JPH10215073A - Method for manufacturing multilayer board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve alignment accuracy even if a hydro-type prepreg for pressing is used by arranging a metal foil at both outsides of a fixed object and forming a lamination objet and heating the lamination object by resistance heating by feeding power to the metal foil. SOLUTION: After a prepreg 11 consisting of a thermosetting resin composition and a base is overlapped to the upper and lower surfaces of a plurality of substrates 10 for inner layer, the substrate 10 for an inner layer and the prepreg 11 are fixed by an eyelet pin 20 and a fixed object 30 is formed. Then, a sheet of a metal foil 12 is bent by one end face part of the fixed object 30 and is provided at both outsides of the fixed object 30, thus forming a lamination object consisting of the fixed object 30 and the metal foil 12. Then, with the lamination object, the fixed object 30 is subjected to resistance heating by feeding power to the metal foil 12 via a pressure plate 41 while an area between the pressure plates 41 being provided at both edges of the metal foil 12 is pressed, thus manufacturing a multilayer board where the substrate 10 for the inner layer, the prepreg 11, and the metal foil 12 are formed in one piece.

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 in the manufacture of printed wiring boards used in electric and electronic equipment. This multilayer board is formed by laminating a thermosetting resin composition called a prepreg on a front and back of one or a plurality of inner layer substrates on which a circuit is formed, and laminating a sheet-like adhesive sheet. After laminating the metal foil on the outside and laminating it, sandwich this laminate between flat plates, further sandwich it between the pressing plates of the forming press, heat by the heat from the pressing plates, and pressurize by the pressure between the pressing plates and manufacture Have been.

When manufacturing a multilayer board in which two or more inner-layer substrates are integrated, it is necessary to align circuits formed on the respective inner-layer substrates. 2. Description of the Related Art A method has been conventionally performed in which holes are formed in a substrate for use, a prepreg, a metal foil, and a flat plate, and pins are communicated with the holes to position a circuit formed on the inner layer substrate. However, in the case of this method, it is necessary to pull out the pins after heating and pressurizing, so that there is a problem that productivity and mass productivity are inferior, and a method using eyelets, called mass lamination, has been put to practical use.

[0004] The method using the eyelet pins is a prepreg in which holes for alignment are formed on the upper and lower surfaces of a plurality of inner layer substrates 10 having holes for alignment as shown in FIG. After stacking 11 ..., the inner layer substrate 10
And after driving the eyelet pin 20 having the shaft portion 21 and the flange portion 22 provided at one end of the shaft portion 21 into the positioning hole of the prepreg 11, 20 by tearing and bending the tip of the substrate 20 to form the inner layer substrate 10.
The fixed object 30 is formed by performing positioning and fixing between them.
Next, metal foils 12 and 12 having no holes are arranged on both outer sides of the fixed object 30 to form a laminate. Then, although not shown, the laminate is sandwiched between flat plates without holes and heated and pressed. It is a method of manufacturing.

In order to improve productivity, a plurality of laminates are vertically stacked with a flat plate interposed therebetween as necessary, and the stacked products are heated and pressed by being sandwiched between molding presses. A method of obtaining a large number of multilayer boards at a time, or a method in which a plurality of fixed objects are arranged in a horizontal direction, and a metal foil having a size such that the entire plurality of fixed objects is covered on both outer sides, and then the metal foil A method of sandwiching between flat plates having a size corresponding to the size and then heating and pressurizing to obtain a large number of multilayer plates at once has been studied.

However, when manufacturing a multi-layer board in which a large number of substrates for an inner layer are integrated, when heating and pressing a plurality of laminated products in a vertical direction, or when mounting a plurality of fixed products in a horizontal direction. When heating and pressurization are performed side by side, there is a problem that the shaft portion of the eyelet pin is deformed and the alignment accuracy between the inner layer substrates may be deteriorated.

For this reason, a method for improving the positioning accuracy by reducing the pressure by using an autoclave-type molding press as described in Japanese Patent Application Laid-Open No. H6-177539 has been studied. However, in the case of a method using an autoclave-type forming press, a prepreg for a hydro-type forming press (also referred to as a daylight-type forming press) that is formed by being sandwiched between pressure plates, which is generally used for manufacturing a multilayer board, is used. In such a case, air bubbles remain in the obtained multilayer board and moldability tends to deteriorate, so that it is necessary to use a prepreg having particularly high resin flowability. However, when a prepreg having particularly high resin flowability is used, there is a problem that the thickness of the prepreg has a large variation, and a large number of man-hours are required for processing the resin flow of the obtained multilayer board, resulting in low productivity. . Therefore, even when a prepreg for a hydro-type forming press is used, there is a demand for a method of manufacturing a multilayer plate which has excellent alignment accuracy and can obtain a multilayer plate having excellent moldability.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a plurality of inner layer substrates, a thermosetting resin composition and a base material. After laminating the prepreg made of the material, the inner layer substrate and the prepreg are fixed with eyelets to form a fixed body, and then a metal foil is arranged on both outer sides of the fixed body to form a laminated body, and then the laminated body is formed. A method of manufacturing a multilayer board by heating and pressing a product, and even when using a prepreg for a hydro-type forming press, a multilayer board having excellent alignment accuracy and excellent moldability is obtained. An object of the present invention is to provide a method for producing a multilayer board obtained.

[0009]

According to a first aspect of the present invention, there is provided a method for manufacturing a multilayer board, comprising: stacking a plurality of inner layer substrates, a prepreg comprising a thermosetting resin composition and a base material, A fixed object is formed by fixing the inner layer substrate and the prepreg with eyelets, and then a metal foil is arranged on both sides of the fixed object to form a laminate, and then the laminate is heated and pressed to produce a multilayer. In a method of manufacturing a plate, a method of heating a laminate after forming a laminate by arranging metal foils on both outer sides of the fixed object is performed by bending the metal foil at one end surface of the fixed object. The method is characterized in that a laminate is formed on the outside, a metal foil is supplied with power, and heating is performed by resistance heating.

According to a second aspect of the present invention, in the method for manufacturing a multilayer board according to the first aspect, the method of heating and pressurizing the laminate comprises bending the metal foil at one end of the flat plate. Thereby, a laminate is formed by sandwiching a flat plate between a plurality of laminates so that a metal foil is continuous between adjacent laminates with a flat plate interposed therebetween, and the laminate is heated and
It is a method of applying pressure.

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 metal foil is bent at one end surface of the fixed body. A method of forming a laminate by arranging it on the outside, arranging a plurality of fixed objects flush with each other to form an union fixed object, bending the metal foil at one end surface of the union fixed object and arranging it on both outer sides of the fixed object. It is a method of forming a laminate.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a multilayer board according to any one of the first to third aspects, wherein metal foils are arranged on both outer sides of the fixed object. Is a method of disposing a second prepreg composed of a thermosetting resin composition and a base material outside a fixed object, and further disposing a metal foil outside the second prepreg.

According to the present invention, since the entire metal foil generates heat, compared with the method of heating by heat transfer from the pressure plate,
The prepreg is rapidly heated, and the thermosetting resin composition in the prepreg is rapidly cured. Therefore, it is considered that the time during which the thermosetting resin composition is melted becomes shorter, and the displacement between the inner layer substrates due to the flow of the melted thermosetting resin composition is reduced.

Further, since all the thermosetting resin compositions are melted at substantially the same time, the in-plane distribution of the pressure applied to each laminate is uniform as compared with the method of heating by heat transfer from the pressure plate. Become Therefore, even when the prepreg for the hydro-type forming press is used with a reduced pressure, it is possible to obtain a multilayer plate having excellent moldability,
It is considered that the displacement between the inner layer substrates due to the pressurization is reduced, and a multilayer board having excellent alignment accuracy and excellent moldability is obtained.

[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 view for explaining one embodiment of a method for manufacturing a multilayer board according to the present invention. FIG. 2 is a diagram illustrating another embodiment of the method for manufacturing a multilayer board according to the present invention. FIG. 3 is a view for explaining still another embodiment of the method for manufacturing a multilayer board according to the present invention.

As shown in FIG. 1, one embodiment of a method for manufacturing a multilayer board according to the present invention is a method of manufacturing a plurality of substrates 10 for an inner layer.
After the prepregs 11 consisting of a thermosetting resin composition and a base material are laminated on the upper and lower surfaces of
.. and prepregs 11... Are fixed with eyelets 20 to form fixed objects 30. Next, one metal foil 12 is disposed on both outer sides of the fixed object 30 by bending the metal foil 12 at one end surface of the fixed object 30, and the fixed object 30 and the metal foil 12 are arranged.
Forming a laminate comprising

In this embodiment, the two laminates are:
The laminates are vertically stacked with an insulating flat plate 40 interposed therebetween, and the metal foil 12 is bent at one end surface of the flat plate 40 interposed therebetween, so that the adjacent laminates sandwich the flat plate 40 therebetween. The metal foil 12 is made continuous between them. It is preferable to manufacture a plurality of laminates by stacking them in the vertical direction, because a large number of multilayer boards can be obtained by a single heating and pressurization.

The method for fixing the inner layer substrates 10 and the prepreg 11 with the eyelets 20 is not particularly limited. For example, the upper surfaces of a plurality of inner layer substrates 10 with holes for positioning are fixed. And prepregs 11 with holes for positioning on the lower surface are stacked, and then the holes for positioning the inner layer substrate 10 and the prepreg 11 are
By driving an eyelet 20 made of brass or the like formed of a shaft portion and a flange portion provided at one end of the shaft portion and bringing the flange portion into contact with the prepreg 11, the tip portion of the shaft portion is torn and bent. In short, the inner layer substrate 10
Alignment between the substrates and fixing of the inner layer substrate 10 and the prepreg 11 are performed.

The eyelet pin 20 is not limited to the above-described structure. For example, the eyelet pin 20 may be fixed by driving a cylindrical eyelet pin 20 and then tearing and bending both ends thereof, or by using a stapler pin. It may be something.

Next, the laminate is heated and pressed to produce a multilayer board. As a method, for example, as shown in FIG.
The laminate is sandwiched between metal pressing plates 41 of a forming press, with an insulating flat plate 40 interposed therebetween as required. Next, after both ends of the metal foil 12 are connected to the one pressing plate 41 and the other pressing plate 41, power is supplied to the metal foil 12 via the pressing plate 41 in a state where the pressure between the pressing plates 41, 41 is pressed. . Then, the fixed object 30 is heated by resistance heating.

Due to the curing reaction of the prepreg 11 by the heating and the pressure applied between the pressure plates 41, the inner layer substrate 10, the prepreg 11 and the metal foil 12 are integrated to obtain a multilayer plate. 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 voltage and current to be supplied may be appropriately adjusted so that the thermosetting resin composition in the prepreg 11 is cured.

In the case of this method of heating by resistance heating,
Since the entire metal foil 12 generates heat, the prepreg 11 is rapidly heated and the thermosetting resin composition in the prepreg 11 is rapidly cured as compared with the method of heating by heat transfer from the pressure plate. Therefore, the time required for the thermosetting resin composition to melt is shortened, the displacement between the inner layer substrates 10... Due to the flow of the melted thermosetting resin composition is reduced, and a multilayer board having excellent alignment accuracy is obtained. It is thought that it can be obtained.

Further, since the resin composition is melted at substantially the same time, the in-plane distribution of the pressure applied to each of the laminates becomes uniform as compared with the method of heating by heat transfer from the pressure plate. Therefore, even when the prepreg for the hydro-type molding press is used at a reduced pressure, a multilayer plate excellent in moldability can be obtained, and the inner-layer substrate 10. It is considered that the misalignment is reduced, and a multilayer board having excellent alignment accuracy and excellent moldability can be obtained.

When the laminate is sandwiched between pressure plates,
If necessary, heating and pressing may be performed with a cushion material such as cellulose paper or aramid fiber paper, a heat conduction adjusting material, etc. interposed therebetween.

The method of manufacturing a multilayer board is not limited to the method of manufacturing a plurality of stacked layers in the vertical direction as described above, but may be a single stacked body. In this case as well, a multilayer board having excellent alignment accuracy can be obtained. In the case where one multilayer board is to be manufactured by integrating a large number of inner layer substrates 10, it is preferable that the number of stacked layers be small, because the alignment accuracy of the obtained multilayer board is excellent.

As shown in FIG. 2, a plurality of fixed objects 30 are arranged in a horizontal plane to form an associated fixed object, and the metal foil 12 is bent at one end face of the fixed object to fix the fixed object 3.
The metal foils 12 may be arranged on both outer sides of 0 to form a laminate. In this case, too, a large number of multilayer boards can be obtained with a single heating and pressing step, which is preferable. In addition, the `` flush '' of the present invention is not limited to exactly the flush state, as long as the obtained multilayer board is in a range where the multilayer board is formed flush.
Some variation is allowed.

As shown in FIG. 3, a second prepreg 11b made of a thermosetting resin composition and a base material is provided outside the fixed object 30, and a metal foil is provided outside the second prepreg 11b. 12 may be arranged to form a laminate. In this case, the pressure applied to the portion corresponding to the eyelets 20 of the flat plate 40 sandwiched between the laminates is reduced,
This is preferable because unevenness hardly occurs on the flat plate 40.

The types of the prepreg (first prepreg 11a) and the second prepreg 11b in the fixed object 30 may be the same or different. Further, the second prepreg 11b is located at a position corresponding to the eyelet pin 20,
Holes may or may not be drilled. It is preferable that a hole is formed at a position corresponding to the eyelet pin 20, since pressure applied to a portion corresponding to the eyelet pin 20 is particularly relieved, and unevenness of the flat plate 40 is hardly generated, which is preferable. In addition, it is preferable that a hole is not formed at a position corresponding to the eyelet pin 20 because wrinkles are hardly generated in the metal foil 12 at a position corresponding to the eyelet pin 20.

In the above embodiment, the prepreg 11 is arranged and fixed on the surface of the fixed object 30. However, the prepreg 1 is fixed on the surface of the fixed object 30.
However, the present invention is not limited to the case where the first prepreg 11b is provided, and the case where the metal foil 12 is not bonded to the surface of the multilayer board to be obtained or the case where the second prepreg 11b is arranged outside the fixed object 30 The inner layer substrate 10 may be arranged on the surface of the fixed object 30.

The substrate 10 for the inner layer used in the present invention is not particularly limited as long as it is a plate provided with a conductor circuit. For example, an epoxy resin, a phenol resin, a polyimide resin, and an unsaturated polyester resin are used. , Thermosetting resins such as polyphenylene ether resin, etc., and boards made by mixing these thermosetting resins with inorganic fillers, inorganic fibers such as glass, cloths of organic fibers such as polyester, polyamide, cotton, paper, etc. A substrate in which a conductive circuit is formed on a plate obtained by bonding the above base material with the above-described thermosetting resin or the like. The position where the conductive circuit is formed may be on the surface or inside. Further, the inner layer substrate 10 may have a hole in which a metal film is formed on the wall surface.

Prepregs 11, 11 used in the present invention
a and 11b are composed of a thermosetting resin composition and a base material. For example, after a solvent is added to the thermosetting resin composition to adjust the viscosity, the base material is immersed in the liquid to impregnate the liquid. And
Next, the solvent is dried by heating to obtain a thermosetting resin composition that is semi-cured, or a solid thermosetting resin composition that is heated and melted at room temperature is applied to a substrate and impregnated. It is obtained by doing.

As the base material, 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. Note that a woven fabric (glass cloth) made of glass fiber is preferable because of its excellent heat resistance and moisture resistance. The thickness of the substrate is generally 40 to 300 μm.

The thermosetting resin composition may be a thermosetting resin composition such as an epoxy resin, a phenol resin, a polyimide resin, an unsaturated polyester resin, a polyphenylene ether resin alone, a modified product, or a mixture. Any of the conductive resin compositions can be used. 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 for 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 11 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 12 used in the present invention is not particularly limited as long as it is a conductive foil, and may be a single, alloy, or composite foil of copper, aluminum, brass, nickel, or the like. Can be. The thickness of the metal foil 12 is generally 0.012 to 0.070 mm. Note that a layer of a thermosetting resin composition may be formed on one surface of the metal foil 22.

[0037]

【Example】

(Example 1) As a material of the multilayer board, a size of 51 × 34c was used.
m, 0.2 mm-thick glass substrate epoxy resin double-sided copper-clad laminate excluding copper foil [R-1 manufactured by Matsushita Electric Works, Ltd.
766] is etched, and an epoxy resin composition is impregnated into a substrate for an inner layer in which a copper circuit having a land with a diameter of 2 mm is formed on a surface and a glass cloth, and then dried and semi-cured. Prepreg [manufactured by Matsushita Electric Works Co., Ltd., trade name: R1661, 0.2 mm thick] and a copper foil having a thickness of 18 µm were used.

Then, a positioning hole having a diameter of 5 mm was formed in the inner layer substrate and the prepreg. Then, after each prepreg having a hole for alignment on each of the upper and lower surfaces of the two substrates for inner layer having holes for alignment, one prepreg is provided, and then the substrate for alignment with the inner layer and the prepreg for alignment are prepared. An eyelet pin made of brass was driven into the hole, and the eyelet pin was torn and bent to form a fixed object by aligning the inner layer substrate and fixing the inner layer substrate and the prepreg. The eyelet pin has an outer diameter of 5
An eyelet pin having a cylindrical shaft portion having a diameter of 4.3 mm and an inner diameter of 4.3 mm and a flange portion was used.

Next, the displacement between the two inner-layer substrates in each fixed object was determined by using the copper circuit formed on the inner-layer substrate with a diameter of 2 m.
The land portion of m was obtained by X-ray observation.

Next, ten sets of laminates in which a long copper foil was bent at one end face of the fixed object and superposed on the front and back of the fixed object were interposed between flat plates (a plate in which the surface of aluminum was insulated,
(Thickness: 2 mm) was interposed, and the same flat plate was stacked on both sides of the stacked product, and then sandwiched between metal pressing plates of a forming press. In addition, the copper foil arranged on the front and back of the fixed object was arranged such that the copper foil was continuous even between adjacent laminates with a flat plate interposed therebetween.

Next, a copper foil was supplied with power between the pressure plates under the condition that the pressure per unit area of the laminate was 1 MPa, and the laminate was heated at 170 ° C. for 60 minutes by resistance heating to produce a multilayer plate. did.

(Example 2) Two sets of fixed objects are arranged in a plane to form an associated fixed object, and a copper foil is bent at one end of the associated fixed object and copper foils are arranged on both outer sides of the fixed object and laminated. A multilayer board was manufactured in the same manner as in Example 1 except that a product was formed and a flat plate having a size corresponding to the size of the fixed fixture was used.

(Embodiment 3) A hole 2 for positioning was formed.
A prepreg having a hole for alignment between two inner layer substrates is sandwiched between the prepregs and fixed with eyelets to form a fixed body. Then, a prepreg without a hole (a second prepreg) is placed on both sides thereof. After that, a multilayer board was manufactured in the same manner as in Example 1 except that the copper foil was bent at one end surface of the stacked product and the stacked product was formed on the front and back surfaces of the stacked product.

(Comparative Example 1) Ten sets of laminates in which sheet-like copper foils were respectively laminated on the front and back of a fixed object were laminated with a flat plate (stainless steel plate, 2 mm thick) interposed therebetween, and both sides of the laminated product After the same flat plate is stacked, it is sandwiched between pressure plates of a hydro-type forming press, and the pressure plate is heated while pressing the pressure plates under a condition that the pressure per unit area of the laminate is 3 MPa. Thus, a multilayer board was manufactured in the same manner as in Example 1 except that heat was transferred to the laminate and heated at 170 ° C. for 90 minutes.

(Comparative Example 2) Two sets of fixed objects were arranged side by side to form an union fixed object, and sheet-like copper foils corresponding to the size of the union fixed object were respectively superposed on the front and back, and the union was formed. A multilayer board was manufactured in the same manner as in Comparative Example 1 except that a flat plate having a size corresponding to the size of the fixed object was used.

(Comparative Example 3) A multilayer board was manufactured in the same manner as in Comparative Example 1 except that pressure was applied between the pressure plates under the condition that the pressure per unit area of the laminate was 1 MPa.

(Evaluation and Results) The positioning accuracy and formability of the multilayer boards obtained in each of the examples and comparative examples and the occurrence of unevenness of the flat plates used in each of the examples were evaluated. The positioning accuracy of the multilayer board is obtained by observing the positional shift between the two inner layer substrates in the multilayer board by X-ray observation, and determining the difference from the value obtained by evaluating the fixed body before heating and pressing. The maximum value of the five sheets was determined as the value of the alignment accuracy. The moldability of the multilayer plate was determined by etching the outermost copper foil and then visually observing the presence of air bubbles inside the multilayer plate. O was evaluated when there were no air bubbles, and X was evaluated when air bubbles were present. The state of unevenness of the flat plate is determined by touching the unevenness of the part corresponding to the eyelet pin of the flat plate,
The case where no unevenness was felt was evaluated as ○, and the case where unevenness was felt was evaluated as x.

As shown in Table 1, the results confirmed that the examples had better alignment accuracy than the comparative examples. In addition, it was confirmed that each example had better moldability than Comparative Example 3 in which the same pressure was applied.

The third embodiment, in which the second prepreg is disposed outside the fixed object and the copper foil is disposed outside the second prepreg 11b, has a flat plate shape compared to the first and second embodiments. It was confirmed that the occurrence of irregularities was small.

[0050]

[Table 1]

[0051]

According to the method for producing a multilayer board of the present invention, since the metal foil is supplied with power and heated by resistance heating, a multilayer board having excellent alignment accuracy and excellent moldability can be obtained.

According to the method for manufacturing a multilayer board of the present invention, in addition to the above-described effects, unevenness is less likely to occur on the flat plate used at the time of manufacture.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of a method for manufacturing a multilayer board according to the present invention.

FIG. 2 is a diagram illustrating another embodiment of the method for manufacturing a multilayer board according to the present invention.

FIG. 3 is a view for explaining still another embodiment of the method for producing a multilayer board according to the present invention.

FIG. 4 is a cross-sectional view illustrating a conventional method for manufacturing a multilayer board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Inner-layer board 11 Prepreg 12 Metal foil 20 Eyelet pin 21 Shaft part 22 Flange part 30 Fixed object 40 Flat plate

Claims (4)

[Claims] 1. A prepreg (11) comprising a plurality of inner layer substrates (10...), A thermosetting resin composition and a base material
After that, the inner layer substrate (10...) And the prepreg (11) are fixed with eyelets (20) to fix the fixed object (3).
0) is formed, and then a metal foil (12) is arranged on both outer sides of the fixed object (30) to form a laminate. Then, the laminate is heated and pressed to produce a multilayer board. ,
After the metal foil (12) is arranged on both outer sides of the fixed object (30) to form a laminate, the method of heating the laminate is such that the metal foil (12) is bent at one end of the fixed object (30). A method for producing a multilayer board, comprising forming a laminate by disposing the laminate on both outer sides of the fixed object (30), supplying power to the metal foil (12), and heating by resistance heating. 2. A method of heating and pressurizing a laminate by bending a metal foil (12) at one end surface of a flat plate (40) so that a metal foil is sandwiched between adjacent laminates with a flat plate (40) interposed therebetween. The method of forming a laminate by stacking a flat plate (40) between a plurality of laminates so that (12) is continuous, and heating and pressing the laminate. 2. The method for producing a multilayer board according to 1. 3. A method of forming a laminate by folding a metal foil (12) at one end face of a fixed object (30) and disposing the metal foil (12) on both outer sides of the fixed object (30) is performed. A method of forming a joint by arranging a plurality of joints at a time, bending a metal foil (12) at one end face of the joint and disposing the metal foil on both outer sides of the fixture (30). The method for producing a multilayer board according to claim 1 or 2, wherein 4. A metal foil (1) on both outer sides of the fixed object (30).
The method of disposing 2) is such that the second prepreg (11) comprising the thermosetting resin composition and the base material is provided outside the fixed object (30).
4. The method according to claim 1, further comprising the step of disposing a metal foil (12) outside the second prepreg (11b). Production method.