JPS61184435A - Semiconductor type pressure sensor - Google Patents

Abstract

PURPOSE:To hold good vacuum reference voltage and to prevent the titled sensor from scaling up, by adhering the side surface of a pedestal to a base through sealing glass while adhering a gauge part to the pedestal through a gold/silicon alloy material. CONSTITUTION:The side surface of a pedestal 5 is adhered and fixed to a base 1 through sealing glass 4 so as to cross the surface of said base 1 at right angles. The pedestal 5 and a gauge part 10 are fixed by a gold/silicon alloy material 8 and a lead pin 2 receives gold plating. A cover 3 is fixed to the base 1 under vacuum by welding to form a vacuum chamber 11. Therefore, the materials of the adhered parts are prevented from flowing out upon melting and the vacuum chamber 11 can always hold definite reference pressure and the bonding strength between the base 1 and the pedestal 5 is high and scaling-up can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention particularly relates to a semiconductor pressure sensor based on vacuum.

[Background of the invention]

As a semiconductor pressure sensor, the conventional Japanese Patent Application Laid-Open No. 52-1909
No. 1 is known. FIG. 3 is a sectional view of a conventional semiconductor pressure sensor. In the figure, 1 is a base, and 2 is a lead pin, which is sealed and fixed to the base 1 with an adhesive glass 4. Reference numeral 5 denotes a pedestal that protrudes inside the sensor and is fixed at one end to the base 1 through a brazing material 6. A gauge portion 10 of a semiconductor strain gauge is fixed to the other end through a brazing material 7.
0, pressure is transmitted to the sensor through a passage 12 as shown by the arrow. Reference numeral 9 connects the gauge portion 10 and the lead pin 2 with a thin gold wire. The gauge part 10, the thin gold wire 9, and the pedestal 5 are covered with a cover 3 and sealed and fixed to form a vacuum chamber 11.

Then, the pressure in the arrow P is detected using the pressure inside the vacuum chamber 11 as a reference pressure.

By the way, since the brazing materials 6 and 7 are made of solder material and flux is used, if organic substances in the flux remain between the base 1 and the pedestal 5, the flux residue may be deposited in the vacuum chamber 11 during use. There was a problem that the vacuum could not be maintained or the base 1 would corrode and the pedestal 5 would peel off from the base 1. In addition, since the pedestal 5 joined to the base 1 is surface-bonded with the brazing material 6, the pressure P
As the value increases, the contact area must be increased,
As a result, there was a drawback of increasing the size.

It is an object of the present invention to provide a semiconductor pressure sensor that can maintain a vacuum reference pressure in a vacuum chamber and prevent enlargement.

[Summary of the Invention] The semiconductor pressure sensor of the present invention includes a gauge portion fixed to a pedestal so as to sense pressure within the sensor, a base sealingly fixing the pedestal, and a sealing penetrating portion to the base. A lead pin is attached to the gauge part and has an end connected to the gauge part via a thin gold wire, and a cover is sealed and fixed to the base that covers the gauge part and the thin gold wire and forms a vacuum chamber, The pressure is detected using the indoor pressure as a reference pressure, and the pedestal is sealed and fixed to the base by a surface perpendicular to the base.

[Embodiments of the invention]

Hereinafter, an embodiment of the semiconductor pressure sensor of the present invention will be explained with reference to FIG. 1, where the same parts as those of the conventional one are denoted by the same reference numerals, and the explanation of the structure of the same parts will be omitted. In the figure, the side of the pedestal 5 is
A pedestal 5 is fixed to the base 1 by adhesively fixing it through a sealing glass 4 on a surface perpendicular to the surface of the pedestal 5. This is a measure based on experimental confirmation of the bonding force of the brazing filler metal 6 when increasing the pressure of the semiconductor pressure sensor and making it possible to apply pressure up to the withstand pressure limit of the gauge part 10. Furthermore, the pedestal 5 and the gauge part 10 are bonded together using a gold-silicon alloy material 8, and the lead pins 2 are plated with gold. Then, the cover 3 is welded and fixed to the base 1 in a vacuum to form a vacuum chamber 11. Therefore, the material of the adhesive part does not melt and flow out, and the vacuum chamber 11 can always maintain a constant reference pressure, and the adhesive force between the base 1 and the pedestal 5 is large, and it is possible to prevent an increase in size. The material of the base 1 and the cover 3 is not limited to metal, but the same effect can be obtained with an inorganic material such as ceramic, and the material of the pedestal 5 can also be made of an inorganic material other than metal such as silicon or glass. The effect of this can be obtained. Although the sealing glass 4 for fixing the pedestal 5 to the base 1 and the sealing glass for fixing the lead pins 2 are made of different materials, they can be made of one type by selecting the materials for the lead pins 2 and the base 1.

In this way, the semiconductor pressure sensor of this embodiment can maintain a good vacuum reference pressure because the pedestal is bonded to the base via the sealing glass on the side, and the gauge part and the pedestal are bonded via a gold-silicon alloy material. At the same time, it is possible to prevent the size from increasing.

FIG. 2 shows another embodiment. In the figure, a lead pin 2 is fixed to the flange portion 14 of the base 1 with a sealing glass 4 interposed therebetween, and a metal film 12 is formed on the side surface of the pedestal 5 by vapor deposition between the metal film 12 and the flange portion 14 of the base 1. are connected through soldering 13, and the metal film 12 is formed to improve solder joints. Therefore,
The bonding force of the solder joint 13 between the base 1 and the pedestal 5 becomes a shear force in the direction of pressure application, which is significantly stronger than before, allowing the sensor to be larger even when high pressure is applied without changing the area of the pedestal. can be prevented. Note that the metal film of the pedestal may be formed by plating or the like instead of vapor deposition.

〔Effect of the invention〕

As described above, the semiconductor pressure sensor of the present invention has the effect of being able to maintain the vacuum standard pressure within the vacuum chamber and preventing the sensor from becoming larger.

[Brief explanation of the drawing]

FIGS. 1 and 2 are sectional views of an embodiment of the semiconductor pressure sensor of the present invention, and FIG. 3 is a sectional view of a conventional semiconductor pressure sensor. DESCRIPTION OF SYMBOLS 1... Base, 2... Lead pin, 3... Cover, 4... Sealing glass, 5... Pedestal, 8... Gold silicon alloy material, 9... Gold thin wire, 1o.・・Gauge part,
11...Vacuum chamber. 1st mouth 2nd figure

Claims (1)

[Claims] 1. A gauge portion fixed to a pedestal so as to be able to sense pressure within the sensor; a base that seals and fixes the pedestal; and a gauge portion that is attached to the base in a sealed manner. has a lead pin whose end is connected via a thin gold wire, and a cover that is sealed and fixed to the base that covers the gauge part and the thin gold wire and forms a vacuum chamber, and the pressure in the vacuum chamber is set as a reference pressure. A semiconductor pressure sensor for detecting pressure, wherein the pedestal is sealed and fixed to the base by a surface perpendicular to the surface of the base. 2. The semiconductor according to claim 1, wherein the pedestal and the lead pin are sealed to the base via a sealing glass, and the pedestal and the gauge part are joined by an all-silicon alloy material. type pressure sensor. 3. The semiconductor pressure sensor according to claim 1, wherein a metal film is formed on the side surface of the pedestal, and the side surface and the base to which the lead pin is sealed in glass are joined by soldering.