JPH0241903B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil-sealed, pressure-equalized semiconductor device, and particularly to an oil-sealed, pressure-equalized semiconductor device having a structure suitable for use under conditions of high external atmospheric pressure. Submersibles, unmanned aerial vehicles, etc. used in deep seas of 3,000 to 10,000 m class require power control devices such as inverters, converters, and choppers in order to efficiently control their power supplies. In order to use these devices in such deep seas, they must be housed in pressure-resistant containers. Pressure-resistant containers that can withstand water pressure at great depths are heavy, making submersibles, unmanned aerial vehicles, etc. heavier. For this reason, if an attempt is made to increase the buoyancy, the pressure vessel itself will become larger, making it impossible to assemble a submersible or the like of a predetermined size. Therefore, semiconductor devices used under such conditions are strongly required to withstand large pressures and at the same time to be small and lightweight. In semiconductor devices that are conventionally manufactured,
There was nothing that could withstand use under an external pressure of about 300 Kgf/cm ² to 1000 Kgf/cm ² . FIG. 1 is a cross-sectional structural diagram of a conventional flat semiconductor device, and numeral 1 in the figure is an insulator tube made of ceramic or the like. A predetermined semiconductor element 2 is placed inside the insulator cylinder 1.
is accommodated. The semiconductor element 2 is fixed between its circumferential surface and the inner wall surface of the insulator cylinder 1 via a positioning ring 3. External electrodes 4, 4 are pressed into contact with both the upper and lower principal surfaces of the semiconductor element 2. An upper flange 5a is provided between the external electrodes 4, 4 and the insulator cylinder 1.
and the lower flange 5b are brazed to each other to form a storage container 6 for the semiconductor element 2. A storage container 6 in which semiconductor elements are stored in an airtight state in this way
Inert gas 7 is sealed inside. When high external pressure is applied to such semiconductor devices,
Since the material forming the exterior of the device has low steel properties, it cannot withstand external pressure, and, for example, the flange portion deforms and breaks, impairing the airtightness of the device and deteriorating its initial electrical characteristics. That is, such a semiconductor device cannot be used under high external atmospheric pressure. FIG. 2 shows an improved semiconductor device in which electrical insulating oil is sealed inside the conventional semiconductor device. 8 in the figure is electrical insulating oil. Also, the same numbers as in FIG. 1 indicate equivalent components. In such a semiconductor device, the pressure of the internal electrical insulating oil also increases as the external pressure increases, so it is possible to obtain a pressure-equalizing package in which deformation of the exterior is alleviated. However, even insulating oil causes volume changes due to pressure and temperature, so a structure simply filled with oil will not be able to withstand sudden changes in pressure under external pressure above a certain level. I understood. That is, under high external atmospheric pressure, mechanically weak parts such as the flanges 5a and 5b and the brazed parts are deformed as shown by the two-dot chain line 11 in FIG. 3, and the storage container 6 is damaged. As a result, there was a problem that the electrical characteristics of the semiconductor element 2 were impaired. Attempts to absorb changes in the volume of insulating oil due to changes in pressure by adding a bellows to the outside of the device have been put to practical use, for example, in oil-sealed pressure equalizing motors as shown in FIG. 21 in the figure is a rotor,
The rotating shaft 22 is connected to the frame 2 through a bearing 23.
4 to the outside. A stator 25 is attached to the inner peripheral surface of the frame 24 so as to face the rotor 21 . The end of the rotating shaft 22 at the rear end of the frame 24 is surrounded by a pressure equalizing bellows 26 . Equalizing pressure bellows 26 and frame 24
Pressure-equalizing oil 27 is sealed in the inside surrounded by. In the oil-sealed pressure equalizing motor mentioned above, it is possible to install a bellows made of a soft material such as rubber, but in the case of a semiconductor device, the semiconductor element housed in the container has a very sensitive structure. Due to its high temperature, an extremely high degree of sealing and an inert internal atmosphere are required. Therefore, hermetically sealed metal and ceramic walls are generally used. Furthermore, in consideration of corrosion resistance, it is difficult to use a metal wall that is too thin. Therefore, if an attempt is made to add a bellows externally as shown in Fig. 5, the internal volume of the device will become too large, and the amount of sealed oil will have to be increased, which will increase the amount of volume change. Requires large bellows. Such a structure is difficult to implement due to the above-mentioned problem in handling the size restriction of the entire system and also from the viewpoint of manufacturing cost. The present invention has been made in view of this point, and improves the excellent characteristics of semiconductor devices by absorbing changes in the volume of electrical insulating oil through elastic deformation of a pair of flanges having U-shaped grooves. The object of the present invention is to provide an oil-sealed pressure-equalizing semiconductor device which has a simple structure and high breakdown voltage. That is, the present invention provides a semiconductor element having at least two main surfaces, an insulator tube housing the semiconductor element while supporting the semiconductor element at its end surfaces, and two external electrodes provided in contact with each of the main surfaces. and is attached between the two external electrodes and the insulating cylinder so as to isolate and seal the semiconductor element from outside air, and is elastically deformed in accordance with pressure changes in the external atmosphere, and surrounds the semiconductor element. two flange portions having substantially the same shape as each other and having a hollow portion communicating with the region and a substantially U-shaped groove in cross section formed on the surface side of the root portion of the external electrode; the two flange portions; the two external electrodes; and an oil-sealed, pressure-equalized semiconductor device, comprising: an electrically insulating oil bath sealed in an interior surrounded by the insulating cylinder so as to seal the semiconductor element. Embodiments of the present invention will be described below with reference to the drawings. FIG. 6 is a cross-sectional view of one embodiment of the present invention.
30 in the figure is a semiconductor element. semiconductor element 30
is housed in an insulator cylinder 31 made of ceramic or the like. The semiconductor element 30 is fixed by a positioning ring 32 interposed between its side end surface and the inner wall surface of the insulator cylinder 31. External electrodes 33a and 33b are attached to both the front and back principal surfaces of the semiconductor element 30. A lower flange 34b is attached between the lower end of the insulator cylinder 31 and the external electrode 33b on the back side. An upper flange 34a is attached between the upper end of the insulator tube 31 and the outer electrode 33a on the front surface side. The upper flange 34a and the lower flange 34b are bent between the external electrodes 33a, 33b and the insulator tube 31, and the bent portion forms a hollow portion 33c that communicates with a region surrounding the semiconductor element 30. . Furthermore, a groove 34c having a substantially U-shaped cross section is formed at the base of the external electrodes 33a, 33b of the upper flange 34a and lower flange 34b so as to surround the external electrodes 33a, 33b. Upper flange 34a and lower flange 34b (hereinafter referred to as
It will simply be referred to as a flange portion 34. ) is designed to elastically deform when subjected to external force due to the U-shaped groove 34c and the hollow portion 33c. External electrode 3
3a, 33b, insulator cylinder 31 and flange part 34
The storage container 35 is constructed by the following. Electrical insulating oil 36 is sealed in the storage container 35 so as to hermetically seal the semiconductor element 30 . For example, silicone oil is used as the electrical insulating oil. Electrical insulating oil 3 is placed on the side of the insulator cylinder 31.
No. 6 enclosure tubes 37 are led out, and their tips are sealed. Oil-sealed pressure-equalizing semiconductor device 4 configured as described above
According to No. 0, a U-shaped groove 34c is formed in the flange portion 34, and a hollow portion 33c is formed by the flange portion 34, so as shown in FIG.
As shown by a dashed line 41, the flange portion 34 is elastically deformed to absorb the pressure. Furthermore, since the flange portions 34 are provided in pairs at the upper and lower portions on both main surfaces of the semiconductor element 30, the pressure absorption effect can be increased. Similarly, even if the volume of the electrical insulating oil 36 changes due to temperature or pressure changes,
It is easily absorbed by the flange portion 34. the result,
It is possible to prevent uneven pressure from being applied to the semiconductor element 30 and to exhibit excellent element characteristics. Moreover, since the storage container 35 is in a state in which the electrical insulating oil 36 is sealed inside, it is possible to improve the withstand voltage. In addition, when assembling a power control device with a stack structure, as shown in FIG.
2 can be easily constructed by pressing them together at several hundred to several thousand kgf. As explained above, according to the oil-sealed pressure-equalized semiconductor device according to the present invention, the change in the volume of electrical insulating oil can be
This is absorbed by the elastic deformation of a pair of flange portions having a shape groove, thereby exhibiting the excellent characteristics of the semiconductor element, and having a simple structure and high withstand voltage.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of conventional pressure-equalizing semiconductor devices, respectively, and FIG. 3 is an illustration showing a state in which the flange portion of the semiconductor device shown in FIG. 2 is deformed by external pressure. 5 is a cross-sectional view of a conventional oil-sealed pressure-equalizing semiconductor device, FIG. 4 is a cross-sectional view of an oil-sealed pressure-equalizing motor, and FIG. 6 is a cross-sectional view of an embodiment of the present invention. FIG. 7 is an explanatory diagram showing the deformed state of the flange portion of the oil-sealed pressure-equalizing semiconductor device of the same embodiment, and FIG. 8 shows a stacked structure incorporating the oil-sealed pressure-equalizing semiconductor device of the same embodiment. It is an explanatory diagram. 30... Semiconductor element, 31... Insulator cylinder, 32
... Positioning ring, 33a, 33b ... External electrode, 33c ... Hollow part, 34a ... Upper flange, 34b ... Lower flange, 34c ... U-shaped groove, 35 ... Storage container, 36 ... Electrical insulating oil ,3
7...Enclosed tube, 40 ...Oil sealed pressure equalized semiconductor device,
42...Stack board.

Claims (1)

[Claims] 1. A semiconductor element having at least two main surfaces, an insulating cylinder supporting and accommodating the semiconductor element on its side end surfaces, and 2.
one external electrode, which is attached between the two external electrodes and the insulating cylinder so as to isolate and seal the semiconductor element from the outside air, and which elastically deforms in accordance with pressure changes in the external atmosphere; two flange portions having substantially the same shape as each other, each having a hollow portion communicating with a region surrounding the element and a substantially U-shaped groove in cross section formed on the surface side of the root portion of the external electrode; 1. An oil-sealed pressure-equalizing semiconductor device, comprising: two external electrodes; and electrical insulating oil sealed in an interior surrounded by the insulating cylinder so as to seal the semiconductor element.