JP2000105161A - Pressure detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure detector which prevents invasion of dust, mote or the like and never directly receives external light. SOLUTION: A semiconductor pressure sensor chip 1 detects a pressure of a fluid. A base plate 2 has the semiconductor pressure sensor chip 1 arranged thereto. A cover body 3 unites with the base plate 2, thereby forming a storing part R for storing the semiconductor pressure sensor chip 1. An atmospheric pressure introduction hole 8 is formed near a unite part of the base plate 2 to the cover body 3 at the side of the storing part R to connect internal and external airs of the storing part R.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure detector for detecting a pressure of a fluid such as a gas or a liquid by a semiconductor pressure sensor chip, and more particularly to a pressure detector for detecting a difference between a reference pressure of the atmosphere and a pressure of the fluid. It relates to a detector.

[0002]

2. Description of the Related Art As a conventional pressure detector, a semiconductor pressure sensor chip formed by anodically bonding a diaphragm having a semiconductor strain gauge formed on a glass pedestal is disposed on a metal base plate. There is one that covers the periphery of the sensor chip with a metal cover (see, for example,
See, for example, JP-A-31533 and JP-A-6-151894.

The pressure detector is disposed on the back side of the base plate, and transmits a pressure of a fluid to the semiconductor pressure sensor chip. The pressure detector introduces atmospheric pressure to the upper surface of the cover. An atmospheric pressure introducing hole is provided, and a difference between a reference pressure based on the atmospheric pressure and a pressure based on the fluid is detected by the semiconductor pressure sensor chip.

[0004]

In the above-described pressure detector, the pressure introducing port and the lead pin electrically connected to the semiconductor pressure sensor chip are formed from a glass material (insulating material) on the back side of the base plate. A structure in which the sealing members are hermetically joined by a sealing member is adopted. In such a pressure detector, the atmospheric pressure introducing hole is generally provided on an upper surface of the cover body located above the semiconductor pressure sensor chip. By providing the atmospheric pressure introduction hole on the upper surface of the cover body as described above, dust and dust easily enter from the atmospheric pressure introduction hole, and the reliability in electrical connection of the semiconductor pressure sensor chip is reduced. There is a problem that it is. Further, when the pressure detector is used under the condition of directly receiving external light, if an atmospheric pressure introduction hole is formed on the upper surface of the cover body, the pressure is incident from the atmospheric pressure introduction hole. Since the external light irradiates the semiconductor pressure sensor chip, there is a problem that the output characteristics of the semiconductor pressure sensor chip made of a semiconductor material are changed.

Accordingly, the present invention is directed to the above problems and provides a pressure detector which prevents intrusion of dust and dirt and does not receive external light directly.

[0006]

In order to solve the above-mentioned problems, the present invention provides a semiconductor pressure sensor chip for detecting a pressure of a fluid, a base plate on which the semiconductor pressure sensor chip is provided, and a joint with the base plate. And a cover body forming a storage section for storing the semiconductor pressure sensor chip, and formed near the storage section side of a joint portion of the base plate with the cover body, and the inside air and the outside air of the storage section. And an atmospheric pressure introduction hole communicating with

In addition, a semiconductor pressure sensor chip for detecting a pressure of a fluid, a base plate on which the semiconductor pressure sensor chip is disposed, and a storage portion for receiving the semiconductor pressure sensor chip by being joined to the base plate are formed. A cover, a pressure introduction unit disposed on the back side of the base plate, for transmitting the pressure to the semiconductor pressure sensor chip, and electrically connected to the semiconductor pressure sensor chip; and a back side of the base plate. A sealing member for fixing the pressure introducing portion and the lead pin to the base plate; and a sealing member formed near the housing portion side of a joint portion of the base plate with the cover body, And an atmospheric pressure introduction hole for communicating the inside air and the outside air of the section.

A notch is formed in the peripheral edge of the base plate, and when the peripheral edge of the base plate is joined to the peripheral edge of the cover body, the joint portion between the base plate and the cover body is formed. The atmospheric pressure introduction hole is formed by a part of the notch located on the storage part side.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a semiconductor pressure sensor chip for detecting a pressure of a fluid on a base plate, and a cover body forming a storage portion for storing the semiconductor pressure sensor chip, and the base plate. And a pressure detector formed by joining the pressure sensors. Such a pressure detector forms an atmospheric pressure introduction hole which communicates the inside air and the outside air of the storage portion in the vicinity of the storage portion side of the joint portion of the base plate with the cover body. Therefore, since the atmospheric pressure introduction hole can be formed on the back surface side (the mounting surface side of the circuit board) of the base plate, intrusion of dust and dirt can be prevented, and reliability in electrical connection can be improved. it can. Since the semiconductor light sensor chip is not directly irradiated with external light, fluctuations in output characteristics can be suppressed.

Further, the present invention is particularly effective for a pressure detector provided with a reservoir for a sealing member for joining a pressure introduction port (pressure introduction section) and a lead pin on the back side of the base plate. In the pressure detector having such a configuration,
A notch is formed in the peripheral edge of the base plate, and when the peripheral edge of the base plate and the peripheral edge of the cover body are joined, the cutout portion is located on the storage portion side of the joint portion of the base plate with the cover body. The atmospheric pressure introduction hole is formed by a part of the notch. Therefore, if an atmospheric pressure introducing hole is to be provided exclusively on the back side of the base plate, it must be formed so as to avoid the reservoir, and the pressure detector becomes large, but the base plate and the cover By forming the atmospheric pressure introducing hole near the joint of the body, the atmospheric pressure introducing hole can be obtained without increasing the size of the pressure detector.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the accompanying drawings. FIG. 1 is a sectional view of a main part showing the entire structure of a pressure detector, FIG. 2 is a plan view showing a state where a semiconductor pressure sensor chip is arranged on a base plate, and FIG. 3 is a state of the pressure detector viewed from above. FIG. 4 is a plan view showing another embodiment.

1 to 3, a pressure detector includes a semiconductor pressure sensor chip 1 and a semiconductor pressure sensor chip 1.
, A cover body 3 joined to the base plate 2 to cover the periphery of the semiconductor pressure sensor chip 1, a pressure introduction port 4 for transmitting fluid pressure to the semiconductor pressure sensor chip 1, A lead pin 5 for inputting power to the semiconductor pressure sensor chip 1 and outputting a signal from the semiconductor pressure sensor chip 1, and a sealing for hermetically joining the pressure introducing port (pressure introducing portion) 4 and the lead pin 5 to the base plate 2. And a stop member 6.

The semiconductor pressure sensor chip 1 is formed by joining a thin diaphragm 1c on which a semiconductor strain gauge is formed on a glass pedestal 1b having a pressure introducing hole 1a by, for example, an anodic bonding method.

The base plate 2 comprises a semiconductor pressure sensor chip 1
And a metal material having a similar thermal expansion coefficient (for example, Kovar). The base plate 2 has a mounting portion 2a for disposing the semiconductor pressure sensor chip 1, and the mounting portion 2a has a hole 2b for transmitting pressure to the semiconductor pressure sensor chip 1. And a hole 2c for disposing the lead pin 5. Also, base plate 2
The first flange portion 2d is formed such that both end portions of the mounting portion 2a are bent downward (substantially vertically), and extend outward from the bent end portion.
The base plate 2 having the above-described configuration forms the reservoir 2e of the sealing member 6 on the back surface side.

The semiconductor pressure sensor chip 1 is formed on the surface of the glass pedestal 1b facing the mounting portion 2a such that the pressure introducing hole 1a of the glass pedestal 1b and the hole 2b of the mounting portion 2a face each other. It is disposed on the mounting portion 2a via a metallization layer (not shown), and is hermetically bonded to the base plate 2.

The cover body 3 is made of a metal material made of, for example, SPC and plated with nickel.
Corresponding to the first flange portion 2d, a second flange portion 3a for joining with the base plate 2 by, for example, welding is formed. The cover body 3 forms a housing part R for housing the semiconductor pressure sensor chip 1 by being joined to the base plate 2.

The pressure introduction port 4 is made of, for example, the same material as the base plate 2 and has a pressure introduction hole 4a for transmitting fluid pressure to the semiconductor pressure sensor chip 1.
The pressure introduction port 4 is disposed on the back surface of the base plate 2 such that the pressure introduction hole 4a and the hole 2b of the base plate 2 face each other. The pressure of the fluid is transmitted from the pressure introduction hole 4a to the semiconductor pressure sensor chip 1 via the hole 2b.

The lead pins 5 are made of, for example, the same material as the base plate 2, and perform power input to the semiconductor pressure sensor chip 1 and signal output from the semiconductor pressure sensor chip 1. The lead pins 5 are provided in holes 2c formed around the semiconductor pressure sensor chip 1 of the base plate 2, and are electrically connected to the semiconductor pressure sensor chip 1 by a connecting member 7 made of a conductive material such as gold or aluminum. (Wire bonding).

The sealing member 6 is made of a glass material having a thermal expansion coefficient close to that of the base plate 2 and the pressure introducing port 4 and the lead pin 5. 5 and the base plate 2 are hermetically bonded.

The most characteristic feature of the pressure detector of the present invention is that an atmospheric pressure introducing hole 8 is provided on the back surface of the base plate 2. The atmospheric pressure introducing hole 8 is formed by a notch 2f having a width W2 larger than the width W1 of the second flange 3a of the cover body 3 from the outer end of the first flange 2d of the base plate 2.
Are obtained. That is, when the base plate 2 and the cover body 3 are joined, due to the relationship of W2> W1, the joint portion (each flange portion) of the base plate 2 with the cover body 3 (the side of the semiconductor pressure sensor chip 1). ), A hole is formed by a part of the notch 2 f, and the hole forms an atmospheric pressure introduction hole 8 on the back surface side of the base plate 2, through which the inside air and the outside air of the storage portion R communicate. Will be. Therefore, the pressure detector detects a difference between the reference pressure P1 due to the atmospheric pressure introduced by the atmospheric pressure introducing hole 8 formed on the back side of the base plate 2 and the pressure P2 of the fluid.

Next, another embodiment will be described with reference to FIG. In the above-described embodiment, the atmospheric pressure introduction hole 8 is formed by the cutout portion 2f formed with a width of W2 from the outer end of the first flange portion 2d of the base plate 2.
Is provided with a notch hole (notch portion) 2g of a predetermined size in the first flange portion 2f of the base plate 2, and the base plate 2
By forming a hole by a part of the cutout hole 2g in the vicinity of the storage portion R side of the joint portion with the cover body 3,
The one that forms the atmospheric pressure introduction hole 9 is shown.

Such pressure detectors have atmospheric pressure introduction holes 8 and 9.
Can be provided on the back surface side of the base plate 2 by the above-described configuration. Therefore, compared with a conventional pressure detector in which an atmospheric pressure introduction hole is provided on the upper surface of a cover body located above the semiconductor pressure sensor chip 1, dusts And the intrusion of dust and the like can be prevented, improving the reliability of electrical connection,
Since the semiconductor light sensor chip 1 is not directly irradiated with external light, fluctuations in output characteristics can be suppressed.

When the atmospheric pressure introducing hole is provided exclusively on the back side of the base plate 2 of the pressure detector, it must be formed so as to avoid the reservoir 2e for filling the sealing member 6. There is a problem that the pressure detector becomes large. However, like the pressure detector of the present invention, the first
When a notch 2f or a notch hole 2g is formed in the flange 2d of the base plate 2 and the first flange 2d of the base plate 2 is joined to the second flange 3a of the cover 3,
Atmospheric pressure introduction holes 8 and 9 are formed on the back surface of the base plate 2 by a part of the notch 2f or the notch hole 2g located on the storage portion R side of the joint portion of the base plate 2 with the cover body 3. Therefore, the size of the pressure detector is not increased.

In this embodiment, the pressure detector in which the pressure introducing port 4 and the lead pin 5 are joined to the back surface of the base plate 2 by the sealing member 6 has been described as an example. The present invention may be applied to a pressure detector in which a base plate having no reservoir portion 2e of the sealing member 6 is used, and a pressure introduction port is joined by a brazing material, and a lead pin is joined by a sealing member made of a glass material.

[0025]

According to the present invention, there is provided a semiconductor pressure sensor chip for detecting the pressure of a fluid, a base plate on which the semiconductor pressure sensor chip is disposed, and a housing for housing the semiconductor pressure sensor chip by being joined to the base plate. A cover body forming a portion, and an atmospheric pressure introduction hole formed near the housing portion side of a joint portion of the base plate with the cover body and communicating between inside air and outside air of the housing portion. It is a pressure detector, and since the atmospheric pressure introduction hole can be formed on the back surface side of the base plate, intrusion of dust and dust can be prevented, and reliability in electrical connection can be improved. Since the light does not directly irradiate the semiconductor pressure sensor chip, fluctuations in output characteristics can be suppressed.

Further, a semiconductor pressure sensor chip for detecting a pressure of a fluid, a base plate on which the semiconductor pressure sensor chip is disposed, and a storage portion for receiving the semiconductor pressure sensor chip by being joined to the base plate are formed. A cover, a pressure introduction unit disposed on the back side of the base plate, for transmitting the pressure to the semiconductor pressure sensor chip, and electrically connected to the semiconductor pressure sensor chip; and a back side of the base plate. A sealing member for fixing the pressure introducing portion and the lead pin to the base plate; and a sealing member formed near the housing portion side of a joining portion of the base plate with the cover body, A pressure detector with an atmospheric pressure introduction hole that communicates the inside air and outside air of the unit, prevents dust and dirt from entering, and improves reliability in electrical connection. As well as being able to above, since the no external light is irradiated directly to the semiconductor pressure sensor chip, it is possible to suppress variations in output characteristics.

A notch is formed in the peripheral edge of the base plate, and when the peripheral edge of the base plate is joined to the peripheral edge of the cover body, a notch is formed at the joint between the base plate and the cover body. The atmospheric pressure introducing hole is formed by a part of the cutout portion located on the storage portion side, and the atmospheric pressure introducing hole can be obtained on the back side of the base plate without increasing the size of the pressure detector. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a pressure detector according to an embodiment of the present invention.

FIG. 2 is a plan view showing a state where the semiconductor pressure sensor chip of the embodiment is provided.

FIG. 3 is a plan view of the pressure detector of the embodiment.

FIG. 4 is a plan view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor pressure sensor chip 2 Base plate 2d 1st flange part 2f Notch part 2g Notch hole part (notch part) 3 Cover body 3a 2nd flange part 4 Pressure introduction port (pressure introduction part) 5 Lead pin 6 Sealing Stop member 8, 9 Atmospheric pressure introduction hole R Storage section

Claims (3)

[Claims] 1. A semiconductor pressure sensor chip for detecting a pressure of a fluid, a base plate on which the semiconductor pressure sensor chip is disposed, and a storage part for receiving the semiconductor pressure sensor chip by being joined to the base plate. A pressure detector, comprising: a cover body; and an atmospheric pressure introduction hole formed in proximity to the storage section side of a joint portion of the base plate with the cover body, and communicating inside air and outside air of the storage section. 2. A semiconductor pressure sensor chip for detecting a pressure of a fluid, a base plate on which the semiconductor pressure sensor chip is disposed, and a storage part for receiving the semiconductor pressure sensor chip by being joined to the base plate. A cover, a pressure introduction unit disposed on the back side of the base plate, for transmitting the pressure to the semiconductor pressure sensor chip, and electrically connected to the semiconductor pressure sensor chip; and a back side of the base plate. A sealing member for fixing the pressure introducing portion and the lead pin to the base plate; and a sealing member formed near the housing portion side of a joining portion of the base plate with the cover body, A pressure detector having an atmospheric pressure introduction hole communicating the inside air and the outside air of the section. 3. A notch portion is formed in a peripheral edge of the base plate, and when a peripheral edge of the base plate is joined to a peripheral edge of the cover body, a notch portion of a joint portion between the base plate and the cover body is formed. 3. The pressure detector according to claim 1, wherein the atmospheric pressure introduction hole is formed by a part of the notch located on the storage unit side. 4.