JPS6154273B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor pressure transducer, and more particularly to an improvement in the structure of a semiconductor pressure transducer that utilizes the piezoresistance effect of a semiconductor such as silicon.

FIG. 1 is a cross-sectional structural diagram of an example of a conventional semiconductor pressure transducer. To explain the structure of a conventional semiconductor pressure transducer with reference to the drawings, a diaphragm 1 is made by processing a substrate made of a semiconductor single crystal into a diaphragm shape, and a gauge resistor 2 is attached to one surface (the upper surface in the figure) of the diaphragm 1. and metal electrode 3 is formed. A support base 4 having a concave cross-section is joined to the other surface (lower side in the drawing) of the diaphragm 1. This diaphragm 1 and support base 4
and constitute a semiconductor pressure transducer element. A semiconductor pressure transducer element in which the diaphragm 1 and the support base 4 are integrally joined is placed on the upper surface of the insulating package 5,
Fixed. External electrode leads 6 are fixed to both sides of the semiconductor pressure transducer on the upper surface of the insulating package 5, sandwiching the semiconductor pressure transducer. The external electrode lead 6 and the metal electrode 3 are electrically connected by a metal wire (lead wire) 7.

The conventional semiconductor pressure transducer configured in this manner has significant limitations in its intended use and location. This is because the gauge resistor 2, metal electrode 3, and metal wire 7 formed on the diaphragm 1 are each affected by the gas component to be measured, causing deterioration such as corrosion. In order to prevent this, the method shown in FIG. 2, which will be described later, has been proposed.

FIG. 2 is a cross-sectional structural diagram showing another example of a conventional semiconductor pressure transducer. The semiconductor pressure transducer shown in FIG. 2 is different from the semiconductor pressure transducer shown in FIG. An inner filling wall member 8' is provided on the diaphragm 1, and the portion surrounded by both wall members 8, 8' is filled with an inner filler 9 such as silicone rubber. In this way, the metal electrode 3 is
By covering parts that are easily corroded, such as the metal wires 7 and the external electrode leads 6, adverse effects such as corrosion caused by the gas components to be measured are prevented.

FIG. 3 is a cross-sectional structural diagram of still another example of a conventional semiconductor pressure transducer. The pressure transducer shown in FIG.
The filler material 9 is also placed on the upper surface of the diaphragm 1.
The passivation effect is further increased by filling the material with . This dramatically increases the passivation effect.

FIG. 4 is a cross-sectional structural diagram showing still another example of a conventional semiconductor pressure transducer. The semiconductor pressure transducer shown in FIG. 4 has side walls 8 formed on both outer sides of the external electrode lead 6 at the portions surrounding the semiconductor pressure transducer element, and a liquid 10 such as silicone oil placed in the portion surrounded by the side walls 8. By sealing the upper surface with the sealing plate 11, the semiconductor pressure transducer element is sealed with the liquid 1.
External pressure is transmitted through the liquid while the liquid is immersed in water. However, the structure shown in FIG. 4 has the disadvantage that the sealing plate 11 is required because it is necessary to contain the liquid, and that it is very difficult to manufacture.

Further, each of the conventional semiconductor pressure transducers shown in FIGS. 1 to 4 described above has various problems arising from their structure. In other words, the semiconductor pressure transducer element of the semiconductor pressure transducer needs to be fixed to the insulating package 5 in principle, but thermal strain stress generated due to the difference in thermal expansion coefficient between the semiconductor pressure transducer element and the insulating package causes the semiconductor pressure There was a problem in that the temperature characteristics were adversely affected by the accumulation in the conversion element.

As a solution to these problems, generally an object having the same thermal expansion coefficient as the semiconductor pressure transducer or a thermal expansion coefficient close to it is inserted between the insulating package 5 and the semiconductor pressure transducer, and the semiconductor pressure transducer is This is a method of fixing the conversion element. However, even in such a method, it cannot be denied that the fixed state changes in various ways and the temperature characteristics vary widely.

Therefore, this invention was made in order to solve the various problems of the conventional ones as described above, and it is a semiconductor pressure converter that can efficiently transmit external pressure without being adversely affected by temperature changes. The purpose is to provide equipment.

The gist of this invention was made in view of the fact that the cause of adverse effects due to temperature changes is caused by the difference in coefficient of thermal expansion between different metals when a semiconductor pressure transducer element is fixed to an insulating package. , a semiconductor pressure transducer element is embedded in a material that can absorb changes due to thermal expansion.

FIG. 5 is a cross-sectional structural diagram of a semiconductor pressure transducer according to an embodiment of the present invention. The specific structure of the semiconductor pressure transducer of this embodiment will be explained with reference to FIG. 5. The diaphragm 1 is made by processing a single crystal semiconductor substrate into a diaphragm shape, ) is fixed to a support base 4.
A cavity is formed at the joint between the diaphragm 1 and the support base 4. As a method of forming this cavity, the center of the other side of the diaphragm 1 is formed into a hollow shape as shown in the figure, and the support base 4 is formed into a flat shape and the two are joined together, or the method shown in FIGS. As shown in FIG. 4, the other surface of the diaphragm 1 may be made the same plane, and the upper surface side of the support base 4 may be formed in a concave shape. This diaphragm 1 and support base 4 are combined to constitute a semiconductor pressure transducer. On the other hand, the insulating package 5 has an external electrode 6 fixed to the outside of the arrangement position of the semiconductor pressure transducer element and a filling wall member 8 fixed to the upper surface of the external electrode 6, or the insulating package 5 and the filling wall are fixed to the outside thereof. The member 8 is integrally molded. Then, the portion surrounded by the filling wall member 8 is filled with a filling material 9. At this time, filling of the filler 9 is carried out by forming a cavity in the center thereof into which a semiconductor pressure transducer can be enclosed, and filling the cavity with the semiconductor pressure transducer and a liquid 10 such as silicone oil. . In this way, a structure is obtained in which the entire semiconductor pressure transducer element is immersed in a liquid such as silicone oil and sealed with the filler material 9.

If configured as in the embodiment shown in FIG. 5, the insulating package 5 and the semiconductor pressure transducing element (supporting base) do not come into contact with each other in any way, but through the filler or liquid, so even if there is a temperature change, heat will not be generated. This has the advantage of preventing adverse effects due to differences in expansion rates. Furthermore, since the semiconductor pressure transducer element is floating in the liquid and the liquid is sealed with an internal filling material, even if vibrations are applied from the outside, the filling material 9 surrounding the liquid will absorb these vibrations. It has the advantage of absorbing and not being adversely affected by vibrations. In addition, in terms of temperature characteristics, since the semiconductor pressure transducer is floating in the liquid 10, parts with different coefficients of thermal expansion do not come into contact with each other, and the semiconductor pressure transducer is in a completely free state, resulting in a good condition. It has the advantage of providing good temperature characteristics.

FIG. 6 is a cross-sectional structural diagram of a semiconductor pressure transducer according to another embodiment of the present invention. This embodiment differs from FIG. 5 in that a part of the semiconductor pressure transducer element (the diaphragm 1 in the figure) is immersed in the liquid 10, and the other part (the support base 4) is filled with a filler. It is fixed in a state. In the structure shown in FIG. 6, for example, the semiconductor pressure transducer element is suspended from the surface of the insulating package 5 and filled with a filler 9, and a liquid 10 is poured onto the diaphragm 1 midway.
By further filling the periphery with a filler material, the diaphragm 1 is made to be sealed in contact with the liquid. Note that the same parts as in FIG. 5 are indicated by the same reference numerals, and the explanation thereof will be omitted.

If the structure is as shown in the embodiment shown in FIG. 6, the semiconductor pressure transducer element is supported by the gel-like filler material, so there is an advantage that the vibration resistance can be further increased.

FIG. 7 is a sectional view of a semiconductor pressure transducer according to still another embodiment of the present invention. In this example,
The semiconductor pressure transducer element is held floating above the surface of the insulating package 5 and filled with a filler 9 up to a slightly upper surface of the diaphragm 1, and further filled with a filler so as to seal the liquid 10 only on the upper surface of the diaphragm 1. It's a thing. Note that the same parts as in FIG. 5 are indicated by the same reference numerals.

If configured as in the embodiment shown in FIG. 7, the external pressure can be efficiently transferred to the diaphragm 1 of the semiconductor pressure converting element.
There are advantages that can be conveyed to

As described above, according to the present invention, it is possible to realize a semiconductor pressure transducer device that has excellent temperature characteristics and can efficiently transmit external pressure to a semiconductor pressure transducer element.

[Brief explanation of the drawing]

1, 2, 3, and 4 are cross-sectional structural views of conventional semiconductor pressure transducers. FIG. 5 is a cross-sectional structural diagram of a semiconductor pressure transducer according to an embodiment of the present invention. 6 and 7 are cross-sectional structural views of a semiconductor pressure transducer according to another embodiment of the present invention. In the figure, 1 is a diaphragm, 2 is a gauge resistor, 3 is a metal electrode, 4 is a support base, 5 is a support package, 6 is an external electrode lead, 7 is a metal wire, 8 is a filling wall member, 9 is a filling material, 10 indicates liquid.

Claims (1)

[Scope of Claims] 1. A diaphragm formed by processing a substrate made of a semiconductor crystal device into a diaphragm shape and forming a diffusion gauge layer on the upper surface of one side of the diaphragm, and a diaphragm bonded to the other side of the diaphragm. a support for forming a cavity between the semiconductor pressure transducer and the other surface of the semiconductor pressure transducer, a metal wire having one end electrically connected to the semiconductor pressure transducer, and the other end of the metal wire. an external electrode lead that is electrically connected to an end side; a wall member is formed in a portion that electrically insulates and supports the external electrode lead and surrounds a periphery of the semiconductor pressure transducing element outside the external electrode lead; an insulating package consisting of the semiconductor pressure transducing element, and integrally sealing the semiconductor pressure transducing element and the liquid so that at least one side of the semiconductor pressure transducing element is immersed in the liquid when the semiconductor pressure transducing element is placed in the insulating package. Semiconductor pressure transducer with filler. 2. The semiconductor pressure transducer device according to claim 1, wherein the filler seals the semiconductor pressure transducer between the liquid and the semiconductor pressure transducer so that the entire semiconductor pressure transducer is immersed in the liquid. 3. The semiconductor pressure transducer according to claim 1 or 2, wherein the filler is an atmosphere-resistant material. 4. The semiconductor pressure transducer device according to claim 1 or 2, wherein the filler is an electrically insulating material. 5. The semiconductor pressure transducer according to claim 1 or 2, wherein the filler is a flexible material. 6 A diaphragm formed by processing a substrate made of a semiconductor crystal device into a diaphragm shape and forming a diffusion gauge layer on the upper surface of one side of the diaphragm, and a diaphragm that is bonded to the other side of the diaphragm and formed on the other side of the diaphragm. a support base for forming a cavity therebetween; a metal electric wire having one end electrically connected to the semiconductor pressure conversion element; and an electric wire connected to the other end of the metal electric wire. an external electrode lead to be connected; an insulating package that electrically insulates and supports the external electrode lead and includes a wall member formed in a portion surrounding the arrangement of the semiconductor pressure transducing element outside the external electrode lead; Filled around the semiconductor pressure transducer while the semiconductor pressure transducer is placed in the insulating package, and facing the upper surface of one side of the semiconductor pressure transducer so as not to be in contact with the semiconductor pressure transducer. A semiconductor pressure transducer equipped with a liquid-sealed filling material.