JP2002151811A - Substrate for wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate for wiring board upon which a metal is laminated and which has superior thermal conductivity and a high adhesive property with respect to the metal and is in a preceding stage of forming a printed wiring board, particularly, a wiring pattern that can quickly radiate generated heat. SOLUTION: This substrate 1 for wiring board is constituted of a carbonaceous substrate 2, coating polyimide films 3 formed on both surfaces of the substrate 2, and plated metal layers 4 formed on the films 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wiring board substrate.

[0002]

2. Description of the Related Art Conventionally, a printed wiring board used in various electric and electronic equipment fields is formed by wiring a so-called metal-attached laminate in which a metal foil such as a copper foil is laminated on a substrate by using a photoresist. It is manufactured by a photolithography technique of drawing a pattern and performing etching or the like in accordance with the wiring pattern. In another case, a so-called lead frame formed by punching a wiring pattern from a metal plate such as a copper plate is laminated on a substrate. Conventionally, as a substrate on which the metal foil and the lead frame are laminated, a substrate made of a synthetic resin such as a phenol resin has been frequently used.

In general, a printed wiring board may generate heat, depending on the type of elements mounted thereon, and there is a possibility that an unexpected trouble may occur if heat is accumulated and the temperature of the circuit rises. It is required to dissipate heat quickly. However, when using a conventional synthetic resin substrate,
Because of its poor thermal conductivity, there is a problem that it is difficult to dissipate the accumulated heat.

When dissipating the accumulated heat, not only the thermal conductivity of the substrate on which the metal is laminated, but also the adhesion between the metal and the substrate is greatly affected. Therefore, it has been conventionally desired to improve the overall heat dissipation by firmly adhering the metal to the substrate.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional circumstances, the present invention provides a substrate on which a metal is laminated has excellent thermal conductivity and high adhesion between the metal and the substrate. It is an object of the present invention to provide a printed wiring board which can be dissipated into a wiring board, particularly a wiring board substrate which is a stage before forming a wiring pattern.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that a carbonaceous substrate made of a carbonaceous material having excellent thermal conductivity is used as a substrate for laminating a metal. It has been found that the above object can be achieved by selecting a plating method as a means for forming a metal layer, and completed the present invention.

That is, the wiring board substrate of the present invention comprises a carbonaceous substrate, a polyimide coating film provided on the carbonaceous substrate,
It is characterized by comprising a polyimide film or a polyimide vapor-deposited polymer layer, and a metal layer by plating provided on the polyimide coating film, the polyimide film or the polyimide vapor-deposited polymer layer.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments. First, an embodiment (1) of the present invention is shown in FIG. The wiring board substrate 1 shown in FIG. 1 has a schematic structure in which a polyimide film 3 is provided on a carbonaceous substrate 2 and a metal layer 4 is formed on the polyimide film 3 by plating. Polyimide coating 3 and metal layer 4 by plating
May be provided on both sides of the carbonaceous substrate 2 as shown in FIG. 1 or may be provided only on one side of the carbonaceous substrate 2.

As the carbonaceous substrate 2, a plate made of a carbonaceous material such as a carbon fiber reinforced carbon composite material using carbon fiber as a reinforcing material and carbon as a matrix, or an isotropic high-density carbon material is generally used. Used. When the thickness of the carbonaceous substrate 2 is too small, the strength of the substrate is reduced. On the contrary, when the thickness is too large, the weight increases and the cost increases. Therefore, the thickness is appropriately set in consideration of these factors. ５5 mm is appropriate.

As the carbon fiber reinforced carbon composite material used for the carbonaceous substrate 2, various conventionally known carbon fiber reinforced carbon composite materials can be appropriately selected and used.
In general, carbon fiber reinforced carbon composite materials have various arrangements of carbon fibers. The carbon fibers are aligned in one direction and arranged in a primary orientation to form a bundle.
There are secondary orientations made of woven cloth such as satin weave, tertiary orientations of carbon fibers so-called three-dimensionally woven, and felts and short fibers made of carbon fibers. In the present invention, various arrangements of carbon fibers can be appropriately selected and used. Further, the carbon fiber reinforced carbon composite material is generally prepared by impregnating a carbon fiber aggregate having various orientations described above with a thermosetting synthetic resin such as a phenol resin or a matrix material such as petroleum pitch to prepare a prepreg. The prepreg is manufactured by laminating a plurality of the prepregs as necessary, heating the matrix under pressure to harden the matrix material, and firing the matrix material in an inert atmosphere at a high temperature to carbonize the matrix material. If the carbon fiber is short fiber,
In general, short fibers of carbon fiber are mixed with the matrix material,
The mixture is formed into a predetermined shape, and the formed material is heated under pressure to harden the matrix material, and then fired at a high temperature in an inert atmosphere to carbonize the matrix material to produce a carbon fiber reinforced carbon composite material. Is done. The carbon fiber-reinforced carbon composite material used for the carbonaceous substrate 2 may be a plate-like material having a predetermined thickness in advance, or a carbon fiber-reinforced carbon composite material manufactured in a block shape and having a predetermined thickness. It may be cut into a plate shape and cut out. Further, the carbon fibers and the carbon matrix constituting the various carbon fiber reinforced carbon composite materials may be graphitized.

Among the various carbon fiber reinforced carbon composite materials described above, a block of a primary orientation carbon fiber reinforced carbon composite material in which carbon fibers are aligned in one direction in a carbon matrix is used to remove the carbon fiber in the direction in which the carbon fibers are arranged. The plate-like object cut out by cutting into a plate having a predetermined thickness in a direction perpendicular to
Particularly, it is preferably used as the carbonaceous substrate 2 because of its excellent thermal conductivity in the thickness direction. A cross section of such a carbonaceous substrate 2 is schematically shown in FIG. Carbonaceous substrate 2 of FIG.
Has carbon fibers 22 arranged in a thickness direction in a carbon matrix 21. The cutting of the plate-like material from the block of the carbon fiber reinforced carbon composite material can be performed by a cutting means known per se such as a wire saw or a rotating diamond saw.

Also, when an isotropic high-density carbon material is used as the carbonaceous substrate 2, various conventionally known isotropic high-density carbon materials can be appropriately selected and used. The isotropic high-density carbon material is generally obtained by firing fine particles of sinterable graphite precursor such as raw coke or mesocarbon microbeads at a high temperature while pressing, or by using graphite fine particles or carbon whisker powder. It is manufactured by mixing a body or the like with a binder composed of a carbon precursor such as a pitch or a synthetic resin, press-molding and firing. The isotropic high-density carbon material used for the carbonaceous substrate 2 may be manufactured in a plate shape having a predetermined thickness in advance, or may be a predetermined isotropic high-density carbon material manufactured in a block shape. It may be cut into a plate having a thickness. Also,
The above-mentioned various isotropic high-density carbon materials may be graphitized.

The above-mentioned carbon fiber reinforced carbon composite material or isotropic high-density carbon material is generally porous having fine pores derived from the production process. Then, the thermal conductivity is further improved by impregnating the fine pores of these materials with an inorganic coating agent or a metal to make them nonporous. Therefore, in the present invention, each of the carbonaceous materials described above can be used as the carbonaceous substrate 2 by impregnating the fine pores thereof with an inorganic coating agent or a metal, if necessary, to further improve the thermal conductivity of the substrate. From the viewpoint of this, it is preferable to do so.

The inorganic coating agent to be impregnated into each of the carbonaceous materials is an inorganic material which is liquid and can be impregnated into fine pores of the carbonaceous material, and is cured after impregnation to make the carbonaceous material nonporous. Various inorganic coating agents that form a cured product can be appropriately selected and used. Examples thereof include an inorganic silicon-containing polymer in which a crosslinking reaction proceeds at room temperature or under heating to form a ceramic-like cured product,
Inorganic binders containing cement such as alumina cement, water glass, and the like are included. These inorganic coating agents can be diluted with an organic solvent to enhance their impregnation. Still more specific examples of the inorganic coating agent include HEATLES GLASS GA series (trade name: Homer Technology Co., Ltd.) which forms a silicon-containing polymer, and Tonen polysilazane, a polysilazane (trade name, manufactured by Tonensha Co., Ltd.). ),
Redproof MR-100 series (trade name: manufactured by Atsushi), which is an inorganic binder, and the like.

As a method for impregnating the fine pores of the carbonaceous material with the inorganic coating agent, a method of applying the inorganic coating agent to the carbonaceous material by a brush or the like, a method of dipping the carbonaceous material in the inorganic coating agent, a method of applying high pressure And a method of injecting the inorganic coating agent into the carbonaceous material under a high vacuum. The inorganic coating agent impregnated in the carbonaceous material is cured. At this time, the curing conditions of the inorganic coating agent are as follows:
It can be appropriately set according to the type of the inorganic coating agent used.
In the case of LESS GLASS, generally about 130 ° C.
And heating for 60 minutes.

In the case of impregnating each of the above carbonaceous materials with a metal, generally, aluminum, copper or both are preferably used. As a method of impregnating a metal into the fine pores of the carbonaceous material, a method of impregnating a metal such as molten aluminum or copper under high temperature and high pressure can be used. Examples of the carbonaceous material impregnated with aluminum include CC-MA (trade name: C / C composite base manufactured by Advanced Materials Co., Ltd. in which carbon fibers are primarily arranged) and C-MA
MA (trade name: isotropic high-density carbon material base manufactured by Advanced Materials Co., Ltd.) and the like. As the carbonaceous material impregnated with copper, MB-18 (trade name: carbon fibers are primarily arranged) C / C composite base manufactured by Mobius A.T.

Next, the polyimide coating film 3 can be formed by applying various conventionally known polyimide coating materials to the carbonaceous substrate 2 or the like. In addition, polyimide paint,
Either a type in which polyimide acid is dissolved in a solvent or a type in which polyimide resin is dissolved in a solvent can be applied, but the latter method does not require a dehydration imidization step by heating and has an insulating property at a relatively low temperature. It is preferably used because a coating film excellent in the quality can be obtained. Specific examples of such a polyimide paint include Rica Coat (trade name: manufactured by Shin Nippon Rika Co., Ltd.),
Upilex S (trade name: manufactured by Ube Industries) and the like. In addition, various additives can be added to the polyimide paint in order to improve insulation properties and stability of the coating film.

If the thickness of the polyimide coating film 3 is too large, the thermal conductivity in the thickness direction of the wiring board substrate 10 may be impaired. Since the insulating property is not ensured, it is appropriately set in consideration of these balances. Generally, it is preferable that the thickness be about 5 to 150 μm.

A preferred form of the polyimide coating 3 is a polyimide electrodeposition coating. The polyimide electrodeposition coating film can be formed from various kinds of polyimide electrodeposition coating materials in which a conventionally known resin component is polyimide and a medium is a cation solution. Various additives can be added to the polyimide electrodeposition paint in order to improve the insulating property and the stability of the coating film. And the polyimide electrodeposition coating film can be obtained by electrodepositing the above-mentioned polyimide electrodeposition paint on the carbonaceous substrate 2. The electrodeposition method can be performed by appropriately selecting and employing a conventionally known method.

Subsequently, a metal layer 4 is formed on the polyimide coating film 3 by plating. As the plating method,
Various conventionally known plating methods can be appropriately adopted as a method of plating a plastic such as polyimide. Specifically, wet methods such as electroless plating, vacuum deposition,
Dry methods such as low-temperature sputtering and ion plating can be used. Among them, a method using electroless plating and vacuum deposition is preferably used in that the metal layer 4 can be efficiently formed. The thickness of the metal layer 4 formed by plating is preferably at least 15 μm or more in order to function as a circuit.

When the metal layer 4 is formed by electroless plating, the plate-like material having the polyimide coating film 3 formed on the carbonaceous substrate 2 is immersed in a plating solution containing metal ions, a reducing agent and the like. It is performed by At this time, since the polyimide coating film 3 is weak to strong alkali, the pH of the plating solution is 1
It is preferable to adjust to 2.0 to 12.5. In performing the electroless plating, a chemical etching process can be performed in advance to roughen the surface of the polyimide coating film 3 and to impart hydrophilicity to the coating film surface. In addition, in order to efficiently perform initial metal deposition by electroless plating, palladium,
A catalyst layer of silver, gold, platinum or the like may be formed. Further, the metal layer 4 is formed thicker and the metal layer 4 is formed.
For the purpose of increasing the mechanical strength of the metal layer, electrolytic plating can be further performed on the metal layer formed by electroless plating.

In the case where the metal layer 4 is formed by vacuum deposition, a plate-like material having the polyimide coating 3 formed on the carbonaceous substrate 2 is coated with copper, by a conventionally known vacuum deposition method.
This is performed by uniformly depositing a metal such as nickel.

Next, an embodiment (2) of the present invention is shown in FIG. The wiring board substrate 1 shown in FIG.
This is an example in which a polyimide film 5 is used instead of the polyimide coating film 3 in FIG. That is, the polyimide film 5 is laminated on the carbonaceous substrate 2, and the metal layer 4 is formed on the polyimide film 5 by plating.
A specific example of such a polyimide film 5 is a film-type polyimide adhesive such as Iupitite (trade name, manufactured by Ube Industries, Ltd.). Then, when manufacturing the wiring board substrate 11 using the polyimide film 5, the polyimide film 5 is laminated on the carbonaceous substrate 2, and the two are bonded by hot pressing, and then the metal layer 4 is formed by plating. Can be manufactured.

Further, Embodiment (3) of the present invention is shown in FIG.
Shown in In the wiring board substrate 1 of FIG. 3, a polyimide coating film 3 similar to that of the above embodiment (1) is provided on a carbonaceous substrate 2,
After the same polyimide film 5 as in the above embodiment (2) is laminated on the polyimide coating film 3 and bonded by heating and pressing, a metal layer 4 is formed on the polyimide film 5 by plating. You. In the example of FIG. 3, when the polyimide film 5 is laminated and heated and pressed, the coating material for forming the polyimide coating film 3 flows so as to fill the pores of the holes on the surface of the carbonaceous substrate 2, and adheres tightly to the carbonaceous substrate 2. The thermal conductivity is increased, and the carbonaceous substrate 2 and the metal layer 4 formed by plating are reliably separated by the polyimide film 5, so that the insulating property is ensured.

The polyimide coating film 3 and the polyimide film 5 in the above embodiments (1) to (3) can be added with an appropriate amount of a fine particle filler having a spacer function. Examples of the filler having the spacer function include silica, spherical alumina, and hollow balloon.

The polyimide coating film 3 and the polyimide film 5 in the above embodiments (1) to (3) can be embedded with an insulating woven or nonwoven fabric.
Here, "embed" means that the woven or nonwoven fabric is a polyimide coating 3
Alternatively, it means both a state in which it is wrapped in the polyimide film 5 and a state in which the woven or nonwoven fabric is partially located in the polyimide coating film 3 or the polyimide film 5 and located at the layer interface. . Such an example is shown in FIGS. The wiring board substrate 1 according to the embodiment (4) in FIG. 4 has the nonwoven fabric 6 embedded therein so as to be wrapped in the polyimide coating film 3, while FIG.
The wiring board substrate 1 according to the fifth embodiment (5)
Is located at the interface between the polyimide coating film 3 and the carbonaceous substrate 2 and partially penetrated into the polyimide coating film 3. By embedding the woven or nonwoven fabric in this way, the woven or nonwoven fabric functions as a spacer, and the carbonaceous substrate and the metal layer formed by plating are surely separated by at least the thickness of the woven or nonwoven fabric. Thus, the dielectric breakdown strength of the wiring board substrate can be improved.

The above-mentioned woven or non-woven fabric has an insulating property.
As long as it has heat resistance, it can be appropriately selected and used from various synthetic fibers, natural fibers, woven fabrics such as glass fibers, and nonwoven fabrics. Specifically, a nonwoven fabric made of aramid fiber such as meta-aramid paper (trade name: manufactured by DuPont Teijin Advanced Paper Co., Ltd.) can be mentioned as a suitable example. Also, if the thickness of the woven or non-woven fabric is too thick, the thermal conductivity of the entire wiring board substrate decreases,
On the other hand, if the thickness is too small, the effect of improving the dielectric breakdown strength cannot be obtained, so that it is appropriately set in consideration of these. Specifically, about 30 to 150 μm is appropriate, but the present invention is not limited to this.

In preparing a wiring board substrate using the woven or nonwoven fabric, for example, a polyimide coating film is formed on a carbonaceous substrate, and a woven or nonwoven fabric is laminated on the polyimide coating film. It can be manufactured by applying and curing a polyimide coating material thereon, and finally forming a metal layer by plating. Alternatively, apply and coat on a carbonaceous substrate.
After laminating a woven fabric or nonwoven fabric impregnated with polyimide paint by immersion etc., curing it and forming a polyimide coating film embedded with woven fabric / nonwoven fabric, it is made by forming a metal layer by plating Is also good. In the case of embedding a woven or nonwoven fabric in a polyimide film, for example, a woven fabric or a nonwoven fabric sandwiched between two film-type polyimide adhesives is laminated on a carbonaceous substrate, and the polyimide is heated by a press or the like. After melting and curing the adhesive, a metal layer is formed by plating, so that a target wiring board substrate can be manufactured. At this time, it is a matter of course that the woven or non-woven fabric requires heat resistance higher than the melting temperature of the film-type polyimide adhesive. In addition, when produced by each of the above methods, the woven fabric / nonwoven fabric is in a state of being inherently wrapped in a polyimide coating film or polyimide film. On the other hand, when the woven fabric / nonwoven fabric is positioned at the layer interface while being partially immersed in the polyimide coating film or the polyimide film, for example, a thin adhesive is applied to the carbonaceous substrate and then the woven fabric / nonwoven fabric is applied. A nonwoven fabric may be laminated, and a polyimide coating may be applied and cured to form a polyimide coating film, or a polyimide film may be laminated, and then a metal layer formed by plating on the nonwoven fabric. As the adhesive applied to the carbonaceous substrate, any material can be used as long as it can sufficiently bond the woven or nonwoven fabric to the carbonaceous substrate. As another example, when laminating a woven or nonwoven fabric with a carbonaceous substrate, the woven or nonwoven fabric can be laminated by welding without using the above adhesive.

Next, an embodiment (6) of the present invention is shown in FIG. The wiring board substrate 1 shown in FIG.
In this example, a polyimide vapor-deposited polymer layer 7 is used in place of the polyimide coating film 3 in FIG. That is, a polyimide layer is formed on the carbonaceous substrate 2 by vapor deposition polymerization, and the metal layer 4 is formed on the polyimide vapor deposition polymerization layer 7 by plating. Here, the polyimide vapor deposition polymerization layer can be formed by appropriately selecting and employing various vapor deposition polymerization methods.
That is, acid anhydrides such as pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride, and aromatic diamines such as oxydianiline, paraphenylenediamine, and benzophenone diamine are converted into carbon. Can be formed by co-evaporation on a quality substrate and imidization by heating or the like. The polyimide vapor-deposited polymer layer is easily controllable in film thickness and excellent in uniformity of the film, so that the carbonaceous substrate and the metal layer 4 formed by plating can be sufficiently firmly adhered to each other while being reliably insulated.

The wiring board substrate manufactured according to the above-described embodiments (1) to (6) is a printed wiring board on which printed wiring is suitably formed in accordance with a conventionally known photolithography technique. The obtained printed wiring board can be suitably used as a wiring board for various electric and electronic devices. In the above embodiment, the polyimide coating film 3, the polyimide film 5,
Alternatively, a printed wiring board can be obtained directly by forming the metal layer 4 by plating on the polyimide vapor-deposited polymerized layer 7 through a mask in a circuit pattern.

[0031]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to the following examples.

(Example 1) A 3 mm-thick plate-like carbon fiber reinforced carbon composite material (hereinafter referred to as "C / C composite") having carbon fibers arranged in a carbon matrix in the thickness direction. (Trade name: manufactured by Advanced Materials Co., Ltd.) was used as the carbonaceous substrate. One side of this carbonaceous substrate is brush-coated with Iupirex S (polyimide varnish, trade name: manufactured by Ube Industries, Ltd.), followed by a 20 μm-thick Iupitite (model number UPA-N1) as a film-type polyimide adhesive.
11, trade name: Ube Industries, Ltd.) and pressurized at 170 ° C. for 30 minutes at a pressure of 2.94 MPa. Next, copper was plated by electroless plating to obtain a target wiring board substrate. The total thickness of the polyimide layer in the obtained wiring board substrate was 50 μm, and the thickness of the copper plating was 40 μm. Next, the obtained substrate for a wiring board from which the copper plating on the surface was removed by etching was placed on an aluminum plate (thickness: 25 mm), and a thermal conductivity meter QTM-500 (manufactured by Kyoto Electronics Co., Ltd.) was used. The thermal conductivity was measured. The reason why the aluminum plate is used here is that a certain thickness is required for measuring the thermal conductivity. As a result of the measurement, a high value of 19.03 (W / m · K) was obtained.

Example 2 Instead of applying the polyimide varnish in Example 1 and laminating the film-type polyimide adhesive under pressure, a polyimide electrodeposition paint was applied at 30 V for 2.5 hours.
Minutes, electrodeposited at room temperature, dried at 80 ° C. for 10 minutes, and baked at 250 ° C. for 30 minutes to obtain a thickness of 20 μm.
A substrate for a wiring board was obtained in the same manner as in Example 1, except that the polyimide electrodeposition coating film was formed. As a result of measuring the thermal conductivity of the obtained wiring board substrate in the same manner as in Example 1, a high value of 20.18 (W / m · K) was obtained.

Example 3 A plate-like C / C composite having a thickness of 3 mm similar to that used in Example 1 was prepared by heatless glass GA-4 (N) (trade name: Room temperature curable silica manufactured by Homer Technology Co., Ltd.). Solution) under a reduced pressure of 9.31 kPa, impregnating the micropores of the plate-shaped C / C composite with heatless glass, and then leaving it to stand at room temperature for 50 minutes, and then heating it to 120 ° C. for 60 minutes. The heatless glass was cured to obtain a plate-like C / C composite impregnated with the heatless glass. A wiring board substrate was produced in the same manner as in Example 1 except that the plate-like C / C composite impregnated with the heatless glass was used as a carbonaceous substrate. The thermal conductivity of the obtained wiring board substrate was measured in the same manner as in Example 1, and as a result, 22.
A high value of 48 (W / m · K) was obtained.

(Example 4) MB-18 having a thickness of 3 mm (trade name: C / C composite base manufactured by Mobius A.T with primary arrangement of carbon fibers) impregnated with copper under high temperature and high pressure was used. Used as a carbonaceous substrate. On one side of this carbonaceous substrate, Iupirex S (polyimide varnish, trade name: manufactured by Ube Industries, Ltd.) is brush-applied, and then a 20 μm-thick Iupitite (model number UP) is used as a film-type polyimide adhesive.
A-N111, trade name: Ube Industries, Ltd.)
Pressure was applied at 70 ° C. for 30 minutes at a pressure of 2.94 MPa. Next, copper was plated by vacuum evaporation to produce a target wiring board substrate. The thickness of the copper plating on the produced wiring board substrate was 20 μm. Further, as a result of measuring the thermal conductivity of the obtained wiring board substrate in the same manner as in Example 1, a high value of 25.27 (W / m · K) was obtained.

(Example 5) The same 3 mm thick plate-like C / C composite as used in Example 1 was brush-coated on one side with Iupirex S (polyimide varnish, trade name: Ube Industries, Ltd.). For 30 minutes to form a polyimide coating film. Subsequently, copper was plated by vacuum evaporation to produce a wiring board substrate. The thickness of the polyimide coating film on the obtained wiring board was 30 μm, and the thickness of the copper plating was 20 μm. The thermal conductivity of the obtained wiring board substrate was measured in the same manner as in Example 1, and as a result, a high value of 20.56 (W / m · K) was obtained.

Example 6 A 20-μm thick Iupitite (model number UPA-N111, trade name) was used as a film-type polyimide adhesive on one side of a plate-like C / C composite having a thickness of 3 mm similar to that used in Example 1. : Ube Industries) 2
Pressing was performed at 50 ° C. for 3 minutes at a pressure of 50 N / cm ² , and subsequently, copper was plated by vacuum evaporation to produce a wiring board substrate. The thickness of the copper plating on the obtained wiring board substrate was 20 μm. The thermal conductivity of the obtained wiring board substrate was measured in the same manner as in Example 1, and as a result, a high value of 20.33 (W / m · K) was obtained.

Example 7 The procedure of Example 2 was repeated, except that a polyimide vapor-deposited polymer layer was formed in a vacuum in place of the polyimide electrodeposition coating film. A substrate was prepared. The thickness of the polyimide vapor-deposited polymer layer in this wiring board substrate was 20 μm. Further, the thermal conductivity of the obtained wiring board substrate was measured in the same manner as in Example 1, and as a result, 20.10 (W / m · K)
I got a high value.

Example 8 Aramid nonwoven fabric having a thickness of 1
20 μm meta-aramid paper (trade name: manufactured by DuPont Teijin Advanced Paper Co., Ltd.)
(Polyimide varnish, trade name: Ube Industries, Ltd.). Subsequently, the nonwoven fabric impregnated with the polyimide varnish was treated in the same manner as in Example 1 with a 3 mm thick plate C /
The laminate was laminated on one side of the C composite and baked at 200 ° C. for 30 minutes to form a polyimide coating film in which the nonwoven fabric was embedded.
Next, copper was plated by vacuum vapor deposition on the polyimide coating film in which the nonwoven fabric was embedded to prepare a wiring board substrate. The thickness of the copper plating on the obtained wiring board substrate is 20 μm.
Met. In addition, as a result of measuring the thermal conductivity of the obtained wiring board substrate in the same manner as in Example 1, 16.
A high value of 53 (W / m · K) was obtained.

Further, in the wiring board substrate of each of the above embodiments, the adhesion between the copper plating as the metal layer and the polyimide coating film and the adhesion between the polyimide coating film and the like and the carbonaceous substrate are simple and convenient. JIS-K-5400
The test was performed according to “8.5.2 Crosscut tape method”.
That is, on the copper plating surface of the wiring board substrate of each example, cuts reaching the carbonaceous substrate through the copper plating and the polyimide coating film thereunder were cut into 22 grids at 1 mm intervals. After the adhesive tape was rubbed with an eraser and adhered to the grid, the adhesive tape was peeled off at once at a right angle to the substrate surface, and the peeling state of the copper plating was visually observed. As a result, no peeling was observed in any of the examples, and high adhesion was exhibited. Further, in order to easily confirm the solder heat resistance of the wiring board substrate, 30 W
Lightly press the soldering iron on the copper plating surface, and apply a solder with 0.8 mm wire diameter to the soldering iron,
When the molten solder was supplied for one minute while flowing onto the copper plating, in any of the examples, the copper plating in the portion where the solder flowed and the peripheral portion thereof showed no problems such as peeling and swelling. Did not.

(Comparative Example) As a comparative example, a printed circuit board No. 31 (thickness: 1.6 mm) was used.
This printed circuit board is obtained by attaching copper foil to both surfaces of a glass-epoxy board. The copper foil on the surface was removed from this printed board by etching to obtain a glass-epoxy board. Next, the obtained glass-epoxy substrate was placed on an aluminum plate (25 mm in thickness), and a thermal conductivity meter QTM-50 was used.
0 (manufactured by Kyoto Electronics Co., Ltd.) to measure the thermal conductivity. The reason for using an aluminum plate here is the same as in each of the above embodiments,
This is because a certain thickness is required for measuring the thermal conductivity. Then, as a result of the measurement, the value of the thermal conductivity was 0.1.
It was only 552 (W / m · K), and the superiority of the wiring board substrate according to the present invention was confirmed.

In measuring the thermal conductivity,
In order to make the thickness approximately the same in each of the above Examples and Comparative Example 1,
In the comparative example, measurement was performed with two substrates stacked. In addition, since the surface of the measurement object needs to be insulated, in each of the above examples, the measurement was performed by covering the surface of the laminate from which the copper foil had been removed with a wrap film (thickness: 10 μm). Also, since the glass-epoxy substrate of the comparative example is insulative, it is not necessary to cover it with a wrap film in the measurement of thermal conductivity,
In order to obtain the same conditions as in the above examples, the measurement was performed by covering with a wrap film.

[0043]

According to the present invention, the thermal conductivity of the substrate itself,
Further, there is provided a wiring board substrate having excellent adhesion between a metal and a substrate and capable of quickly dissipating heat generated as a whole.

The substrate for a wiring board of the present invention can be manufactured at low cost because the carbonaceous material used as the substrate can be obtained at low cost. In addition, since the wiring board substrate of the present invention is made of a lightweight carbonaceous material, electric and electronic devices using the lightweight wiring board substrate can be reduced in weight.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross section of a wiring board substrate according to an embodiment (1).

FIG. 2 is a diagram showing a cross section of a wiring board substrate according to Embodiment (2).

FIG. 3 is a view showing a cross section of a wiring board substrate according to Embodiment (3).

FIG. 4 is a diagram showing a cross section of a wiring board substrate according to Embodiment (4).

FIG. 5 is a diagram showing a cross section of a wiring board substrate according to an embodiment (5).

FIG. 6 is a diagram showing a cross section of a wiring board substrate according to an embodiment (6).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wire board 2 Carbonaceous substrate 21 Carbon matrix 22 Carbon fiber 3 Polyimide coating 4 Metal layer by plating 5 Polyimide film 6 Nonwoven fabric 7 Polyimide vapor deposition polymerization layer

Claims (10)

[Claims] 1. A wiring board substrate comprising a carbonaceous substrate, a polyimide coating provided on the carbonaceous substrate, and a metal layer formed by plating provided on the polyimide coating. 2. A carbonaceous substrate, comprising: a polyimide coating provided on the carbonaceous substrate; a polyimide film provided on the polyimide coating; and a metal layer formed by plating provided on the polyimide film. Wiring board. 3. The wiring board substrate according to claim 1, wherein the polyimide coating film is a polyimide electrodeposition coating film. 4. A wiring board substrate, comprising: a carbonaceous substrate; a polyimide film provided on the carbonaceous substrate; and a metal layer formed by plating provided on the polyimide film. 5. The wiring board substrate according to claim 1, wherein an insulating woven or nonwoven fabric is embedded in the polyimide coating. 6. The wiring board substrate according to claim 2, wherein an insulating woven or nonwoven fabric is buried in the polyimide film. 7. A wiring board substrate comprising a carbonaceous substrate, a polyimide vapor-deposited polymer layer provided on the carbonaceous substrate, and a metal layer formed by plating provided on the polyimide vapor-deposited polymer layer. 8. The wiring board substrate according to claim 1, wherein the plating is plating by vacuum evaporation. 9. The wiring board substrate according to claim 1, wherein the plating is electroless plating. 10. The wiring board substrate according to claim 1, wherein the fine pores of the carbonaceous substrate are impregnated with an inorganic coating agent or a metal.