JPH11214843A - Manufacture of multilayer board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fabricate an intermediate body wherein prepregs and a substrate for an inner layer are bonded into an integral unit, by putting a united substrate made by connecting a plurality of substrates in parallel for an inner layer in the horizontal direction between the prepregs constituted of a thermosetting resin composition and a basic material to form the intermediate body, then placing metal foils on both sides of the intermediate body to form a pressurized body, and then heating and pressurizing the pressurized body. SOLUTION: A substrate 11 for an inner layer is made by bonding basic materials with thermosetting resin and the like such as epoxy resin unsaturated polyester resin and then a conductor circuit is formed on the board. As a method for fabricating a prepreg 12, a solvent is added into a thermosetting resin composition and the viscosity of the liquid is adjusted and then a basic material is dipped in the liquid to impregnate the basic material with the liquid, and after that, the basic material is heated to dry the solvent and half-harden the thermosetting resin composition and thus the prepreg 12 is fabricated. For the basic material, inorganic fiber such as glass, polyester and the like, or unwoven cloth or paper can be used. The united substrate 10 and the prepregs 12 are so stacked that the prepregs 12 may be brought into contact with both faces of the united substrate 10 and these are stuck to each other with a sticking agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer board used for electric / electronic equipment and the like.

[0002]

2. Description of the Related Art Multilayer boards are used for manufacturing printed wiring boards used for electric and electronic equipment. The multilayer board is formed by impregnating a base material with a thermosetting resin composition called a prepreg on one or a plurality of inner layer substrates on which a conductive circuit is formed, and laminating a sheet-like adhesive sheet. After metal foils are arranged on both outer sides and stacked to form a body to be pressed, the body to be pressed is sandwiched between flat plates, further sandwiched between pressing plates of a forming press, and heated by heat transfer from the pressing plates. It is manufactured by applying pressure between the pressure plates.

[0003] In order to improve the productivity, as shown in FIG. 3, a combined substrate 10 in which a plurality of inner layer substrates 11... Are arranged in a horizontal direction is several times the size of the inner layer substrate 11. After the prepreg 12 is sandwiched between the prepregs 12 and overlaid, a metal foil 13 sized to cover the entire prepreg 12 is disposed on both outer sides of the prepreg 12 to form a body 14 to be crimped.
3 and a pressing plate 19 having a size corresponding to the size of the flat plate 18.
19, a method of obtaining a large number of multilayer boards at a time by heating and pressurizing, or a method of stacking a plurality of the pressure-bonded members 14 in a vertical direction with a flat plate 18 interposed therebetween, 1
A method of obtaining a large number of multi-layer boards at a time by heating and pressurizing the sheets between the layers 9 and 19 is performed.

The substrate 11 for the inner layer, the prepreg 1
2, the metal foil 13 and the flat plate 18 are stacked one on top of the other from the lower one to the upper one. For example, in the case of the configuration of FIG.
A metal foil 13 on top of it, and then prepreg 1
After the required number of sheets 2 are stacked, a plurality of inner layer substrates 11 are horizontally arranged thereon, and then the required number of prepregs 12 are stacked thereon, and then the metal foil 13 is stacked thereon. So that the flat plate 18 is placed on the lower pressing plate 1
A method of sequentially stacking portions from a portion corresponding to 9 to a portion corresponding to the upper pressure plate 19 is performed.

However, in the case of a method of arranging a plurality of inner layer substrates 11 on the prepreg 12 while arranging a plurality of them, there is a problem that it takes a long time to overlap the whole, and the productivity is low. For this reason, an intermediate body is formed in advance, in which a plurality of inner-layer substrates 11 are arranged in a horizontal direction, and an assemblage substrate 10 is sandwiched between prepregs 12, and the intermediate body is sandwiched between metal foils 13 and stacked. A method for forming the press-bonded body 14 has been studied.

However, in the multilayer board obtained by the method using this intermediate, a fine cured product of a thermosetting resin may be formed on the metal foil 13 on the surface in some cases. This is because the thermosetting resin composition in the prepreg 12 is generally brittle because it is in a semi-cured state (B-stage state), and when a large force is applied to the prepreg 12 during handling or the like, the resin is broken, and the resin May be peeled off from the prepreg 12, and the resin may be cracked or the prepreg 1 may be peeled off.
When a multilayer board is to be manufactured using the method 2, the resin powder is scattered during the operation and adheres to the metal foil 13, so that a cured product of the resin is formed on the metal foil 13 on the surface of the obtained multilayer board. It is considered.

Since the inner layer substrate 11 is generally harder and heavier than the prepreg 12, as shown in FIG. 2 (b), when the substrate 15 is transported by holding both ends of the intermediate body 15, the inner layer substrate 11, 11 Prepreg 12 in the part between
Is easy to bend and the resin in that part is easily broken.
As compared with the case where two inner layer substrates 11 are used, a cured product of a thermosetting resin is easily formed.

When a conductive circuit is formed by etching the surface metal foil using a multilayer board in which a cured product of a thermosetting resin is formed on the metal foil on the surface, a cured product of the thermosetting resin is formed. There is a problem that the printed portion is likely to be short-circuited and the yield of the printed wiring board is low. for that reason,
There is a need for a method of manufacturing a multilayer board in which a cured product of a thermosetting resin is not easily formed on a metal foil on the surface of the obtained multilayer board.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a combined substrate in which a plurality of inner layer substrates are arranged in a horizontal direction. After forming an intermediate body by sandwiching and sandwiching between a prepreg composed of a thermosetting resin composition and a base material, metal foils are arranged on both outer sides thereof to form a body to be compressed, and then the body to be compressed is formed. A method of manufacturing a multilayer board manufactured by heating and pressing,
An object of the present invention is to provide a method for manufacturing a multilayer board in which a cured product of a thermosetting resin is less likely to be formed on a metal foil on the surface of the obtained multilayer board.

[0010]

According to a first aspect of the present invention, there is provided a method for manufacturing a multilayer board, comprising: forming an associated substrate in which a plurality of inner layer substrates are arranged in a horizontal direction from a thermosetting resin composition and a base material. After forming an intermediate by sandwiching it between prepregs
A metal foil is disposed on both outer sides to form a body to be pressed, and then, in a method of manufacturing a multilayer board manufactured by heating and pressing the body to be pressed, a combined substrate is sandwiched between prepregs and overlapped. The method of forming the body, after overlapping the prepreg and the prepreg so that the prepregs are in contact with both sides of the association board,
This is a method in which a thermosetting resin composition in a prepreg is melted, and then the thermosetting resin composition is melted and pressed between pressure rolls, and then the thermosetting resin composition is solidified. It is characterized by the following.

[0011] According to a second aspect of the present invention, in the method for manufacturing a multilayer board according to the first aspect, the method for solidifying the thermosetting resin composition comprises the step of applying cooled air to the surface of the prepreg. It is a method of spraying.

According to a third aspect of the present invention, there is provided a method for manufacturing a multilayer board according to the first or second aspect, wherein the temperature of the pressure roll is adjusted to the thermosetting resin composition in the prepreg. Is a temperature at which the solidification occurs.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a multilayer board according to any one of the first to third aspects, wherein a fluororesin layer is formed on the surface of the pressure roll. It is characterized by being formed.

According to the present invention, the prepreg and the substrate for the inner layer are bonded and integrated into an integrated body by the solidified thermosetting resin composition after being melted. Even in the case where the prepreg is hardly bent at the portion between the arranged inner layer substrates, the powder of the thermosetting resin composition is hardly scattered, and the surface of the multilayer board obtained using this intermediate is A cured product of a thermosetting resin is not easily formed on the metal foil.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a multilayer board according to the present invention will be described with reference to the drawings. FIG. 1 is a front view illustrating one embodiment of a method for manufacturing a multilayer board according to the present invention. FIG.
FIG. 3A is a diagram illustrating a state of transporting an intermediate, FIG. 3A is a front view illustrating an embodiment of a method for manufacturing a multilayer board according to the present invention, and FIG. It is a front view explaining the case of a method. FIG. 3 is an exploded front view illustrating an embodiment of the method for manufacturing a multilayer board according to the present invention.

As shown in FIG. 3, one embodiment of the method for manufacturing a multilayer board according to the present invention is a method for manufacturing a plurality of inner-layer substrates 11.
Are combined with the prepreg 12
··· After forming the intermediate body 15 by being sandwiched between them, the metal foils 13 are arranged on both outer sides thereof to form the crimped body 14, and then the crimped body 14 is heated and pressed to produce This is a method for producing a multilayer board.

The inner layer substrate 11 used in the present invention includes:
The board is not particularly limited as long as it is a board on which a conductor circuit is formed.For example, thermosetting resins such as epoxy resin, phenol resin, polyimide resin, unsaturated polyester resin, polyphenylene ether resin, and the like, A board in which an inorganic filler or the like is blended in a curable resin, a board in which inorganic fibers such as glass, cloth of organic fibers such as polyester, polyamide, and cotton, and a base material such as paper are bonded with the thermosetting resin or the like. In addition, there is one in which a conductor circuit is formed. The position where the conductive circuit is formed may be on the surface or inside. Further, the inner layer substrate 11 may have a hole in which a metal film is formed on a wall surface thereof. It should be noted that the inner layer substrates 11 arranged in a horizontal direction to form the associated substrate 10 generally have the same thickness, but may have slightly different thicknesses.

The prepreg 12 used in the present invention comprises a thermosetting resin composition and a base material. For example, after adjusting the viscosity by adding a solvent to the thermosetting resin composition,
The base material is immersed in the liquid to be impregnated, and then heated to dry the solvent to obtain a semi-cured thermosetting resin composition, or to heat a solid thermosetting resin composition at room temperature. It is obtained by applying and impregnating a substrate in a molten state. In addition, the thermosetting resin composition in the prepreg 12 is limited to a semi-cured (B stage) state.

As the substrate, woven fabric, non-woven fabric, paper and the like of inorganic fibers such as glass, organic fibers such as polyester, polyamide, polyacryl, and polyimide, and natural fibers such as cotton can be used. In addition, it is preferable to use a woven fabric (glass cloth) made of glass fiber because a multilayer board having excellent heat resistance and moisture resistance can be obtained. In addition, the thickness of the base material is 0.1.
Those having a diameter of 04 to 0.30 mm are generally used.

Further, the thermosetting resin composition includes:
The entire thermosetting resin composition can be used, such as an epoxy resin-based, phenolic resin-based, polyimide resin-based, unsaturated polyester resin-based, polyphenylene ether resin-based alone, modified product, or mixture. In addition, when a thermosetting resin composition is an epoxy resin type | system | group, the balance of an electrical property and adhesiveness is favorable and it is preferable.

The thermosetting resin composition contains a thermosetting resin as an essential component and, if necessary, a curing agent, a curing accelerator, an inorganic filler, a solvent and the like of the thermosetting resin. be able to. A thermosetting resin composition having a low self-curing property, such as an epoxy resin, needs to contain a curing agent for curing the resin.

The amount of the thermosetting resin composition in the prepreg 12 is preferably 40 to 70 parts by weight based on 100 parts by weight of the total weight of the thermosetting resin composition and the base material. 40
If the amount is less than 10 parts by weight, bubbles may remain inside the obtained multilayer board and the electrical characteristics may be reduced. If the amount is more than 70 parts by weight, the thickness of the obtained multilayer board may vary greatly. There is.

The metal foil 13 used in the present invention is not particularly limited as long as it is a metal foil.
A single, alloy, or composite foil of copper, aluminum, brass, nickel, or the like can be used. The thickness of the metal foil 13 is generally 0.012 to 0.070 mm.
Note that a layer of the thermosetting resin composition may be formed on one surface of the metal foil 13. In this case, lamination is performed so that the layer of the thermosetting resin composition is in contact with the prepreg 12.

In the case where the intermediate 15 is formed,
As shown in FIG. 1, prepreg 1
The associated substrate 10 and the prepreg 12 are overlapped such that the two are in contact with each other (hereinafter, the overlapped substrate is referred to as a substrate prepreg load). Note that a plurality of inner layer substrates 11
It is preferable to bond the end surfaces with an adhesive or to connect the surfaces with an adhesive tape to form the associated substrate 10 by fixing with a fixed substance, so that the substrate prepreg load can be easily transported when it is transported.

Next, the substrate prepreg loaded material is heated by the heater 22 while being conveyed by the net conveyor 21 to melt the thermosetting resin composition in the prepreg 12, and then the thermosetting resin composition is melted. The molten thermosetting resin composition is solidified by blowing cooled air from the air nozzle 24 onto the surface of the prepreg 12 after pressurizing the molten state between the pressure rolls 23 and 23 in the molten state.

Then, the prepreg 12 and the inner layer substrate 1 are melted and solidified by the thermosetting resin composition.
1... Are bonded to form an integrated intermediate body 15. Therefore, as shown in FIG. 2A, even when the intermediate body 15 is transported with both ends held, the prepreg 12 is less likely to be bent at the portion between the inner layer substrates 11, 11 arranged. As compared with the case as shown in FIG. 2B, the powder of the thermosetting resin composition is less likely to be scattered, and the metal foil 13 on the surface of the multilayer board obtained by using the intermediate 15
It becomes difficult to form a cured product of the thermosetting resin.

Further, after the thermosetting resin composition is melted and solidified, the powder of the thermosetting resin composition adhering to the cut surface of the prepreg 12 is taken into the prepreg 12. Also, the scattering caused by the powder of the thermosetting resin composition adhered to the cut surface and the like is reduced, and the cured product of the thermosetting resin is less likely to be formed on the metal foil on the surface of the obtained multilayer board. .

The method of melting the thermosetting resin composition in the prepreg 12 is not particularly limited as long as it can be heated to a temperature at which the thermosetting resin composition in the prepreg 12 melts. Examples thereof include a method of heating with a heater and the like, a method of blowing heated air, and the like.

The method of solidifying the thermosetting resin composition is not particularly limited as long as it can be cooled to a temperature at which the thermosetting resin composition in the prepreg 12 solidifies. , A method of blowing room temperature or cooled air, a method of leaving the material to cool, and the like. Note that a method of blowing cooled air onto the surface of the prepreg 12 is preferable because it has a high cooling efficiency and can be solidified in a short time.

The pressure rolls 23, 23 for applying pressure in a state where the thermosetting resin composition is melted, can be pressurized with the substrate prepreg loaded with the melted thermosetting resin composition in the prepreg 12 interposed therebetween. The roll is not particularly limited as long as it is a suitable roll, and examples thereof include a roll of silicon rubber. The temperature of the pressure roll 23 may be a temperature at which the thermosetting resin composition in the prepreg 12 is melted.
The solidification temperature may be used, but in the case of the solidification temperature, the viscosity of the thermosetting resin composition in a portion in contact with the pressure roll 23 increases, and the pressure applied between the pressure rolls 23 and And prepreg 12
This is preferable because the bonding between the associated substrate 10 and the prepreg 12 is more reliable.

When a layer having excellent releasability with respect to a thermosetting resin composition such as a fluororesin is formed on the surface of the pressure roll 23, the surface of the pressure roll 23 is cured by heat. This is preferable because the conductive resin composition does not easily adhere thereto.

FIG. 1 shows an embodiment in which the intermediate body 15 is formed by heating or cooling from one side of the substrate prepreg load, but the intermediate body 15 is formed on both sides of the substrate prepreg load. Alternatively, heating or cooling may be performed.

Then, as shown in FIG. 3, the intermediate body 15 formed as described above is
After forming 4, the crimped body 14 is sandwiched between flat plates 18, and the stacked ones are sandwiched between pressing plates 19, 19, and heated and pressed to produce a multilayer board. Examples of the method of heating and pressurizing include a method of heating the pressurizing plate 19 and heating by the heat transfer from the pressurizing plate 19, and a method of supplying power to the metal foil 13 and heating it by resistance heating. Note that resistance heating is a method in which power is supplied to a conductor having electric resistance and heating is performed using heat generated by the Joule effect. The heating conditions may be appropriately adjusted so that the thermosetting resin composition in the prepreg 12 is cured. Examples of the flat plate 18 used in the present invention include a metal plate such as iron and stainless steel or a plate obtained by insulating the surface of these metal plates.

When the object 14 is sandwiched between the flat plates 18 and sandwiched between the pressure plates 19, a cushion material such as cellulose paper or aramid fiber paper or a heat conduction adjusting member may be used as necessary. Heating and pressing may be performed with a material or the like interposed therebetween.

In the above embodiment, the prepreg 12
Although the embodiment in which the intermediate body 15 is formed with one association substrate 10 interposed therebetween has been described, the number of association substrates 10 is not limited to one, and a plurality of associations with the prepreg 12 interposed therebetween. The substrates 10 may be stacked in the vertical direction, and the prepregs 12 may be arranged on both outer sides to form the intermediate body 15. Further, the number of the pressure-bonded members 14 sandwiched between the pressure plates 19 is not particularly limited, and may be one or plural.

[0036]

According to the method for manufacturing a multilayer board of the present invention, an intermediate body can be formed by bonding a prepreg and an inner layer substrate with a thermosetting resin composition that has been melted and then solidified. Therefore, it is difficult to form a cured product of the thermosetting resin on the metal foil on the surface of the obtained multilayer board.

[Brief description of the drawings]

FIG. 1 is a front view illustrating one embodiment of a method for manufacturing a multilayer board according to the present invention.

FIGS. 2A and 2B are diagrams illustrating a state of transporting an intermediate, wherein FIG. 2A is a front view illustrating an embodiment of a method for manufacturing a multilayer board according to the present invention, and FIG. It is a front view explaining the case of the manufacturing method of a board.

FIG. 3 is an exploded front view for explaining one embodiment of the method for manufacturing a multilayer board according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Union board 11 Substrate for inner layer 12 Prepreg 13 Metal foil 14 Body to be crimped 15 Intermediate body 18 Flat plate 19 Press plate 21 Net conveyor 22 Heater 23 Press roll 24 Air nozzle

Claims (4)

[Claims] 1. An intermediate body formed by stacking a plurality of inner layer substrates arranged in a horizontal direction and sandwiching them between a prepreg made of a thermosetting resin composition and a base material to form an intermediate body. In a method of manufacturing a multilayer board, in which a metal foil is arranged on a metal foil and then the body to be pressed is heated and pressed, an intermediate body is formed by sandwiching the associated substrates between prepregs and stacking them. The method is such that after the prepreg is overlapped with the prepreg so that the prepregs are in contact with both surfaces of the associated substrate, the thermosetting resin composition in the prepreg is melted, and then the thermosetting resin composition is added in a molten state. A method for producing a multilayer board, which is a method of solidifying the thermosetting resin composition after being pressed between pressure rolls. 2. The method according to claim 1, wherein the method of solidifying the thermosetting resin composition is a method of blowing cooled air onto the surface of the prepreg. 3. The method according to claim 1, wherein the temperature of the pressure roll is a temperature at which the thermosetting resin composition in the prepreg is solidified. 4. The pressure roller according to claim 1, wherein a layer of a fluororesin is formed on a surface of the pressure roll.
The method for producing a multilayer board according to any one of the above.