JP5585035B2 - Circuit board manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a circuit board, and more particularly to a method for manufacturing a circuit board in which a built-up layer made of a prepreg sheet is laminated on a core layer.

  In recent years, with the reduction in size and weight of electronic devices, there is a demand for reduction in size, weight, and thickness of circuit boards used in electronic devices. Therefore, a circuit board having a new structure and a manufacturing method thereof have been developed. For example, Patent Document 1 discloses a method of manufacturing a circuit board using a prepreg sheet as a base material of the circuit board.

  In the method for manufacturing a circuit board disclosed in Patent Document 1, a film is laminated on both sides of a prepreg sheet that is made into a non-cured state by impregnating a woven cloth having a thickness of 0.06 mm or less with a thermosetting resin. Is provided with a through hole. After filling the through hole with conductive paste, peel the film from the prepreg sheet, press and heat the prepreg sheet with the metal foil attached to the surface where the film was peeled off, and pattern the metal foil to form a wiring pattern It is.

JP 2005-44988 A

  However, in the method for manufacturing a circuit board disclosed in Patent Document 1, one wiring pattern is formed on a single prepreg sheet, and a plurality of prepreg sheets are stacked to manufacture a circuit board. Therefore, in the method for manufacturing a circuit board disclosed in Patent Document 1, it is necessary to stack prepreg sheets by the number of necessary wiring patterns, and there is a problem that the circuit board cannot be thinned.

  Further, the circuit board manufacturing method disclosed in Patent Document 1 has a problem that if the number of wiring patterns is increased, the same number of prepreg sheets are required, and the weight cannot be reduced. Furthermore, in the method for manufacturing a circuit board disclosed in Patent Document 1, if the thickness of the circuit board is restricted, the number of wiring patterns cannot be increased, and the mounting density of electronic components is reduced, resulting in miniaturization. There was a problem that could not.

  This invention is made | formed in view of the said situation, and it aims at providing the manufacturing method of the circuit board which can be reduced in size, weight, and thickness.

In order to achieve the above object, a method for manufacturing a circuit board according to a first aspect of the present invention is a method for manufacturing a circuit board by laminating a built-up layer made of a prepreg sheet on a core layer, wherein the built-in uncured build A first step of forming a first wiring pattern on one surface of the up layer, and the built-up layer is laminated on the core layer so that the first wiring pattern formed in the first step is on the core layer side. A second step of pressing the built-up layer to the core layer by applying an isotropic pressure while heating, and incorporating the first wiring pattern in the built-up layer, the second step comprising: In a state where the resin constituting the built-up layer existing in the vicinity of the one surface side of the core layer is inserted between the first wiring pattern and the core layer to form a resin layer, and the resin layer is formed. by heating and curing, before A first wiring pattern incorporated in the built-up layer.

  The circuit board manufacturing method according to a second aspect of the present invention includes, in the first aspect, a third step of forming a second wiring pattern on the other surface of the built-up layer before the second step.

  The circuit board manufacturing method according to a third aspect of the present invention includes, in the first aspect, a fourth step of forming a second wiring pattern on the other surface of the built-up layer after the second step.

  A circuit board manufacturing method according to a fourth aspect of the present invention includes the fifth step of forming a via conductor in the built-up layer in any one of the first to third aspects of the invention.

  The circuit board manufacturing method according to a fifth aspect of the present invention is the circuit board manufacturing method according to any one of the first to fourth aspects, wherein the second step includes the built-up so that the first wiring pattern is on the core layer side. A layer is laminated on both surfaces of the core layer, and is heated with an isotropic pressure while being heated, and the built-up layer is pressure-bonded to both surfaces of the core layer to incorporate the first wiring pattern in each built-up layer. .

  A circuit board manufacturing method according to a sixth aspect of the present invention is the method for manufacturing a circuit board according to any one of the first to fifth aspects of the present invention, wherein the first wiring pattern is connected to the core layer side on the core layer on which the built-up layer is laminated. The built-up layers are further laminated so that the plurality of built-up layers are pressure-bonded to the core layer by applying isotropic pressure while heating, and the first wiring pattern is built in each built-up layer. Including a sixth step.

  According to a seventh aspect of the present invention, there is provided the circuit board manufacturing method according to any one of the first to sixth aspects, wherein the first wiring pattern and / or the second wiring pattern are arranged via the built-up layer. A capacitor is formed with the counter electrode.

  According to an eighth aspect of the present invention, there is provided the circuit board manufacturing method according to any one of the first to sixth aspects, wherein the first wiring pattern and / or the second wiring pattern has a coil shape.

  The circuit board manufacturing method according to a ninth aspect of the present invention is the method according to any one of the first to eighth aspects, wherein the second step and the sixth step are performed in a vacuum state.

  The circuit board manufacturing method according to a tenth aspect of the present invention is the circuit board manufacturing method according to any one of the first to ninth aspects, wherein the core layer is made of a prepreg sheet, and the built-up layer is uncured in the second step. Are laminated.

In the first invention, the uncured built-up layer in which the first wiring pattern is formed on one surface in the first step is laminated on the core layer so that the first wiring pattern is on the core layer side in the second step, The resin constituting the built-up layer existing in the vicinity of one surface of the core layer is pressed between the first wiring pattern and the core layer by pressing with an isotropic pressure while heating to press-bond the built-up layer to the core layer. The first wiring pattern can be built in the built-up layer by forming a resin layer and forming a resin layer, followed by heat curing with the resin layer formed, and a thin insulating layer between the core layer and the first wiring pattern Can be manufactured. In addition, the built-up layer with the first wiring pattern formed on one side can be built in the built-up layer by simply applying pressure to the core layer by applying isotropic pressure while heating, reducing manufacturing costs. can do.

  In the second and third inventions, since the second wiring pattern is formed on the other surface of the built-up layer before or after the second step, the first wiring pattern and the first built-up layer Since the third or fourth step of forming the second wiring pattern is included, a circuit board that can be reduced in size, weight, and thickness can be manufactured.

  In the fourth invention, since the via conductor is formed in the built-up layer, a circuit board in which the first wiring pattern and the second wiring pattern are electrically joined can be manufactured, and the degree of freedom in circuit design is improved.

  In the fifth invention, the built-up layers are laminated on both surfaces of the core layer so that the first wiring pattern is on the core layer side, and the built-up layers are pressure-bonded to both surfaces of the core layer by applying pressure with isotropic pressure while heating. Thus, a circuit board having a thin insulating layer between the core layer and the first wiring pattern on both surfaces of the core layer can be manufactured. In addition, the first wiring pattern can be built in the built-up layer by simply pressing the built-up layer on which the first wiring pattern is formed with isotropic pressure while heating and crimping to the core layer, thereby reducing the manufacturing cost. Can do.

  In the sixth aspect of the present invention, the built-up layer is further laminated on the core layer on which the built-up layer is laminated so that the first wiring pattern is on the core layer side, and is heated with isotropic pressure while being heated. By crimping the built-up layer, the first wiring pattern can be built in each built-up layer, and a plurality of built-up layers having the first wiring pattern and the second wiring pattern are stacked on the core layer to further reduce the size. A circuit board that can be reduced in weight and thickness can be manufactured.

  In the seventh invention, the first wiring pattern and / or the second wiring pattern forms a capacitor with the counter electrode arranged via the built-up layer, so that the built-in capacitor is formed at a low manufacturing cost. be able to.

  In the eighth invention, since the first wiring pattern and / or the second wiring pattern has a coil shape, the built-in coil can be formed at a low manufacturing cost. By building up the built-up layer on which the coil-shaped first wiring pattern or second wiring pattern is formed, it is possible to increase the Q value of the coil without increasing the coil-shaped wiring pattern, and circuit design The degree of freedom increases.

  In the ninth invention, since the second step and the sixth step are performed in a vacuum state, when the built-up layer is laminated on the core layer, it is possible to suppress bubbles from entering between the built-up layer and the core layer. And a high-quality circuit board can be manufactured.

  In the tenth invention, the core layer is made of a prepreg sheet, and the built-up layer is laminated in an uncured state in the second step. Therefore, by setting the core layer and the built-up layer in a cured state in the same manufacturing process, The manufacturing process for setting only the layer to the cured state can be omitted, and the manufacturing cost can be reduced.

In the method for manufacturing a circuit board according to the present invention, an uncured built-up layer in which the first wiring pattern is formed on one side in the first step is used, and the first wiring pattern is on the core layer side in the second step. The first wiring pattern is formed by laminating the core layer, pressurizing with an isotropic pressure while heating, and press-bonding the built-up layer to the core layer, and forming the resin constituting the built-up layer existing in the vicinity of one surface side of the core layer. The first wiring pattern can be built in the built-up layer by forming a resin layer between the core layer and the core layer, and heating and curing in the state where the resin layer is formed . A circuit board having a thin insulating layer therebetween can be manufactured.

It is sectional drawing of the electronic component built-in module using the circuit board manufactured with the manufacturing method of the circuit board which concerns on Embodiment 1 of this invention. It is sectional drawing for demonstrating the process of preparing the core layer of the circuit board manufactured with the manufacturing method of the circuit board which concerns on Embodiment 1 of this invention. It is sectional drawing for demonstrating the process of preparing the built-up layer of the circuit board manufactured with the manufacturing method of the circuit board which concerns on Embodiment 1 of this invention. It is sectional drawing for demonstrating the process of manufacturing a circuit board with the manufacturing method of the circuit board which concerns on Embodiment 1 of this invention. It is sectional drawing for demonstrating the process of manufacturing a circuit board with the manufacturing method of the circuit board which concerns on Embodiment 2 of this invention. It is sectional drawing for demonstrating the process of manufacturing a circuit board with the manufacturing method of the circuit board which concerns on Embodiment 2 of this invention. It is an illustration figure which shows the wiring pattern of the built-up layer of the circuit board manufactured with the manufacturing method of the circuit board which concerns on Embodiment 3 of this invention.

  Hereinafter, a method for manufacturing a circuit board according to an embodiment of the present invention will be specifically described with reference to the drawings. The following embodiments do not limit the invention described in the claims, and all combinations of characteristic items described in the embodiments are essential to the solution. It goes without saying that it is not limited.

(Embodiment 1)
FIG. 1 is a cross-sectional view of an electronic component built-in module using a circuit board manufactured by the circuit board manufacturing method according to Embodiment 1 of the present invention. As shown in FIG. 1, an electronic component built-in module 100 includes a circuit board 1 manufactured by the method for manufacturing a circuit board according to Embodiment 1 of the present invention, and one surface of the circuit board 1 (the other surface of the built-up layer). A wiring pattern (second wiring pattern) 2 formed on the electronic circuit board 3, an electronic component 3 that is electrically bonded to the wiring pattern 2 with a conductive bonding material such as solder, and is mounted on the circuit board 1, and an electronic component 3 And a sealing resin 4 that covers one surface of the circuit board 1 on which is mounted.

  The circuit board 1 has a configuration in which a built-up layer 20 made of a prepreg sheet is laminated on a core layer 10 made of a prepreg sheet. Here, the prepreg sheet is a sheet obtained by impregnating a woven fabric such as glass cloth with a thermosetting resin (for example, epoxy resin). In addition, below, although the core layer 10 demonstrated the case where it consists of a prepreg sheet, it is not limited to the case where it consists of a prepreg sheet.

  The core layer 10 has a wiring pattern 11 formed on one surface on which the built-up layer 20 is laminated, and a wiring pattern 12 formed on one surface opposite to the one surface. The wiring pattern 11 and the wiring pattern 12 are electrically joined (connected) by via conductors 13 as necessary. The built-up layer 20 is formed with a wiring pattern 2 and a built-in wiring pattern (first wiring pattern) 21 on one surface (the other surface of the built-up layer 20) opposite to the one surface laminated on the core layer 10. It is. The wiring pattern 2, the wiring pattern 21, and the wiring pattern 11 are electrically joined by via conductors 22 and 23, respectively, as necessary.

  Next, a method for manufacturing the circuit board 1 according to Embodiment 1 of the present invention will be described. First, the process of preparing the core layer 10 of the circuit board 1 will be described. FIG. 2 is a cross-sectional view for explaining a step of preparing core layer 10 of circuit board 1 manufactured by the method of manufacturing circuit board 1 according to Embodiment 1 of the present invention. The core layer 10 made of a prepreg sheet is in an uncured state. Therefore, as shown to Fig.2 (a), as for the core layer 10, the protective sheet (For example, sheet | seats, such as a polyethylene terephthalate (PET)) 10a is affixed on both surfaces. A via hole is formed at a predetermined position by laser processing on the core layer 10 on which the protective sheet 10a is pasted, and a via conductor 13 is formed by filling the via hole with a conductive paste (FIG. 2 (b)). .

  The protective sheet 10a is peeled off from both surfaces of the core layer 10 on which the via conductors 13 are formed (FIG. 2C), and the metal foil 11a is attached to one surface of the core layer 10 and the metal foil 12a is attached to the other surface (FIG. 2D). )). Here, the metal foils 11a and 12a are, for example, copper foils and have a thickness of about 12 μm.

  The metal foils 11a and 12a are formed on the wiring patterns 11 and 12 having a predetermined pattern by performing a photolithography process and an etching process on the metal foils 11a and 12a attached to the core layer 10 (FIG. 2E )). Further, the core layer 10 on which the wiring patterns 11 and 12 are formed is heated to a cured state. The core layer 10 on which the wiring patterns 11 and 12 are formed is not limited to a cured state, and the built-up layer 20 may be laminated in an uncured state. When the built-up layer 20 is laminated on the uncured core layer 10, it is possible to omit a manufacturing process in which only the core layer 10 is heated to be in a cured state.

  Next, a process for preparing the built-up layer 20 of the circuit board 1 will be described. FIG. 3 is a cross-sectional view for explaining a step of preparing the built-up layer 20 of the circuit board 1 manufactured by the method of manufacturing the circuit board 1 according to Embodiment 1 of the present invention. The built-up layer 20 made of a prepreg sheet has a thickness of about 50 μm and is in an uncured state. Therefore, as shown in FIG. 3A, the built-up layer 20 has a protective sheet (for example, a sheet of polyethylene terephthalate (PET) or the like) 20a attached to both surfaces.

  The protective sheet 20a is peeled off from both surfaces of the built-up layer 20 (FIG. 3B), and the metal foil 2a is attached to one surface of the built-up layer 20 and the metal foil 21a is attached to the other surface (FIG. 3C). Here, the metal foils 2a and 21a are, for example, copper foils and have a thickness of about 12 μm.

  The metal foil 21a is formed on the wiring pattern 21 having a predetermined pattern by performing a photolithography process and an etching process on the metal foil 21a attached to the built-up layer 20 (FIG. 3D). That is, the wiring pattern (first wiring pattern) 21 is formed on one surface (one surface of the built-up layer 20) on the side of the uncured built-up layer 20 that is laminated on the core layer 10.

  Next, a process for manufacturing the circuit board 1 by laminating the built-up layer 20 on the core layer 10 will be described. FIG. 4 is a cross-sectional view for explaining a process of manufacturing the circuit board 1 by the method of manufacturing the circuit board 1 according to the first embodiment of the present invention. The built-up layer 20 (FIG. 4A) prepared in the step shown in FIG. 3 is laminated on the core layer 10 (FIG. 4B) prepared in the step shown in FIG. In a vacuum state, the built-up layer 20 laminated on the core layer 10 is pressed with an isotropic pressure while being heated, and is pressed onto the core layer 10. When the uncured built-up layer 20 is pressurized with an isotropic pressure while being heated, the resin of the built-up layer 20 in the vicinity of one surface laminated on the core layer 10 is between the wiring pattern 21 and the core layer 10. The resin film 24 of the built-up layer 20 is formed between the wiring pattern 21 and the core layer 10, and the wiring pattern 21 is built in the built-up layer 20 (FIG. 4C).

  In addition, the thickness of the resin film 24 of the built-up layer 20 can be made very thin (about 0.1 to 3 μm) as compared with the thickness of the resin insulating layer (about 30 to 100 μm) formed by a normal method. . In addition, when the built-up layer 20 laminated on the core layer 10 is pressurized with an isotropic pressure, the vacuum state is that when the built-up layer 20 is laminated on the core layer 10, the built-up layer 20 and the core layer This is to prevent bubbles from entering between the two. When the built-up layer 20 is laminated on the core layer 10, it is not necessary to limit to a vacuum state as long as bubbles can be prevented from entering between the built-up layer 20 and the core layer 10.

  Here, the uncured built-up layer 20 is pressed and pressure-bonded with the core layer 10 while being heated, and is further cured by heating. When the built-up layer 20 is laminated on the uncured core layer 10 without heating the core layer 10 in the step of preparing the core layer 10, the uncured core layer 10 is also heated with the built-up layer 20. While being pressurized, pressure bonding is performed, and a heat treatment is performed to obtain a cured state.

  Next, a via hole is formed in a predetermined position by laser processing on the built-up layer 20 in a cured state laminated on the core layer 10, and the via conductor 22 is filled with a conductive paste in the via hole. 23 is formed (FIG. 4D). The bottom of the via conductor 22 is the wiring pattern 21, and the bottom of the via conductor 23 is the wiring pattern 11.

  Next, the metal foil 2a attached to the built-up layer 20 is subjected to a photolithography process and an etching process, thereby forming the metal foil 2a in the wiring pattern 2 having a predetermined pattern (FIG. 4E). ). That is, the wiring pattern (second wiring pattern) 2 is formed on one surface of the built-up layer 20 opposite to the surface that is laminated on the core layer 10. However, the formation of the wiring pattern 2 is not limited to the case where it is performed after the built-up layer 20 is laminated on the core layer 10 and pressure-bonded, and the step of preparing the built-up layer 20 (FIG. 3D) In this case, the metal foil 2a may be formed on the wiring pattern 2 having a predetermined pattern by performing a photolithography process and an etching process on the metal foil 2a attached to the built-up layer 20.

  As described above, in the method for manufacturing the circuit board 1 according to the first embodiment of the present invention, the wiring pattern 21 is formed on one surface of the uncured built-up layer 20 on the side laminated with the core layer 10, Since the built-up layer 20 is laminated on the core layer 10 so that the wiring pattern 21 is on the core layer 10 side, the built-up layer 20 is pressure-bonded to the core layer 10 by applying pressure with isotropic pressure while heating. The resin film 24 of the built-up layer 20 can be formed between the core layer 10 and the core layer 10 so that the wiring pattern 21 can be built in the built-up layer 20. A circuit board that can be reduced in size, weight, and thickness by forming the wiring pattern 21 and the wiring pattern 2 in the single built-up layer 20 by incorporating the wiring pattern 21 in the built-up layer 20. 1 can be manufactured.

  4 illustrates a method for manufacturing the circuit board 1 in which the built-up layer 20 is laminated only on the surface of the core layer 10 on which the wiring pattern 11 is formed, the circuit board according to the first embodiment of the present invention. The manufacturing method 1 is not limited to this, and the built-up layer 20 may be laminated on the surface of the core layer 10 on which the wiring pattern 12 is formed. The wiring patterns 2 and 12 may be electrically bonded to the electronic component 3 with a conductive bonding material such as solder and covered with the sealing resin 4.

(Embodiment 2)
The circuit board 1 manufactured by the method for manufacturing the circuit board 1 according to Embodiment 2 of the present invention has a configuration in which a plurality of built-up layers 20 are stacked on one surface of the core layer 10. Since the step of preparing the core layer 10 of the circuit board 1 and the step of preparing the built-up layer 20 are the same as those in the first embodiment, the description thereof is omitted.

  5 and 6 are cross-sectional views for explaining a process of manufacturing the circuit board 1 by the method of manufacturing the circuit board 1 according to the second embodiment of the present invention. The built-up layer 20 (FIG. 5 (a)) prepared in the step shown in FIG. 3 is laminated on the core layer 10 (FIG. 5 (b)) prepared in the step shown in FIG. The prepared built-up layer 20 forms the metal foil 2a on the wiring pattern 2 having a predetermined pattern by performing a photolithography process and an etching process on the metal foil 2a attached to the built-up layer 20. It is.

  Next, in a vacuum state, the built-up layer 20 laminated on the core layer 10 is pressure-bonded to the core layer 10 by applying an isotropic pressure while heating. When the uncured built-up layer 20 is pressurized with an isotropic pressure while being heated, the resin of the built-up layer 20 in the vicinity of one surface laminated on the core layer 10 is between the wiring pattern 21 and the core layer 10. The resin film 24 of the built-up layer 20 is formed between the wiring pattern 21 and the core layer 10, and the wiring pattern 21 is built in the built-up layer 20 (FIG. 5C).

  Next, a via hole is formed in a predetermined position by laser processing on the built-up layer 20 in a cured state laminated on the core layer 10, and the via conductor 22 is filled with a conductive paste in the via hole. 23 is formed (FIG. 5D). The bottom of the via conductor 22 is the wiring pattern 21, and the bottom of the via conductor 23 is the wiring pattern 11.

  Next, the built-up layer 30 (FIG. 6E) prepared in the same process as the process shown in FIG. 3 is laminated on the core layer 10 (FIG. 6F) on which the built-up layer 20 is laminated. The built-up layer 30 has the same configuration as the built-up layer 20, and the wiring pattern 31 is provided on one side laminated on the built-up layer 20, and the wiring is provided on one side opposite to the one side laminated on the built-up layer 20. Each pattern 32 is formed. In a vacuum state, the built-up layer 30 is further laminated on the core layer 10 on which the built-up layer 20 is laminated, and the built-up layer 30 is laminated on the core layer 10 on which the built-up layer 20 is laminated by applying pressure with isotropic pressure while heating. Crimp the. When the uncured built-up layer 30 is pressurized with an isotropic pressure while being heated, the resin of the built-up layer 30 in the vicinity of one surface to be laminated on the built-up layer 20 becomes the wiring pattern 31 and the built-up layer 20. The resin film 33 of the built-up layer 30 is formed between the wiring pattern 31 and the built-up layer 20, and the wiring pattern 31 is built in the built-up layer 30 (FIG. 6G).

  Next, a via hole is formed by laser processing at a predetermined position on the hardened built-up layer 30 laminated on the core layer 10 on which the built-up layer 20 is laminated, and a conductive paste is applied to the via hole. The via conductors 34 and 35 are formed by filling (FIG. 6H). The wiring pattern 31 and the wiring pattern 32 are electrically joined by a via conductor 34 as necessary. Further, the wiring pattern 31 and the wiring pattern 2 are electrically joined by a via conductor 35 as necessary.

  As described above, in the method for manufacturing the circuit board 1 according to the second embodiment of the present invention, since the plurality of built-up layers 20 and 30 are stacked on the core layer 10, two wiring patterns 21, 2, 31, A plurality of built-up layers 20 and 30 formed with 32 can be laminated on the core layer 10, and a circuit board that can be further reduced in size, weight, and thickness can be manufactured.

  5 and 6 illustrate a method for manufacturing the circuit board 1 in which a plurality of built-up layers 20 and 30 are stacked only on the surface of the core layer 10 on which the wiring pattern 11 is formed. The manufacturing method of the circuit board 1 according to the second embodiment is not limited to this, and a plurality of built-up layers 20 and 30 may be laminated on the surface of the core layer 10 on which the wiring pattern 12 is formed. The wiring patterns 32 and 12 may be electrically bonded to the electronic component 3 with a conductive bonding material such as solder and covered with the sealing resin 4.

(Embodiment 3)
The wiring pattern 21 formed on the built-up layer 20 of the circuit board 1 manufactured by the method for manufacturing the circuit board 1 according to the third embodiment of the present invention includes the counter electrode disposed via the built-up layer 20 and the counter electrode. A capacitor is formed between the two. For example, as shown in FIG. 4 (e), the wiring pattern 21 b forms a capacitor with the wiring pattern 11 (counter electrode) disposed via the resin film 24 of the built-up layer 20. That is, by forming the wiring pattern 21b so as to face the wiring pattern 11 through the resin film 24 of the built-up layer 20, the built-in capacitor can be formed at a low manufacturing cost.

  Further, since the resin film 24 of the built-up layer 20 is formed by the uncured resin of the built-up layer 20 entering between the wiring pattern 21 and the core layer 10, the thickness is formed by a normal method. The thickness of the insulating layer of the resin can be made very thin. Therefore, a high-capacitance capacitor is formed between the wiring pattern 21b formed in the built-up layer 20 and the wiring pattern 11 (counter electrode) disposed via the resin film 24 of the built-up layer 20. Can do.

  Further, the wiring patterns 21 and 31 formed on the built-up layers 20 and 30 of the circuit board 1 manufactured by the method of manufacturing the circuit board 1 according to Embodiment 3 of the present invention may be coil-shaped. FIG. 7 is an exemplary view showing a wiring pattern 21 of the built-up layer 20 of the circuit board 1 manufactured by the method of manufacturing the circuit board 1 according to the second embodiment of the present invention. As shown in FIG. 7, the built-in coil can be formed at a low manufacturing cost simply by forming the coil-shaped wiring pattern 21 on the built-up layer 20. Further, as shown in FIG. 6 (h), the wiring patterns 21, 2, 31, and 32 formed on the built-up layers 20 and 30 of the circuit board 1 are formed in a coil shape, and the via conductors 22, 23, 34, By connecting the respective wiring patterns 21, 2, 31, 32 at 35, it is possible to make the coil multi-layered and to increase the Q value of the coil without increasing the coil-shaped wiring pattern. The degree of freedom in circuit design is improved.

  The wiring patterns 21 and 31 are not limited to the above-described patterns, and may be general circuit patterns.

DESCRIPTION OF SYMBOLS 1 Circuit board 2, 11, 12, 21, 31, 32 Wiring pattern 2a, 11a, 12a, 21a Metal foil 3 Electronic component 4 Sealing resin 10 Core layer 20, 30 Built-up layer 13, 22, 23, 34, 35 Via conductor 10a, 20a Protection sheet 100 Electronic component built-in module

Claims (10)

A method of manufacturing a circuit board by laminating a built-up layer made of a prepreg sheet on a core layer,
A first step of forming a first wiring pattern on one surface of the uncured built-up layer, and the built-up layer so that the first wiring pattern formed in the first step is on the core layer side A second step of laminating the core layer, pressurizing at an isotropic pressure while heating, and crimping the built-up layer to the core layer to incorporate the first wiring pattern in the built-up layer,
Second step, the resin constituting the built-up layer present on one side near the core layer, to form a resin layer by entering between the first wiring pattern and the core layer, the A method of manufacturing a circuit board , wherein the first wiring pattern is built in the built-up layer by heat-curing in a state where a resin layer is formed .   The method for manufacturing a circuit board according to claim 1, further comprising a third step of forming a second wiring pattern on the other surface of the built-up layer before the second step.   The method for manufacturing a circuit board according to claim 1, further comprising a fourth step of forming a second wiring pattern on the other surface of the built-up layer after the second step.   4. The circuit board manufacturing method according to claim 1, further comprising a fifth step of forming a via conductor in the built-up layer. 5.   In the second step, the built-up layer is laminated on both surfaces of the core layer so that the first wiring pattern is on the core layer side, and is heated with isotropic pressure while being heated. 5. The method of manufacturing a circuit board according to claim 1, wherein the built-up layer is pressure-bonded to incorporate the first wiring pattern in each of the built-up layers. 6.   The built-up layer is further laminated on the core layer on which the built-up layer is laminated so that the first wiring pattern is on the core layer side, and a plurality of pressure is applied to the core layer by applying an isotropic pressure while heating. 6. The circuit board according to claim 1, further comprising a sixth step of crimping the built-up layer and incorporating the first wiring pattern in each built-up layer. 7. Production method.   7. The capacitor according to claim 1, wherein the first wiring pattern and / or the second wiring pattern forms a capacitor with the counter electrode arranged via the built-up layer. The manufacturing method of the circuit board as described in a term.   The method for manufacturing a circuit board according to claim 1, wherein the first wiring pattern and / or the second wiring pattern is in a coil shape.   The method for manufacturing a circuit board according to claim 1, wherein the second step and the sixth step are performed in a vacuum state.   The method for manufacturing a circuit board according to claim 1, wherein the core layer is made of a prepreg sheet, and the built-up layer is laminated in an uncured state in the second step.

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