JPH1158596A - Cemented body composed of metallic base and ceramic base - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cemented body composed of a metallic base and a ceramic base, which are laminated through an adhesive, and has an excellent thermal conductivity without being affected by warpage or winding of the cemented base. SOLUTION: A cemented body A is formed by laminating a metallic base 1 and a ceramic base 2 through an adhesive 3, where at least on either of the metallic base 1 or the ceramic base 2, a metallic heat transfer body 5 capable of deforming by external pressure is cemented directly. The metallic heat transfer body 5 is arranged between the metallic base 1 and the ceramic base 2. Thereby thermal conductivity between the metallic base 1 and the ceramic base 2 is improved. By applying pressure beforehand to the sides opposite to the sides of the other bases 1 or 2 of the metallic heat transfer. body 5 directly cemented to either of the bases 1 or 2, the shape of the metallic heat transfer body 5 can easily follow the shape of the other bases 1 or 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joined body of a metal substrate and a ceramic substrate which require heat radiation.

[0002]

2. Description of the Related Art In recent years, a technique of combining a metal base material and a ceramic base material by bonding or the like has been increasingly developed. In particular, in a ceramic wiring board, heat generated from a heat-generating component such as a power IC is efficiently radiated. Therefore, it is used as a technique for joining a metal base material as a heat radiating plate to a ceramic wiring board, and is an indispensable technique for integration of semiconductor elements.

[0003] As a simplest method for obtaining a bonded body of a metal substrate and a ceramic substrate, a method of bonding between the substrates by using an adhesive has conventionally been used. Is selected as appropriate. For example,
If the difference in the coefficient of thermal expansion between the metal substrate and the ceramic substrate to be joined is large, modified epoxy-based, urethane-based,
A flexible adhesive such as silicone is used, and for the purpose of improving the thermal conductivity between the substrates to be joined, for example, silver, copper, aluminum nitride, silicon carbide, etc. Adhesives containing mixed particles (thermally conductive fillers) are selected.

[0004]

However, in recent years, it has been required to further reduce the thermal resistance of a joined body of a metal base material and a ceramic base material. Things have become difficult.

[0005] This is because even if an attempt is made to reduce the thermal resistance by making the thickness of the adhesive thin and joining, the ceramic base material and the metal base material to be joined have warpage or undulation, so that the air at the joining interface is formed. This is because a layer is formed and conduction of heat is interrupted in this air layer.

The present invention has been made in view of the above points, and has been made in view of the above circumstances. A metal base and a ceramic base capable of improving thermal conductivity without being affected by warpage or undulation between the metal base and the ceramic base. It is an object of the present invention to provide a joined body of materials.

[0007]

According to a first aspect of the present invention, there is provided a bonded body A in which a metal base 1 and a ceramic base 2 are bonded together with an adhesive 3 therebetween. A metal heat transfer member 5 that can be deformed by an external pressure is directly joined to at least one of them, and the metal heat transfer member 5 is disposed between the metal base 1 and the ceramic base 2. It is assumed that.

According to a second aspect of the present invention, the metal heat transfer member 5 is heated by the metal base material 1 and the ceramic base material 2 while the metal heat transfer member 5 is heated to a temperature not lower than the melting point of the metal heat transfer member 5. By sandwiching and pressing, the metal heat transfer body 5 is directly joined to at least one of the metal base and the one ceramic base 2.

Further, the invention according to claim 3 is characterized in that the metal heat conductor 5 has a melting point lower than those of the metal base 1 and the ceramic base 2.

The invention according to claim 4 is characterized in that the metal heat conductors 5 are arranged discretely between the metal substrate 1 and the ceramic substrate 2.

The invention according to claim 5 is characterized in that the metal heat conductor 5 is formed as a projection.

The invention according to claim 6 is characterized in that the metal heat conductor 5 is a solder material.

According to a seventh aspect of the present invention, the surface facing the metal substrate 1 is made of a metallized ceramic substrate 2.

The invention of claim 8 is characterized in that a spacer 8 is interposed between the metal base 1 and the ceramic base 2.

According to a ninth aspect of the present invention, the ceramic substrate 2
And the occupation density of the metal heat transfer bodies 5 disposed on the back surface of the mounting position of the heat-generating component 9 on the ceramic wiring board 2a and the vicinity thereof is occupied by the metal heat transfer bodies 5 in other portions. It is characterized by being higher than the density.

According to a tenth aspect of the present invention, a ceramic wiring board 2a is used as the ceramic substrate 2, and a metal wiring disposed on the back surface of a portion where wire bonding is performed on the wiring 11 of the ceramic wiring board 2a and in the vicinity thereof. The occupation density of the heat element 5 is higher than the occupation density of the metal heat transfer element 5 in other portions.

[0017]

Embodiments of the present invention will be described below.

FIGS. 1A to 1E show an embodiment of the present invention. FIGS. 1A to 1E
As shown in (1), the joined body A of the metal base material 1 and the ceramic base material 2 according to the present invention is manufactured by bonding the metal base material 1 and the ceramic base material 2 with the adhesive 3 interposed therebetween. Things. Metal substrate 1 and ceramic substrate 2
At least one of the metal heat transfer bodies 5 that is deformable by an external pressure is directly bonded to the metal heat transfer body 5 that is directly connected to at least one of the base materials 1 as described above. 1 and a ceramic substrate 2. Therefore, the heat conductivity at the bonding interface between the metal base 1 and the ceramic base 2 is improved by the metal heat transfer body 5 directly bonded to the bases 1 and 2, and the metal base 1 of the bonded body A and the ceramic base The heat conductivity between the materials 2 can be improved.

Here, the term "direct bonding" means, for example, a plating method, a solder / brazing material bonding method, a sputtering method, an ion plating method, a thick film paste method, a metal diffusion bonding method or the like without using an adhesive or the like. It means that the metal heat transfer member 5 is metallurgically or chemically bonded to the surface of the metal substrate 1 or the ceramic substrate 2.

Here, FIG. 1A shows an example in which a metal heat transfer body 5 is directly and entirely joined to a metal substrate 1, and FIG.
FIG. 1C shows an example in which a metal heat transfer element 5 is directly and entirely joined to a ceramic base material 2. FIG. Figure 1 shows an example of bonding.
(D) shows an example in which a plurality of metal heat conductors 5 formed in the shape of protrusions on the ceramic base material 2 are discretely directly joined.
FIG. 1E shows an example in which a plurality of metal heat conductors 5 formed in the shape of protrusions are directly and discretely joined to a metal substrate 1 and a ceramic substrate 2.

The metal substrate 1 used for the joined body A according to the present invention is appropriately selected according to the required quality, cost, and the like. The ceramic substrate 2 is also oxide-based, nitride-based, and carbide-based. The system type is appropriately selected.

The adhesive 3 is arbitrarily selected according to the purpose of use of the joined body A. When importance is attached to the improvement of the heat conductivity, a material containing a heat conductive filler is used.
In the case where the mechanical strength of the layer 4 of the adhesive 3 is emphasized and the joined body A is easily bent, a urethane-based or silicone-based material is used. If fire resistance is required,
A polyimide-based material can be used.

In the heat cycle, the substrate 1,
The bonding between the substrates 1 and 2 and the layer 4 of the adhesive 3 is prevented from being dissociated by the stress applied between the substrates 1 and 2 and the layer 4 of the adhesive 3 caused by the difference in the coefficient of thermal expansion between the two. When importance is placed on the degree of mechanical freedom of the layer 4 of the adhesive 3 for the purpose of, for example, the rubber hardness of the adhesive 3 is preferably set to 70 or less.

The material of the metal heat conductor 5 is not particularly limited as long as it can be deformed by external pressure, but a metal which can be expected to have a thermal conductivity at least one order of magnitude higher than that of the adhesive 3 to be used is preferable.

Examples of the metal heat transfer element 5 which can be easily deformed by external pressure include In and its alloys, and various metal wires are also suitable as a material for imparting flexibility. In addition, a brazing material or a solder material that can be easily subjected to external pressure deformation by applying heat can also be used. In particular, a solder material containing Sn as a main component can be obtained at low cost, and at the same time, has a relatively low melting point. This is preferable in manufacturing.

In the case where a solder material having a relatively low melting point is used as the metal heat transfer body 5 and the metal heat transfer body 5 is directly joined to the ceramic base material 2 side, the ceramic base material 2 If the surface of is metallized in advance by a suitable method such as the plating method and the sputtering method described above to form a metal film, the metal heat transfer body 5 can be easily directly joined to the ceramic base material 2. Therefore, it is preferable.

A metal heat transfer member 5 directly joined to one of the metal base 1 and the ceramic base 2, 2.
It is preferable that the surface of the substrate 1 that is directly bonded to the other base materials 1 and 2 via the adhesive 3 or is flattened in advance.

Here, the term “flattening” refers to the other substrates 1, 2
Refers to applying external pressure to the surface to be joined to form a shape following the shape of the other base material 1 or 2, and the height when the metal heat transfer body 5 is directly joined to the base material 1 or 2. Correction of variations,
This is effective when the substrates 1 and 2 have warpage or undulation.

In general, when the substrates 1 and 2 having warpage and undulation are overlapped with each other, a portion where the gap between the substrates 1 and 2 is partially wide occurs. Therefore, when the metal heat transfer member 5 and the other base materials 1 and 2 are to be directly joined, the metal heat transfer member 5 is located at a position where the gap between the base materials 1 and 2 is wide. In such a case, a gap is formed between the base material 1 and the base material 2, and as a result, the thermal conductivity of the joined body A may be partially deteriorated.

Therefore, when the metal heat transfer member 5 is flattened as described above, the metal heat transfer member 5 and the other base materials 1 and 2 can be directly connected at all locations. The gap in which the adhesive 3 is interposed between the metal heat transfer body 5 and the other substrates 1 and 2 can be made uniform, and the variation in the thermal conductivity of the joined body A can be reduced.

In particular, if a material that liquefies at a relatively low temperature, such as a solder material as described above, or a material that is easily deformed by external pressure, such as an In-based or various metal wires, is used as the metal heat conductor 5, warpage or warpage may occur. The shape of the metal heat transfer element 5 can easily follow the undulating substrates 1 and 2, the metal heat transfer element 5 can be easily flattened, and the variation of the thermal conductivity can be reduced. It is effective for

Further, the metal heat transfer member 5 can be flattened by using the metal base material 1 and the ceramic base material 2 constituting the joined body A. That is, the metal heat transfer body 5 is used for the one base material 1,
After being directly bonded to the second heat transfer member 5, the surface of one of the base materials 1 and 2 on which the metal heat transfer member 5 is formed and the other base material 1 and 2 are overlapped with each other and pressurized. The shape is made to follow the shape of the other substrates 1 and 2, and then the two substrates are joined directly or via an adhesive. In this way, even if any warpage or undulation exists in both base materials 1 and 2,
The metal heat transfer element 5 can be reliably flattened, and the metal heat transfer element 5 can be directly and reliably bonded to all of the other bases 1 and 2 or the metal heat transfer element The body 5 can be joined to the other base material 1 or 2 by ensuring that the gap in which the adhesive 3 is interposed is uniform. Further, by applying a load between the base materials 1 and 2 and applying heat to melt the metal heat transfer body 5, the shape of the metal heat transfer body 5 follows the shape of the other base materials 1 and 2 and is flattened. In this case, the metal heat transfer element 5 is flattened, and at the same time, the metal heat transfer element 5 directly connected to one of the substrates 1 and 2 is directly connected to the other one or two. can do. In this case, the metal base 1 and the ceramic base 2 are not melted at the time of heating. It is preferable to use one having a low melting point.

When a solder material is used as the metal heat conductor 5, although there is no particular limitation on the solder material, for example, the ceramic substrate 2 of the joined body A is used as the ceramic wiring board 2a, and the components are mounted on the surface thereof. Is performed, it is preferable to use a solder material having a melting point higher than the component connection temperature. In this case, the ceramic wiring board 2a
The connection of the above mounted components can be performed by heating to a temperature at which the joining between the substrates 1 and 2 is not impaired. The adhesive 3 used when applying a load and applying heat when joining the base materials 1 and 2 using a solder material as the metal heat transfer material 5 has heat resistance like a silicone adhesive. Choose the best one.

In the case where the metal heat transfer member 5 is flattened as described above, or an external force is applied between the base materials 1 and 2 when the base materials 1 and 2 are joined using the adhesive 3,
The metal heat transfer body 5 and the adhesive 3 may protrude outside from between the base materials 1 and 2. Therefore, as shown in FIG.
Between the two, an appropriate number of spacers 8 that maintain the thickness between the substrates 1 and 2 at an appropriate thickness can be arranged. In this case, since the thickness between the bases 1 and 2 is regulated by the spacer 8, the bases 1 and 2 are connected to each other via the metal heat transfer body 5 or via the metal heat transfer body 5 and the adhesive 3. Even if pressure is applied, the distance between the substrates 1 and 2 will not be too narrow, and therefore, the metal heat transfer material 5 and the adhesive 3 will not protrude outside from the gap between the substrates 1 and 2. Is what you can do.

As described above, the joined body A of the metal base 1 and the ceramic base 2 shown in FIGS. 1A to 1E is formed. 1 (a) and 1 (b), the metal heat exchanger 5 is formed in a layer, and this layered metal heat exchanger 5 is directly joined to the entire surface of one of the substrates 1 and 2. At the same time, it is bonded to the other base materials 1 and 2 via the layer 4 of the adhesive 3, and the thermal conductivity is increased by the metal heat conductor 5 over the entire surface of the bonded body A. This is a structure suitable for improving conductivity.

In FIGS. 1 (c) and 1 (d), a plurality of metal heat conductors 5 are discretely arranged between the substrates 1 and 2, and the metal And bonded to the other substrates 1 and 2 via an adhesive 3.
Here, the term “discretely arranged” means that a plurality of metal heat conductors 5 are arranged at intervals along a gap between the metal substrate 1 and the ceramic substrate 2, and the adjacent metal heat conductors 5 are arranged. 5
The adhesive 3 is interposed between them. This figure 1
In (c) and (d), the difference in the coefficient of thermal expansion between the two substrates 1 and 2 is large, and when the joined body A is heated, the distance between the metal substrate 1 and the ceramic substrate 2 is increased. Even if stress is applied between the two substrates 1 and 2 due to the difference in thermal expansion coefficient, even if stress is applied between the metal heat transfer bodies 5,
In addition, stress can be absorbed by elastic deformation of the adhesive 3 interposed between the metal heat transfer body 5 and the metal base 1 or the ceramic base, and the metal heat transfer body 5 and both the bases 1 and 2 can absorb the stress. The concentration of stress on the bonding interface between the base material 1 and the metal heat transfer material 5 is reduced.
Can be prevented from being dissociated. In particular, FIG. 1 using a metal heat transfer body 5 formed as a protrusion with a smaller cross-sectional area than that of the metal heat transfer body 5 shown in FIG.
In the case shown in (d), the effect of relieving the concentration of stress on the bonding interface between the metal heat transfer body 5 and the two substrates 1 and 2 is high, and the size of the bonded body A is large, so that the influence of the stress is high. Even in such a case, it is possible to prevent the bonding between the base materials 1 and 2 and the metal heat conductor 5 from being dissociated.

In FIG. 1E, a plurality of metal heat transfer bodies 5 formed as protrusions are discretely arranged between the metal base 1 and the ceramic base 2, and This metal heat transfer body 5 is directly bonded to both the metal substrate 1 and the ceramic substrate 2, and therefore, the effect of relaxing the stress at the bonding interface is shown in FIGS. 1 (c) and 1 (d). Although the material is higher, since the adhesive 3 is not interposed between the metal heat conductor 5 and the two substrates 1 and 2, the heat conductivity of the joined body A is extremely excellent. can do.

Here, when the metal heat transfer elements 5 are arranged discretely or formed into a projection, the shape of the metal heat transfer elements 5 is not particularly specified, and may be layered, spherical, Various shapes such as a columnar shape and a needle shape can be used. Although the dimensions are not particularly specified, they are about several tens μm to several cm square or several tens μm to several mm in diameter, and the height or the thickness of the two It is preferable to use a material having a size of a gap caused by warpage or undulation of the materials 1 and 2.

As described above, the joined body A of the metal substrate 1 and the ceramic substrate 2 of the present invention has the metal heat transfer member 5 that can be deformed following the warpage or undulation of the substrates 1 and 2. Therefore, the thermal conductivity can be made superior to that of a conventional bonded body bonded only with an adhesive containing a thermally conductive filler.

FIGS. 3 to 6 show specific application examples of the joined body A of the metal substrate 1 and the ceramic substrate 2 according to the present invention.

FIG. 3 shows a case where the ceramic substrate 2 of the joined body A is used as a ceramic wiring board 2a. Wiring 11 is formed on one surface of the ceramic substrate 2, and a plurality of protrusion-shaped metal heat conductors 5 are uniformly arranged and a plurality of spacers 8 are arranged on the other surface. It is bonded to the metal substrate 1 through the layer 4 of the adhesive 3. On the wiring 11, a heat generating component 9 such as a power IC is mounted at a predetermined position.

In the joined body A thus formed,
When a circuit formed on the ceramic wiring board 2a is driven, heat is generated from the heat-generating component 9, but the joined body A is formed by the metal heat transfer body 5 disposed between the metal base 1 and the ceramic base 2. Since the thermal conductivity is increased, the heat generating component 9
Can be quickly radiated from the ceramic substrate 2 to the metal substrate 2 side.

FIG. 4 is a perspective view of the structure shown in FIG. 3, and shows a protruding metal heat transfer member disposed on the adhesive and the layer 4 of the adhesive 3 on the back surface of the mounting position of the heat-generating component 9 and in the vicinity thereof. 5 is higher than the occupation density of the metal heat conductor 5 in other portions, and therefore, the joined body A
The thermal conductivity of the heating component 9 at the mounting position of the heating component 9 and its vicinity is
It can be higher than other parts.

In the joined body A thus formed,
When the circuit formed on the ceramic wiring board 2a is driven, heat is generated from the heat-generating component 9, and the heat causes the mounting position of the heat-generating component 9 of the bonded body A to be intensively heated.
Since the thermal conductivity of the joined body A is higher at the mounting position of the heat-generating component 9 and in the vicinity thereof than at the other portions, the heat generated from the heat-generating component 9 causes the mounting position of the heat-generating component 9 in the joined body A and In the vicinity, heat is quickly and efficiently dissipated.

FIG. 5 shows that the ceramic substrate 2 of the joined body A is used as a ceramic wiring board 2a, similar to the one shown in FIGS. The wiring 11 is formed, and the other surface is joined to the metal base 1 through the layer 4 of the adhesive 3 on which the plurality of protruding metal heat conductors 5 and the spacers 8 are arranged, The heat-generating component 9 is mounted on the wiring 11 at a predetermined position by a bare chip. Further, in the one shown in FIG.
The wiring (not shown) on the heat generating component 9 and the wiring 11 on the ceramic wiring board 2a are connected to a wire 9 such as an aluminum wire.
are connected by a.

Here, on the back surface of the mounting position of the heat-generating component 9 and its vicinity, and on the back surface of the connection position with the wire 9a on the wiring 11 and its vicinity, the protrusions arranged on the layer 4 of the adhesive 3 The occupation density of the metal heat transfer bodies 5 in the shape of a circle is higher than the occupation density of the metal heat transfer bodies 5 in other portions.

In the joined body A thus formed,
When the circuit formed on the ceramic wiring board 2a is driven, heat is generated from the heat-generating component 9, and the mounting position of the heat-generating component 9 is intensively heated. Since the mounting position of the heat generating component 9 and its vicinity are higher than other parts, the heat generated from the heat generating component 9 is quickly radiated at the mounting position of the heat generating component 9 in the joined body A and its vicinity. Things.

In performing the wire bonding between the wiring 11 and the wire 9a, it is determined that the ultrasonic wave emitted from the wire bonder for performing the wire bonding by the ultrasonic wave is absorbed by the layer 4 of the adhesive 3 to cause the bonding failure. Metal heat transfer body 5 arranged at a high occupancy density on the back surface of the wire bonding position on and near 11
Can be prevented.

FIG. 6 shows a wiring 1 in addition to the configuration shown in FIG.
1, a lead frame 10 made of copper or the like at a desired position,
As in the case of joining the metal base 1 and the ceramic base 2 shown in FIG.
And the lead frame 10 were directly joined, the layer 4 of the adhesive 3 was formed so as to cover the metal heat transfer member 5, and the spacers 8 were interposed between the wiring 11 and the lead frame. Things.

In the application example shown in FIG. 6, the thickness of the ceramic wiring board 2a at an arbitrary position on the wiring 11 can be increased by bonding the lead frame 10 by a simple bonding process. A large current circuit that requires a thickness and a control circuit that requires a thin wiring thickness for forming fine wiring can easily coexist on one wiring board.

[0051]

The present invention will be described below in detail with reference to examples.

Example 1 (1) A Cu—W alloy substrate having a thickness of 2 mm was prepared as a metal substrate 1 and plated with Ni having a thickness of 3 μm. An alumina substrate having a thickness of 1 mm was prepared as the ceramic substrate 2. (2) In-Pb cream solder (manufactured by Indium Corporation) is applied to the entire surface of one surface of the metal substrate 1 by printing, and reflow and flux cleaning are performed to obtain a thickness of about 1
A 50 μm layered metal heat conductor 5 was formed. (3) Silicone adhesive 3 containing a thermally conductive filler (manufactured by Toshiba Silicone Co., Ltd., “TSE3280-
G ”) with a thickness of 200 μm, and then the ceramic substrate 2 is superimposed on the metal heat transfer member 5 to be 10 kg / cm.
^By pressing with a pressing force of ² , the surface of the metal heat transfer body 5 on the ceramic base 2 side is flattened, and the metal base 1 and the ceramic base 2 are interposed with the metal heat transfer body 5 and the adhesive 3 interposed therebetween. Thus, a joined body A having a structure shown in FIG. 1A was obtained. (Example 2) (1) Same as Example 1 (2) Sn-Cu cream solder (manufactured by Nippon Superior Co., Ltd.) was applied on the entire surface of one surface of the metal substrate 1 by printing.
By performing reflow and flux cleaning at 50 ° C., a layered metal heat conductor 5 having a thickness of about 150 μm was formed.

Further, after the ceramic base material 2 is superimposed on the layered metal heat transfer body 5 formed on the metal base material 1,
Reflow was performed at 0 ° C. to flatten the surface of the metal heat transfer body 5 on the ceramic substrate 2 side. (3) Silicone adhesive 3 containing a thermally conductive filler (manufactured by Toshiba Silicone Co., Ltd., “TSE3280-
G ”) with a thickness of 200 μm, and then the ceramic substrate 2 is superimposed on the metal heat transfer member 5 to be 10 kg / cm.
^By pressing at a pressing force of ² and heating and curing at 150 ° C. for 1 hour, the metal base 1 and the ceramic base 2 are joined with the metal heat transfer material 5 and the adhesive 3 interposed therebetween, A joined body A having the structure shown in FIG. 1A was obtained. (Example 3) (1) Same as in Example 1 (2) Cu paste (“2312-A”, manufactured by ESL) on the entire surface of one surface of the ceramic substrate 2 by a thick film printing method.
After the formation of the metallized layer by
A layered metal heat conductor 5 made of n-Pb was formed, and the metal heat conductor 5 was flattened. (3) Same as in the first embodiment. (Example 4) (1) Same as Example 1 (2) Cu paste (“2312-A”, manufactured by ESL) on the entire surface of one surface of the ceramic substrate 2 by a thick film printing method.
After the formation of the metallized layer by S
A layered metal heat conductor 5 made of n-Cu was formed, and the metal heat conductor 5 was flattened. (3) Same as in the first embodiment. (Comparative Example 1) (1) Same as in Example 1 (2) The metal heat conductor 5 was not formed on any of the metal base 1 and the ceramic base 2. (3) Silicone adhesive 3 containing a thermally conductive filler over the entire surface of one surface of metal substrate 1 (Toshiba Silicone Co., Ltd.)
Co., Ltd., “TSE3280-G”) is applied at a thickness of 200 μm, and the ceramic substrate 2 is superimposed on the metal heat conductor 5 and pressed at a pressure of 10 kg / cm ² , and at 150 ° C. for 1 hour. By heating and thermosetting, the metal base 1 and the ceramic base 2 were bonded together with the metal heat transfer member 5 and the adhesive 3 interposed therebetween to obtain a bonded body.

Table 1 shows the results of measuring the thermal resistance of each of the joined bodies of Examples 1 to 4 and Comparative Example 1.
Comparative Example 1 is shown as 100.

[0055]

[Table 1] As can be seen from Table 1, the thermal resistances of Examples 1 to 4 are sufficiently smaller than those of Comparative Example 1, and the heat resistance obtained by disposing the layered metal heat conductor 5 between the substrates 1 and 2 The effect of reducing the thermal resistance by directly bonding to the substrates 1 and 2 was confirmed. (Example 5) An aluminum substrate having a thickness of 2 mm was prepared as the metal substrate 1, and an alumina substrate having a thickness of 1 mm was prepared as the ceramic substrate 2. (2) After roughening the surface of the ceramic base material 2 using hot phosphoric acid treatment, applying electroless copper plating with a thickness of 10 μm and electroless Ni plating with a thickness of 3 μm to the entire surface, and metallizing in advance, Sn-
Ag-based cream solder (Nippon Superior Co., Ltd., “Sn9
6)), and a plurality of metal heat conductors 5 having a size of 2 × 2 × 0.1 mmt were discretely formed on the entire surface of one surface of the ceramic substrate 2 at intervals of 2 mm.

Next, after the metal heat transfer member 5 is once melted and solidified at a temperature of 250 ° C. in a reflow furnace, the metal substrate 1 is superposed on the surface of the ceramic base member 2 on which the metal heat transfer member 5 is formed. Then, reflow was performed at a temperature of 250 ° C., and the tip of the metal heat transfer body 5 was flattened by the weight of the metal substrate. (3) A silicone adhesive 3 containing a thermally conductive filler is provided on the surface of the ceramic
(“TSE3280-G” manufactured by Toshiba Silicone Co., Ltd.)
Is applied thereon, and the metal substrate 1 is superposed and adhered thereon, and a layer 4 of the adhesive 3 having a thickness of 100 μm is formed.
It was cured by heating at a temperature of 50 ° C. for 1 hour to obtain a joined body A having a configuration shown in FIG. 1C. (Example 6) (1) Same as Example 5 (2) In-Pb cream solder (manufactured by Indium Corporation) is printed and applied to the entire surface of the ceramic substrate 2, and is applied to the entire surface of the ceramic substrate 2. Example 5 was carried out in the same manner as in Example 5, except that a plurality of metal heat conductors 5 having a size of 2 x 2 x 0.1 mmt were discretely formed at intervals of 2 mm. (3) Same as Example 5 (Example 7) (1) Same as Example 5 except that aluminum nitride was used as the ceramic substrate. (2) Ag-Pb paste (manufactured by ESL, “960”) is applied to the entire surface of the ceramic substrate 2 by the thick film printing method.
1)), except that the metallization according to 1) was previously formed. (3) Same as Example 5. (Example 8) (1) Same as Example 5, (2) In-Pb cream solder Indium Corporation, except that the metal heat conductor 5 was formed by a sputtering method using masking. Same as 6. (3) Same as Example 5. Example 9 (1) Same as Example 7. (2) Same as Example 8 except that copper was previously metallized on the entire surface of the ceramic substrate 2 by sputtering. (Example 10) (1) Same as Example 5. (2) The surface of the ceramic base material 2 is roughened using hot phosphoric acid, and electroless copper plating with a thickness of 10 μm and electroless Ni plating with a thickness of 3 μm are applied to predetermined locations. An Al-Si wire (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) was crimped to the surface using a wire bonding method to form a plurality of metal heat conductors 5 having a height of 0.1 mm. Here, the area occupied by the metal heat transfer element 5 on the ceramic base material was set to be equal to the area occupied by the metal heat transfer element 5 in Example 5. (3) A silicone adhesive 3 containing a thermally conductive filler (manufactured by Toshiba Silicone Co., Ltd.) is provided on the entire surface of the ceramic base 2 on which the wire-shaped metal heat conductor 5 is formed.
After applying “TSE3280-G”) with a thickness of 200 μm, the metal substrate 1
By pressing with a pressing force of kg / cm ² , the tip of the metal heat transfer body 5 on the side of the metal base 1 is flattened, and the metal base 1 and the ceramic base 2 are separated by the metal heat transfer body 5 and the adhesive 3. To form a joined body A. (Example 11) (1) Same as Example 7. (2) Same as Example 10 (3) Same as Example 10 (Example 12) (1) Same as Example 5 except that a silicon carbide substrate having a thickness of 1 mm was used as the ceramic substrate 2. (2) Same as Example 10. (3) Same as Example 10. (Comparative Example 2) (1) Same as Example 5. (2) The metal heat conductor 5 was not formed on any of the metal substrate 1 and the ceramic substrate 2. (3) The ceramic base material 2 and the metal base material 1 are directly bonded using a silicone adhesive 3 containing a thermally conductive filler (“TSE3281-G” manufactured by Toshiba Silicone Co., Ltd.), and a 100 μm-thick bonding. Form a layer of agent,
A conjugate was obtained.

Table 2 shows the thermal resistance of each of the joined bodies of Examples 5 to 12 and Comparative Example 2.
As shown.

[0058]

[Table 2] As can be seen from Table 2, the thermal resistance of Examples 5 to 12 is about 1/2 that of Comparative Example 2, despite the use of an adhesive having good thermal conductivity in Comparative Example 2. The effect of reducing the thermal resistance by discretely directly joining the metal heat conductors 5 to the materials 1 and 2 was confirmed.

Example 13 (1) An aluminum substrate having a thickness of 2 mm was prepared as the metal substrate 1, and the surface thereof was plated with Zn 0.1 μm thick and Ni 2 μm thick.

The ceramic substrate 2 has a thickness of 1 mm.
Was prepared. (2) A photo-solder resist is formed on one surface of the metal substrate 1, a predetermined portion of the resist is removed by exposure and development, and the N on the metal substrate 1 exposed at the removed portion is removed.
One surface of the metal substrate 1 is formed by applying a Sn-Ag-based cream solder (“Sn96”, manufactured by Nippon Superior Co., Ltd.) on the surface of the i-plated layer by screen printing, and then melting and solidifying the cream solder at 260 ° C. through a reflow furnace. A metal heat conductor 5 having a dimension of 2 × 2 × 0.1 mm was formed on the entire surface at intervals of 2 mm, and then the solder resist was alkali-removed. (3) Silicone adhesive containing thermal conductive filler 3
(“TSE3280-G” manufactured by Toshiba Silicone Co., Ltd.)
Is applied to the surface of the metal substrate 1 on which the metal heat transfer body 5 is formed, and the ceramic substrate 2 is overlaid thereon and the layer 4 of the adhesive 3 having a thickness of 100 μm is formed.
A joined body A having the structure shown in (d) was obtained. Comparative Example 3 (1) Same as Example 13. (2) The metal heat conductor 5 was not formed on any of the metal substrate 1 and the ceramic substrate 2. (3) The ceramic substrate 2 and the metal substrate 1 are directly bonded to each other by using a silicone adhesive 3 containing a thermally conductive filler (“TSE3280-G” manufactured by Toshiba Silicone Co., Ltd.) and an adhesive having a thickness of 100 μm. The layer 4 of No. 3 was formed to obtain a joined body.

Table 3 shows the results of measuring the respective thermal resistances of the joined bodies of Example 13 and Comparative Example 3 as 100 for Comparative Example 3.

[0062]

[Table 3] As can be seen from Table 3, the thermal resistance of Example 13 was lower than that of Comparative Example 3.
Despite the use of an adhesive having good thermal conductivity in Comparative Example 3, it is about の of that of Comparative Example 3, and the protrusion-shaped metal heat conductors 5 are directly and discretely joined to the substrates 1 and 2. Thus, the effect of reducing the thermal resistance was confirmed. (Example 14) (1) Same as in Example 13 (2) The metal heat conductor 5 is formed on the metal substrate 1 by the method of Example 13, and the metal is also applied to the ceramic substrate 2 by the method of Example 8. The heat transfer body 5 was formed. Here, the total area occupied by the metal heat transfer bodies 5 formed on the base materials 1 and 2 on the base materials 1 and 2 was made equal to the area occupied by the metal heat transfer bodies 5 in Example 5. . (3) Silicone adhesive containing thermal conductive filler 3
(“TSE3280-G” manufactured by Toshiba Silicone Co., Ltd.)
Is applied to the surfaces of the metal base material 1 and the ceramic base material 2 on which the metal heat transfer bodies 5 are formed, and the surfaces of the base materials 1 and 2 on which the metal heat transfer bodies 5 are formed are overlapped with each other. After forming a layer 4 of the adhesive 3 having a thickness of 100 μm, FIG.
1 (d) was obtained.

Table 4 shows the thermal resistance of the joined body A in Example 14 as 100 in Comparative Example 3.

[0064]

[Table 4] As can be seen from Table 4, the thermal resistance of Example 14 was equal to that of Comparative Example 3.
Is about half that of Comparative Example 3 despite the use of an adhesive having good thermal conductivity, and the thermal resistance caused by discretely directly joining the metal heat conductors 5 to the substrates 1 and 2 The effect of the reduction was confirmed.

(Embodiment 15) (1) Same as Embodiment 1. (2) A Ti-based brazing material ("TKC641", manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) is disposed at a predetermined position on the ceramic base material 2 and melted by heating at 850 ° C. to directly join the ceramic base material. 2 on the entire surface of material 2 at 2 mm intervals
A metal heat transfer body 5 having dimensions of × 2 × 0.1 mm was formed. (3) The metal substrate 5 is flattened by superimposing the ceramic substrate 2 on which the above-described metal heat transfer member 5 is directly bonded and heat-treating the metal substrate 1 at 800 ° C. The tip 7 of the metal heat transfer body 5 is also directly joined to one side,
Thereafter, the gap between the base materials 1 and 2 is filled with a urethane-based adhesive 3 (manufactured by Asahi Chemical Laboratory Co., Ltd.) to a thickness of 10
A layer 4 of the adhesive 3 having a thickness of 0 μm was formed to obtain a joined body A having a structure shown in FIG. (Example 16) (1) Same as Example 1. (2) Same as Example 6. (3) The adhesive 3 is a urethane-based adhesive 3 (Co., Ltd.)
The same as Example 15 except that Asahi Chemical Laboratory was used. (Example 17) (1) Same as Example 1. (2) Same as Example 6. (3) Same as Example 15 except that a polyimide-based adhesive 3 (Ube Industries, Ltd.) was used as the adhesive 3. (Comparative Example 4) (1) Same as Example 1. (2) The metal heat conductor 5 was not formed on any of the metal substrate 1 and the ceramic substrate 2. (3) The ceramic substrate 2 and the metal substrate 1 are directly bonded to each other by using a silicone adhesive 3 containing a thermally conductive filler (“TSE3280-G” manufactured by Toshiba Silicone Co., Ltd.) and an adhesive having a thickness of 100 μm. The layer 4 of No. 3 was formed to obtain a joined body.

Table 5 shows Examples 15 to 17 and Comparative Example 4.
The result of measuring the thermal resistance of each of the joined bodies of Comparative Example 4 is shown as 100 for Comparative Example 4.

[0067]

[Table 5] As can be seen from Table 5, despite the use of an adhesive having good thermal conductivity in Comparative Example 3, the thermal resistance of Examples 15 to 17 was about 1/2 that of Comparative Example 4, The effect of reducing the thermal resistance by directly joining the metal heat conductor 5 to the base materials 1 and 2 was confirmed.

Example 18 (1) Same as Example 5. (2) The surface of the ceramic substrate 2 was roughened using hot phosphoric acid, and electroless copper plating with a thickness of 10 μm and electroless Ni plating with a thickness of 3 μm were applied to the entire surface and metallized in advance. An Ag-based cream solder (“Sn96” manufactured by Nippon Superior Co., Ltd.) is applied by printing, and the entire surface of the ceramic substrate 2 is 2 × 2 × 0.1 m thick at 2 mm intervals.
A metal heat conductor 5 having a size of m was formed. (3) A silicone adhesive 3 containing a thermally conductive filler is provided on the surface of the ceramic
(“TSE3280-G” manufactured by Toshiba Silicone Co., Ltd.)
Is applied, and the metal substrate 1 is superimposed thereon, and 250
C. and pressurized at a pressure of 50 kg / cm ² for 5 minutes to melt and flatten the metal heat conductor 5.
The adhesive 3 is cured by heating at 50 ° C. for one hour,
Then, a layer 4 of the adhesive 3 was formed to obtain a joined body A having a configuration shown in FIG.

Table 6 shows the results of measurement of the thermal resistance of the joined body A of Example 18 assuming that the value of Comparative Example 2 is 100.

[0070]

[Table 6] As can be seen from Table 6, the heat resistance of Example 18 in which pressing was performed at the time of curing the adhesive 3 was smaller than that of Example 5, and the metal heat conductor 5 was formed of a solder material. It was confirmed that the effect of reducing the thermal resistance by reducing the gap between the front end and the substrates 1 and 2 facing the front end was narrowed.

(Embodiment 19) (1) Same as Embodiment 1. (2) Same as Example 18. (3) When the two substrates 1 and 2 are overlapped, a thickness of 100
μm chips are used as spacers 8 for both substrates 1
Same as Example 18 except that it was sandwiched between the two.

Table 7 shows the results of measuring the thermal resistance of the joined body A of Example 19, with the result of Comparative Example 2 taken as 100.

[0073]

[Table 7] As can be seen from Table 7, the spacer of Example 19 is the spacer 8
Although the thermal resistance was slightly larger than that of the eighteenth embodiment, when the metal heat conductor 5 made of the solder material was pressed, the solder material flowed in the horizontal direction or the adhesive applied in advance was used. The protrusion of the adhesive 3 from the layer 4 of the adhesive 3 was reduced, and the work surface was improved.

(Example 20) In Example 19, the wiring 11 was formed on the surface of the ceramic base 2 opposite to the layer 4 of the adhesive 3 and the mounting portion of the heat-generating component 9 was provided to form a ceramic wiring board 2a. As the adhesive 3, a silicone-based adhesive 3 containing a thermally conductive filler (Toshiba Silicone Co., Ltd., “T
SE3280-G ") and a metal heat conductor 5 (1.5 ×
1.5 × 0.1 mm) was provided on the layer 4 of the adhesive 3 so as to be evenly arranged at intervals of 2 mm to obtain a joined body A having the configuration of FIG. (Example 21) In Example 20, the wiring 11 is formed on the surface of the ceramic base 2 opposite to the layer 4 of the adhesive 3 and the mounting portion for the heat-generating component 9 is provided.
a, and a silicone adhesive 3 containing a thermally conductive filler (TSE3280-
G "), the metal heat conductors 5 are provided on the layer 4 of the adhesive 3 so as to be uniformly arranged at intervals of 2 mm in a portion other than the portion corresponding to the back surface of the mounting position of the heat generating component 9 and the vicinity thereof. In the portion corresponding to the back surface of the mounting position of the heat generating component 9 and in the vicinity thereof, the metal heat transfer member 5 is provided so as to have twice the occupation density of the metal heat transfer member 5 in other portions, and the structure of FIG. Was obtained. (Comparative Example 5) A joined body A was obtained in the same manner as in Example 20, except that the metal heat conductor 5 was not arranged in the layer 4 of the adhesive 3.

In the joined bodies A of Examples 20, 21 and Comparative Example 5, the same radiating fins were attached to the metal base 1 side of the joined body A, and the heat-generating components 9 were formed on the surface of the ceramic wiring board 2a. When the circuit was driven by mounting a small transformer, and the heat radiation characteristics of each joined body A were observed by a thermograph, the heat conduction speed of Examples 20 and 21 was higher than that of Comparative Example 5. It was confirmed that. Example 2 in which the metal heat transfer bodies 5 are arranged at high density on the back surface of the mounting portion of the heat generating component 9 and in the vicinity thereof
It was confirmed that the device of No. 1 could more efficiently release the generated heat as compared with the device of Example 15.

(Embodiment 22) In the configuration of Embodiment 21, a power IC is used as the heat-generating component 9, and the wire 9a connecting the heat-generating component 9 and the wiring 11 corresponds to the back surface at the position where the wiring 11 is connected. To the part and its vicinity,
Like the portion corresponding to the back surface of the mounting position of the heat-generating component 9 and the vicinity thereof, the metal heat transfer members 5 are provided so as to have twice the occupation density of the metal heat transfer members 5 in other portions, and are configured as shown in FIG. Was obtained.

In the joined body A of the twenty-second embodiment, the metal heat conductors 5 are arranged at a higher density than the other parts on the back surface of the connection position with the wire 9a on the wiring 11 and in the vicinity of the joint.
The high-density metal heat conductor 5 suppresses the absorption of the ultrasonic wave applied to the connection position between the wire 9a and the wire 9a on the wiring 11 at the time of wire bonding between the wire 1 and the wire 9a. As a result, as compared with Example 22, it was confirmed that the connection failure of the wire 9a was reduced and the work surface was improved.

(Embodiment 23) In addition to the structure of the embodiment 22, a part of the ceramic wiring board 2a on the wiring 11 has S
n-Ag based solder (manufactured by Nippon Superior Co., Ltd., “Sn9
6)), a plurality of metal heat conductors 5 having dimensions of 0.5 × 0.5 × 0.1 mm in height are formed at intervals of 0.5 mm, and reflowed at a temperature of 250 ° C. The copper lead frame 10 was placed on the wiring 11 where the metal heat conductor 5 was formed, and reflowed at a temperature of 250 ° C. Then, the adhesive 3 (TSE325, manufactured by Toshiba Silicone Co., Ltd.) is inserted into the gap between the lead frame 10 and the wiring 11.
0 ”) was injected with a syringe to form a joint structure in which the thickness of a joint layer between the lead frame 10 and the wiring 11 was 100 μm, and a joined body A having a configuration shown in FIG. 6 was obtained.

In the joined body of Example 22, the bonding between the metal substrate 1 on the back side and the ceramic wiring board 2a and the wiring 11 on the front side lead frame 10 and the ceramic wiring board 2a were performed.
Can be simultaneously performed using the metal heat conductors 5, respectively, so that a large current circuit requiring a conductor thickness can be efficiently formed.

The wiring 11 to which the lead frame 10 is not connected can be used as a control circuit.
It was also possible to obtain a wiring board in which a large current circuit and a control circuit coexist.

[0081]

As described above, according to the first aspect of the present invention, in a joined body in which a metal base and a ceramic base are bonded via an adhesive, at least one of the metal base and the ceramic base is applied with an external pressure. The heat transfer between the metal base and the ceramic base is performed by directly joining the deformable metal heat transfer body and disposing the metal heat transfer between the metal base and the ceramic base. Rate can be increased, and as a result, it is possible to obtain a joined body of a metal base material and a ceramic base material having better thermal conductivity than a conventional joined body joined only with an adhesive containing a thermally conductive filler. Things. Also, by pre-pressing the surface of the metal heat transfer body directly bonded to one base material facing the other base material, the shape of the metal heat transfer body can easily follow the shape of the other base material Can be
Even when using a substrate having warpage or undulation, a gap is created between the metal heat conductor and the substrate to prevent the thermal conductivity from partially deteriorating, A joined body with a ceramic base can be obtained.

Further, according to the second aspect of the present invention, by pressing the metal heat transfer member between the metal base material and the ceramic base material in a state where the metal heat transfer member is heated to a temperature higher than the melting point of the metal heat transfer member,
Since the metal heat transfer body is directly joined to at least one of the metal base and the ceramic base, the shape of the metal heat transfer can more easily follow the shape of the other base, and at the same time, the metal heat transfer It is also possible to join the body to both substrates.

According to a third aspect of the present invention, since a metal heat conductor having a melting point lower than the melting points of the metal base material and the ceramic base material is used, the metal heat transfer body is bonded to the base material in a state where the metal heat transfer member is bonded to the base material. When the heating element is heated and melted, there is no possibility that the base material is melted.

According to a fourth aspect of the present invention, since the metal heat conductor is discretely arranged between the metal base and the ceramic base,
The difference in the coefficient of thermal expansion between the two substrates is large, and even when stress is applied between the two substrates due to the difference in the coefficient of thermal expansion between the metal substrate and the ceramic substrate when the joined body is heated. In this way, stress can be absorbed by the elastic deformation of the adhesive interposed between the metal heat transfer bodies, and the concentration of stress at the joint interface between the metal heat transfer body and both base materials can be reduced, and the base material and metal transfer medium can be absorbed. It is possible to prevent dissociation of the joint with the heat body.

According to the fifth aspect of the present invention, since the metal heat transfer member is formed as a projection, the effect of relieving the concentration of stress on the bonding interface between the metal heat transfer member and both substrates is high, and the bonding member Even when the size is large and the effect of stress is high,
It is possible to prevent the bond between the base material and the metal heat conductor from being dissociated.

According to the invention of claim 6, since the metal heat conductor is a solder material, the metal heat conductor is interposed between the base materials, and then a slight load is applied to the base material from the outside to apply pressure. By heating, even in the case of using a substrate having warpage or undulation, it is possible to prevent a gap from being generated between the metal heat conductor and the substrate, thereby preventing the thermal conductivity from being partially degraded, and thereby making the thermal conductivity uneven. It is possible to obtain a joined body of a metal base and a ceramic base having a small size.

According to the seventh aspect of the present invention, since the surface facing the metal base is made of a metallized ceramic base,
When the metal heat transfer body is directly bonded to the ceramic substrate, it can be easily bonded.

Further, according to the present invention, since a spacer is interposed between the metal base and the ceramic base, even if the solder material is melted while applying a load when the bases are joined together, Distance will not be too narrow,
The solder material disposed in the area where the gap between the two base materials is narrow can prevent laterally flowing out of the area, and the pre-applied adhesive has a metal base and a ceramic base. It does not protrude from between.

According to a ninth aspect of the present invention, a ceramic wiring board is used as a ceramic base material, and the occupied density of the metal heat conductor disposed on the back surface of the mounting position of the heat-generating component on the ceramic wiring board and in the vicinity thereof is different. Is higher than the occupied density of the metal heat conductor in the portion, the thermal conductivity of the joined body is higher at the mounting position of the heat-generating component and in the vicinity thereof than at other portions, and the heat generated from the heat-generating component is efficiently discharged. It can dissipate heat.

Further, according to a tenth aspect of the present invention, a ceramic wiring board is used as a ceramic base material, and a metal heat conductor disposed on the back surface of a portion where wire bonding is performed on wiring of the ceramic wiring board and in the vicinity thereof is occupied. Since the density is higher than the occupation density of the metal heat conductor in other parts, the ultrasonic waves emitted from the wire bonder that performs the wire bonding by the ultrasonic wave are absorbed by the adhesive layer when performing the wire bonding between the wiring and the wire It is possible to prevent the occurrence of bonding failure due to the metal heat conductor arranged at a high occupation density on the back surface of the wire bonding position on the wiring and in the vicinity thereof, and the wire bond connection can be performed with high yield. is there.

[Brief description of the drawings]

FIGS. 1A to 1E are cross-sectional views each showing an example of an embodiment of the present invention.

FIG. 2 is a sectional view showing another example of the embodiment of the present invention.

FIG. 3 is a sectional view showing still another example of the embodiment of the present invention.

FIG. 4 is a sectional view showing still another example of the embodiment of the present invention.

FIG. 5 is a sectional view showing still another example of the embodiment of the present invention.

FIG. 6 is a sectional view showing still another example of the embodiment of the present invention.

[Explanation of symbols]

 A Joined Body 1 Metal Base 2 Ceramic Base 2a Ceramic Wiring Board 3 Adhesive 4 Adhesive Layer 5 Metal Heat Conductor 8 Spacer 9 Heating Part 11 Wiring

Claims (10)

[Claims] In a joined body in which a metal base and a ceramic base are bonded via an adhesive, at least one of the metal base and the ceramic base is directly provided with a metal heat conductor deformable by external pressure. And a metal substrate and a ceramic substrate, wherein the metal heat transfer member is disposed between the metal substrate and the ceramic substrate. 2. A method in which a metal heat transfer body is pressurized by sandwiching the metal heat transfer body between a metal base and a ceramic base in a state where the metal heat transfer body is heated to a temperature equal to or higher than the melting point of the metal heat transfer body. The joined body of a metal base and a ceramic base according to claim 1, wherein the joined body is directly bonded to at least one of the base and the ceramic base. 3. The metal base and the ceramic base according to claim 1 or 2, wherein the metal base has a melting point lower than the melting points of the metal base and the ceramic base. And conjugate. 4. The metal substrate and the ceramic substrate according to claim 1, wherein the metal heat conductor is discretely arranged between the metal substrate and the ceramic substrate. Joint with material. 5. The joined body of a metal substrate and a ceramic substrate according to claim 1, wherein the metal heat conductor is formed as a protrusion. 6. The joined body of a metal substrate and a ceramic substrate according to claim 1, wherein the metal heat conductor is a solder material. 7. The joined body of a metal substrate and a ceramic substrate according to claim 1, wherein a surface facing the metal substrate is made of a metallized ceramic substrate. 8. The joined body of a metal base and a ceramic base according to claim 1, wherein a spacer is interposed between the metal base and the ceramic base. 9. A ceramic wiring board is used as a ceramic base material, and the occupied density of the metal heat transfer body disposed on the back surface of the mounting position of the heat-generating component on the ceramic wiring board and in the vicinity thereof is different from that of the other parts. The joined body of a metal base and a ceramic base according to any one of claims 1 to 8, wherein the bonded base is higher than the occupation density of the body. 10. A ceramic wiring board is used as a ceramic base material, and the occupation density of a metal heat conductor disposed on the back surface of a portion where wire bonding is performed on wiring of the ceramic wiring substrate and in the vicinity thereof is different from that of another portion. The joined body of a metal substrate and a ceramic substrate according to any one of claims 1 to 9, wherein the occupation density of the metal substrate is higher than the occupation density of the metal heat conductor.