JP2003309133A - High thermostability semiconductor element and power converter using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor element wherein a plurality of SiC semiconductor chips are incorporated in a flat package, for attaining high reliability in higher temperature use and also durability in higher temperature use without causing oxidation deterioration, and provide a power converter that exerts higher performance comparing with a conventional power converter using an Si semiconductor element. <P>SOLUTION: The semiconductor element of high thermostability has such an arrangement that; a plurality of semiconductor chips are incorporated, being juxtaposed, in the flat package whose interior is airtightly sealed by a pair of common electrode plates and an insulating outer cylinder made of ceramics; and a Pt layer is formed at least on the externally exposed surface of each of the common electrode plates. Such an element is used for a power converter for exerting high performance. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel high heat resistant semiconductor element in which a plurality of semiconductor chips are connected in parallel and incorporated in one package, and a power converter using the same.

[0002]

2. Description of the Related Art The technology of power electronics, which controls the main circuit current by making full use of the technology of Si semiconductor electronics, has been applied in a wide range of fields as its performance has been improved, and its application is being expanded. In addition to diodes and thyristors, MOS type field effect transistors (hereinafter abbreviated as MOSFET), which are MOS control devices for controlling the main current by the input signal to the MOS structure gate, and insulated gate bipolar transistors (hereinafter abbreviated as IGBT). And so on,
It is widely used as a power switching device for applications such as motor PWM control inverters.

However, in recent years, high-performance devices that have reached the limit of Si devices have been developed,
Aiming to further improve the performance of power devices, studies on power devices using new semiconductor materials such as SiC, GaN, and diamond, which replace Si, have begun.
Among them, SiC attracts attention as the most promising device,
Research and development is in progress. Since SiC has a larger dielectric breakdown electric field and a wider band gap than Si, it has the characteristics that it can operate semiconductors at high temperatures.
Especially, high withstand voltage suitable for high power control, use at high temperature,
That is, it is expected to realize a system in which the cooling system is simplified.

In the conventional Si semiconductor power device mounting mode, a discrete element in which one chip for low power capacity is mounted on a heat dissipation plate and then the whole is resin-molded, an IGBT called a module structure for larger capacity, etc. The package form of is becoming mainstream.

In the above-mentioned module structure, the main electrode on the second main surface of the semiconductor chip is generally soldered on a metal base which also serves as a heat radiator via an insulating plate, and the main electrode (emitter electrode) on the first main surface is The control electrode (gate electrode) is wire-bonded with a conductor such as aluminum between the emitter provided in the resin case and the external lead-out terminal for the gate, and is led out to the outside of the package. The package is filled with silicone gel to ensure the reliability of the chip.

On the other hand, as another mounting form of a power device, an element in which external electrodes are formed on both sides of a flat element has been developed, and a diode, a thyristor, a GTO (gate turn-).
offthyristor), IGBT (insulated gate bipolar trans)
istor) has been applied. Especially in the flat element of the IGBT, a plurality of Si chips are installed in parallel in a package,
A package with a pressure contact structure has been proposed in which the emitter electrode and the collector electrode formed on the main surface of the package are connected to the upper and lower electrode plates provided on the package side by external pressure to be surface-connected and pulled out. In particular, it is a mounting form suitable for a large capacity device.

For example, in Japanese Patent Laid-Open No. 08-088240, 21 Si semiconductor chips (9 IGBT and 1
A flat IGBT package having two diodes) is disclosed.

An example of this package structure is shown in FIG. The second main surface (collector side) of the semiconductor chip 25 is mounted on one large electrode substrate (Mo) 24 provided on the common electrode (Cu) 22 of the package, and the first main surface (emitter side). ) Is a common electrode (Cu) 21 of the package via a separate small pressure contact plate (Mo) 23 separated for each chip 25.
It has a structure to connect to. Furthermore, the semiconductor chip 2
5 is positioned in the package by each semiconductor chip 25.
The chip chip 27 made of resin and the external frame 26 integrated with the resin chip frame 27 installed on the outer periphery of the chip are collectively processed.

[0009] WO98 / 43301 discloses a semiconductor device having an IGBT chip between intermediate electrodes provided between common electrodes, and a flange between the common electrodes covered with an insulating outer cylinder. There is.

[0010]

[Problems to be Solved by the Invention] In order to maximize the performance of high heat-resistant semiconductors such as SiC, GaN, diamond, etc., it is much higher than that of Si (operating temperature of 150 ° C or less). It is necessary to operate at a high temperature of 300 ° C or higher.

However, in the mounting form used in the conventional Si semiconductor as seen in the above-mentioned known example, resin components are frequently used as built-in mounting parts, and the heat resistance of the original material itself is There is a problem in terms. Furthermore, in the mounting of the flat IGBT package described above, oxygen-free copper is used as the material of the common electrode substrate, and when used at a high temperature of 300 ° C. or higher, deformation due to pressure is a serious problem. In addition, the common electrode exposed to the outside of the package and the metal parts such as the flange parts for hermetic sealing are oxidized to increase the electric resistance, or are deteriorated due to peeling of the oxide film. I have a problem. Although there is an example of applying a Ni plating film to an oxygen-free copper electrode, Ni cannot prevent oxidation at a high temperature of 300 ° C or higher.

An object of the present invention is to provide a semiconductor device in which a plurality of SiC semiconductor chips are incorporated in one flat package, which is highly reliable for use at a higher temperature and is free from oxidative deterioration. An object is to provide a semiconductor device that can be used at high temperatures.

Another object of the present invention is to provide a power converter with higher performance than the conventional power converter using a Si semiconductor element.

[0014]

The present invention is directed to a pair of common electrode plates and a semiconductor chip having a higher heat resistance than a plurality of silicons provided side by side with the intermediate electrodes between the common electrode plates. An insulating ceramic outer cylinder joined to the outer periphery between the common electrode plates, and an insulating ceramic inner cylinder accommodating each of the semiconductor chips and the intermediate electrodes, the insulating ceramic outer cylinder A high heat-resistant semiconductor element having a non-oxidizing gas filled therein.

Further, according to the present invention, a pair of copper alloy common electrode plates, a plurality of semiconductor chips provided in parallel between the common electrode plates via an intermediate electrode, and an outer periphery between the common electrode plates. A high heat-resistant semiconductor element, comprising: an insulating ceramic outer cylinder joined to each other; and an insulating ceramic inner cylinder accommodating each of the semiconductor chips and the intermediate electrodes.

The insulating ceramic outer cylinder is integrally provided with fins for enhancing electric insulation on the outer circumference thereof, and each of the semiconductor chips is provided in the insulating ceramic inner cylinder. That the insulating ceramic outer cylinder is brazed to the common electrode plate via a metal flange or directly brazed to the common electrode plate, at least one of the metal flanges is in a radial direction. Having an expandable structure, providing a supply port for supplying a non-oxidizing gas to the insulating ceramic outer cylinder, and preventing at least the surface of the common electrode plate exposed to the outside air from being oxidized by the outside air. It is preferable that a film is provided.

Further, according to the present invention, a plurality of semiconductor chips are arranged side by side between the common electrode plates in a flat package whose inside is hermetically sealed by a pair of common electrode plates and an insulating ceramic outer cylinder. The Pt layer is formed on at least the surface of the common electrode plate exposed to the outside, which is a high heat resistant semiconductor element. It is preferable that the Pt coating has a Ni layer on its base.

The pair of common electrode plates are made of a precipitation hardening type copper alloy, and the pair of common electrode plates contain Cu as a main component and at least one selected from Zr, Fe, Cr, Ti, Ag and Sn. It is made of an alloy containing 0.1 to 5% by weight, preferably 0.3 to 1.5% by weight, and the common electrode plate and the outer cylinder of the insulating ceramics are joined by a brazing material containing Ag as a main component, The common electrode plate and the insulating ceramic outer cylinder have an iron-nickel alloy having a coefficient of thermal expansion of 2 to 5 × 10 ⁻⁶ / ° C., Fe-32 to 42 wt% Ni alloy, and Fe-30 to 40 wt% Ni. −5 to 2
It is bonded by a brazing material containing Ag as a main component through a 0 wt% Co alloy flange member, and at least one of the semiconductor chips has a main current control function of controlling a main current by an external control signal. It is preferable that the semiconductor chip is SiC.

The high heat-resistant semiconductor element of the present invention comprises a flat package whose inside is hermetically sealed by a pair of common electrode plates and an outer cylinder of insulating ceramics, and at least the first main electrode on the first main surface. A semiconductor element in which a plurality of semiconductor chips having at least a second main electrode are juxtaposed on a second main surface, and the metal is exposed on at least the surface of the pair of common electrode plates exposed to the outside of the package. On the surface of the part
It is characterized by having a Pt layer.

The power converter of the present invention is characterized by using the above-mentioned high heat-resistant semiconductor element as a main conversion element.

The material for the common electrode is preferably a metal having a high resistance to pressure deformation at high temperature and a low electric resistance. From the above viewpoints, as a result of various tests and studies, it was found that the precipitation hardening type copper alloy is particularly preferable among the copper alloys. Among them, the main component is Cu, Zr, Fe, Cr,
0.1 or more of at least one element selected from Ti, Ag, and Sn
Alloys containing ˜5.0 wt% are preferable, and copper-based alloys containing Zr, Fe, and Cr are particularly preferable because they have large pressure deformation resistance.

Beryllium copper is generally used as a heat-resistant copper alloy, but it has poor wettability with a silver brazing material and is not suitable for manufacturing a hermetically sealed and reliable structure with a flange material or a ceramic material. I found out. Compared to this,
It has been confirmed that the above-described copper alloy can produce a highly heat-resistant semiconductor element having excellent reliability without causing such a problem.

As a result of examining various material constitutions for the surface oxidation protection film, it was found that Pt has the best heat resistance, oxidation resistance and electric conductivity even for long-term operation at high temperature.

In the case of a complex structure such as the present invention,
Various materials are mixed as the metal material exposed to the outside. Therefore, in order to form a Pt protective film with sufficient adhesion to various materials, Ni is required.
It is also effective to further provide the film as a base film of the Pt film. It has been found that Ni secures the adhesion to the Pt film and can well suppress the diffusion reaction with the copper alloy at high temperature, so that the long-term reliability at high temperature can be further improved. Further, since Ni has a coefficient of thermal expansion intermediate between that of the copper alloy and Pt, the thermal stress can be relaxed, and therefore the reliability of the protective film can be further improved. When it is expected to be used under more severe conditions such as heat cycle, it is also effective to apply thin Au strike plating between the Ni film and the Pt film to improve the adhesion.

The method of forming the film may be plating, sputtering, vapor deposition, or the like. However, in order to form a protective film on the entire metal surface having a complicated shape as in this embodiment, The plating method is most preferable. The optimum film thickness is selected depending on the temperature conditions used and the time conditions to be compensated.

The non-oxidizing gas filled in the insulating ceramic outer cylinder is preferably nitrogen gas, SF ₆ gas, or a mixed gas thereof.

As the high heat resistant semiconductor, a SiC semiconductor is preferable, but a high heat resistant semiconductor that can operate at a temperature higher than that of Si such as GaN and diamond other than SiC can be similarly implemented.

The present invention is intended for general high heat-resistant semiconductor devices having a first main electrode on the first main surface and a second main electrode on the second main surface, and includes a PN diode, a Schottky diode,
In addition to various diodes such as SID, insulated gate transistor (MOS transistor), insulated gate thyristor (MOS
A semiconductor element with a control electrode such as a control thyristor, that is, a first main electrode and a control electrode on the first main surface and a second main electrode on the second main surface, and a main current control function by a control signal from the outside. The same can be applied to the case of having.

Further, according to the present invention, a device in which a large number of diode chips alone are positioned and mounted in a flat package, MO
Semiconductor element consisting only of switching semiconductors such as SFET,
Also, it can be applied to various elements such as a semiconductor element in which a plurality of diode chips and switching semiconductor chips are arranged in antiparallel.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIG. 1 is a vertical sectional view of a central portion of a flat semiconductor device of the present invention. In this embodiment,
This is an example of incorporating a plurality of SiC chips. SiC chip 3
The main electrodes are formed on both main surfaces (upper side surface and lower side surface in the figure) of each. On the SiC chip 3, an intermediate electrode 4 that also serves as heat dissipation and electrical connection is arranged above and below in contact with each main electrode of the chip 3, and this is the first common electrode that serves as an external electrode of the flat semiconductor device. It is sandwiched between 1 and the second common electrode 1. The top of the drawing is the positive pole and the bottom is the negative pole. The pair of common electrodes 1 are externally insulated by a cylindrical insulating ceramics outer cylinder 2, and the common electrode 1 and the insulating ceramics outer cylinder 2 have a low thermal expansion property of Fe-36wt%. It has a hermetic structure in which the inside of the package is sealed and sealed by the Ni alloy flange member 6. The upper flange member 6 has a bellows shape capable of expanding and contracting in the radial direction, and the common electrode 1 and the insulating ceramic outer cylinder 2 are airtightly joined with a silver (Ag) brazing material. A chromium copper alloy containing 0.4 to 1.2 wt% of Cr was used as the material of the common electrode. Similarly, it is preferable that the lower flange member 6 also has a bellows shape so that it can be expanded and contracted in the radial direction, and the stress in the radial direction is relaxed.

These metal flange members 6 are brazed to the recesses provided in the upper part of the upper common electrode and the recesses provided in the lower part of the lower common electrode, respectively. Are welded to each other by metal flanges 6 separately provided by brazing corresponding to the upper common electrode 6, and the lower flange member 6 is brazed to the lower common electrode 1. Since the welded joints of the upper metal flanges 6 have desired lengths, the upper common electrode 1 is extended even when it is thermally expanded upward.

Each of the SiC chips 3 is housed in a quadrangular ceramic insulating support 5 having an inner peripheral surface side corresponding to the size and shape of each intermediate electrode 4, and has a height that does not contact the common electrode. It is The contact area with the SiC chip 3 is formed such that the upper part of the intermediate electrode 4 is smaller and the lower part is larger than the upper part. This contact structure is set in terms of the breakdown voltage of the SiC chip 3.

Silicon carbide, silicon nitride, aluminum nitride, mullite, alumina and the like are suitable for the insulating ceramic outer cylinder 2.

As shown in FIG. 1, fins are provided around the entire circumference of the outer surface of the insulating ceramic outer cylinder 2 as ring-shaped projections for increasing the creepage distance.

After the semiconductor chip and other parts such as the SiC chip 3 are built in, the flanges are welded and sealed 14 together. Then, after the inside of the semiconductor element is replaced and filled with a non-oxidizing gas such as nitrogen gas using the internal gas replacement pipe 8,
Finally, the outer tip of the internal gas replacement pipe 8 is welded to completely seal the inside of the semiconductor element. Next, the metal portion exposed to the outside of this semiconductor element (common electrode, flange,
An electrode was attached to a brazing material, a pipe, and a welded portion, and electroplating with Ni (thickness: 5 to 10 μm) was performed in a plating bath, and then Pt plating 9 with a thickness of 2 to 5 μm was similarly applied. The Pt plating 9 was formed on the entire outer surface of the metal surface of the common electrode 1 and the flange member 6.

FIG. 2 is a cross-sectional view showing a semiconductor chip portion of the semiconductor device of this embodiment, which is taken along line A- in FIG.
The position A'corresponds to the position of the vertical cross section in FIG. Further, the SiC chip 3 is inserted into and supported by a ceramics insulating support body of an inner cylinder made of a square insulating ceramics, and its height is lower than the entire height with the intermediate electrodes 4 provided on both sides through the SiC chip 3. Is set. Further, the intermediate electrode 4 has different sizes on the upper side and the lower side, and by making the upper side smaller than the lower side, the contact between the both can be further enhanced.

(Embodiment 2) FIG. 3 is a vertical sectional view of a flat semiconductor device of the present invention. Multiple SiC diode chips 3
This is an example in which 1 and 32 are incorporated. Each of the SiC diode chips 31 and 32 has an anode electrode formed on one side of the SiC chip and a cathode electrode formed on the other surface thereof, and these electrodes serve as external electrodes of the semiconductor element. It is sandwiched between the common electrodes 12. In this embodiment, the intermediate electrode part used in the above-mentioned first embodiment is not used, and instead the protrusion 13 of the common electrode as shown in the figure is provided.
The cross-sectional structure in this embodiment is similar to that of FIG. 2, and seven SiC chips are arranged.

The pair of common electrodes 11 and 12 are externally insulated by an insulating ceramic outer cylinder 2, and the common electrode and the insulating outer cylinder have a low thermal expansion Fe-N.
The i-Co alloy flange members 61 and 62 form a hermetic structure in which the inside of the package is sealed and sealed. The flange members 61 and 62, the common electrodes 11 and 12, and the insulating outer cylinder 2 are airtightly joined with a silver brazing material (JIS BAg-8). Further, in this embodiment, a zirconium-copper alloy containing 0.1 to 0.15 wt% of Zr is used as the material of the common electrodes 11 and 12. The upper flange member 61 has a shape capable of expanding and contracting in the radial direction similarly to the first embodiment, and a flange of the same alloy is provided by brazing also on the upper portion of the insulating ceramic outer cylinder 2, and the common electrode 11 is The common electrode 12 has an appropriate length that can be expanded and contracted in the vertical direction and has a welded joint structure. A flange made of the same alloy is also provided by brazing on the lower part of the insulating ceramic outer cylinder 2, and has a structure capable of expanding and contracting in the radial direction.

The SiC chip 32 is inserted into a ceramic insulating member having a rectangular cylindrical cross section, and the contact with the SiC chip 32 is made by a protrusion provided on the upper common electrode 11 and mounted on the lower common electrode 12 by mounting. Done.

After the semiconductor chip and other parts are built in, the flanges are sealed by welding 15. After that, the inside of the semiconductor element is replaced with nitrogen gas by using the internal gas replacement pipe 8,
After filling, finally, the outer tip of the internal gas replacement pipe 8 is welded to completely seal the inside of the semiconductor element. Next, an electrode is attached to the metal part exposed to the outside of this semiconductor element, and the metal part (common electrode, flange, brazing material, pipe, welding, etc.) where the electric Pt plating 9 is exposed to the outside in the plating bath. Part) applied to the entire surface. Average thickness of plating film is 5μ
It was m.

(Embodiment 3) FIGS. 4 and 5 are enlarged vertical cross-sectional views of the common electrode of the high heat-resistant semiconductor element of the present invention and the outer cylinder portion of the insulating ceramics. The structure of any of the SiC chips, the intermediate electrode, and the ceramics insulating support is the same as in Example 1 or
Is constructed in the same way as. In this embodiment, a flange member is not used as a sealing member that connects the common electrode plate 1 and the outer cylinder 2 of insulating ceramics, and the common electrode plate 1 and the outer cylinder 2 of insulating ceramics contain Ag as a main component. An example of joining with a brazing material is shown. Also in this case, after completely hermetically sealing the inside of the semiconductor element, Pt plating 9 is applied to the entire surface of the metal portion (common electrode, brazing material, pipe, welded portion) exposed to the outside of this semiconductor element. There is. As an example of joining, FIG.
Then, it is a straight joint, and in FIG.
Is provided with a ring-shaped projection, and a groove is provided at a position corresponding to the inner peripheral surface of the insulating ceramic outer cylinder 2. As in FIG. 1, fins having ring-shaped protrusions are formed on a part of the outer circumference of the insulating ceramic outer cylinder 2.

In the embodiment, the outer shape of the common electrode or the package is round, but a quadrilateral semiconductor device is naturally possible, and in this case, the insulating outer cylinder is also preferably quadrangular. A desired shape may be selected in consideration of various other factors such as the manufacturing cost of the packaging material.

(Embodiment 4) FIG. 6 is a circuit diagram of one bridge of a self-excited converter for electric power using the high heat resistant semiconductor element of the present invention described in Embodiments 1 to 3. A SiC MOSFET 18 and a SiC diode 19, which are main conversion elements, are arranged in antiparallel, and n pieces are connected in series.
These MOSFETs and diodes represent flat semiconductor elements in which many SiC semiconductor chips are mounted in parallel. When the reverse conduction type SiC flat semiconductor device is used, the MOS in the figure
The FET 18 and the diode 19 are put together in one package.

The semiconductor element is a self-exciting converter used in an electric power system, a converter for a mill, a variable speed pumped hydro, a rolling mill, a substation facility, a substation facility for electric railway, sodium sulfur (NaS). It can also be used in converters such as battery systems.

Further, by using the highly heat-resistant semiconductor element having high reliability as described above, a higher performance power converter can be realized as compared with the conventional power converter using the Si semiconductor element. That is, the power converter using the semiconductor element of the present invention, compared with the case of using the Si semiconductor element, not only can achieve a significant reduction in loss and energy saving when the breakdown voltage is increased, and further Since it can be used at high temperatures, the burden of cooling etc. can be reduced,
Since the converter can be made compact, the cost can be significantly reduced.

[0046]

According to the present invention, a semiconductor device in which a plurality of semiconductor chips are incorporated in one flat package is targeted, and a highly heat-resistant semiconductor device which is highly reliable for use at a high temperature which has never been used in the past. Can be provided.

Further, by using the above-mentioned highly reliable SiC semiconductor element, it is possible to operate at a higher temperature than the converter using the Si semiconductor element which has been conventionally used in the field of high breakdown voltage and large current capacity. It is possible to provide a power converter capable of stable operation.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a semiconductor device of the present invention.

FIG. 2 is a cross-sectional view of a semiconductor device of the present invention.

FIG. 3 is a vertical sectional view of a semiconductor device of the present invention.

FIG. 4 is an enlarged vertical cross-sectional view of a common electrode of the present invention and an outer cylinder portion of insulating ceramics.

FIG. 5 is an enlarged vertical cross-sectional view of an outer cylinder portion of the common electrode and the insulating ceramics of the present invention.

FIG. 6 is a configuration circuit diagram of one bridge of a converter using the semiconductor device of the present invention.

FIG. 7 is a vertical cross-sectional view of a conventional semiconductor device.

[Explanation of symbols]

1, 11, 12, 21, 22, ... Common electrode, 2 ... Insulating ceramic outer cylinder, 3, 25, 31, 32 ... Semiconductor chip, 4, 23, 24 ... Intermediate electrode, 5 ... Ceramic insulating support, 6 , 61, 62 ... Flange, 7 ... Inert gas, 8
... Internal gas replacement pipes, 9, 91 ... Coating film,
10 ... Brazing material, 13 ... Common electrode protrusion, 14, 15 ...
Welded portion, 18 ... SiC MOSFET, 19 ... SiC diode, 20
... snubber 21, 21, 22 ... common electrode, 23, 24 ... intermediate electrode, 25 ... semiconductor chip, 26 ... resin outer frame,
27 ... Resin chip frame, 41 ... Heat-resistant insulating member.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Daisuke Takayama             3-3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture             Kansai Electric Power Co., Inc. (72) Inventor Katsunori Asano             3-3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture             Kansai Electric Power Co., Inc. (72) Inventor Yoshitaka Sugawara             3-3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture             Kansai Electric Power Co., Inc. F-term (reference) 5F047 JA02 JA11 JA20

Claims (19)

[Claims] 1. A pair of common electrode plates, a plurality of semiconductor chips having a heat resistance higher than that of silicon provided in parallel between the common electrode plates via an intermediate electrode, and an outer periphery between the common electrode plates. A joined insulating ceramic outer cylinder and an insulating ceramic inner cylinder for accommodating the semiconductor chips and the intermediate electrodes are provided, and the insulating ceramic outer cylinder is filled with a non-oxidizing gas. A high heat-resistant semiconductor element characterized in that 2. A pair of copper alloy common electrode plates, a plurality of semiconductor chips provided in parallel between the common electrode plates via an intermediate electrode, and joined to the outer periphery between the common electrode plates. A high heat-resistant semiconductor element comprising an insulating ceramic outer cylinder and an insulating ceramic inner cylinder accommodating each of the semiconductor chips and the intermediate electrode. 3. A pair of common electrode plates, a plurality of semiconductor chips provided in direct contact with the common electrode plates between the common electrode plates and provided side by side, and an insulating property bonded to the outer periphery between the common electrode plates. A high heat-resistant semiconductor element, comprising: a ceramic outer cylinder, wherein the insulating ceramic outer cylinder is filled with a non-oxidizing gas. 4. An insulating ceramic outer cylinder according to claim 1, wherein a ring-shaped fin for increasing a creepage distance is integrally provided on an outer peripheral surface of the outer cylinder. Heat-resistant semiconductor element. 5. The inner cylinder made of insulating ceramics according to any one of claims 1 to 4, wherein the inner cylinder is made of a straight cylinder, or the inner peripheral surface thereof is a quadrangular cylinder or a cylinder having the upper and lower shapes of the intermediate electrode. A high heat-resistant semiconductor element having: 6. The outer cylinder made of insulating ceramics according to claim 1, which is brazed to the common electrode plate via a metal flange or directly brazed to the common electrode plate. High heat resistance semiconductor device characterized by: 7. The high heat-resistant semiconductor element according to claim 1, wherein at least one of the metal flanges has a structure capable of expanding and contracting in a radial direction. 8. A high heat-resistant semiconductor element according to claim 1, wherein the insulating ceramic outer cylinder is provided with a supply port for supplying a non-oxidizing gas. 9. The surface of at least the common electrode plate exposed to the outside air, or at least the surface of the common electrode plate exposed to the outside air and the surface of the metal flange exposed to the outside air according to any one of claims 1 to 8. A high heat-resistant semiconductor element, characterized in that a film or a Pt layer for preventing oxidation due to outside air is provided on the inside. 10. A plurality of semiconductor chips are juxtaposed between the common electrode plates in a flat package whose inside is hermetically sealed by a pair of common electrode plates and an insulating ceramic outer cylinder. A high heat-resistant semiconductor element, wherein a Pt layer is formed on at least a surface of the electrode plate exposed to the outside. 11. The high heat-resistant semiconductor element according to claim 10, wherein the Pt layer is provided with a Ni layer as an underlayer. 12. A high heat-resistant semiconductor element according to claim 1, wherein the pair of common electrode plates are made of a precipitation hardening type copper alloy. 13. The pair of common electrode plates according to claim 1, wherein the pair of common electrode plates contains Cu as a main component, and Zr, Fe, Cr,
0.1-5 weight of at least one selected from Ti, Ag and Sn
High heat-resistant semiconductor element characterized by being made of an alloy containing 100%. 14. The high heat-resistant semiconductor according to claim 1, wherein the common electrode plate and an insulating ceramic outer cylinder are joined by a brazing material containing Ag as a main component. element. 15. The iron flange according to claim 1, wherein the metal flange has a coefficient of thermal expansion of 2 to 5 × 10 ⁻⁶ / ° C., an Fe-32 to 42 wt% Ni alloy, and Fe-30 ~ 4
A high heat-resistant semiconductor device, characterized by comprising one of 0 wt% Ni-5 to 20 wt% Co alloy. 16. A high heat resistant semiconductor element according to claim 1, wherein at least one of the semiconductor chips has a main current control function of controlling a main current by a control signal from the outside. 17. The high heat resistant semiconductor element according to claim 1, wherein the plurality of semiconductor chips are diodes. 18. A high heat-resistant semiconductor element according to claim 1, wherein the semiconductor chip is SiC, GaN or diamond. 19. A power converter characterized in that the main conversion element comprises the high heat-resistant semiconductor element according to any one of claims 1 to 18.