JP2000183365A - Semiconductor pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor pressure sensor, that prevents vibration of a pressure receiving diaphragm caused by a higher-order vibration mode, and reduction of the potential energy of a vibrator. SOLUTION: In a semiconductor sensor that provides a recessed part 11 on a silicon substrate 10, forms a pressure receiving diaphragm 12, detects the strain in the pressure receiving diaphragm 12 by a vibrator 13, and measures the pressure applied to the pressure receiving diaphragm 12, at least two lead-in holes 14 and a plurality of chambers are provided. The lead-in holes 14 are provided in the pressure receiving diaphragm 12, and one end is connected to the recessed part 11. The chambers are connected to the other end of at least two lead-in holes 14 and are provided between the recessed part 11 of the pressure receiving diaphragm 12 and a vibrator 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration type semiconductor pressure sensor made of silicon, and more particularly to a semiconductor pressure sensor which prevents damping of a higher order vibration of a silicon diaphragm.

[0002]

2. Description of the Related Art FIG. 3 is an explanatory view of the configuration of a conventional semiconductor pressure sensor in which a diaphragm that generates distortion due to pressure and a vibrator that detects this distortion are provided on a silicon substrate. In the figure, a concave portion 2 is formed in a silicon substrate 1, a vibrator 3 is formed, and a pressure receiving diaphragm 4 is formed.

The strain of the pressure receiving diaphragm 4 is detected by the vibrator 3, and the pressure applied to the pressure receiving diaphragm 4 is
Measure P. However, in such a semiconductor pressure sensor, when the resonance frequency of the vibrator 3 changes due to the pressure P and approaches the natural frequency of the pressure receiving diaphragm 4 in which the vibrator 3 is embedded, the pressure receiving diaphragm 4 When the vibration starts, the potential energy of the vibrator 3 decreases, and the output decreases.

In order to prevent this problem, as shown in FIG. 4, a gap (about 30 μm) formed by the magnet 5 and the pressure receiving diaphragm 4 is filled with a high-viscosity oil 6 to attenuate the vibration of the pressure receiving diaphragm 4. I have. This utilizes the resistance when the oil 6 moves in the lateral direction.

[0005]

The semiconductor pressure sensor having such a damping structure overlaps with a higher-order vibration mode of the pressure receiving diaphragm when the excitation method of the vibrator is changed or the pressure receiving diaphragm is downsized. Innumerable antinodes of vibration as shown in FIG.

[0006] For this reason, there is no effect on higher-order vibration modes. This is thought to be due to the movement of the oil only between the neighboring belly and the nodes and the low oil resistance.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a concave portion and an introduction hole through which oil can move in a pressure receiving diaphragm, and a small chamber connected to the introduction hole. This makes it easier for the oil to move in the lateral direction.

Accordingly, it is an object of the present invention to provide a semiconductor pressure sensor in which the pressure receiving diaphragm does not vibrate in a higher-order vibration mode and the potential energy of the vibrator does not decrease.

[0009]

In order to achieve the above object, according to the present invention, in the semiconductor pressure sensor of the first aspect, a pressure receiving diaphragm is formed by providing a concave portion in a silicon substrate, and the pressure receiving diaphragm is formed. In a semiconductor pressure sensor for measuring a pressure applied to a pressure-receiving diaphragm by detecting a strain with a vibrator, at least two or more introduction holes provided at the pressure-receiving diaphragm and having one end connected to the recess, and at least two or more introduction holes. A plurality of chambers respectively connected to the other end and provided between the concave portion of the pressure receiving diaphragm and the vibrator are provided.

As a result, the pressure receiving diaphragm is provided with a concave portion and an introduction hole through which oil can move, and a small chamber connected to the introduction hole is provided to facilitate the lateral movement of oil. Even in the higher-order vibration mode, vibration of the pressure receiving diaphragm can be prevented, and a semiconductor pressure sensor can be obtained in which the potential energy of the vibrator does not decrease and the output does not decrease.

According to a second aspect of the present invention, in the semiconductor pressure sensor according to the first aspect, oil is sealed in the recess, the introduction hole, and the chamber.

As a result, the oil is sealed in the concave portion, the introduction hole and the chamber, so that a greater damping effect can be obtained.
Even in the higher-order vibration mode, the vibration of the pressure receiving diaphragm can be further prevented, and a semiconductor pressure sensor can be obtained in which the potential energy of the vibrator does not decrease and the output does not decrease.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory diagram of a main configuration of an embodiment of the present invention.

In the figure, a recess 11 is formed in a silicon substrate 10.
Is provided to form the pressure receiving diaphragm 12.

In the pressure receiving diaphragm 12 between the recess 11 and the vibrator 13, a plurality of introduction holes 14 having a small diameter are provided, and a chamber 15 to which two or more introduction holes 14 are connected is provided. A damping unit 16 is arranged.

The recess 11 and the damping unit 16 have
Oil 17 is filled. The damping unit 16
It has the shape shown in FIG. 2, and the size is made to correspond to the area A (see FIG. 5) of the antinode of vibration.

Accordingly, the oil 1 in high-order vibration
The movement of 7 is performed through the oil introduction hole 14 in the damping unit 16 immediately below the vibration valley or peak, and a greater resistance is obtained than the movement between the abdominal nodes.

As a result, the concave portion 1 is formed in the pressure receiving diaphragm 12.
1 and an introduction hole 14 through which the oil 17 can move, and a small chamber 15 connected to the introduction hole 14 is provided.
The movement of the oil 17 in the horizontal direction is made easy to occur. Even in a higher-order vibration mode, the vibration of the pressure receiving diaphragm 12 can be prevented, and the potential energy of the vibrator 13 is reduced to lower the output. A semiconductor pressure sensor that does not have any problem is obtained.

Further, since the oil 17 is sealed in the concave portion 11, the introduction hole 14, and the chamber 15, a greater damping effect is obtained, and the vibration of the pressure receiving diaphragm 12 can be further prevented even in a higher-order vibration mode. A semiconductor pressure sensor is obtained in which the potential energy of the element 13 does not decrease and the output does not decrease.

[0020]

As described above in detail, according to the semiconductor pressure sensor of the first aspect of the present invention, the pressure receiving diaphragm is provided with the concave portion and the introduction hole through which the oil can move, and is connected to the introduction hole. A small chamber is provided to make it easier for the oil to move in the horizontal direction.The vibration of the pressure receiving diaphragm can be prevented even in the higher-order vibration mode, and the potential energy of the vibrator decreases and the output decreases. A semiconductor pressure sensor that does not end up being obtained.

According to the semiconductor pressure sensor of the second aspect of the present invention, the following effects can be obtained. Oil is sealed in the recess, introduction hole and chamber, so a greater damping effect can be obtained, and even in higher-order vibration modes, vibration of the pressure receiving diaphragm can be further prevented, and the potential energy of the vibrator is reduced and output is reduced. A semiconductor pressure sensor that does not lower can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing one embodiment of a semiconductor pressure sensor of the present invention.

FIG. 2 is an explanatory diagram of a main part configuration showing a damping unit which is a main part of the present invention.

FIG. 3 is an explanatory diagram showing a configuration of a conventional semiconductor pressure sensor.

FIG. 4 is an explanatory view showing an entire configuration of a main part of a conventional semiconductor pressure sensor.

FIG. 5 is an explanatory diagram showing higher-order vibration of a conventional semiconductor pressure sensor.

[Explanation of symbols]

 Reference Signs List 10 silicon substrate 11 concave portion 12 pressure receiving diaphragm 13 vibrator 14 introduction hole 15 chamber 16 damping unit 17 oil

Claims (2)

[Claims] 1. A semiconductor pressure sensor for forming a pressure receiving diaphragm by providing a concave portion in a silicon substrate, detecting a strain of the pressure receiving diaphragm by a vibrator, and measuring a pressure applied to the pressure receiving diaphragm, wherein one end provided on the pressure receiving diaphragm is provided. At least two or more introduction holes connected to the recess, and a plurality of chambers respectively connected to the other ends of the at least two or more introduction holes and provided between the recess and the vibrator of the pressure receiving diaphragm. A semiconductor pressure sensor, comprising: 2. The semiconductor pressure sensor according to claim 1, wherein oil is sealed in said recess, said introduction hole and said chamber.