JPS5852859A - Insulated semiconductor device - Google Patents

Abstract

PURPOSE:To reduce the thermal strain caused in case of manufacture or during operation by a method wherein, in the semiconductor device where the metallic supporting members are electrically insulated but thermally and mechanically connected, the thermal expansion coefficient of the insulated members is made approximately coincident with that of the supporting members and the thermal expansion coefficient of composite metallic sheet is made coincident with that of semiconductor substrate. CONSTITUTION:The metallic supporting sheet 1 made of aluminum sheet is provided with the thermal expansion coefficient of 23.9X10<-6>/ deg.C while the composite resin film 2, an integrated film comprising fluorine resin films 221 and 222 on the both main surfaces of polyamide film 21 is also provided with the apparent thermal expansion coefficient of about 21X10<-6>/ deg.C approximateing to that of said metallic supporting sheet 1. The composite metallic sheet 3, a directly integrated sheet by cold rolled process comprising alloy sheets 321 and 322 made of 0.2mm. thick iron and 36% nickel is provided with the apparent thermal expansion coefficient of about 6.0X10<-6>/ deg.C set between the thermal expansion coefficient (3.5X10<-6>/ deg.C) of silicon as the material of the composite resin film 2 and the semiconductor substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides electrical insulation between an insulated semiconductor device, particularly a semiconductor substrate, and a metal support member on which the semiconductor substrate is placed,
The present invention relates to a thermally and mechanically connected semiconductor device.

Conventionally, a support member of a semiconductor device often served as one electrode of the semiconductor device. In recent years, structures have emerged that can electrically insulate all electrodes of a semiconductor device from a metal support member, thereby increasing the degree of freedom in circuit application of the semiconductor device. For example, in an insulated triac in which a bidirectional three-terminal thyristor (trybook) substrate is mounted on a ceramic plate and this ceramic plate is enclosed in a metal package, all electrodes of the triac are insulated from the package by the ceramic plate. It is snatched and pulled outside.

Therefore, even if the pair of main electrodes is electrically floating from the ground potential on the circuit, the package can be fixed to the ground potential regardless of the first electrode, making it easy to mount the semiconductor device. become.

Also, hybrid integrated circuit devices or semiconductor module devices (
In general, a hybrid IC (hereinafter collectively referred to as a hybrid IC) incorporates a certain set of electric circuits including semiconductor elements.
It is necessary to electrically insulate at least a portion of the circuit from metal parts such as supporting members or heat dissipating members of the hybrid IC. In a typical hybrid IC, the above-mentioned insulation is achieved by disposing an inorganic or organic insulating layer on a metal support member and assembling a predetermined electric circuit on this insulating layer. Such hybrid ICs are also insulated semiconductor devices.

On the other hand, in order to operate a semiconductor device safely and stably, it is necessary to effectively dissipate heat generated during operation of the semiconductor device to the outside of the package. This heat dissipation is normally accomplished by transferring heat from the semiconductor substrate, which is the heat source, to the air through the various members bonded to the substrate. In an insulated semiconductor device, this heat conduction path includes an insulating layer and an adhesive layer used for bonding the insulating layer and the semiconductor substrate.

The higher the voltage handled by circuits including semiconductor devices, or the higher the reliability required (stability over time, moisture resistance, heat resistance, etc.), the more perfect insulation is required. Explode. The above-mentioned heat resistance includes heat resistance when the temperature around the semiconductor device increases due to external causes, as well as when the semiconductor device handles a large amount of power and the heat generated in the semiconductor substrate increases.

If the heat generation within the insulated semiconductor device is relatively small and the withstand voltage and required reliability are not very high, there is no problem with using any material as the insulating layer or adhesive layer. .

However, when there are high demands on heat generation and reliability, the material composition of the insulating layer and the adhesive layer must be selected to meet those demands. In such cases, inorganic materials such as ceramics are usually selected as the insulating layer.
Also, a metal solder such as PB-8N solder is selected as the adhesive layer.

In that case, there were the following problems to be solved. In general, in an insulated semiconductor device, the semiconductor substrate is not placed on an insulating layer, but rather as a conductive path connecting the semiconductor substrate and an external power source, and a metal plate as a heat conduction path that effectively transfers heat generated in the semiconductor substrate to the insulating layer. Attached via. As this metal plate, a material having low resistance and high thermal conductivity such as copper is selected. However, the thermal expansion coefficients of this metal and the semiconductor substrate and insulating layer are significantly different. For example, the semiconductor is 7 recon.
When the insulating layer is alumina, the coefficient of thermal expansion is n3
．． 5X10-'/C, 6,3X10-'/IZ', while the coefficient of thermal expansion of copper is 18 X 10-'/C
And very thick.

The first problem is caused by this difference in thermal expansion coefficients when the semiconductor substrate and the insulating layer are soldered to the above-mentioned metal plate during the manufacture of an insulated semiconductor device.

That is, after laminating an insulating layer, a metal plate, and a semiconductor substrate through a solder layer, the temperature is raised to above the melting point of the solder, and then cooled to room temperature and soldered. Each member is fixed to each other at the freezing point. Thereafter, while fixed by solidified solder, each member contracts according to its own coefficient of thermal expansion. At this time, the amount of contraction of each member differs due to the above-mentioned difference in thermal expansion coefficient, and so-called thermal strain remains at the joint of each member. When thermal strain is relatively small, it is absorbed by the solder layer, which is the softest member, but when it is not absorbed, the joints and therefore the bonded members become deformed. In particular, deformation of the semiconductor substrate impairs the electrical characteristics of the semiconductor device, and also causes damage to the mechanically fragile semiconductor substrate and the risk of damaging the alumina plate.

The second problem occurs when using this type of semiconductor device.

That is, as the semiconductor device is energized and in rest operation, the above-mentioned junction is exposed to a high temperature state (approximately 100 to 150 C) and a low temperature state (approximately 100 to 150 C).
ambient temperature) is visited repeatedly. Each cycle of such repeated cycles of high and low temperatures is called a heat cycle.
Each member expands and contracts repeatedly according to its own coefficient of thermal expansion. Since each member is fixed to each other, the difference in the amount of expansion and contraction due to the difference in the coefficient of thermal expansion of each member appears as thermal strain applied to the solder layer, which is the softest member.

As the number of heat cycles increases, the solder layer gradually becomes brittle due to the periodic application of tensile strain and compressive strain as well as electrical changes, eventually leading to a thermal fatigue phenomenon. For example, cracks form in the solder layer, causing a decrease in adhesive strength and a decrease in electrical and thermal conductivity. Such a phenomenon is noticeable on the exposed end face of the solder layer.

In order to alleviate the first problem mentioned above, especially the stress applied to the semiconductor substrate, a metal plate for conduction and heat conduction is provided between the semiconductor substrate and the metal plate for conduction and heat conduction. It is known to interpose a piece of metal that is relatively similar to the blade, such as a piece of molybdenum. However, although such measures are useful in preventing deterioration of the semiconductor substrate, they are not effective in preventing deformation of other members. Also, the second
It is also powerless to solve the problems. Furthermore, the number of parts increases and brazing increases the number of parts, which causes problems in terms of cost and heat dissipation.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide an insulated semiconductor device which reduces thermal strain caused during manufacturing or operation and is free from the risk of deformation, deformation, or destruction of each member.

A feature of the present invention is that in an insulated semiconductor device, at least one composite resin film is placed on an insulating member made of a composite resin film having a laminated structure in which two or more resin layers of different types with different softening points are directly adhered to each other. Using seed resin film,
It has a structure in which a composite metal plate having a laminated structure in which two or more metal layers of different types are directly bonded to each other is bonded, and a semiconductor substrate is bonded directly onto the composite metal plate using a metal solder. More specifically, the overall thermal expansion coefficient (αl) of the above-mentioned insulating member is made to substantially match the thermal expansion coefficient (αP) of the metal package or supporting member, and the overall thermal expansion coefficient of the above-mentioned composite metal plate is The coefficient (αM) is set to a value between the thermal expansion coefficient αI of the insulating member described above and the thermal expansion coefficient (α8) of the semiconductor substrate described above.

In the present invention, the composite metal plate is used as a conductive path for the semiconductor substrate and for effectively transmitting heat generated in the semiconductor substrate to an insulating member and a heat dissipating means such as a package or supporting member, a heat dissipating fin, etc. arranged in conjunction with the insulating member. acts as a heat diffusion plate. , the thermal expansion coefficient of the composite metal plate as a whole is the apparent value of the composite metal plate, and when the composite metal plate generally consists of n layers, the thermal expansion coefficient of the material metal of each layer is α
1 (C-'), the longitudinal elastic modulus is El (Kg/101'
) and the thickness is approximated by the following equation (1).

Evening E+1+α.

Σ Eu+ −1 The composite resin film also serves as an electrically insulating carrier and an adhesive for mechanically integrating the composite metal plate and the package or support member. The thermal expansion coefficient of the composite resin film as a whole is the apparent resistance of the composite resin film. When a composite resin film generally consists of m layers, the thermal expansion coefficient of the material resin of each layer is αk (
71:””), the longitudinal elastic modulus is Eh (K9/mm2)
% thickness is fh (mm), r is approximated by the following equation (h).

ΣEhlhαh ΣEh'h −1 In the present invention, as will be described later, αM is set between α■ and αS, and α■ is set between αP and This is to make them approximately match. In particular, large hybrid ICs generate a lot of heat in the semiconductor substrate, so a metal plate with a large area is required.
Also, since multiple semiconductor substrates may be used, the area of the composite metal plate, and thus the bonding area with the insulating member and the bonding area between the insulating member and the package or supporting member, are larger than those of the semiconductor in a normal individual semiconductor device. The bonding area between the substrate and the support electrode is very large. In such cases, it has been found that it is effective to satisfy the above-mentioned expansion coefficient relationship in order to prevent thermal fatigue of the joint, that is, the adhesive material.

Hereinafter, the present invention will be explained in more detail by taking a hybrid IC as an example.

FIG. 1 shows a perspective view of a main part of a mixed XIC for controlling a 1.5 KVA class A current according to an embodiment of the present invention. In the figure, two composite resin films 2 are adhered side by side on a metal support plate 1, and composite metal plates 3 having substantially the same shape as the composite resin films 2 are respectively adhered to each composite resin film 2. ing. In FIG. 1, the adhesive between each member is not shown to simplify the drawing.

A circuit shown in FIG. 2 is assembled on the above-mentioned composite metal plate 3. That is, Darlington connected transistors 401 and 402, flywheel diode 40
3 are directly soldered onto the composite metal plate 3, respectively. Further, a snubber chip capacitor 404 and a chip resistor 405 connected in series with the snubber chip capacitor 404 are mounted. Each circuit element is connected by a wiring wire or strip 440 and a wiring metal piece 430 as in the circuit shown in FIG. External terminals 4101, 4102, and 4103 are provided at one end of the composite metal plate 3 (the left end in the figure). The external terminal 4101 is directly on the composite metal plate 3,
2 is installed via a metal piece 430 for wiring, and 4103 is installed via an insulating resin film 420 and a metal piece 430 for wiring bonded thereon. Further, at the end of the composite metal plate opposite to the external terminal shown in FIG.
It is provided on the wiring metal piece 430 that is glued on top.

What is important in this example is that the composite resin film 2
, the composite metal plate 3 is used, the size of the composite metal plate 3 is approximately the same as the composite resin film 2, and all the circuit elements are placed on it, and the semiconductor substrate ( The transistors 401 and 402 and the diode 403) are directly soldered to the composite metal plate 3, and at least one resin layer of the composite resin film 2 insulates and integrates the metal support plate 1 and the composite metal &3. This is a point that is becoming more and more common.

These points will be explained below.

FIG. 3 schematically shows a cross section of only the portion from the metal support plate 1 to the composite metal plate 3 of the structure of this embodiment. In the figure, the metal support plate 1 has a thickness of 2Wan.

It is an aluminum plate with a width of 61 mm and a length of 105 mm and a coefficient of thermal expansion of 23.9 x 10''/c. Fluororesin films 221 and 222 with a thickness of 125 μm are directly integrated by a rolling method without intervening other members.The film has a width of 28 cm and a length of 33 cm. The apparent coefficient of thermal expansion of this composite resin film 2 is about 21×10''/C, which is close to that of the metal support plate 1.

On one main surface of the metal support plate 1, two composite resin films 2 are adhered with a fluororesin film 221.

On each composite resin film 2, a fluororesin film 222 having the same composition as the fluororesin film 221 is placed on the composite metal plate 3.
Due to this, it is glued.

This composite metal plate 3 is made by directly integrating iron-36% nickel alloy plates 321 and 322 with a thickness of 0.2 mm on the two sides of a copper plate 31 with a thickness of 2 cm by cold rolling, The width is 25 sho and the length is 30 sho. The apparent coefficient of thermal expansion of this composite metal plate 3 is approximately 6, OX 10-'/C, and the coefficient of thermal expansion of the laminated resin film 2 (21X 10-'/C).
ll:') and the coefficient of thermal expansion of silicon, which is the material of the semiconductor substrate (3.5X 10-'/l'?).

The composite resin film 2 in this embodiment is designed so that its apparent coefficient of thermal expansion is as close as possible to -tn of the metal support plate 1 in order to prevent excessive thermal strain from occurring during hybrid IC manufacturing or operation. I'm in the middle of the day.

Further, for the same purpose, the composite metal plate 3 has an apparent coefficient of thermal expansion smaller than that of the composite resin film 2 and significantly higher than that of the silicone plate.

The apparent coefficient of thermal expansion of the composite resin film can be adjusted by changing the type and thickness of the resin film used as a material, or by adding glass fiber or the like to the resin layer. For example, the thermal expansion coefficient of a polyvaraponic acid film is 42×10′-′/?The thermal expansion coefficient of a C1 fluororesin film is 55×10′-′/? ”: However, in a film with 50% glass fiber added, it was n15X1.
0″″'/l:'.

It changed to 2 ox 10-6/C.

The apparent coefficient of thermal expansion of the composite metal plate can be adjusted by changing the type of metal layer used as the raw material or the composition ratio in the case of an alloy material. It can also be adjusted by changing the thickness of each metal layer. Further, it can be adjusted by changing the rolling rate when forming the composite metal plate by rolling.

For example, an iron-36% nickel alloy plate (thickness 0.1 mm
The apparent coefficient of thermal expansion of a composite metal plate with copper (thickness 0.1 yen) directly bonded to the amphiphilic surface is 10.9X10'
-67C, and in the case of iron-29% nickel-17% cobalt alloy, the coefficient of thermal expansion when not rolled is 5.5.
X 10"'/ll:' is the rolling rate of 60%
(Rolling conditions where the thickness is 40% of that before rolling) is 5 x 10
""/Tll' changed to 6X10-'/U at a rolling rate of 90%.

The pair of outer metal layers in the composite metal plate 3 were selected not from the viewpoint of electrical and thermal conductivity, but from the viewpoint that the thermal conductive coefficient was similar to that of the silicon semiconductor substrate. In addition, the middle layer, on the contrary, was selected mainly from the viewpoint of having high electrical and thermal conductivity, and was made thicker than the pair of outer metal layers in order to increase the electrical and thermal conductivity of the composite metal plate as a whole. .

The pair of outer resin films in the composite resin film 3 have a softening temperature lower than that of the intermediate film, and are bonded to metal at a relatively low temperature, rather than having electrical insulation properties and thermal expansion coefficients close to those of the metal support plate. F' was selected from the viewpoint that the outer resin film has a large elongation rate of 350%.

On the other hand, the intermediate resin film was selected primarily from the viewpoint that it could reliably maintain electrical insulation and that its coefficient of thermal expansion was similar to that of the metal support plate 1. In this way, the composite resin film as a whole is configured to maintain reliable electrical insulation, precise adhesion, and thermal fatigue resistance due to heat cycles.

According to this embodiment, the conventional structure is used, that is, a copper thermal diffusion plate is soldered onto an alumina plate that is soldered onto a package or support member, and a semiconductor substrate is bonded thereon via a molybdenum piece. Compared to a hybrid IC having a stripped structure, heat cycle resistance could be improved without substantially reducing heat dissipation to the point where it becomes a problem. This effect became more remarkable as the area of the composite resin film and therefore the area of the composite metal plate (the area of the heat control diffusion plate in the conventional example) increased.

An example thereof will be explained in detail with reference to FIG. Figure 4 shows
The area of one composite resin film of the hybrid IC having the structure (A) of this embodiment or the area of one alumina plate of the hybrid IC having the above-mentioned conventional structure and occurrence of failure of the hybrid IC after application of a predetermined heat cycle It is a graph showing the relationship between rates. The heat cycle was from -5511r to +150C, and the number of times was 150. According to Fig. 4, the failure rate is 0% for both A and B when the area of the composite resin film or alumina plate is up to about 500 mm2, but when the area exceeds about 500 mm2,
While the failure rate increases rapidly in case B, it is still 0% in case 1A. Note that the failure referred to here mainly refers to the occurrence of clutter or partial peeling of a resin film that also serves as a solder layer or adhesive.

Also, in Fig. 4, if the area is about 500 mm2t, it is A.

It seems that there is no difference with B, but even in this ode,
A was superior to B in terms of the degree of warpage of the metal support plate. That is, after the hybrid IC was completed, in A, the warpage in the longitudinal direction of the metal support plate l was approximately 10 μm in height;
In B, it was about 0.33 to 1.5 k.

This kind of warping occurs when a frame or lid made of Evokin resin or the like is installed around the outer periphery of the metal support plate, which creates a gap between the frame or lid and the metal support plate, resulting in poor sealing performance, moisture resistance, and corrosion resistance. Unfavorable in this respect. Furthermore, when attaching the metal support plate to an external heat dissipation fin or the like, if the metal support plate is warped, a gap will be created and the heat dissipation performance will be reduced, which is undesirable. This embodiment does not suffer from the drawbacks described above.

In this embodiment, it is preferable to use a metal plate having a coefficient of thermal expansion similar to that of the composite resin film 2 as the metal support plate 1 in order to improve the reliability of the hybrid IC. However, from the viewpoint of protecting the semiconductor substrate directly adhered to the composite metal plate 3 and preventing deterioration of the brazing material between the semiconductor substrate and the composite metal plate 3 (which affects the current conduction heat dissipation characteristics of the semiconductor substrate), , and from the viewpoint that the resin film as an adhesive has a high elongation rate and follows the expansion and contraction of the metal support plate 1 well, metals other than aluminum, such as copper plates, nickel plates, copper-zinc alloys, etc., can be used as the metal support plate 1. can be used.

Further, when soldering the composite metal plate 3, it is preferable to form a metal film of nickel or the like on the surface by plating or the like in order to improve solderability.

Next, another embodiment of the present invention will be described using FIG. 5. In Fig. 5, an insulating member 2 made of a composite resin film is a single nfC film 1 that is continuously integrated, and a support member 1 made of aluminum (width 61 mm x Length 105■ x thickness 2B)
A plurality of composite metal plates 3 are bonded to the other main plane side. For example, a semiconductor circuit as shown in FIG. 2 is assembled on the composite metal plate 3, but its description is omitted in this embodiment. In this embodiment, the insulating member 2 has a width of 60 mm and a length of 33 mm, and the composite metal plate 3 has a width of 25 mm.
The length is 30 mm, and both of the blades are of a laminated structure having the same material and thickness as those shown in Fig. 1.

According to this embodiment, since the insulating member 2 is made of a single film, the number of parts and man-hours can be reduced. This effect is due to the fact that the coefficient of thermal expansion of the insulating member 2 is close to that of the supporting member, and that the insulating member 2 is bonded with a resin film made of a resin having a high elongation rate.

Next, various modifications of the present invention will be illustrated.

The present invention can be implemented in various embodiments other than the embodiments described above.

First, the material resins constituting the composite resin film as an insulating member include, in addition to polyimide and fluororesin, polyester resin, polybalapic acid resin, silicone resin, biroline polyimide precursor resin, and polyamideimide:
Resins such as epoxy-novolac resins, nitrile rubber-phenolic resins, epoxy-polyamide resins, epoxy-acrylic resins, or other resins containing additives such as glass fiber and alumina powder can be used. In this case, the gantry resin film may have a laminated structure of four or more layers.

As the composite metal plate, for example, a copper plate in which iron-nickel alloy plates or iron-nickel-cobalt alloy plates of various composition ratios are directly integrated on both sides can be used. In addition, in the above structure, instead of the copper plate, metals such as nickel, zinc, aluminum, gold, silver, palladium, etc., which have better electrical and thermal conductivity than the alloy plates located on both sides, or alloys mainly composed of these metals can be used. can be used. In addition, the arrangement of the three-layer structure described above is changed, and an iron-nickel alloy plate, etc. is used in the center of the three layers, and copper plates, etc., which have better electrical and thermal conductivity than the central layer, are directly integrated on both sides. It's okay to have one. Furthermore, 3
The structure is not limited to a layered structure, and may be a two-layered structure or a structure of four or more layers. However, in the case of a two-layer structure or a three-layer structure,
In order to prevent the composite metal plate from warping due to the bimetallic action caused by the difference in thermal expansion coefficient, even if it has a structure with more than one layer,
Care should be taken in selecting the material and thickness of each layer.

In addition to the above-mentioned cold rolling method, the composite metal plate can be manufactured by hot rolling, or by forming another metal layer on the main surface of one metal plate by vapor deposition, sputtering, vapor growth, etc. A method such as that can be used.

In addition to solder with a lead-60% tin composition, for example, solder with a lead-5% tin composition, or these solders, etc. A material containing silver, bismuth, etc. can be used as the i component. Its thickness is also 0.1 m
It is not limited to n, but may be thicker or thinner than n. Generally, the thicker the solder layer, the better it absorbs thermal strain, but since the thermal conductivity of the solder itself is not as high as shown in the figure above, the heat dissipation of the hybrid IC is reduced. Another aspect of the present invention is that by using a composite metal plate as in the above embodiment, the occurrence of thermal distortion can be suppressed, thereby effectively reducing the thickness of the solder layer and improving the heat dissipation performance of the hybrid IC. This is the effect of

Generally, the thermal conductivity of resin films is lower than that of ceramics such as alumina, but the resin film, which also serves as an adhesive for composite resin films, softens at relatively low temperatures and increases fluidity, making it possible to achieve dense adhesion, as well as elasticity. Since the composite resin film is rich in heat, it is possible to integrate a large-area metal plate, and as a result, the composite resin film can be made thin and heat can be spread and transmitted, so that the heat dissipation performance of the hybrid IC does not deteriorate significantly. This is also an effect of the present invention.

Next, in the type and (b) configuration of the semiconductor substrate placed on the composite metal plate, any semiconductor element (semiconductor element other than silicon, such as germanium, gallium arsenide, gallium phosphide, silicon carbide, etc.) Needless to say, the method can be applied to circuits (including those using the same) and circuits.

As described above, the present invention is effective in obtaining an insulated semiconductor device that is free from the risk of deformation, degeneration, or destruction of each member due to thermal strain.

[Brief explanation of the drawing]

1 to 3 are diagrams showing the configuration of a hybrid IC according to an embodiment of the present invention, and FIG. 4 is a diagram showing the configuration of a hybrid IC according to another embodiment of the present invention
A characteristic diagram showing the relationship between the adhesion area of the composite resin film or the adhesion area of the inorganic insulating member of the conventional example and the failure rate of the hybrid IC; FIG. 5 is a cross section of the main part of yet another embodiment of the present invention. FIG. ■...Metal support member, 2...Composite resin film, 3
...Representative: Patent Attorney Akira Takahashi, 9th Akira Hatsubo

Claims (1)

[Claims] 1. A composite resin film having an n-fold laminated structure in which two or more resin films with different softening points are directly bonded together, and at least one resin film of this composite film is used to place a support member on a support member. an insulating member supported on the insulating member and at least one resin film of the composite film on the insulating member, and an adhesive layer n1 and a second metal layer of different types are directly adhered to each other n*
a laminated metal plate having a laminated structure; and at least one semiconductor substrate electrically conductively adhered to a surface of the composite metal plate opposite to the insulating member, the thermal expansion coefficient of the insulating member as a whole; approximates the coefficient of thermal expansion of the supporting member, and the overall coefficient of thermal expansion of the composite metal is selected between the coefficient of thermal expansion of the insulating member and the coefficient of thermal expansion of the semiconductor substrate. Insulated semiconductor device. 2. The insulated semiconductor device according to claim 1, wherein the supporting member is made of metal. 3. The insulated semiconductor device according to claim 1, wherein the supporting member and the composite metal plate are bonded together using a resin film having at least a higher elongation rate than the supporting member and the composite metal plate. 4. In claim 1, the shape of the main surface of the composite metal plate is approximately equal to or smaller than the shape of the main plane of the insulating member, and a plurality of circuit elements are bonded on the composite metal plate. An insulated semiconductor device characterized in that: 5. An insulated semiconductor device according to claim 4, characterized in that two or more of the composite metal plates are adhered onto the insulating member.