JPH0936551A - Single-sided circuit board for multilayer printed wiring board use, multilayer printed wiring board and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a multilayer printed wiring board of an interstitial via hole structure at a high yield and efficiently by a method wherein holes, which penetrate boards and bonding agent layers and come into contact with conductor circuits, are provided to form via holes filled with a conductive paste. SOLUTION: Conductor circuits 3a of a single-sided circuit board 7a are arranged on the surface on the upper side of a multilayer printed wiring board 1 and conductor circuits 3d of a single-sided circuit board 7d are arranged on the surface on the lower side of the board 1. Conductor circuits 3b of a single-sided circuit board 7b are arranged in the lower side of the board 7a and conductor circuits 3c of a single-sided circuit board 7c are arranged in the upper side of the board 7d. Via holes 6a are formed penetratingly an insulative hard board 2a and a bonding agent layer 4a, via holes 6b are formed penetratingly insulative boards 2b and 2c and bonding agent layers 4b and 4c, via holes 6d are formed penetratingly an insulative board 2d and a bonding agent layer 4d and a conductive paste 5 is filled in the respective via holes.

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 multilayer printed wiring board and a method of manufacturing the same, and more particularly, to a multilayer printed wiring board having an interstitial via hole structure with high yield and high efficiency. We propose a single-sided circuit board for a multilayer printed wiring board that is effective for manufacturing, a multilayer printed wiring board composed of this single-sided circuit board, and a method of manufacturing the same.

[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 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, it is difficult to increase the density of component mounting because it is necessary to secure a region for forming the through hole, and thus the portable electronic device is difficult. However, there is a drawback in that it is not possible to sufficiently meet the demands for miniaturization of devices and practical application of narrow pitch packages and 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, in this wiring board, the inner layer wiring patterns are electrically connected to each other, or the inner layer wiring patterns and the surface wiring patterns are electrically connected to each other by via holes (belly via holes or blind via holes) that do not penetrate the wiring substrate. 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)). When the number of layers is further increased, the above steps are repeated to form a 6-layer or 8-layer substrate.

[0008]

The drawbacks of the prior art described above are that the heating and pressing steps by hot pressing and the copper foil patterning step by etching must be repeated many times, which complicates the manufacturing process. That is, it takes a long time to manufacture. 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 conventional manufacturing process, if a defective product is produced even at one place in each laminating process, it is necessary to dispose of other good laminating processes, which is likely to cause deterioration of manufacturing efficiency or manufacturing yield. There was a fatal drawback.

An object of the present invention is to provide 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 with a high yield. Another object of the present invention is to provide a multi-layer printed wiring board having an IVH structure composed of the above single-sided circuit board. Still another object of the present invention is to propose a method for efficiently manufacturing a multilayer printed wiring board having an IVH structure using the above single-sided circuit board with a high yield.

[0010]

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. That is, (1) as a single-sided circuit board for a multilayer printed wiring board, which is effectively used for efficiently producing a multilayer printed wiring board having an IVH structure with a high yield, the present invention provides Conductor circuits are formed on one surface, and an adhesive layer is formed on the other surface, and holes are formed in the substrate and the adhesive layer so as to pass through these layers and contact the conductors. Provided is a single-sided circuit board for a multilayer printed wiring board, wherein a via hole filled with a conductive paste is formed. Here, it is desirable that the conductor circuit is formed by etching a copper foil of a single-sided copper-clad laminate.

(2) As a multilayer printed wiring board having an IVH structure composed of the single-sided circuit board described in (1) above, the present invention provides a laminated material of a circuit board which is electrically connected through interstitial via holes. In a multilayer printed wiring board having a structure in which the circuit board is connected to at least one layer of the circuit board, a conductive circuit is provided on one side of the insulative rigid board, and an adhesive layer is provided on the other side. And a single-sided circuit board in which a via hole filled with a conductive paste is formed by forming a hole penetrating these layers and in contact with a conductor in the substrate and the adhesive layer. A multilayer printed wiring board is provided.

(3) As a method for efficiently producing a multilayer printed wiring board having an IVH structure with a high yield by using the single-sided circuit board described in (1) above, the present invention includes: 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; A step of 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; Stacking two or more of the above single-sided circuit boards or stacking them together with another circuit board, and then using the adhesive layer of the boards to integrate them into a multilayer by a single press molding, We propose a method for manufacturing a multilayer printed wiring board, which is characterized in that Here, it is desirable that the hole penetrating the insulating hard substrate and the adhesive layer and contacting the conductor be formed by laser irradiation. Further, it is desirable that the conductor circuit is formed by etching the copper foil of a single-sided copper-clad laminate obtained by forming a copper foil on one surface of an insulating hard substrate.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The first embodiment of the present invention is IV
It is an object of the present invention to provide a single-sided circuit board for a multilayer printed wiring board, which is necessary for efficiently manufacturing a multilayer printed wiring board having an H structure with a high yield. That is, the single-sided circuit board for a multilayer printed wiring board according to the present invention, with respect to the insulating hard substrate,
A conductor circuit is formed on one surface of the substrate, and an adhesive layer is formed on the other surface, and holes are formed in the substrate and the adhesive layer so as to pass through these layers and contact the conductor. A via hole is provided and filled with a conductive paste.

Here, in the present invention, the adhesive layer constituting the one-sided circuit board is used for manufacturing the multilayer printed wiring board having the IVH structure.
Alternatively, it plays a role of bonding when bonding to another circuit board to be laminated to form a multilayer. In the present invention,
The via hole constituting the one-sided circuit board serves to electrically connect the conductor circuit of the one-sided circuit board to the conductor circuit on another circuit board to be laminated in manufacturing the multilayer printed wiring board having the IVH structure. Carry. In particular, the conductive paste filled in the holes penetrating the insulating hard substrate and the adhesive layer and contacting the conductor circuit is adhered by heat curing to the conductor circuit on another circuit substrate that is laminated adjacent to each other, respectively. Electrically connect the conductor circuit of. In the present invention, the conductor circuit forming the single-sided circuit board is a surface wiring pattern or an inner layer wiring pattern forming 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.

By using the single-sided circuit board having the above-described structure, it is possible to efficiently manufacture a multilayer printed wiring board having an IVH structure with a high yield. less than,
The method of the present invention for producing a multilayer printed wiring board using the single-sided circuit board according to the present invention will be described. That is,
The method of the present invention comprises the following steps: 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; A step of 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; Stacking two or more of the above single-sided circuit boards or stacking them together with another circuit board, and then utilizing the adhesive layer of the boards to integrate them into a multilayer by a single press molding, It is characterized by passing.

As described above, the feature of the method for manufacturing a multilayer printed wiring board according to the present invention is that the single-sided circuit boards having the conductor circuits on which predetermined wiring patterns are formed are individually manufactured in advance. Therefore, it is possible to confirm the presence or absence of a defective portion such as a conductor circuit before stacking these single-sided circuit boards. Therefore, only the single-sided circuit board having no defective portion is used in the stacking step. As a result, according to the method of the present invention, defects are less likely to occur in the manufacturing stage, and the multilayer printed wiring board having the IVH structure can be manufactured with a high yield.

Further, according to the method for manufacturing a multilayer printed wiring board according to the present invention, it is not necessary to repeat the steps of stacking prepregs and hot-pressing as in the prior art, and stacking a single-sided circuit board with another circuit board. In addition, by using the adhesive layer provided on the one-sided circuit board, it is possible to laminate and integrate them by a single hot press molding. That is, according to the method of the present invention, a multilayer printed wiring board having an IVH structure can be efficiently manufactured in a short time without repeating complicated steps.

Here, it is preferable that the hole penetrating the insulating hard substrate and the adhesive layer and contacting the conductor is formed by laser irradiation. The reason is that the holes for forming the via holes of the single-sided circuit board are advantageously formed with a high-density hole as small as possible. Can be easily and densely formed. Further, the laser drilling process can drill a hole that penetrates only the insulating hard substrate and the adhesive layer without damaging the conductor circuit. As a result, instead of providing a hole penetrating the prepreg substrate as in the prior art, a hole whose one end is closed by a conductor circuit is formed.By filling the hole with a conductive paste, the via hole is formed. Since the conductor circuit makes surface contact with the conductor circuit, reliable conduction can be obtained.

In the multi-layer printed wiring board having the IVH structure according to the present invention manufactured as described above, at least one layer of the circuit board forming the wiring board is provided with respect to the insulating hard board.
A conductor circuit is formed on one surface of the substrate, and an adhesive layer is formed on the other surface, and holes are formed in the substrate and the adhesive layer so as to pass through these layers and contact the conductor. It is characterized in that it is constituted by a single-sided circuit board provided with a via hole filled with a conductive paste.

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

The multilayer printed wiring board of the present invention is subjected to various kinds of processing 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, etc. 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.

[0022]

FIG. 2 is a longitudinal sectional view of a multilayer printed wiring board according to one embodiment of the present invention. In this figure, the multilayer printed wiring board 1 comprises an insulating hard substrate 2a, 2b, 2c, 2d and conductor circuits 3a, 3b, 3c, 3d formed by etching a metal foil attached to one surface of the substrate. And an adhesive layer 4a, 4b, 4c, 4d formed on the surface of the substrate opposite to the conductor circuit, the insulating hard substrate 2a, 2b, 2c, 2d and the adhesive layer 4a, 4
Via holes 6a, 6 in which conductive paste 5 is filled in holes penetrating b, 4c, 4d and contacting conductor circuits 3a, 3b, 3c, 3d
Single-sided circuit boards 7a, 7b, 7c, 7d having b, 6d are laminated, and the single-sided circuit boards 7a, 7b, 7c, 7d are respectively bonded by adhesive layers 4a, 4b, 4c, 4d. It is a four-layer substrate.

Here, the conductor circuit 3a of the one-sided circuit board 7a and the conductor circuit 3d of the one-sided circuit board 7d are respectively formed in a predetermined wiring pattern shape, and surface wiring is performed on the upper surface or the lower surface of the multilayer printed wiring board 1. Arranged as a pattern. Further, the conductor circuit 3b of the single-sided circuit board 7b and the conductor circuit 3c of the single-sided circuit board 7c are each formed in a predetermined wiring pattern shape, and the single-sided circuit board 7a of the multilayer printed wiring board 1 is formed.
Is arranged as an inner layer wiring pattern on the lower side or the upper side of the single-sided circuit board 7d. The conductor circuits 3a, 3b, 3c, 3d
Is preferably formed by etching the copper foil of a single-sided copper-clad laminate obtained by forming a copper foil on one surface of each of the insulating hard substrates 2a, 2b, 2c, 2d.

The via hole 6a is an insulating hard substrate.
2a and the adhesive layer 4a are formed to penetrate in the thickness direction,
The via hole 6b includes the insulating substrates 2b and 2c and the adhesive layers 4b and 4c.
Is formed so as to penetrate through in the thickness direction, and the via hole 6d
Is formed so as to penetrate through the insulating substrate 2d and the adhesive layer 4d in the thickness direction, and is filled with the conductive paste 5. Of these via holes, 6a is a blind via hole that electrically connects between the conductor circuit 3a as the surface wiring pattern and 3b as the inner layer wiring pattern,
The via hole 6b is a conductor circuit 3b as an inner layer wiring pattern.
And 3c are belly via holes that electrically connect between them, and via holes 6d are blind via holes that electrically connect between the conductor circuit 3c as the inner layer wiring pattern and the conductor circuit 3d as the surface wiring pattern. And both form interstitial via holes.

Examples of the insulating hard substrates 2a, 2b, 2c and 2d include glass cloth epoxy resin, glass nonwoven cloth epoxy resin, glass cloth bismaleimide triazine resin,
A substrate obtained by curing an aramid nonwoven fabric epoxy resin or the like into a plate shape can be used.

The adhesive layers 4a, 4b, 4c and 4d are as follows.
For example, it can be composed of an epoxy-based, polyimide-based, bismaleimidetriazine-based, acrylate-based, or phenol-based resin adhesive.

As the above-mentioned conductive paste, for example,
A conductive paste of copper, silver, gold, carbon, or the like can be used.

The multilayer printed wiring board of the present invention can be mounted with various electronic parts. For example, as shown by a chain double-dashed line in FIG. 2, a chip part 8 such as an IC package or a bare chip is provided with a surface wiring pattern 3a. It can be mounted on a predetermined part of and fixed by solder 9.

Next, a method of manufacturing the multilayer printed wiring board according to the embodiment of the present invention shown in FIG. 2 will be described. (1) First, the single-sided circuit board 7a (17a) of the present invention, which constitutes the multilayer printed wiring board 1 of FIG. 2, is manufactured. This will be specifically described below with reference to FIG. . An insulating rigid substrate 12a having a metal foil 13 as shown in FIG. 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. . Next, the metal foil 13 is etched and processed into a predetermined pattern as shown in FIG. Thus, the conductor circuit 13a is formed. As an etching method, a known general means can be adopted. The conductor circuit 13a is arranged as a surface wiring pattern. However, when the conductor circuit is an inner layer wiring pattern, the surface of the conductor circuit is, for example, microetched or It is advantageous to roughen the surface using a known means such as roughening plating or applying a double-sided roughened copper foil. . Next, as shown in FIG. 3C, an adhesive layer 14a is formed 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. 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 for pre-curing, or laminating an adhesive sheet. At this time, the thickness of the adhesive layer is advantageously in the range of 10 to 50 μm. . Next, as shown in FIG. 3D, a hole 16 that penetrates the adhesive layer 14a and the insulating hard substrate 12a in the thickness direction and contacts 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 beam machine, a hole having a small diameter of 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. According to such a hole forming method of irradiating a laser, it is possible to form a hole only in the adhesive layer 14a and the insulating hard substrate 12a without damaging the conductor circuit 13a. The hole 16 is opened only on the adhesive layer 14a side,
The other end is closed by a conductor circuit. As a result, the via hole and the conductive circuit 13a can be electrically connected reliably. It should be noted that desmearing treatment may be performed for the purpose of cleaning the conductor circuit surface 18 at the bottom of the hole 16. . Next, as shown in FIG. 3 (e), the hole 16 is filled with the conductive paste 5 to form a single-sided circuit board 17a. As a method for filling the conductive paste 5, 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 punching them together during the punching process. Further, it is advantageous to fill the conductive paste to the extent that it slightly protrudes from the hole 16 in order to realize a via hole having good connectivity with a conductor circuit which is an inner layer of another circuit board to be stacked. . In addition, it is advantageous to pre-cure the filled conductive paste in order to enhance the workability of the subsequent steps, and the protective mask is peeled off before stacking.

(2) Insulating hard substrates 12b, 1
For 2c and 12d, a conductor circuit 13 is provided on one surface of this substrate.
b, 13c, 13d, and adhesive layer 14 on the other side
b, 14c, 14d are formed respectively, and the substrate and the adhesive layer are provided with holes 16 penetrating these layers and in contact with the conductors to form via holes filled with the conductive paste 5. A single-sided circuit board 17b as shown in FIG.
17c and 17d are produced.

(3) Next, the above-mentioned single-sided circuit boards 17a, 17
b, 17c, and 17d are superposed in a predetermined order while aligning them using guide holes and guide pins provided around the single-sided circuit board. Here, the conductor circuit 13c of the single-sided circuit board 17c is provided above the adhesive layer 14d of the single-sided circuit board 17d.
And a single-sided circuit board on the adhesive layer 14c.
The adhesive layer 14b of 17b is overlaid, and the conductor circuit
The adhesive layer 14a of the single-sided circuit board 17a is overlaid on the upper side of 13b.

(4) After stacking the single-sided circuit boards in this manner, each single-sided circuit board is press-molded once by heating and pressing in a temperature range of 140 ° C. to 200 ° C. using a hot press. Are integrated in multiple layers. It is advantageous to use a vacuum hot press as the hot press. In this step, the single-sided circuit boards 17a, 17b, 17 stacked on each other with the adhesive layers 14a, 14b, 14c, 14d interposed therebetween.
The adhesive layers 14a, 14b, 14c, and 14d are adhered to each other and c and 17d are adhered to each other and thermally cured, so that they are integrated into a multilayer structure. At the same time, the conductive paste is also brought into close contact with the corresponding conductor circuits and heat-cured to form via holes, whereby the multilayer printed wiring board 1 is obtained.

[Other Embodiments] (1) In the above embodiments, a multilayer printed wiring board in which four layers of single-sided circuit boards are superposed has been described, but the same applies to the case of three or five or more layers. The present invention can be carried out, and a single-sided printed circuit board of the present invention is laminated on 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 produced by a conventional method to manufacture a multilayer printed wiring board. You can (2) In the above-described embodiment, the drilling for forming the via hole is performed by means of laser irradiation. However, mechanical means such as drilling and punching may be applied. A method for manufacturing the single-sided circuit board and the multilayer printed wiring board in this case will be described below with reference to FIGS. 5 and 6. . First, as shown in FIG. 5A, a conductor circuit 23 is formed on an insulating hard substrate 22 by etching a metal foil attached to one surface of the substrate, and a conductor circuit 23 is formed on the opposite side of the conductor circuit 23. An adhesive layer 24 is formed on the surface of the substrate. . Next, a through hole 25 as shown in FIG. 5 (b) is formed by mechanical means such as drilling or punching, and the through hole 25 is filled with the conductive paste 5 to form a single-sided circuit board. To do. At this time, the conductive paste 5 slightly protrudes from the through hole 25 as shown in FIG. 5C in order to realize a via hole having good connectivity with the conductor circuit of another circuit board to be connected. Filling to the extent is advantageous. . Then, in the same manner as in the above embodiment, a plurality of single-sided circuit boards are superposed and integrated to obtain a multilayer printed wiring board 21 having via holes 26 as shown in FIG. (3) In the multilayer printed wiring board of the present invention, the surface wiring pattern may be formed only in a pad shape for mounting chip electronic components.

[0034]

As described above, since the single-sided circuit board for a multilayer printed wiring board according to the present invention is subjected to a predetermined process and has an adhesive layer, it is possible to use this single-sided circuit board. The high-density multilayer printed wiring board having the IVH structure can be efficiently produced with a high yield by integrating the layers in a multilayer structure by a single press molding. That is, according to the method for manufacturing a multilayer printed wiring board according to the present invention using the above-mentioned single-sided circuit board, only the single-sided circuit board having no defect is bonded by the adhesive layer included in the board, which is the case in the prior art. Efficient IV with high yield without using complicated manufacturing method with many repeated steps
It is possible to manufacture a high-density multilayer printed wiring board having an H structure. Further, since the multilayer printed wiring board of the present invention composed of the above single-sided circuit board has a structure in which the single-sided circuit boards are joined by an adhesive layer, it has been conventionally used as a high-density multilayer printed wiring board having an IVH structure. It can be easily provided without a complicated manufacturing method having many repetitive steps such as a technique.

[Brief description of 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 the multilayer printed wiring board according to the present invention.

FIG. 3 is a longitudinal sectional view showing an example of a manufacturing process of a single-sided circuit board used for manufacturing the multilayer printed wiring board.

FIG. 4 is a longitudinal sectional view showing an example of a step of assembling a single-sided circuit board when manufacturing the multilayer printed wiring board.

FIG. 5 is a vertical cross-sectional partial view showing another embodiment of the manufacturing process of the single-sided circuit board used for manufacturing the multilayer printed wiring board.

FIG. 6 is a partial vertical sectional view showing another embodiment of the multilayer printed wiring board according to the present invention.

[Explanation of symbols]

 1 Multilayer printed wiring board 2a, 2b, 2c, 2d Insulating hard board 3a, 3b, 3c, 3d Conductor circuit 4a, 4b, 4c, 4d Adhesive layer 5 Conductive paste 6a, 6b, 6d Via hole 7a, 7b, 7c, 7d Single-sided circuit board 8 Chip component 9 Solder 12a, 12b, 12c, 12d Insulating hard board 13 Metal foil 13a, 13b, 13c, 13d Conductor circuit 14a, 14b, 14c, 14d Adhesive layer 16 Hole 17a, 17b, 17c, 17d Single-sided circuit board 18 Conductor circuit surface at the bottom of the hole 21 Multilayer printed wiring board in another embodiment 22 Insulating substrate in another embodiment 23 Conductor circuit in another embodiment 24 Adhesive layer in another embodiment 25 Through hole in another embodiment 26 Via hole in another embodiment

Claims (5)

[Claims] 1. An insulating hard substrate, wherein 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 are formed. A single-sided circuit board for a multilayer printed wiring board, characterized in that a via hole filled with a conductive paste is formed by forming a hole penetrating these layers and contacting a conductor. 2. The single-sided circuit board for a multilayer printed wiring board according to claim 1, wherein the conductor circuit is formed by etching a copper foil of a single-sided copper-clad laminate. 3. 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 layer of the circuit board is an insulating hard board. A conductor circuit is formed on one surface of the substrate, and an adhesive layer is formed on the other surface, and holes are formed in the substrate and the adhesive layer so as to pass through these layers and contact the conductor. A multilayer printed wiring board comprising a single-sided circuit board provided with a via hole filled with a conductive paste. 4. 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; A step of 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; Stacking two or more of the above single-sided circuit boards or stacking them together with another circuit board, and then using the adhesive layer of the boards to integrate them into a multilayer by a single press molding, A method for manufacturing a multilayer printed wiring board, characterized in that 5. The method for manufacturing a multilayer printed wiring board according to claim 3, wherein the hole penetrating the insulating hard substrate and the adhesive layer and contacting the conductor is formed by laser irradiation.