JPH11340599A - Double-sided printed wiring board and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a double-sided printed wiring board by simplified manufacturing steps. SOLUTION: This method for manufacturing a double-sided printed wiring board comprises the steps of etching a double-sided copper clad laminate formed by using a pair of copper foils coated on one end face with an adhesive 12 to form conductor patterns 16a, 16b of a predetermined shape, then bringing a metal plate having an ultrafine bar-like protrusion provided at a site for connecting a front surface to the rear surface into contact with the pattern 16a, applying a predetermined pressure to the metal plate at a predetermined temperature in this state, and pressing and bringing the pattern 16a to and into pressure contact with the pattern 16b side by the protrusion provided at the plate, thereby electrically connecting front surface to the rear surface of the board 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided printed wiring board manufactured using a thin plate-shaped double-sided copper-clad laminate and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become smaller and more sophisticated, it has been desired to mount more electronic components on printed wiring boards. Against this background, conventional single-sided printed wiring boards have a limit in mounting a large number of electronic components and the like within a predetermined size range. Recently, the use of double-sided printed wiring boards has been increasing remarkably for efficient mounting of electronic components due to the difficulty in forming conductive patterns.

Next, a method of manufacturing a general double-sided printed wiring board will be described with reference to manufacturing process diagrams shown in FIGS. 13 and 14 and a flowchart shown in FIG. First, FIGS. 13A and 13B
As shown in the figure, on the double-sided copper-clad laminate 3 formed by attaching copper foils 2a and 2b to both sides of an insulating base material 1 made of a synthetic resin such as an epoxy resin using an adhesive, the copper foils 2a and 2b are laminated. A hole 3a for electrically connecting (conducting) the holes 2b is drilled by a drill or the like, and then a catalyst for electroless plating (not shown) is formed on the surfaces of the copper foils 2a and 2b and the wall surfaces of the holes 3a. ).

[0004] Next, in order to perform thick plating, which will be described later, on the double-sided copper-clad laminate 3 provided with a catalyst as described above,
By performing the electroless copper plating treatment, as shown in FIG. 13C, the thin copper plating 4 is applied to the surfaces of the copper foils 2a and 2b and the wall surfaces of the through holes 3a. Thereafter, electrolytic copper plating is performed on the double-sided copper-clad laminate 3 on which the thin-film copper plating 4 has been applied, as shown in FIG.
Thick copper plating 5 is applied to electrically connect (conduct) the front and back surfaces of the double-sided copper-clad laminate 3.

[0005] As described above, the double-sided copper-clad laminate 3
After conducting the conduction process on the front and back surfaces of FIG. 14, in order to form a conductor pattern of a predetermined shape on the double-sided copper-clad laminate 3, FIG.
As shown in (a), an etching resist (corrosion-resistant material) is formed on a portion (on the thick copper plating 5) where the conductor pattern is to be formed by a known image forming method such as a screen printing method or a photographic method. The protective layer 6 is printed and cured.

Next, as shown in FIG. 14B, the copper foils 2a and 2b and the copper plating
An etching process is performed to remove an unnecessary portion of No. 5, that is, a portion which does not constitute a conductor pattern, and thereafter, the etching resist 6 is removed, thereby obtaining FIG.
As shown in (c), the double-sided printed wiring board 8 provided with the conductor pattern 7 having a predetermined shape was manufactured.

[0007]

However, when manufacturing a double-sided printed wiring board as described above, in order to connect the copper foil on the front and back sides, the front and back sides of the double-sided copper-clad laminate must be connected in advance. Through holes must be drilled in necessary parts by a drill or the like, and when drilling the through holes, a large amount of metal (copper foil) or resin (insulating substrate) dust is generated. For this reason, there is a problem that, for example, when the dust is sucked by the worker during the work, the worker's health is seriously affected.

When connecting the copper foil on the front and back sides,
A catalyst for electroless plating is applied to the surface of the copper foil and the wall surface of the through hole in advance, and thereafter, an electroless copper plating process for forming a thin film and an electrolytic copper plating process for thick plating are performed.
Since the back side was electrically connected,
Connection of the copper foil on the back side requires at least two types of plating equipment, and as a result, there has been a problem that the equipment for manufacturing a double-sided printed wiring board is large and uneconomical. In addition, the chemical waste liquid generated in the plating facility may have a bad influence on the natural environment, so that its handling and treatment is very troublesome.

Further, the work of connecting the copper foils on the front and back sides requires a drilling step, a catalyst applying step, an electroless copper plating step, and an electrolytic copper plating step, as described above. In addition, the work process is complicated, and the production of a double-sided printed wiring board requires a great deal of labor and time.

In view of the above-mentioned various problems, the present invention simplifies the manufacturing process by omitting a drilling step and a plating step for generating a large amount of dust and chemical waste liquid, thereby forming a double-sided printed wiring board. And a method for producing the same.

[0011]

According to a first aspect of the present invention, there is provided a double-sided printed wiring board, comprising: a pair of copper foils bonded to each other with an adhesive as an insulating member interposed therebetween; A laminated laminate is formed, and the pair of copper foils are pressed and pressed from one or both sides at a predetermined portion, or are melted and electrically connected.

According to a second aspect of the present invention, there is provided a method for manufacturing a double-sided printed wiring board, comprising: bonding a pair of copper foils each having an adhesive applied to one end face thereof with the adhesive faces facing each other. A step of forming a thin-plated double-sided copper-clad laminate, a step of printing an etching resist on the front and back surfaces of the double-sided copper-clad laminate, and a step of etching the double-sided copper-clad laminate by printing the etching resist. A step of forming a conductor pattern of a predetermined shape by etching using, and a step of removing an etching resist after the formation of the conductor pattern, and a step of removing copper foil on the front and back surfaces of the double-sided copper-clad laminate at a predetermined portion. And a front / back surface connection processing step of electrically connecting.

Further, according to a second aspect of the present invention, there is provided a double-sided printed wiring board manufacturing method, comprising: bonding a pair of copper foils each having an adhesive applied to a portion of one end surface which does not require front / back connection; Forming a double-sided copper-clad laminate in the form of a thin plate by adhering them in a state of facing each other, printing an etching resist on the front and back surfaces of the double-sided copper-clad laminate, and printing the etching resist. Etching the exposed double-sided copper-clad laminate using an etchant to form a conductor pattern having a predetermined shape; removing the etching resist after the formation of the conductor pattern; and A front and back surface connection processing step of electrically connecting the copper foil on the back surface at a predetermined portion;

[0014] In the front / back connection process, a metal plate provided with a micro-bar-like projection at a portion to be connected to the front / back surface is provided on one or both copper foils of the double-sided copper-clad laminate. In this state, by applying a predetermined pressure to one or both copper foils of the double-sided copper-clad laminate through the protrusions at a predetermined temperature under the predetermined temperature, the one copper foil is turned into the other copper foil. It is characterized in that the copper foil is electrically connected to the side or both by pressing and pressing.

Further, in the front / back connection process, a metal plate provided with a micro-bar-shaped projection at a portion where front / back connection is performed is provided on one or both copper foils of the double-sided copper-clad laminate. In this state, by applying a predetermined voltage to the protrusion at a predetermined temperature at a predetermined temperature, the one copper foil is electrically connected to the other copper foil side, or both copper foils are melted. It is characterized in that it is connected.

According to the present invention, for example, a metal plate having an extremely fine rod-shaped projection is brought into contact with one copper foil of a double-sided copper-clad laminate formed using a pair of copper foils coated with an adhesive. ,
Applying a specified pressure at a specified temperature, or
By applying a predetermined voltage, the one copper foil is deformed (pressed / pressed or melted) on the other copper foil side to connect the front and back surfaces, thereby forming a double-sided printed wiring board having a simple structure. It was formed. Further, the manufacturing process can be favorably simplified, and the double-sided printed wiring board can be manufactured quickly and easily.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the manufacturing process diagrams of FIGS. 1 to 4 and the flowchart of FIG. First, as shown in FIGS. 1A and 1B, an adhesive (for example, 50 μm) 12 is applied to one end surface.
A pair of copper foils (for example, 20μ) 13a, 13
b is bonded with the adhesives 12 facing each other to form a thin plate-shaped double-sided copper-clad laminate 14.

Next, in order to form a conductor pattern of a predetermined shape on the double-sided copper-clad laminate 14, as shown in FIG. 2 (a), copper foils 13a,
The etching resist 15 is printed on the portion 13b by a well-known image forming method and is cured.

Next, as shown in FIG. 2B, an etching process is performed to remove unnecessary portions of the copper foils 13a and 13b, that is, portions that do not form a conductor pattern, using an etching solution. After that, by removing the etching resist 15, as shown in FIG.
A conductor pattern 16 having a predetermined shape is formed on the double-sided copper-clad laminate 14.
a and 16b are formed.

Subsequently, after the conductor patterns 16a and 16b having a predetermined shape are formed as described above, as shown in FIG. 3A, the conductor pattern 1 on the front side (upper side of FIG. 3A) is formed.
6a, an extra-fine rod-shaped projection 17 having an arc-shaped tip.
The metal plate 17 provided with a is abutted through the projection 17a, and the flat metal plate 18 is abutted on the conductor pattern 16b on the back side (lower side in FIG. 3A). By doing so, the double-sided copper-clad laminate 14 is
(The ultra-fine rod-shaped projections 17a of the metal plate 17 are provided only at the portions where the front and back surfaces of the conductor patterns 16a and 16b are connected. The length of the projections 17a is set to the length of the conductor pattern 16a. , 16b can be securely connected, and the length is set so as not to penetrate the double-sided copper-clad laminate 14).

In this state, at a predetermined temperature (for example, a temperature at which the adhesive 12 softens), a predetermined pressure (copper foil 13a, 1
3b is applied to such an extent that the conductive pattern 16a is not broken), and as shown in FIG.
Conductor pattern 1 on the back side while pushing (deforming)
6b is pressed and pressed against the conductor pattern 16a on the front side.
Is electrically connected to the conductor pattern 16b on the back side.

At this time, the adhesive 12 is gradually softened by being placed at a predetermined temperature, so that if a predetermined pressure is applied to the conductor pattern 16a on the front side, the conductor pattern 16a can easily become The adhesive 12 is pushed away and pressed / pressed against, so that it can be satisfactorily connected (conductive) to the conductor pattern 16b on the back surface side.

Then, after the adhesive 12 is hardened (for example, heated to 120 ° C.), the pressurized state of the double-sided copper-clad laminate 14 by the metal plate 17 is released, whereby FIG. As shown in FIG.
Double-sided printed wiring board 11 in which 6a and 16b are pressed and connected
(Note that the adhesive 12 cures, thereby performing the same role as the insulating base material 1 in the related art).

As described above, in the first embodiment, the thin plate-shaped double-sided copper-clad laminate 14 is sandwiched between the metal plate 17 having the fine rod-shaped projections 17a and the flat metal plate 18. By applying a predetermined pressure to the metal plate 17 at a predetermined temperature, the conductor pattern 16a on the front side is formed.
Is connected to the conductor pattern 16b on the back side by pressing / pressing, so that the hole-forming step and the plating step are not required, and the conductor pattern 16
a and 16b can be connected, and as a result, the double-sided printed wiring board 11 can be manufactured quickly and economically without generating a large amount of dust or chemical waste liquid.

Next, a second embodiment of the present invention will be described with reference to manufacturing process diagrams of FIGS. 6 to 9 and a flowchart of FIG. The difference between the second embodiment and the first embodiment is that the adhesive is applied only to a portion of the copper foil that does not need to be connected to the front and back surfaces. The same members as those in the first embodiment will be described using the same reference numerals.

First, as shown in FIGS. 6 (a) and 6 (b), a pair of copper foils 13a, 13b coated with an adhesive 12a is applied only to a portion of one end surface which does not require connection between the front and back surfaces.
Is bonded in a state where the adhesives 12a are opposed to each other to form a thin plate-shaped double-sided copper-clad laminate 14a having a space S at a connection portion on the front and back surfaces.

Next, in order to form a conductor pattern of a predetermined shape on the double-sided copper-clad laminate 14a, as shown in FIG.
An etching resist 15 is printed on the portion 3b, followed by an etching process for removing unnecessary portions of the copper foils 13a and 13b using an etchant as shown in FIG. Thereafter, by removing the etching resist 15, as shown in FIG. 7C, conductor patterns 16a and 16b having a predetermined shape are formed on the double-sided copper-clad laminate 14a.

Subsequently, after the conductor patterns 16a and 16b having a predetermined shape were formed as described above, as shown in FIG. 8 (a), the double-sided copper-clad laminate 14a was formed into a projection 17a in the form of a fine rod. A predetermined pressure is applied to the metal plate 17 by using a pressing device or the like (not shown) at a predetermined temperature, as in the first embodiment, by sandwiching the metal plate 17 between the metal plate 17 and the flat metal plate 18. As a result, as shown in FIG. 8B, the conductor pattern 16a on the front side is pressed and pressed against the conductor pattern 16b on the back side by the projection 17a provided on the metal plate 17, and the conductor pattern on the front side is formed. Pattern 1
6a and the conductor pattern 16b on the back side are electrically connected (conductive).

Then, after the adhesive 12a is cured, the pressing state of the double-sided copper-clad laminate 14a by the metal plate 17 is released, as shown in FIG.
A double-sided printed wiring board 11a is formed by pressing and connecting the conductor patterns 16a and 16b on the front and back surfaces.

As described above, in the second embodiment, the adhesive 12 is applied only to a portion that does not require front / rear connection.
a is applied to the pair of copper foils 13a and 13b with the adhesives 12a facing each other to form a thin plate-shaped double-sided copper-clad laminate 14a, Is sandwiched between a metal plate 17 having an extra-fine rod-shaped projection 17a and a flat metal plate 18, and a predetermined pressure is applied to the metal plate 17 at a predetermined temperature to connect the front and back surfaces. Since the space S in which the adhesive 12a does not exist is formed in the connection portion on the front and back surfaces, the conductor pattern 16a on the front surface is not disturbed by the adhesive 12a. Good connection with the conductor pattern 16b on the back surface side is possible.

In the first and second embodiments, the conductive patterns 16a, 16b
For example, after the thin plate-shaped double-sided copper-clad laminates 14 and 14a are formed and before the etching process is performed, the double-sided copper-clad laminate 1 is connected.
Metal plate 1 having ultrafine rod-shaped projections 17a, 4 and 14a
7 and a flat metal plate 18, and by applying a predetermined pressure to the metal plate 17 at a predetermined temperature, the copper foils 13 a and 13 b are connected in advance, and thereafter, an etching process is performed. Alternatively, the double-sided printed wiring boards 11 and 11a having the conductor patterns 16a and 16b of a predetermined shape with the front and back surfaces connected may be formed.

As described above, even if the copper foils 13a and 13b are connected before the etching process,
Since the connection portions a and 13b are protected by the etching resist 15 during the etching process, they are not removed by the etching process. Therefore, the copper foil 13
The connection work of a and 13b may be performed before or after the etching process, and the work can be given flexibility.

The conductor patterns 16a, 1 on the front and back sides
6b, the double-sided copper-clad laminates 14 and 14a are sandwiched between a pair of metal plates 17 and 18 and a predetermined pressure is applied to the metal plate 17 at a predetermined temperature to form the conductor patterns 16a on the front and back surfaces. , 16b are connected by mechanically pressing them, for example, as shown in FIGS. 11 (a) and 12 (a).
With the double-sided copper-clad laminates 14, 14 a being sandwiched between the metal plates 17, 18, the ultrafine rod-shaped projections 17
By applying a predetermined voltage to a through a lead wire or the like (not shown), as shown in FIG. 11B and FIG. Conductor pattern 16 on the front and back, like welding
a and 16b may be electrically melted and connected (when the front and back sides are connected in one place, the double-sided printed wiring boards 11 and 11a are moved or
The metal plate 17 on which the protrusions 17a are formed is moved to perform a connection operation for another front / back connection portion).

As described above, the double-sided copper-clad laminate 1 in the form of a thin plate
4 and 14a are sandwiched between a pair of metal plates 17 and 18,
By applying a predetermined voltage to the protrusion 17a provided on the metal plate 17, the conductor patterns 16a, 1
By electrically melting and connecting the conductive patterns 6b, the conductor patterns 16a and 16b can be connected more reliably and satisfactorily.

Furthermore, the conductor patterns 16a, 16 on the front and back surfaces
6b, one conductor pattern 16a
Is described in connection with the other conductor pattern 16b, but the conductor patterns 16a, 16b may be pressed from both at the same location to connect the conductor patterns 16a, 16b by pressing them together. When the conductor patterns 16a and 16b on the front and rear surfaces are melted and connected (see paragraph [0033]), the fine rod-shaped projections 17a are brought into contact with the same portions of the conductor patterns 16a and 16b from both sides,
The present invention is established even when a predetermined voltage is applied to one of the protrusions 17a to melt and connect the conductor patterns 16a and 16b.

In the second embodiment, a pair of copper foils 13a and 13b coated with an adhesive 12a only at a portion where connection between the front and back surfaces is not performed is subjected to, for example, a bonding process under a predetermined reduced pressure. By forming a thin plate-shaped double-sided copper-clad laminate 14a and thereafter placing the double-sided copper-clad laminate 14a under normal pressure (atmospheric pressure), the copper foils 13a and 13b are
Utilizing the space S portion where the adhesive 12a does not exist,
The copper foils 13a and 13b on the front and back surfaces may be connected by deforming the double-sided copper-clad laminate 14a by the atmospheric pressure applied thereto.

Further, in the embodiment of the present invention, the case where a double-sided printed wiring board is manufactured has been described.
The above manufacturing method can be applied to the manufacture of a multilayer printed wiring board.

[0038]

According to the present invention, as described above, a thin double-sided copper-clad laminate is formed by using a pair of copper foils coated with an adhesive, and this laminate has an ultrafine rod-shaped projection. By sandwiching between a metal plate and a flat metal plate and applying a predetermined pressure at a predetermined temperature or applying a predetermined voltage, for example, the copper foil on the front surface side is The connection between the front and back surfaces is performed by pressing and contacting the substrate, so that a double-sided printed wiring board having a simple structure can be obtained. In addition, it is possible to connect the front and back surfaces without the need for a drilling step or a plating step as in the conventional case. As a result, the double-sided printed wiring board has a negative effect on the human body and the natural environment. The production can be carried out with the generation of dust and chemical waste liquid to be provided suppressed.

Moreover, according to the present invention, as described above,
The copper foil on the front and back sides can be connected by a simple method of sandwiching the double-sided copper-clad laminate between a pair of metal plates and applying a predetermined pressure at a predetermined temperature or applying a predetermined voltage. As compared to the conventional case where the front and back surfaces are connected by performing a drilling process and a plating process as in the related art, it is possible to greatly reduce the time, and as a result, the manufacturing process is effectively simplified, A double-sided printed wiring board can be manufactured quickly and easily.

In the second embodiment of the present invention, an adhesive is applied only to a portion of the copper foil that does not need to be connected to the front and back surfaces, so that a thin double-sided copper-clad laminate is formed. Therefore, at the time of the front / back connection of the copper foil, since no adhesive is present at the front / back connection portion of the copper foil, the adhesive does not disturb the front / back connection. As a result, the connection work on the front and back surfaces can be performed well, quickly and reliably.

Further, according to the manufacturing method of the present invention, the operation of connecting the copper foil on the front and back surfaces is performed before the etching process or
Since it is only necessary to perform the process later, the degree of freedom in the manufacturing process of the double-sided printed wiring board is increased, which is convenient.

[Brief description of the drawings]

FIG. 1 is a diagram showing a manufacturing process of a double-sided printed wiring board according to a first embodiment of the present invention, in which (a) is a cross-sectional view showing a state before bonding a pair of copper foils to which an adhesive has been applied;
(B) is a sectional view showing a state in which a pair of copper foils are bonded to form a double-sided copper-clad laminate.

2 (a) is a cross-sectional view showing a state where an etching resist is printed, FIG. 2 (b) is a cross-sectional view showing a state where an etching processing is performed, and FIG. It is sectional drawing which shows the state which formed.

FIG. 3A is a cross-sectional view showing a state before the front-back connection is performed, and FIG. 3B is a cross-sectional view showing a state after the front-back connection is performed.

FIG. 4 is a cross-sectional view showing a double-sided printed wiring board manufactured by the manufacturing method according to the first embodiment of the present invention.

FIG. 5 is a flowchart schematically showing a manufacturing process of the double-sided printed wiring board according to the first embodiment of the present invention.

FIG. 6 is a view showing a manufacturing process of the double-sided printed wiring board according to the second embodiment of the present invention, wherein (a) is a cross-sectional view showing a state before bonding a pair of copper foils coated with an adhesive;
(B) is a sectional view showing a state in which a pair of copper foils are bonded to form a double-sided copper-clad laminate.

7A is a cross-sectional view showing a state in which an etching resist is printed, FIG. 7B is a cross-sectional view showing a state in which the etching resist is applied, and FIG. It is sectional drawing which shows the state which formed.

FIG. 8A is a cross-sectional view showing a state before the front-back connection is performed, and FIG. 8B is a cross-sectional view showing a state after the front-back connection is performed.

FIG. 9 is a sectional view showing a double-sided printed wiring board manufactured by a manufacturing method according to a second embodiment of the present invention.

FIG. 10 is a flowchart schematically showing a manufacturing process of a double-sided printed wiring board according to the second embodiment of the present invention.

FIGS. 11A and 11B are diagrams showing a modification of the front / back connection process in the first embodiment of the present invention, wherein FIG. 11A is a cross-sectional view showing a state before front / back connection is performed, and FIG. It is sectional drawing which shows the state which performed front-back connection.

FIGS. 12A and 12B are diagrams showing a modification of the front / back connection process in the second embodiment of the present invention, wherein FIG. 12A is a cross-sectional view showing a state before front / back connection is performed, and FIG. It is sectional drawing which shows the state which performed front-back connection.

13 (a) is a cross-sectional view of a double-sided copper-clad laminate, and FIG. 13 (b) is a cross-sectional view of a double-sided copper-clad laminate in which through holes are formed. Figure, (c)
Is a cross-sectional view showing a state in which a thin-film copper plating is applied to a double-sided copper-clad laminate provided with a catalyst, and (d) is a thick copper plating on a double-sided copper-clad laminate in which a thin-film electroless copper plating is applied. It is sectional drawing which shows the state which performed.

FIG. 14A is a cross-sectional view showing a state in which an etching resist is printed on a double-sided copper-clad laminate in which front and back surfaces are connected, and FIG. 14B is a cross-sectional view showing a state in which the etching processing is performed. And (c) is a sectional view showing a state where the etching resist has been removed.

FIG. 15 is a flowchart schematically showing a manufacturing process of a conventional double-sided printed wiring board.

[Explanation of symbols]

 11, 11a Double-sided printed wiring board 12, 12a Adhesive 13a, 13b Copper foil 14, 14a Double-sided copper-clad laminate 16a, 16b Conductive pattern 17, 18 Metal plate 17a Projection

Claims (5)

[Claims] 1. A double-sided copper-clad laminate is formed by adhering a pair of copper foils with an adhesive as an insulating member interposed therebetween, and the pair of copper foils are placed at a predetermined portion on one or both sides. A double-sided printed wiring board characterized by being electrically connected by being pressed or pressed or melted. 2. A step of forming a thin double-sided copper-clad laminate by bonding a pair of copper foils each having an adhesive applied to one end surface thereof with their adhesive surfaces facing each other; A step of printing an etching resist on the front and back surfaces of the double-sided copper-clad laminate, and a step of etching the double-sided copper-clad laminate printed with the etching resist using an etchant to form a conductor pattern of a predetermined shape. And after the formation of the conductor pattern, a step of removing the etching resist, and a front and back surface connection processing step of electrically connecting the copper foil on the front and back surfaces of the double-sided copper-clad laminate at predetermined sites. A method for manufacturing a double-sided printed wiring board, comprising: 3. A thin plate-shaped double-sided copper foil is formed by bonding a pair of copper foils each having an adhesive applied to a portion of one end face that does not require front-to-back connection, with the adhesive faces facing each other. Forming a clad laminate, printing an etching resist on the front and back surfaces of the double-sided copper-clad laminate, and etching the double-sided copper-clad laminate printed with the etching resist using an etchant. Forming a conductor pattern of a predetermined shape, and after forming the conductor pattern,
A double-sided print comprising: a step of removing an etching resist; and a front-back connection processing step of electrically connecting copper foils on the front and back surfaces of the double-sided copper-clad laminate at predetermined portions. Manufacturing method of wiring board. 4. The front / rear surface connection processing step includes applying a metal plate provided with a micro-bar-shaped protrusion to a part where the front / rear surface connection is performed on one or both copper foils of the double-sided copper-clad laminate. contact,
In this state, by applying a predetermined pressure to one of the double-sided copper-clad laminates or both copper foils via the protrusions at a predetermined temperature, the one copper foil is moved to the other copper foil side. 4. The method for manufacturing a double-sided printed wiring board according to claim 2, wherein both copper foils are pressed and pressed to be electrically connected. 5. The front / rear surface connection processing step includes applying a metal plate provided with an ultrafine rod-shaped projection to a part where the front / rear surface connection is to be made on one or both copper foils of the double-sided copper-clad laminate. contact,
In this state, by applying a predetermined voltage to the protrusion at a predetermined temperature, the one copper foil is electrically connected to the other copper foil side, or both copper foils are melted. The method for manufacturing a double-sided printed wiring board according to claim 2 or 3, wherein