JPH053379A - Ceramic composite board for mounting electric parts - Google Patents

Abstract

PURPOSE:To provide a ceramic composite board where the property of ceramic can be made the most of and the thermal expansion coefficient can be made approximately the same as those of the electronic parts to be mounted. CONSTITUTION:Ceramic composite boards 12, which are made by charging resin into the open pores of porous oxide sintered substances which have Al2O3 and SiO2 for the their main ingredients, are united, respectively, on both sides of a fiber reinforcing board 11 impregnated with resin, and metallic foils 13 for conductor circuits are united on the surfaces of both these ceramic composite boards 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic composite substrate, and more particularly to a composite of a ceramic composite plate in which resin is filled in open pores of a porous oxide sintered body and a fiber reinforced plate impregnated with the resin. The present invention relates to a ceramic composite substrate.

[0002]

2. Description of the Related Art As a substrate for mounting electronic parts, a so-called resin substrate is generally adopted because it is easy to manufacture and can be provided at a low cost, but it is necessary to have sufficient heat resistance. In some cases, so-called ceramic substrates may be employed.

As shown in FIG. 5, a conventional ceramic substrate is formed by integrally forming one or both sides of a plate-shaped ceramic plate with a metal foil such as copper to be a conductor circuit. Such a ceramic substrate is formed of, for example, an alumina-based sintered body or a mullite-based sintered body, but it is easily cracked when it is handled, and its advantage is its high hardness. It is very difficult to machine such as through hole machining. Moreover, since the ceramic substrate having the ceramic plate as a base material must be formed in consideration of shrinkage due to its firing, it is not only very difficult to manufacture a ceramic substrate having a relatively large area, but also a dense substrate. Therefore, it is heavy.

In order to eliminate the above-mentioned essential disadvantages of the ceramic substrate, the applicant has disclosed in Japanese Patent Laid-Open No. 61-287190 that the ceramic plate itself is made of a porous oxide sintered body and the We have already proposed a ceramic composite substrate using a ceramic composite plate in which the open pores of a porous oxide sintered body are filled with resin. Then, as shown in FIG. 4, there is also a proposal to integrally form a resin-impregnated glass cloth layer on at least one surface of such a ceramic composite substrate to eliminate the fragility of the ceramic composite plate itself. I'm doing it.

By the way, according to a subsequent study by the present inventors, when a glass cloth layer impregnated with a resin is integrated on the outside of the ceramic composite substrate, the coefficient of thermal expansion of the entire ceramic composite substrate is increased. I realized that it was more influenced by the layers. Conversely, the coefficient of thermal expansion of the completed ceramic composite substrate may be relatively large compared to that of the electronic components to be mounted. This has become an important issue when attempting to increase the density of the wiring circuit.

[0006] Therefore, the present inventors have considered how to make the thermal resistance of this type of ceramic substrate sufficiently resistant to cracking and the coefficient of thermal expansion to be substantially the same as that of the electronic component while making full use of the heat resistance. As a result of various studies, the present invention has been completed.

[0007]

The present invention has been made based on the above-mentioned background, and the problem to be solved is to further improve the ceramic substrate.

The object of the present invention is to provide a ceramic composite substrate which can make full use of the characteristics of ceramics and can make its coefficient of thermal expansion substantially the same as that of an electronic component to be mounted. To provide.

[0009]

Means for Solving the Problems In order to solve the above-mentioned problems, the means adopted by the present invention will be described with reference to the reference numerals used in the examples. , A ceramic composite plate formed by filling resin into open pores of a porous oxide sintered body containing Al ₂ O ₃ and SiO ₂ as main components is integrated respectively, and a conductor is formed on the surface of both ceramic composite plates. It is a ceramic composite substrate for mounting electronic components, characterized by integrating a metal foil for circuits. "

That is, the ceramic composite substrate 10 according to the present invention needs to be constructed by integrating the resin composite impregnated fiber reinforced plate 11 and the ceramic composite plate 12 on both sides. The reason is that if there is a fiber-reinforced plate 11 impregnated with a resin on the outside, the coefficient of thermal expansion of the entire ceramic composite substrate 10 is defined by the fiber-reinforced plate 11 and the resin, and the coefficient of thermal expansion is higher than that of an electronic component. Is also large, and in that sense, the ceramic composite plate 1 that can be adjusted to the thermal expansion coefficient of the electronic component.
It is necessary to place 2 on the outside. Further, by forming the ceramic composite plate 12 having a small coefficient of thermal expansion on the outside, the formation and integration of the metal foil 13 integrated to form a conductor circuit on the front surface side of the fiber reinforced plate 11 are performed.
In order to be more certain than for the above, it is necessary to configure as described above.

The ceramic composite plate 12 constituting the ceramic composite substrate 10 of the present invention is a composite body in which resin is filled in open pores of a porous body containing Al ₂ O ₃ and SiO ₂ as main components. is necessary. The reason for this is that, for example, a mullite sintered body or the like which has been conventionally used as a substrate for electronic circuits is a dense sintered body and thus has high hardness and extremely poor machinability. The body has remarkably good machinability after sintering, and since the open pores are filled with resin, the ceramic composite substrate 10
This is because it also has gas impermeability, which is indispensable.

As the resin to be filled in the open pores of the porous body containing Al ₂ O ₃ and SiO ₂ as the main components, epoxy resin, polyimide resin, trimazine resin, polyparabanic acid resin, polyamideimide resin, silicon resin,
A resin selected from an epoxy silicone resin, an acrylic acid resin, a methacrylic acid resin, an aniline acid resin, a phenol resin, a urethane resin, a furan resin, and a fluororesin can be used alone or in combination.

The ceramic composite plate 12 constituting the ceramic composite substrate 10 of the present invention has an open porosity of 10 to 7.
It is preferably in the range of 0% by volume. The reason is,
This is because if the open porosity is less than 10% by volume, the machinability is significantly deteriorated, while if it is more than 70% by volume, the substantial strength is almost lost and the material is easily broken during handling.

In the ceramic plate for the ceramic composite plate 12 constituting the ceramic composite substrate 10 of the present invention, each component is a component within the range of 15 to 50% Al ₂ O _{3 and} 45 to 80% SiO _2. It is desirable to be composed by the ratio. The reason for this is that if it is out of this range, it is difficult to bring the coefficient of thermal expansion of the porous body close to the coefficient of thermal expansion of the silicon integrated circuit, and the ceramic composite substrate 10 on which the silicon integrated circuit can be directly mounted is manufactured. Because it is difficult.

The crystal structure of the ceramic plate employed in the present invention is preferably cordierite which mainly contains MgO as a component other than Al ₂ O ₃ and SiO _{2 in} the range of 5 to 35% by weight. The reason is that the thermal expansion coefficient of cordierite is close to that of silicon integrated circuits.
This is because it is possible to manufacture the ceramic composite substrate 10 on which the silicon integrated circuit which is the object of the present invention can be directly mounted. In this case, it is more advantageous that the content rate of the cordierite structure is 50% or more.

Also, the ceramic composite plate 1 for the present invention
No. 2 preferably has a porosity of 10% by volume or less. The reason is that if the porosity is larger than 10% by volume, it is difficult to impart gas impermeability to the ceramic composite substrate 10, and it is particularly preferable that the porosity is 5% by volume or less.

Further, the ceramic composite substrate 10 of the present invention.
Is advantageous in that its coefficient of thermal expansion is as close as possible to that of the silicon integrated circuit, preferably in the range of 2 to 6 × 10 ⁻⁶ / ° C., and particularly 3 to 5.5 × 10 ^{−. 6} /
It is advantageously in the range of ° C.

The ceramic composite substrate 10 of the present invention has a large thermal conductivity as a whole as compared with the glass-epoxy composite, and its thermal expansion coefficient is close to that of a silicon integrated circuit. It is extremely suitable as a chip-on-board type substrate that requires characteristics and is significantly affected by the coefficient of thermal expansion.

As the fiber reinforcing plate 11 positioned between the ceramic composite plates 12 as described above, a cloth may be used to homogenize the coefficient of thermal expansion of the entire ceramic composite substrate 10 and to continuously form it in the manufacturing method described later. However, it is also possible to apply the mixture of the fiber and the resin to the inner surface of the ceramic composite plate 12, for example. It is advantageous to use glass fiber, asbestos fiber, carbon fiber, ceramic fiber or the like as the inorganic fiber material for forming such a fiber reinforcing plate 11, and to impregnate such inorganic fiber. As the resin, the same resin as that used for filling the open pores of the ceramic porous body described above can be used.

Next, a method for manufacturing the ceramic composite substrate 10 of the present invention will be described. As a starting material for the ceramic composite plate 12 for forming the ceramic composite substrate 10 according to the present invention, an oxide powder mainly having a cordierite crystal structure is suitable. The starting material having the crystal structure of cordierite is molded into a green body, and the green body is fired in a non-reducing atmosphere in a temperature range where the amount of liquid phase produced is 5% by weight or less. And then filling the open pores of the porous body with a resin.

As a method of filling the open pores of the porous body with this resin, a method of heating and melting the resin to impregnate it, a method of dissolving the resin in a solvent to impregnate it, and a resin in a monomer state A method of converting it into a polymer after impregnation, or a method of dispersing a finely divided resin in a dispersion medium liquid, impregnating this dispersion liquid, drying and then baking the resin at the melting temperature of the resin can be applied.

In order to manufacture the ceramic composite substrate 10 of the present invention, the open pores of the porous body may be preliminarily subjected to silane coupling treatment and then impregnated with resin.

The ceramic composite plate 1 formed as described above
2 is integrated on both sides of the resin-impregnated fiber-reinforced plate 11, which, as shown in FIGS. 2 and 3,
It is advantageous to carry out continuously. That is, the fiber-reinforced plate 11 wound around a reel or the like is successively and continuously immersed in the resin tank, and both sides of the fiber-reinforced plate 11 pulled out from the resin tank are covered with the ceramic composite plate configured as described above. The 12 are sequentially and continuously integrated by means such as a thermocompression press. In this case, the ceramic composite plate 12 in which the metal foil 13 is preliminarily integrated on the front surface side may be used, but the ceramic composite plate 12 integrated on both surfaces of the fiber reinforced plate 11 is long on the front surface side. The metal foil 13 may be integrated and implemented by continuously pasting it. After that, the fiber-reinforced plate 11 and the like are cut in accordance with the shape of each ceramic composite plate 12 to form the solid ceramic composite substrate 10 having the metal foil 13 on the outermost surface.

Further, the ceramic composite substrate 1 according to the present invention
When it is desired to form a through hole or the like on 0, it is sufficient to use a commercially available carbide drill.
Further, the metal foil 13 of the ceramic composite substrate 10 is etched by a conventional method to form a conductor circuit necessary for mounting an electronic component.

[0025]

In the ceramic composite substrate 10 configured as described above, the physical properties of the whole are as shown in Table 1 below when compared with other examples.

[0026]

Here, in Comparative Example 1, the resin is impregnated into the pores of the porous ceramic as shown in FIG. 5, and the copper foil is directly integrated on the surface. Comparative Example 2 is shown in FIG. As shown in the figure, a resin-impregnated fiber-reinforced layer is formed on both sides of a porous ceramic in which pores are impregnated with a resin, and a copper foil is integrated on the back surface thereof. Comparative resin substrate Comparative Example 4 is a general alumina sintered body, and each thermal conductivity is at 25 ° C.

As shown in Table 1, the coefficient of thermal expansion of the ceramic composite substrate 10 according to the present invention is 3.5 × 10 ^-6 / ° C.
And the thermal expansion coefficient of the electronic components to be mounted 3.8 × 10 ^-6 / ° C
In addition, compared to other comparative examples, the value is more approximate,
Even if the electronic components mounted on the ceramic composite substrate 10 generate heat and expand, the electrical connection portion to the ceramic composite substrate 10 does not peel off.

Further, the ceramic composite substrate 1 according to the present invention
The flexural strength and fracture toughness of 0 are slightly inferior to those of Comparative Example 2, for example, but this is not a problem in practice. In particular, the fracture toughness is a physical property related to the case of handling this kind of electronic component mounting substrate, but the fracture toughness at the time of handling is actually the extent that the ceramic composite substrate 10 of the present invention has. This is because there is no problem in the above, and even if the value is raised further, it will not be effective. What is more important than that is that even if the fracture toughness is lowered to a handleable range, the coefficient of thermal expansion thereof should be matched to that of the electronic component to be mounted as much as possible. Has been realized.

[0030]

EXAMPLE Next, a ceramic composite substrate 10 according to the present invention
Will be described in detail according to one embodiment of the manufacturing method.
First, in order to mold the porous oxide sintered body of the ceramic composite plate 12 constituting the ceramic composite substrate 10 according to the present invention, the average particle size is 2.0 μm and the impurity content is shown in Table 2. At this time, 100 parts by weight of cordierite powder, 2 parts by weight of polyvinyl alcohol, 1 part by weight of polyethylene glycol, 0.5 part by weight of stearic acid and 1 part of water.
00 parts by weight were blended, mixed in a ball mill for 3 hours, and then spray dried.

[0031]

An appropriate amount of this dried product was sampled and molded at a pressure of 1.0 t / cm ² using a metal pressing die to obtain a size of 10
0mm × 100mm × 2mm, density 1.5g / cm ²
(60% by volume) of the green form was obtained.

This green body was placed in an alumina crucible and calcined in air at atmospheric pressure at a temperature of 1400 ° C. for 1 hour.

The crystal structure of the obtained sintered body was cordierite, and as shown in Table 3, for example, the porous oxide sintered body of Example 1 had a density of 1.8 g / cm ² and an open porosity. Was 30% by volume. The average bending strength of this sintered body was 9.0 kg / mm ² , and the Knoop hardness was 140-
It was 180 kg / mm ² .

[0035]

Then, a two-component type epoxy resin was immersed in this sintered body under vacuum to impregnate it, and then, at about 150 ° C.
The ceramic composite plate 12 was obtained by curing at a temperature of. The proportion of epoxy resin in the voids of the sintered body was approximately 98.5% by volume.

0 to 300 ° C. of this ceramic composite plate 12
As shown in Table 4, for example, the coefficient of thermal expansion in Example 1 is 4 × 10 ⁻⁶ / ° C. and the volume resistivity (J
ISC 6481) is 10 ¹⁴ [Omega] cm or more, the surface resistivity (JIS C 6481) is 10 ¹² [Omega] cm or more and a dielectric constant had a very favorable properties as a ceramic composite substrate 5.0 and mounting electronic components.

[0038]

[Table 4]

The actual size of the porous oxide sintered body of the ceramic composite plate 12 having the above-described structure is
Length, width and thickness are 255 mm x 340 mm x 0.45 m
It was m.

Then, a metal foil 13 made of copper and having a thickness of 18 μm is integrated on the front surface side of the ceramic composite plate 12, and as shown in FIG. An adhesive tape 14 for attaching was attached. The integration of the metal foil 13 on the surface side of each ceramic composite plate 12 may be performed continuously after the integration of each ceramic composite plate 12 with the fiber reinforced plate 11. ..

In the case of this embodiment, the fiber reinforcing plate 11 is woven from glass fibers having a diameter of about 7 μm and a very long fiber length, for example, 103 g / m ² . Then, the fiber reinforced plate 11 was continuously passed through a tank of epoxy resin to obtain a resin reinforced fiber reinforced plate 11. With respect to the fiber reinforced plate 11, each of the above-mentioned ceramic composite plates 12 is bonded to the fiber composite plate 12 by using the adhesive tape 14 to form a large number of ceramic composite plates 1
2 was integrated on both front and back sides. Then, the individual ceramic composite substrate 1 as shown in FIG.
Each was cut out as 0.

The metal foil 13 of the ceramic composite substrate 10 formed as described above is subjected to predetermined etching to form a conductor circuit necessary for mounting electronic components.

[0043]

As described above in detail, in the present invention,
As illustrated in the above examples, "the resin is filled in the open pores of the porous oxide sintered body containing Al ₂ O ₃ and SiO ₂ as the main components on both sides of the fiber-reinforced plate impregnated with the resin. By integrating the ceramic composite plates formed by the above, and by integrating the metal foil for the conductor circuit on the surface of both ceramic composite plates, it is possible to make full use of the characteristics of the ceramic. In particular, it is possible to provide a ceramic composite substrate whose thermal expansion coefficient can be made substantially the same as that of the electronic component to be mounted.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a ceramic composite substrate according to the present invention.

FIG. 2 is a partial cross-sectional view when the respective ceramic composite substrates are formed as a continuous product via a continuous fiber-reinforced plate.

FIG. 3 is a cross-sectional plan view taken along line 1-1 of FIG.

FIG. 4 is an enlarged sectional view showing a conventional ceramic composite substrate.

FIG. 5 is an enlarged plan view showing another conventional ceramic composite substrate.

[Explanation of symbols]

 10 Ceramic Composite Substrate 11 Fiber Reinforcement Plate 12 Ceramic Composite Plate 13 Metal Foil

Claims (1)

[Claims] 1. A resin-impregnated fiber-reinforced plate on both sides,
Al₂O₃And SiO ₂Porous oxide-based firing
Ceramic formed by filling resin into open pores of a unit
Composite plates are integrated respectively, and both ceramic composite plates are integrated.
The metal foil for the conductor circuit is integrated on the surface of the
Ceramic composite substrate for mounting electronic components.