pressure P of a medium to be measured.
And a pedestal 35 on which the semiconductor pressure conversion element 33 is mounted
And a base 31 on which they are mounted are anodically bonded to each other, and a fixed reference pressure is sealed in a sealed space 34 formed by the semiconductor pressure conversion element 33 and the pedestal 35.

A pressure introducing port 32 is opened in the base 31, and a pressure introducing pipe 23 is brazed to the pressure introducing port 32. In addition, the base 31 has a housing 36 without an atmosphere release hole.
Are joined together with a space 37. Reference numeral 39 is a conductor wire that penetrates the base 31 to take out the output signal of the semiconductor pressure conversion element 33 to the outside of the housing 21.

A pressure introducing groove 38 is provided on the joint surface of the pedestal 35 to the base 31 so that the pressure introducing port 32 communicates with the space 37 in the housing 36. The pressure introducing groove 38 is formed in the base 31 of the pedestal 35 as shown in FIG.
A cross groove that opens to the lower side surface of the pedestal 35 is preferably formed on the lower surface side opposite to the surface to which the semiconductor pressure converting element 33 is placed and bonded. However, it is not limited to the cross groove.

Since the present invention is configured as described above, the pressure P of the medium to be measured passes through the pressure introducing pipe 23 and the base 3
The space 3 in the housing 36 from the pressure introduction groove 38 provided on the joint surface of the pedestal 35 from the pressure introduction port 32 of No. 1 to the base 31.
7, the pressure acts on the diaphragm pressure receiving side of the upper surface of the semiconductor pressure converting element 33, and the output signal is taken out of the housing 21 through the lead wire 39.

As described above, the pressure P of the medium to be measured introduced into the space 37 in the housing 36 through the pressure introducing groove 38 provided on the joint surface of the lower surface of the pedestal 35 to the base 31 is the pressure of the semiconductor pressure converting element 33. Since it acts on the diaphragm pressure receiving side of the upper surface, it acts to press against the semiconductor pressure conversion element 33 and the pedestal 35 and the joint portions of the pedestal 35 and the base 31 and no tensile stress is generated, so that distortion does not occur, Leakage of the reference pressure sealed in the sealed space 34 formed by the semiconductor pressure conversion element 33 and the pedestal 35 is suppressed, and fluctuations in output are eliminated.

In order to manufacture a sensor structure in which the semiconductor pressure conversion element 33 is placed and bonded on the pedestal 35, as shown in FIG. 3, a plurality of pedestals 35 having slits 35B for dividing each into a plurality of pedestals are used. On the upper surface of the pedestal material 35A with the continuous pressure introducing groove 38, a plurality of semiconductor pressure conversion elements 33 are provided at the same positions as the slits 35B, and the corresponding disconnection lines 3 are formed.
3, the semiconductor pressure converting element material 33A which is continuous is placed, and the semiconductor pressure converting element material 33A is connected to one side and the pedestal material 35A is connected to the other side in the vacuum container 40 in which the pressure is vacuumized by the vacuum pump 41. Then, by applying a voltage of about 900 V from the power source 42, the pedestal material 35A
And 33 A of semiconductor pressure conversion element materials are joined. Then, by cutting the slit 35B and the separating line 33, a single sensor structure is obtained. In this case, the reference pressures of the constant pressure in the sealed space 34 formed by the semiconductor pressure conversion element 33 and the pedestal 35 are all sealed to be the same, and the sensors can be made uniform.

[0013]

As described above, according to the present invention, the semiconductor pressure converting element is mounted on the pedestal by sealing the reference pressure of a constant pressure, and the pressure introducing port and the housing are provided on the joint surface of the pedestal to the base. Since there is a pressure introducing groove that communicates with the internal space and the pressure of the medium to be measured introduced into the space inside the housing is applied to the diaphragm pressure receiving side of the upper surface of the semiconductor pressure conversion element, distortion occurs. The leakage of the reference pressure sealed between the semiconductor pressure conversion element and the pedestal is suppressed, the fluctuation of the output is prevented, and the detection accuracy is improved. Further, the standard pressure type and the differential pressure type can be selectively used only in the pedestal shape in the same shape package, the pedestal joining area is small with respect to the package, and the strain transmitted to the semiconductor pressure conversion element on the pedestal is small.

[Brief description of drawings]

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

FIG. 2 is a perspective view of a main part showing an example of a pedestal used in the pressure sensor according to the present invention.

FIG. 3 is an explanatory view showing a manufacturing example of a sensor structure in which a semiconductor pressure conversion element is mounted and joined to a pedestal of a pressure sensor according to the present invention.

FIG. 4 is a sectional view of a conventional pressure sensor.

[Explanation of symbols]

 30 pressure sensor 31 base 32 pressure introduction port 33 semiconductor pressure conversion element 35 pedestal 36 housing 37 space 38 pressure introduction groove

Claims (1)

[Claims] 1. A pedestal on which a semiconductor pressure converting element is mounted is joined to a base having a pressure introducing port, and the semiconductor pressure converting element and the pedestal are enclosed in a housing joined to the base with a space. In the pressure sensor consisting of, the semiconductor pressure conversion element is mounted on a pedestal with a constant reference pressure sealed.
A pressure sensor characterized in that a pressure introducing groove for communicating the pressure introducing port and a space in the housing is provided on a joint surface of the pedestal to the base.