JP2000049198A - Pressure welding type semiconductor device and producing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain high reliability of a semiconductor device by keeping the uniformity of a temperature distribution and the uniformity of a pressure distribution of a semiconductor substrate, and also to improve the characteristics by remarkably reducing a thermal resistance. SOLUTION: Thermal buffer plates 12a, 12c are provided to contact with both of the sides of a semiconductor device where the electrodes 16a, 16c are provided on both of the main sides of a semiconductor substrate 15. The thermal buffer plates 12a, 12c are individually fixed and bonded with post electrodes 13a, 13c which are placed on the outer side of the thermal buffer plates 12a, 12c. Grooves 14a, 14c are formed in sides 131a, 131c which face junctions 130a, 130c where the thermal buffer plates 12a, 12c are bonded with the post electrodes 13a, 13c individually.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-contact type semiconductor device with reduced thermal resistance and a method for manufacturing the same.

[0002]

2. Description of the Related Art The structure of a conventional pressure contact type semiconductor device is shown in FIG.
As shown in FIG. 7, a semiconductor element formed by providing electrodes 6a and 6c on the main surface of a silicon semiconductor substrate 5, and molybdenum (M
o) or a thermal buffer plate 2a made of tungsten (W),
2c, and post electrodes 3a, 3c provided outside the thermal buffer plates 2a, 2c.

[0003] These members are housed in a cylindrical container 8 made of an insulating material, and the cylindrical container 8 is joined to the post electrodes 3a, 3c via metal flanges 9a, 9c. The inside of 8 is sealed with an inert gas. On the other hand, a water-cooled heat sink plate for removing heat generated from the semiconductor element is provided outside the post electrodes 3a and 3c, and the members are brought into contact by pressing the semiconductor device 1 from outside the heat sink. .

Although the semiconductor device 1 generates heat due to a large current flowing during operation, the heat-resistant temperature of the semiconductor element is at most 200.
Since the temperature is about ° C., a major technical problem is how to remove heat from heat sinks located above and below the semiconductor element and how to suppress the temperature rise of the semiconductor element. In particular,
The amount of heat generated tends to increase with the increase in size and capacity of semiconductor elements, and it can be said that cooling of semiconductor elements is extremely important for practical use of large-size and large-capacity semiconductor devices in the future.

On the other hand, the pressure contact type semiconductor device has a laminated structure as shown in FIG. 17, and a contact thermal resistance always exists at a contact portion of each member. It is known that this contact thermal resistance depends on the pressure, and tends to decrease as the pressure increases.

For this reason, a press-contact type semiconductor device is generally 50
It is necessary to apply pressure from both upper and lower directions at a pressure of not less than kgf / mm ² , and therefore a large-sized pressurizing mechanism is indispensable. In addition, even when the pressure is applied under such pressure, the contact thermal resistance does not become zero, and the thermal resistance of the component itself exists. Therefore, a large cooling unit for cooling the semiconductor device is indispensable. Has become.

[0007]

Some proposals have been made on methods for reducing the pressure and thermal resistance of such a semiconductor device. For example, in Japanese Patent Application Laid-Open No. 5-304179, stress is made uniform by processing concentric grooves in a thermal buffer plate in contact with a semiconductor element. According to such a method, the stress can be certainly made uniform, but the thermal resistance cannot be reduced at all. Rather, cooling is insufficient in the vicinity of the semiconductor element in contact with the groove formed in the thermal buffer plate, causing a local temperature rise of the semiconductor element, and the element is likely to be damaged.

In Japanese Patent Application Laid-Open No. 8-167625, a thermal buffer plate is fixedly attached to the front and back surfaces of a semiconductor element to reduce the pressing force and the thermal resistance. According to this method, the contact thermal resistance between the semiconductor element and the thermal buffer plate becomes almost zero, which is effective for reducing the thermal resistance of the semiconductor device.
However, since the thermal expansion coefficient is different between the heat buffer plate and the semiconductor element, heating at the time of joining the heat buffer plate and the semiconductor element,
Thermal stress is generated by a thermal cycle during use, and a brittle semiconductor element is likely to be broken.

In order to reduce the thermal stress acting on such a semiconductor element, it is effective to reduce the thickness of the thermal buffer plate as well as the bonding temperature. However, there is a limit to a decrease in the joining temperature, and in practice, it is necessary to reduce the thickness of the thermal buffer plate to cope with it.

As a result, the externally applied pressure acting on the semiconductor substrate can be made uniform by the heat buffer plate having high rigidity, but the rigidity of the heat buffer plate is reduced by the thin heat buffer plate. However, there is a high possibility that the non-uniform pressure acts on the semiconductor substrate and the semiconductor element is damaged.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to maintain high reliability of a semiconductor device by maintaining uniformity of temperature distribution and pressure distribution of a semiconductor substrate, An object of the present invention is to provide a press-contact type semiconductor device capable of significantly reducing resistance and a method of manufacturing the same.

[0012]

According to the present invention, there is provided a press-contact type semiconductor device and a method of manufacturing the same, wherein electrodes are provided on both main surfaces of a semiconductor substrate to form a semiconductor element, and thermal buffer plates are provided on both sides of the semiconductor element. Further, in a press-contact type semiconductor device in which a post electrode is provided outside the heat buffer plate and pressurized and energized from above and below via the post electrode, the heat buffer plate and the post electrode are joined and the heat buffer of the post electrode is heated. It is characterized in that a groove is formed on the surface facing the joint surface with the plate.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the press contact type semiconductor device of the present invention will be described.

(Embodiment 1) FIG. 1 is a sectional view of a press-contact type semiconductor device. First, electrodes 16a, 1a are provided on both main surfaces of a disk-shaped silicon semiconductor substrate 15 constituting a thyristor.
6c is provided to constitute a semiconductor element. Disk-shaped thermal buffer plates 12a, 12 made of molybdenum (Mo) or tungsten (W) are provided on the upper and lower surfaces of the semiconductor element.
c is placed in contact with the electrodes, and
The semiconductor device 10 is constituted by providing disk-shaped post electrodes 13a and 13c made of, for example, copper (Cu) outside the a and 12c. The heat buffer plate 12
The a and 12c and the post electrodes 13a and 13c are fixedly joined to each other by solder or the like to form a heat buffer / post electrode assembly.

These members are housed in a cylindrical container 18 made of an insulating material, and the cylindrical container 18 is joined to the post electrodes 13a, 13c via metal flanges 19a, 19c fixed to the edges. The inside of the cylindrical container 18 is sealed with an inert gas. Reference numeral 16b denotes a gate electrode pad, which is taken out of the inert gas inlet by a lead 16d. The inlet is provided with a sealing tube 18a and sealed off by chip-off.

The post electrodes 13a and 13c and the heat buffer 12
The post electrodes 13a, 13c are provided on opposing surfaces 131a, 131c facing the joint surfaces 130a, 130c with the a, 12c.
The grooves 14a and 14c are cut in the thickness direction of the groove c.
4a and 14c, the thermal stress generated in the heat buffer plate / post electrode assembly when the heat buffer plates 12a and 12c are fixedly joined to the post electrodes 13a and 13c or when a heat cycle is applied during use. And reduce deflection.

As shown in FIG. 2, this post electrode 13
a, groove 1 formed on opposing surfaces 131a, 131c of 13c
The shapes of the grooves 4a and 14c are desirably symmetrical. From such a viewpoint, the grooves 14a and 14c are formed in a lattice shape on the entire opposing surfaces 131a and 131c of the post electrodes.
During use, the heat sink plates 30a, 30c are pressed against the facing surfaces 131a, 131c.

Note that, as shown in FIG.
a and 13c are joined to the insulating container 8 via the flanges 19a and 19c, and the interior of the semiconductor device 10 is sealed. Therefore, the grooves 14a and 14c are formed in the post electrodes 13a and 13c.
It is necessary not to reach the outer periphery of 13c. When the grooves 14a, 14c reach the interface with the thermal buffer plates 12a, 12c, stress concentration occurs at the groove corners at the joint interface between the post electrodes 13a, 13c and the thermal buffer plates 12a, 12c. Therefore, it is preferable that all the grooves 14a and 14c are formed inside the post electrodes 13a and 13c.

(Embodiment 2) In this embodiment, as shown in FIG. 3, the joint surfaces 130a of the post electrodes with the heat buffer plate are formed.
Concentric grooves 141 are formed in outer facing surfaces 131a and 131c facing 130c. Since a plurality of concentric grooves are formed around the central axis of the semiconductor device, thermal stress acts uniformly on the entire surface, and uneven distribution of stress can be prevented.

(Embodiment 3) FIG.
A post electrode having an unstructured structure for further reducing the rigidity of the post electrodes 13a and 13c is shown, and a ring-shaped region 21 on the outer periphery of the post electrodes 13a and 13c and lattice grooves 14a and 14 at the center.
A concentric ring-shaped groove 142 is formed between the lattice-like regions 22 formed by c.

(Embodiment 4) FIGS. 13 to 16 illustrate a method of manufacturing a press contact type semiconductor device according to the present invention. First, as shown in FIG. 13, a thermal buffer plate 12 made of tungsten or molybdenum and a post electrode 13 made of copper are joined. At this time, a lattice-shaped groove 14 as shown in FIG. 2 or a concentric groove 14 as shown in FIG. 3 is formed on the opposing surface 131 of the joint surface 130 of the post electrode 13 with the thermal buffer plate 12 by machining or the like. It is formed in advance.

As the joining method, there are brazing joining, diffusion joining, solder joining and the like. From the viewpoint of suppressing thermal stress and bending deformation, the joining temperature is preferably as low as possible.
Further, in order to reduce the amount of deflection of the joined thermal buffer plate / post electrode assembly, it is also effective to press the thermal buffer plate 12 and the post electrode 13 from above and below with a pressing device 24 or the like when joining.

The thermal buffer plate obtained by such a method /
The post electrode assembly is slightly deformed (bent) due to a difference in thermal expansion between the thermal buffer plate 12 and the post electrode 13, and
An oxide film causing thermal resistance is formed on the surface. Therefore, the thermal buffer plate / post-electrode assembly obtained in FIG. 13 is machined to ensure the parallelism of the upper and lower surfaces, and the surface of the thermal buffer plate in contact with the semiconductor element and the surface of the post electrode in contact with the heat sink are: As shown in FIG. 14, the oxide film is removed and the surface roughness is adjusted to obtain a heat buffer plate / post electrode assembly 17.

On the other hand, as shown in FIG. 15, a cylindrical container 18 made of an insulating ceramic for housing a semiconductor element and a heat buffer plate / post electrode assembly 17 has metal flanges 19a and 19c on its upper and lower surfaces. Join.

Thereafter, as shown in FIG. 16, the semiconductor element and the heat buffer / post electrode assembly 1 are placed in a cylindrical container 18.
7 are laminated, and the ends of the post electrodes 13 and the metal flanges 19a and 19c joined to the cylindrical container 18 are hermetically welded.

At this time, in order to suppress the temperature rise of the semiconductor element and the heat buffer plate / post electrode assembly 17, the heat input during welding is made as small as possible, and the upper and lower surfaces of the post electrode are cooled as necessary. Is valid.

Electron beam welding and laser beam welding are suitable as welding methods with low heat input during welding. As shown in FIG. 1, post electrodes 13a and 13c are suitable for welding. And metal flange 19
As shown by the arrow K in FIG. 16, the welding direction with the a and 19c is preferably the vertical direction (center line direction) of the semiconductor device. In the press-contact type semiconductor device configured as described above,
When the contact thermal resistance between the members constituting the semiconductor device 10 is measured in detail, the thermal buffer plates 12a and 12c and the post electrode 1
3a and 13c have the largest contact thermal resistance, and as shown in FIG.
By integrating the a and 12c and the post electrodes 13a and 13c by bonding, the contact thermal resistance of the semiconductor device can be significantly reduced as shown in FIG. 5 and described later.

However, in general, the coefficient of thermal expansion is greatly different between the heat buffer plate and the post electrode like molybdenum and copper.
In the case of a large semiconductor device, cracks may occur at the interface between the heat buffer plate and the post electrode due to the heat applied during bonding and the load of the heat cycle during use. Is easily deformed.

Then, a bonding test was performed on various shapes of the bonding surface to evaluate the presence or absence of cracks and the thermal deformation. As a result, the embodiment of the present invention was confirmed as shown in FIGS. , 13c and thermal buffer plates 12a, 1
By forming grooves 14a and 14b on the surface facing the bonding surface with 2c and reducing the rigidity of post electrodes 13a and 13c, it is possible to reduce thermal stress and deflection (warpage).

As a member for forming the post electrodes 13a and 13c, a metal material having low rigidity and easily causing plastic deformation is suitable. That is, the post electrodes 13a, 13c
When there is no groove 14a, 14c in the heat buffer plate 12a,
Due to the difference in thermal expansion between the post electrode 12c and the post electrodes 13a, 13c, a large thermal stress and deflection occur in the heat buffer / post electrode assembly.
The post electrodes 13a and 13c are plastically deformed by forming the a and c and reducing the rigidity, so that the thermal stress and the amount of deflection can be reduced.

In the above-mentioned Japanese Patent Application Laid-Open No. 5-304179, since a concentric groove is formed on the surface of the thermal buffer plate in contact with the semiconductor element which generates heat, there is a concern that the semiconductor element may be overheated near the groove. According to the present embodiment, since the groove is formed on the opposite surface of the post electrode located outside the heat buffer plate in contact with the semiconductor element, heat generated in the semiconductor element is diffused in the heat buffer plate, and the semiconductor formed by the groove is formed. There is no worry about overheating of the cord.

Further, in Japanese Patent Application Laid-Open No. 8-167625, since a fragile semiconductor element and a thermal buffer are joined, it is necessary to reduce the thickness of the thermal buffer in order to reduce thermal stress acting on the semiconductor element. However, in the present embodiment, since the heat buffer plate and the post electrode are integrated by fixed bonding, it is possible to increase the thickness of the heat buffer plate, and the non-uniform external pressing force acts on the semiconductor element. Also, damage to the semiconductor element can be avoided.

FIG. 5 shows the effect of this embodiment.
The structure of the semiconductor device according to the first embodiment of the present invention shown in FIG. 1 is simulated, and a molybdenum thermal buffer having a diameter of 50 mm and a thickness of about 2 mm is placed above and below a semiconductor element having a diameter of 50 mm and a thickness of about 1 mm. The heat buffer plate / post electrode assembly in which the plates 12a and 12c and the pure copper post electrodes 13a and 13c each having a diameter of 50 mm and a thickness of about 20 mm are laminated, and externally pressurized at a pressure of 50 kgf / mm ² . The result of measuring the contact thermal resistance of the semiconductor device 10 in the case is shown.

FIG. 5 simulates the conventional structure shown in FIG. 17 as a comparative example, in which molybdenum heat buffer plates 2a and 2c having a diameter of 50 mm and a thickness of about 2 mm are provided.
The results of measuring the contact thermal resistance of the semiconductor device when the post electrodes 3a and 3c made of pure copper having a thickness of about 20 mm are laminated without being joined and externally pressurized at a pressure of 50 kgf / mm ² are also shown. ing.

Referring to FIG. 5, according to the present invention, the heat buffer plates 12a,
It can be seen that the contact thermal resistance of the semiconductor device 10 can be reduced to about 1/6 of the related art by integrating the post electrode 12c with the post electrodes 13a and 13c.

FIG. 6 simulates a large-sized and large-capacity semiconductor device, in which a molybdenum heat buffer plate having a diameter of 130 mm and a thickness of 2 mm and a copper post electrode having a diameter of 130 mm and a thickness of 20 mm are joined at 800 ° C. 4 shows the results of analyzing the thermal stress and the amount of deflection when cooled to room temperature.

In FIG. 6, the amount of deflection when the copper post electrode is directly bonded without forming a groove is used as a reference (conventional example), and the post electrode of FIG.
When a lattice-shaped groove (depth 10 mm, width 1 mm) is machined at an mm pitch, and a concentric groove (depth 10 mm, width 1) at a pitch of 20 mm as shown in (Embodiment 2) shown in FIG.
mm), and after machining grid-like grooves (depth 10 mm, width 1 mm) at a pitch of 20 mm in the copper post electrode shown in (Embodiment 3) shown in FIG. The amount of deflection in the case where a concentric groove was machined between the inner lattice region and the inner lattice region was shown in comparison with the conventional example.

FIG. 6 shows that the amount of deflection of the post electrode / thermal buffer plate assembly can be significantly reduced by forming a groove on the surface of the post electrode opposite to the surface where the thermal buffer plate is bonded. It is to be noted that the lattice-shaped groove shown in FIG. 2 (Embodiment 1) has a larger deflection amount than the concentric groove shown in FIG. 3 (Embodiment 2) because of the post electrode. This is because the rigidity of the post electrode greatly affects the amount of deflection of the post electrode / heat buffer plate assembly, because the rigidity of the post electrode / heat buffer plate assembly is high. It is clear from.

FIG. 7 shows the results of an experiment conducted to select materials to be used for the heat buffer plate and the post electrode, and shows the results of measuring the thermal resistance and the elastic modulus of a typical metal material.

For both the thermal buffer plate and the post electrode, a material having a small electric resistance is suitable for suppressing heat generation, and a material having a small thermal resistance is used for cooling the heat of the semiconductor element by the heat sink. preferable.

From this viewpoint, stainless steel (SUS) or nickel (Ni) is not suitable as a material used for the heat buffer plate or the post electrode. As shown in FIG. Aluminum (Al), silver (Ag),
Gold (Au), molybdenum (Mo) or tungsten (W) is suitable.

As described above, in the thermal buffer plate, it is important that the elastic coefficient is large in order to uniformly transmit the external pressure to the semiconductor element. FIG. 7 shows that copper, aluminum, silver, and gold are not suitable as materials satisfying such requirements, and tungsten and molybdenum are suitable.

On the other hand, as the post electrode material, a material having a small elastic coefficient is preferable in order to reduce the thermal stress and strain generated at the time of joining with the thermal buffer plate. Is not suitable, and copper, aluminum, silver, and gold are suitable. Among them, copper and aluminum are considered optimal from the viewpoint of cost.

FIG. 8 shows the relationship between the size of the lattice formed on the joint surface of the post electrode and the heat buffer plate and the amount of deflection of the heat buffer plate / post electrode assembly. In FIG. 8, the diameter is 130 mm,
Molybdenum thermal buffer 2mm thick and 130m diameter
This is the result of measuring the amount of deflection of the heat buffer plate / post electrode assembly when the copper post electrode having a thickness of 20 mm and a thickness of 20 mm was joined at 800 ° C. and then cooled to room temperature. The vertical axis in FIG. 8 is a plot of the ratio based on the amount of deflection generated when no groove is formed in the post electrode. According to FIG. 8, the amount of deflection generated in the thermal buffer plate / post-electrode assembly tends to decrease as the size of the grid becomes smaller.
It can be seen that it can be reduced to / 2 or less. In consideration of the parallelism between the front and back surfaces of the heat buffer plate / post electrode assembly during use, it is desirable that the amount of flexure generated is small, and the size of the grid formed on the post electrode is preferably 20 mm or less.

FIG. 9 shows the depth of the grid (ratio of grid depth / post electrode thickness) formed on the joint surface of the post electrode with the thermal buffer and the amount of deflection generated in the thermal buffer / post electrode assembly. The relationship is shown below. In FIG. 9, the diameter is 130 mm and the thickness is 2 mm
Molybdenum heat buffer plate, diameter 130mm, thickness 20
The amount of deflection generated in the heat buffer plate / post electrode assembly when the copper post electrode having a thickness of 20 mm and a lattice size of 20 mm was joined at 800 ° C. and then cooled to room temperature was determined. Note that the vertical axis in FIG. 9 is a plot of the ratio based on the amount of deflection generated when no groove is formed in the post electrode (grid groove depth = 0).

FIG. 9 shows that the amount of deflection generated in the thermal buffer plate / post electrode assembly tends to decrease as the lattice depth increases, and that the specific force of lattice depth / post electrode thickness is 0.1%. It can be seen that the thermal stress generated at 2 or more can be reduced to 1/2 or less. In consideration of the parallelism between the front and back surfaces of the heat buffer plate / post electrode assembly during use, it is desirable that the amount of deflection generated is small, and the ratio of the depth of the grid formed on the post electrode / the thickness of the post electrode is 0.6 or more is preferable.

FIG. 10 shows the width of the groove formed in the post electrode,
The relation of the maximum thermal stress generated at the tip of the groove is shown. In FIG. 10, a molybdenum heat buffer plate having a diameter of 130 mm and a thickness of 2 mm, and a copper post electrode having a diameter of 130 mm, a thickness of 20 mm, a grid size of 20 mm and a grid depth of 10 mm are 800
After joining at a temperature of C, the maximum thermal stress generated at the tip of the groove formed in the post electrode when cooled to room temperature was determined.

FIG. 10 shows that the thermal stress generated at the tip of the groove formed in the post electrode tends to decrease as the groove width increases, and the thermal stress generated when the groove width is 0.5 mm or more is reduced. It can be seen that the stress can be reduced to below the yield stress of copper. In consideration of thermal fatigue when a thermal cycle is added, the generated thermal stress is preferably 100 MPa or less,
It can be said that the width of the groove is preferably 1 mm or more.

FIG. 11 shows the relationship between the thickness of the heat buffer plate and the amount of deflection of the heat buffer plate / post electrode assembly. In FIG. 11, a molybdenum heat buffer plate having a diameter of 130 mm and a diameter of 130 mm
mm, thickness 20mm, grid size 20mm, grid depth 1
After joining a 0 mm copper post electrode at 800 ° C. and then cooling to room temperature, the amount of deflection generated in the heat buffer plate / post electrode assembly was determined.

FIG. 11 shows that the amount of deflection generated in the thermal buffer / post electrode assembly decreases as the thickness of the thermal buffer increases. As shown in FIG. 7, molybdenum and tungsten, which are suitable as heat buffer plates, have poor machinability, and when the amount of deflection is large, machining for increasing the parallelism of the heat buffer plate / post-electrode assembly. Teens increase. From the result of FIG. 11, the value of electrode plate thickness / post electrode thickness shows that the deflection amount tends to gradually saturate when the value of electrode plate thickness / post electrode thickness is 0.05 or more. 0.05 or more, preferably 0. It is desirably at least l.

FIG. 12 shows a molybdenum heat buffer plate having a diameter of 50 mm and a thickness of 2 mm above and below a semiconductor element having a diameter of about 50 mm according to the structure of the press contact type semiconductor device of the present invention shown in FIG. The results of the measurement of the contact thermal resistance of a field base in which a copper post electrode having a thickness of 20 mm was joined and the thermal buffer plate / post electrode assembly was pressed from above and below with a pressure of 50 kgf / mm ² were shown. The joint surface of the copper post electrode with the thermal buffer plate had a lattice size of 10 mm and a depth of 1 mm.
A groove having a width of 0 mm and a width of 2 mm was machined, and the measurement was performed while changing the surface roughness of the heat buffer plate in contact with the semiconductor element and the surface roughness of the post electrode in contact with the water-cooled heat sink plate.

As shown in FIG. 5, by integrating the heat buffer plate and the post electrode by bonding, the contact thermal resistance can be reduced to about 1/6 of the conventional one, but as shown in FIG. As the surface roughness of the contact surface is reduced, the contact thermal resistance of the semiconductor device can be further reduced, and the surface roughness of the contact surface is reduced by 0.5 μm.
m, the contact thermal resistance of the semiconductor device is reduced to 1/1.
It can be seen that it can be reduced to 0 or less.

As described above, according to the present invention, it is possible to manufacture a semiconductor device having extremely low contact thermal resistance, and it is possible to greatly reduce the size and cost of the cooling unit. Further, the semiconductor strand can be cooled uniformly, and
The external pressure can be evenly applied to the semiconductor element, and a highly reliable semiconductor device can be manufactured.

[0054]

According to the present invention, the reliability of the pressure contact type semiconductor device can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a press contact type semiconductor device according to the present invention.

FIG. 2 is a plan view of a post electrode provided with lattice grooves used in FIG.

FIG. 3 is a plan view of a post electrode provided with concentric grooves used in FIG.

FIG. 4 is a plan view of another post electrode provided with a lattice-like groove used in FIG. 1;

FIG. 5 is an explanatory view showing a comparison between the present invention, a conventional example, and a contact thermal resistance value.

FIG. 6 is an explanatory diagram showing an influence on a deflection amount of a post electrode / heat buffer plate assembly.

FIG. 7 is an explanatory diagram showing a comparison between a thermal resistance value and an elastic coefficient of a post electrode material.

FIG. 8 is an explanatory diagram showing an influence of a lattice size on a deflection amount of a post electrode.

FIG. 9 is an explanatory diagram showing an influence of a groove depth on a deflection amount of a post electrode.

FIG. 10 is an explanatory diagram showing an influence of a groove width on a thermal stress of a post electrode.

FIG. 11 is an explanatory diagram showing the effect of the thickness of the heat buffer plate on the amount of deflection of the post electrode.

FIG. 12 is an explanatory diagram illustrating the influence of surface roughness on contact thermal resistance of a semiconductor device.

FIG. 13 is a front view showing a first manufacturing step of the press-contact type semiconductor device.

FIG. 14 is a front view showing a second manufacturing step of the pressure contact type semiconductor device.

FIG. 15 is a front view showing a third manufacturing step of the pressure contact type semiconductor device.

FIG. 16 is a front view showing a fourth manufacturing step of the pressure contact type semiconductor device.

FIG. 17 is a cross-sectional view illustrating a structure of a conventional pressure contact type semiconductor device.

[Description of Signs] 12a, 12c: Thermal buffer plates 13a, 13c: Post electrodes 14a, 14c: Groove 15: Semiconductor substrate 16a, 16c: Electrode 18: Cylindrical container 19a, 19c: Metal flange

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Ishiwatari 2-4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Keihin Plant (72) Inventor Atsushi Yamamoto 1st Toshiba-cho, Fuchu-shi, Tokyo Toshiba Corporation Inside the Fuchu Plant (72) Takashi Kusano Inventor Takashi Kusano 1 Toshiba-cho, Fuchu-shi, Tokyo Inside the Fuchu Plant Toshiba Corporation (72) Inventor Atsushi Kimoto 2-4 Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Pref. (72) Inventor Takao Inukai 2--4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside the Keihin Works, Toshiba Corporation (72) Inventor Yoshiyasu Ito 2-1 Ukishimacho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Toshiba Hamakawasaki Plant, Ltd. (72) Inventor Akinori Nagata 2-4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Inside the Toshiba Keihin Plant Term (Reference) 5F036 AA01 BB01 BB14 BC06 BD01 BD03 BE06 5F047 JA01 JA02 JA03 JA04 JA07

Claims (12)

[Claims] 1. A semiconductor device having electrodes provided on both main surfaces of a semiconductor substrate, a heat buffer plate provided on both surfaces of the semiconductor device and connected to the electrodes, and a post connected outside the heat buffer plate. In a press-contact type semiconductor device comprising electrodes, the post electrode is fixedly joined to the thermal buffer plate and a groove is formed on a surface facing the joint surface. 2. The pressure welding according to claim 1, wherein the groove formed in the post electrode and the facing surface does not penetrate to the outer peripheral portion of the post electrode and the joint surface with the thermal buffer plate. Type semiconductor device. 3. The opposing surface of the post electrode includes a grid-like region separated by the groove and a ring-shaped region on the outer periphery, and the outermost grid of the grid-like region and the ring-shaped region. 3. The pressure-contact type semiconductor device according to claim 1, wherein the groove is divided by the groove. 4. The material of the post electrode is copper, aluminum, or an alloy containing these metals as a main component,
4. The pressure-contact type semiconductor device according to claim 1, wherein the material of the thermal buffer plate is tungsten, molybdenum, or an alloy containing these metals as a main component. 5. The pressure-contact type semiconductor device according to claim 1, wherein the groove is in a lattice shape or a concentric shape. 6. The pressure-contact type semiconductor device according to claim 1, wherein one side of the groove has a length of 30 mm or less. 7. The depth of the groove is equal to 0. 0 of the thickness of the post electrode.
4. The method according to claim 1, wherein the number is twice or more.
Press-contact type semiconductor device according to any one of the above. 8. The pressure-contact type semiconductor device according to claim 1, wherein the width of the groove is 0.5 mm or more. 9. The pressure welding type according to claim 1, wherein the thickness of the heat buffer plate is at least 0.05 times the thickness of the post electrode. Semiconductor device. 10. The pressure-contact type semiconductor device according to claim 1, wherein a surface roughness of the opposing surface of the post electrode and a surface of the thermal buffer plate contacting the semiconductor element are 6 μm or less. 11. In the post electrode, a height of an outer peripheral region having no groove is higher than a height of an inner region forming the groove, and a flange for sealing the outer peripheral region without the groove and at least the semiconductor device is formed. 2. The press-contact type semiconductor device according to claim 1, wherein the first and second members are joined by welding. 12. The press-contact type semiconductor device according to claim 1, wherein after the heat buffer plate and the post electrode are fixedly joined, upper and lower surfaces of a joined body of the heat buffer plate and the post electrode are machined. Production method.