JPH0329829A - semiconductor pressure transducer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pressure transducer used for detecting or measuring pressure in a wide range of industrial fields including automobiles, and in particular, to a pressure transducer in which a silicon pressure-sensitive diaphragm chip is sealed in a metal container. The present invention relates to a material structure of a pedestal for a silicon pressure-sensitive diaphragm of a semiconductor pressure transducer.

[Conventional technology]

The general basic structure of a semiconductor pressure transducer is a silicon pressure-sensitive diaphragm chip with an equal coefficient of thermal expansion.
For example, a method of bonding to a container via a pedestal made of silicon has been used. This is to prevent stress due to the difference in thermal expansion coefficient between the chip and the pedestal that supports the chip (hereinafter referred to as thermal stress) from deforming the diaphragm, resulting in the same result as deforming the diaphragm due to measurement pressure. It is. Figure 3 shows an example of the structure of a conventional semiconductor pressure transducer using a pedestal made of silicon and silicon, which have the same coefficient of thermal expansion.
is joined by solder 4 to the upper part of a pedestal 8 made of silicon and having a pressure to be measured introduction hole 8a. This pedestal 8 is similarly joined with solder 4 to the upper part of the pressure guiding pipe 3 through which the pressure to be measured is introduced. For the reasons mentioned above, it is desirable that the material of the pressure guiding pipe 3 has a coefficient of thermal expansion close to that of the pedestal, for example,
A re-Ni alloy or the like is used. The silicon pressure-sensitive diaphragm chip 1 is protected from the outside by joining a container lid 5 to a container bottom 6 by welding or the like.

The space 7 formed by the container lid 5 and the container bottom 6 can be either closed or open depending on the purpose of pressure measurement or detection, ie whether absolute pressure measurement or relative pressure measurement. For absolute pressure measurement, the space 7 is used as a reference pressure chamber, which is maintained at a vacuum or a predetermined pressure by means not shown and hermetically sealed. To measure the relative pressure, for example, a hole is made in the container lid 5 and the space 7 is opened to the atmosphere. The output signal of the silicon pressure sensitive diaphragm 1 is taken out to the outside of the container through an airtight through terminal (not shown).

[Problem to be solved by the invention]

In the aforementioned semiconductor pressure transducer, in order to alleviate thermal stress, a pedestal made of silicon, which is the same material as the silicon pressure-sensitive diaphragm, is used. I'm trying to connect it. However, as mentioned above, the thermal stress between the pedestal made of silicon and the pressure vibrator is caused by the thermal expansion coefficient of the metal and the silicon It is difficult to completely match that of the temperature and heat stress occurs. Due to this thermal stress, there is a problem in that the pedestal breaks due to the relatively low external stress that normally occurs.

An object of the present invention is to provide a pedestal made of high-strength silicon that will not break under the relatively low external stress that normally occurs even if the thermal stress described above occurs.

[Means to solve the problem]

In order to solve the above-mentioned problems, the bottom of the container through which the pressure vibrator for supplying the pressure to be measured is attached to the silicon pressure-sensitive diaphragm of the present invention is attached, and the lid of the container are hermetically connected. In a semiconductor pressure transducer, a silicon pressure-sensitive diaphragm tysop is enclosed in a metal container which is connected to the pressure guiding pipe through a pedestal having a pressure introduction hole, and the pedestal has a joint surface of the pedestal. The direction is (10
0) single crystal silicon.

[Effect]

In the semiconductor pressure transducer of the present invention, single-crystal silicon is used for the pedestal, and the plane orientation of the joint surface between the pedestal and the pressure-conducting pipe is ga (100), so its breaking strength is shown in Figure 2. Other plane orientations, such as (111), as shown in
(110), increases by 12% and 34%, respectively.

As a result, a pedestal made of silicon with high strength against external stress can be obtained.

〔Example〕

FIG. 1 is a cross-sectional view of one embodiment of the semiconductor pressure transducer of the present invention, in which a silicon pressure-sensitive diaphragm tip 1 has a pedestal 2 made of single-crystal silicon having a measurement target pressure introduction hole 2a.
It is joined to the upper part of the board with solder 4. This pedestal 2 is similarly joined with solder 4 to the upper part of a pressure guiding pipe 3 through which the pressure to be measured is introduced.

For the reasons mentioned above, it is desirable that the material of the pressure guiding pipe 3 has a coefficient of thermal expansion close to that of the pedestal, and for example, a Fe--Nl alloy or the like is used. Here, in the pedestal 2 made of single crystal silicon, the plane orientation of the joint surface between the pedestal and the pressure guiding pipe 3 is (100).

Figure 2 shows the breaking strength of single-crystal silicon in a push-down test for each plane orientation, with the (100) plane increasing by 12% compared to the (111) plane, and 34% higher than the (110) plane. It is shown that. Therefore, the semiconductor pressure transducer of the present invention, which includes a pedestal made of single-crystal silicon with the bonding surface oriented (100), can withstand external stress in proportion to this breaking strength.

The structure and function of the container lid 5, container bottom 6, and space 7 are similar to those of the semiconductor pressure transducer shown in FIG.

〔Effect of the invention〕

In the semiconductor pressure transducer of the present invention, since the pedestal is made of single-crystal silicon with the plane orientation of the adhesive surface (100), the single-crystal silicon According to the fracture strength of 12% for those using plane orientation (111), and 34% for those using plane orientation (110), high strength against external stress is obtained, which usually occurs. The pedestal no longer breaks or shifts under relatively low external stress.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the semiconductor pressure transducer of the present invention, FIG.
Figure 2 is a cross-sectional view of an example of a conventional semiconductor pressure transducer. 1: Silicon pressure sensitive diaphragm chimp 2: Pedestal [made of single crystal silicon with plane orientation (100)] 2a: Pressure introduction hole 3: S pressure pipe 5: Container lid part -7- Atsushi V\Anchor

Claims (1)

[Scope of Claims] 1) In a metal container configured by airtightly joining a container bottom and a container lid, through which a pressure guiding pipe for supplying measured pressure to a silicon pressure-sensitive diaphragm chip is attached. , a semiconductor pressure transducer including a silicon pressure-sensitive diaphragm chip bonded to the pressure guiding pipe via a pedestal having a pressure introduction hole, wherein the pedestal is a single crystal whose bonding surface has a plane orientation of (100). A semiconductor pressure transducer characterized by being made of silicon.