JP2003306731A - Method for manufacturing metal matrix composite material, and metal matrix composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a metal matrix composite material by which a metal matrix composite material having high thermal conductivity can be manufactured at an extremely low cost without requiring a high temperature process. <P>SOLUTION: A porous body 11 having a large number of pores 11A is immersed in a plating solution Q prepared by mixing a solution A containing metal as an cation and a solution B containing a reducing agent, or the plating solution is passed through the pores of the porous body. In this way, the metal is precipitated in the pores by the reducing agent to obtain the composite material consisting of the porous body and the metal. In the case where the porous body is very thick, the porous body is partially immersed in the plating solution stepwise to precipitate the metal in the pores. Further, the plating solution is circulated and continuously filtrated through the porous body to precipitate the metal in the pores. <P>COPYRIGHT: (C)2004,JPO

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 metal-based composite material and a metal-based composite material produced by the method, and more particularly to a method for producing a metal-based composite material used for heat sinks for electronic parts. And a metal matrix composite material having high thermal conductivity at low cost.

[0002]

2. Description of the Related Art Conventionally, a heat sink that absorbs heat from an electronic component or element and radiates the heat to the outside has been used as an electronic component on which a semiconductor element such as a semiconductor laser or a microwave element is mounted. Since the conventional electronic parts generate a small amount of heat, the semiconductor device (Si, InP, GaAs) mounted as a heat sink has a low thermal conductivity.
Etc.), Al ₂ O ₃ and AlN, which have similar thermal expansion coefficients, have been used. However, recently, as the amount of information increases, the size and output of semiconductor elements have increased, and the increase in the amount of heat generated has become a problem. Therefore, there is a strong demand for a heat sink material having high thermal conductivity.

As a heat sink material, AlN has a relatively good thermal conductivity and a thermal expansion coefficient close to that of a semiconductor element such as Si or InP. It is difficult to deal with devices having a large coefficient of thermal expansion such as GaAs devices.

Specifically, the coefficient of thermal expansion of various semiconductor materials such as semiconductor elements is 4.2 ppm / K for Si, 4.5 ppm / K for InP, and 5.9 ppm / K for GaAs. It is desirable that the materials for use have similar thermal expansion coefficients. Furthermore, the smaller the Young's modulus of the heat sink material, the smaller the thermal stress generated, which is desirable. Therefore, regarding the physical properties required for the heat sink material, the thermal conductivity is equal to or higher than that of Cu (395 W / mK), and the thermal expansion coefficient is Cu (16.9 ppm /
K) The following are desired.

Materials having the highest thermal conductivity are diamond and c-BN, but they have a small coefficient of thermal expansion (diamond 2.3.
(ppm / K, c-BN 3.7 ppm / K), and these materials have a very large Young's modulus of 830 to 1050 GPa. Therefore, when the heat sink material and the semiconductor element are brazed or used as a device, the heat sink material and the semiconductor element are used. There is a problem in that a large thermal stress is generated and destruction occurs.

As a material having a small coefficient of thermal expansion and a relatively high thermal conductivity, Al-S which is a composite of ceramic and metal.
Metal matrix composite materials including iC have been developed.
However, since the thermal conductivity of Al (about 238 W / mK at room temperature) is low, there is an upper limit to the thermal conductivity of the composite material, and the requirement for high thermal conductivity cannot be satisfied.
Further, instead of Al, Cu having a higher thermal conductivity (see
It is possible to use a metal such as 95 W / mK) or Ag (420 W / mK), but SiC used as a composite material
There is a problem that the original high thermal conductivity of Cu, Ag, etc. cannot be utilized because the wettability with is extremely poor.

[0007] Therefore, the applicant of the present invention has disclosed that a heat sink material having improved wettability with Cu or Ag is disclosed in JP-A-11-
No. 67991 proposes a diamond-Ag-based or diamond-Cu-based composite material. This is because after mixing and molding diamond powder and Ag-Cu-Ti-based powder and heating above the melting point of the alloy, the Ti component diffuses and reacts on the diamond particle surface, and a TiC layer is formed on the surface. It is a thing (heat-bonding method). That is, since the wettability between TiC and molten Cu or molten Ag is high, as a result, the interface between the diamond particles and the metal is brought into close contact, and high thermal conductivity can be obtained.

Further, the applicant of the present invention has disclosed, as a heat sink for semiconductors made of the above metal-based composite material, in Japanese Patent Laid-Open No.
No. 0-223812 proposes a diamond-Ag-based or diamond-Cu-based composite material and a manufacturing method called an infiltration method as a manufacturing method thereof. This is because after mixing and shaping diamond powder and Ag-Cu-Ti-based powder, heating above the melting point of the alloy to form a TiC layer on the surface of diamond particles, and further heating to volatilize Ag and Cu components. To form a porous body, which is impregnated with molten Ag-Cu alloy,
This is to obtain a composite material having a higher relative density and thermal conductivity, which has a higher thermal conductivity than the thermal bonding method.

[0009]

However, the heat sinks for semiconductors disclosed in JP-A-11-67991 and JP-A-10-223812 have high thermal conductivity, but have a high melting point metal such as Ag or higher than their melting points. Since it is heated up to the above, the equipment cost, running cost, etc. at the time of manufacturing become high, and further cost reduction is desired. Further, since an interface reaction layer such as TiC exists at the interface between a metal such as Ag and diamond, it is considered that the thermal conductivity is lowered in this interface layer, and there is still room for improvement.

The present invention has been made in view of the above problems, and does not require a high temperature process and can produce a metal matrix composite material at an extremely low cost, and a method for producing a metal matrix composite material, TiC, etc. It is an object of the present invention to provide a metal-based composite material which does not have the metal carbide of 1) and has a high thermal conductivity and a small thermal expansion coefficient.

[0011]

In order to solve the above problems, the present invention provides a plating solution prepared by mixing a solution A containing a metal as a cation and a solution B containing a reducing agent in a large number of porous bodies. The method for producing a metal-based composite material, comprising: filling the inside of the pores, depositing the metal inside the pores with the reducing agent, and obtaining a composite material including the porous body and the metal. is doing.

The pores of the porous body consist of three-dimensional mesh-like continuous pores communicating with the surface openings of the porous body or a large number of independent pores communicating with the surface openings of the porous body. The liquid is passed from the opening on one surface side through the inside of the pores to the opening on the other surface side.

As a result of intensive studies, the present inventor has used a plating solution in which a solution A containing a metal as a cation and a solution B containing a reducing agent are mixed, and the metal acts on the pore surface of the porous body by the action of the reducing agent. It was found that the metal can be filled inside the pores of the porous body by precipitating into. That is, as long as the metal and the reducing agent are present in the plating solution, the metal is reduced by the reducing action to deposit the metal on the surface of the pores, and the metal is further continuously deposited on the deposited metal surface. By stacking the metal deposits, the inside of the pores can be finally filled with the metal. Thereby, the metal can be densely filled in the pores by a simple method of depositing the metal without using the molten metal. As a result, a composite material of a porous body having a high thermal conductivity and a metal can be manufactured at low cost. Specifically, by depositing a metal in the pores of the porous body having a relative density of the porous body of 40% to 70%, the relative density after the deposition is increased to about 100% of about 88% to 99.2%. ing. The relative density is (1-
Porosity), that is, the volume% of the solid portion excluding the total volume of the hollow holes.

Further, according to this method, since the metal is directly deposited on the surface of the pores, there is no influence of the wettability between the porous body and the metal, and good adhesion between the metal and the porous body is obtained. Obtainable. Therefore, since it is not necessary to allow metal carbide such as TiC to exist at the interface between the porous body and the metal, the thermal conductivity can be further increased.

The solution A and the solution B are mixed in a low temperature region lower than the optimum temperature for the reducing action of the reducing agent, and the deposition of the metal causes the plating solution to be optimal for the reducing action of the reducing agent. It is carried out in a high temperature region heated to various temperatures to control the metal deposition rate. Thus, at the time of deposition, by heating to a temperature optimum for the reducing action, the reducing action of the metal by the reducing agent becomes strong, and the deposition rate of the metal can be increased. On the other hand, by mixing the solution at a low temperature, it is possible to suppress alteration of the plating solution and metal precipitation during mixing,
The deposition efficiency can be further increased. Such temperature control is particularly effective when the pore diameter of the porous body is smaller than 200 μm. The deposition of the metal can be controlled by the concentration of the metal in the plating solution, the type and concentration of the reducing agent, the solvent type of the reducing agent, the pH, and the like.

Specifically, the above metal is an Ag-based metal,
It is preferable that the solution A and the solution B are mixed under a temperature condition of 5 ° C. to 10 ° C. and the deposition of the metal is performed under a temperature condition of 40 ° C. to 50 ° C. By using Ag as the metal, the thermal conductivity of the obtained composite material can be further increased. It should be noted that if the temperature is raised too high, Ag may partially turn black and the thermal conductivity of the composite material may decrease, so the above temperature is preferable.

If the metal is Ag, the solution A is an aqueous solution containing silver nitrate (AgNO ₃ ) and a strong base. Thereby, Ag ions can be efficiently reduced and Ag can be deposited in the pores. Ammonia (NH ₃ ) is preferably used as the strong base. The deposition rate of metallic Ag is 1 if the conditions are well controlled.
It can be increased to about 8 μm / hr. The solution containing Ag ions may be NaAg (CN) ₂ or the like. The metal may be contained as a complex ion solution.

The solution A may contain Cu as an ion together with Ag, whereby the alloy of Ag and Cu can be filled in the pores. Cu ions can be added with copper sulfate or the like. In addition to Cu, A
Metal ions such as 1 may be included, and the metal species and the compounding ratio thereof can be appropriately set according to the required performance.

The above solution B is formalin, NaBH ₄ ,
An alcohol solution or an aqueous solution in which at least one of LiBH ₄ and KBH ₄ is dissolved is used. In addition, as the reducing agent, a solution containing Rochelle salt (C ₄ H ₄ O ₆ NaK), phosphite, hypophosphite, hydrazine, dimethylamine borane, other tetrahydroboric acid, etc. may be used. Good. LiBH ₄ has a high reducing power, but it reacts with water and decomposes. Therefore, LiBH ₄ is preferably an alcohol solution.

Moreover, since the concentration of metal ions and the concentration of the reducing agent in the plating solution decrease due to the deposition of the metal, in order to increase the deposition efficiency, the concentration of the metal and the reducing agent is always high. It is preferable that the plating solution is supplied to the surface of the pores of the porous body.

As a method for filling the pores of the porous body with the plating solution, an immersion method and a filtration method are adopted. In the immersion method,
The porous body is dipped in a plating solution in a plating tank, the inside of the pores of the porous body is filled with the plating solution by vacuuming, and the metal is deposited inside the pores. When the porous body has a relatively large thickness, the partial immersion method and the filtration method are preferably used.

In the partial immersion method, the porous body is gradually immersed in a plating solution by a predetermined thickness to gradually deposit the metal inside the pores of the porous body, and finally to the entire pores. Metal is deposited. That is, when the thickness of the porous body is relatively large, a part of the porous body is immersed in the plating solution, the metal is deposited only in the immersed portion, and then the porous body is gradually deeply submerged, which is repeated. . This method has an advantage that a dense layer can be obtained for each layer and a final dense densification can be obtained because the metal is deposited in each thin layer in the thick porous body. The depth (thickness) of one immersion is preferably 30 μm or more and 100 μm or less, although it depends on the size of the pores of the porous body. This is because if it exceeds 100 μm, it becomes impossible to completely densify it, and if it is less than 30 μm, the number of times of dipping is increased and the efficiency deteriorates. In addition,
Needless to say, when the thickness of the porous body is about 100 μm or less, the entire porous body may be immersed in the plating solution.

In the case of the above-mentioned dipping method, the plating solution is filled in the pores of the porous body by vacuuming, so that the deposition efficiency can be improved. The above vacuum conditions can be set by using an ordinary rotary pump or the like. Vacuum degree is 1 × 1
It may be about 0 ^-3 torr, and a value smaller than this is preferable. The temperature of the plating solution may be raised after the porous body is immersed in the plating solution, or the porous body may be immersed in the plating solution after raising the temperature of the plating solution.

In the above-mentioned filtration method, the plating solution is circulated by a pump, continuously filtered by the porous body, and the plating solution is continuously passed through the pore surface of the porous body to thereby remove the plating solution and the void. The metal is deposited on the surface of the pores by making continuous contact with the surface of the pores. This method of depositing a metal while filtering is particularly effective when the thickness of the porous body is large because the plating solution continuously flows inside the pores of the porous body. That is, by continuously filtering the plating solution with a porous body,
Fresh plating solution can also be supplied into the pores near the center of the porous body in the thickness direction. The filtration step is continued until the closed pores are formed in the porous body due to the deposition of the metal and the filtration cannot proceed any further.

Depending on the size of the pores of the porous body, a composite material having a relative density of almost 100% can be obtained up to a porous body thickness of about 100 μm without using a filtration method. When the thickness exceeds 100 μm, a filtration method is preferably used to increase the relative density.

Further, as a method for bringing the plating solution into contact with the surface of the pores of the porous body, the plating solution is made into a mist with a sprayer or the like and continuously sprayed so as to uniformly contact the surface of the pores of the porous body. Can be adopted.

Before bringing the plating solution into contact with the pore surface of the porous body, it is preferable to wash the pore surface of the porous body with an acidic solution and / or an alkaline solution. If the surface of the porous body to be dipped is washed with an acid or the like in advance, the adhesion with the metal can be enhanced.

The time for depositing the metal using the plating solution varies depending on the difference in the metal deposition method such as the dipping method and the filtration method, the thickness and material of the porous body, the type of the mixed plating solution, the deposition conditions, etc. 15 hours, preferably 5-10 hours.

The present invention is also a composite material of a porous body and a metal inside the pores of the porous body, wherein the metal inside the pores directly deposits the metal inside the pores. A metal matrix composite material is provided. The metal-based composite material is made of the above-mentioned manufacturing method, but is not limited to the one manufactured by the method, and may be manufactured by another method.

In the metal-based composite material having the above-mentioned structure, since the metal is directly deposited inside the pores of the porous body, there is no metal carbide such as TiC at the interface between the porous body and the metal, which is extremely high. It can have high thermal conductivity. Therefore, it can be suitably used as a heat sink for semiconductors and the like.

The above metal is a metal containing Ag.
High thermal conductivity can be obtained by using Ag as the filling metal or a metal containing Ag. Further, the metal may be an alloy of Ag and Cu, and other Al
You may include metals, such as. The metal species and the compounding ratio thereof can be appropriately set according to the required performance as the metal-based composite material.

The porous body is formed by compressing and fixing a large number of particles, and the particles constituting the porous body are composed of at least one of diamond, SiC, AlN, Si ₃ N ₄ and graphite. . In order to obtain a composite material having a high thermal conductivity, it is essential that the particles themselves constituting the porous body have a high thermal conductivity. Therefore, as the above particles, diamond, SiC, AlN, Si ₃ N ₄ , graphite or the like is used. Preferably
Especially, diamond is suitable for obtaining high thermal conductivity.

The above-mentioned porous body is a β type Si ₃ grown in a columnar shape.
Si ₃ N ₄ in which N ₄ particles are three-dimensionally randomly bonded
It is preferably a porous body. Since this porous body has high strength, a composite material having higher strength and higher thermal conductivity can be obtained by depositing a metal on the porous body to densify it. In this case, the average pore diameter is 0.01 to 3 μ
By using a porous Si ₃ N ₄ body having a size of about m, it is possible to obtain a composite material having an even higher thermal conductivity and an extremely high strength.

The average particle size of the particles constituting the above porous body is
Although not particularly limited, it is preferably 5 μm to 500 μm. This is because if it exceeds 500 μm, it becomes difficult to process the composite material, and if it is less than 5 μm, the surface area of the particles increases and the interfacial area between the particles and the metal increases, resulting in a large thermal resistance. The average particle size of the particles forming the porous body is 20 to 500 μm, preferably 30 to 300 μm when the composite material is used as a heat dissipation material.
More preferably, it is 30 to 150 μm.

The metal-based composite material used as a heat sink for semiconductors preferably has a relative density of 75% or more and a thermal conductivity of 400 W / mK or more, which is higher.
W / mK to 700 W / mK is preferable. The coefficient of thermal expansion is 6.0 ppm / K (6.0 × 10 ⁻⁶ / K) to 10.0.
ppm / K (10.0 × 10 ⁻⁶ / K) is preferable.

Further, the shape of the porous body can be various shapes such as disk shape, other flat plate shape, cube, rectangular parallelepiped, and other polyhedron depending on the use state as a product, workability, manufacturing method and the like. .

[0037]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a metal matrix composite material 1 of the present invention.
0 indicates that the metal-based composite material 10 includes a porous body 11 having a plurality of pores 11A, and the pores 11A of the porous body 11 are filled with a metal 12. The relative density is 99.1%, the thermal conductivity is 600 W / mK, and the thermal expansion coefficient is 9.8 ppm / K, which is particularly useful as a heat sink for semiconductors.

The metal 12 filled in the pores 11A is composed of the metal 12 in which the cations of the metal 12 are directly deposited on the surface of the porous body 11, and is Ag (silver). Further, the porous body 11 is formed by compressing and fixing a large number of particles 11B, and three-dimensional net-like pores 11A communicating with the surface openings of the porous body 11 are formed in the gaps between these particles 11B. As the particles, diamond particles having an average particle diameter of 300 μm are used for molding.

The first embodiment of the method for producing a metal-based composite material of the present invention will be described below. In the first embodiment,
The solution A containing Ag ions and the solution B containing a reducing agent are mixed, and the diamond porous body is immersed in the plating solution Q prepared by this mixing to deposit Ag in the pores of the porous body to form a metal. A matrix composite material is obtained.

Specifically, first, as shown in FIG. 2 (A), a porous body 11 formed by compressing and fixing a large number of diamond particles 11B having an average particle diameter of 300 μm is prepared. The porous body 11 has a large number of pores 11A due to a large number of particles 11B being in close contact with each other. The pores 11A are porous bodies 11
The plating solution is continuous with the openings on both sides of the
It is permeable to flow through the inside of A to the other side opening.
The porous body 11 has a disk shape with a diameter of 10 mm and a thickness of 100 μm, and the relative density is 50%. Further, as a pretreatment, the porous body 11 is sequentially immersed in nitric acid, an aqueous sodium hydroxide solution, and pure water to wash the surface of the porous body 11.

Next, in the container 15, solid silver nitrate is dissolved in distilled water. A strong base, 5% aqueous ammonia, is added to this to obtain solution A. When ammonia water is added, silver oxide (AgO), which is initially a brown precipitate (turbidity), is formed (reaction (1)). _{^{2Ag + + 2OH - → Ag 2}} O ↓ + H 2 O ··· reaction formula (1)

After that, when ammonia water is added until the precipitate just disappears, the precipitate becomes diammine silver ions and dissolves to become a colorless and transparent silver nitrate aqueous solution (reaction (2)). Reaction (1) and reaction (2) are performed at a low temperature of 5 ° C to 10 ° C. Ag ₂ O + 4NH ₃ + H ₂ O → 2 [Ag (NH ₃ ) ₂ ] ⁺ + 2OH ⁻ ·· Reaction formula (2)

While stirring this solution A, a reducing solution B containing formalin (37% or more formaldehyde aqueous solution) is added to obtain a plating solution Q. Figure 2
As shown in (B), the plating solution Q together with the container 15 is placed in the glass container 16, and then the porous body 11 is immersed in the plating solution Q. After that, the inside of the glass container 16 is evacuated by the rotary pump 17 to maintain the vacuum condition.

In this state, the temperature of the plating solution Q is set to 5
By heating to 0 ° C. and immersing the porous body 11 in the plating solution Q for 10 hours, the plating solution Q and the pores 1 of the porous body 11 are
1A is brought into contact with the surface of the porous body 11, and Ag is continuously deposited on the surface of the pores 11A of the porous body 11 by the reducing action of the reducing agent formalin, and Ag is densely filled in the pores 11A of the porous body 11. ing.

The Ag precipitation rate is controlled by the reaction formula
This can be performed by controlling the temperature of the silver nitrate aqueous solution obtained in (2). In the present embodiment, the heater 18
Is used to heat the temperature of the aqueous silver nitrate solution during the immersion of the porous body 11 to enhance the reducibility of Ag by formalin and increase the deposition rate of silver.

In this way, the solution A containing the ions of metal Ag and the solution B containing the reducing agent are mixed to obtain the plating solution Q, and the porous body 11 is immersed in the plating solution Q.
The plating solution Q flows into the pores 11A of the porous body 11 and Ag is deposited in the pores 11A by the reducing action of the reducing agent.
The holes 11A can be filled with Ag. Moreover, since the temperature of the plating solution Q is controlled and the immersion is performed under vacuum, Ag can be efficiently deposited in the pores 11A of the porous body 11.

The second embodiment of the method for producing a metal-based composite material of the present invention will be described below. In the second embodiment,
The plating solution is continuously filtered with a porous body, the plating solution and the surface of the pores of the porous body are continuously brought into contact with each other, and the pores are filled with a metal to obtain a metal-based composite material.

Specifically, as shown in FIG. 3, the porous body 21 is set in the cross flow filtration device 30 and filtration is performed. The porous body 21 is formed from diamond particles having an average particle size of 100 μm, and the diameter is 10 mm and the thickness is 1000 μm
Disk shape and the relative density is 66%. The solution A was the same as in the first embodiment, and the solution B was KBH ₄ to obtain a mixed solution.

The cross-flow filtration device 30 uses the plating solution Q.
A stock solution tank 31 for supplying a stock solution, a reserve tank 32 for storing a new plating solution to be supplied to the stock solution tank 31, a waste solution tank 33 for pouring a waste solution having a reduced concentration of metal ions and a reducing agent, and a porous body holder 34, The porous body holder 3
The heating furnace 40 for accommodating 4 is provided. Further, each of the tanks 31 to 33 and the porous body holder 34 are connected through a circulation path 35, and the plating solution is fed into the circulation path 35. The plating solution is supplied from the stock solution tank 31 to the porous body 21 via the water supply pump 36, the plating solution having a reduced concentration is flowed to the waste solution tank 33 via the drain pump 37, and a new plating solution is reserved. The stock solution is newly supplied from the tank 32 to the stock solution tank 31 via the auxiliary chamber 38. The stock solution tank 31 is configured to store the plating solution at a low temperature of about 5 ° C. to 10 ° C., and the porous body holder 3
By housing No. 4 in the heating furnace 40, the temperature of the plating solution during filtration can be kept at about 50 ° C. Instead of accommodating the porous body holder 34 in the heating furnace 40, a heater may be attached to heat and maintain the plating solution at the above temperature.

In the cross-flow filtration device 30, the porous body 21 is placed on the porous body holder 34 via the O-ring 39, and the plating solution is circulated in the direction of the arrow in the figure to obtain the porous body 2
The plating solution is continuously fed from one surface side (lower surface side) of the No. 1 toward the other surface side (upper surface side), and the plating solution is passed through the holes 21A of the porous body 21. The plating solution is reduced in the holes 21A to deposit Ag in the holes 21A.

Further, the plating solution having a reduced concentration is poured out to the waste solution tank 33, and a new plating solution is supplied from the spare tank 32 to the stock solution tank 31, whereby the porous body 21 is obtained.
The surface of the hole 21A is always in contact with a fresh plating solution. The transmembrane pressure difference, which is the pressure difference between the upper and lower sides of the porous body 21, was 0.1 MPa, and filtration was performed for 10 hours at a flow rate of 2 m / s.

As described above, by circulating and filtering the plating solution Q using the porous body 21, the plating solution Q can be sufficiently brought into contact with the pores 21A even when the thickness of the porous body 21 is large. The metal can be deposited near the center of the body 21. Moreover, since the fresh plating solution is continuously supplied, the metal can be always deposited efficiently.

Next, the partial dipping method of the third embodiment of the method for producing a metal-based composite material of the present invention will be described. Third
In the embodiment, the porous body is dipped into the plating solution by a predetermined thickness, and after filling the metal in the pores of the portion immersed in the plating solution, the remaining portion of the porous body is also sequentially plated in the plating solution. Repeatedly dipping in, the metal is filled into the pores by a predetermined thickness, and finally the metal is filled into the pores of the entire porous body,
A metal matrix composite material is obtained.

Specifically, as shown in FIGS. 4A to 4F, the porous body 41 hung on the wire w is immersed in the plating solution Q in the plating bath 50 step by step by a predetermined thickness. .
The porous body 41 is formed from diamond particles having an average particle size of 30 μm, is formed into a disk shape having a diameter of 10 mm and a thickness of 1000 μm, and has a relative density of 66%. The solution A was the same as in the first embodiment, and the solution B was KBH ₄ to obtain a mixed solution.

First, as shown in FIGS. 4 (A) to 4 (C),
The porous body 41 is immersed in the plating solution Q for 100 μm from the lower surface. The plating solution is poured into the holes 41A to deposit the metal (Ag) 42 on the immersed portion. Then, the plating solution in the plating solution tank 50 is replaced, and the porous body 41 is replaced with 100 μm in the new plating solution Q as shown in FIG. 4 (D).
The metal (Ag) 42 is deposited on the immersed portion. The immersion for each predetermined thickness is repeated stepwise with a fresh plating solution as shown in FIGS. 4 (E) and 4 (F).
FIG. 4F shows the final stage, in which the entire porous body 41 (thickness: 1000 μm) is immersed in the plating solution to deposit the metal (Ag) in the pores in the uppermost layer.

In this way, the porous body is gradually plated with the plating solution Q.
Even when the porous body 41 has a large thickness, the metal 42 can be densely deposited in a stepwise manner by immersing the porous body 41 in the pores 41A of the entire porous body 41, and the metal 42 can be completely removed.
Can be filled.

In addition to the above-mentioned embodiment, Cu, Al, or the like may be used as the metal to be deposited, or may be deposited as an alloy with Ag or the like. Further, as the porous body, it is possible to use a Si ₃ N ₄ porous body in which β-type Si ₃ N ₄ particles grown in a columnar shape are three-dimensionally randomly bonded, and the material, the constituent particle size, etc. may be appropriately changed. You can

Examples of the present invention will be described in detail below.

Example 1 Diamond powder having an average particle size of 300 μm was compressed and fixed, and a diameter of 10 mm and a thickness of 5
0 μm, 100 μm, 200 μm, 500 μm, 100
The thickness was changed to 0 μm (1 mm), and molding was performed to obtain a disk-shaped porous body having a relative density of 50%. «Reagents Preparation» reagent .... nitrate (AgNO ₃₎ 2g, 5% ammonia water (NH ₃₎ 5ml, 35% formalin 2 ml, 4m
50 ml of ol / l (20%) nitric acid (HNO ₃ ) and 50 ml of 20% sodium hydroxide solution (NaOH) were used. << Preparation of Solution >> Solution A: 2 g of silver nitrate was dissolved in 60 ml of distilled water. To this, 5% aqueous ammonia was added. At first, a brown precipitate was formed, but until it just disappeared,
Ammonia water was added, and finally water was added to make 100 ml. Solution B: 100 ml of distilled water and 2 ml of formalin were added. << Pretreatment of Porous Material >> The porous material is treated with 20% nitric acid for 5 minutes, and then 2
It was immersed in 0% sodium hydroxide for 5 minutes and finally in pure water for 5 minutes to remove dirt on the surface of the diamond particles. << Dense densification (deposition of metal) >> A plating solution was prepared by mixing solution A and solution B held at 5 ° C in equal amounts, and allowed to stand until the solution became transparent. (15 minutes) Each porous body was immersed in a plating solution, the plating solution was placed in a glass container together with the container, the glass container was evacuated by a rotary pump to reach 1 × 10 ⁻³ torr, and then the plating solution was added to 5
Heated to 0 ° C. The sample was evaluated by pulling it up after leaving it for 5 to 15 hours. The results are shown in Table 1 below.

[0060]

[Table 1]

Each item was measured by the following method. The same applies to Examples 2 to 4. Relative density: Calculate relative density of sample from weight change before and after densification Thermal conductivity: Measured by laser flash method Coefficient of thermal expansion: Measured by differential transformer type device (room temperature to 200
Average thermal expansion coefficient in ° C) X-ray diffraction: Identifies the precipitated phase

As shown in Table 1, after the plating treatment, metal A
g is deposited, and the thermal conductivity of the composite material is 100
It was higher than that of metallic Ag (420 W / mK) except for those of 0 μm. Moreover, when the thickness of the molded body was 100 μm or less, a composite material having a relative density of 99% or more was obtained. It was also confirmed that the effect was almost saturated when the plating time was 10 hours.

(Example 2) Average particle size is 10 to 550 μm
The diamond powder of 1 was molded into a diameter of 10 mm and a thickness of 100 μm to obtain a disk-shaped porous body having a relative density of 66%. Eight types of porous bodies having different diamond grain sizes were obtained. «Reagent preparation» reagent ... silver nitrate (AgNO ₃₎ 2g, copper sulfate 0.6
g, 5% ammonia water (NH ₃ ) 5 ml, NaBH ₄ or KBH ₄ 2 ml, 4 mol / l (20%) nitric acid (H
NO ₃ ) 50 ml, 20% sodium hydroxide solution (Na
OH) 50 ml was used. << Preparation of Solution >> Solution A: 2 g of silver nitrate and 0.6 g of copper sulfate in 60 ml of distilled water.
Melted. To this, 5% aqueous ammonia was added. At first, a brown precipitate was formed, but ammonia water was added until the precipitate just disappeared, and finally water was added to make 100 ml. Solution B: NaBH ₄ or KBH _{4 in} 100 ml of distilled water
2 ml was added. << Pretreatment of Porous Material >> The porous material is treated with 20% nitric acid for 5 minutes, and then 2
It was immersed in 0% sodium hydroxide for 5 minutes and finally in pure water for 5 minutes to remove dirt on the surface of the diamond particles. << Dense densification (deposition of metal) >> A plating solution was prepared by mixing solution A and solution B held at 5 ° C in equal amounts, and allowed to stand until the solution became transparent. (15 minutes) Each porous body was immersed in a plating solution, the plating solution was placed in a glass container together with the container, the glass container was evacuated by a rotary pump to reach 1 × 10 ⁻³ torr, and then the plating solution was added to 5
Heated to 0 ° C. The sample was evaluated by pulling it up after leaving it for 10 hours. The results are shown in Table 2 below.

[0064]

[Table 2]

As shown in Table 2, after the plating treatment, the metal A
A g-Cu alloy was deposited. When the diamond particle size was 20 μm or more, the thermal conductivity of each of the composite materials was higher than the thermal conductivity of metal Ag (420 W / mK).

Example 3 Diamond powder having an average particle size of 100 μm was molded into a diameter of 10 mm and a thickness of 1, 2, 5 mm to obtain a disk-shaped porous body having a relative density of 66%. «Reagent preparation» reagent ... silver nitrate (AgNO ₃₎ 200g, 5% aqueous ammonia _{(NH 3) 500ml, KBH 4} 200ml,
5000 mol of 4 mol / l (20%) nitric acid (HNO ₃ ),
5000 ml of 20% sodium hydroxide solution (NaOH)
Was used. << Preparation of Solution >> Solution A: 200 g of silver nitrate was dissolved in 6000 ml of distilled water. To this, 5% aqueous ammonia was added. At first, a brown precipitate was formed, but until it disappeared, ammonia water was added, and finally water was added to add 10
It was 000 ml. Solution B: 200 ml of KBH ₄ in 10,000 ml of distilled water
added. << Pretreatment of Porous Material >> The porous material is treated with 20% nitric acid for 5 minutes, and then 2
It was immersed in 0% sodium hydroxide for 5 minutes and finally in pure water for 5 minutes to remove dirt on the surface of the diamond particles. << Dense densification (deposition of metal) >> A plating solution was prepared by mixing solution A and solution B held at 5 ° C in equal amounts, and allowed to stand until the solution became transparent. (15 minutes) Each porous body and the plating solution were placed in the cross-flow filtration device shown in FIG. 3, and filtered for 10 hours at a transmembrane pressure difference of 0.1 MPa, a flow rate of 2 m / s and a temperature of 50 ° C. The sample after filtration was evaluated. The stock solution tank was set to a low temperature (5 to 10 ° C). In the present example, the temperature was raised by the flow of the plating solution in a cross flow to generate friction without using a heating furnace, and the filtration temperature was set to 50 ° C. In the filtration device, pressurization was applied at the discharge side inlet and negative pressure at the suction side was applied at the outlet side due to circulation by the pump. In addition, as a comparison, a sample in which only dipping was performed in the same manner as in Examples 1 and 2 without filtering was also produced and evaluated. The results are shown in Table 3 below.

[0067]

[Table 3]

As shown in Table 3, after the plating treatment, the metal A
g is deposited, and the thermal conductivity is that of metallic Ag (420 W
/ MK) or more. Further, when the filtration method was used, a composite material having a relative density of 99% or more was obtained even if the thickness of the molded body increased to 1000 μm or more.

Example 4 Diamond powder having an average particle diameter of 30 μm, SiC, AlN, Si ₃ N ₄ , and graphite powder were used to obtain a diameter of 1
It was molded into 0 mm × thickness of 1000 μm to obtain a disk-shaped porous body having a relative density of 66%. Further, porous Si ₃ N ₄ ceramics having a structure in which columnar Si ₃ N ₄ particles are randomly bonded in a three-dimensional manner (trade name Poacerum manufactured by Sumitomo Electric Industries, Ltd., average pore diameters 0.05 μm, 0.1 μm, 0.2 μm) was also used with the same shape. «Reagents Preparation» reagent .... nitrate (AgNO ₃₎ 2g, 5% ammonia water _{(NH 3) 5ml, KBH 4} 2ml, 4mol / l
50 ml of (20%) nitric acid (HNO ₃ ) and 50 ml of 20% sodium hydroxide solution (NaOH) were used. << Preparation of Solution >> Solution A: 2 g of silver nitrate was dissolved in 60 ml of distilled water. To this, 5% aqueous ammonia was added. At first, a brown precipitate was formed, but until it just disappeared,
Ammonia water was added, and finally water was added to make 100 ml. Solution B: 2 ml of KBH ₄ was added to 100 ml of distilled water. << Pretreatment of Porous Material >> The porous material is treated with 20% nitric acid for 5 minutes, and then 2
It was immersed in 0% sodium hydroxide for 5 minutes and finally in pure water for 5 minutes to remove stains on the surface of the porous body. << Dense densification (deposition of metal) >> A plating solution was prepared by mixing solution A and solution B held at 5 ° C in equal amounts, and allowed to stand until the solution became transparent. (15 minutes) By the method shown in FIG.
Immersion was performed only at a depth of m, the temperature was heated to 50 ° C., and the mixture was left for 10 hours. After that, a new plating solution is used to make the porous body 20
Immersion to 0 μm depth (newly 100 μm depth immersion),
It was left for 10 hours. By repeating this, the porous body was finally processed to a depth of 1000 μm. The sample after the plating treatment was evaluated. The results are shown in Table 4 below. The bending strength was evaluated by the three-point bending strength. Further, the plating treatment was performed under the vacuum condition of the degree of vacuum of 1 × 10 ⁻³ torr.

[0070]

[Table 4]

As shown in Table 4, by repeating the plating treatment, the compact could be densified even when the thickness of the compact was 1 mm (1000 μm). In addition, when the porous body is used as the porous body, the thermal conductivity is lowered, so that it is not suitable as a heat sink material for semiconductors, but diamond, SI
Since the strength is extremely higher than that of a porous body composed of C, AlN, Si ₃ N ₄ , and graphite, it is suitably used as a high-strength composite material.

[0072]

As is apparent from the above description, according to the method for producing a metal-based composite material of the present invention, a plating solution containing a solution A containing a metal as a cation and a solution B containing a reducing agent is mixed. A metal is deposited inside the pores of the porous body by the action of the reducing agent, and the metal is densely filled in the pores of the porous body by the deposition of the metal. Therefore, the adhesion between the porous body and the metal is good, and it is not necessary to use the metal in a molten state by heating, so that the metal matrix composite material having high thermal conductivity can be manufactured at extremely low cost.

By adjusting the temperature of the plating solution,
The metal deposition efficiency can be increased. Furthermore, depending on the thickness of the porous body, a method for depositing a metal on the surface of the porous body,
By appropriately changing to various methods such as filtration and dipping, a wide variety of metal-based composite materials can be obtained with high performance.

Further, in the metal-based composite material of the present invention, the metal filled in the pores is a metal in which the metal ions are directly deposited in the pores of the porous body, so that the metal is very dense. In addition to being a structure, there is no interface layer between the metal and the porous body. Therefore, very high thermal conductivity can be obtained. Therefore, it can be suitably used as a heat sink for semiconductors and the like.

According to the present invention, a heat sink material for a semiconductor having a high thermal conductivity and a thermal expansion coefficient close to that of a semiconductor element can be manufactured inexpensively without going through a high temperature process, and the performance of semiconductor lasers, microwave devices, various LSIs, etc. You can make the most of it.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a metal matrix composite material of the present invention.

2A and 2B are diagrams showing a method of immersing a porous body in a plating solution to deposit a metal in the pores.

FIG. 3 is a schematic diagram of a cross-flow filtration device.

4 (A) to (F) are diagrams showing a method of immersing a porous body in a plating solution with a predetermined thickness to gradually deposit metal in the pores of the entire porous body.

[Explanation of symbols]

10 Metal matrix composite materials 11 Porous body 11A hole 11B particles 12 metal

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4K020 AA22 AA24 AC05 BA02 BB30                 4K022 AA05 BA01 BA08 BA33 DA04                       DB01 DB04 DB06                 5F036 AA01 BB01 BD01 BD14 BD16

Claims (19)

[Claims] 1. A plating solution prepared by mixing a solution A containing a metal as a cation and a solution B containing a reducing agent is filled in a large number of pores of a porous body, and the metal is added by the reducing agent. A method for producing a metal-based composite material, which comprises depositing inside the pores to obtain a composite material comprising the porous body and a metal. 2. The pores of the porous body are composed of continuous three-dimensional mesh-like pores communicating with the surface openings of the porous body or a large number of independent pores communicating with the surface openings of the porous body,
The plating solution is permeable from the surface side to the inside of the pores, the relative density of the porous body is 40% to 70%, and the relative density after the metal is deposited inside the pores of the porous body is 88% to 99%. ．
The method for producing a metal-based composite material according to claim 1, wherein the content is 2%. 3. The solution A and the solution B are mixed in a low temperature region which is lower than the optimum temperature for the reducing action of the reducing agent, and the metal is deposited by reducing the plating solution with the reducing agent. The method for producing a metal-based composite material according to claim 1 or 2, wherein the deposition rate of the metal is controlled by performing it in a high temperature region heated to an optimum temperature for the action. 4. The Ag-based metal is used as the metal, and the porous body is formed by randomly and three-dimensionally compressing and fixing a large number of particles of at least one of diamond, SiC, AlN, Si ₃ N ₄ and graphite. The method for producing a metal-based composite material according to any one of claims 1 to 3, wherein the heat-dissipating material is formed and has a high thermal conductivity. 5. The solution A and the solution B are mixed under a temperature condition of 5 ° C. to 10 ° C., and the precipitation of the metal is 40 ° C.
The method for producing a metal-based composite material according to claim 4, which is performed under a temperature condition of 50 ° C. 6. The method for producing a metal-based composite material according to claim 4, wherein the solution A is an aqueous solution containing silver nitrate (AgNO ₃ ) and a strong base. 7. The method for producing a metal-based composite material according to claim 5, wherein the solution A contains Cu as an ion. 8. The solution B is formalin, NaB
H_Four, LiBH_Four, KBH _Four At least one of
It is a dissolved alcohol solution or aqueous solution.
Manufacturing of the metal matrix composite material according to claim 7.
Build method. 9. The porous body is dipped in the plating solution in a plating tank, the inside of the pores of the porous body is filled with the plating solution by vacuuming, and the metal is deposited inside the pores.
A method for manufacturing the metal-based composite material according to claim 8. 10. The porous body is gradually dipped in the plating solution by a predetermined thickness to gradually deposit the metal inside the pores of the porous body, and finally the metal is entirely deposited in the pores. The method for producing a metal-based composite material according to claim 9, wherein the metal is deposited. 11. The method according to claim 1, wherein the plating solution is circulated by a pump and continuously filtered by the porous body to deposit the metal inside the pores of the porous body. The method for producing a metal-based composite material according to item. 12. The pore surface of the porous body is washed with an acidic solution and / or an alkaline solution before the plating solution is brought into contact with the pore surface of the porous body. The method for producing the metal-based composite material according to any one of 1. 13. A composite material of a porous body and a metal inside pores of the porous body, wherein the metal is a metal-based composite material in which the metal is directly deposited inside the pores of the porous body. . 14. The method according to any one of claims 1 to 12.
14. The metal-based composite material according to claim 13, which is manufactured by the manufacturing method according to claim 13. 15. The metal is Ag alone or Ag and C.
On the other hand, the porous body is formed by compressing and fixing a large number of particles, and the particles are diamond, SiC, AlN, Si _{3 or the like.}
The metal matrix composite material according to claim 13 or 14, comprising at least one of N ₄ and graphite. 16. The β-type S grown in a columnar shape is the porous body.
i ₃ N ₄ Si ₃ in which three particles are randomly bonded in three dimensions
The metal-based composite material according to any one of claims 13 to 15, which is a N ₄ porous body. 17. The average particle size of particles constituting the porous body is 5 μm to 500 μm.
7. The metal matrix composite material according to item 6. 18. The metal-based composite material according to claim 13, which is used as a heat sink for semiconductors. 19. The metal-based composite material used as the heat sink for semiconductors has a relative density of 75% or more, a thermal conductivity of 400 W / mk to 700 W / mk, and a thermal expansion coefficient of 6.0.
The metal-based composite material according to claim 18, which has a ppm / K to 10.0 ppm / K.