JP5537012B2 - Heat sink material - Google Patents

Description

  The present invention relates to a heat sink material for configuring a heat sink that efficiently dissipates heat generated from, for example, an IC chip.

  In general, heat is a great enemy for IC chips, and the internal temperature must not exceed the maximum allowable junction temperature. In addition, since power consumption per operation area is large in a semiconductor device such as a power transistor or a semiconductor rectifier element, the amount of heat generated cannot be released only by the amount of heat released from the case (package) or lead of the semiconductor device. There is a risk that the internal temperature of the device will rise and cause thermal destruction.

  This phenomenon is the same in an IC chip equipped with a CPU. The amount of heat generated during operation increases as the clock frequency increases, and thermal design considering heat dissipation has become an important matter.

  In the thermal design considering the prevention of the thermal breakdown, element design and mounting design are performed in consideration of fixing a heat sink having a large heat radiation area to the case (package) of the IC chip.

  As a material for the heat sink, generally, a metal material such as copper or aluminum having a good thermal conductivity is used (for example, see Patent Documents 1 and 2).

JP-A-8-279579 (pages 2 to 4) JP 59-228742 A (pages 1 to 2)

  Recently, in an IC chip such as a CPU or a memory, the size of the IC chip itself is increased as the element is highly integrated and the element forming area is increased while the low power driving is aimed at low power consumption. There is a tendency. When the IC chip is increased in size, the stress generated by the difference in coefficient of thermal expansion between the semiconductor substrate (silicon substrate or GaAs substrate) and the heat sink increases, and there is a risk of the IC chip peeling phenomenon or mechanical destruction.

  In order to prevent this, it is possible to realize low-power driving of the IC chip and to improve the heat sink material. The low-power driving of the IC chip has been put to practical use at a level of 3.3 V or less, away from the conventionally used TTL level (5 V) as the power supply voltage.

  On the other hand, as a material for heat sinks, it is necessary not only to consider thermal conductivity, but also to select a material that has a thermal expansion coefficient substantially the same as that of silicon or GaAs, which is a semiconductor substrate, and that has high thermal conductivity. ing.

  Regarding the improvement of the heat sink material, there are various reports, such as an example using aluminum nitride (AlN) and an example using Cu (copper) -W (tungsten). AlN is excellent in the balance between thermal conductivity and thermal expansibility, and is particularly suitable for a heat sink material of a semiconductor device using a silicon substrate as a semiconductor substrate because it almost matches the thermal expansion coefficient of Si.

  Cu-W is a composite material having both low thermal expansion of W and high thermal conductivity of Cu, and is easy to machine, so it is suitable as a constituent material of a heat sink having a complicated shape. .

  Further, as other examples, a ceramic base material containing SiC as a main component containing metal Cu in a proportion of 20 vol% to 40 vol% (patent document 1), or a powder sintered porous material made of an inorganic substance A body impregnated with 5 vol% to 30 wt% of Cu (Patent Document 2) has been proposed.

  Since the heat sink material according to Patent Document 1 is powder molding in which a green compact of SiC and metal Cu is molded to produce a heat sink, the thermal expansion coefficient and thermal conductivity are theoretical values to the last. There is a problem that the balance between the thermal expansion coefficient and the thermal conductivity required for an actual electronic component or the like cannot be obtained.

  The heat sink material according to Patent Document 2 has a low ratio of Cu impregnated into a powder sintered porous body made of an inorganic substance, and there is a possibility that a limit may arise in increasing the thermal conductivity.

  The heat sink material described above is suitable as a composite material having high thermal conductivity, but has a problem that desired mechanical strength cannot be obtained. This is because, since the mechanical strength of a carbon material such as a ceramic material as a base is relatively low, it is difficult to secure the impregnation pressure for metal impregnation with respect to the carbon material, so that residual pores are easily generated in the composite material. Because.

  The residual pores cause a decrease in thermal conductivity in the composite material, generation of voids at the interface between the solder and the composite material in the solder plating process of the composite material, and a decrease in wettability between the solder and the composite material.

  In recent years, it has become possible to achieve high thermal conductivity in a composite material using only a carbon material. Therefore, it is necessary to produce a composite material having high thermal conductivity by impregnating the pores of the carbon material with a metal. Sex is declining. In this case, the role of the metal is to efficiently impregnate the pores in the carbon material to reduce residual pores and improve the mechanical strength of the heat sink material. Furthermore, it has become an urgent issue to prevent moisture and the like from permeating into the residual pores generated in the solder plating process and to prevent voids, blisters, and peeling associated therewith.

  The present invention has been made in consideration of such problems, and in a heat sink material obtained by impregnating metal in the pores of a carbon material, the residual pores of the heat sink material generated during metal impregnation are reduced, and the heat sink An object of the present invention is to provide a heat sink material having high mechanical strength by improving wettability between the material and solder plating covering the surface of the heat sink material.

  The heat sink material according to the present invention is characterized by being composed of carbon or an allotrope thereof and a metal having a property of solidification expansion or a metal having a property of suppressing solidification shrinkage. By impregnating the heat sink material with a metal whose volume expands in the vicinity of the solidification temperature or a metal with a small volume shrinkage, it is possible to reduce the amount of metal shrinkage that occurs during the cooling process from the solidification temperature to room temperature. . Therefore, generation of residual pores in the heat sink material can be suppressed.

  Bi, Sb, Ga, graphite cast iron, and alloys containing these metals are selected as metals that exhibit the above-described effects. These are metals having the property of suppressing solidification expansion or solidification shrinkage.

  Further, when a metal having a low solidification temperature is selected as the metal, the amount of shrinkage of the metal cooled from the solidification temperature to room temperature can be reduced. In this case, the heat sink material is incorporated into an actual electronic component or the like, soldering work is performed, and the heat sink material is reheated. Therefore, it is desirable to select a metal that does not melt even with the heat of the soldering operation, that is, a metal having a solidification temperature of 300 ° C. or higher.

  Moreover, you may select the metal which segregation does not generate | occur | produce as said metal easily. This is because, in the case of a metal having a low melting point, when seen from the phase diagram, the primary crystal of the metal is easily segregated and the metal may be melted in a temperature range of 200 ° C. or lower.

  Further, as the metal, it is preferable to use a metal having a property of good wettability with the heat sink material. In the case of a metal with good wettability, the pores of the carbon material can be easily impregnated even at a low impregnation pressure.

  Moreover, it is preferable that it is 300 W / mK or more as an average of the three axial directions to which a heat sink material orthogonally crosses, or the thermal conductivity in any axial direction.

  On the other hand, it is preferable that the thermal conductivity of carbon or the allotrope thereof used as the base material of the heat sink material is 150 W / mK or more. In the absence of pores, 200 W / mK or more, more preferably 250 W / mK or more, and even more preferably 300 W / mK or more is desirable. By selecting such carbon or its allotrope, it is possible to stably supply a heat sink material having a high thermal conductivity regardless of the type of metal.

  The allotrope is preferably graphite or diamond. This is because these allotropes have high thermal conductivity.

  And the heat sink material comprised from the above-mentioned material is comprised by impregnating the said metal in the porous sintered compact obtained by baking and networking the said carbon or its allotrope. In this case, the porosity of the porous sintered body is 10 vol% to 50 vol%, and the average pore diameter is 0.1 μm to 200 μm.

  The volume ratio of the carbon or the allotrope constituting the heat sink material and the metal is in the range of 50 vol% to 90 vol% for the carbon or the allotrope, and 50 vol% to 10 vol% for the metal. It becomes.

  Further, in order to realize a heat sink material having high mechanical strength, which is the object of the present invention, an additive that reduces the closed porosity when the carbon or its allotrope is fired to the carbon or its allotrope It is desirable to add. In this case, SiC and / or Si is selected as an additive for reducing the closed porosity. By the addition of the additive, it is possible to reduce residual pores generated at the time of firing carbon or an allotrope thereof. In particular, when these additives are impregnated into a preform composed of carbon or an allotrope thereof, the impregnation rate of the metal is improved and the residual pores can be efficiently reduced.

  In addition to the metal, one or more elements selected from Te, Bi, Pb, Sn, Se, Li, Sb, Tl, and Cd are added to improve the wettability of the heat sink material interface. Is desirable. By adding these elements, wettability with carbon or an allotrope thereof is improved, and impregnation at low pressure is possible. Also, the bondability at the interface is improved. Further, the wettability between the heat sink material and the solder plating on the surface of the heat sink material is improved, and the generation of voids at the interface can be reduced.

  Furthermore, if a carbide layer is formed on the surface of the carbon or its allotrope, the bonding strength with the impregnated metal is improved through the carbide layer, and the heat conduction and the strength of the composite material can be improved. In addition, the hardness of the carbide itself contributes to strength improvement. Furthermore, in addition to improving the wettability at the interface between the heat sink material and the solder plating of the heat sink material, it is possible to impregnate the metal at a low pressure and to impregnate fine pores.

  The formation of the carbide layer is based on at least a reaction between the carbon or an allotrope thereof and an additive element. Examples of the additive element selected include Nb, Cr, Zr, Be, V, Mo, Al, At least one element is selected from Ta, Mn, Si, Fe, Co, Ni, Mg, Ca, W, Ti, B, and Misch metal.

  Further, as the heat sink material, in addition to the heat sink material composed of the porous sintered body and the metal, water or a binder is mixed with the carbon or its allotrope powder and molded under a predetermined pressure. This can also be realized by impregnating the preformed body or the fired molded body with the metal. Moreover, the heat sink material comprised by mixing the said carbon or its allotrope powder and the said metal powder, and shape | molding under a predetermined pressure may be sufficient. Furthermore, a heat sink material configured by mixing the carbon or its allotrope powder in a liquid state in which the metal is dissolved or in a solid-liquid coexisting state and casting it may be used. Moreover, the heat sink material comprised by impregnating the said metal in the powder of the said carbon or its allotrope may be sufficient.

  The average powder particle size of the carbon or its allotrope powder constituting these heat sink materials is 1 μm to 500 μm, and the direction in which one particle (powder) constituting the powder takes the minimum length and the maximum The average length ratio is 1: 5 or less in the direction of taking the length.

  Further, the heat sink material may be configured by mixing the pulverized cutting material of the carbon or its allotrope and the metal powder, and molding the mixture at a predetermined temperature and a predetermined pressure.

  In the heat sink material thus produced, the volume ratio of carbon or its allotrope and the metal is preferably in the range of 20 vol% to 80 vol% for the carbon or its allotrope and 80 vol% to 20 vol% for the metal. .

  Further, it is desirable that an additive element that reinforces the bonding of the metal when formed is added to these heat sink materials. In this case, the additive element is preferably selected from Bi, Te, Sn, Pb, Se, Li, Sb, Tl, and Cd. In this case, the additive element is preferably selected from elements such as Nb, Zr, Cr, and Be that are difficult to dissolve in copper. By adding an additive element that dissolves only 0.5 wt% or less in copper, the thermal conductivity does not decrease and a good heat sink material can be obtained.

  Moreover, it is preferable to add an additive element that strengthens the bond between carbon or an allotrope thereof and a metal during the molding. In this case, the additive element is selected from Nb, Zr, Cr, Be, V, Mo, Al, Ta, Mn, Si, Fe, Co, Ni, Mg, Ca, W, Ti, B, and Misch metal. It is desirable.

  Moreover, you may make it add the additional element which enables the reheating after shaping | molding to the said carbon or its allotrope. In this case, the formation of the heat sink material is preferably based on a reaction between at least the carbon or its allotrope and an additive element. The additive element is selected from Nb, Zr, Cr, Be, V, Mo, Al, Ta, Mn, Si, Fe, Co, Ni, Mg, Ca, W, Ti, B, and Misch metal. One or more are preferable.

  Further, it is more preferable to form carbides by additive elements on the surface of the carbon or the allotrope constituting the above heat sink material. By forming the carbide, the bonding strength with the impregnated metal is improved through the carbide layer, and the heat conduction and the strength of the composite material are also improved. In addition, the hardness of the carbide itself contributes to strength improvement. As a result, the metal can be impregnated at a low pressure, and the residual porosity that enables the impregnation of fine pores can be reduced. In order to achieve such an effect, the additive elements are Nb, Zr, Cr, Be, V, Mo, Al, Ta, Mn, Si, Fe, Co, Ni, Mg, Ca, W, Ti, B, It is desirable to select from one or more types of misch metal.

  Finally, the residual porosity of the heat sink material produced by the above-described means can be reduced to 5% or less.

  As described above, according to the heat sink material according to the present invention, the characteristic is suitable for the balance between the thermal expansion coefficient and the thermal conductivity required for an actual electronic component (including a semiconductor device) and has a low porosity. Can be obtained. Therefore, a high-quality heat sink material having high mechanical strength can be realized.

  Embodiments of the heat sink material according to the present invention will be described below with reference to FIGS.

  As shown in FIG. 1, the heat sink material 10 </ b> A according to the first embodiment is configured by impregnating a porous sintered body 12 obtained by firing and networking carbon or an allotrope thereof with a metal 14. ing.

  In this case, the carbon or its allotrope has a thermal conductivity of 150 W / mK or more, preferably 200 W / mK or more (estimated value in the absence of pores), more preferably 250 W / mK or more (in the absence of pores). (Estimated value), more desirably 300 W / mK or more (estimated value in the absence of pores) is preferably used.

  In the first embodiment, a heat sink material 10A is used in which copper is impregnated in the open pores of the porous sintered body 12 made of graphite having a thermal conductivity of 150 W / mK or more. As the metal 14 to be impregnated, a metal having a property of solidification expansion or a metal having a property of suppressing solidification shrinkage is preferably used. In addition to Bi, a metal selected from Pb, graphite cast iron, or the metal An alloy consisting of can be used.

  In addition, the volume ratio between the porous sintered body 12 and the metal 14 is in the range of 50 vol% to 90 vol% for the porous sintered body 12 and 10 vol% to 50 vol% for the metal 14. Thereby, it is possible to obtain a heat sink material 10A having an average of three orthogonal directions perpendicular to each other or a thermal conductivity of 300 W / mK or more and a residual porosity of 5% or less.

  The porosity of the porous sintered body 12 is preferably 10 vol% to 50 vol%. When the porosity is 10 vol% or less, it is impossible to obtain an average of three orthogonal directions or a thermal conductivity of 300 W / mK (room temperature) in any axial direction. When the porosity exceeds 50 vol%, the porous sintered body 12 This is because the strength of the steel is reduced, and the porosity cannot be suppressed to 5% or less.

  The average open pore size (pore size) of the porous sintered body 12 is preferably 0.1 μm to 200 μm. When the pore diameter is less than 0.1 μm, it becomes difficult to impregnate the open pores with the metal 14 and the thermal conductivity is lowered. On the other hand, when the pore diameter exceeds 200 μm, the strength of the porous sintered body 12 is lowered and the coefficient of thermal expansion cannot be kept low.

  As a distribution (pore distribution) regarding the average open pores of the porous sintered body 12, it is preferable that 90 vol% or more is distributed in a range of 0.5 μm to 50 μm. When the pores of 0.5 μm to 50 μm are not distributed by 90 vol% or more, open pores not impregnated with the metal 14 increase, and the thermal conductivity may be lowered.

  Further, the closed porosity of the heat sink material 10A obtained by impregnating the porous sintered body 12 with the metal 14 is preferably 5 vol% or less. It is because thermal conductivity may fall when it exceeds 5 vol%.

  Note that an automatic porosimeter (trade name “Autopore 9200”) manufactured by Shimadzu Corporation was used to measure the porosity, pore diameter, and pore distribution.

  In the heat sink material 10A according to the first embodiment, it is preferable that an additive for reducing the closed porosity when the graphite is baked is added to the graphite. Examples of the additive include SiC and / or Si. Thereby, closed pores (closed pores) during firing can be reduced, and the impregnation ratio of the metal 14 to the porous sintered body 12 can be improved.

  Moreover, it is preferable to add one or more selected from Te, Bi, Pb, Sn, Se, Sb, Li, Tl, and Cd to the metal 14 impregnated in the porous sintered body 12. Thereby, the wettability of the interface between the porous sintered body 12 and the metal 14 is improved, and the metal 14 can easily enter the open pores of the porous sintered body 12.

  On the other hand, the metal 14 impregnated in the porous sintered body 12 includes Nb, Cr, Zr, Be, V, Mo, Al, Ta, Mn, Si, Fe, Co, Ni, Mg, Ca, W, Mo, It is preferable to add one or more selected from Ti, B, and Misch metal. As a result, the reactivity between graphite and the metal 14 is improved, and the graphite and the metal 14 are easily aligned and adhered in the open pores, and the closed porosity can be reduced.

  Next, several methods for manufacturing the heat sink material 10A according to the first embodiment will be described with reference to FIGS.

  Both the first and second manufacturing methods for manufacturing the heat sink material 10A according to the first embodiment include a firing step of fabricating the porous sintered body 12 by firing and networking graphite. And an impregnation step of impregnating the porous sintered body 12 with the metal 14.

  The first manufacturing method is performed by using a high-pressure vessel 30 as specifically shown in FIGS. 2A and 2B. The high-pressure vessel 30 is provided with a rotation shaft 38 at a substantially central portion of both side plates 34 and 36 in a rectangular tube-shaped housing 32, and the housing 32 itself can rotate about the rotation shaft 38. ing.

  A fireproof container 40 and a heater 42 for heating the fireproof container 40 are provided in the housing 32. The refractory container 40 has a rectangular tube shape having a hollow portion 44, and an opening 46 communicating with the hollow portion 44 is provided at a central portion in the height direction on one side surface. Among the hollow portions 44, one hollow portion (hereinafter referred to as the first chamber 44 a) centering on the opening 46 accommodates a lump of the metal 14 that is an impregnation material or a molten metal of the metal 14. ing.

  The other hollow portion (hereinafter referred to as the second chamber 44b) is configured to be attached with a plurality of porous sintered bodies 12 that are impregnated samples, and even if the second chamber 44b is located above, the porous portion is porous. A support mechanism for the porous sintered body 12 is provided so that the sintered material 12 does not fall. The heater 42 has a structure that is not broken even under a high pressure of 300 MPa.

  Further, the high-pressure vessel 30 is provided with an intake pipe 48 for evacuation, and an introduction pipe 50 and a lead-out pipe 52 for a gas for applying a high pressure and a cooling gas.

  Next, a first manufacturing method using the high-pressure vessel 30 will be described with reference to FIG.

  First, in step S1, a porous sintered body 12 made of graphite is produced through a step of forming graphite into a rod shape, a step of impregnating pitch (a kind of coal tar), and a step of heating and firing.

  In order to form graphite into a rod shape, pitch is mixed with graphite powder and extrusion molding is performed in an atmosphere at about 150 ° C. to obtain a rod-like (φ100 to φ600, length of about 3000 mm) graphite. Graphite in this state has many pores and low thermal conductivity.

  Next, vacuum deaeration is performed to reduce graphite pores, and pitch is impregnated in the vacuum. And the process of baking at about 1000 degreeC and impregnating a pitch is repeated about 3 times.

  Then, the graphite is heated and fired in a furnace at about 3000 ° C. in order to improve the thermal conductivity. At this time, in order to prevent the graphite from burning, the furnace is covered with carbon powder, and the graphite itself is also covered with carbon powder. Further, the step of heating the graphite may be performed by heating and firing by directly energizing the graphite.

  By doing so, a porous sintered body 12 can be obtained, but it is desirable to further perform preliminary processing depending on the shape of the final product.

  Thereafter, in step S2, the high pressure vessel 30 is set in an initial state, and the first chamber 44a of the refractory vessel 40 provided in the high pressure vessel 30 is positioned below.

  Thereafter, the mass of the porous sintered body 12 and the metal 14 is put in the refractory container 40 of the high-pressure vessel 30, the mass of the metal 14 is placed in the first chamber 44 a of the refractory container 40, and the porous sintered body 12 is Set in the second chamber 44b (step S3). At this time, it is preferable to preheat the porous sintered body 12 in advance. In order to perform preheating, the porous sintered body 12 is stored in a carbon case or covered with a heat insulating material, and preheated in a state where the porous sintered body 12 is covered with a heat insulating material. The state is set in the second chamber 44b as described above.

  Thereafter, after sealing the high-pressure vessel 30 (and the refractory vessel 40), the inside of the high-pressure vessel 30 is evacuated through the intake pipe 48 to bring the inside of the high-pressure vessel 30 into a negative pressure state (step S4).

  Thereafter, the heater 42 is energized to heat and dissolve the metal 14 in the first chamber 44a (step S5). In the following description, the heat-dissolved metal 14 is also referred to as a molten metal 14 for convenience.

  Thereafter, when the molten metal 14 in the first chamber 44a reaches a predetermined temperature, the high-pressure vessel 30 is turned 180 ° (step S6). By this turning operation, the first chamber 44a is positioned upward, so that the molten metal 14 in the first chamber 44a falls into the second chamber 44b positioned below due to its own weight, and at this stage, the molten metal 14 In this state, the porous sintered body 12 is impregnated.

  Thereafter, the impregnation gas is introduced into the high-pressure vessel 30 through the gas introduction pipe 50, and the inside of the high-pressure vessel 30 is pressurized (step S7). By this pressure treatment, the molten metal 14 is impregnated in the open pores of the porous sintered body 12.

  Immediately after the impregnation step, the process proceeds to the cooling step. In this cooling process, first, the high-pressure vessel 30 is rotated 180 ° again (step S8). By this turning operation, the first chamber 44a is positioned below, so that the molten metal 14 in the second chamber 44b falls again into the first chamber 44a.

  Since a part of the molten metal 14 is impregnated in the open pores of the porous sintered body 12 by the pressurizing process (impregnation process) in step S7, it falls into the first chamber 44a located below. The molten metal 14 is a residual molten metal that has not been impregnated into the porous sintered body 12. When the remaining molten metal falls into the first chamber 44a, the porous sintered body 12 impregnated with the molten metal 14 remains in the second chamber 44b.

  Thereafter, the impregnation gas in the high-pressure vessel 30 is exhausted through the gas outlet tube 52, and at the same time, the cooling gas is introduced into the high-pressure vessel 30 through the gas introduction tube 50 (step S9). By exhausting the impregnation gas and introducing the cooling gas, the cooling gas circulates uniformly in the high-pressure vessel 30 and the high-pressure vessel 30 is rapidly cooled. Due to this rapid cooling, the molten metal 14 impregnated in the porous sintered body 12 rapidly solidifies into a lump of metal 14 and the volume expands, so that the impregnated metal 14 is porous sintered body. 12 is firmly held.

  As another cooling process, as shown in a dashed-dotted line frame in FIG. 3, the porous sintered body 12 impregnated with the high-pressure vessel 30 or the molten metal 14 at the stage when the process in the step S8 is completed. Is transported to the cooling zone and brought into contact with a chiller installed in the cooling zone (see step S10).

  The porous sintered body 12 is rapidly cooled by the contact with the cooling metal. In this cooling process, cooling gas may be sprayed on the porous sintered body 12 or cooling metal may be cooled with water, and cooling is particularly preferred in view of the feeder effect.

  As described above, by performing each step of the first manufacturing method, the impregnation treatment of the metal 14 into the porous sintered body 12 with graphite can be easily performed. A heat sink that can improve the impregnation ratio of the metal 14, has an average of three orthogonal axes, or a thermal conductivity of 300 W / mK or more in any axial direction, and a residual porosity of 5% or less. The material 10A can be obtained.

  Further, even when SiC is employed for the porous sintered body 12 to be described later, the closed porosity from room temperature to 200 ° C. is 5% or less, and the average of three orthogonal directions or heat conduction in any axial direction A heat sink material 10A having a rate of 300 W / mK or more can be easily obtained.

In step S5, when the heater 42 is energized and the metal 14 in the first chamber 44a is heated and melted, the predetermined temperature (heating temperature) at which the process proceeds to step S6 is 30 ° C to 250 ° C higher than the melting point of the metal 14 The temperature is preferably 50 to 200 ° C. higher than the melting point. In this case, it is preferable to keep the inside of the high-pressure vessel 30 in a vacuum of 1 × 10 ⁻³ Torr or less.

  In step S7, the pressure applied to the high-pressure vessel 30 by introducing the impregnation gas into the high-pressure vessel 30 is set to 0.98 MPa or more and 202 MPa or less. In this case, the pressure is preferably 4.9 MPa or more and 202 MPa or less, more preferably 9.8 MPa or more and 202 MPa or less.

  A higher pressure is preferable from the viewpoint of improving the impregnation rate and cooling capacity. However, if the pressure is too high, the graphite is liable to break, and the cost of the equipment that can withstand high pressure increases. Therefore, the pressure is selected in consideration of these factors.

  Further, the pressure application time to the high-pressure vessel 30 is preferably 1 second to 60 seconds, and more preferably 1 second to 30 seconds.

  As described above, the pores of the porous sintered body 12 desirably have an average diameter of 0.1 μm to 200 μm and a porosity of 10 vol% to 50 vol%.

  However, when SiC is used for the porous sintered body 12 described later, it is desirable that 90% or more of those having an average diameter of 5 μm to 50 μm are present and the porosity is 20 vol% to 70 vol%.

  On the other hand, the cooling rate in the cooling step is preferably −400 ° C./hour or more, and more preferably −800 ° C./hour or more in the period from the temperature during impregnation to 800 ° C.

  In step S7, the pressure applied to the high-pressure vessel 30 is a pressure necessary for completely impregnating the metal 14 into the open pores of the porous sintered body 12. In this case, if open pores that are not impregnated with the metal 14 remain in the porous sintered body 12, the thermal conductivity is remarkably inhibited, and thus it is necessary to apply a high pressure.

  This pressure can be roughly estimated by the Washburn equation, but the smaller the pore diameter, the greater the force required. According to this equation, a pressure of 39.2 MPa for 0.1 μmφ, 3.92 MPa for 1.0 μmφ, and 0.392 MPa for 10 μmφ is appropriate. However, in reality, a material having an average pore diameter of 0.1 μmφ has pores having a diameter of 0.01 μmφ or less, and thus a larger pressure is required. Specifically, a pressure of 392 MPa is required for 0.01 μmφ.

  In addition, since the preferable example of the additive element to graphite and the additive element to the metal 14 was already described, the description is abbreviate | omitted here.

  Next, some modifications of the first manufacturing method will be described with reference to FIGS.

  In the first modified example, as shown in FIG. 4, first, graphite is fired to produce a porous sintered body 12 made of graphite (step S101). With the high-pressure vessel 30 in the initial state, the first chamber 44a of the refractory vessel 40 provided in the high-pressure vessel 30 is positioned below (step S102).

  Thereafter, the porous sintered body 12 is set in the second chamber 44b, and the previously melted metal (molten metal) 14 is poured into the first chamber 44a (step S103).

  Thereafter, when the molten metal 14 in the first chamber 44a has reached a predetermined temperature, the high-pressure vessel 30 is turned 180 ° (step S104). By this turning operation, the molten metal 14 in the first chamber 44a falls into the second chamber 44b located below, and at this stage, the molten metal 14 is impregnated with the porous sintered body 12.

  Thereafter, the impregnation gas is introduced into the high-pressure vessel 30 through the gas introduction pipe 50, and the inside of the high-pressure vessel 30 is pressurized (step S105). By this pressure treatment, the molten metal 14 is impregnated in the open pores of the porous sintered body 12.

  Next, a second modification will be described with reference to FIG. In the impregnation step according to the second modified example, the high-pressure vessel 30 in which a partition plate (not shown) made of a porous ceramic material is provided in the inner central portion of the refractory vessel 40 installed in the high-pressure vessel 30. Is used. The inside of the refractory container 40 is partitioned into a first chamber 44a and a second chamber 44b by the partition plate.

  As the partition plate, it is desirable to use a porous ceramic material having a porosity of 40 vol% to 90 vol% and a pore diameter of 0.5 mm to 3.0 mm, more preferably a porosity of 70 vol% to 85 vol%. It is desirable to use a porous ceramic material having a pore diameter of 1.0 mm to 2.0 mm.

  And in this 2nd modification, as shown in FIG. 5, first, graphite is baked and the porous sintered compact 12 by graphite is produced (step S201). With the high-pressure vessel 30 in the initial state, the first chamber 44a of the refractory vessel 40 provided in the high-pressure vessel 30 is positioned downward and the second chamber 44b is positioned upward (step S202).

  After that, the mass of the porous sintered body 12 and the metal 14 is put in the refractory container 40 of the high-pressure vessel 30, and the mass of the metal 14 is disposed in the second chamber 44b located above, so that the porous sintered body 12 is The first chamber 44a located below is set (step S203).

  Thereafter, after sealing the high-pressure vessel 30 (and the refractory vessel 40), the inside of the high-pressure vessel 30 is evacuated through the intake pipe 48 to bring the inside of the high-pressure vessel 30 into a negative pressure state (step S204).

  Thereafter, the heater 42 is energized to heat and dissolve the metal 14 in the second chamber 44b (step S205). When the molten metal 14 reaches a predetermined temperature, an impregnation gas is introduced into the high-pressure vessel 30 through the gas introduction pipe 50, and the inside of the high-pressure vessel 30 is pressurized (step S206). By this pressurizing treatment, the molten metal 14 in the second chamber 44b located above passes through the partition plate and is impregnated in the open pores of the porous sintered body 12 in the first chamber 44a located below. Will be.

  Next, the second manufacturing method will be described with reference to FIGS. In this second manufacturing method, as shown in FIG. 6, a furnace 60 for firing graphite to produce the porous sintered body 12 and a porous sintered body 12 as shown in FIG. A press 62 for impregnating 14 is used.

  As shown in FIG. 6, the furnace 60 is used to graphitize graphite, and heats the space 72 in which the case 70 can be accommodated and the case 70 accommodated in the space 72. A heater 74 is provided. The case 70 is made of a material such as graphite, ceramics, and Cerapaper (a heat insulating material made of ceramics such as alumina). And this case 70 accommodates graphite.

  As shown in FIG. 7, the press machine 62 includes a die 82 having a concave portion 80 with an upper opening, and a punch 84 that can be inserted into the concave portion 80 and press-down the contents in the concave portion 80. .

  Next, a second manufacturing method using the furnace 60 and the press machine 62 will be described with reference to FIGS.

  First, graphite is put in the case 70, and the case 70 is accommodated in the furnace 60 (step S301). The atmosphere in the furnace 60 is heated to burn the graphite to produce the porous sintered body 12 (step S302).

  In this step, the porous sintered body 12 may be produced by heating to about 3000 ° C. by passing an electric current through the graphite.

  Thereafter, the porous sintered body 12 and the case 70 are taken out from the furnace 60, and the porous sintered body 12 and the case 70 are accommodated in the recess 80 of the press machine 62 (step S303).

  Next, after the molten metal 86 of the metal 14 is poured into the case 70 (step S304), the punch 84 is inserted into the recess 80, and the molten metal 86 in the case 70 is pressed down and pressed (step S305). By the pressing process of the punch 84, the molten metal 86 of the metal 14 is impregnated in the open pores of the porous sintered body 12.

  In the second manufacturing method described above, the pressure at the time of press-fitting with the punch 84 is preferably 1.01 MPa to 202 MPa (10 atm to 2000 atm). Further, as shown in FIG. 7, gas vent holes 88 and 90 for venting the gas remaining in the porous sintered body 12 and a gap portion for venting the gas are formed at the bottom of the case 70 and the bottom of the mold 82. You may make it form. In this case, when the punch 84 is press-fitted, the gas remaining in the porous sintered body 12 escapes through the vent holes 88 and 90, so that the molten metal 86 is smoothly impregnated into the open pores.

  As described above, by performing each step of the second manufacturing method, the impregnation treatment of the metal 14 into the porous sintered body 12 with graphite can be easily performed. A heat sink material that can improve the impregnation rate of the metal 14, has an average of three orthogonal axes, or a thermal conductivity of 300 W / mK or more in any axial direction, and a porosity of 5% or less. 10A can be easily obtained.

  Instead of the furnace 60 described above, a furnace utilizing preheating may be used. In this case, the porous sintered body 12 made of a previously compacted material or graphite is preheated. This process makes it easier for the metal 14 to impregnate graphite (or SiC described later) networked. The preheating temperature is preferably preheated to a temperature similar to that of the molten metal 86. Specifically, if the molten metal 86 is about 1200 ° C, the preheating temperature of graphite is desirably 1000 ° C to 1400 ° C.

  Next, one experimental example is shown. In this experimental example, by using the second manufacturing method, the type of metal 14 impregnated into one type of carbon (graphite) and the type of additive element are changed, and the difference in density, the difference in thermal conductivity, It shows the effects of additive elements on the difference in thermal expansion coefficient and the difference in porosity after metal impregnation. The results of this experimental example are shown in FIGS.

  FIG. 9 shows a cross-sectional view in the IV-IV line direction of the heat sink material 10A shown in FIG. 1 produced by the second manufacturing method. About the difference in the density, the impregnation portion of the heat sink material 10A was divided into six impregnation portions 10a to 10f, and the density in the six divisions was measured.

  10 to 13 show the density of the heat sink material 10A at the impregnation locations 10a to 10f. Here, there are six types of heat sink materials 10A prepared by adding the above-described additive elements to the metal 14 (75Sb / 25Cu, 70Sb / 30Te, 60Sb / 40Sn, 15Ni-85Bi, 85Sb-15Bi, 70Sb-1Zr-29Sn). The three types of heat sink materials 10A (70Ni-30Si, 75Al-25Si, 50Sn-50Cu) other than the six types are heat sink materials configured based on the prior art. The material (NS3-21) is graphite which is the base material of the heat sink material 10A. It can be seen that there is almost no variation in the density of the heat sink material 10A by adding the additive element to the metal 14. That is, it indicates that the impregnation portions 10a to 10f are impregnated with the same amount of metal 14, and suggests that the porosity is also the same.

  14 to 20 show differences in thermal conductivity, thermal expansion coefficient, and metal impregnation in the experimental example and four types of heat sink materials 10A (95Sb-5Cu, 95Sb-5Bi, 95Sb-5Sn, 95Sb-5Te). It summarizes the difference in porosity.

  First, in the case of the heat sink material 10A impregnated with Sb, Sn, Bi as additive elements, there is a difference in density and thermal conductivity as compared with the related art impregnated with pure aluminum, pure copper, and pure nickel. Absent. This is because the addition of the additive element improves the wettability at the interface between the carbon and the metal 14 and improves the adhesion between the carbon and the metal 14.

  On the other hand, the porosity of all the carbons impregnated with pure copper, those impregnated with copper alloy, those impregnated with pure aluminum compared to those impregnated with pure aluminum, It was confirmed that it decreased. This is also because the addition of the additive element improves the wettability at the interface between the carbon and the metal 14 and improves the adhesion between the carbon and the metal 14.

  In addition, each of these samples has a ratio of thermal conductivity in the plane direction to the thickness direction of 1: 5 or less, and has almost isotropic characteristics. There is no need to consider each one, which is advantageous in terms of mounting.

  FIG. 21 summarizes the density of the heat sink material 10A produced at a higher impregnation pressure than the experimental example and the porosity after metal impregnation. In this case, one type of heat sink material 10A (95Sb-5Cu) by the first manufacturing method and one type of heat sink material (4.5Si-95.5Cu) by the conventional technique were examined.

  When the impregnation pressure is increased, it can be seen that, for example, the residual porosity is slightly reduced as compared with the sample shown in FIG. However, when the density of the heat sink material 10A produced by the first manufacturing method is compared with the density of the heat sink material 10A at the low impregnation pressure shown in FIGS. 10 to 20, the increase in the impregnation pressure is the density after the metal impregnation. It can also be seen that the residual porosity is not significantly affected. Instead, as shown in FIG. 21, it is noticed that the residual porosity is greatly reduced by changing the impregnated metal. That is, it is recognized that the effect of changing the impregnated metal is greater than the effect of increasing the impregnation pressure. Therefore, the heat sink material 10A impregnated with the additive metal can realize the heat sink material 10A having a desired porosity and density even at a low impregnation pressure.

  Next, a heat sink material 10B according to a second embodiment will be described with reference to FIG.

  As shown in FIG. 22, the heat sink material 10B according to the second embodiment is formed by mixing carbon or its allotrope powder 12a and metal 14 powder 14a and molding them at a predetermined temperature and a predetermined pressure. ing.

  The carbon or its allotrope has a thermal conductivity of 150 W / mK or higher, preferably 200 W / mK or higher (estimated value without pores), more preferably 250 W / mK or higher (estimated value without pores). ), More preferably 300 W / mK or more (estimated value in the absence of pores). In particular, in the second embodiment, diamond can be used in addition to graphite. In the second embodiment, a heat sink material 10B configured by mixing and molding graphite powder having a thermal conductivity of 100 W / mK or more and copper powder is shown. As the metal 14, it is preferable to use a metal having a property of solidification expansion or a metal having a property of suppressing solidification shrinkage. In addition to Bi, a metal selected from Sb, Ga, graphite cast iron, Metal alloys can be used.

  Further, the heat sink material 10B according to the second embodiment is obtained by mixing the pulverized cutting material of carbon or the allotrope thereof (for example, pulverized cutting material of carbon fiber) and the powder 14a of the metal 14 at a predetermined temperature and a predetermined temperature. It can also be formed by molding under pressure.

  The predetermined temperature is preferably −10 ° C. to −50 ° C. of the melting point of the metal 14 in consideration of forming in a press die, and the predetermined pressure is 10.13 MPa to 101.32 MPa (100 atm. ~ 1000 atmospheres) is preferred.

  The average powder particle size of the carbon or allotrope powder 12a and the metal 14 powder 14a is preferably 1 μm to 500 μm. The volume ratio of carbon or its allotrope and metal 14 is in the range of 20 vol% to 80 vol% for carbon or its allotrope, and 80 vol% to 20 vol% for metal 14. As a result, the heat sink material 10B can be obtained in which the average of the three orthogonal directions or the thermal conductivity in any axial direction is 300 W / mK or more and the porosity is 5%.

  In the heat sink material 10B according to the second embodiment, it is preferable to add an additive that enables re-firing after molding to carbon or an allotrope thereof. Examples of the additive include SiC and / or Si. Thereby, after shaping | molding, re-baking at the temperature more than the melting | fusing point of the said metal 14 is attained. In this case, since the grains generated after the molding are bonded by the re-baking, the grain boundary that inhibits the heat conduction can be almost eliminated, and the heat conductivity of the heat sink material 10B can be improved.

  Moreover, you may make it add the element which reacts with this carbon or its allotrope in carbon or its allotrope. As this additive element, one selected from Ti, W, Mo, Nb, Cr, V, Zr, Be, Al, Ta, Mn, Si, Fe, Co, Ni, Mg, Ca, B, Misch Metal The above can be mentioned. Thereby, a reaction layer (carbide layer) is formed on the surface of carbon or an allotrope thereof at the time of molding or re-firing, and the bonding between grains on the surface of the heat sink material 10B can be improved.

  On the other hand, for the metal 14, it is preferable to select a metal having the property of solidification expansion, for example, one selected from Bi, Sb, Ga, and graphite cast iron, or an alloy made of the metal. As a result, the wettability of the interface between the carbon or its allotrope and the metal 14 is improved, and it is possible to suppress a decrease in shrinkage due to the metal 14 being cooled to the room temperature level. The porosity can be reduced.

  Moreover, it is preferable to add to the metal 14 one or more low melting point metals selected from Nb, Zr, Cr, and Be that are solid-dissolved in copper by 0.5 wt% or less. Thereby, it becomes possible to improve the bonding force between the metals 14 during molding.

  Next, several methods (third and fourth manufacturing methods) for manufacturing the heat sink material 10B according to the second embodiment will be described with reference to FIGS.

  First, the third manufacturing method uses a preforming machine 100 (see FIG. 23) and a hot press machine 102 (see FIG. 24), as specifically shown in FIG. 23 and FIG. Is done by.

  As shown in FIG. 23, the preforming machine 100 includes a mold 112 having a concave portion 110 having an upper opening, and a punch 114 that can be inserted into the concave portion 110 and press-fits the contents in the concave portion 110. Have. Case 70 contains a mixture of carbon or its allotrope powder 12a and metal 14 powder 14a, ie, mixture 104.

  As shown in FIG. 24, the hot press machine 102 includes a lower punch 122 that also serves as a base, and a graphite refractory container 124 having an upper surface opening that is fixed on the lower punch 122. In the refractory container 124, there are provided an upper punch 126 which can be moved forward and backward from above, and a heater 128 for heating the refractory container 124. The refractory container 124 accommodates a preformed body 106 of the mixture 104 formed by the preforming machine 100. The hot press machine 102 is provided with an intake pipe 130 for evacuation.

  Inside the lower punch 122, a passage 132 through which a heating fluid for heating the inside of the refractory container 124 and a cooling fluid for cooling the inside of the refractory container 124 is provided.

  And the 3rd manufacturing method is performed by stepping on the process shown in FIG. First, carbon or its allotrope powder 12a and metal 14 powder 14a are put into a case 70 and mixed to obtain a mixture 104 (step S401), and then the case 70 containing the mixture 104 is preliminarily molded into the preforming machine 100. Is housed in the recess 110 of the mold 112 (step S402). Thereafter, the punch 114 is press-fitted into the recess 110 to preform the mixture 104, thereby forming the preform 106 (step S403).

  Next, the preformed body 106 is taken out from the mold 112, and the preformed body 106 is accommodated in the refractory container 124 in the hot press machine 102 (step S404). After sealing the refractory container 124, the inside of the refractory container 124 is evacuated through the intake pipe 130 to bring the inside of the refractory container 124 into a negative pressure state (step S405). Thereafter, the heater 128 is energized to set the temperature in the refractory container 124 to −10 ° C. to −50 ° C., which is the melting point of the metal 14 (step S406).

  When the temperature reaches the predetermined temperature, the upper punch 126 is moved downward to pressurize the preform 106 to obtain the heat sink material 10B (step S407). Thereafter, it is used as an actual heat sink material 10B through a processing step or the like. However, when an element that enhances the bonding strength between carbon or its allotrope and the metal 14 is added, the element may be heated to the melting point of the metal 14 or higher after the pressurization.

  In addition, since the preferable example of the additive element to carbon or its allotrope and the additive element to the metal 14 has already been described, the detailed description is abbreviate | omitted here.

  Thus, by taking the steps of the third manufacturing method, the average of the three orthogonal directions or the thermal conductivity in any axial direction is 300 W / mK or more, and the porosity is 5%. The following heat sink material 10B can be easily obtained.

  Next, a fourth manufacturing method will be described with reference to FIGS. In the fourth manufacturing method, as shown in FIG. 26, the preforming machine 100 is not used, but only the hot press machine 102 is used.

  That is, as shown in FIG. 27, first, carbon or its allotrope powder 12a and metal 14 powder 14a are put in case 70 and mixed to obtain mixture 104 (step S501). The mixture 104 is directly stored in the refractory container 124 in the hot press machine 102 (step S502). After sealing the refractory container 124, the inside of the refractory container 124 is evacuated through the intake pipe 130 to bring the inside of the refractory container 124 into a negative pressure state (step S503). Thereafter, the heater 128 is energized to set the temperature in the refractory container 124 to −10 ° C. to −50 ° C., which is the melting point of the metal 14 (step S504).

  When the temperature reaches the predetermined temperature, the upper punch 126 is moved downward to pressurize the mixture 104 to obtain the heat sink material 10B (step S505).

  Also in the fourth manufacturing method, the heat sink material 10B having an average of three orthogonal directions orthogonal to each other or a thermal conductivity of 300 W / mK or more in any axial direction and a porosity of 5% or less can be easily obtained. Can get to.

  Next, a heat sink material 10C according to a third embodiment will be described with reference to FIG.

  As shown in FIG. 28, the heat sink material 10C according to the third embodiment pressurizes a mixture of carbon or an allotrope powder 12b and a binder (bonded body) and the like to form a preform and a block (cube). , A rectangular parallelepiped, or any shape), and the block 14 is impregnated with a metal 14. The powder 12b may be the same as the carbon 12 or the allotrope powder 12a used in the second embodiment. This heat sink material 10C can be made into an arbitrary shape close to the final shape.

  As the carbon or allotrope thereof, diamond can be used in addition to graphite. Moreover, as the metal 14, in addition to Bi, Sb, Ga, graphite cast iron, or an alloy containing these metals can be used.

  The average powder particle size of the carbon or allotrope powder 12b is 1 μm to 500 μm, and the ratio of the length between the direction in which the powder 12b takes the minimum length and the direction in which the powder 12b takes the maximum length. Is preferably 1: 5 or less. In this case, although there is no strong network, it can be made into an arbitrary shape close to the final shape. Therefore, it is possible to omit the post-process. The volume ratio between the carbon or its allotrope powder 12b and the metal 14 is preferably in the range of 20 vol% to 80 vol% for the carbon or its allotrope and 80 vol% to 20 vol% for the metal 14.

  Further, it is desirable to add an additive element for reacting with the carbon or its allotrope into the powder 12b of carbon or its allotrope. This additive element may be selected as in the second embodiment.

  It is desirable to use each additive element for the metal 14 as in the case of the first embodiment. That is, an additive element for improving wettability, an additive element for improving the reactivity of carbon or its allotrope with the metal 14, an additive element for reducing the melting point, and the like.

  Next, a fifth manufacturing method according to the third embodiment will be described with reference to FIG. In the fifth manufacturing method, first, water or a binder (binding material) is mixed with carbon or an allotrope powder 12b to prepare a mixture (step S601).

  Then, the mixture is pressurized at a predetermined pressure to form a preform (not shown) (step S602). As a pressurizing device, a press machine 62 (see FIG. 7) or a pre-forming machine 100 (see FIG. 23) may be used.

  Next, a pre-heat treatment is performed to facilitate impregnation of the molten metal 14 into the obtained preform (step S603). For example, if the molten metal 14 is about 1200 ° C., the preheating temperature of graphite is desirably 1000 ° C. to 1400 ° C. By performing this pre-heat treatment, the binder used in step S601 can be removed.

  Further, in step S604, the preform is fired to form a block. The firing method is performed in the same manner as in the first embodiment.

  Then, the molten metal 14 is impregnated in the block (step S605). This impregnation step may be performed in the same manner as each impregnation step shown in the first embodiment. For example, the heat sink material 10C can be obtained by performing the steps S2 to S9 in the first manufacturing method (see FIG. 3) using the high-pressure vessel 30 (see FIG. 2).

  According to the fifth manufacturing method, in the pressurizing process performed in step S602, the thermal expansion coefficient and the thermal conductivity can be controlled to desired values according to the powder compaction state.

  Further, the obtained heat sink material 10C is characterized in that the thermal conductivity becomes more isotropic, and the wettability and the material yield are improved.

  Furthermore, since the metal 14 becomes a network, the strength can be increased and the residual pores can be reduced.

  Furthermore, the heat sink material 10C can be manufactured at low cost. That is, the block before impregnation cannot be processed as it is because it is brittle. However, since the powder preform can be impregnated after being molded into its own shape, and can withstand some subsequent plastic deformation, the heat sink material 10C having a complicated shape can be obtained at a low cost. it can.

  Also in the fifth manufacturing method, the coefficient of thermal expansion can be lowered by adding an element that forms carbide to the metal 14 to be impregnated, as in the case of each of the manufacturing methods described above. Moreover, the impregnation rate can be improved by adding an improving element such as wettability.

  Further, when a high impregnation pressure is applied, the impregnation rate is increased, and the strength and thermal conductivity are also improved.

  Next, a sixth manufacturing method of the heat sink material 10C according to the third embodiment will be described with reference to FIG. In the sixth manufacturing method, first, a dissolved metal in which a metal is dissolved or a metal in a solid-liquid coexisting state (solid-liquid coexisting metal) is prepared (step S701). Here, the solid-liquid coexistence state refers to a metal (generally an alloy) in a semi-molten state, or a metal melt that has been cooled and stirred to a semi-solid state. It refers to both those in a molten state and those that have been completely dissolved and then cooled to a semi-solid state.

  Next, the powder 12b of carbon or an allotrope thereof is mixed with the dissolved metal or the metal in a solid-liquid coexistence state (step S702).

  Then, the heat sink material 10C can be obtained by casting the molten metal 14 or the solid-liquid coexisting metal mixed with the powder 12b and forming it into a desired shape (step S703).

  The heat sink material 10C obtained by the sixth manufacturing method has the same characteristics as those manufactured by the fifth manufacturing method.

  Next, a seventh manufacturing method of the heat sink material 10 according to the present embodiment will be described with reference to FIGS.

  In the seventh manufacturing method, as shown in FIG. 31, the carbon or its allotrope powder 12b is spread in a case 70 made of a material such as graphite, ceramics, or cerapaper, or thereafter, as shown in FIG. In addition, a plate-like lid 92 made of carbon or the like (a hole 94 through which the molten metal flows is formed in advance or porous to prevent the powder 12b in the case 70 from floating when the molten metal is poured). In this state, the powder 12b is impregnated with the metal after preheating as it is.

  Specifically, first, as shown in step S801 of FIG. 31 and FIG. 34, the powder 12b is spread in the case 70. Thereafter, as shown in step S802 of FIGS. 32 and 34, the case 70 is covered with a lid 92 and then preheated. Subsequently, as shown in step S803 of FIGS. 33 and 34, the case 70 (powder 12b is spread) is accommodated in the recess 80 of the press machine 62, and then a molten metal such as copper is formed through the hole 94 of the lid 92. 86 is poured into the case 70. Of course, preheating may be performed without the lid 92, or the molten metal 86 may be poured into the case 70.

  Next, as shown in step S804 of FIG. 33 and FIG. 34, with the lid 92 in place, the punch 84 is inserted into the recess 80, and the molten metal 86 in the case 70 is pushed down to press into the powder 12b. . By the pressing process of the punch 84, the molten metal 86 such as copper is impregnated in the powder 12b.

  The heat sink material 10C obtained by the seventh manufacturing method also has the same characteristics as those manufactured by the fifth manufacturing method.

  Next, an embodiment in which SiC is used for the porous sintered body 12 will be described. First, in the first embodiment (the first manufacturing method, the first modified example, the second modified example, and the second manufacturing method), when SiC is used, graphite is baked to be porous. The process (step S1, step S101, step S201, step S301, and step S302) for producing the sintered material 12 is not necessary, and can be manufactured in the same process in the subsequent steps.

  Furthermore, as an embodiment using SiC for the porous sintered body 12, a manufacturing method (eighth manufacturing method) according to the fourth embodiment will be described with reference to FIGS.

  Specifically, the eighth manufacturing method is performed by using a hot press machine 1060 as shown in an example in FIG. The hot press machine 1060 has substantially the same structure as the hot press machine 102 described in the second embodiment.

  The hot press machine 1060 includes a lower punch 1064 that also serves as a base in a cylindrical casing 1062, a fire-resistant container 1066 having an upper surface opening fixed on the lower punch 1064, and the fire-resistant container 1066 from above. An upper punch 1068 that can freely move back and forth, and a heater 1070 for heating the refractory container 1066 are provided. The hot press machine 1060 is provided with an intake pipe 1072 for evacuation.

  The refractory container 1066 has a cylindrical shape having a hollow portion 1074. The upper punch 1068 is provided with a flange portion 1076 for determining the stroke (stroke) of the upper punch 1068 on its side surface, and the lower surface of the flange portion 1076 is in contact with the upper peripheral surface of the fireproof container 1066 and has a fire resistance. A packing 1078 for sealing the container 1066 is attached. On the other hand, a passage 1080 through which a heating fluid for heating the inside of the refractory container 1066 and a cooling fluid for cooling the inside of the refractory container 1066 is provided inside the lower punch 1064.

  The eighth manufacturing method is carried out by following the steps shown in FIG.

  First, SiC 1020, a porous ceramic filter 1054, and a lump of metal 14 are placed in this order from the bottom into the hollow portion 1074 of the refractory container 1066 (step S1301). As the filter 1054, it is desirable to use a porous ceramic material having a porosity of 40% to 90% and a pore diameter of 0.5 mm to 3.0 mm, and more preferably a porosity of 70% to 85%. It is desirable to use a porous ceramic material having a pore diameter of 1.0 mm to 2.0 mm.

  Further, the filter 1054 functions as a partition plate that separates the SiC 1020 and the metal 14 mass and keeps both in a non-contact state. Of the hollow portion 1074, the metal 14 mass on the filter 1054 is set. The part can be defined as the upper chamber 1074a, and the part where the SiC 1020 under the filter 1054 is set can be defined as the lower chamber 1074b.

  Next, after the refractory container 1066 is sealed, the inside of the refractory container 1066 is evacuated through the intake pipe 1072 to bring the both chambers 1074a and 1074b of the refractory container 1066 into a negative pressure state (step S1302).

  Thereafter, the heater 1070 is energized to heat and dissolve the metal 14 in the upper chamber 1074a (step S1303). At this time, the inside of the refractory container 1066 may be heated by flowing a heating fluid into the passage 1080 of the lower punch 1064 together with the energization of the heater 1070.

  When the melted metal (melted metal) in the upper chamber 1074a reaches a predetermined temperature, the upper punch 1068 is moved downward to pressurize the upper chamber 1074a to a predetermined pressure (step S1304). At this time, due to the contact between the packing 1078 attached to the flange portion 1076 of the upper punch 1068 and the upper peripheral surface of the refractory container 1066 and the mutual pressing, the refractory container 1066 is sealed, and the molten metal 14 inside is sealed in the refractory container 1066. The inconvenience of leaking outside is effectively prevented.

  The melted metal 14 (molten metal 14) in the upper chamber 1074a at a predetermined pressure is pushed out through the filter 1054 to the lower chamber 1074b side by the pressure in the upper chamber 1074a and is introduced into the lower chamber 1074b. SiC 1020 installed in the lower chamber 1074b is impregnated.

  At the stage where the end point set in advance by time management is reached (when the impregnation of the molten metal 14 into the SiC 1020 is saturated), this time, the cooling fluid is caused to flow through the passage 1080 in the lower punch 1064. By cooling the refractory container 1066 from below to above (step S1305), the molten metal 14 impregnated with SiC 1020 is solidified. Until the solidification is completed, the pressurized state in the refractory container 1066 by the upper punch 1068 and the lower punch 1064 is maintained.

  When solidification is completed, SiC 1020 impregnated with metal 14 is taken out of refractory container 1066 (step S1306).

  In the eighth manufacturing method, SiC 1020 and metal 14 are heated while sufficiently degassed to melt metal 14, and then immediately contact SiC 1020, and put them into a pressurized state, and further add Since the pressure state is maintained until the completion of the cooling operation, the SiC 1020 can be efficiently impregnated with the metal 14. In the above example, the impregnation treatment is performed under negative pressure, but it may be performed under normal pressure.

  As described above, since both the molten metal 14 and the SiC 1020 are brought into contact with each other and then brought into contact with each other to perform the impregnation treatment, it is possible to minimize the pressure drop when the two are brought into contact with each other. The pressurization state at the time can be maintained well.

  In the above example, in order to prevent the molten metal 14 from leaking, the packing 1078 is provided on the lower surface of the flange portion 1076 of the upper punch 1068. However, as shown by the two-dot chain line in FIG. A packing 1078 may be provided on the peripheral surface. As shown in FIGS. 37A and 37B, a packing member 1102 in which two ring-shaped split-type packings 1100 are stacked may be provided below the upper punch 1068 as shown in FIG. In this case, the molten metal 14 enters the hollow portion 1104 of the packing member 1102 to increase the diameter of each split packing 1100, and as a result, the upper chamber 1074 a is sealed to prevent the molten metal 14 from leaking. Become.

  Next, a modification of the eighth manufacturing method will be described with reference to FIGS. Note that components corresponding to those in FIG. 35 are denoted by the same reference numerals, and redundant description thereof is omitted.

  In the manufacturing method according to this modified example, as shown in FIG. 39, as a hot press machine 1060, a filter member 1110 made of porous ceramics is fixed to the center in the height direction of the hollow portion 1074 in the refractory container 1066. The door 1112 is attached to the side surface of the lower chamber 1074b so that it can be opened and closed. Therefore, in the hollow portion 1074 of the refractory container 1066, the portion above the filter member 1110 is the upper chamber 1074 a and the portion below the filter member 1110 is the lower chamber 1074 b. In particular, regarding the door 1112 attached to the lower chamber 1074b, a structure is employed in which the lower chamber 1074b is sealed when the door 1112 is closed.

  And the manufacturing method which concerns on this modification is performed by stepping on the process shown in FIG.

  First, a lump of metal 14 is put into the upper chamber 1074a of the refractory container 1066, the door 1112 of the lower chamber 1074b is opened, and SiC 1020 is put into the lower chamber 1074b (step S1401).

  Next, the door 1112 is closed to seal the lower chamber 1074b, and the hot press machine 1060 is further sealed. Then, the inside of the refractory container 1066 is evacuated through the intake pipe 1072, and the chambers 1074a and 1074b of the refractory container 1066 are evacuated. Is set to a negative pressure state (step S1402).

  Thereafter, the heater 1070 is energized to heat and dissolve the metal 14 in the upper chamber 1074a (step S1403). In this case as well, the inside of the refractory container 1066 may be heated by flowing a heating fluid into the passage 1080 of the lower punch 1064 in conjunction with the energization of the heater 1070.

  When the melted metal (melted metal) in the upper chamber 1074a reaches a predetermined temperature, the upper punch 1068 is moved downward to pressurize the upper chamber 1074a to a predetermined pressure (step S1404).

  The melt (molten metal) of the metal 14 in the upper chamber 1074a at a predetermined pressure is pushed out to the lower chamber 1074b through the filter member 1110 by the pressure in the upper chamber 1074a and is introduced into the lower chamber 1074b. SiC 1020 installed in the lower chamber 1074b is impregnated.

  At the stage where the end point is set in advance by the time management, this time, the cooling fluid is allowed to flow through the passage 1080 in the lower punch 1064 to cool the refractory container 1066 from below to above (step S1405). Then, the molten metal 14 impregnated with SiC 1020 is solidified.

  When solidification is completed, SiC 1020 impregnated with metal 14 is taken out of refractory container 1066 (step S1406).

  Also in the manufacturing method according to this modification, SiC 1020 can be efficiently impregnated with metal 14 as in the eighth manufacturing method. Also in this modified example, since both the molten metal 14 and SiC 1020 are put under pressure and then brought into contact with each other to perform the impregnation treatment, the pressure drop when the two are brought into contact can be minimized. The pressure state during the impregnation treatment can be maintained well. In this modification, the impregnation treatment is performed under negative pressure, but it may be performed under normal pressure.

  Furthermore, as an embodiment in which SiC is used for the porous sintered body 12, a manufacturing method (a ninth manufacturing method) according to the fifth embodiment will be described with reference to FIGS. Note that components corresponding to those in FIG. 35 are denoted by the same reference numerals, and redundant description thereof is omitted.

  The ninth manufacturing method is substantially the same as the manufacturing method according to the fourth embodiment in principle, but in the impregnation step, SiC 1020 and the metal 14 are brought into contact with each other under a negative pressure or a normal pressure and heated. The difference is that the metal 14 is melted by processing.

  Specifically, the SiC 1020 from the bottom without putting the filter 1054 into the refractory container 1066 of the hot press 1060 used in the eighth manufacturing method according to the third embodiment shown in FIG. The difference is that the metals 14 are introduced in this order.

  And the 9th manufacturing method concerning a 5th embodiment is performed by stepping on the process shown in FIG.

  First, SiC 1020 and a lump of metal 14 are placed in this order from the bottom into the hollow portion 1074 of the refractory container 1066 (step S1501).

  Next, after the hot press machine 1060 is sealed, the inside of the refractory container 1066 is evacuated through the intake pipe 1072 to bring the inside of the refractory container 1066 into a negative pressure state (step S1502).

  Thereafter, the heater 1070 is energized to heat and melt the metal 14 in the refractory container 1066 (step S1503). At this time, the inside of the refractory container 1066 may be heated by flowing a heating fluid into the passage 1080 of the lower punch 1064 together with the energization of the heater 1070.

  When the melted metal (molten metal) in the refractory container 1066 reaches a predetermined temperature, the upper punch 1068 is moved downward to pressurize the refractory container 1066 to a predetermined pressure (step S1504).

  The melted metal 14 (molten metal) at a predetermined pressure is impregnated in SiC 1020 by the pressure in the refractory container 1066.

  At the stage where the end point set in advance by time management is reached (when the impregnation of the molten metal 14 into the SiC 1020 is saturated), this time, the cooling fluid is caused to flow through the passage 1080 in the lower punch 1064. By cooling the refractory container 1066 from below to above (step S1505), the molten metal 14 impregnated with SiC 1020 is solidified. Until the solidification is completed, the pressurized state in the refractory container 1066 by the upper punch 1068 and the lower punch 1064 is maintained.

  When solidification is completed, SiC 1020 impregnated with metal 14 is taken out from refractory container 1066 (step S1506).

  Also in the ninth manufacturing method, SiC 1020 and metal 14 are heated while sufficiently deaerated, and after melting metal 14 in a state where metal 14 and SiC 1020 are in contact with each other, the inside of refractory container 1066 is in a pressurized state. In addition, since the pressurized state is maintained until the completion of the cooling operation, it is possible to efficiently impregnate the SiC 1020 with the metal 14.

  The heat sink material according to the present invention is not limited to the above-described embodiment, but can of course have various configurations without departing from the gist of the present invention.

It is a perspective view which shows the structure of the heat sink material which concerns on 1st Embodiment. FIG. 2A is a diagram showing a partially broken front view of the high-pressure vessel used in the first manufacturing method, and FIG. 2B is a diagram showing a partially broken side view of the high-pressure vessel. It is a process block diagram showing the 1st manufacturing method. It is a process block diagram showing the 1st modification of the 1st manufacturing method. It is a process block diagram showing the 2nd modification of the 1st manufacturing method. It is a block diagram which shows the furnace used with a 2nd manufacturing method. It is a block diagram which shows the press used by the 2nd manufacturing method. It is a process block diagram showing the 2nd manufacturing method. It is sectional drawing of the IV-IV line direction of the heat sink material shown in FIG. It is a figure which shows the density in the impregnation location of the heat sink material shown in FIG. It is a figure which shows the density in the impregnation location of the heat sink material shown in FIG. It is a figure which shows the density in the impregnation location of the heat sink material shown in FIG. It is a figure which shows the density in the impregnation location of the heat sink material shown in FIG. It is a graph which shows the characteristic of the heat sink material which concerns on a 2nd manufacturing method. It is a graph which shows the characteristic of the heat sink material which concerns on a 2nd manufacturing method. It is a graph which shows the characteristic of the heat sink material which concerns on a 2nd manufacturing method. It is a graph which shows the characteristic of the heat sink material which concerns on a 2nd manufacturing method. It is a figure which shows the porosity and density of the heat sink material which concern on a 2nd manufacturing method. It is a figure which shows the porosity and heat conductivity of the heat sink material which concern on a 2nd manufacturing method. It is a figure which shows the porosity and density of the heat sink material which concern on a 2nd manufacturing method. It is a figure which shows the porosity and density when an impregnation pressure is changed in the heat sink material which concerns on a 2nd manufacturing method. It is a perspective view which shows the structure of the heat sink material which concerns on 2nd Embodiment. It is a block diagram which shows the preforming machine used with the 3rd manufacturing method. It is a block diagram which shows the hot press machine used with the 3rd manufacturing method. It is a process block diagram showing the 3rd manufacturing method. It is a process block diagram showing the 4th manufacturing method. It is a block diagram which shows the hot press machine used with the 4th manufacturing method. It is a perspective view which shows the structure of the heat sink material which concerns on 3rd Embodiment. It is a process block diagram showing the 5th manufacturing method. It is a process block diagram showing the 6th manufacturing method. It is explanatory drawing which shows the state which spread the powder in the case in the 7th manufacturing method. In a 7th manufacturing method, it is explanatory drawing which shows the state which put the lid | cover in the case. In a 7th manufacturing method, after pouring molten metal in a case, it is explanatory drawing which shows the state which pushes down molten metal with a punch. It is a process block diagram showing the 7th manufacturing method. It is a schematic block diagram which shows the hot press machine used for the 8th manufacturing method. It is a process block diagram showing the manufacturing method concerning a 4th embodiment. 37A is a plan view showing the packing member, and FIG. 37B is a cross-sectional view taken along the line XXVIIB-XXVIIB in FIG. 37A. It is a schematic block diagram which shows the other example of the hot press used for the 8th manufacturing method. It is a schematic block diagram which shows the hot press machine used for the modification of the 8th manufacturing method. It is a process block diagram showing a modification of the eighth manufacturing method. It is a schematic block diagram which shows the hot press machine used for the 9th manufacturing method. It is a process block diagram showing the 9th manufacturing method.

Explanation of symbols

10A, 10B, 10C ... heat sink material 10a to 10f ... impregnation location 12 ... porous sintered body 12a, 12b ... powder of carbon or its allotrope 14 ... metal (molten metal) 14a ... metal powder 30 ... high pressure vessel 32, 120 1062 ... Case 34,36 ... Side plate 38 ... Rotating shaft 40,124,1066 ... Fireproof container 42,74,128,1070 ... Heater 44,1074,1104 ... Hollow part 44a ... First chamber 44b ... Second chamber 46 ... Opening 48, 130, 1072 ... Intake pipe 50 ... Gas inlet pipe 52 ... Gas outlet pipe 60 ... Furnace 62 ... Pressing machine 70 ... Case 72 ... Space 80,110 ... Concavity 82,112 ... Die 84,114 ... Punch 86 ... Molten metal 88, 90 ... Degassing holes 100 ... Pre-forming machine 102, 1060 ... Hot press machine 104 ... Mixture 106 ... Pre-forming Body 122, 1064 ... Lower punch 126, 1068 ... Upper punch 132, 1080 ... Passage 1020 ... SiC
1054 ... Filter 1074a ... Upper chamber 1074b ... Lower chamber 1076 ... Flange 1078 ... Packing 1100 ... Split packing 1102 ... Packing member 1110 ... Filter member 1112 ... Door

Claims (10)

In a heat sink material containing carbon or graphite and metal,
The carbon or graphite powder is mixed with water or a binder and molded into a preform or fired molded body, impregnated with a melt of the metal at a pressure of 1.01 MPa to 202 MPa,
The average powder particle size of the carbon or graphite powder is 1 μm to 500 μm,
The average of the ratio of the length in the direction in which one particle constituting the powder has the minimum length and the direction in which the maximum length is taken is 1: 5 or less,
The metal is said Bi or S b wettability with good properties for carbon or graphite, when all metal components is 100%, the heat sink material, characterized in that it comprises 60% or more. In a heat sink material containing carbon or graphite and metal,
The carbon or graphite powder and the metal powder are mixed and formed under a pressure of 10.13 MPa to 101.32 MPa.
The average powder particle size of the carbon or graphite powder is 1 μm to 500 μm,
The average of the ratio of the length in the direction in which one particle constituting the powder has the minimum length and the direction in which the maximum length is taken is 1: 5 or less,
The metal is said Bi or S b wettability with good properties for carbon or graphite, when all metal components is 100%, the heat sink material, characterized in that it comprises 60% or more. In a heat sink material containing carbon or graphite and metal,
The liquid or solid-liquid coexisting substance obtained by dissolving the metal is mixed with the carbon or graphite powder, and is formed by casting,
The average powder particle size of the carbon or graphite powder is 1 μm to 500 μm,
The average of the ratio of the lengths in the direction in which one particle constituting the powder has the minimum length and the direction in which the maximum length is taken is 1: 5 or less;
The metal is said Bi or S b wettability with good properties for carbon or graphite, when all metal components is 100%, the heat sink material, characterized in that it comprises 60% or more. In a heat sink material containing carbon or graphite and metal,
The carbon or graphite powder is impregnated with the metal,
The average powder particle size of the carbon or graphite powder is 1 μm to 500 μm,
The average of the ratio of the lengths in the direction in which one particle constituting the powder has the minimum length and the direction in which the maximum length is taken is 1: 5 or less;
The metal is said Bi or S b wettability with good properties for carbon or graphite, when all metal components is 100%, the heat sink material, characterized in that it comprises 60% or more. In a heat sink material containing carbon or graphite and metal,
The carbon or graphite pulverized cutting material and the metal powder are mixed and formed under a pressure of -10 ° C to -50 ° C, 10.13 MPa to 101.32 MPa of the melting point of the metal,
The metal is said Bi or S b wettability with good properties for carbon or graphite, when all metal components is 100%, the heat sink material, characterized in that it comprises 60% or more. In the heat sink material according to any one of claims 1 to 5,
The heat sink material, wherein the volume ratio of the carbon or graphite and the metal is in the range of 20 vol% to 80 vol% for the carbon or graphite and 80 vol% to 20 vol% for the metal. In the heat sink material according to any one of claims 1 to 6,
An element selected from Te, Sn, Pb, Se, Li, Tl, and Cd is added in order to reinforce the metal bond when the heat sink material is formed. The heat sink material according to claim 7,
The heat-sink material is characterized in that the added element is an element that dissolves in copper only by 0.5 wt% or less. In the heat sink material according to any one of claims 1 to 8,
Nb, Zr, Cr, Be, V, Mo, Al, Ta, Mn, Si, Fe, Co, Ni, Mg, Ca, in order to strengthen the bond between carbon or graphite and metal during the molding. A heat sink material, wherein one or more elements selected from W, Ti, B, and misch metal are added to the metal. In the heat sink material according to any one of claims 1 to 9,
In order to allow the carbon or graphite to be reheated after molding, Nb, Zr, Cr, Be, V, Mo, Al, Ta, Mn, Si, Fe, Co, Ni, Mg, Ca, W, One or more elements selected from Ti, B, and Misch metal are added to the metal,
The heat sink material is formed based on a reaction between at least the carbon or graphite and the added one or more elements.

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