JPH1041635A - Single-sided circuit board for multilayer printed wiring board, its manufacture, and multilayer printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique which is useful for effectively manufacturing a multilayer printed wiring board having interstitial via hole structure with high yield. SOLUTION: In a single-sided circuit board for a multilayer printed wiring board, an insulating hard board 2 has a conducting circuit 3 on one surface, and via holes 6 turning to interstitial via holes are formed by filling holes which penetrate the board 2 and reach the conducting circuit 3 with conductive paste 5. The above single-sided circuit board 1 for a multilayer printed wiring board has a characteristic that penetrating pin holes 7 are arranged in the conducting circuit parts being in contact with the conductive paste 5. A multilayer printed wiring board of an IVH structure is constituted of the single- sided circuit board 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-sided circuit board for a multilayer printed wiring board, a method for manufacturing the same, and a multilayer printed wiring board, and more particularly, to a connection reliability in which holes for via holes are reliably filled with a conductive paste. This is a proposal for a single-sided circuit board that excels in performance.

[0002]

2. Description of the Related Art A conventional multilayer printed wiring board is constituted by a laminate obtained by stacking a copper-clad laminate and a prepreg on each other and integrating them. This laminate has a surface wiring pattern on its surface and an inner layer wiring pattern between the interlayer insulating layers. These wiring patterns are electrically connected to each other between the inner layer wiring patterns or between the inner layer wiring pattern and the surface wiring pattern via through holes formed in the thickness direction of the laminate.

However, in the multilayer printed wiring board having the through-hole structure as described above, since it is necessary to secure an area for forming the through-hole, it is difficult to increase the component mounting density. There is a drawback in that it is not possible to sufficiently cope with the demands for ultra-miniaturization of devices, narrow pitch packages, and practical use of MCMs. Therefore, recently, instead of the multilayer printed wiring board having the through-hole structure as described above, a multilayer printed wiring board having an interstitial via hole (IVH) structure which can easily cope with miniaturization and high density of electronic equipment has been developed. Development is underway.

[0004] The multilayer printed wiring board having the IVH structure is a printed wiring board having a structure in which conductive via holes for connecting conductive layers are provided in each interlayer insulating layer constituting a laminate. That is, this wiring board is electrically connected between the inner wiring patterns or between the inner wiring pattern and the surface wiring pattern by via holes (buried via holes or blind via holes) that do not penetrate the wiring board. Therefore, the multilayer printed wiring board having the IVH structure does not need to particularly provide a region for forming a through hole, and can easily realize miniaturization and high density of an electronic device.

[0005] With respect to such a multilayer printed wiring board having an IVH structure, for example, see page 57 of the ninth circuit packaging academic conference conference proceedings (March 2, 1995), the multi-layer printed wiring board having an all-layer IVH structure is described. Proposals for plate development have been reported. The proposed multilayer printed wiring board uses high-speed micro via hole processing technology using carbon dioxide gas laser, adopts aramid nonwoven fabric and epoxy resin composite material as substrate material, interlayer connection technology by filling conductive paste,
And is manufactured by the following process (see FIG. 1).

First, a material in which an aramid nonwoven fabric is impregnated with an epoxy resin is used as a prepreg, and the prepreg is perforated with a carbon dioxide gas laser, and then the hole thus obtained is filled with a conductive paste. (See FIG. 1 (a)). Next, copper foil is placed on both sides of the prepreg, and heated and pressed by a hot press. This allows
The epoxy resin and the conductive paste of the prepreg are cured and the copper foils on both sides are electrically connected to each other (FIG. 1 (b)
reference). Then, by patterning the copper foil by an etching method, a hard double-sided substrate having via holes can be obtained (see FIG. 1 (c)).

[0007] The double-sided substrate thus obtained is formed into a multilayer as a core layer. Specifically, on both sides of the core layer,
The prepreg filled with the conductive paste and the copper foil are sequentially laminated while being aligned, hot-pressed again, and then the uppermost copper foil is etched to obtain a four-layer substrate (FIG. 1 (d)). , (e)). In the case of further multi-layering, the above steps are repeated to obtain a six-layer or eight-layer substrate.

[0008] The IV according to the prior art as described above
H-structure multilayer printed wiring board is heated by hot press,
The pressing step and the patterning step of the copper foil by etching must be repeated many times, so that the manufacturing process becomes complicated and the manufacturing takes a long time. Moreover, in the multilayer printed wiring board having the IVH structure obtained by such a manufacturing method, it is difficult to confirm the patterning defect of the copper foil in the manufacturing process. When the ning failure occurs, the entire wiring board as a final product becomes defective. In other words, in the above-described conventional manufacturing process, if a defective product is produced even in one of the laminating steps, it must be disposed of another good laminating step, which tends to deteriorate the manufacturing efficiency or the manufacturing yield. There was a fatal drawback.

On the other hand, the present inventors have previously proposed a single-sided circuit board for a multilayer printed wiring board which is effectively used for efficiently manufacturing a multilayer printed wiring board having an IVH structure at a high yield. On the other hand, a conductor circuit is formed on one surface of the substrate, and an adhesive layer is formed on the other surface, and the substrate and the adhesive layer penetrate these layers and come into contact with a conductor. The present invention proposes a single-sided circuit board for a multilayer printed wiring board, characterized in that a hole is provided to form a via hole filled with a conductive paste.
As a multilayer printed wiring board having a VH structure, a multilayer printed wiring board in which at least one of circuit boards electrically connected via an IVH is formed of the single-sided circuit board has been proposed. Then, using the single-sided circuit board, the IVH
As a method of manufacturing a multilayer printed wiring board having a structure, Forming a conductive circuit by etching a metal foil attached to one surface of an insulating hard substrate; Forming an adhesive layer on a surface opposite to the conductor circuit formed on one surface of the substrate; Forming a hole penetrating the insulating hard substrate and the adhesive layer and contacting a conductor, and filling the hole with a conductive paste to produce a single-sided circuit board; Laminating two or more of the single-sided circuit boards or laminating with another circuit board, and then using the adhesive layer provided on the board to integrate them into a multilayer by a single press molding, A method for manufacturing a multilayer printed wiring board characterized by passing through is proposed.

The single-sided circuit board according to this proposal does not fill the through hole of the insulating hard substrate with the conductive paste, but fills the hole where one side of the insulating hard substrate is closed with a conductor with the conductive paste. It is such a configuration. For this reason, the above proposed method of manufacturing a single-sided circuit board by filling such holes with a conductive paste has a new structure in which air is easily trapped in the via holes, and it is difficult to reliably fill the conductive paste. There were serious disadvantages. In particular, in recent circuit boards, it is necessary to provide a large number of holes of about 100,000 holes / m ² in one layer, and if the conductive paste is not completely filled even in one hole, the circuit board itself may be electrically connected poorly. Become. Therefore, in order to efficiently manufacture a multilayer printed wiring board having an IVH structure with a high yield, a stable supply of a single-sided circuit board having excellent connection reliability is indispensable. It was necessary to develop a technology that could reliably fill all holes with conductive paste.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and a main object of the present invention is to efficiently manufacture a multilayer printed wiring board having an IVH structure at a high yield. An object of the present invention is to provide a single-sided circuit board which is used effectively and has excellent connection reliability. Another object of the present invention is to propose a method for stably manufacturing a single-sided circuit board having excellent connection reliability. Still another object of the present invention is to provide a multilayer printed wiring board having an IVH structure constituted by the single-sided circuit board having excellent connection reliability.

[0012]

Means for Solving the Problems The inventor of the present invention has conducted intensive studies in order to achieve the above-mentioned object, and as a result, has completed the invention having the following features. (1) As a single-sided circuit board having excellent connection reliability, which is used effectively for efficiently manufacturing a multilayer printed wiring board having an IVH structure at a high yield, the present invention provides an insulating board having a conductor circuit on one side. In a single-sided circuit board for a multilayer printed wiring board in which a conductive paste is filled in a hole penetrating through the substrate and reaching the conductive circuit to form a via hole serving as an interstitial via hole with respect to the conductive hard substrate. The present invention proposes a single-sided circuit board for a multilayer printed wiring board, wherein a through-hole is provided in a conductor circuit portion in contact with a conductive paste. Here, the ratio (S2 / S1) of the area S2 of the through-pinhole to the area S1 of the conductor circuit in contact with the conductive paste is equal to the through-hole.
Desirably, it is in the range of 0.01 to 0.40, and it is desirable that the insulating hard substrate is formed at the same time as the boring process by laser irradiation.

(2) As a method for stably producing a single-sided circuit board having excellent connection reliability as described in the above (1), the present invention comprises at least the following steps: Forming a conductive circuit by etching a metal foil attached to one surface of an insulating hard substrate; Forming a hole penetrating through the insulating hard substrate and reaching the conductor circuit by irradiating the laser, and simultaneously forming a through-pin hole in the conductor circuit in contact with the hole; Filling the hole with a conductive paste. A method for manufacturing a single-sided circuit board is proposed.

(3) The present invention provides a multilayer printed wiring board having a structure in which laminated materials of a circuit board are electrically connected to each other through interstitial via holes. There is provided a multilayer printed wiring board comprising a single-sided circuit board having excellent connection reliability as described in the above (1).

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The single-sided circuit board for a multilayer printed wiring board according to the present invention is characterized in that it has a structure in which a through-hole is provided in a conductive circuit portion of a via hole in contact with a conductive paste. With such a structure, the air in the via hole escapes from the through-hole and the conductive paste can be reliably filled. As a result, a single-sided circuit board capable of reliably performing electrical connection between the conductor circuits of the circuit board, that is, excellent connection reliability required for efficiently manufacturing a multilayer printed wiring board having an IVH structure at a high yield. A single-sided circuit board can be reliably provided.

Here, in the single-sided circuit board of the present invention, the through-hole provided in the conductor circuit plays a role of discharging the air entrapped at the time of filling the conductive paste to the outside of the system. However, if the opening area of the through pinhole is increased, the entrained air can be discharged, but the electrical connection surface between the conductive circuit and the conductive paste decreases, resulting in poor connection of the circuit board itself. . Therefore, it is desirable that the through pinhole be smaller as far as the air trapped in the via hole can be reliably discharged. Therefore, the size of the through pinhole in the present invention is desirably in the range of 0.01 to 0.40 as the ratio (S2 / S1) of the area S2 of the through pinhole to the area S1 of the conductor circuit in contact with the conductive paste. .

In the single-sided circuit board of the present invention, the via hole plays a role of electrically connecting conductor circuits of each circuit board constituting the multilayer printed wiring board having the IVH structure. In particular, the conductive paste filled in the hole that comes into contact with the conductor circuit through the insulating hard substrate is closely adhered to the conductor circuit on the other laminated circuit board by thermosetting, and the respective conductor circuits are bonded. Make an electrical connection.

In the single-sided circuit board according to the present invention, the conductor circuit is a surface wiring pattern or an inner layer wiring pattern constituting a multilayer printed wiring board having an IVH structure. Such a conductive circuit is formed by etching a metal foil attached to one surface of an insulating hard substrate, and is preferably a single-sided copper-clad laminate formed by forming a copper foil on one surface of an insulating hard substrate. Is formed by etching the copper foil.

In such a single-sided circuit board according to the present invention, it is desirable that a hole penetrating through the insulating hard substrate and reaching the conductor circuit is formed by laser irradiation. The reason is that the hole for forming the via hole of the single-sided circuit board is advantageous to form a hole with a very small diameter as high as possible, and by applying a laser to the drilling process,
This is because holes having a small diameter can be easily formed at a high density. In particular, according to the laser drilling process, a through-hole for a conductor circuit, which is a characteristic feature of the present invention, can be formed simultaneously with the formation of the above-mentioned hole, and a single-sided circuit board having excellent connection reliability can be extremely easily formed. The inventor has newly found that it can be surely provided by a simple method. That is, if the center beam intensity of the laser is increased,
A penetrating pinhole can be formed in the conductor circuit simultaneously with the formation of the hole. This phenomenon was remarkable when the conductor layer was thin and the heat of the beam was difficult to escape.

The method for manufacturing a single-sided circuit board according to the present invention utilizing the characteristics of the laser includes at least the following steps: Forming a conductive circuit by etching a metal foil attached to one surface of an insulating hard substrate; Forming a hole penetrating through the insulating hard substrate and reaching the conductor circuit by irradiating the laser, and simultaneously forming a through-pin hole in the conductor circuit in contact with the hole; Filling the hole with a conductive paste.

Here, the laser used in the present invention includes:
Fourth of carbon dioxide laser, excimer laser and YAG laser
Harmonics and the like. In particular, the carbon dioxide laser is advantageous in that the processing speed is extremely high.

The single-sided circuit board according to the present invention as described above is individually manufactured in advance as a single-sided circuit board having a conductor circuit on which a predetermined wiring is formed, prior to manufacturing a multilayer printed wiring board having an IVH structure. You. Therefore, it is possible to confirm the presence or absence of a defective portion such as a conductor circuit before laminating these single-sided circuit boards. As a result, if the single-sided circuit board of the present invention is used, only a single-sided circuit board having no defective portion will be used. It can be manufactured with yield.

Further, if the single-sided circuit board of the present invention is used, it is not necessary to repeat the steps of stacking and hot-pressing prepregs as in the prior art. By utilizing the adhesive layer provided on the circuit board, it is possible to perform lamination and integration by a single hot press molding. That is, a multilayer printed wiring board having an IVH structure can be efficiently manufactured in a short time without repeating complicated steps.

The multi-layer printed wiring board having the IVH structure according to the present invention, which is efficiently manufactured at a high yield in this manner, has a multi-layer printed circuit having a structure in which the laminated materials of the circuit board are electrically connected to each other via the IVH. A wiring board,
At least one layer of the circuit board is constituted by the single-sided circuit board of the present invention described above.

Here, the single-sided circuit board constituting the multilayer printed wiring board of the present invention is desirably bonded to another circuit board via an adhesive layer or the like of the single-sided circuit board. As such another circuit board, any of the single-sided circuit board of the present invention and a conventionally known printed wiring board can be used.

The multilayer printed wiring board of the present invention can be formed by various processings generally performed on printed wiring boards, for example, formation of a solder resist on the surface, nickel / gold plating or soldering on the surface wiring pattern. Processing, drilling, cavity processing, through-hole plating and the like can be performed. Further, the multilayer printed wiring board of the present invention is used for mounting electronic components such as IC packages, bare chips, and chip components.

[0027]

FIG. 2 is a longitudinal sectional view of a single-sided circuit board according to an embodiment of the present invention. In this figure, the single-sided circuit board 1
Is composed of an insulating hard substrate 2, a conductive circuit 3 formed by etching a metal foil attached to one surface of the substrate, and an adhesive layer 4 formed on the surface of the substrate opposite to the conductive circuit. A single-sided circuit board in which an insulating hard substrate 2 and an adhesive layer 4 are provided with holes penetrating these layers and in contact with the conductor circuit 3 to form via holes 6 filled with a conductive paste 5; The conductor circuit 3 has a through pinhole 7.

FIG. 3 is a longitudinal sectional view of a single-sided circuit board according to another embodiment of the present invention. In this figure, a single-sided circuit board 1 is formed on an insulating hard substrate 2, a conductor circuit 3 formed by etching a metal foil adhered to one side of the board, and a surface of the conductor circuit and the substrate. A single-sided circuit board comprising an adhesive layer 4 and a via hole 6 filled with a conductive paste 5 in a hole penetrating the substrate and contacting the conductor circuit 3 in the insulating hard substrate 2; 3
Is provided with a through pinhole 7.

Here, it is preferable that the conductor circuit 3 is formed by etching a copper foil of a single-sided copper-clad laminate obtained by forming a copper foil on one side of an insulating hard substrate 2, for example. . Examples of the insulating hard substrate 2 include, for example,
A substrate obtained by curing a glass cloth epoxy resin, a glass nonwoven cloth epoxy resin, a glass cloth bismaleimide triazine resin, an aramid nonwoven cloth epoxy resin, or the like into a plate shape can be used. The adhesive layer 4 can be made of, for example, an epoxy-based, polyimide-based, bismaleimide-triazine-based, acrylate-based, or phenol-based resin adhesive. As the conductive paste, for example,
A conductive paste of copper, silver, gold, carbon, or the like can be used.

Next, a method of manufacturing the single-sided circuit board according to one embodiment of the present invention shown in FIG. 2 will be specifically described with reference to FIG. (1) First, an insulative hard substrate 12a having a metal foil 13 adhered to one side as shown in FIG. 4A is prepared. It is advantageous to use, for example, a single-sided copper-clad laminate as the insulating hard substrate 12a having the metal foil 13 adhered to one side.

(2) Next, the metal foil 13 is etched,
As shown in FIG. 4B, it is processed into a predetermined pattern shape. Thus, the conductor circuit 13a is formed. As this etching method, known general means can be adopted. When the conductor circuit 13a is used as an inner layer wiring pattern, the surface of the conductor circuit is improved by, for example, applying microetching, roughening plating, or applying double-sided roughened copper foil to improve the adhesion between layers. It is advantageous to roughen the surface by using the means described above.

(3) Next, on the surface of the insulating hard substrate 12a on which the conductor circuit 13a is formed, on the side opposite to the conductor circuit,
As shown in (c), an adhesive layer 14a is formed. The adhesive layer 14a can be formed by applying a predetermined resin adhesive by means of a roll coater, curtain coater, spray coater, screen printing, or the like, or by pre-curing, or by laminating an adhesive sheet. At this time, the thickness of the adhesive layer is advantageously in the range of 10 to 50 μm.

(4) Next, as shown in FIG. 4 (d), a hole 16 penetrating the adhesive layer 14a and the insulating hard substrate 12a in the thickness direction and contacting the conductor is formed. This hole 16 is preferably formed by irradiating a laser from the side of the adhesive layer 14a of the insulating hard substrate 12a. As the drilling machine for irradiating this laser, for example, a pulse oscillation type carbon dioxide laser machine can be used. By using such a carbon dioxide laser processing machine, 60 to 200 μmφ
Can be formed with high precision. As a result, via holes can be formed at a high density, and a small and high-density multilayer printed wiring board can be manufactured. In particular, in the single-sided circuit board of the present invention, for example,
By increasing the pulse energy of the laser,
A through-hole 17a is formed substantially at the center of the conductor circuit 13a. The area S2 of the penetrating pinhole 17a can be controlled within the range of 0.01 to 0.40 in the ratio (S2 / S1) to the area S1 of the conductor in contact with the conductive paste 5 by controlling the pulse energy of the laser to be irradiated. Adjust so that This prevents air from being trapped in the via hole, thereby making it possible to electrically connect the via hole and the conductor circuit 13a reliably. In order to clean the conductive circuit surface 18 (the surface in contact with the conductive paste 5) at the bottom of the hole 16, desmearing can be performed.

(5) Next, as shown in FIG.
16 is filled with the conductive paste 5 to produce the single-sided circuit board 11a. The method for filling the conductive paste 5 includes:
For example, a screen printing method using a metal mask can be adopted. At the time of filling, it is advantageous to form a protective mask around the hole 16 in order to form the via hole with high precision. The protective mask can be formed by laminating a film or paper on the surface of the adhesive layer 14a and making a hole together during the hole making process. Further, in order to realize a via hole having good connectivity with a conductor circuit serving as an inner layer of another circuit board to be superimposed, it is advantageous to fill the conductive paste 5 so as to slightly protrude from the hole 16. is there. The filled conductive paste 5
Is preferably precured in order to enhance the workability of the subsequent steps, and the protective mask is peeled off before lamination.

Next, using the single-sided circuit board according to the embodiment of the present invention shown in FIG. 2, the IVH according to the embodiment of the present invention is used.
One method of manufacturing a multilayer printed wiring board having a structure will be specifically described with reference to FIG. (1) First, a single-sided circuit board 1 (11a) of the present invention, which constitutes a multilayer printed wiring board having an IVH structure, is manufactured according to FIG. (2) In a similar process, the conductor circuits 13b, 13c, 13d are provided on one surface of the insulating hard substrates 12b, 12c, 12d.
And on the other side adhesive layers 14b, 14c, 14d
And the substrate and the adhesive layer are provided with holes 16 penetrating these layers and contacting the conductor circuit, and at the same time, the conductor circuit has through-pin holes 17b,
A single-sided circuit board 11 as shown in FIG. 5 in which via holes 17c and 17d are provided and filled with conductive paste 5 is formed.
b, 11c and 11d are prepared.

(3) Next, the single-sided circuit boards 11a, 11
b, 11c, and 11d are superimposed in a predetermined order while being aligned using guide holes and guide pins provided around the single-sided circuit board. Here, the conductor circuit 13c of the single-sided circuit board 11c is placed above the adhesive layer 14d of the single-sided circuit board 11d.
And a single-sided circuit board on the adhesive layer 14c.
The adhesive layer 14b of 11b is overlapped and the conductive circuit
The adhesive layer 14a of the single-sided circuit board 11a is overlaid on the upper side of 13b.

(4) After the single-sided circuit boards are overlaid in this manner, they are heated and pressed in a temperature range of 140 ° C. to 200 ° C. using a hot press, so that each single-sided circuit board is press-formed once. Are integrated in a multilayer. It is advantageous to use a vacuum hot press as the hot press. In this step, the single-sided circuit boards 11a, 11b, 11 superimposed via the adhesive layers 14a, 14b, 14c, 14d.
The layers c and 11d are integrated in a multilayer shape by the adhesive layers 14a, 14b, 14c and 14d being closely adhered and thermosetting. At the same time, the conductive paste is also brought into close contact with the corresponding conductor circuit and thermally cured, thereby forming a via hole, and
A multilayer printed wiring board having a VH structure is obtained (see FIG. 6).

FIG. 6 is a vertical sectional view of a multilayer printed wiring board having an IVH structure according to one embodiment of the present invention. In this figure, a multilayer printed wiring board includes insulating hard substrates 12a and 12a.
b, 12c, 12d, and conductor circuits 13a, 13b, 13c, formed by etching a metal foil attached to one side of the substrate.
13d, and an adhesive layer 14a, 14b, 14c, 14d formed on the surface of the substrate opposite to the conductor circuit. The insulating hard substrates 12a, 12b, 12c, 12d and the adhesive layers 14a, 14b,
In 14c and 14d, conductor circuits 13a, 13b, 13c, which penetrate through these layers and also have through-holes formed in the conductors are formed.
Single-sided circuit boards 11a, 11b, having via holes 6a, 6b, 6d filled with conductive paste 5 in holes contacting 13d.
11c, 11d are laminated, and the single-sided circuit boards 11a, 11b, 11
adhesive layers 14a, 14b, 14c, c, 11d respectively provided
This is a four-layer substrate joined together by 14d.

Here, the conductor circuit 13a of the single-sided circuit board 11a
The conductor circuit 13d of the single-sided circuit board 11d is formed in a predetermined wiring pattern shape, and is arranged as a surface wiring pattern on the upper surface or the lower surface of the multilayer printed wiring board. The conductor circuit 13b of the single-sided circuit board 11b and the conductor circuit 13c of the single-sided circuit board 11c are respectively formed in a predetermined wiring pattern shape, and are formed below the single-sided circuit board 11a of the multilayer printed wiring board or above the single-sided circuit board 11d. Are arranged as inner wiring patterns.

The via hole 6a is made of an insulating hard substrate.
The via hole 6b is formed so as to penetrate the insulating substrates 12b and 12c and the adhesive layers 14b and 14c in the thickness direction. The via hole 6d is formed penetrating the insulating substrate 12d and the adhesive layer 14d in the thickness direction, and is filled with the conductive paste 5 respectively. Among these via holes, 6a is a blind via hole for electrically connecting between a conductor circuit 13a as a surface wiring pattern and 13b as an inner wiring pattern, and a via hole 6b is a conductor circuit 13b as an inner wiring pattern. A via hole 6d is a blind via hole for electrically connecting between the conductor circuit 13c as the inner layer wiring pattern and the conductor circuit 13d as the surface wiring pattern. And both constitute an interstitial via hole.

The multilayer printed wiring board according to the present invention can mount various electronic components. For example, as shown by a two-dot chain line in FIG. 6, a chip component 8 such as an IC package or a bare chip is mounted on the multilayer printed wiring board. It can be mounted on a predetermined portion of the surface wiring pattern 13a and fixed by the solder 9.

[Other Embodiments] (1) In the above embodiment, a multi-layer printed wiring board in which four-layer single-sided circuit boards are superimposed has been described. The present invention can be practiced, and a single-sided printed circuit board, a double-sided printed circuit board, a double-sided through-hole printed circuit board, or a multilayer printed circuit board manufactured by a conventional method is laminated with the single-sided circuit board of the present invention to produce a multilayer printed wiring board. Can be. (2) In the embodiment, at the same time as performing the drilling process for forming a via hole by means of irradiating a laser, a through pinhole was also provided in the conductor circuit, but in the formation of the through pinhole, Mechanical means such as drilling and punching can also be applied. In this case, a drilling process for forming a via hole is performed by a method of irradiating a laser, and thereafter, a through-pin hole is formed in a conductor circuit in contact with the drilled hole by mechanical means such as drilling or punching. .

[0043]

As described above, in the single-sided circuit board for a multilayer printed wiring board according to the present invention, since the through-holes are provided in the conductor circuit in contact with the conductive paste of the via holes, the conductive paste is filled. Occasionally, air is not entrained in the via hole, and the electrical connection reliability with other circuit boards is excellent. Therefore, according to the present invention, it is possible to reliably provide a single-sided circuit board excellent in connection reliability required for efficiently manufacturing a multilayer printed wiring board having an IVH structure with a high yield. According to the method for manufacturing a single-sided circuit board according to the present invention, the through-pin holes can be efficiently formed by drilling using a laser, and a single-sided circuit board with excellent connection reliability can be formed by an extremely simple method. Can be provided stably.
Furthermore, since the multilayer printed wiring board of the present invention composed of the single-sided circuit board has a structure in which circuit boards are joined to each other by an adhesive layer or the like, as a high-density multilayer printed wiring board having an IVH structure, It can be easily provided with a high yield without using a complicated manufacturing method.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one manufacturing process of a multilayer printed wiring board according to a conventional technique.

FIG. 2 is a longitudinal sectional view showing one embodiment of a single-sided circuit board according to the present invention.

FIG. 3 is a longitudinal sectional view showing another embodiment of the single-sided circuit board according to the present invention.

FIG. 4 is a longitudinal sectional view illustrating an example of a manufacturing process of the single-sided circuit board.

FIG. 5 is a longitudinal sectional view showing one manufacturing process of the multilayer printed wiring board according to the present invention.

FIG. 6 is a longitudinal sectional view showing one embodiment of the multilayer printed wiring board according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Single-sided circuit board 2, 2a, 2b, 2c, 2d Insulating hard board 3, 3a, 3b, 3c, 3d Conductor circuit 4, 4a, 4b, 4c, 4d Adhesive layer 5 Conductive paste 6, 6a, 6b, 6d Via hole 7, 7a, 7b, 7c, 7d Through pinhole 8 Chip component 9 Solder 11a, 11b, 11c, 11d Single-sided circuit board 12a, 12b, 12c, 12d Insulating hard board 13 Metal foil 13a, 13b, 13c, 13d Conductor circuit 14a, 14b, 14c, 14d Adhesive layer 16 holes 17a, 17b, 17c, 17d Through-pin hole 18 Conductor circuit surface at bottom of hole

Claims (6)

[Claims] 1. An insulating hard substrate having a conductive circuit on one surface is filled with a conductive paste into a hole penetrating the substrate and reaching the conductive circuit to form a via hole serving as an interstitial via hole. The formed single-sided circuit board for a multilayer printed wiring board, wherein a through-hole is provided in a conductor circuit portion in contact with the conductive paste. 2. The multilayer print according to claim 1, wherein a ratio (S2 / S1) of the area S2 of the pinhole to the area S1 of the conductor circuit in contact with the conductive paste is in the range of 0.01 to 0.40. Single-sided circuit board for wiring board. 3. The single-sided circuit board for a multilayer printed wiring board according to claim 1, wherein the through-holes are formed at the same time as drilling of the insulating hard substrate by laser irradiation. 4. At least each of the following steps: Forming a conductive circuit by etching a metal foil attached to one surface of an insulating hard substrate; Forming a hole penetrating through the insulating hard substrate and reaching the conductor circuit by irradiating the laser, and simultaneously forming a through-pin hole in the conductor circuit in contact with the hole; Filling the hole with a conductive paste. A method for manufacturing a single-sided circuit board, the method comprising: 5. The penetrating pinhole is provided so that the ratio (S2 / S1) of the area S2 of the penetrating pinhole to the area S1 of the conductor circuit in contact with the conductive paste is in the range of 0.01 to 0.40. The manufacturing method as described. 6. A multilayer printed wiring board having a structure in which laminated materials of a circuit board are electrically connected to each other through interstitial via holes, wherein at least one of the circuit boards has a structure as defined in claim 1 or 2. A multilayer printed wiring board, comprising the single-sided circuit board according to any one of the preceding claims.