JP2002226925A - Method for manufacturing composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and inexpensively manufacture a composite material in which ceramic powders are a disperse phase and a metal is a matrix phase and the expansion coefficient of which differs in two stages in a thickness direction. SOLUTION: SiC powder 4 to be a disperse phase 3 on the high-density side is packed in a metal mold 5. Then melt 6 prepared by mixing the SiC powder 4 to be the disperse phase 3 on the low-density side with an aluminum alloy in a molten state is supplied in a pressurized state. After the aluminum alloy in the prescribed quantity enough to practically fill the space between the SiC powder 4 particles and coat the SiC powder 4 particles on the opening side of the metal mold 5 is poured into the metal mold 5, pressure equal to that in the case of die casting is applied as a feeder-head pressure. After the molten metal in the supplied melt 6 is infiltrated into the spacing between the SiC powder 4 particles in a packed state, the metal mold 5 is cooled to solidify and cool the melt. Then the metal mold 5 is disassembled and the composite material 1 is taken out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a composite material suitable for use as, for example, a radiator plate, and more particularly, to a matrix phase of metal and a dispersed phase of ceramic powder.
The present invention also relates to a method for producing a composite material in which the volume fraction of the dispersed phase changes in the thickness direction of the composite material.

[0002]

2. Description of the Related Art When a heat sink (heat sink) of a semiconductor device is made of metal, the difference in coefficient of thermal expansion between the metal and the semiconductor device is large, and the semiconductor device may be damaged.
A radiator plate in which ceramic powder (ceramic fine particles) is dispersed in a metal matrix phase, for example, Si
A composite material in which C powder is dispersed in an aluminum substrate is known. When using the heat sink made of the composite material, the semiconductor device and the like are not mounted directly on the heat sink but mounted on the heat sink via an insulating substrate. The heat sink is S
Since the content (volume ratio) of iC is as large as 60 to 70%,
Even if you try to join it to the insulating substrate with solder or brazing material,
Since the wettability of the solder or the like is poor, the surface is subjected to a surface treatment such as a Ni plating process and then joined to the insulating substrate by the solder or the like. However, when the content (volume ratio) of SiC in the surface layer of the composite material is large, there is a problem that the adhesion of the plating is poor and the machining is difficult. further,
Even if it is joined to the insulating substrate via solder, etc., the thermal expansion coefficient of the heat sink and the thermal expansion coefficient of the insulating substrate are not matched, so the temperature cycle, that is, the change due to the thermal expansion and contraction due to the temperature change, Poor reliability when received.

As a method for solving this problem, as a composite material constituting a heat sink, the ceramic content in the inner layer portion is increased and the ceramic content in the surface layer portion is reduced, that is, bonding to the insulating substrate of the heat sink. It has been proposed to make the thermal expansion coefficient on the side to be made close to the thermal expansion coefficient of the insulating substrate. For example, Japanese Patent Application Laid-Open No. H11-135896 discloses a process of forming a thermal expansion suppressing material in which the entire surface or a part of the surface layer has a higher porosity than that of the inner layer, Heating the above, and placing the heated thermal expansion suppressing material in a mold cavity maintained at a temperature of 200 ° C. or higher and the melt solidification temperature or lower, and injecting the molten metal into the mold cavity under pressure. There has been proposed a method for manufacturing a heat radiation substrate provided. A binder is used when forming the preform of the thermal expansion suppressing material.

Japanese Patent Application Laid-Open No. 10-280067 proposes a method for producing a composite material in which a preform formed by mixing a matrix metal powder and a ceramic as a composite material is impregnated with a molten matrix metal and solidified. Have been. When forming the preform, a binder is used. It also discloses that ceramic powder is used as the composite material and that the volume ratio of the preform is inclined.

[0005]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open
According to the methods disclosed in Japanese Patent No. 280067 and Japanese Patent Application Laid-Open No. 11-135896, after a preform (preformed body) is formed, it is necessary to impregnate (cast) the molten metal into the preform by high-pressure casting. Accordingly, the manufacturing cost is increased by molding the preform. In addition, since a binder is used when molding the preform, there is a problem that even if the binder is burned out during the impregnation with the molten metal, the physical property value of the manufactured composite material is deteriorated.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a composite having a ceramic powder as a dispersed phase (reinforcing material), a metal as a matrix phase, and a different expansion coefficient in the thickness direction. An object of the present invention is to provide a method for producing a composite material, which can produce a material simply and at low cost.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a metal is used as a matrix phase, a ceramic powder is used as a dispersed phase, and the volume ratio of the dispersed phase is set to the composite material. A method for producing a composite material that changes in a thickness direction, wherein after filling the powder in a molding die, a molten metal of the matrix phase is formed by mixing a powder of the same type of ceramic as the powder with the molding die. It is supplied under pressure and solidified.

In the present invention, in a state where the ceramic powder is filled in the molding die, a molten metal in which a ceramic powder of the same kind as the powder is mixed with a molten metal of a metal to be a matrix phase is supplied into the molding die in a pressurized state. Is done. After the molten metal in the molten metal mixed with the ceramic powder penetrates into the gaps between the filled ceramic powders, the molten metal is solidified to form a composite material. The volume ratio of the dispersed phase in the thickness direction of the composite material changes in two stages, that is, a portion substantially equal to the volume ratio at the time of filling the ceramic powder before supplying the molten metal and a portion smaller than the volume ratio. The volume ratio of the ceramic powder in the portion formed from the molten metal side is larger than the volume ratio in the molten metal before supply. The amount of the molten metal that enters the gap between the ceramic powders filled in the molding die can be known in advance from the volume ratio of the filled ceramic powders. Therefore, by adjusting the volume ratio of the ceramic powder in the molten metal mixed with the ceramic powder in accordance with the volume ratio of the ceramic powder in the portion formed from the molten metal side in the composite material after the production, The volume ratio of the dispersed phase in the material can be set to a desired value.

According to a second aspect of the present invention, in the first aspect of the present invention, the powder mixed with the molten metal has a larger particle diameter than the powder filled in the molding die. I have. Therefore, in the present invention, since the particle size of the ceramic powder mixed in the molten metal is larger than the particle size of the powder filled in the molding die, the gap between the ceramic powder filled with the molten metal supplied to the molding die is pressed. When the ceramic powder infiltrates, the ceramic powder in the molten metal does not enter the gap, but only the molten metal enters. As a result, when the melt is solidified, the volume ratio of the dispersed phase in the thickness direction of the composite material becomes the same as the volume ratio at the time of filling the ceramic powder before supplying the melt. Further, the volume ratio of the ceramic powder in the portion formed from the molten metal side can be easily adjusted to a target value.

According to the third aspect of the present invention, the metal is a matrix phase, the ceramic powder is a dispersed phase, and the volume ratio of the dispersed phase is at least 2 in the thickness direction of the composite material.
A method for producing a composite material that changes in stages, wherein the powder is filled in a state having a density difference of at least two stages from a side where a molten metal is supplied into a molding die toward an opposite side, and then becomes the matrix phase. The molten metal in which the metal has been melted is supplied into the mold under pressure and solidified.

According to the present invention, when the molten metal is supplied in a pressurized state after the ceramic powder has been filled in the molding die, the molten metal is filled in the gap between the filled ceramic powders with at least two levels of density difference. Penetrate. Then, when the molten metal is solidified, the composite material in which the volume ratio of the dispersed phase changes in at least two stages in the thickness direction of the composite material corresponding to the volume ratio at the time of filling the ceramic powder before supplying the molten metal is obtained. can get.

According to a fourth aspect of the present invention, there is provided a method for producing a composite material using a metal as a matrix phase and a ceramic powder as a dispersed phase, wherein the side opposite to the side where molten metal is supplied in a molding die is provided. After filling the powder into the molding die in a state where a metal plate of the same kind as the metal is arranged, a molten metal in which the metal to be the matrix phase is melted is supplied into the molding die in a pressurized state. At least the side facing the powder is melted, a part of the powder is mixed with the molten metal, and then solidified.

Therefore, according to the present invention, the molten metal supplied in a pressurized state into the mold penetrates into the gap between the ceramic powders filled to a desired density and is arranged on the side opposite to the molten metal supply side. It comes into contact with the metal plate. Then, the metal plate is melted by the heat of the molten metal, and a part of the ceramic powder filled in the metal plate is mixed with a part of the metal plate melted by the pressure of the molten metal. As a result, after the molten metal is solidified, a composite material is obtained in which the volume ratio of the ceramic powder on the side where the metal plate is disposed is small and the volume ratio of the ceramic powder in the portion where the ceramic powder is filled is large.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the metal plate is disposed at the bottom of the molding die, and the molten metal is supplied from above. Therefore,
According to the present invention, the filling of the powder and the supply of the molten metal can be performed smoothly.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the metal is aluminum or an aluminum alloy. Therefore,
According to the present invention, it is possible to secure the heat conductivity required for use as a heat radiator for electronic components such as semiconductor devices, which is lightweight. In addition, since the melting temperature of the metal is lower than when copper is used as the metal, the amount of energy required during manufacturing can be reduced.

In the invention according to claim 7, in the invention according to any one of claims 1 to 6, the ceramic is silicon carbide (SiC). Therefore, according to the present invention, it is easy to make the coefficient of thermal expansion close to the coefficient of thermal expansion of the semiconductor device in a state where the thermal conductivity of the composite material is high, and obtain a ceramic powder having desired physical properties (high thermal conductivity). Easy to do.

[0017]

(First Embodiment) A first embodiment of the present invention will be described below with reference to FIG.

FIG. 1C is a schematic cross-sectional view of a composite material manufactured by the manufacturing method of this embodiment. Composite material 1
Is formed in such a configuration that a metal is used as a matrix phase 2 and a ceramic powder is used as a dispersed phase 3. As the metal of the matrix phase 2, a metal having a high thermal conductivity, that is, a metal having a thermal conductivity equal to or higher than that of aluminum is used. In this embodiment, the metal of the matrix phase 2 is aluminum or aluminum alloy (hereinafter, referred to as aluminum alloy).
Aluminum alloy). Silicon carbide powder (SiC powder 4) is used as the ceramic powder constituting the dispersed phase 3. The dispersed phase 3 is configured such that its volume ratio, that is, the volume ratio of the SiC powder 4 changes in two steps in the thickness direction of the composite material 1 (the vertical direction in FIG. 1C).

In this embodiment, a low-density portion 1a having a small volume ratio of SiC powder 4 is formed on the surface layer side of composite material 1 on the upper side in FIG. 1C, and S is formed on the inner layer side on the lower side.
The high-density portion 1b in which the volume ratio of the iC powder 4 is increased is formed. The particle size and volume ratio of the SiC powder 4 are set in accordance with the characteristics (physical properties) required for the composite material, but the high-density portion 1b is formed such that the volume ratio of the SiC powder 4 is, for example, about 70 to 75%. I have. S to be dispersed phase 3 of high-density portion 1b
As the iC powder 4, a mixture of coarse particles and fine particles is used, and coarse particles having a particle diameter of about 100 μm and fine particles having a particle diameter of about 10 μm are used. The amount of use of coarse particles and fine particles is set so that packing can be carried out closest. As the SiC powder 4 serving as the low-density portion 1a, a powder having a particle diameter larger than that of the coarse particles is used. The volume ratio of the low density portion 1a is set according to the purpose.

Next, a method of manufacturing the composite material 1 configured as described above will be described with reference to FIGS. 1 (a) and 1 (b). The mold 5 as a molding die is a bottomed square cylindrical shape, is configured to be disassembled into a plurality of molding die constituent pieces 5a and 5b, and is fixed by bolts and nuts (not shown). As a material of the mold 5, a metal having higher rigidity than an aluminum alloy, for example, iron is used.

When the composite material 1 is manufactured using the mold 5, first, as shown in FIG.
The inside is filled with the SiC powder 4 to be the dispersed phase 3 on the inner layer side, that is, a mixture of coarse particles and fine particles. In the drawing, the size of the particles is shown without distinction. Next, SiC powder 4 to be the dispersed phase 3 on the surface layer side, that is, molten metal 6 mixed with SiC powder 4 having a particle size larger than the coarse particles is supplied (injected) to the molten aluminum alloy in a pressurized state. SiC
After a predetermined amount of aluminum alloy covering the SiC powder 4 on the opening side of the mold 5 is injected into the mold 5 while substantially filling the gap of the powder 4, a pressure similar to that of die casting is used as a feeder pressure (for example, , Several tens MPa to one hundred MPa) are applied. That is, so-called high-pressure casting is performed. After the molten metal in the supplied molten metal 6 penetrates into the gaps between the filled SiC powders 4, the mold 5 is cooled to solidify and cool the molten metal. 1 is taken out.

The volume ratio of the dispersed phase 3 on the inner layer side (high-density portion 1b) of the composite material 1, that is, the volume ratio of the SiC powder 4, is
Is almost the same as the volume ratio at the time of filling the SiC powder 4 before the supply. Further, the volume ratio of the SiC powder 4 on the surface layer side (low density portion 1a) is larger than the volume ratio in the molten metal 6 before the supply. The amount of the molten metal entering the gap between the SiC powders 4 filled in the mold 5 can be known in advance from the volume ratio of the SiC powders 4 filled. Therefore, by adjusting the volume ratio of the SiC powder 4 in the molten metal 6 mixed with the SiC powder 4 in accordance with the volume ratio of the low density portion 1a, the volume ratio of the low density portion 1a in the composite material 1 is reduced. It is set to the desired value.

The composite material 1 manufactured as described above
Is used, for example, as a heat dissipation member for a semiconductor device.
In this case, the composite material 1 is joined via a solder or a brazing material such that the low-density portion 1a on the surface layer faces the insulating substrate made of ceramics. When the thickness of the composite material 1 is formed to a predetermined value, the surface layer is cut.

Although the shape of the composite material 1 is schematically shown in FIG. 1 as a quadrangular prism, the heat dissipating member is generally in the form of a flat block (plate), and is generally adapted to the desired shape of the heat dissipating member. By using the mold 5 having a different shape, a composite material 1 having a desired shape is formed.

This embodiment has the following effects. (1) After filling a molding die (die 5) with SiC powder 4 (ceramic powder), a molten metal 6 serving as a matrix phase 2 mixed with SiC powder 4 is supplied under pressure and solidified. Thereby, the composite material 1 in which the volume ratio of the SiC powder 4 changes in the thickness direction of the composite material 1 can be easily manufactured. Therefore, since the desired composite material 1 can be formed without forming the preform, the productivity can be improved and the manufacturing cost can be reduced as compared with the method of forming the preform. Further, since a binder used at the time of preform molding is not required, deterioration (decrease) of the physical properties of the composite material 1 can be prevented.

(2) SiC powder 4 mixed with molten metal 6
Used is larger in particle size than the SiC powder 4 filled in the mold 5. Therefore, when the molten metal 6 mixed with the SiC powder 4 is supplied into the mold 5 in a pressurized state, the molten metal 6 is prevented from entering the gap between the SiC powder 4 filled with the SiC powder 4 and the molten metal 6 together. Is done. as a result,
The volume ratio of the SiC powder 4 on the inner layer side of the manufactured composite material 1 can be made almost the same as the value at the time of filling, and the inner layer side (high-density portion 1)
b) and the volume ratio of the SiC powder 4 on the surface layer side (low-density portion 1a) can be easily adjusted.

(3) SiC previously filled in the mold 5
Since a mixture of coarse particles and fine particles is used as the powder 4, the filling ratio, that is, the volume ratio is larger than when the SiC powder 4 has a constant particle diameter. Becomes easier.

(4) Since the volume ratio of the SiC powder 4 on the surface layer of the composite material 1 is small, cutting on the surface layer becomes relatively simple. Therefore, when the thickness of the manufactured composite material 1 is adjusted, by cutting the surface layer side, the thickness can be easily adjusted as compared with the SiC powder 4 having a uniform and large volume ratio as a whole.

(5) Since a metal having a thermal conductivity equal to or higher than that of aluminum is used as the matrix phase 2, it is suitable for use as a heat radiating material for electronic parts such as semiconductor devices. .

(6) Since the matrix phase 2 is an aluminum alloy, it is possible to secure necessary heat conductivity at a low weight, and since the melting temperature is lower than that of other metals having high heat conductivity such as copper, the casting is performed. Energy consumption at the time can be reduced.

(7) Since the SiC powder 4 is used as the ceramic powder constituting the dispersed phase 3, the filling rate of the dispersed phase 3 is increased to reduce the thermal expansion coefficient of the composite material 1 to the thermal expansion coefficient of the semiconductor device. The thermal conductivity of the composite material 1 can be increased even when the distance is closer to the above, and the heat radiation efficiency when used as a heat radiating material is improved.

(8) Since powder is used instead of fiber as the reinforcing material, it is easier to fill the fiber at a higher density than fiber. It is more easily available than fiber. (9) Since the molten metal is impregnated by high pressure casting, shrinkage cavities and gas defects are reduced as compared with die casting.

(Second Embodiment) Next, a second embodiment will be described with reference to FIG. In this embodiment, at the time of manufacturing the composite material 1, ceramic powder (SiC) is used as a molten metal.
The point of using the molten metal 7 in which the powder 4) is not mixed and the point of filling the mold 5 with the SiC powder 4 so that the volume ratio thereof changes in two steps in the thickness direction of the composite material. It is very different from the form. The same parts as those of the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 2C is a schematic sectional view of the composite material 1 manufactured by the manufacturing method according to this embodiment. Composite material 1
2 (c), there is a metal layer 2a having a volume fraction of 0% of the SiC powder 4 solidified in a state where the molten metal 7 covers the filling layer of the SiC powder 4.

When manufacturing this composite material 1, FIG.
As shown in (a), first, a mold 5 is filled with SiC powder 4 in a state having a two-stage density difference from the side supplying the molten metal to the opposite side. In this embodiment, the SiC powder 4 is filled so that the inner layer side (the bottom side of the mold 5) has a high density and the surface layer side (the opening side of the mold 5) has a low density.

The SiC powder 4 packed at high density has coarse particles (particle diameter of about 100 μm) as in the above embodiment.
And a mixture of fine particles (with a particle diameter of about 10 μm) and a packing density of about 70 to 75%. The filling density of the SiC powder 4 on the surface layer to be filled at a low density is set according to the purpose, and the SiC powder 4 may be a mixture of particles having different particle diameters, or a case of using only the same particle diameter. is there.

Next, as shown in FIG. 2B, a molten metal 7 made of an aluminum alloy in a molten state is injected under pressure. After the supplied molten metal 7 penetrates into the gaps between the filled SiC powders 4, the mold 5 is cooled to solidify and cool the molten metal 7, the mold 5 is decomposed, and the composite material 1 is taken out. It is. Then, the composite material 1 shown in FIG. 2C is obtained. The obtained composite material 1 is used as a heat dissipating member for a semiconductor device by removing the surface metal layer 2a by cutting. In some cases, it is used with the metal layer 2a left thin.

This embodiment has the following effects in addition to the effects similar to (4) to (9) of the above embodiment. (10) After filling the SiC powder 4 in the mold 5 from the side where the molten metal 7 is supplied to the opposite side with a two-stage density difference, the molten metal 7 serving as a matrix phase is supplied under pressure. By solidifying the composite material, the composite material 1 in which the volume ratio changes at a desired value can be easily manufactured.

(11) Since the metal layer 2a is formed on the surface layer (low density portion 1a side) where the volume ratio of the SiC powder 4 is small, cutting is performed so that the metal layer 2a remains thin on the surface layer side of the composite material 1. By using it, the bonding strength to solder or the like is improved.

(12) Since a mixture of coarse particles and fine particles is used as the SiC powder 4 filled into the mold 5 at a high density, a SiC powder 4 having a constant particle diameter is used. As compared with the case, it is easy to fill the filling rate, that is, the volume ratio in a large state.

(Third Embodiment) Next, a third embodiment will be described with reference to FIG. In this embodiment, the point that the mold 5 is filled with the SiC powder 4 at a constant high density is the first point.
This is the same as the embodiment. However, the SiC powder 4 is not mixed with the molten metal, but the metal plate 8 disposed in the mold 5 is melted with the molten metal 7 and a part of the filled SiC powder 4 is mixed with the molten metal to reduce the molten metal. The difference is that the density portion 1a is formed.

When manufacturing the composite material 1, first, FIG.
As shown in (a), the mold 5 is placed in a state where a metal plate 8 of the same type as the matrix metal (aluminum alloy) is arranged at the bottom of the mold 5, that is, on the side opposite to the side where the molten metal is supplied in the mold 5.
Is filled with SiC powder 4 to a predetermined density. Next, the molten metal 7 in which the matrix metal is melted is supplied into the mold 5 in a pressurized state. As shown in FIG. 3B, the molten metal 7 is supplied in an amount that covers the filled SiC powder 4. Then, at least the side of the metal plate 8 opposed to the SiC powder 4 is melted and
After a part of the C powder 4 is mixed with the molten metal, the mold 5 is cooled and the molten metal 7 is solidified and cooled. Then, the mold 5 is decomposed and the composite material 1 is taken out.

Then, the solidified portion of only the melt 7 supplied so as to cover the filled SiC powder 4 is cut and removed to form the composite material 1 as shown in FIG. 3 (c). That is, the SiC powder 4 is formed on the surface layer (the lower side of FIG. 3C).
A low-density portion 1a having a small volume ratio of
The composite material 1 having the high-density portion 1b having a large volume ratio of the C powder 4 is obtained. The volume ratio of the SiC powder 4 in the low-density portion 1a is adjusted by the thickness of the metal plate 8, the filling density of the SiC powder 4 before the supply of the molten metal 7, the magnitude of the pressing force when supplying the molten metal 7, and the like. .

In this embodiment, (3) to (9) of the first embodiment and (11) and (1) of the second embodiment
In addition to the effect similar to 2), the following effect is obtained. (13) By adjusting the thickness of the metal plate 8 and the filling amount of the SiC powder 4, the volume ratio of the low-density portion 1a can be adjusted.

The embodiment is not limited to the above, and may be configured as follows, for example. When the SiC powder 4 is packed at a high density to constitute the dispersed phase 3 having a large volume ratio, the SiC powder 4 having coarse particles is used.
Do not use a mixture of two kinds of fine particles and SiC powder 4 and use a mixture of particles having the same particle diameter or a mixture of three or more kinds of particles having different particle roughness. You may.

In the first embodiment, the particle size of the SiC powder 4 to be mixed with the molten metal 6
A powder smaller than the particle diameter of the C powder 4 may be used. However, those having a large particle diameter are preferred.

In the first embodiment, the filling density of the SiC powder 4 to be filled in the mold 5 may be set in advance so that the bottom side is high and the opening side is low. In this case, a composite material 1 in which the volume ratio of the dispersed phase 3 changes in three steps in the thickness direction of the composite material 1 is obtained.

In the second embodiment, the mold 5 is filled so that the filling density (volume ratio) of the SiC powder 4 to be filled in advance is changed in three or more steps in the thickness direction of the composite material 1 in order. You may. However, when the composite material 1 is used as a heat sink, it is sufficient to change the thermal expansion coefficient of the heat sink to the thermal expansion coefficient of the insulating substrate in two stages in order to match the thermal expansion coefficient.

In the second embodiment, when filling the mold 5 with the SiC powder 4, the bottom side may be filled with low density instead of filling the bottom side with high density. In this case, the amount of the molten metal 7 supplied into the mold 5 is increased, the metal layer 2a is formed thick on the opening side, and the metal phase is processed with fins, thereby providing a heat radiation member with improved heat radiation efficiency. Function.

In the second embodiment, when filling the mold 5 with the SiC powder 4, the filling density may be symmetrical so that the bottom side and the opening side are low and the middle part is high. In this case, a composite material in which the volume ratio of the dispersed phase 3 is symmetric in the thickness direction can be obtained, so that there is no possibility that the mounting surface is mistaken when used as a heat sink.

The metal of the matrix phase 2 only needs to have a thermal conductivity equal to or higher than that of aluminum.
Not limited to aluminum alloys, other metals such as copper may be used. In this case, since the heat conductivity is higher than that of the aluminum alloy, the heat dissipation efficiency is improved when the composite material 1 is used as a heat dissipation material.

A ceramic powder other than the SiC powder 4 may be used as the ceramic powder. The method of using the composite material 1 is not limited to the heat dissipation member of the semiconductor device or the electronic component mounting base material. When used in applications other than heat dissipating members, other materials having high hardness, such as boron nitride (B
N), titanium carbide, tungsten carbide, or the like may be used.

The mold is not limited to a metal mold, but may be a ceramic mold. The invention (technical idea) grasped from the embodiment will be described below.

(1) In the invention according to any one of claims 1, 2, 4, and 5, the powder to be charged into the molding die before the molten metal is supplied under pressure is a mixture of coarse particles and fine particles. Is used.

(2) In the invention according to claim 1 or 2, a mixture of coarse particles and fine particles is used as the powder filled in the molding die, and the powder mixed with the molten metal is Those having almost the same particle size are used.

(3) A composite material in which metal is a matrix phase, ceramic powder is a dispersed phase, and the volume ratio of the dispersed phase changes in the thickness direction of the composite material. A mixture of coarse particles and fine particles is used as a large part of the powder, and a particle having a larger particle diameter than the coarse particles is used as the part of the powder having a small volume ratio.

[0057]

As described in detail above, claims 1 to 7 are provided.
According to the invention described in (1), it is possible to easily and inexpensively produce a composite material having a different expansion coefficient in a thickness direction by using a ceramic powder as a dispersed phase (reinforcement) and a metal as a matrix phase.

[Brief description of the drawings]

FIGS. 1A and 1B show a first embodiment, and FIG.
FIG. 2 is a schematic cross-sectional view of a state where iC powder is filled, (b) is a schematic cross-sectional view of a state where a molten metal is supplied, and (c) is a schematic cross-sectional view of a composite material.

FIGS. 2A and 2B show a second embodiment, in which FIG.
FIG. 2 is a schematic cross-sectional view of a state where iC powder is filled, (b) is a schematic cross-sectional view of a state where a molten metal is supplied, and (c) is a schematic cross-sectional view of a composite material.

3A and 3B show a third embodiment, wherein FIG. 3A is a schematic cross-sectional view showing a state in which a metal plate is set in a mold and filled with SiC powder 4, and FIG. 3B is a state in which a molten metal is supplied. FIG. 2 is a schematic cross-sectional view, and (c) is a schematic cross-sectional view of a composite material.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Composite material, 2 ... Matrix phase, 3 ... Disperse phase, 4 ...
SiC powder as ceramic powder, 5 as a mold, 6, 7 as molten metal, 8 as metal plate.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kyoichi Kinoshita 2-1-1 Toyota-cho, Kariya-shi, Aichi Prefecture Inside Toyota Industries Corporation (72) Inventor Eiji Kawano 2-1-1 Toyota-cho, Kariya-shi, Aichi Prefecture Shares F-term in Toyota Industries Corporation (reference) 4K020 AA22 AB01 AC01 BA08 BB26

Claims (7)

[Claims] 1. A method for producing a composite material, wherein a metal is a matrix phase, a ceramic powder is a dispersed phase, and a volume ratio of the dispersed phase changes in a thickness direction of the composite material.
Production of a composite material in which after filling the molding powder with the powder, a molten metal of the matrix phase, which is a mixture of the same type of ceramic powder as the powder and is supplied to the molding die under pressure, is solidified. Method. 2. The method for producing a composite material according to claim 1, wherein the powder mixed with the molten metal has a larger particle diameter than the powder filled in the molding die. 3. A method for producing a composite material, wherein a metal is a matrix phase, a ceramic powder is a dispersed phase, and a volume ratio of the dispersed phase changes in at least two steps in a thickness direction of the composite material. After filling the powder in a state having a density difference of at least two steps from the side where the molten metal is supplied into the mold to the opposite side, the molten metal in which the matrix phase metal is melted is pressed into the molding die. A method for producing a composite material which is supplied and solidified by the method. 4. A method for producing a composite material using a metal as a matrix phase and a ceramic powder as a dispersed phase, wherein a metal plate of the same type as the metal is provided on a side opposite to a side in which a molten metal is supplied in a molding die. After filling the molding die with the powder in the arranged state, a molten metal in which the matrix phase metal is melted is supplied into the molding die in a pressurized state, and at least a side of the metal plate facing the powder. A method for producing a composite material in which a part of the powder is melted, a part of the powder is mixed with the molten metal, and then solidified. 5. The method for manufacturing a composite material according to claim 4, wherein the metal plate is arranged at a bottom of the molding die, and the molten metal is supplied from an upper portion. 6. The method for producing a composite material according to claim 1, wherein the metal is aluminum or an aluminum alloy. 7. The ceramic is made of silicon carbide (Si).
The method for producing a composite material according to any one of claims 1 to 6, which is C).