JPH09189629A - Absolute pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the influence of distortion due to the fixing of a sensor main body to a support by supporting the sensor main body on the support by means of a bonding wire without direct contact between them. SOLUTION: A bonding wire 22 is secured to the signal sampling pin 24 of a pressure vessel 21 at one end 23 and to an absolute pressure sensor main body 25 at the other end 26. One side 27 of the sensor main body 25 is temporarily locked to the pressure vessel 21 by a temporary locking member. On removal of the temporary locking member, the restoring force of the bonding wire 22 forms a gap 28 between one side 27 of the sensor main body 25 and the pressure vessel 21 such that they are not brought into contact by external vibrations. Thus the sensor main body can be supported on the pressure vessel by means of the bonding wire without making direct contact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention eliminates the influence of fixed strain due to the fixing of an absolute pressure sensor body to a support, makes it less susceptible to disturbance noise, and improves noise resistance.
In addition, the present invention relates to an inexpensive absolute pressure sensor.

[0002]

2. Description of the Related Art FIG. 6 is an explanatory view of the configuration of a conventional example which is generally used in the past.
No. in the official gazette. In the figure, 1 is a sensor chip. In this case, silicon is used.

[0003] Reference numeral 2 denotes a concave portion provided on the sensor chip 1 and constituting a diaphragm 3 serving as a strain generating portion of the sensor chip 1. Reference numeral 4 is a semiconductor pressure detecting element provided in the strain-flexing portion 3 of the sensor chip 1. Reference numeral 5 is a glass supporting substrate made of Pyrex glass, which is connected to one surface of the sensor chip and constitutes the recess and the pressure introducing chamber 6. In this case, the sensor chip 1 is bonded by anodic bonding or the like.

Reference numeral 7 is a communication hole provided in the glass supporting substrate and communicating with the pressure introducing chamber 6. Reference numeral 8 is a pressure vessel. The other surface of the glass support substrate 5 is joined. Reference numeral 9 is a bonding wire that electrically connects the signal extracting pin 11 provided on the pressure container and the semiconductor pressure detecting element 4.

In the above structure, the pressure introducing chamber 6 is evacuated.
P₀And the measured pressure Pm from the outside of the diaphragm 3
When applied, the diaphragm 3 is displaced by the measured pressure Pm.
You. This displacement is electrically detected by the semiconductor pressure detecting element 4.
Output, an electrical signal output corresponding to the measured pressure Pm is obtained.
It is.

[0006]

However, in such a device, the sensor chip 1 is bonded to the glass supporting substrate 5. As shown in FIG. 7, when the sensor chip 1 is directly adhered to the metal pressure vessel 8 or the like using the adhesive 12 or the like, a large stress is generated in the sensor chip 1 due to the temperature due to the difference in thermal expansion between the metal and silicon. . Further, the adhesive 12 is unstable and causes hysteresis and drift.

Therefore, in general, as shown in FIG.
A glass support substrate 5 of Pyrex glass or the like is interposed between the sensor chip 1 and the metal, and they are bonded by anodic bonding. The Pyrex glass serves as a cushioning material so that a large stress is not applied to the sensor chip 1.

However, since such a device interposes the glass support substrate 5 of Pyrex glass, the material cost,
The man-hours such as assembling man-hours are required and the cost is increased. Furthermore, as the sensor chip 1 becomes smaller, as in recent years, the difficulty of the work of joining itself increases.

The present invention solves this problem. An object of the present invention is to eliminate the influence of fixed strain due to the fixing of the absolute pressure sensor main body to the support body, make it less susceptible to the influence of disturbance noise, improve the noise resistance characteristics, and provide an inexpensive absolute pressure sensor. To provide.

[0010]

In order to achieve this object, the present invention is configured as follows. (1) Support, a plurality of bonding wires having one end fixed to the support, the other end of the bonding wire is fixed, and one surface is temporarily fixed to the support with a temporary fixing material, and the temporary fixing material is removed. By the restoring force of the bonding wire, an absolute pressure sensor main body is configured so that a gap is formed between the one surface and the support body to the extent that they are not in contact with each other due to external vibration. is there. (2) The absolute pressure sensor according to claim 1, wherein the absolute pressure sensor main body has a volume of approximately 1 mm ³ or less.

[0011]

With the above structure, the device of the present invention is manufactured as follows. One surface of the absolute pressure sensor main body is temporarily fixed to the support by a temporary fixing material. The bonding wire is used to wire bond the absolute pressure sensor body and the support.

The temporary fixing material is removed using a solvent or the like.
In the absolute pressure sensor main body, due to the restoring force of the bonding wire, a gap is formed between one surface of the absolute pressure sensor main body and the support body to the extent that they are not in contact with each other due to external vibration.

Since the absolute pressure sensor main body is supported by the bonding wire without directly contacting the supporting body, there is a possibility that the fixing strain of the absolute pressure sensor main body is fixed to the supporting body. Few. Moreover, the influence of mechanical disturbance is unlikely to reach the absolute pressure sensor body. Hereinafter, detailed description will be given based on examples.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a main part of an embodiment of the present invention. 2 is a plan view of an essential part of FIG. 1, and FIG. 3 is FIG.
3 is a detailed view of the absolute pressure sensor body of FIG. In the figure, FIG.
The configurations of the same symbols as and represent the same functions. Hereinafter, only differences from FIG. 6 will be described.

Reference numeral 21 is a support. In this case, a pressure vessel is used. 22 is one end 2 of the pressure vessel 21
3 is a plurality of fixed bonding wires. In this case, one end 23 of the bonding wire 22 is fixed to the signal extraction pin 24 of the pressure vessel 21.

25 is the other end 2 of the bonding wire 22.
6 is fixed, one surface 27 is temporarily fixed to the pressure vessel 21 by a temporary fixing material, and the removal of the temporary fixing material causes the restoring force of the bonding wire 22 to make contact between the one surface 27 and the pressure vessel 21 by external vibration. This is the absolute pressure sensor main body in which a gap 28 that does not occur is formed.

In this case, in the absolute pressure sensor main body 25, as shown in FIG. 3, a silicon sensor chip 31 is provided with an internal space 33 for forming a diaphragm 32.
The inner space 33 is kept in a vacuum. Diaphragm 32
A piezoresistive element 34 for detecting pressure is provided in the.

As an actual example, the absolute pressure sensor main body 25 uses 1 mm ³ or less and seven bonding wires made of gold or aluminum having a diameter of 50 μm or less. In the above configuration, when the measurement pressure Pm is applied to the absolute pressure sensor body 25, the diaphragm 32 is displaced. If this displacement is electrically detected by the piezoresistive element 34, the measured pressure P
An electric signal output corresponding to m is obtained.

Since the absolute pressure sensor main body 25 is supported by the bonding wire 22 without directly contacting the pressure container 21, a fixed strain due to the fixation of the absolute pressure sensor main body 25 to the pressure container 21. Less likely to be affected. Further, the influence of mechanical disturbance is unlikely to reach the absolute pressure sensor body 25.

Further, the absolute pressure sensor main body 25 has a measuring pressure P
Since it is surrounded by m, the measured pressure Pm is applied in a balanced manner. As in the case of the conventional example, the measured pressure is applied from one side, and the absolute pressure sensor body has a structure to prevent it from being deformed to one side. There is no need to make various efforts.

Furthermore, since the absolute pressure sensor main body 25 is supported by the bonding wire 22 in the pressure vessel 21, it can be manufactured at low cost. In particular, if a resist is used, a general semiconductor manufacturing process can be used and the cost can be further reduced.

Next, the device of the present invention is manufactured as follows, as shown in FIG. (1) As shown in FIG. 4A, one surface 27 of the absolute pressure sensor main body 25 is temporarily fixed to the pressure vessel 21 by the temporary fixing material 41. In this case, a resist is used. (2) As shown in FIG.
Is used to wire-bond the absolute pressure sensor body 25 and the pressure vessel 21.

(3) As shown in FIG. 4C, the temporary fixing material 41 is removed using a solvent or the like. Absolute pressure sensor body 2
In No. 5, due to the restoring force of the bonding wire 22, a gap 28 is formed between the one surface 27 of the absolute pressure sensor main body 25 and the pressure vessel 21 to the extent that they are not in contact with each other due to external vibration. The gap 28 is to be secured in advance by calculating the restoring force of the bonding wire 22.

As a result, the linear distortion characteristic is improved by eliminating the influence of the fixed distortion due to the fixing of the sensor chip, the noise resistance characteristic is improved by being less affected by the disturbance noise, and the semiconductor pressure gauge is inexpensive. Is obtained.

FIG. 5 is an explanatory view of the essential structure of another embodiment of the present invention. In this embodiment, the pressure vessel 21 is filled with a semi-fluid body 51 such as gel, and the absolute pressure sensor main body 25
Is gently fixed to the pressure vessel 21. It can handle severe vibrations and ensure reliability.

In the above-mentioned embodiments, the temporary fixing material 41 is described as a resist, but the present invention is not limited to this, and an adhesive may be used, for example. In short, it is sufficient that the absolute pressure sensor main body 25 can be temporarily fixed to the pressure vessel 21 and can be removed later.

[0027]

As described in detail above, the present invention provides
Since the absolute pressure sensor main body is supported by the bonding wire without directly contacting the support body, there is less possibility that the fixing strain due to the fixation of the absolute pressure sensor main body to the support body occurs. Moreover, the influence of mechanical disturbance is unlikely to reach the absolute pressure sensor body.

Further, since the absolute pressure sensor main body is surrounded by the measurement pressure, the measurement pressure is applied in a balanced manner, and the measurement pressure is applied from one side as in the case of the conventional example, and the absolute pressure sensor main body is offset. There is no need to make any struggles with the structure in order to prevent deformation.

Furthermore, the absolute pressure sensor main body is attached to the support,
Since the structure is supported by the bonding wire, it can be manufactured at low cost. In particular, if a resist is used, a general semiconductor manufacturing process can be used and the cost can be further reduced.

As a result, the influence of the fixed strain due to the fixing of the absolute pressure sensor main body to the support is eliminated, the influence of disturbance noise is reduced, the noise resistance is improved, and the inexpensive absolute pressure sensor is provided. can get.

[Brief description of the drawings]

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

FIG. 2 is a plan view of a main part of FIG.

FIG. 3 is a detailed explanatory diagram of an absolute pressure sensor body 15.

FIG. 4 is a production explanatory view of the present invention.

FIG. 5 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

FIG. 6 is an explanatory diagram of a configuration of a conventional example generally used in the related art.

FIG. 7 is an explanatory diagram of a configuration of a conventional example generally used in the related art.

[Explanation of symbols]

 21 Pressure Vessel 22 Bonding Wire 23 One End 24 Signal Extraction Pin 25 Absolute Pressure Sensor Body 26 Other End 27 One Side 28 Gap 31 Sensor Chip 32 Diaphragm 33 Internal Void 34 Piezoresistive Element 41 Temporary Fixing Material 51 Semi-fluid

Claims (2)

[Claims] 1. A support, a plurality of bonding wires having one end fixed to the support, the other end of the bonding wire being fixed, and one surface thereof temporarily fixed to the support by a temporary fixing material. The absolute pressure sensor main body is configured such that the removal force of the bonding wire creates a gap between the one surface and the support body to the extent that they are not in contact with each other due to external vibration. 2. The absolute pressure sensor according to claim 1, wherein the absolute pressure sensor main body has a volume of about 1 mm ³ or less.