JP5264651B2 - Method for manufacturing printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a printed wiring board improved in reliability. <P>SOLUTION: The method of manufacturing the printed wiring board 10 includes the processes of: forming a core including carbon fiber-reinforced plastic having a first through hole; forming a first film on a lower surface of the core to cover the first through hole and filling the first through hole with a first insulating member; removing the first film; forming a second through hole in the core; forming a second film on an upper surface of the core to cover the second through hole and filling the second through hole with a second insulating member; removing the second film; and forming a circuit at least on one of the first and second insulating members. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method for manufacturing a printed wiring board, and more particularly to a method for manufacturing a printed wiring board having a core containing carbon fiber reinforced plastic.

  In recent years, printed circuit boards have come to be desired to have a substrate with good heat dissipation as the density of electronic components increases. A metal core substrate is known as a printed wiring board excellent in heat dissipation and has already been put into practical use. By using a metal having a high thermal conductivity as the core material, the metal core substrate can disperse heat from the heat-generating component over the entire printed wiring board and suppress the temperature rise of the heat-generating component. Among these, aluminum having a small specific gravity is generally used as the core material.

  However, the coefficient of thermal expansion of aluminum is as high as about 24 ppm / K, and the coefficient of thermal expansion of ceramic parts is as low as about 7 ppm / K. For this reason, when a heat cycle test is performed, a crack occurs in a solder joint due to a difference in thermal expansion coefficient between aluminum and a ceramic component, and there is a problem that mounting reliability cannot be obtained.

Carbon fiber reinforced plastics (hereinafter also referred to as CFRP) are known as a core material that can solve the above problems (see, for example, Patent Document 1). CFRP is a composite material composed of carbon fiber and resin. The thermal expansion coefficient of carbon fibers is as low as ± 2 ppm / K, and some carbon fibers have a thermal conductivity of 500 Wm ⁻¹ K ⁻¹ or more. The specific gravity of the carbon fiber is as low as about 2 g / cm ³ . If a core substrate can be produced using this CFRP, a substrate having high thermal conductivity and better mounting reliability than aluminum can be obtained.

  Since all of the above-described core materials are conductive, it is necessary to insulate the through through hole connecting the wirings above and below the core material and the core material with a resin filling the through hole. Normally, filling of the through holes is achieved by stacking a semi-cured prepreg obtained by impregnating a glass cloth with an epoxy resin on top of and below the core material after forming the through holes. That is, the prepreg is melted by the heat at the time of lamination, and the resin that has flowed by pressurization is filled into the through holes.

Japanese Patent Laid-Open No. 11-40902

  However, when a conventional prepreg is used for filling the through hole, the thermal expansion coefficient of the resin formed on the upper and lower surfaces of the CFRP core and filled in the through hole is 60 ppm / K, whereas the thermal expansion of the CFRP core is The rate is about 0 ppm / K. For this reason, the subject that a board | substrate end surface peeled by shrinkage | contraction of resin occurred. When the substrate end face is peeled off, the reliability of the printed wiring board is lowered.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a printed wiring board manufacturing method with improved reliability.

  The manufacturing method of the printed wiring board of this invention is equipped with the following processes. A core including a carbon fiber reinforced plastic having a first through hole is formed. A first film is formed on the lower surface of the core so as to cover the first through hole, and the first insulating member is filled into the first through hole. Remove the first film. A second through hole is formed in the core. A second film is formed on the upper surface of the core so as to cover the second through hole, and the second insulating member is filled in the second through hole. Remove the second film. A circuit is formed on at least one of the first and second insulating members.

  According to the method for manufacturing a printed wiring board of the present invention, by forming the first and second through holes so as to surround the outer periphery of the region to be the printed wiring board by the first and second through holes, The first and second insulating members can be arranged so as to surround the outer periphery. When the outer shape is processed along the outer periphery of the region to be the printed wiring board, the first and second insulating members can be formed on the end face of the printed wiring board. Thereby, the printed wiring board which coat | covered the end surface of the core with the 1st and 2nd insulating member can be manufactured. For this reason, it can suppress that a core peels. Therefore, a printed wiring board with improved reliability can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS The structure of the printed wiring board in embodiment of this invention is shown schematically, (A) is a top view, (B) is sectional drawing along the IB-IB line in (A). It is the schematic which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process, (A) is a top view, (B) is sectional drawing along the IIB-IIB line | wire in (A). . It is the schematic which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process, (A) is a top view, (B) is sectional drawing along the IIIB-IIIB line in (A). . It is the schematic diagram sectional drawing which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process. It is the schematic which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process, (A) is a top view, (B) is sectional drawing along the VB-VB line | wire in (A). . It is the schematic diagram sectional drawing which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process. It is the schematic which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process, (A) is a top view, (B) is sectional drawing along the VIIB-VIIB line | wire in (A). . It is the schematic diagram sectional drawing which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process. It is the schematic which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process, (A) is a top view, (B) is sectional drawing along the IXB-IXB line | wire in (A). . It is the schematic diagram sectional drawing which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process. It is the schematic diagram sectional drawing which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process. It is the schematic diagram sectional drawing which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process. It is the schematic diagram sectional drawing which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process. It is the schematic diagram sectional drawing which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process. It is the schematic which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process, (A) is a top view, (B) is sectional drawing along the XVB-XVB line | wire in (A). . It is the schematic which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process, (A) is a top view, (B) is sectional drawing along the XVIB-XVIB line in (A). .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

  1A and 1B schematically show a configuration of a printed wiring board according to an embodiment of the present invention, where FIG. 1A is a plan view and FIG. 1B is a cross-sectional view. As shown in FIGS. 1A and 1B, the printed wiring board 10 includes a signal circuit layer 6a, a CFRP core 1 as a core including a CFRP layer, a first hole filling resin 4a, and a second hole filling. The resin 4b and the insulating layer 5 are mainly included.

  The signal circuit layer 6a is formed on the surface of the insulating layer 5 and has wiring. The wiring is made of copper, for example.

  The CFRP core 1 is provided between the signal circuit layers 6a. The CFRP core 1 may be a composite material composed of carbon fibers and a resin, and the carbon fiber content, structure (unidirectional material, cloth material), etc. in the composite material are not particularly limited. The CFRP core 1 has a first primary through hole 2a and a second primary through hole 2b.

  The pair of upper and lower signal circuit layers 6a are electrically connected to each other through a through-hole 7 plated with copper on the secondary through-hole 7a. Since the CFRP core 1 is conductive, it is necessary to insulate the CFRP core 1 from the through-through hole 7. A secondary through hole 7a having a smaller diameter is formed on the same axis as the first primary through hole 2a, and is electrically insulated by the first filling resin 4a.

  The first and second hole filling resins 4 a and 4 b are formed between the insulating layer 5 and the CFRP core 1. The first and second hole-filling resins 4 a and 4 b are located on the end surface 10 a of the printed wiring board 10 and cover the end surface of the CFRP core 1.

  The first and second hole-filling resins 4a and 4b are preferably an epoxy resin containing silica, and more preferably an insulating member having a coefficient of thermal expansion of about 30 ppm / K composed of silica and a resin. The reason why it is preferable to use silica for the first and second hole-filling resins 4a and 4b is to improve the drillability of the secondary through hole 7a and to relieve stress between the CFRP core 1 and the through through hole 7.

  The insulating layer 5 is preferably made of glass cloth and resin. The resin constituting the insulating layer 5 and the first and second hole-filling resins 4a and 4b is not particularly limited, and for example, epoxy, bismaleimide, cyanate ester, polyimide, or the like can be used.

  The first and second hole-filling resins 4a and 4b and the insulating layer 5 may be made of different materials or the same material. The first and second hole-filling resins 4a and 4b are preferably made of the same material from the viewpoint that stress such as warpage can be relieved by using a symmetrical structure.

  Then, the manufacturing method of the printed wiring board of this Embodiment is demonstrated. 2-16 is the schematic which shows the manufacturing method of the printed wiring board in embodiment of this invention in order of a process. Specifically, for example, the following steps are performed.

  First, as shown in FIGS. 2A and 2B, a CFRP core 1 is prepared. Next, as shown in FIGS. 3A and 3B, the first primary through hole 2 a is formed in the CFRP core 1. At this time, as shown in FIG. 3 (B), a part of the outer shape of the product (the outer periphery of the region to be the printed wiring board 10 shown in FIGS. 1 (A) and (B)) It is preferable to form with 2a long hole.

  The first primary through hole 2a is formed using, for example, a drill. After forming the first primary through hole 2a, ultrasonic cleaning may be performed in order to remove carbon powder and the like attached to the inner wall of the first primary through hole 2a.

  Next, as shown in FIG. 4, the 1st backing film 3a is affixed on the lower surface of the CFRP core 1 so that the 1st primary through-hole 2a may be covered.

  Next, as shown in FIGS. 5A and 5B, the first primary through hole 2a is printed and filled with the paste-like first hole filling resin 4a and cured. Since the first backing film 3a is provided, it is possible to prevent the filled resin from dropping off. In particular, since the first backing film 3a serves as a bottom, even if the diameter of the first primary through hole 2a is large or a long hole (slit), the first filling resin 4a It can suppress falling off from the 1st primary through hole 2a. Thereby, the 1st primary penetration hole 2a can be filled with the 1st hole filling resin 4a.

  Here, the paste-like first hole-filling resin 4a preferably contains silica and has a coefficient of thermal expansion of about 30 ppm / K after curing. The paste-like first hole-filling resin 4a is preferably printed and filled with a vacuum coater.

  Next, as shown in FIG. 6, the first backing film 3a is removed. For example, polyethylene terephthalate with an adhesive can be used for the first backing film 3a.

  Next, as shown in FIGS. 7A and 7B, the second primary through hole 2 b is formed in the CFRP core 1. At this time, as shown in FIG. 7A, the second primary penetration is made so that there is no portion where the first primary through hole 2a in the outer peripheral portion of the product is not formed and the CFRP core 1 remains. Hole 2b is formed. That is, the second primary so as to communicate with the first primary through hole 2a and to surround the outer periphery of the region to be the printed wiring board by the first and second primary through holes 2a and 2b. The through hole 2b is formed.

  The second primary through hole 2b is formed using, for example, a drill. After forming the second primary through hole 2b, ultrasonic cleaning may be performed in order to remove carbon powder and the like attached to the inner wall of the second primary through hole 2b.

  Next, as shown in FIG. 8, the 2nd backing film 3b is affixed on the upper surface of the CFRP core 1 so that the 2nd primary through-hole 2b may be covered. The second backing film 3b may be the same material as the first backing film 3a or a different material.

  Next, as shown in FIGS. 9A and 9B, the paste-like second hole-filling resin 4b is printed and filled and cured. The second hole filling resin 4b is preferably the same material as the first hole filling resin 4a. Since the second backing film 3b serves as a bottom, even if the diameter of the second primary through hole 2b is large or a long hole, the first filling resin 4b is the second primary resin. It can suppress falling off from the through hole 2b. Thus, the second primary through hole 2b can be filled with the second hole filling resin 4b. When this process is carried out, the first and second hole-filling resins 4a and 4b are arranged in the region to be the end face of the printed wiring board.

  Next, as shown in FIG. 10, the second backing film 3b is removed to form a laminate.

  Next, as shown in FIG. 11, the insulating layer 5 and the copper foil 6 made of prepreg are disposed above and below the laminate of FIG. The copper foil 6 constitutes the signal circuit layer 6a.

  Next, as shown in FIG. 12, copper foil is disposed and laminated on the upper and lower sides of the laminated body of FIG. In this step, the insulating layer 5 is laminated so as to contact the first and second hole-filling resins 4a and 4b under a predetermined condition using, for example, a vacuum press in the state of FIG.

  Next, as shown in FIG. 13, a secondary through hole 7a having a diameter smaller than that of the first primary through hole 2a is formed on the same axis as the first primary through hole 2a. The axes of the first primary through hole 2a and the secondary through hole 7a may be different.

  Next, as shown in FIG. 14, plating such as copper plating is performed to form a conductive layer in the secondary through hole 7a. When the conductive layer is formed, the through-hole 7 is formed as shown in FIG.

  Next, as shown in FIGS. 15A and 15B, the copper foil 6 is patterned to form a signal circuit layer 6a. Thereafter, solder resist processing, solder leveler processing, and the like are performed.

  Next, as shown in FIGS. 16A and 16B, the first hole filling filled in the first primary through hole 2a forming the outer peripheral part of the product (the outer periphery of the printed wiring board 10 in FIG. 1). The outer shape is processed with the resin 4a and the second hole-filling resin 4b filled in the second primary through hole 2b, and the product (the printed wiring board 10 in FIG. 1) is taken out from the workpiece. In this step, for example, the product (printed wiring board 10) can be taken out by forming the through hole 8 in the outer periphery of the product.

  The printed wiring board 10 shown to FIG. 1 (A) and (B) can be manufactured according to the above process. On the end surface 10a of the printed wiring board, the first and second hole-filling resins 4a and 4b are located.

  Then, the effect of the manufacturing method of the printed wiring board 10 in this Embodiment is demonstrated compared with the manufacturing method of the printed wiring board by the conventional lamination system.

  In the conventional method of manufacturing a printed wiring board by a lamination method, glass epoxy prepregs are laminated on the upper and lower surfaces of a CFRP core, and the molten epoxy resin is filled in the primary through holes. Since the epoxy resin is filled in the primary through hole and the upper and lower surfaces of the CFRP core, a difference in thermal expansion coefficient from the CFRP core occurs. For this reason, when a thermal cycle test is performed, cracks occur in the resin and the CFRP core, or the end face of the CFRP core peels off. As a result, the reliability of the printed wiring board has been reduced.

  On the other hand, the method of manufacturing the printed wiring board 10 in the present embodiment includes a step of forming the CFRP core 1 having the first through hole (first primary through hole 2a), and the first through hole (first The first film (first backing film 3a) is formed on the lower surface of the CFRP core 1 so as to cover the primary through hole 2a), and the first through hole (first primary through hole 2a) is formed. A step of filling the first insulating member (first hole filling resin 4a), a step of removing the first film (first backing film 3a), and a second through hole (second hole) in the CFRP core 1. And forming a second film (second backing film 3b) on the upper surface of the CFRP core 1 so as to cover the second through hole (second primary through hole 2b). ) And the second insulating member (second hole embedded) in the second through hole (second primary through hole 2b). The step of filling the resin 4b), the step of removing the second film (second backing film 3b), and the first and second insulating members (first and second hole-filling resins 4a and 4b). Forming a circuit (signal circuit layer 6a) on at least one side.

  Note that an insulating layer may be further disposed between the circuit and at least one of the first and second insulating members, or may be provided in contact with the first and second insulating members.

  According to the method for manufacturing printed wiring board 10 in the present embodiment, the first and second primary through holes 2a and 2b surround the outer periphery of the region to be printed wiring board 10 with the first and second primary through holes 2a and 2b. By forming the primary through holes 2a and 2b, the first and second hole-filling resins 4a and 4b can be arranged so as to surround the outer periphery thereof. When the outer shape is processed along the outer periphery of the region to be the printed wiring board 10, the first and second hole-filling resins 4 a and 4 b can be exposed on the end face 10 a of the printed wiring board 10. Thereby, the printed wiring board 10 which coat | covered the end surface of the CFRP core 1 with the 1st and 2nd hole filling resin 4a, 4b can be manufactured. For this reason, even if it performs a heat cycle test, it can suppress that the CFRP core 1 located in an end surface peels. That is, even when stress due to a difference in thermal expansion coefficient is applied, the first and second hole-filling resins 4a and 4b located on the end surface 10a reduce the adhesion between the carbon fiber of the CFRP core 1 and the resin. Can be suppressed. Therefore, the printed wiring board 10 with improved reliability can be manufactured.

  In particular, in the present embodiment, the first and second hole-filling resins 4a and 4b are filled with the first and second backing films 3a and 3b formed on the lower or upper surface of the CFRP core 1 as the bottom. it can. Thus, the first and second hole-filling resins 4a and 4b can be filled in advance before applying the lamination pressure. For this reason, it is not necessary to have a thickness in consideration of conditions such as melting of the first and second hole-filling resins 4a and 4b. That is, the first and second hole-filling resins 4a and 4b can be formed while reducing the thickness and suppressing the generation of voids. For this reason, the printed wiring board 10 in which the first and second hole-filling resins 4a and 4b are arranged on the end surface 10a can be easily manufactured.

  Preferably, in the method of manufacturing the printed wiring board 10, in the step of forming the second primary through hole 2 b, the first and second primary through holes are communicated with the first primary through hole 2 a. The second primary through hole 2b is formed so as to surround the outer periphery of the region to be the printed wiring board 10 by the holes 2a and 2b.

  As a result, the first and second primary through holes 2a and 2b are filled with the first and second hole-filling resins 4a and 4b. When processed, the printed wiring board 10 having the first and second hole-filling resins 4a and 4b as end faces can be manufactured.

  In the present embodiment, the first and second primary through holes 2a and 2b form the outer periphery of the region to be the printed wiring board 10, but the first and second primary through holes 2a 2b and the third through hole may form the outer periphery of the region to be the printed wiring board 10.

  In the printed wiring board manufacturing method, the first and second insulating members (first and second hole-filling resins 4a and 4b) are preferably epoxy resins containing silica.

  The epoxy resin containing silica is a material having a low coefficient of thermal expansion of about 30 ppm / K. For this reason, the difference in coefficient of thermal expansion between the CFRP core 1 and the first and second hole-filling resins 4a and 4b can be reduced. Thereby, even if it performs a heat cycle test, it can suppress that the 1st and 2nd hole filling resin 4a, 4b and the CFRP core 1 generate | occur | produce a crack. Therefore, the printed wiring board 10 with further improved reliability can be manufactured.

  In the present embodiment, the method for manufacturing a single-layer printed wiring board has been described. However, the method for manufacturing a printed wiring board according to the present invention can also be applied to a multilayer printed wiring board.

Hereinafter, examples will be shown and described in more detail.
Example 1
In Example 1, basically, the method for manufacturing the printed wiring board 10 in the above-described embodiment was followed.

  Specifically, first, a CFRP core 1 (thickness 0.5 mm, size 340 mm × 250 mm) made of carbon fiber (cross material) having a thermal conductivity of 500 W / (m · K) was prepared (FIG. 2A). (See (B)).

  Next, the CFRP core 1 was drilled to provide a first primary through hole 2a having a diameter of 1.5 mm (see FIGS. 3A and 3B). At this time, as shown in FIG. 3A, a part of the outer shape of the product was formed as a long hole of the first primary through hole 2a.

  Next, the 1st backing film 3a was affixed on the lower surface of the CFRP core 1 (refer FIG. 4). For the first backing film 3a, polyethylene terephthalate with an adhesive was used.

  Next, silica-containing epoxy resin (manufactured by Taiyo Ink, THP-100DX1, 33 ppm / K) was printed and filled with a vacuum coater as the first hole-filling resin 4a, and kept at 120 ° C./1 h in an oven and cured (FIG. 5 ( A) (see B)). Next, the first backing film 3a was removed (see FIG. 6).

  Next, drilling was performed so that there was no portion where the CFRP core 1 remained where the first primary through hole 2a in the outer peripheral portion of the product was not formed, and the second primary through hole 2b was formed. (See FIGS. 7A and 7B).

  Next, the 2nd backing film 3b was affixed on the upper surface of the CFRP core 1 (refer FIG. 8). For the second backing film 3b, polyethylene terephthalate with an adhesive was used.

  Next, as a second hole filling resin 4b, a silica-containing epoxy resin (manufactured by Taiyo Ink, THP-100DX1, 33 ppm / K) was printed and filled with a vacuum coater, and kept at 120 ° C./1 h in an oven and cured (FIG. 9 ( A) (see B)). Next, the second backing film 3b was removed (see FIG. 10).

Next, as the insulating layer 5, 18 μm of copper foil 6 is disposed through a glass epoxy prepreg (Hitachi Chemical Industry Co., Ltd .: GEA-67N, thermal expansion coefficient 13 ppm / K to 16 ppm / K) having a thickness of 60 μm. (See FIG. 11). In this state, pressure was heated using a vacuum press under the conditions of a heating rate of 5 ° C./min, a holding time of 190 ° C./1 h, and a lamination pressure of 20 kg / cm ² (see FIG. 12).

  Next, a secondary through hole 7a having a diameter of 0.9 mm was provided coaxially with the first primary through hole 2a having a diameter of 1.5 mm (see FIG. 13). Next, copper plating was performed to form a copper layer as a conductive layer in the secondary through hole 7a (see FIG. 14). Next, patterning was performed (see FIGS. 15A and 15B).

  Next, after solder coating by solder resist coating and gas leveler processing, portions where the first and second filling resins 4a and 4b of the first primary through holes 2a and 2b forming the outer peripheral portion of the product exist The outer shape was processed, and the product was removed from the workpiece (see FIGS. 16A and 16B). Thus, the printed wiring board 10 as shown to FIG. 1 (A) and (B) was obtained.

  The thickness of the obtained CFRP core substrate was about 0.9 mm. When a heat cycle test (−65 ° C./15 minutes to 125 ° C./15 minutes, 100 cycles) was carried out, there was no short circuit or disconnection, and then a cross-sectional observation showed no cracks or peeling.

(Comparative Example 1)
The CFRP core 1 shown in FIGS. 2A and 2B was prepared in the same manner as in Example 1. Next, the CFRP core 1 was drilled to provide a first primary through hole 2a having a diameter of 1.5 mm. Three glass epoxy prepregs (GEA-67N) having a thickness of 100 μm and a copper foil having a thickness of 18 μm are arranged on the upper and lower sides of the obtained CFRP core 1, respectively, and the heating rate is 5 ° C. using a vacuum press. / Min, holding time of 190 ° C./1 h, and lamination pressure of 30 kg / cm ² .

  Thereafter, in the same manner as in Example 1, secondary through drilling, copper plating, patterning, and the like were performed to obtain a printed wiring board. Here, the first primary through holes 2a and 2b were not formed on the outer peripheral portion of the product. Therefore, the CFRP core was exposed on the end face of the obtained printed wiring board.

  The thickness of the obtained CFRP core substrate was about 1.2 mm. When a heat cycle test (−65 ° C./15 minutes to 125 ° C./15 minutes, 100 cycles) was performed, cracks occurred in the resin around the through-holes, and peeling was observed on the CFRP core 1 on the end face of the substrate. .

  Although the embodiments and examples of the present invention have been described above, it is also planned from the beginning to appropriately combine the features of the embodiments and examples. In addition, it should be considered that the embodiment disclosed this time is illustrative and not restrictive in all respects. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be particularly advantageously applied to a method of manufacturing a printed wiring board having a core containing CFRP and the printed wiring board.

  DESCRIPTION OF SYMBOLS 1 CFRP core, 2a 1st primary through hole, 2b 2nd primary through hole, 3a 1st backing film, 3b 2nd backing film, 4a 1st hole filling resin, 4b 2nd hole filling Resin, 5 Insulating layer, 6 Copper foil, 6a Signal circuit layer, 7 Through through hole, 7a Secondary through hole, 8 Through hole, 10 Printed wiring board, 10a End face.

Claims (2)

A method of manufacturing a printed wiring board,
Forming a core comprising a carbon fiber reinforced plastic having a first through hole;
Forming a first film on the lower surface of the core so as to cover the first through hole, and filling the first through hole with a first insulating member;
Removing the first film;
Forming a second through hole in the core;
Forming a second film on the upper surface of the core so as to cover the second through-hole, and filling the second through-hole with a second insulating member;
Removing the second film;
Forming a circuit on at least one of the first and second insulating members.   In the step of forming the second through hole, so as to communicate with the first through hole and to surround the outer periphery of the region to be the printed wiring board with the first and second through holes, The method for manufacturing a printed wiring board according to claim 1, wherein the second through hole is formed.

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