JP2868007B1 - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

The present invention provides a semiconductor device and a method for manufacturing the same, which can prevent the progress of corrosion and peeling of a metal heat radiating plate, improve the heat radiation characteristics of a device, and can be manufactured at low cost. I do. SOLUTION: First, a copper plate 1 is clad on both sides of a molybdenum plate 2 and the clad plate is punched by press working, and then an electroless nickel-phosphorus plating layer 4 is formed on the surface of the clad plate to form a heat sink. Is prepared. Then
When a ceramic frame is placed on a heat sink through a silver-copper brazing material and heated, the silver-copper brazing material melts and the heat sink and the ceramic frame are brazed and joined, and the molten brazing material flows out to release heat. A silver-copper alloy film 7 made of a brazing material is formed on the end surface of the plate and the semiconductor element mounting surface, and on the surface and end surface of the heat sink. Thereafter, gold plating is applied to the entire surface to form a gold plating layer on the entire surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a metal radiator plate and a method of manufacturing the same, and more particularly, to a semiconductor device having a metal radiator plate capable of preventing a decrease in heat dissipation of a semiconductor element and a method of manufacturing the same. About.

[0002]

2. Description of the Related Art Hitherto, as a radiator plate on which a semiconductor element is mounted, various types of structures have been proposed for the purpose of improving the heat radiation of the element (JP-A-5-29507, JP-A-5-29507). No. 5-21667). FIG. 6 is a perspective view showing a structure of a conventional semiconductor device, and FIGS. 7 and 8 are sectional views showing a part of the structure in an enlarged manner. As shown in FIG. 6, a semiconductor element 33 is mounted on a semiconductor element mounting surface 29 on the surface of the metal heat sink 23, and a ceramic frame 25 surrounding the semiconductor element 33 is brazed and joined. . The metal heat radiating plate 23 is formed by forming an electrolytic nickel plating layer 24 on the surface of a three-layer clad plate in which the copper plate 21 is clad on both surfaces of a molybdenum plate 22. Further, on the ceramic frame 25, a lead 26 for connecting a wiring inside the semiconductor element 33 and an external wiring is formed.

[0003] Such a conventional semiconductor device is manufactured as follows. As shown in FIG. 7, first, a copper plate 21 is clad on both sides of a molybdenum plate 22, and this is punched into a predetermined shape by press working. Next, an electrolytic nickel plating layer 24 is formed on the surface of the punched clad plate, and a heat sink 23 is manufactured. Next, the ceramic frame 25 is joined onto the heat sink 23 using the silver-copper brazing material 27. Thereafter, after the leads 26 are joined to the upper surface of the ceramic frame 25, the gold plating layer 8 is formed on the entire surface.

[0004] Thereafter, as shown in FIG. 8, a semiconductor element 33 is mounted on a semiconductor element mounting surface 29 surrounded by a ceramic frame 25 via a mounting material 34.
And the lead 26 are connected.

In the semiconductor device configured as described above, since the metal heat radiating plate 23 having the copper plate 21 having high thermal conductivity bonded to both surfaces is used, the heat of the semiconductor element can be efficiently radiated. it can. Further, when the clad plate is processed into a predetermined shape, a method of punching by press working is used, so that the heat radiating plate 23 can be formed at low cost. Further, since the metal heat radiating plate 23 composed of the two copper plates 21 and the molybdenum plate 22 therebetween is used, the stress applied to the ceramic frame 25 is reduced.

[0006]

However, the conventional semiconductor device shown in FIGS. 6 and 7 has the following problems. The first problem is that peeling between the copper plate 21 and the molybdenum plate 22 is likely to occur on the end surface of the heat sink 23. This is because the bonding force at the interface between the clad copper plate 21 and the molybdenum plate 22 is weak, so that a gap 32 is generated between the copper plate 21 and the molybdenum plate 22 by press working. That is, the gap 32 serves as a starting point, and peeling occurs due to thermal stress. As described above, when peeling occurs on the end surface of the heat sink, the peeling progresses due to a heat history and a temperature cycle test at the time of assembling the semiconductor device, and the characteristics of the device deteriorate.

The second problem is that it is difficult to form the gold plating layer 28 in the gap 32 between the copper plate 21 and the molybdenum plate 22 generated by press working on the end surface of the heat radiating plate 23. Since the gold-plated layer 28 has a function of preventing corrosion of the heat radiating plate 23, if there is an unattached portion of the gold-plated layer 28 on the heat radiating plate 23, corrosion occurs from this unattached portion.

A third problem is that, as shown in FIG. 8, irregularities are formed on the surfaces of the electrolytic nickel plating layer 24 and the gold plating layer 28 on the surface of the metal radiator plate 23, and When mounting the semiconductor element 33, a void 37 is formed between the unevenness on the surface of the gold plating layer 28 and the mount material 34. If the voids 37 remain even after the semiconductor element 33 is mounted, the voids 37 become thermal resistance when releasing the heat of the semiconductor element 33, and the heat radiation characteristics of the metal heat radiating plate 23 deteriorate.

[0009] Among these problems, a heat radiating plate capable of preventing the occurrence of corrosion due to peeling of the end surface of the heat radiating plate and the non-adhesion of the plating layer has been disclosed (Japanese Patent Laid-Open No. 63-016582). . This radiator plate is obtained by forming an electroless nickel plating layer on a copper-tungsten sintered alloy plate. Since the copper-tungsten sintered alloy plate is a brittle material having high hardness, it is processed into a predetermined shape by cutting instead of pressing. Therefore, since the end surface of the heat sink is flat, there is no occurrence of peeling and corrosion due to the non-adhesion of the plating layer.

However, Japanese Patent Application Laid-Open No. 63-016582 discloses
In the radiator plate disclosed in Japanese Patent Application Laid-Open No. H10-260, there is a problem that the processing cost is significantly increased because the processing is performed by cutting. There is also a problem that the heat radiation characteristics of the heat radiation plate are lower than those of the semiconductor device shown in FIGS.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and can prevent corrosion and peeling of a metal heat radiating plate from proceeding, improve the heat radiating characteristics of a device, and reduce the cost. An object of the present invention is to provide a semiconductor device that can be manufactured and a manufacturing method thereof.

[0012]

A semiconductor device according to the present invention comprises a heat sink, a semiconductor element mounted on the heat sink, and a frame member brazed on the heat sink and surrounding the semiconductor element. Wherein the heat sink has a clad plate having a three-layer structure in which a copper plate is clad on both sides of a molybdenum plate, and an electroless nickel-phosphorus plating layer formed on the surface of the clad plate. It is characterized by.

It is preferable that the semiconductor device further includes a metal film made of the brazing material formed on a region where the semiconductor element is to be mounted on the heat sink and on an end face of the heat sink. Further, it may have a gold plating layer formed on the surface of the metal film. Further, it is preferable to have an electrolytic nickel plating layer formed on the surface of the metal film and a gold plating layer formed on the surface of the electrolytic nickel plating layer. Further, it is desirable to have a silver plating layer formed on the surface of the metal film.

Further, the frame material may be brazed on the heat sink with a silver-copper brazing material, and in this case, the metal film may be a silver-copper alloy film. Furthermore, the frame material may be made of ceramic.

In the method of manufacturing a semiconductor device according to the present invention, a step of manufacturing a heat sink on which a semiconductor element is mounted, and a step of forming a frame material surrounding a region where the semiconductor element is to be mounted on the heat sink on the heat sink. And a step of mounting a semiconductor element on the area where the semiconductor element is to be mounted. In the method of manufacturing a semiconductor device, the step of manufacturing the heat sink includes cladding a copper plate on both sides of a molybdenum plate. A step of manufacturing a clad plate having a layer structure, a step of punching the clad plate into a predetermined shape by press working, and a step of performing electroless nickel phosphorus plating on the surface of the clad plate having the predetermined shape. It is characterized by.

The step of brazing the frame material on the radiator plate includes the steps of disposing a braze material between the radiator plate and the frame material, and heating and melting the braze material to form the frame material. And brazing the radiator plate and applying a metal film made of a molten brazing material to an area where the semiconductor element is to be mounted on the radiator plate and an end surface of the radiator plate. preferable.

Further, between the step of attaching a metal film on the semiconductor element mounting area on the heat sink and the end face of the heat sink, and the step of mounting the semiconductor element on the semiconductor element mounting area, The method may include a step of plating the surface of the metal film with gold. Further, between the step of attaching a metal film to the semiconductor element mounting area on the heat sink and the end face of the heat sink, and the step of mounting a semiconductor element on the semiconductor element mounting area, It is preferable to include a step of applying electrolytic nickel plating to the surface of the substrate and a step of applying gold plating to the surface of the electrolytic nickel plating layer formed by the electrolytic nickel plating. Furthermore, between the step of attaching a metal film to the semiconductor element mounting area on the heat sink and the end face of the heat sink, and the step of mounting a semiconductor element on the semiconductor element mounting area, It is desirable to have a step of applying silver plating to the surface of the film.

Still further, the brazing material may be a silver-copper brazing material, and in this case, the metal film may be a silver-copper alloy film. Furthermore, the frame material can be formed of ceramic.

In the present invention, the surface of a three-layer clad plate in which a copper plate is clad on both sides of a molybdenum plate,
A heat sink having an electroless nickel phosphorus plating layer formed thereon is used. Since the surface of the electroless nickel-phosphorous plating layer is in a state where the molten brazing material is easy to flow, the cladding plate is subjected to electroless nickel-phosphorous plating to form a heat radiating plate, and then the heat radiating plate and frame material are formed by the brazing material. And joining
The molten brazing material flows on the surface of the electroless nickel-phosphorous plating layer and reaches the end surface of the heat sink. Then, the brazing material enters the gap between the copper plate and the molybdenum plate, and the gap is completely buried by the metal film made of the brazing material. As a result, a strong metal bond is obtained between the copper plate and the molybdenum plate at the end surface of the heat radiating plate, and the progress of peeling between the copper plate and the molybdenum plate can be prevented.

In the present invention, when the gap is completely buried by the metal film, the end face of the heat sink becomes a substantially flat surface. Therefore, when the heat sink is plated with gold, the gold plated layer is formed on the entire surface without forming the unattached portion of the gold plated layer on the end surface of the heat sink, so that corrosion of the heat sink can be prevented. .

Further, in the present invention, when the molten brazing material flows out of the surface of the electroless nickel-phosphorous plating layer on the surface of the heat sink and reaches the semiconductor element mounting area surrounded by the frame material, this area becomes The flatness of the surface of the heat sink is improved by being covered with the metal film made of the brazing material. Therefore, when the semiconductor element is mounted in the element mounting area in a subsequent step, it is possible to suppress the occurrence of voids inside the mounting material or the like for mounting, thereby improving the heat radiation characteristics of the device. Can be done.

In the present invention, when an electrolytic nickel plating layer is formed on the surface of the metal film and then a gold plating layer is formed, the electrolytic nickel plating layer is formed by heat diffusion of the metal film on the surface of the gold plating layer. Has the effect of preventing the gold plating layer from being exposed to the substrate, so that the thickness of the gold plating layer can be reduced, and the semiconductor device can be manufactured at low cost. In the present invention, when a silver plating layer is formed on the surface of a metal film, a semiconductor device can be manufactured at a much lower cost than when a gold plating layer is formed.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a semiconductor device according to an embodiment of the present invention and a method of manufacturing the same will be specifically described with reference to the accompanying drawings. FIG. 1 is a perspective view showing the structure of a semiconductor device according to a first embodiment of the present invention, and FIGS. 2A to 2C and 3 are cross-sectional views showing the manufacturing method in the order of steps. As shown in FIG. 1, a semiconductor element 13 is mounted on a metal radiator plate 3, and the semiconductor element 1
A ceramic frame (frame material) 5 having a shape surrounding 3 is brazed and joined. The metal radiator plate 3 is a molybdenum plate 2
An electroless nickel-phosphorous plating layer 4 is formed on the surface of a three-layered clad plate having a copper plate 1 clad on both sides. Further, on the ceramic frame 5, a lead 6 for connecting a wiring inside the semiconductor element 13 and an external wiring is formed.

The semiconductor device according to the present embodiment thus constructed is manufactured as described below. FIG.
As shown in (a), first, a copper plate 1 is clad on both sides of a molybdenum plate 2, and the clad plate is punched into a predetermined shape by press working. At this time, the sagging surface 10 and the burr surface 11 are formed on the end surface of the clad plate by press working. Also, a copper plate 1 and a molybdenum plate 2
Are different in hardness from each other, the stress at the time of press working causes the copper plate 1 and the molybdenum plate 2 to be separated from each other to form the gap 12.

Next, as shown in FIG. 2B, an electroless nickel-phosphorus plating layer 4 is formed on the surface of the punched clad plate, and a heat sink 3 is manufactured. At this time, since the plating solution for forming the electroless nickel-phosphorous plating layer 4 does not circulate in the gap 12, the surfaces of the copper plate 1 and the molybdenum plate 2 near the gap 12 are coated with the nickel-phosphorous plating layer 4. Is not formed.

Next, the ceramic frame 5 is joined onto the heat sink 3. At this time, an alloy preform having the same shape as the joint surface between the ceramic frame 5 and the heat sink 3, for example, a silver-copper brazing material (not shown) is disposed between the two, and the brazing material is made to about 850, for example. Heat to a temperature of ° C. As a result, FIG.
As shown in (c), the silver-copper brazing material is melted at the joint surface between the ceramic frame 5 and the metal heat radiating plate 3, and the heat radiating plate 3 and the ceramic frame 5 are brazed and joined, and the molten solder is melted. The material flows out to reach the end face of the heat sink 3 and the semiconductor element mounting surface (semiconductor element formation planned area) 9 surrounded by the ceramic frame 5, and forms a silver-copper alloy film (metal) on the surface and end face of the heat sink 3. A film 7 is formed.

Thereafter, the leads 6 are placed on the upper surface of the ceramic frame 5.
After bonding, a gold plating layer 8 is formed on the entire surface of the silver-copper alloy film by performing gold plating on the entire surface. Thereafter, as shown in FIG.
The semiconductor element 13 is mounted thereon via a mounting material 14 made of AuSn or the like, and the wiring in the semiconductor element 13 and the lead 6 are connected.

In the semiconductor device manufactured in this manner, a heat sink having an electroless nickel-phosphorous plating layer 4 formed on the surface of a three-layer clad plate in which a copper plate 1 is clad on both surfaces of a molybdenum plate 2. 3 is used. Since the surface of the electroless nickel-phosphorous plating layer 4 is in a state in which the molten silver-copper brazing material easily flows, the heat-dissipating plate 3 is formed by performing electroless nickel-phosphorous plating on the clad plate, When the heat radiating plate 3 and the ceramic frame 5 are joined by a material, the molten silver-copper brazing material flows on the surface of the electroless nickel-phosphorous plating layer 4 and reaches the end surface of the heat radiating plate 3. Further, the molten silver-copper brazing material penetrates into the gap 12 between the copper plate 1 and the molybdenum plate 2 due to the capillary phenomenon and solidifies, so that the gap 12 is completely embedded by the silver-copper alloy film 7. You. Thereby, a strong metal bond is obtained between the copper plate 1 and the molybdenum plate 2 at the end surface of the heat radiating plate 3, and the separation between the copper plate 1 and the molybdenum plate 2 does not progress.

In this embodiment, since the gap 12 is completely buried with the silver-copper alloy film 7, the end face of the heat sink 3 is substantially flat. Therefore, when the heat sink 3 is plated with gold, the circulation of the plating solution becomes good, and the gold plated layer 8 is formed on the entire surface without forming the unattached portion of the gold plated layer 8 on the end face of the heat sink 3. So
Corrosion of the heat sink 3 can be prevented.

Further, in this embodiment, the molten silver-copper brazing material flows out of the surface of the electroless nickel-phosphorous plating layer 4 on the surface of the radiator plate 3 and is transferred to the semiconductor element mounting surface 9 surrounded by the ceramic frame 5. As a result, the semiconductor element mounting surface 9 is covered with the silver-copper alloy film 7. As shown in FIG. 3, immediately after forming the electroless nickel phosphorus plating layer 4,
Irregularities are formed on the surface of the metal heat sink 3. However, since the surface of the heat radiating plate 3 is covered with the silver-copper alloy film 7, the flatness of the surface of the heat radiating plate 3 is improved. Therefore, when the semiconductor element 13 is mounted on the element mounting surface 9 by the mounting material 14 in a subsequent step, the inclination and the like of the semiconductor element 13 are reduced, so that a void is formed in the mounting material 14 as compared with the conventional semiconductor device. Can be reduced, thereby improving the heat radiation characteristics of the device.

Further, in this embodiment, since the metal heat radiating plate 3 having the copper plate 1 having high thermal conductivity bonded to both surfaces is used, the heat of the semiconductor element can be efficiently radiated. Further, since the clad plate is processed into a predetermined shape by punching by press working, the heat radiating plate 3 can be manufactured at low cost. Furthermore, two copper plates 1
Since the metal heat radiating plate 3 made of the molybdenum plate 2 is used between them, the stress applied to the ceramic frame 5 can be reduced.

FIG. 4 is an enlarged sectional view showing a part of a semiconductor device according to a second embodiment of the present invention. In the second embodiment shown in FIG. 4, the same components as those in the first embodiment shown in FIGS. 2 and 3 are denoted by the same reference numerals, and detailed description thereof will be omitted. Further, the semiconductor device to be manufactured is the same as the structure of the semiconductor device shown in FIG. 1, and therefore, the structure of the semiconductor device according to the second embodiment is not shown. As shown in FIG. 4, in the second embodiment, the first step is until the step of brazing and joining the ceramic frame on the heat sink at a temperature of 850 ° C.
This is the same as the embodiment. Thus, the surface of the metal radiator plate is covered with the silver-copper alloy film 7.

Next, after joining leads (not shown) to the upper surface of the ceramic frame (not shown), an electrolytic nickel plating layer 15 is formed on the entire surface. Next, the gold plating layer 8 is formed on the surface of the electrolytic nickel plating layer 15. Thereafter, a semiconductor element (not shown) is mounted on the semiconductor element mounting surface of the heat sink via a mount material, and the wiring in the semiconductor element is connected to the leads.

Also in the second embodiment manufactured in this manner, an electroless nickel-phosphorus plating layer 4 is formed on the surface of a three-layer clad plate in which a copper plate 1 is clad on both surfaces of a molybdenum plate 2. Since a heat sink is used,
The same effect as in the first embodiment can be obtained. Furthermore,
In the second embodiment, an electrolytic nickel plating layer 15 is formed after a ceramic frame is brazed on a heat radiating plate with a silver copper brazing material and before gold plating is performed. In the process of assembling and mounting the semiconductor device after the formation of the gold plating layer 8, the electrolytic nickel plating layer 15 is affected by the heat of the silver-copper alloy film 7 covering the surface of the heat sink, and the gold plating is performed by thermal diffusion. This has the effect of preventing exposure to the surface of the layer 8. Accordingly, the thickness of the gold plating layer 8 can be reduced, so that the amount of gold, which is a noble metal, can be reduced. As a result, the semiconductor device can be manufactured at lower cost as compared with the first embodiment. Can be manufactured.

FIG. 5 is an enlarged sectional view showing a part of a semiconductor device according to a third embodiment of the present invention. In the third embodiment shown in FIG. 5, the same components as those in the first embodiment shown in FIGS. 2 and 3 are denoted by the same reference numerals, and detailed description thereof will be omitted. Further, the semiconductor device to be manufactured is the same as the structure of the semiconductor device shown in FIG. 1, and thus the structure of the semiconductor device according to the third embodiment is not shown. As shown in FIG. 5, in the third embodiment, the first step is until the step of brazing and joining the ceramic frame on the heat sink at a temperature of 850 ° C.
This is the same as the embodiment. Thus, the surface of the metal radiator plate is covered with the silver-copper alloy film 7.

Next, after joining a lead (not shown) to the upper surface of the ceramic frame (not shown), a silver plating layer 1 is formed on the entire surface.
6 is formed. Then, a semiconductor element (not shown) is mounted on the semiconductor element mounting surface of the heat sink via a mounting material,
The wiring in the semiconductor element is connected to the lead.

Also in the third embodiment manufactured in this manner, an electroless nickel-phosphorus plating layer 4 is formed on the surface of a three-layer clad plate in which a copper plate 1 is clad on both surfaces of a molybdenum plate 2. Since a heat sink is used,
The same effects as in the first and second embodiments can be obtained. Furthermore, in the third embodiment, after the ceramic frame is brazed on the heat sink with a silver-copper brazing material, the gold plating layer 8 is formed.
Is formed, the silver plating layer 16 is formed.
Therefore, a semiconductor device can be manufactured at a much lower cost than in the first and second embodiments in which the gold plating layer 8 is formed.

[0038]

As described in detail above, according to the present invention,
Since a heat sink with an electroless nickel-phosphorous plating layer is used on the surface of a three-layer clad plate in which a copper plate is clad on both sides of a molybdenum plate, the gap between the copper plate and the molybdenum plate is used. A metal film made of a brazing material can be formed, thereby preventing the progress of peeling between the copper plate and the molybdenum plate, and forming a gold plating layer on the entire end surface of the heat sink. Therefore, corrosion of the heat sink can be prevented. Further, in the present invention, when the area where the semiconductor element is to be mounted is covered with a metal film made of a brazing material, the flatness of the surface of the heat sink is improved, so that voids are generated inside the mounting material. Can be reduced, thereby improving the heat radiation characteristics of the device.

Further, in the method of the present invention, when manufacturing the heat sink, the clad plate is processed into a predetermined shape by punching by press working, so that a semiconductor device can be manufactured at low cost. Furthermore, in the present invention, when an electrolytic nickel plating layer is formed on the surface of the metal film and then a gold plating layer is formed, the electrolytic nickel plating layer prevents the metal film from being exposed to the surface of the gold plating layer. Accordingly, the thickness of the gold plating layer can be reduced, and a semiconductor device can be manufactured at low cost. Furthermore, in the present invention, when a silver plating layer is formed on the surface of a metal film, a semiconductor device can be manufactured at a much lower cost than when a gold plating layer is formed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a structure of a semiconductor device according to a first embodiment of the present invention.

FIGS. 2A to 2C are cross-sectional views illustrating a method of manufacturing a semiconductor device according to a first embodiment of the present invention in the order of steps.

FIG. 3 is a sectional view showing a step subsequent to FIG. 2 (c).

FIG. 4 is an enlarged sectional view showing a part of a semiconductor device according to a second embodiment of the present invention;

FIG. 5 is an enlarged sectional view showing a part of a semiconductor device according to a third embodiment of the present invention;

FIG. 6 is a perspective view showing the structure of a conventional semiconductor device.

FIG. 7 is an enlarged cross-sectional view showing a part of a conventional semiconductor device.

FIG. 8 is a cross-sectional view showing an enlarged part of a conventional semiconductor device.

[Explanation of symbols]

 1, 21; copper plate 2, 22; molybdenum plate 3, 23; heat sink 4, electroless nickel phosphorus plating layer 5, 25; ceramic frame 6, 26; lead 7, silver-copper alloy film 8, 28; 29; semiconductor element mounting surface 10; sagging surface 11; burr surface 12, 32; gap portion 13, 33; semiconductor element 14, 34; mounting material 15, 24; electrolytic nickel plating layer 16; silver plating layer 27; Material 37; void

Claims (14)

(57) [Claims] 1. A semiconductor device comprising: a heat sink; a semiconductor element mounted on the heat sink; and a frame material brazed on the heat sink and surrounding the semiconductor element. A semiconductor device comprising: a clad plate having a three-layer structure in which a copper plate is clad on both surfaces of a molybdenum plate; and an electroless nickel-phosphorous plating layer formed on a surface of the clad plate. 2. The semiconductor device according to claim 1, further comprising a metal film formed on the heat radiation plate on a region where the semiconductor element is to be mounted and on an end surface of the heat radiation plate, the metal film being made of the brazing material. . 3. The semiconductor device according to claim 2, further comprising a gold plating layer formed on a surface of said metal film. 4. The method according to claim 2, comprising: an electrolytic nickel plating layer formed on the surface of the metal film; and a gold plating layer formed on the surface of the electrolytic nickel plating layer. Semiconductor device. 5. The semiconductor device according to claim 2, further comprising a silver plating layer formed on a surface of said metal film. 6. The frame material according to claim 2, wherein the frame material is brazed on the heat radiating plate with a silver-copper brazing material, and the metal film is a silver-copper alloy film. 2. The semiconductor device according to claim 1. 7. The semiconductor device according to claim 1, wherein said frame member is made of ceramic. 8. A step of manufacturing a heat sink on which the semiconductor element is mounted, and a step of brazing a frame material having a shape surrounding a region where the semiconductor element is to be mounted on the heat sink, onto the heat sink.
A step of mounting a semiconductor element on the semiconductor element mounting area, wherein the step of manufacturing the heat sink includes cladding a copper plate on both sides of a molybdenum plate to form a three-layer clad plate. A step of producing
A method for manufacturing a semiconductor device, comprising: a step of processing the clad plate into a predetermined shape by punching by press working; and a step of performing electroless nickel phosphorus plating on a surface of the clad plate having the predetermined shape. 9. A step of brazing the frame material on the heat sink, a step of disposing a brazing material between the heat sink and the frame material, and heating and melting the brazing material. Brazing the frame material and the heat sink, and applying a metal film made of a molten brazing material to an area where the semiconductor element is to be mounted on the heat sink and an end surface of the heat sink. The method for manufacturing a semiconductor device according to claim 8, wherein: 10. A step of attaching a metal film to the semiconductor element mounting area on the heat sink and an end surface of the heat sink, and mounting a semiconductor element on the semiconductor element mounting area. The method according to claim 9, further comprising a step of performing gold plating on a surface of the metal film. 11. A step of attaching a metal film to the semiconductor element mounting area on the heat sink and an end surface of the heat sink, and mounting a semiconductor element on the semiconductor element mounting area. 10. The semiconductor device according to claim 9, comprising: a step of applying electrolytic nickel plating to a surface of the metal film; and a step of applying gold plating to a surface of an electrolytic nickel plating layer formed by the electrolytic nickel plating. Manufacturing method. 12. A step of depositing a metal film on the semiconductor element mounting area on the heat sink and an end face of the heat sink, and mounting a semiconductor element on the semiconductor element mounting area. The method according to claim 9, further comprising a step of performing silver plating on a surface of the metal film. 13. The semiconductor device according to claim 9, wherein the brazing material is a silver-copper brazing material, and the metal film is a silver-copper alloy film. 14. The method for manufacturing a semiconductor device according to claim 8, wherein said frame member is formed of ceramic.