JPH09107057A - Semiconductor element mounting plastic package and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor element mounting plastic package having a heat radiation board in which reliability of junction between the plastic package and the radiation board or between a semiconductor element and the radiation board may be achieved even at the time of mounting a large-scale semiconductor element and which does not require any complex manufacturing processes. SOLUTION: This package includes a radiation board 3, and a plastic package body 1 which surrounds a semiconductor element 9 joined with the radiation board 3 via a junction layer 8 and which is joined with the radiation board 3 via a junction layer 7. The radiation board 3 contains at least one alloy selected from the group of copper-tungsten alloy containing 25-40% by weight of copper, copper-molybdenum alloy containing 25-40% by weight of copper, and copper-molybdenum-tungsten alloy containing 25-40% by weight of copper. The surface of the radiation board 3 which is joined with the semiconductor element 9 and the plastic package body 1 has a centerline average plane roughness (Ra) within a range of 0.2-1.5μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic package on which a semiconductor element is mounted, and more particularly to a plastic package with a heat dissipation board for dissipating heat generated during operation of a large semiconductor element to the outside of the package system and a method for manufacturing the same.

[0002]

2. Description of the Related Art A conventional semiconductor element mounting substrate on which a semiconductor element is mounted is made of plastic or ceramics. Of these materials, plastic is widely used because it is easy to process and relatively inexpensive. However, since the plastic material has poorer thermal conductivity than the ceramic material, it is not sufficient as a substrate for mounting a semiconductor element that generates a large amount of heat. Therefore, in order to improve the above-mentioned drawbacks, a plastic package for mounting a semiconductor element, which has a structure in which a metal plate is bonded to a portion on which a semiconductor element is directly mounted, is referred to as “VLSI packaging technology (bottom)”,
Page 209, published by Nikkei BP, Inc. and Japanese Examined Patent Publication No. 7-46710, and has been used conventionally.

FIG. 5 is a cross-sectional view of a conventional semiconductor element mounting plastic package using a heat dissipation board made of copper or copper alloy for the semiconductor element mounting portion.

Referring to FIG. 5, a plastic package body 101 is a multi-layer plastic substrate composed of BT (bismaleimide-triazine) resin and copper wiring. A heat dissipation board 103 is provided on the plastic package body 101 with a silicone adhesive 107 interposed. The heat dissipation substrate 103 is made of a metal whose main component is copper or a copper alloy. The heat radiation fins 102 are provided on the heat radiation substrate 103 with the silicone adhesive 107 interposed. The heat radiation fin 102 is made of a metal whose main component is aluminum. A semiconductor element 109 is provided below the heat dissipation substrate 103 with an epoxy adhesive 108 interposed. The semiconductor element 109 is an epoxy adhesive 1
It is fixed by 08. The semiconductor element 109 is electrically connected to the metal pin 104 from the bonding wire 105 through the copper wiring of the plastic package body 101. In order to hermetically seal the semiconductor element 109 from the outside air, a metal lid 106 is provided so as to be in contact with the plastic package body 101.

In the semiconductor element mounting plastic package having the above structure, the heat generated during the operation of the semiconductor element 109 passes through the epoxy adhesive 108, the heat dissipation substrate 103 and the silicone adhesive 107. Then, it is transmitted to the radiation fin 102. Radiating fin 102
The heat transmitted to the radiator is dissipated from the radiation fin 102 into the atmosphere. In this way, the heat generated from the semiconductor element 109 is removed.

In recent years, in a plastic package for mounting a semiconductor element, three points, namely, high-density wiring technology, reliability, and signal response speed have been improved. Further, the plastic package for mounting the semiconductor element is easier to process and relatively inexpensive than the ceramic package for mounting the semiconductor element. Therefore, as in the conventional ceramic package, mounting a large-scale semiconductor element with high integration, high density, and high speed in a plastic package is being considered.

With the increase in size of semiconductor elements,
A problem has occurred in the conventional plastic package for mounting semiconductor elements shown in FIG.

Large-sized semiconductor element, especially 7 mm × planar area
When a semiconductor element larger than 7 mm is mounted, a large amount of heat is generated from the large semiconductor element. Here, the thermal expansion coefficient of the heat dissipation board 103 (eg, copper) is 17 × 10 ⁻⁶ / ° C.
On the other hand, since the thermal expansion coefficient of the semiconductor element 109 (for example, silicon) is 4.2 × 10 ⁻⁶ / ° C., the thermal expansion difference between the heat dissipation substrate 103 and the semiconductor element 109 is large.
As a result, stress due to the difference in thermal expansion is applied to the interface between the semiconductor element 109 and the heat dissipation substrate 103, and the reliability of bonding these surfaces is reduced. More specifically, when the semiconductor element 109 is bonded and mounted on the heat dissipation board 103 with an epoxy adhesive containing a silver filler interposed, heat generated during the operation of the semiconductor element 109 is repeatedly applied to the heat dissipation board 103. As a result, repeated stress is applied to the interface between the semiconductor element 109 and the heat dissipation substrate 103. Due to the stress, the semiconductor element 1
09 is peeled off at the interface between the silicone adhesive 108 and the heat dissipation substrate 103 at the interface. Then, from the semiconductor element 109 to the heat dissipation substrate 103.
However, there is a problem in that the heat cannot be easily transmitted to the outside of the package system and the semiconductor element 109 does not operate normally.

[0009]

In order to solve the above problems, a semiconductor element mounting plastic package in which the above-mentioned heat dissipation board containing copper or a copper alloy as a main component is replaced with another alloy is disclosed in Japanese Patent Laid-Open No. Hei 5 (1999) -5. -212148.

FIG. 6 is a sectional view of the semiconductor element mounting plastic package disclosed in the above publication.

Referring to FIG. 6, the plastic package body 201 is a multi-layer plastic substrate composed of BT (bismaleimide-triazine) resin and copper wiring. A heat dissipation substrate 203 is provided on the plastic package body 201 with a silicone adhesive 207 interposed. The heat dissipation substrate 203 is copper-tungsten,
It is made of a composite metal containing copper-molybdenum or copper-tungsten-molybdenum as a main component. Heat dissipation board 2
A semiconductor element 209 is provided below the switch 03 with an epoxy adhesive 208 interposed. The semiconductor element 209 is fixed by an epoxy adhesive 208. The semiconductor element 209 is electrically connected to the metal pin 204 from the bonding wire 205 through the copper wiring of the plastic package body 201. In order to hermetically seal the semiconductor element 209 from the outside air, a metal lid 206 is provided so as to be in contact with the plastic package body 201.

The difference in configuration between this semiconductor element mounting plastic package and the semiconductor element mounting plastic package shown in FIG. 5 is that in FIG.
Is composed of the first heat dissipation board 203a and the second heat dissipation board 203b. The first heat dissipation board 203a is joined to the plastic package body 201. The second heat dissipation board 203b is joined to the semiconductor element 209.
The first heat dissipation substrate 203a is made of copper or a copper alloy containing 95% by weight or more of copper, or 40 to 7 made of copper by the infiltration method.
The main component is a copper-tungsten alloy or a copper-molybdenum alloy containing 0% by weight. In addition, the second heat dissipation substrate 203b
Is a copper containing 5 to 25% by weight of copper, produced by the infiltration method.
The main component is tungsten or copper-molybdenum alloy.

In the semiconductor element mounting plastic package having the heat dissipation board thus constructed, the second heat dissipation board 203b has a coefficient of thermal expansion of 7.0 × 10 ⁻⁶ / ° C.
On the other hand, since the semiconductor element 209 (for example, silicon) has a thermal expansion coefficient of 4.2 × 10 ⁻⁶ / ° C., the difference in thermal expansion between the second heat dissipation substrate 203b and the semiconductor element 209 is small. Therefore, the problem of thermal expansion difference is solved.

Next, the heat dissipation board 20 disclosed in the above publication.
The manufacturing method of No. 3 will be described. 7 and 8 are perspective views showing the manufacturing process of the heat dissipation board 203.

Referring to FIG. 7, the hollow frame 210, which is the first heat dissipation substrate 203a used at the joint with the plastic package body, is a copper-molybdenum powder sintered body, and contains 40% by weight of copper when infiltrated with copper. It is a porous body sintered so as to contain. For example, the second used in the semiconductor element mounting portion.
The flat plate 211 serving as the heat dissipation substrate 203b is a tungsten powder sintered body, which is a porous body sintered to contain, for example, 15% by weight of copper during copper infiltration. This flat plate 21
1 is fitted into the hollow frame 210, copper plates of sufficient weight to fill both porous bodies are stacked, and 120 is placed in a hydrogen atmosphere.
Heat to 0 ° C. to melt the copper and infiltrate the pores of the porous body.
Next, both surfaces are polished, the outer periphery is processed into a predetermined shape, and nickel and gold plating are applied. 25m outside dimension by the above process
m × 25 mm × 3.0 mm, the outer peripheral portion is a first heat dissipation board 203a of copper: molybdenum = 40: 60 (weight ratio), and the inside is a second heat dissipation board 203b of copper: tungsten = 15: 85 (weight ratio). It is possible to obtain the heat dissipation substrate 203 made of.

As described above, in the manufacturing process of the heat dissipation substrate 203, the joining and unifying process shown in FIGS. 7 and 8 is necessary, and there is a problem that the manufacturing cost is inevitably increased due to the complicated process. It was

Therefore, according to the present invention, the heat generated during the operation of the semiconductor element can be efficiently dissipated to the outside of the package system, and further, even when the large semiconductor element is mounted, the large semiconductor element and the plastic package body and the heat dissipation board can be joined together. An object of the present invention is to provide a plastic package for mounting a semiconductor element with a heat dissipation substrate, which achieves reliability and does not require a complicated manufacturing process.

[0018]

A plastic package for mounting a semiconductor element of the present invention surrounds a heat dissipation board and a semiconductor element bonded to the heat dissipation board with a bonding layer interposed therebetween.
And a plastic package body bonded to the heat dissipation board with a bonding layer interposed, and the heat dissipation board is made of copper 25-4.
At least one alloy selected from the group consisting of a copper-tungsten alloy containing 0% by weight, a copper-molybdenum alloy containing 25 to 40% by weight of copper, and a copper-molybdenum-tungsten alloy containing 25 to 40% by weight of copper. The surface of the heat dissipation substrate bonded to the semiconductor element and the plastic package body has a center line average surface roughness (Ra) within the range of 0.2 to 1.5 μm.

In the semiconductor element mounting plastic package having the above structure, the heat generated during the operation of the semiconductor element is transferred to the heat dissipation board through the bonding layer,
It is dissipated outside the package system from the heat dissipation board. Further, the thermal expansion coefficient of the heat dissipation board is 8.7 × 10 ^{−6 to} 11.1 × 10 ^−6.
/ ° C., and the thermal expansion coefficient of the semiconductor element (eg, silicon) is 4.2 × 10 ⁻⁶ / ° C. Therefore, since the difference in thermal expansion coefficient between the heat dissipation board and the semiconductor element and the difference in thermal expansion coefficient between the heat dissipation board and the plastic package body are small,
The stress due to the difference in thermal expansion can be relieved at both the joint between the semiconductor element and the heat dissipation board and the joint between the plastic package body and the heat dissipation board. Further, by controlling the center average surface roughness (Ra) of the heat dissipation substrate to be in the state of Ra = 0.2 to 1.5 μm, the bondability can be improved by the anchor effect at both joints.

In the plastic package for mounting a semiconductor element having the above structure, the plane area is 7 mm × 7.
A semiconductor element larger than mm can be mounted.

A groove may be formed on the surface around the portion of the heat dissipation substrate to which the semiconductor element is joined.

The surface of the heat dissipation board to which the semiconductor element is joined may project from the surface of the heat dissipation board to which the plastic package body is joined.

In the plastic package for mounting a semiconductor element having the above-mentioned structure, when the heat dissipation board and the plastic package body are bonded by the bonding material,
It is possible to prevent the bonding material from flowing out and adhering to the semiconductor element mounting portion.

Further, in the method for manufacturing a plastic package for mounting a semiconductor device of the present invention, a copper-tungsten alloy containing 25 to 40% by weight of copper, a copper-molybdenum alloy containing 25 to 40% by weight of copper, and copper are used as a heat dissipation substrate. 2
Using at least one alloy selected from the group consisting of a copper-molybdenum-tungsten alloy containing 5 to 40% by weight, the surface of the heat dissipation substrate bonded to the semiconductor element and the plastic package body has a center average surface roughness ( Ra) is 0.
After the state of 2 to 1.5 μm, the heat dissipation substrate is bonded to the plastic package body with a bonding material interposed.

The step of bringing the surface of the heat dissipating substrate into a state where the center average surface roughness (Ra) is 0.2 to 1.5 μm may be performed by either grinding or blasting.

In such a method of manufacturing a plastic package for mounting a semiconductor element, the thermal expansion difference between the heat dissipation board and the semiconductor element and the thermal expansion difference between the heat dissipation board and the plastic package body can be reduced. As a result, it is possible to manufacture a semiconductor element mounting plastic package that alleviates the stress due to the difference in thermal expansion at both the joint between the heat dissipation board and the semiconductor element and the joint between the plastic package and the heat dissipation board. Further, the center line average surface roughness (Ra) is Ra = 0.2 by the grinding method or the blasting method.
By controlling to a state of up to 1.5 μm, the semiconductor element bonded more firmly by the anchor effect at both the joint between the semiconductor element and the heat dissipation board and the joint between the plastic package body and the heat dissipation board. A plastic package for mounting can be manufactured. In addition, a plastic package for mounting a semiconductor element can be manufactured without requiring a complicated process of joining and unifying.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows one embodiment of the present invention and is a cross-sectional view showing a semiconductor element mounting plastic package to which a flat plate type heat dissipation substrate is joined. FIG.
Referring to, the plastic package body 1 has a shape surrounding the semiconductor element 9. The plastic package body 1 is a multi-layer plastic substrate made of glass / cloth impregnated with resin such as epoxy as an insulator and copper wiring as a conductor. In order to mount a large-sized semiconductor element, a portion surrounding the semiconductor element 9 is formed to have an inner size such that its plane area is larger than 7 mm × 7 mm. The heat dissipation board 3 is provided on the plastic package body 1 with the bonding layer 7 interposed. The material of the bonding layer 7 may be resin or solder. The heat dissipation substrate 3 is a copper-tungsten alloy containing 25 to 40% by weight of copper,
It consists of either a copper-molybdenum alloy containing 25 to 40% by weight of copper or a copper-molybdenum-tungsten alloy containing 25 to 40% by weight of copper. Further, the center line average surface roughness (Ra) of the surface of the heat dissipation substrate 3 that is bonded to the semiconductor element 9 and the plastic package body 1 is Ra = 0.2 to 1.5 μm.
m. The semiconductor element 9 is arranged below the heat dissipation substrate 3 with the bonding layer 8 interposed. The semiconductor element 9 is fixed by the bonding layer 8. The metal pin 4 is electrically connected to the semiconductor element 9 from the bonding wire 5 through the copper wiring of the plastic package body 1, and signals are input to and output from the semiconductor element 9 through the metal pin 4. In order to hermetically seal the semiconductor element 9 against the outside air, a metal lid 6 is provided so as to be in contact with the plastic package body 1.

In the plastic package for mounting a semiconductor element thus configured, the difference in thermal expansion coefficient between the semiconductor element 9 and the heat dissipation board 3 and the difference in thermal expansion coefficient between the plastic package body 1 and the heat dissipation board 3 are small. Therefore, the stress due to the difference in thermal expansion can be relaxed, and peeling can be prevented.

FIG. 2 is a diagram schematically showing an enlarged cross section of the bonding interface between the heat dissipation board 3 and the semiconductor element 9. Referring to FIG. 2, the center line average surface roughness (Ra) of heat dissipation board 3 is Ra =
It is controlled to a state of 0.2 to 1.5 μm. Therefore,
At the joint between the heat dissipation substrate 3 and the semiconductor element 9, it is expected that the joint property will be improved by the anchor effect. Further, the same effect can be expected at the bonding interface between the heat dissipation board 3 and the plastic package body 1. If the center line average surface roughness of the surface of the heat dissipation substrate is Ra> 1.5 μm, there is a problem in quality and reliability such as foaming from the gold-plated portion due to heat treatment when mounting a semiconductor element. Further, when Ra <0.2 μm, a sufficient anchor effect cannot be obtained with this copper composition, resulting in a problem in bondability. Further, even if the center line average surface roughness of the surface of the heat dissipation substrate 3 is 0.2 to 1.5 μm, copper having a copper composition of less than 25% by weight or more than 40% by weight is used.
With the tungsten alloy, the copper-molybdenum alloy, and the copper-molybdenum-tungsten alloy, the element peeling due to the heat cycle or the junction between the semiconductor element 9 and the heat dissipation board 3 or the junction between the plastic package body 1 and the heat dissipation board 3 is performed. The problem of poor bonding occurs.

The shape of the heat dissipation board 3 is not limited to the flat plate type shown in FIG. Groove 13a as shown in FIG.
However, the heat dissipation substrate 13 may be formed around the semiconductor element 19 to be joined. Further, as shown in FIG. 4, the portion 23a of the heat dissipation substrate to which the semiconductor element 29 is joined may be projected more than the portion 23b to which the plastic package body 21 is joined.

Also, the material of the plastic package body 1 is not limited, and known insulators such as glass / cloth-epoxy resin, glass / cloth-polyimide resin, glass / cloth-fluorine resin, paper phenol resin. Alternatively, an insulator formed of glass triazine resin or the like and provided with copper wiring (copper-clad laminated multilayer board) may be used.
Further, a build-up board may be used in which a photosensitive resin (insulating layer) is applied to the copper-clad laminate, exposure, development, and hole formation for vias are performed, and then copper plating, wiring pattern formation, and interlayer connection are repeated.

Further, regarding the plastic package structure, the above-mentioned multilayer PGA type (Pin Grid) is also used.
It is not limited to the Array Type, but is a known surface mountable BGA type (Ball Grid).
Array Type), TCP type (Tape)
Carrier Package Type) or the like, or may be applied to an MCM (MultiChip Module) in which a plurality of semiconductor elements are mounted in one package.

Next, a method of manufacturing the semiconductor element mounting plastic package according to one embodiment of the present invention shown in FIG. 1 will be described.

First of all, copper is removed by a sintering method or an infiltration method.
Copper-tungsten alloys, copper-molybdenum alloys containing -40% by weight and copper-molybdenum-tungsten alloys containing 25-40% by weight of copper are produced. Here, the infiltration method is
It refers to a method of infiltrating copper into a porous sintered body of tungsten or molybdenum disclosed in JP-B-2-31863. Next, this alloy is machined into a predetermined size. Then, the surface of the alloy is ground or blasted to have a center line average surface roughness of 0.2 to 1.5 μm, and the surface is subjected to predetermined plating to complete the heat dissipation substrate 3. Further, a plastic package body 1 of a multilayer plastic substrate formed by a known manufacturing method.
The heat dissipating substrate 3 is joined with resin or solder. In this way, the semiconductor element mounting plastic package shown in FIG. 1 is completed. In such a manufacturing process, complicated manufacturing processes such as the joining integration process shown in FIGS. 7 and 8 can be omitted, and as a result, the manufacturing cost can be reduced.

[0036]

EXAMPLE In order to manufacture a plastic package for mounting a semiconductor element in which a flat type heat dissipation board shown in FIG. 1 is joined, a size of 50 mm × 50 mm × 2 mm, a five-layer structure, and a die attach portion ( Semiconductor element mounting part)
Was manufactured by a subtractive method, with a plastic package body 1 (multilayer plastic substrate) having an opening of a flat area of 15 mm × 15 mm.

On the other hand, as the material of the flat plate type heat dissipation substrate 3, 25 to 40 weight parts of copper-tungsten alloy, copper-molybdenum alloy and copper are used with various copper compositions so that the density becomes substantially 100% by the infiltration method. % Copper-Molybdenum-
A tungsten alloy was produced. This alloy is 25mm x 2
It was processed into a substrate shape having a thickness of 5 mm × 1 mm. Table 1 shows material properties of copper-tungsten alloy, copper-molybdenum alloy and copper-molybdenum-tungsten alloy with various copper compositions.

[0038]

[Table 1]

Thereafter, the surface of the heat dissipation substrate manufactured as described above was processed by grinding or blasting to have a center line average surface roughness (Ra) of 0.2 to 1.5 μm. Here, the centerline average surface roughness Ra was measured by tracing on the diagonal line of the heat dissipation substrate with a contact type surface roughness meter.

Next, the heat dissipation board 3 was bonded to the bottom of the plastic package body 1 with resin or solder. Finally,
As final finishing plating, nickel plating and gold plating were applied to the surface of the metal part of the semiconductor element mounting plastic package to obtain a plastic package.

A plurality of samples of the plastic package obtained as described above were subjected to a plating heat resistance test, and then a silicon semiconductor device having a square surface of various sizes on the plastic package body (thickness 0.4 mm). Was mounted via an epoxy adhesive containing a silver filler, and the airtightness and bondability of each package were observed. Furthermore, as a reliability evaluation test, a temperature cycle (-6
5 ° C. to + 150 ° C., 1000 cycles), and airtightness and bondability were confirmed again.

The heat resistance of plating was 300 ° C. × 1 min. It was heated and observed by an optical microscope for the presence or absence of plating foaming on the heat dissipation substrate. Regarding the airtightness, the leak rate was examined by a sneifer method using He gas, and 1 × 10 ⁻⁸ atm · cc /
A value of sec or less was judged to be good. As for the bondability, SE
M (Scanning Electron Microscope) and an optical microscope were used for observation, and the presence or absence of peeling was evaluated. For comparison, a conventional plastic package with a copper heat dissipation board was also examined in the same manner. The results of Samples 1 to 36 are shown in Table 2. Table 3 shows the results of Samples 37 to 59.

[0043]

[Table 2]

[0044]

[Table 3]

In Tables 2 and 3, "plastic part" means a connecting part between the plastic package body and the heat dissipation board, and "element part".
Indicates a connecting portion between the semiconductor element and the heat dissipation board. In Tables 2 and 3, "before test" and "after test" show the results before and after the reliability evaluation test. In Tables 2 and 3, “◯” means good, and “x” means bad.
Further, in Tables 2 and 3, "length or width of silicon semiconductor element" indicates the length of one side of the square surface of the silicon semiconductor element.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a semiconductor element mounting plastic package according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a portion II in FIG.

FIG. 3 is a sectional view of a semiconductor element mounting plastic package according to another aspect of the present invention.

FIG. 4 is a sectional view of a semiconductor element mounting plastic package according to still another aspect of the present invention.

FIG. 5 is a sectional view of a conventional semiconductor element mounting plastic package.

FIG. 6 is a cross-sectional view of a conventional improved plastic package for mounting a semiconductor device.

FIG. 7 is a perspective view showing a first step of a method of manufacturing the heat dissipation board of the conventional semiconductor element mounting plastic package shown in FIG. 6.

FIG. 8 is a perspective view showing a second step of the method for manufacturing the heat dissipation board of the conventional semiconductor element mounting plastic package shown in FIG. 6;

[Explanation of symbols]

 1,11,21 Plastic package body 3,13,23 Heat dissipation board 7,17,27 Bonding layer 8,18,28 Bonding layer 9,19,29 Semiconductor element

Front page continued (72) Inventor Masahiro Omachi 1-1-1 Kunyokita, Itami City, Hyogo Prefecture Sumitomo Electric Industries, Ltd. Itami Works

Claims (6)

[Claims] 1. A semiconductor comprising: a heat dissipation substrate; and a plastic package body surrounding a semiconductor element bonded to the heat dissipation substrate with a bonding layer interposed therebetween and bonded to the heat dissipation substrate with a bonding layer interposed. In the device mounting plastic package, the heat dissipation substrate may include a copper-tungsten alloy containing 25 to 40% by weight of copper, a copper-molybdenum alloy containing 25 to 40% by weight of copper, and a copper-molybdenum alloy containing 25 to 40% by weight of copper.
At least one selected from the group consisting of tungsten alloys
And a surface of the heat dissipation substrate, which is bonded to the semiconductor element and the plastic package body, has a thickness of 0.2 to 1.5 μm.
A plastic package for mounting a semiconductor element, which has a center line average surface roughness (Ra) within the range. 2. The plane area of the semiconductor element is 7 mm × 7
The plastic package for mounting a semiconductor device according to claim 1, wherein the plastic package is larger than mm. 3. The plastic package for mounting a semiconductor device according to claim 1, wherein a groove is formed on a surface around a portion of the heat dissipation substrate to which the semiconductor device is joined. 4. The surface of the part of the heat dissipation board to which the semiconductor element is joined protrudes from the surface of the part of the heat dissipation board to which the plastic package body is joined. 2. A plastic package for mounting a semiconductor element according to 2. 5. A method of manufacturing a plastic package for mounting a semiconductor device, in which a semiconductor package bonded to a heat dissipation substrate is surrounded by a plastic package body, wherein the heat dissipation substrate is a copper-tungsten alloy containing 25 to 40% by weight of copper. Using at least one alloy selected from the group consisting of a copper-molybdenum alloy containing 25 to 40% by weight of copper and a copper-molybdenum-tungsten alloy containing 25 to 40% by weight of copper, the semiconductor element and the plastic package After the surface of the heat dissipation board to be joined to the main body has a center line average surface roughness (Ra) of 0.2 to 1.5 μm, the heat dissipation board is attached to the plastic package body with a bonding material interposed. Characterized by joining,
Manufacturing method of plastic package for mounting semiconductor device. 6. The method according to claim 5, wherein the step of bringing the surface of the heat dissipation substrate into a state where the center line average surface roughness (Ra) is 0.2 to 1.5 μm is performed by either grinding or blasting. A method for manufacturing a plastic package for mounting a semiconductor device as described above.