JP2001294494A - Metal ceramic composite and heat dissipation member - Google Patents

Abstract

(57) Abstract: Provided are a metal-ceramic composite and a heat radiation member having high thermal conductivity, low thermal expansion coefficient, and the like, which are useful for semiconductor device applications. A metal-ceramic composite formed by impregnating a porous ceramic sintered body with a molten metal under pressure. The porous ceramics sintered body is a network-like skeleton structure in which ceramic particles are connected to each other by diffusion bonding (an average cross-sectional diameter of a bonding portion is preferably 1 μm or more). size _{L M} 500
~6000μm ^2, the distribution density _{D M} of the island-like metal portion 20
It has a composite structure of 40 area%. What is an island-shaped metal part?
Each island-shaped portion of impregnated metal distributed in islands surrounded by the skeletal structure of the ceramic sintered body, observed in the cross section of the composite,
The area of the metal phase is the sum of the areas of the island-shaped metal parts. _{L M = S M / N M} [S M: area of the metal phase (μm ^2), N
_M : total number of island-shaped metal parts (pieces)]

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is useful as a metal ceramic composite obtained by impregnating a porous ceramic sintered body with a metal, typically as a heat sink material for semiconductor parts such as semiconductor circuit boards and integrated circuit packages. The present invention relates to a composite and a heat radiating member having high thermal conductivity and low thermal expansion.

[0002]

2. Description of the Related Art With the miniaturization of electronic equipment, high-density integration of semiconductor devices, and high-speed operation in the field of semiconductor devices, the heat generation density of semiconductor elements tends to increase significantly. The temperature rise due to the heat generated by the semiconductor element causes a malfunction and a destruction of the circuit (exfoliation of the interface between the element and the insulating substrate due to thermal stress). As a means for preventing this and stabilizing the operating characteristics, it is common to use a package in which a heat dissipating member for dissipating heat generated from the element is laminated and joined to the back surface of an insulating substrate (made of ceramics) on which the semiconductor element is mounted. . The demand for a heat radiation effect for devices that generate a large amount of heat due to a large current, such as power devices such as high-output inverters, is becoming more severe. The heat dissipating member has high thermal conductivity,
Insulating substrates for semiconductor devices (silicon nitride, aluminum nitride,
It is required that the insulating substrate has a low coefficient of thermal expansion close to the coefficient of thermal expansion of the insulating substrate so that a sound contact state of the laminated interface with the laminated substrate is maintained.

As the heat dissipating member, a metal ceramic composite in which a porous ceramic sintered body is impregnated with a high heat conductive metal such as aluminum has been proposed. As a device for further improving the heat radiation characteristics, a composite produced by spontaneously impregnating a molten aluminum having an improved wettability with ceramics by adding an impregnation accelerator in a non-oxidizing atmosphere (Japanese Patent Laid-Open No. -215935), a composite in which an element such as magnesium is added to aluminum to form a crystallized region in an intermediate layer at the contact interface between the impregnated metal and the ceramic so as to increase the thermal conductivity (JP-A-11-115) No. 139889) has been proposed. These all increase the thermal conductivity of the composite as an effect of improving the physical properties of the impregnated metal.

[0004]

SUMMARY OF THE INVENTION The inventors of the present invention have been conducting various studies with the aim of improving the thermal characteristics of a metal-ceramic composite, and have found that the thermal conductivity of the composite is a composite ratio of the ceramic and the impregnated metal. Unlike the conventional wisdom of relying only on the particle, the bonding form of the particles of the ceramic sintered body has a great effect on the thermal conductivity of the composite, and the thermal expansion coefficient has been further reduced as a control effect of the particle bonding. Obtained knowledge. The present invention has been made based on these findings.

[0005]

The metal-ceramic composite of the present invention is a composite formed by impregnating a porous ceramic sintered body with a molten metal under pressure. Is a network-like skeletal structure in which ceramic particles are connected by diffusion bonding, and the impregnated metal has an average size L _M of the island-shaped metal portion calculated by the following equation.
There is 500~6000μm ^2, and the distribution density _{D M} of the island shaped metal part has a composite structure which is 20 to 40 area%. During L _M = _{S M} / _{N M-type, S M:} area of the metal phase (μm ²⁾ N _M: total number of island-like metal portions (pieces) where an island-like metal portion was observed in the cross section of the composite Each of the island-shaped portions of the impregnated metal distributed in the shape of an island surrounded by the network skeleton structure of the ceramic sintered body is designated, and the "area of the metal phase" is the total area of the island-shaped metal portions. The observation field of view is
The area is 1.0 mm ² or more.

In the porous ceramic sintered body which is the skeleton structure of the metal-ceramic composite of the present invention, the ceramic particles are interconnected by diffusion bonding (there is no heterogeneous phase which hinders heat conduction at the bonding interface). It has a three-dimensional network structure with good adhesion. By this particle bonding form,
Heat conduction using the ceramic skeleton structure as a heat transfer path is promoted. The metal phase impregnated with pressure has high adhesion to the ceramic structure and is dense. As these effects, improved heat radiation characteristics due to high thermal conductivity are exhibited.

The ceramic sintered body forming the skeletal structure has a strong skeletal structure and high strength and rigidity as an effect of having a bonding form with good adhesion formed by diffusion of particles. For this reason, the skeletal structure is not damaged even if it is subjected to the pressure action when the molten metal is impregnated by the pressure casting method. Further, the high strength and high rigidity of the skeletal structure effectively acts as a restraining / suppressing force against the thermal expansion of the impregnated metal in the actual use of the metal-ceramic composite. Thereby, the metal-ceramic composite of the present invention stably maintains a low coefficient of thermal expansion.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows a particle bonding form of a porous ceramic sintered body which is a skeleton structure of a metal ceramic composite of the present invention. Ceramic particles (1) form a rigid skeleton structure by coupling to one another via a coupling part by diffusion (1 _1).
In order to further clarify the improved thermal characteristics (high thermal conductivity and low thermal expansion coefficient) of the product metal-ceramic composite brought as an effect of this skeletal structure, the bonding surface of the diffusion bonding part (1 ₁ ) has a cross section. The diameter is preferably 1 μm or more (average cross-sectional diameter).

FIG. 2 schematically shows a metal / ceramic composite structure appearing in a cross section of the composite of the present invention. 2
(Dotted pattern portion) is a ceramic sintered body, and 3 (uncoated portion) is an impregnated metal. The impregnated metal (3) is in the form of an island-like distribution surrounded by the skeletal structure of the ceramic sintered body (2), and the island-like portions are three-dimensionally continuous with each other. The average size L _M (= S _M / N _M ) of the island-shaped metal portion is
A 500～6000Myuemu ^2, the distribution density _{D M} 2
0 to 40% (area ratio). Measurement of the average size L _M and the distribution density D _M of island-like metal part can be performed using the image processing apparatus. In order to increase the reliability of the numerical values, the observation visual field is set to have a width of 1.0 mm ² or more.

By defining the composite structure of the metal ceramic composite as described above, an improved high thermal conductivity
A low coefficient of thermal expansion is ensured. In addition, since the composite has few closed pores, the plating is performed directly on the surface of the composite when applied as a heat dissipating member for an electronic element (plating is necessary for solder bonding of an insulating substrate). In this case as well, a plating film having uniformity and good smoothness can be formed, and good solder jointability can be secured.

As the porous ceramic sintered body having the skeleton structure of the metal ceramic composite of the present invention, a porous sintered body produced by a recrystallization sintering method is suitably used.
According to the recrystallization sintering method, there is no need to mix a sintering aid,
A porous sintered body interconnected by diffusion bonding between the ceramic particles is obtained, and no heterogeneous phase that hinders heat conduction is interposed at the particle bonding interface. The bonding state of the particles is controlled by the sintering conditions (temperature, time, particle size of the raw material particles, etc.). For example, to produce a porous sintered body of silicon carbide (SiC), silicon carbide powder (for example, having an average particle diameter of 10 to 30 μm) is formed by an appropriate molding method, for example, a casting method (slip casting), a pressure molding method ( (Uniaxial press etc.) to obtain a porous molded body of the required shape,
The treatment is successfully performed in a temperature range of 0 to 2500 ° C. for an appropriate time (about 1 to 3 hours), and it is easy to form a diffusion bond having an average cross-sectional diameter of a bonding portion between particles of 1 μm or more.

The ceramic material of the porous ceramic sintered body is selected from a wide range such as carbide, nitride, oxide and boride. Silicon carbide (SiC), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), alumina (Al ₂ O ₃ ), etc. are preferably used because they have a low coefficient of thermal expansion and a relatively high coefficient of thermal conductivity.

The impregnated metal is aluminum (thermal conductivity: about
234 W / m · K, coefficient of thermal expansion: about 23.5 × 10 ⁻⁶ / K), copper (thermal conductivity: about 393 W / m · K, coefficient of thermal expansion: about 17 × 10 ⁻⁶ / K) K) as a main component, or a high heat conductive metal such as magnesium (thermal conductivity: about 155 W / m · K, thermal expansion coefficient: about 26 × 10 ⁻⁶ / K).

As a specific example of the composite of the present invention, SiC, AlN, Si ₃ N ₄ or Al
A composite manufactured by impregnating a porous ceramics sintered body made of ₂ O ₃ with a metal mainly containing aluminum, a metal mainly containing copper, or a metal mainly containing magnesium is exemplified. . Depending on the type of ceramic and impregnated metal, thermal conductivity: 180 W / m
K or more, thermal expansion coefficient: 7.5 × 10 ⁻⁶ / K or less, thermal diffusivity: 0.75 cm ² / sec or more, can be used as a heat dissipating member for electronic elements. You. In particular, SiC (thermal conductivity of about 170 to 270 W
/ M · K, a thermal expansion coefficient of about 4.5 × 10 ⁻⁶ / K), a composite produced by impregnating a metal containing aluminum as a main component into a recrystallized porous sintered body is a heat dissipating member for electronic elements. Is very suitable.

FIG. 3 shows an example of a heat radiating member for an electronic device using the metal-ceramic composite of the present invention. 4 is
A substrate made of a metal-ceramic composite (hereinafter, also referred to as a “composite substrate”) is an insulating substrate for mounting a semiconductor element, and a composite substrate (4) is provided on the plate surface on which the insulating substrate 10 is mounted. Plating (typically nickel plating) is performed, and the insulating substrate (10) is solder-bonded on the plated surface, and plating on the plate surface of the composite substrate (4) enhances solder adhesion. The metal-ceramic composite has a composite structure composed of ceramics and metal, so that plating is uniformly formed on the plate surface. Although it is usually difficult to perform the plating, the composite of the present invention is easy to be plated as described above, so that a uniform and smooth plating film is formed and a good solder joint of the insulating substrate is formed. It is possible .

FIGS. 4 and 5 show another example of a heat radiating member for an electronic device using the metal-ceramic composite of the present invention (FIG. 4: front view, FIG. 5: plan view). The composite substrate (4) has a metal layer (5) formed on one plate surface thereof. The surface of the metal layer (5) is plated, and the insulating substrate (10) is soldered on the plating film.

Plating on the metal layer (5) is easy, and a uniform and good-plating plating film can be formed to ensure good solder adhesion for the stacked bonding of the insulating substrate (10). . The thickness of the metal layer (5) is about 10 μm or more.
What is necessary is just about 5 mm.

The metal layer (5) covers the entire surface of the composite substrate (4).
It does not need to be provided on the body, and the insulating substrate (10) is loaded
It is sufficient if it is formed in the region. In the heat dissipating member of FIG.
Indicates a region other than the loading region of the insulating substrate (10) (composite base
Left and right side edge regions 6 of plate 4 ₁) Indicates the metal layer (5)
The plate surface (4) of the composite substrate (4)₁) Exposed in a band
Given the form.

The provision of the portion (hereinafter, “uncovered portion”) (6 ₁ ) having no metal layer (5) is caused by the thermal expansion caused by the coefficient of thermal expansion between the metal layer (5) and the composite substrate (4). It is effective for absorbing and relaxing stress. The uncovered portion is formed with an appropriate pattern in an area other than the loading area of the insulating substrate (10). For example, as shown in FIG. 5, together with the non-covered portion of the left and right end region which is outside the Noseki region of the insulating substrate (10) (6 _1), or in place of the non-covered portion _(61), Between the rows of the insulating substrate (10), band-shaped or streak-like uncovered portions (6 ₂ ) (6 ₃ ) indicated by chain lines are provided as necessary. As a measure to balance the thermal stress for suppressing and preventing the thermal deformation of the composite substrate (4), the above-mentioned uncoated portion (6) is used.
Instead of the formation of _{1-6 3),} or non-covered portion ₍₆ 1 -
6 ₃₎ in conjunction with the formation of, as shown in FIG. 4, it is also effective to provide the thick portion of the metal edge (8) of the composite substrate (4).

As shown in FIGS. 3 and 4, the heat dissipating member protrudes from the plate surface opposite to the plate surface on which the insulating substrate (10) is mounted in a direction perpendicular to the plate surface as a heat dissipating design. Radiation fins (fin-shaped metal protrusions) (7) are provided as needed.

The metal-ceramic composite and the heat dissipating member of the present invention are efficiently produced by using a pressure casting method (such as a squeeze casting method). According to the pressure casting method, the porous ceramic sintered body is impregnated with the molten metal under pressure (formation of a composite) and the formation of the metal layer (5) and the heat radiation fin (7) required for the heat radiation member. At the same time, the heat dissipation member can be manufactured as an integrated product.

FIG. 6 shows an example of manufacturing the composite and heat dissipating member of the present invention by pressure casting. In the figure, reference numeral 20 denotes a mold (consisting of an upper mold and a lower mold; runners, gas vent holes, etc. are not shown); and 30, a preform (porous ceramic sintered body); Is the support pin (21)
Through the mold cavity (22).
The cavity (2) of the mold (20) in this example was
2) The space for forming the radiation fin ₍₂₂ 1)
Are provided in a direction orthogonal to the plate surface of the preform (30). The molten metal is slowly filled into the cavity (22) via a runner (not shown), and then pressurized to promote impregnation of the preform (30). It is appropriate that the pressure is adjusted to about 50 to 100 MPa, and the impregnation speed (speed at which the molten metal passes through the gate) is adjusted to about 1.0 m / sec or less. Pressure impregnation and fin shaping (casting) are achieved in a short time (several seconds).

After the molten metal is solidified, it is removed from the mold, and excess metal is removed by machining to obtain a heat radiating member having the form shown in FIG. 3 or FIG. The thickness of the metal layer (5) on which the insulating substrate is mounted is adjusted by machining. The uncoated portions (6 ₁ ) to (6 ₃ ) are appropriately shaped in a mold in advance so that the metal layer at those portions is removed by machining or the molten metal does not come into contact with the portions to be uncoated portions. It is formed by providing ribs.

In the heat dissipation member thus obtained, the composite substrate (4), the metal layer (5) and the heat dissipation fins (7) have continuous integrity. In an assembly structure in which the metal layer (5) and the heat radiation fins (7) are bonded to the plate surface of the composite substrate as in a conventional heat dissipating member, the bonding interface is discontinuous, and the existence of the interface becomes a barrier to heat conduction. However, the heat dissipating member of the present invention having an integrally molded structure does not have such a drawback and is advantageous for enhancing heat dissipating characteristics.

Moreover, the semiconductor package formed by soldering the insulating substrate (10) to the metal layer (5) of the heat dissipating member is cracked and peeled off at the solder bonding interface even if it is affected by the temperature rise and fall in actual use. It shows stability without causing. This solder crack resistance is due to the fact that the ceramic skeleton structure has high strength and high rigidity as an effect of its particle bonding form and effectively acts as a restraining force for suppressing thermal deformation of the metal layer (5). it is conceivable that.

[0026]

EXAMPLES [1] Production of porous ceramics sintered body (preform) Each of the test preforms was a plate-like body (10%) having a porosity of 25%.
0 × 150 × 5, mm). Preform A1: SiC powder (average particle size 15 μm)
And recrystallized and sintered (2400 ° C x 3H)
r). FIG. 8 shows the particle binding structure of the preform A1 (magnification × 100). In the figure, the gray white part is ceramics, and the black part is pores. Diffusion bonding (SiC bonding) between particles
Are linked by The average cross-sectional diameter of the joint is 3.5 μm
It is.

Preform A2: Powder compaction of SiC powder (average particle diameter 20 μm) (uniaxial press, molding pressure 10MP)
a) and recrystallized and sintered (1800 ° C. × 3 hours). The particles of the porous sintered body are connected by diffusion bonding (SiC bonding), but the average cross-sectional diameter of the bonding part is 0.5 μm due to insufficient recrystallization reaction.

Preform B1: 2 parts by weight of silica sol (in terms of SiO 2) as a sintering agent was added to 100 parts by weight of SiC powder (average particle size: 28 μm), and after compacting (uniaxial pressing, molding pressure of 10 MPa) , Atmosphere sintering (1
200 ° C. × 3 hr). This porous sintered body has no diffusion bonding (SiC bonding) of particles and is interconnected (SiO ₂ bonding) via an SiO ₂ phase.

Porous sintered body B2: To 100 parts by weight of SiC powder (average particle size 28 μm), 10 parts by weight (converted to C) of a phenol resin was added as a sintering aid, followed by compacting (uniaxial pressing, forming). After a pressure of 10 MPa), an atmosphere sintering process (1900 ° C. × 3 hours) is performed. This porous sintered body has no diffusion bonding (SiC bonding) of particles and is interconnected (carbon bonding) through carbon.

(2) Metal impregnation treatment A preform is impregnated with a molten aluminum alloy (material type: JIS H5202 AC4C) by a pressure casting machine (squeeze cast). Melt temperature: 750 ° C. Pressure: 70 MPa Impregnation speed: 0.1 m / sec After solidification of the molten metal, it is punched out and machined to obtain the test material shown in FIG. Composite substrate (4): 100 × 150 × 5, mm Metal layer (5): Layer thickness 1 mm

For each of the test heat radiating substrates, the thermal characteristics of the composite substrate (4) were measured and the following solder crack resistance evaluation test was performed. (3) Solder crack resistance test Preparation of test material: After nickel plating is applied to the surface of the metal layer (5) of the test heat dissipating member, the insulating substrate (AlN ceramics) is soldered (Pb60Sn solder). Test method: Heating from −40 ° C. to 125 ° C. was repeated in one cycle (40 minutes / cycle), and 3000 cycles were repeated.
After the test, the presence or absence of cracks in the solder joint surface
It is determined by M observation, X-ray analysis and ultrasonic analysis.

(4) Composite Structure and Thermal Property Test Results of Test Material (4.1) Composite Structure FIGS. 9 to 12 show the composite structure of each test material (FIG. 9: invention example, FIG. 10: comparative example) No. 11, FIG. 11: Comparative Example No. 12,
FIG. 12: Comparative Example No. 13). The invention examples are significantly different from each of the comparative examples in the network structure of the ceramic skeleton structure and the distribution form of the impregnated metal. This unique composite form is based on the specificity of the particle binding form of the ceramic skeleton structure.

(4.2) Thermal Property Test Results Table 1 shows the thermal properties and the results of the solder crack resistance test, together with the composite forms of the test materials.

[0034]

[Table 1]

The composite of the invention has both high thermal conductivity and low thermal expansion coefficient, and also has excellent solder crack resistance.
The high thermal conductivity is due to the effect of the particle bonding form of the ceramic skeleton structure (particles are connected to each other by diffusion bonding and the cross-sectional diameter of the bonding part is large) so that the skeleton structure functions as a heat transfer path. In addition, the metal phase impregnated with pressure is dense and has good adhesion to the ceramic skeleton structure. Further, the coefficient of thermal expansion is low because the ceramic skeleton structure has high strength and high rigidity as an effect of its particle bonding form, and has a strong binding force for suppressing thermal expansion of the impregnated metal. Further, it is considered that the reason for the excellent solder crack resistance is that the high strength and high rigidity of the ceramic skeleton structure effectively work as a restraining force for suppressing the thermal deformation of the metal layer (5). .

The composites of Comparative Examples No. 11 and No. 12
Although it is composed of ceramics and impregnated metal of the same material type as the invention example, the thermal conductivity is lower and the thermal expansion coefficient is higher than that of the invention example, because the bonding between the particles forming the ceramic skeleton structure is small. Since the bonding structure uses an intervening phase derived from a sintering aid as a binder instead of diffusion bonding, the heat conduction effect using the skeletal structure as a heat transfer path is small, and the skeletal structure against thermal expansion of the impregnated metal is also used. This is because the binding force is not sufficient. The inferior solder crack resistance is considered to be due to the lack of strength and rigidity of the ceramic skeleton structure and insufficient binding force to the thermal expansion of the metal layer (5).

Comparative Example No. 13 uses a porous sintered body obtained by the same recrystallization sintering method as the invention example, but has little effect of improving the thermal conductivity and the coefficient of thermal expansion, and has a low solder crack resistance. Not enough. This is because the cross-sectional diameter of the diffusion bonding portion between the particles of the ceramic skeleton structure is small, and the effect based on the ceramic skeleton structure as in the invention example is insufficient.

[0038]

The metal-ceramic composite of the present invention has a high thermal conductivity and a low coefficient of thermal expansion, and is excellent in the solder adhesion of an insulating substrate to be soldered via a metal layer. It is useful as a heat dissipating member, and can stably maintain a function as a semiconductor package formed by soldering an insulating substrate for mounting a semiconductor circuit. The composite of the present invention is also useful as a metal or ceramic substitute material in various fields requiring high thermal conductivity and low thermal expansion coefficient.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a diffusion bonding portion between particles of a porous ceramic sintered body.

FIG. 2 is a view schematically showing a metal / ceramic composite form appearing in a cross section of the metal-ceramic composite of the present invention.

FIG. 3 is a front view showing an example of a heat dissipation member using the metal-ceramic composite of the present invention.

FIG. 4 is a front view showing another example of a heat dissipation member using the metal-ceramic composite of the present invention.

FIG. 5 is a plan view of the heat radiation member of FIG. 4;

FIG. 6 is a front sectional view showing a production example of the metal-ceramic composite of the present invention by pressure casting.

FIG. 7 is a front view showing a form of a test material of an example.

FIG. 8 is a micrograph (magnification × 100) showing a particle bonding structure of a porous ceramic sintered body constituting the metal-ceramic composite of the present invention.

FIG. 9 is a micrograph (magnification × 100) showing a composite structure of the metal-ceramic composite of the present invention.

FIG. 10 shows comparative material Nos. 11 is a photomicrograph (magnification × 100) showing a composite structure of a metal-ceramic composite of No. 11;

FIG. 11 shows comparative material Nos. 12 is a photomicrograph (magnification × 100) showing a composite structure of a metal-ceramic composite of No. 12;

FIG. 12 shows comparative material Nos. 13 is a micrograph (magnification × 100) showing a composite structure of a metal ceramic composite of No. 13;

[Explanation of symbols]

1: Ceramic particles 11 ₁ : Diffusion bonding part of ceramic particles 2: Skeletal structure composed of ceramic sintered body 3: Impregnated metal 4: Metal ceramic composite 41 ₁ : Plate surface of metal ceramic composite 5: Metal layer 6 ₁ , 6 ₂ , 6 ₃ : non-coated portion (without metal layer) 7: radiating fin 10: insulating substrate 20: pressure casting mold 21: support pin 22: cavity 22 ₁ : fin forming space 30: preform ( Porous ceramic sintered body)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroaki Okano 1-1-1, Nakamiya Oike, Hirakata City, Osaka Prefecture Inside the Kubota Hirakata Plant Co., Ltd. (72) Inventor Akira Kosaka 1-1-1, Nakamiya Oike, Hirakata City, Osaka Prefecture No. 1 F-term in Kubota Hirakata Plant (reference) 5F036 BB05 BB21

Claims (9)

[Claims] 1. A metal ceramic composite formed by impregnating a porous ceramic sintered body with a molten metal under pressure, wherein the porous ceramic sintered body is formed by connecting ceramic particles by diffusion bonding. comprising a network structure structure, impregnated metal, the average size _{L M} of the island-like metal part which is calculated by the following equation, the distribution density _{D M} is 20-40 area 500～6000Myuemu ^2, island-like metal portion % Of a metal-ceramic composite having a composite structure of about 50%. _{L M = S M / N M} [ wherein, _{S M:} area of the metal phase (μm ²⁾ N _M: total number of island-like metal portions (pieces) where the island-like metal portion, observed in cross-section of the composite Each of the island-shaped portions of the impregnated metal distributed in the shape of an island surrounded by the network skeleton structure of the ceramic sintered body is referred to, and the “area of the metal phase” is the sum of the areas of the island-shaped metal portions. . The observation field of view is
The area is 1.0 mm ² or more. ] 2. The metal ceramic composite according to claim 1, wherein the porous ceramic sintered body is a sintered body formed by a recrystallization sintering method. 3. The ceramic is made of silicon carbide, silicon nitride,
The metal-ceramic composite according to claim 2, comprising one or more selected from aluminum nitride and alumina, and the impregnated metal is a metal containing aluminum, copper or magnesium as a main component. 4. A metal ceramic composite according to claim 3, wherein nickel plating is applied to at least a region of the plate surface on which the insulating substrate for mounting a semiconductor element is mounted, on which the insulating substrate is mounted. Heat dissipating member for electronic devices. 5. The metal-ceramic composite according to claim 3, wherein at least a region of the plate surface on which the insulating substrate for mounting a semiconductor element is mounted on which the insulating substrate is mounted is made of the same metal as the impregnated metal. Heat dissipating member for an electronic element on which a metal layer is formed. 6. The heat-dissipating member for an electronic element according to claim 5, wherein the heat-dissipating member for an electronic element has a portion where the plate surface of the metal-ceramic composite is exposed in a region other than the insulating substrate mounting region. 7. The heat radiating member for an electronic element according to claim 5, wherein a nickel plating is applied to a surface of the metal layer on which the insulating substrate is mounted. 8. The metal-ceramic composite has a metal layer made of the same metal as the impregnated metal and heat-radiating fins protruding from the metal layer formed on the plate surface opposite to the plate surface on which the insulating substrate is mounted. The heat dissipating member for an electronic element according to claim 4, wherein 9. The metal-ceramic composite is 0.75 c
The thermal diffusivity of m < ² > / sec or more, the thermal conductivity of 180 W / m * K or more, and the thermal expansion coefficient of 7.5 * 10 < ^-6 > / K or less, The thermal expansion coefficient of any one of Claims 4-8. Heat dissipating member for electronic devices.