JP2587593B2 - Printed wiring board and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board used for electronic equipment and a method for manufacturing the printed wiring board.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and high-density of electronic devices, multilayer printed wiring boards have been strongly demanded not only for industrial use but also for consumer use. In such a multilayer printed wiring board, a method of connecting inner via holes between a plurality of wiring patterns and a highly reliable structure are required.

Hereinafter, a conventional method for manufacturing a double-sided printed wiring board will be described. 8 (a) to 8 (e) are process sectional views showing a conventional method for manufacturing a double-sided printed wiring board. First, as shown in FIG. 8A, an insulating substrate 801 such as a glass epoxy substrate is prepared. Next, as shown in FIG. 8B, a copper foil 802 is overlaid on both surfaces of the insulating substrate 801. Next, the insulating substrate 801 and the copper foil 802 are bonded by heating and pressing. Next, as shown in FIG.
02, a first wiring pattern 805 and a second wiring pattern 806 are formed by an existing technique such as etching. Next, as shown in FIG. 8D, through holes 803 are formed by drilling at locations where the first wiring pattern 805 and the second wiring pattern 806 are to be electrically connected.
Next, as shown in FIG. 8E, a conductive paste 804 is printed and filled in the through holes 803, and the conductive paste is cured.

In this manner, the first wiring pattern 80
5 and the second wiring pattern 806 are connected by the conductive paste 804 filled in the through holes 803, and a double-sided printed wiring board 807 is obtained.

[0005]

However, in the above-described conventional structure, the adhesion between the conductive paste and the wall surface of the through hole is poor, and there is a difference in the thermal expansion coefficient between the conductive paste and the insulating substrate. There has been a problem that destruction occurs at the interface between the conductive paste and the through-hole due to thermal shock at the time of solder reflow or the like, causing conduction failure.

In order to solve the above-mentioned conventional problems, the present invention improves the adhesion between the conductive resin composition and the wall surface of the through hole of the substrate, and provides a highly reliable printed wiring board and a method of manufacturing the same. The purpose is to:

[0007]

According to a first aspect of the present invention, there is provided a printed wiring board having a through hole formed in a thickness direction of a resin-impregnated fiber sheet substrate. a printed wiring board conductive resin composition for the electrical connection in the thickness direction of the is filled, before
The resin impregnated fiber sheet substrate material has pores with a closed structure inside.
Wherein the substrate and the conductive resin composition are a conductive resin
The composition is formed from a plurality of pores of a closed structure in a substrate.
With a structure that protrudes into the substrate with the recess filled
Characterized in that it is integrated Ri.

Next, a second printed wiring board of the present invention
Has a through hole in the thickness direction of the resin-impregnated fiber sheet substrate.
The through hole has an electrical connection in the thickness direction of the substrate.
Printed with conductive resin composition for printing
A wiring board, the conductive resins composition, metal particles
And a resin, and the size of the metal fine particles
Has an average particle diameter in the range of 0.2 to 20 μm.
The resin which is one component of the conductive resin composition is contained in the substrate.
The substrate and the conductive resin composition are integrated by the structure penetrating into
It is characterized by having been made.

Next, a third printed wiring board of the present invention
Has a through hole in the thickness direction of the resin-impregnated fiber sheet substrate.
The through hole has an electrical connection in the thickness direction of the substrate.
Printed with conductive resin composition for printing
A wiring board, wherein the conductive resin composition contains metal fine particles.
And a resin, and the size of the metal fine particles
Has an average particle diameter in the range of 0.2 to 20 μm.
A resin as one component of the conductive resin composition, and a substrate
Is self-adhesive due to covalent bonding with
The substrate and the conductive resin composition are integrated
It is characterized by.

Next, the fourth printed wiring board of the present invention
Has a through hole in the thickness direction of the resin-impregnated fiber sheet substrate.
The through hole has an electrical connection in the thickness direction of the substrate.
Printed with conductive resin composition for printing
A wiring board, wherein the substrate is placed in the conductive resin composition.
The structure of the heat-resistant synthetic fiber that makes up
Characterized in that it is integrated with the conductive resin composition.
You. Further, in the above configuration, it is preferable that both the impregnated resin of the substrate and the resin that is one component of the conductive resin composition are thermosetting resins.

In the above structure, the thermosetting resin is preferably at least one selected from an epoxy resin, a thermosetting polybutadiene resin, a phenol resin and a polyimide resin.

In the above structure, it is preferable that the resin-impregnated fiber sheet of the substrate uses at least one selected from heat-resistant synthetic fibers and glass fibers. Further, in the above configuration, it is preferable that the heat-resistant synthetic fiber uses at least one selected from an aromatic polyamide fiber and a polyimide fiber.

In the above structure, the resin-impregnated fiber sheet of the substrate is preferably a nonwoven fabric. Further, in the above configuration, the metal fine particles in the conductive resin composition,
It is preferably at least one selected from gold, silver, copper, palladium, nickel and alloys thereof.

In the above structure, it is preferable that the amount of the fine metal particles in the conductive resin composition is in the range of 80 to 92.5% by weight. Further, in the above configuration, the size of the metal fine particles in the conductive resin composition is preferably in the range of an average particle diameter of 0.2 to 20 μm.

In the above structure, the size of the through-hole filled with the conductive resin composition has an average diameter of 50 to 30.
It is preferably in the range of 0 μm. In the above configuration, it is preferable that a circuit is formed on the surface of the substrate and at the end of the conductive resin composition.

In the above structure, it is preferable that the number of substrates is one or more.

[0017] The first method for manufacturing a printed wiring board of the present invention then, both surfaces are not covered with a cover film, and the thickness direction of the uncured resin-impregnated fiber sheet substrate material having an internal voids, Forming a through hole by laser light irradiation, filling the through hole with a conductive paste, then removing the cover film, bonding a metal foil to at least one side of the substrate material, and then heating the substrate material The method is characterized in that the substrate material and the conductive paste are integrated by pressing and compression-hardening, and thereafter, the metal foil is patterned into a predetermined shape. In the above description, the term “uncured” of the resin of the substrate material includes a semi-cured resin.
In the above configuration, it is preferable to bond metal foil to both surfaces of the substrate material.

[0018] Next the method of the printed wiring board the second manufacturing the present invention, not covered on both sides with a cover film, and the thickness direction of the uncured resin-impregnated fiber sheet substrate material having an internal voids, laser Forming a through hole by light irradiation, filling the through hole with a conductive paste, then removing the cover film and preparing two intermediate bodies in which a metal foil is bonded to one surface of the substrate material, The intermediate metal foil is placed so that the surface of the metal foil is on the outside, a circuit board having at least two layers of wiring patterns in the center is sandwiched, and the whole is heated and pressurized to be compressed and hardened, so that the substrate material and the conductive material are electrically conductive. A method of manufacturing a multilayer printed wiring board, wherein a conductive paste is integrated, and thereafter, the metal foil on the surface is patterned into a predetermined shape.

The third method of manufacturing the printed wiring board of the present invention then have covered on both sides with a cover film, and the thickness direction of the uncured resin-impregnated fiber sheet substrate material having an internal voids, laser Forming a through-hole by light irradiation, filling the through-hole with a conductive paste, then removing the cover film to create an intermediate connector, between the plurality of double-sided printed wiring boards, respectively, the intermediate connector This is a method for manufacturing a multilayer printed wiring board in which the substrate material and the conductive paste are integrated by holding, compressing and hardening the whole by heating and pressing.

In the above structure, it is preferable that the holes inside the uncured resin impregnated fiber sheet substrate material are holes having a closed structure. Further, in the above configuration, the pore diameter of the uncured substrate material having the pores of the closed structure is 5 to 20 μm.
m is preferable.

In the above structure, it is preferable that the porosity of the uncured substrate material having pores is 2 to 35%. Further, in the above configuration, the heating temperature of the substrate material is preferably in a range of 170 to 260 ° C.

In the above structure, the pressure applied to the substrate material is preferably in the range of ²⁰ to 80 kg / cm ² . Further, in the above configuration, it is preferable that a part of the fiber in the substrate material is left in the through hole by irradiating the laser beam.

Further, in the above-described structure, a composition of fine metal particles and a resin is used as the conductive resin composition, and when the conductive resin composition is filled in the through-hole, one component of the conductive resin composition is used. It is preferable that a certain resin is permeated into the substrate to be integrated.

In the above structure, the resin, which is a component of the conductive resin composition, and the impregnated resin of the substrate are made of substantially the same resin, and are integrated by self-adhesion through covalent bonding. preferable.

In the above construction, both the impregnated resin of the substrate and the resin which is a component of the conductive resin composition are thermosetting resins, and are made of epoxy resin, thermosetting polybutadiene resin, phenol resin and polyimide resin. It is preferable that at least one is selected.

In the above structure, the method of filling the conductive resin composition into the through holes is preferably a roll coating method. In the above configuration, it is preferable that the resin-impregnated fiber sheet of the substrate uses at least one selected from heat-resistant synthetic fibers and glass fibers.

In the above structure, it is preferable that the heat-resistant synthetic fiber uses at least one selected from an aromatic polyamide fiber and a polyimide fiber. Further, in the above configuration, it is preferable that the resin-impregnated fiber sheet of the substrate is a nonwoven fabric.

In the above structure, the metal fine particles in the conductive resin composition are preferably at least one selected from gold, silver, copper, palladium, nickel and alloys thereof.

In the above structure, it is preferable that the amount of the fine metal particles in the conductive resin composition is in the range of 80 to 92.5% by weight. Further, in the above configuration, the size of the metal fine particles in the conductive resin composition is preferably in the range of an average particle diameter of 0.2 to 20 μm.

In the above structure, the size of the through-hole filled with the conductive resin composition has an average diameter of 50 to 30.
It is preferably in the range of 0 μm. In the above configuration, it is preferable that the laser beam is at least one selected from a carbon dioxide laser, a YAG laser, and an excimer laser.

[0031]

According to the configuration of the first printed wiring board of the present invention described above, the resin-impregnated fiber sheet substrate material has a dense inside.
Having a closed structure pores, the substrate and the conductive resin composition
Indicates that the conductive resin composition is formed from pores with a closed structure in the substrate.
Projecting into the substrate with the plurality of recesses
By being integrated by the structure that came out , the adhesion between the conductive resin composition and the wall surface of the through hole of the substrate is improved,
A highly reliable printed wiring board can be realized. Further, by the structure where the conductive resin composition protrudes into the substrate, the anchor effect increases, adhesion of the conductive paste and the wall surface of the through-hole is improved.

Next, the second printed wiring board of the present invention
According to the configuration, the conductive resin composition comprises metal fine particles.
A composition with a resin, and the size of the metal fine particles
Has an average particle diameter in the range of 0.2 to 20 μm.
The resin which is one component of the conductive resin composition is contained in the substrate.
The substrate and the conductive resin composition are integrated by the structure penetrating into
Because it is of, after which it is strong integration of the substrate and the conductive resin composition, the concentration of the conductive component of the conductive resin composition is increased, realizing high conduction reliability printed wiring board it can.

Next, the third printed wiring board of the present invention
According to the configuration, in the thickness direction of the resin-impregnated fiber sheet substrate,
A through-hole is formed, and the through-hole has an electric current in the thickness direction of the substrate.
Filled with a conductive resin composition for pneumatic connection
Printed wiring board, wherein the conductive resin composition,
A composition of metal fine particles and a resin, and wherein the metal fine particles
In the range of the average particle diameter of 0.2 to 20 μm,
And a tree which is a component of the conductive resin composition.
Resin and the impregnating resin of the substrate are covalently bonded and self-adhered.
By doing so, the substrate and the conductive resin composition are integrated
By doing so , stronger integration can be achieved .

Next, the fourth printed wiring board of the present invention will be described.
According to the configuration, in the thickness direction of the resin-impregnated fiber sheet substrate,
A through-hole is formed, and the through-hole has an electric current in the thickness direction of the substrate.
Filled with a conductive resin composition for pneumatic connection
Printed wiring board, wherein the conductive resin composition contains
The structure in which the heat-resistant synthetic fibers constituting the substrate protrude
Substrate and the conductive resin composition are integrated
Thus, the bonding area around the fiber is improved, and the substrate and the conductive resin composition can be strongly integrated.

As a preferred example of the above configuration, when both the impregnated resin of the substrate and the resin which is one component of the conductive resin composition are thermosetting resins, the heat resistance is excellent.

Further, as a preferable example of the above configuration, the thermosetting resin is an epoxy resin, a thermosetting polybutadiene resin,
If it is at least one selected from a phenolic resin and a polyimide resin, it will be excellent in practicality from the viewpoint of heat resistance.

Further, as a preferable example of the above configuration, when the resin-impregnated fiber sheet of the substrate is made of at least one selected from heat-resistant synthetic fibers and glass fibers, the heat resistance is excellent.

As a preferable example of the above-mentioned structure, when the heat-resistant synthetic fiber is made of at least one selected from an aromatic polyamide fiber and a polyimide fiber, the heat resistance is excellent and the heat-resistant synthetic fiber is penetrated by using a laser beam. Easy to drill holes.

Further, as a preferred example of the above configuration, when the resin-impregnated fiber sheet of the substrate is a non-woven fabric, the thickness of the substrate can be easily controlled and the cost can be reduced. The thickness of the substrate may vary depending on the application, but is preferably in the range of about 30 to 500 μm.

Further, as a preferred example of the above structure, when the metal fine particles in the conductive resin composition are at least one selected from gold, silver, copper, palladium, nickel and alloys thereof, the electric conductivity is improved. Can hold.

Further, as a preferable example of the above configuration, it is practical if the amount of the metal fine particles in the conductive resin composition is in the range of 80 to 92.5% by weight. Further, as a preferable example of the configuration, when the size of the metal fine particles in the conductive resin composition is in the range of an average particle diameter of 0.2 to 20 μm, the paste (paint) becomes stable.

As a preferred example of the above configuration, the size of the through-hole filled with the conductive resin composition has an average diameter of 50%.
When it is in the range of ~ 300 µm, high electrical conductivity can be maintained. Further, as a preferable example of the above configuration, when a circuit is formed on the surface of the substrate and at the end of the conductive resin composition, a circuit substrate using a single-phase or multilayer substrate can be easily realized. In the case of a multilayer substrate, the substrates can be appropriately combined according to the purpose.

Next, according to the structure of the first method for manufacturing a printed wiring board of the present invention, an uncured resin impregnated fiber sheet substrate having both sides covered with a cover film and having pores therein. In the thickness direction of the material, a through hole is formed by irradiating a laser beam, filling the through hole with a conductive paste, then removing the cover film and attaching a metal foil to at least one surface of the substrate material, Next, the substrate material is heated and pressurized and compression-cured to integrate the substrate material and the conductive paste, and then, by patterning the metal foil into a predetermined shape, efficiently and reasonably. Can be manufactured. In particular, since the through-hole is formed by irradiating a laser beam, precision fine processing is possible, and unlike the conventional drilling, no cutting chips are generated and a clean manufacturing environment can be maintained.

Next, the second embodiment of the printed wiring board of the present invention will be described.
According to the manufacturing method, not covered on both sides with a cover film, and the thickness direction of the uncured resin-impregnated fiber sheet substrate material having an internal pore, a through hole is formed by laser beam irradiation,
The through-hole is filled with a conductive paste, and then the cover film is removed to prepare two intermediate bodies each having a metal foil attached to one surface of the substrate material. And a circuit board having a wiring pattern of at least two layers in the center is sandwiched, and the substrate material and the conductive paste are integrated by heating and pressurizing and compressing and curing the whole, and thereafter, By patterning the metal foil on the surface into a predetermined shape,
Printed wiring boards can be efficiently and rationally manufactured. As a preferable example of the above configuration, when metal foils are attached to both surfaces of the substrate material, it can be effectively used as a single-layer substrate or as a component of a multilayer substrate.

Next, the third printed circuit board of the present invention
According to the manufacturing method, not covered on both sides with a cover film, and the thickness direction of the uncured resin-impregnated fiber sheet substrate material having an internal pore, a through hole is formed by laser beam irradiation,
Filling the through-holes with conductive paste, then removing the cover film to create an intermediate connector, sandwiching the intermediate connector between a plurality of double-sided printed wiring boards, respectively, and heating and pressing the whole. By integrating the substrate material and the conductive paste by compression curing ,
A layer printed wiring board can be efficiently and rationally manufactured.

Further, as a preferred example of the above structure, if the pores inside the uncured resin impregnated fiber sheet substrate material are pores having a closed structure, even if the density of the through holes is high, the pores of the adjacent through holes may be high. Short circuits can be effectively prevented without mixing with the conductive paste. Further, in the above configuration, as a preferred example, when the pore diameter of the uncured substrate material having the pores of the closed structure is 5 to 20 μm, the conductive resin composition has a structure protruding into the substrate, and the conductive paste It is practical because the anchor effect can be exhibited.

Further, as a preferable example of the above-mentioned structure, when the porosity of the uncured substrate material having pores is 2 to 35%, the anchor effect of the conductive paste can be further exhibited, and it is practical.

Further, as a preferable example of the above configuration, when the heating temperature of the substrate material is in the range of 170 to 260 ° C., the curing reaction can be effectively completed when a thermosetting resin is used.
Further, as a preferable example of the above configuration, the pressing force of the substrate material is 2
When it is in the range of 0 to 80 kg / cm ² , air holes in the substrate can be substantially eliminated, and the characteristics of the substrate can be effectively exhibited.

Further, as a preferred example of the above-described structure, when a part of the fibers in the substrate material is left in the through-hole by irradiating a laser beam, strong adhesion between the conductive paste and the substrate material can be achieved.

Further, as a preferable example of the above configuration, a composition of fine metal particles and a resin is used as the conductive resin composition,
Also, when filling the through-hole with the conductive resin composition, the resin, which is a component of the conductive resin composition, is allowed to penetrate into the substrate and be integrated, resulting in strong integration between the conductive paste and the substrate material. Is peeled off.

As a preferred example of the above structure, a resin which is one component of the conductive resin composition and the impregnated resin of the substrate are made of substantially the same resin and are integrated by self-adhesion by covalent bond. Thus, strong adhesion between the substrate and the conductive paste can be achieved. Further, in the above-described configuration, as a preferred example, both the impregnated resin for the substrate and the resin that is a component of the conductive resin composition are thermosetting resins, and the epoxy resin, the thermosetting polybutadiene resin, the phenol resin, and the polyimide resin are used. If at least one is chosen,
Strong adhesion between the substrate and the conductive paste can be achieved, and heat resistance is excellent.

Further, as a preferred example of the above structure, when the method of filling the conductive resin composition into the through-holes is a roll coating method, it can be simply applied by applying a conductive paste on a cover film (release film). Can be filled.

Further, according to a preferred configuration in which the laser light having the above-mentioned configuration is at least one selected from a carbon dioxide laser, a YAG laser and an excimer laser, the perforation can be efficiently performed.

As described above, the through holes provided in the uncured substrate material having the holes having the closed structure and the holes existing in the substrate material from the inner walls of the through holes are electrically connected to the concave portions opened when the through holes are formed. By filling the conductive paste, the anchor effect is increased, and the adhesion between the conductive paste and the wall surface of the through hole is improved. Further, since the wiring pattern is arranged on the through hole filled with the conductive paste, the contact area between the conductive paste and the metal foil is increased. As a result, a printed wiring board having excellent thermal shock resistance can be realized.

[0055]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a printed wiring board according to an embodiment of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a sectional view of a circuit board according to an embodiment of the present invention. 2 (a) to 2 (e) are process cross-sectional views showing a process for manufacturing a circuit board. First, as shown in FIG. 1, the circuit board according to the present embodiment is obtained by compressing a porous base material impregnated with a thermosetting resin by heating and pressing, and curing the insulating substrate 101 by heating and pressing. A circuit pattern 102 formed by patterning a metal foil adhered on a base material by etching, and a conductive paste 103 filled in a through hole provided in a porous base material.
And a portion 103a of the binder resin in the conductive paste 103 that has penetrated into the porous base material.

As shown in FIG. 2 (a), the method for manufacturing a circuit board described above comprises a protective film 201 such as polyethylene terephthalate having a thickness of 12 μm on both sides, and a thickness of 180 μm.
m porous substrate 202 was prepared. This porous substrate 20
Reference numeral 2 denotes a substrate having pores 202a therein, for example, an aromatic polyamide (aramid) fiber (for example, “Kevlar” manufactured by DuPont, fineness: 1.5 denier, length: 7 m)
m, a basis weight: 70 g / m ² ), and a base material (hereinafter referred to as an aramid-epoxy sheet) made of a composite material impregnated with a thermosetting epoxy resin (for example, “EPON1151B60” manufactured by Shell) into a nonwoven fabric. . Here, the volume ratio of the holes 202a to the aramid-epoxy sheet 202 is 40%.
It is.

Next, as shown in FIG. 2B, a through hole 203 having a diameter of 200 μm was formed in a predetermined portion of the aramid-epoxy sheet 202 by, for example, a laser processing method using a carbon dioxide gas laser or the like.

Next, as shown in FIG.
Was filled with a conductive paste 204. Here, the conductive paste 204 is made of a copper powder having an average particle diameter of 2 μm as a conductive substance, and a non-solvent type epoxy resin as a binder resin. The copper powder content is 85% by weight, and the copper powder and the binder resin are mixed. It was produced by kneading with this roll. As a method of filling the conductive paste 204, the aramid-epoxy sheet 22 having the through holes 203 was placed on a table of a printing machine (not shown), and the conductive paste 204 was printed directly on the protective film 201. . As a printing method, for example, roll transfer printing can be used. At this time, the upper protective film 2
Reference numeral 01 plays a role of a print mask and a role of preventing contamination of the surface of the aramid-epoxy sheet 202. At this stage, a portion 204a of the binder resin of the conductive paste 204 has already penetrated into the aramid-epoxy sheet 202 side, and inside the conductive paste 204, the composition ratio of the conductive material to the binder resin gradually increases (FIG. 2 (d)
). Next, the protective film 201 was peeled off from both surfaces of the aramid-epoxy sheet 202.

Next, as shown in FIG. 2E, a metal foil 205 is formed on both sides of the aramid-epoxy sheet 202 to a thickness of 35 mm.
A μm copper foil was attached. By heating and pressing in this state, the aramid-epoxy sheet 202 was compressed and the aramid-epoxy sheet 202 and the metal foil 205 were bonded as shown in FIG. 2 (f). The heating and pressurizing conditions were as follows: the temperature was raised from room temperature to 200 ° C. in 30 minutes while applying a pressure of 60 kgf / cm ² in vacuum, kept at 200 ° C. for 60 minutes, and then lowered to room temperature in 30 minutes. In this step, the conductive paste is also compressed, but at that time, the binder component is extruded from between the conductive materials, and the bonding between the conductive materials and between the conductive material and the metal foil is strengthened. The substance was densified, and at the same time, the epoxy resin as one component of the aramid-epoxy sheet 22, the conductive paste 204, and the binder component 204 a of the conductive paste 204 permeated into the aramid-epoxy sheet 2 were cured. At this time, the conductive paste 204
The content of the conductive material therein rose to 92.5 wt%. Further, by applying heat and pressure, the pores 20 in the porous base material 202 are formed.
2a was 0 to 1 vol.%, And the shape of the hole 202a was also reduced.

Finally, as shown in FIG.
5 was formed into a circuit pattern 205a by ordinary etching. The circuit board 206 was able to be manufactured by the above method.

The phenomenon that the binder component in the conductive paste 204 penetrates into the porous substrate 202 is caused by partially replacing the binder in the conductive paste 204 with a dye.
02 was confirmed by filling the through-hole 203.
As the binder component 204a in the conductive paste 204 that has penetrated into the porous base material 202 is cured, the interface between the conductive paste 204 and the porous base material 202 is firmly bonded. Further, the binder component in the conductive paste 204 is selected from those having the same component as the thermosetting resin in the porous substrate 202 or those having a property of reacting with the thermosetting resin in the porous substrate 202 and curing. Then, a chemical bond was generated between the protrusion of the binder resin and the thermosetting resin in the porous substrate, and the anchor effect of the protrusion of the binder resin was further increased.

Embodiment 2 Next, a method of manufacturing a multilayer circuit board according to an embodiment of the present invention will be described with reference to the drawings.

FIGS. 3A to 3H are sectional views showing the steps of manufacturing a multilayer circuit board according to one embodiment of the present invention.
(a) and (e) are first and second metal foils, (b) and (d) are first and second intermediate connectors, (c) is a circuit board, and (f) to
(h), a first intermediate connector and a second intermediate connector are arranged above and below a circuit board, and a first metal foil and a second metal foil are arranged above and below the circuit board and laminated. And a step of forming a circuit on the second metal foil to form a multilayer circuit board.

First, FIG. 2A to FIG.
(g) The circuit board 303 (circuit board 206
(Substantially the same as FIG. 3 (c)), and then manufactured separately from the circuit board 303 in the steps shown in FIGS. 2 (a) to 2 (d), and further the first protective film is peeled off. Intermediate connector 301
(FIG. 3B) and a second intermediate connector 302 (FIG.
(d)) were prepared respectively. Further, 304 in FIG. 3A and 305 in FIG. 3E are metal foils (copper foils).

As shown in FIG. 3 (f), a first intermediate connector 301 and a second intermediate connector 302 are aligned above and below a circuit board 303, and a first metal is arranged above and below it. The foil 304 and the second metal foil 305 were overlaid. Next, as shown in FIG. 3 (g), the circuit board 303 and the metal foils 304 and 305 are heated and pressed to remove
Adhered through Nos. 1 and 302. The metal foils 304 and 305 were each etched by an ordinary pattern forming method to form a circuit pattern. Thus, a four-layered multilayer circuit board 306 was obtained. To further increase the number of layers, the circuit board 303 shown in FIG.
6 by repeating the steps shown in FIGS. 3 (a) to 3 (h).

As another multi-layering method, a multi-layer circuit board can be manufactured by sandwiching an intermediate connector between two or more circuit boards and applying heat and pressure.

(Embodiment 3) FIGS. 4A to 4F are sectional views showing the steps of a method for manufacturing a printed wiring board according to another embodiment of the present invention. 4, reference numeral 401 denotes a porous substrate, 402 denotes a release film, and 403 denotes a release film.
Is an uncured substrate material having pores of a closed structure, 404 is a pore, 405 is a through hole, 406 is a recess, 407 is a conductive paste, 408 is a metal foil, 408 is an insulating layer, and 410 is a wiring pattern. . In this embodiment, the porous substrate 401
In order to control the pore diameter and the porosity in the substrate by utilizing the compressibility of the substrate, the porous substrate 401 shown in FIG. Preferably, a composite material of an aromatic polyamide and an epoxy resin in which a non-woven fabric is impregnated with a thermosetting resin is used. FIG.
4B shows that the porous base material 401 shown in FIG. 4A is preheated and pressed to compress the porous base material 401 at a constant rate in the thickness direction, and has pores of a closed structure with a controlled pore diameter and porosity. The state where the uncured substrate material 103 is formed is shown. FIG.
FIG. 4C shows a state in which a through-hole 405 is provided in the uncured substrate material 403 having pores of the closed structure and the release film 402 of FIG. The holes 4 in the uncured substrate material 403 having the holes of the closed structure when the through holes 405 are formed.
04 is opened, and a plurality of recesses 406 are formed in the inner wall of the through hole 405.
Are formed. The formation of the through hole 405 and the concave portion 406 can be performed by a drill or various laser processings, but in this embodiment, processing by a carbon dioxide laser was optimal.

FIG. 4D shows that the conductive paste 407 is applied through the release film 402 to the through-hole 405 provided in the uncured substrate material 403 having a closed-hole and a plurality of recesses 406 on the inner wall of the through-hole. The figure shows a state where the release film 402 is peeled off after filling. FIG. 4E shows a state in which a metal foil 408 is attached to the upper and lower portions of FIG. 4D and a final heating and pressurizing is performed to cure the thermosetting resin and electrically connect the metal foils with the conductive paste 407. FIG. Uncured substrate material 403 having pores of a closed structure
Is further compressed, the holes 404 in the substrate disappear, and the final insulating layer 409 is formed. However, the plurality of recesses 406 on the inner wall of the through hole do not disappear because the conductive paste 407 has already been filled. As a result, the adhesion between the conductive paste 407 and the wall surface of the through hole 405 is improved due to an increase in the anchor effect, and a printed wiring board having excellent thermal shock resistance can be realized. FIG. 4F shows a metal foil 40 on the surface.
8 shows a state in which a double-sided printed wiring board is manufactured by etching.

Embodiment 4 Next, a method of manufacturing a multilayer printed wiring board according to another embodiment of the present invention will be described with reference to the drawings.

FIGS. 5A to 5H are sectional views showing the steps of a method for manufacturing a multilayer printed wiring board according to an embodiment of the present invention. In FIG. 5, reference numeral 501 denotes a first metal foil, 502 denotes a second metal foil, 503 denotes an uncured substrate material having holes having a closed structure, 504 denotes holes, 505 denotes a conductive paste, and 506 denotes a conductive paste.
Is a second wiring pattern, 507 is a third wiring pattern,
508 is an insulating layer, and 509 and 510 are first layers used for laminating and interconnecting a metal foil and a double-sided printed wiring board.
And a second intermediate connector, 511 is a double-sided printed wiring board, 512 is a first wiring pattern, 513 is a fourth wiring pattern, and 514 is a multilayer printed wiring board having four layers.

FIGS. 5F to 5H show a case where a first intermediate connector 509 and a second intermediate connector 510 are arranged above and below a double-sided printed wiring board 511, and a first metal is arranged above and below it. The steps of arranging and laminating a foil 501 and a second metal foil 502 and forming a circuit on the first metal foil 501 and the second metal foil 502 to form a multilayer printed wiring board are shown. FIG. 4 (a) shows the intermediate connectors 509 and 510.
Uncured substrate material having pores of a closed structure in which a conductive paste was filled in a through hole and a plurality of recesses in the inner wall of the through hole, manufactured in the steps shown in (d) to (d), was used. As shown in FIG. 5 (f), a first intermediate connector 509 and a second intermediate connector 510 are aligned above and below a double-sided printed wiring board 511, and a first metal foil is arranged above and below it. 501 and the second metal foil 502 were overlapped. Next, FIG.
As shown in FIG.
And the first metal foil 501 and the second metal foil 502
Of the first metal foil 501 and the second wiring pattern 506, and the second metal foil 502 and the third wiring pattern 507 are electrically connected to each other via the intermediate connector 509 and the second intermediate connector 510. Connected to. At this time,
The second wiring pattern 506 is the first intermediate connector 509
In addition, the third wiring pattern 507 is
0, resulting in an inner layer structure as shown in FIG. Next, the first metal foil 501 and the second metal foil 5
02 was etched to form a first wiring pattern 512 and a fourth wiring pattern 513, and a four-layer multilayer printed wiring board 514 shown in FIG. 5H was obtained. Further, by replacing the double-sided printed wiring board 511 of FIG. 5 (c) in the steps of FIGS. 5 (a) to 5 (h) with a multilayer printed wiring board, a high multilayer structure can be easily realized.

Embodiment 5 Next, a method for manufacturing a multilayer printed wiring board according to another embodiment of the present invention will be described with reference to the drawings.

FIGS. 6A to 6E are sectional views showing the steps of a method for manufacturing a multilayer printed wiring board according to one embodiment of the present invention. 6, reference numeral 601 denotes a first wiring pattern;
Is a second wiring pattern, 603 is a conductive paste, 60
4 is an insulating layer, 605 is a third wiring pattern, 606 is a fourth wiring pattern, 607 is a hole, 608 is an uncured substrate material having a closed structure hole, and 609 and 610 are the first and second materials. 611 is an intermediate connector used for laminating and interconnecting the first double-sided printed wiring board 609 and the second double-sided printed wiring board 610, and 612 is a four-layer multilayer printed wiring board. . FIG.
(D) and (e) show the first double-sided printed wiring board 609
A step of forming a multilayer printed wiring board by laminating an intermediate connector 611 between the first printed wiring board and the second double-sided printed wiring board 610 is shown. FIG. 4 shows the intermediate connector 611.
An uncured substrate material having pores of a closed structure in which a conductive paste was filled in a through-hole and a plurality of recesses in the inner wall of the through-hole, manufactured in the steps shown in (a) to (d), was used. FIG. 6 (d)
As shown in the figure, the intermediate connector 611 was overlaid on the second double-sided printed wiring board 610, and the first double-sided printed wiring board 611 was overlaid thereon. Next, as shown in FIG.
The first double-sided printed wiring board 609 and the second double-sided printed wiring board 610 are bonded by applying heat and pressure, and the second wiring pattern 602 and the third wiring pattern 605 are electrically connected by the conductive paste 603. Was. At this time, the first wiring pattern 601 and the fourth wiring pattern 606 penetrate the insulating layer 604, and the second wiring pattern 602 and the third wiring pattern 605 bite into the intermediate connector 608, so that the outermost layer is smoothed. The obtained four-layered multilayer printed wiring board 612 was obtained.

Further, in order to manufacture a multilayer printed wiring board having a larger number of laminations, a required number of double-sided printed wiring boards and intermediate connectors for interconnecting them are prepared. After inserting the connecting body, heat and press to laminate at once, or FIG. 6 (a)
Alternatively, it is possible by replacing the double-sided printed wiring board of (b) with a multilayer printed wiring board.

Example 6 In this example, an integrated structure of a substrate material and a conductive resin composition will be described with reference to the drawings. FIG. 7A shows a copper foil 702.
FIG. 7 is a schematic cross-sectional view before a sheet is placed on both sides of a sheet and subjected to compression processing. An aramid-epoxy sheet 701 having a thickness of 200 μm was used as a porous base material, and a polyethylene terephthalate film having a thickness of 12 μm was used as a release film provided on both sides thereof. This was heated at a press temperature of 100 ° C. and a pressure of 30 kg / cm ² using a hot press.
The substrate was preheated and pressurized for one minute to form an uncured substrate material having a hole 701a having a closed structure. Using a carbon dioxide gas laser, a through hole 703 having a diameter of 0.2 mm is formed, and a part of an air hole 701a having a closed structure (the inner wall of the through hole).
A plurality of recesses 703a were formed in the substrate. The through-hole 703 and the plurality of recesses 703a on the inner wall of the through-hole were filled with a conductive paste in which silver powder as metal particles was dispersed in a solvent-free epoxy resin. By doing so, the concave portion 703a
By filling the conductive paste with the conductive paste, the anchor effect is increased, and the adhesion between the conductive paste and the wall surface of the through hole is improved.

FIG. 7B shows that the copper foil 702 is
FIG. 10 is a schematic cross-sectional view of another example before being arranged on both surfaces of the sheet and subjected to compression processing. The same porous substrate as described above was used. If the irradiation energy of the carbon dioxide laser is low, the penetration hole 70
Part 3 of the fiber 701b of the sheet remains and protrudes. When the conductive paste is filled in the through holes 703 in this state,
By filling the portion 703b around the constituent fiber 701b with the conductive paste, the anchor effect is increased, and the adhesion between the conductive paste and the wall surface of the through hole is improved.

FIG. 7C shows that the copper foil 702 is
FIG. 10 is a schematic cross-sectional view of another example before being arranged on both surfaces of the sheet and subjected to compression processing. The same porous substrate as described above was used. If the compatibility between the resin component of the conductive paste and the resin component of the base material sheet is good, when the conductive paste is filled into the through holes 703, the resin component of the conductive paste impregnates the base material side and the mixed layer 703c is formed. It is formed. The mixed layer 703c improves the adhesion between the conductive paste and the wall surface of the through-hole, increases the concentration of the conductive component (for example, metal fine particles) of the conductive paste, and improves the conductivity.

Example 7 In this example, an aramid-epoxy sheet having a thickness of 200 μm was used as a porous base material, and a polyethylene terephthalate film having a thickness of 4 to 50 μm was used as a release film provided on both sides thereof. Was. This was heated at a press temperature of 100 ° C. and a pressure of 5 to 50 kg / cm ² using a hot press.
The substrate was preheated and pressurized for minutes to form an uncured substrate material having pores of a closed structure. Using a carbon dioxide laser for this,
A through hole having a diameter of 0.2 mm was formed, and a hole in an uncured substrate material having a closed structure was opened, and a plurality of recesses were formed in the inner wall of the through hole. After filling a conductive paste in which silver powder as metal particles is dispersed in a solvent-free epoxy resin into the plurality of recesses of the through hole and the inner wall of the through hole, the release film is peeled off, and the thickness of both surfaces is reduced to 35 μm.
The copper foil was laminated and heated and pressed at 170 ° C. for 1 hour at a pressure of 30 kg / cm ² using a hot press to form a double-sided copper-clad board. A wiring pattern was formed on the copper foil layer formed by the above-described method using a known etching technique, and a double-sided printed wiring board was manufactured.

FIG. 9 shows the results of a solder reflow test on a printed wiring board obtained by the manufacturing method of this embodiment. The vertical axis in FIG. 9 shows the amount of change in connection resistance per 500 holes before and after solder reflow, and the horizontal axis shows the number of times of solder reflow. For comparison, test results for a conventional printed wiring board are also shown. With the increase in the number of times of solder reflow, the connection resistance value of the conventional printed wiring board was significantly increased, whereas the connection resistance value of the printed wiring board of this embodiment was hardly changed.

FIG. 10 shows the press pressure and the uncured substrate having the pores of the closed structure when the porous substrate of this embodiment is heated and pressurized to form the uncured substrate material having the pores of the closed structure. The relationship between the average pore diameter and the porosity of the material was shown.
As the pressing pressure increased, the average pore diameter and the porosity decreased.

FIG. 11 shows the relationship between the average pore diameter of an uncured substrate material having pores of a closed structure and the amount of change in connection resistance due to solder reflow of a printed wiring board. On the vertical axis in FIG.
The amount of change in connection resistance per 500 holes of the via before and after the solder reflow is shown, and the average hole diameter is shown on the horizontal axis. The average pore size is 5
High reliability was obtained in the range of 20 μm.

FIG. 12 shows the relationship between the porosity of the uncured substrate material having pores of a closed structure and the amount of change in connection resistance due to solder reflow of the printed wiring board. The vertical axis in FIG. 12 shows the change in connection resistance per 500 holes before and after solder reflow, and the horizontal axis shows the porosity. High reliability was obtained when the porosity was in the range of 2 to 35%.

Note that, even when metal particles made of one or more of gold, copper, palladium, nickel and their alloys are used as the conductive material in the conductive paste in this embodiment in addition to silver, high connection reliability can be obtained. Sex was obtained.

Example 8 In this example, a 35 μm thick copper foil was used as the metal foil, the printed wiring board manufactured in Example 1 was used as the double-sided printed wiring board, and a 0.2 mm thick copper foil was used as the intermediate connector. An aramid epoxy sheet was used in which the conductive paste described in Example 1 was filled in the through holes and the recesses in the inner walls of the through holes. An intermediate connector is arranged above and below the double-sided printed wiring board, and copper foil is arranged above and below the double-sided printed circuit board.
Lamination was performed by heating and pressing at 0 ° C. and a pressure of 30 kg / cm ² for 1 hour. Next, the copper foil layer was etched by a known technique to form a pattern, and a four-layer printed wiring board was manufactured.

FIG. 13 shows the results of a solder reflow test of the multilayer printed wiring board obtained by the manufacturing method of this embodiment.
The vertical axis of FIG. 13 shows the amount of change in connection resistance per 500 holes before and after solder reflow, and the horizontal axis shows the number of times of solder reflow. In the multilayer printed wiring board obtained in this example, almost no change in the connection resistance value due to solder reflow was observed.

Example 9 In this example, the double-sided printed wiring board was the printed wiring board manufactured in Example 1, and the intermediate connector was 0.2 m.
An aramid epoxy sheet was used in which the conductive paste described in Example 1 was filled in the through holes of m and the recesses on the inner walls of the through holes. A double-sided printed wiring board is arranged above and below the intermediate connector, and using a hot press, the press temperature is 170 ° C. and the pressure is 30 kg /.
The laminate was heated and pressed at 1 cm ² for 1 hour to produce a 4-layer printed wiring board.

FIG. 14 shows the results of a solder reflow test of the multilayer printed wiring board obtained by the manufacturing method of this embodiment.
The vertical axis in FIG. 14 shows the amount of change in connection resistance per 500 holes before and after solder reflow, and the horizontal axis shows the number of times of solder reflow. In the multilayer printed wiring board obtained in this example, almost no change in the connection resistance value due to solder reflow was observed.

The double-sided printed wiring board in Examples 1 to 9 is not limited to the printed wiring board manufactured in Example 1, but may be a composite material of glass fiber and epoxy resin or a composite material of glass fiber and polyimide resin. It is also possible to use a printed wiring board made of a composite material of glass fiber and thermosetting polybutadiene resin (BT resin). In addition, as a conductive material in the conductive paste, other than silver, gold,
Similar results were obtained when metal particles composed of one or more of copper, palladium, nickel and their alloys were used.

Example 10 Aramid woven fabric, thermosetting and uncured phenolic resin, epoxy resin, BT resin, polyimide composite and aramid nonwoven fabric, and thermosetting and uncured phenolic resin, epoxy resin, respectively Via holes were formed by carbon dioxide laser on a total of eight types of single-layer substrates made of BT resin, BT resin and polyimide. Table 1 shows the laser processing conditions, the hole diameters at that time, and the structures in the holes for the eight types of single-layer substrates.

[0091]

[Table 1]

The conductive paste was placed on the release film of the substrate, and applied to a uniform thickness by squeezing with a urethane rubber squeegee using a screen printer. A suction device was placed under each hole-processed substrate through a 50 μm-thick medium paper, and the pressure was reduced to fill a conductive paste to form a filled via hole. All single layer substrates are 120
One having a thickness of about 140 μm was used. For the conductive paste, 85% by weight of copper powder having an average particle size of 3 microns,
A mixture obtained by kneading 12% by weight of a liquid epoxy resin and 2% by weight in total of a curing agent and an accelerator was used. The epoxy resin, curing agent, and accelerator can be selected from commercially available ones according to the paste use viscosity. With respect to the total number of embedded via holes, the number of via holes that were pierced when peeled from the medium paper on the stage after squeezing was compared for each single-layer substrate material. The results are shown in Table 1 above. From this result, it can be seen that the one having the via structure according to the present invention in which the hole was formed by the carbon dioxide gas laser was excellent in the paste holding property in the paste embedding.

A copper foil was adhered to both surfaces of the single-layer substrate and subjected to vacuum thermocompression bonding at 180 ° C. for 1 hour under a condition of 50 kg / cm ² , and thereafter, the copper foil was patterned to form a wiring to form a double-sided board. . Further, on both sides of this double-sided board, the above-mentioned filled via single-layer board was sandwiched between copper foils on both sides by vacuum thermocompression bonding under the same conditions as above, and the copper foil was patterned to form a circuit to form a four-layer structure. The circuit was subjected to a thermal shock test at -55 ° C. and 125 ° C. for 30 minutes each for 500 cycles, and 3000 vias sandwiched between copper foils in the circuit were selected to have a resistance value of 2 before and after the test.
Those that were more than doubled were counted as defective.
The results are shown in Table 1 above. From these results, it is understood that the substrate having the via structure of the present invention has excellent thermal shock resistance.

Example 11 Aramid woven fabric and thermosetting and uncured phenolic resin, epoxy resin, BT resin, polyimide composite and aramid nonwoven fabric and thermosetting and uncured phenolic resin and epoxy resin, respectively , BT resin, and polyimide, a total of eight types of single-layer substrates were subjected to via hole drilling with a YAG laser. Table 2 shows the laser processing conditions, the hole diameter at that time, and the structure in the hole.

[0095]

[Table 2]

A conductive paste was placed on the release film of the substrate, and applied to a uniform thickness by squeezing with a urethane rubber squeegee using a screen printer. A suction device was placed under each hole-processed substrate through a 50 μm-thick medium paper, and the pressure was reduced to fill a conductive paste to form a filled via hole. All single layer substrates are 120
One having a thickness of about 140 μm was used. As for the conductive paste, 87% by weight of silver powder having an average particle size of 4 microns,
A mixture obtained by kneading 10% by weight of a liquid epoxy resin and 3% by weight in total of a curing agent and an accelerator was used. The epoxy resin, the curing agent, and the accelerator can be selected from commercially available products according to the paste use viscosity as in Example 1. With respect to the total number of embedded via holes, the number of via holes that were pierced when peeled from the medium paper on the stage after squeezing was compared for each single-layer substrate material. The results are shown in Table 2 above. From this result, YAG
It can be seen that the laser-drilled via structure according to the present invention has excellent paste retention characteristics during paste embedding.

A copper foil was bonded to both surfaces of the single-layer substrate, and was subjected to vacuum thermocompression bonding at 180 ° C. for 1 hour at 50 kg / cm ² , and then the copper foil was patterned to form wiring to form a double-sided board structure. . Further, on both sides of this double-sided board, the above-mentioned filled via single-layer board was sandwiched between copper foils on both sides by vacuum thermocompression bonding under the same conditions as above, and the copper foil was patterned to form a circuit to form a four-layer structure. For those, a thermal shock test of 500 cycles of holding at −55 ° C. and 125 ° C. for 30 minutes each was performed, and 3000 vias sandwiched between copper foils were selected from the circuit, and the resistance value was more than doubled before and after the test. Those were counted as bad. The results are shown in Table 2 above. From these results, it is understood that the substrate having the via structure of the present invention has excellent thermal shock resistance.

(Example 12) Glass woven fabric, thermosetting and uncured phenolic resin, epoxy resin, BT resin, polyimide composite and aramid nonwoven fabric, and thermosetting and uncured phenolic resin, epoxy resin, respectively , BT resin, and polyimide were subjected to via drilling on a total of eight types of single-layer substrates using an excimer laser. Table 3 shows the laser processing conditions, the hole diameters at that time, and the structures in the holes for the eight types of single-layer substrates.

[0099]

[Table 3]

A conductive paste was placed on the release film of the substrate, and applied to a uniform thickness by squeezing with a urethane rubber squeegee using a screen printer. A suction device was placed under each hole-processed substrate through a 50 μm-thick medium paper, and the pressure was reduced to fill a conductive paste to form a filled via hole. All single layer substrates are 120
One having a thickness of about 140 μm was used. Note that the same conductive paste as in Example 1 was used. With respect to the total number of embedded via holes, the number of via holes that were pierced when peeled from the medium paper on the stage after squeezing was compared for each single-layer substrate material. The results are shown in Table 3 above. From these results, it can be seen that the one having the via structure according to the present invention in which the excimer laser is used for drilling is excellent in the paste holding property in the paste embedding.

A copper foil was adhered to both surfaces of this single-layer substrate and subjected to vacuum thermocompression bonding at 180 ° C. for 1 hour at 50 kg / cm ² , and then the copper foil was patterned to form wiring to form a double-sided board structure. . Further, on both sides of this double-sided board, the above-mentioned filled via single-layer board was sandwiched between copper foils on both sides by vacuum thermocompression bonding under the same conditions as above, and the copper foil was patterned to form a circuit to form a four-layer structure. For those, a thermal shock test of 500 cycles of holding at −55 ° C. and 125 ° C. for 30 minutes each was performed, and 3000 vias sandwiched between copper foils were selected from the circuit, and the resistance value was more than doubled before and after the test. Those were counted as bad. The results are shown in Table 3 above. From these results, it is understood that the substrate having the via structure of the present invention has excellent thermal shock resistance.

As described above, the printed wiring board of the present invention
Through holes provided in an uncured substrate material having holes of a closed structure and holes present inside the substrate material from the inner walls of the through holes are filled with a conductive paste in the recesses opened when the through holes are formed. Thereby, the anchor effect is increased, and the adhesion between the conductive paste and the wall surface of the through hole is improved. As a result, a printed wiring board having excellent thermal shock resistance can be realized.

[0103]

As described above, according to the present invention, a through-hole is formed in the thickness direction of the resin-impregnated fiber sheet substrate, and the through-hole is provided for electrical connection in the thickness direction of the substrate. A printed wiring board filled with the conductive resin composition of the above, wherein the substrate and the conductive resin composition are integrated, so that the conductive resin composition and the wall surface of the through hole of the substrate The adhesion is improved, and a highly reliable printed wiring board can be realized.

Next, according to the structure of the method for manufacturing a printed wiring board of the present invention, the laser beam is applied in the thickness direction of the uncured resin impregnated fiber sheet substrate material, both surfaces of which are covered with a cover film and have pores therein. A through hole is formed by light irradiation, the through hole is filled with a conductive paste, the cover film is removed, a metal foil is attached to at least one side of the substrate material, and then the substrate material is heated. Press and compress and harden to integrate the substrate material and conductive paste,
Thereafter, by patterning the metal foil into a predetermined shape, a circuit board can be efficiently and rationally manufactured. In particular, since the through-hole is formed by irradiating a laser beam, precision fine processing is possible, and unlike the conventional drilling, no cutting chips are generated and a clean manufacturing environment can be maintained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a circuit board according to a first embodiment of the present invention.

FIGS. 2A to 2G are process cross-sectional views illustrating a method of manufacturing a circuit board according to Embodiment 1 of the present invention.

3 (a) to 3 (h) are cross-sectional views illustrating steps of a multilayer circuit board according to Embodiment 2. FIG.

FIGS. 4A to 4F are process cross-sectional views of a method for manufacturing a printed wiring board according to a third embodiment of the present invention.

FIGS. 5A to 5H are process cross-sectional views illustrating a method for manufacturing a printed wiring board in Embodiment 4 of the present invention.

FIGS. 6A to 6E are process cross-sectional views illustrating a method for manufacturing a printed wiring board in Embodiment 5 of the present invention.

FIGS. 7A to 7C are schematic cross-sectional views of an integrated structure of a substrate material and a conductive resin composition according to Example 6 of the present invention.

8 (a) to 8 (e) are process cross-sectional views illustrating a conventional method for manufacturing a double-sided printed wiring board.

FIG. 9 is a diagram showing a reflow test result of a printed wiring board in Example 7 of the present invention.

FIG. 10 is a diagram showing the relationship between the pressing pressure for compressing a porous substrate and the average pore diameter and porosity of an uncured substrate material having pores of a closed structure in Example 7 of the present invention.

FIG. 11 is a diagram showing the relationship between the average pore diameter of an uncured substrate material having pores having a closed structure and the amount of change in resistance due to solder reflow of a printed wiring board in Example 7 of the present invention.

FIG. 12 is a diagram showing the relationship between the porosity of an uncured substrate material having pores of a closed structure and the amount of resistance change due to solder reflow of a printed wiring board in Example 7 of the present invention.

FIG. 13 is a view showing a result of a solder reflow test of a multilayer printed wiring board in Example 8 of the present invention.

FIG. 14 is a diagram showing a result of a solder reflow test of a multilayer printed wiring board in Example 9 of the present invention.

[Explanation of symbols]

Reference Signs List 101 Insulating substrate 102 Metal foil (circuit pattern) 103 Conductive paste 103a Part of binder resin 201,402 Protective film 202,401,503 Porous base material 202a, 404,504 Hole 203,405 Through hole 204,407, 505 Conductive paste 204a, 407a Partial resin of conductive paste 205, 304, 305, 408, 501, 502 Copper foil 205a, 409 Circuit pattern 206, 303, 511 Circuit board 301, 302, 509, 510 Intermediate connector 306, 514 Multilayer circuit board 406 Recess of through hole

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Koji Kawakita 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. In-company (72) Inventor Seiichi Nakatani 1006 Kadoma, Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (56) References JP-A-3-145796 (JP, A) JP-A 1-228197 (JP, A JP-A-3-75557 (JP, A) JP-A-4-154187 (JP, A) JP-A-62-283695 (JP, A) JP-A-54-38562 (JP, A) JP-A-59-1983 175191 (JP, A) JP-A-63-265488 (JP, A) JP-A-6-268345 (JP, A)

Claims (36)

(57) [Claims] 1. A resin-impregnated fiber sheet substrate in a thickness direction,
A printed wiring board, wherein a through hole is formed, and the through hole is filled with a conductive resin composition for making electrical connection in a thickness direction of the substrate, wherein the resin impregnated fiber sheet base is provided.
The plate material has an air hole of a closed structure inside, and the substrate and the
The conductive resin composition means that the conductive resin composition is
Fills multiple recesses formed from hermetically sealed holes in the plate
A printed wiring board, wherein the printed wiring board is integrated by a structure protruding into the substrate in a state where the printed circuit board is formed. 2. A resin-impregnated fiber sheet substrate in the thickness direction,
A through-hole is formed, and the through-hole has an electric current in the thickness direction of the substrate.
Filled with a conductive resin composition for pneumatic connection
Printed wiring board, wherein the conductive resin composition,
A composition of metal fine particles and a resin, and wherein the metal fine particles
In the range of the average particle diameter of 0.2 to 20 μm,
Together with the and I Ri said substrate infiltrated structure resin in said substrate is a component of the conductive resin composition guide is
Characterized by being integrated with the conductive resin composition
Printed wiring board. 3. The resin impregnated fiber sheet substrate in the thickness direction,
A through-hole is formed, and the through-hole has an electric current in the thickness direction of the substrate.
Filled with a conductive resin composition for pneumatic connection
Printed wiring board, wherein the conductive resin composition,
A composition of metal fine particles and a resin, and wherein the metal fine particles
In the range of the average particle diameter of 0.2 to 20 μm,
With some, and the resin which is one component of the conductive resin composition by the impregnation resin of the substrate is self-adhesive covalently bonded, to the substrate and the conductive resin composition
Is a printed wiring board characterized by being integrated. 4. The resin impregnated fiber sheet substrate in the thickness direction,
A through-hole is formed, and the through-hole has an electric current in the thickness direction of the substrate.
Filled with a conductive resin composition for pneumatic connection
Printed wiring board, wherein the heat-resistant synthetic fiber constituting the substrate protrudes into the conductive resin composition.
The substrate and the conductive resin composition are integrated.
A printed wiring board, characterized in that: 5. The thermosetting resin according to claim 1, wherein the resin impregnated on the substrate and the resin which is a component of the conductive resin composition are both thermosetting resins.
A printed wiring board according to any one of claims 1 to 4 . 6. The printed wiring board according to claim 5 , wherein the thermosetting resin is at least one selected from an epoxy resin, a thermosetting polybutadiene resin, a phenol resin, and a polyimide resin. Resin-impregnated fiber sheet 7. substrate, heat-resistant synthetic fibers and printed wiring board according to any one of claims 1 to 6 is obtained using at least one selected from glass fibers. 8. The printed wiring board according to claim 7 , wherein the heat-resistant synthetic fiber uses at least one selected from an aromatic polyamide fiber and a polyimide fiber. 9. The printed wiring board according to claim 1, wherein the resin-impregnated fiber sheet of the substrate is a nonwoven fabric. 10. The fine metal particles in the conductive resin composition,
10. The method according to claim 1, which is at least one selected from gold, silver, copper, palladium, nickel and alloys thereof.
Printed wiring board according to either. 11. The method of claim abundance of metal particles of the conductive resin composition is in the range of 80 to 92.5 wt% 1-1
0. The printed wiring board according to any one of 0 . 12. The size of the fine metal particles of the conductive resin composition is in the range of average particle diameter 0.2~20μm printed wiring board according to any one of claims 1,4,5. 13. The conductive resin composition size of the through hole is filled with the printed wiring board according to any one of claims 1 to 12 in the range of average diameter 50 to 300 [mu] m. 14. A surface of the substrate, and a printed wiring board according to any one of claims 1 to 13 in which the circuit pattern to the distal end of the conductive resin composition is formed. 15. We covered on both sides with a cover film, and the thickness direction of the uncured resin-impregnated fiber sheet substrate material having an internal pore, a through hole is formed by laser beam irradiation, conductive in the through-hole The paste is filled, then the cover film is removed, a metal foil is attached to at least one side of the substrate material, and then the substrate material and the conductive paste are heated and pressurized to be cured by compression. A method for manufacturing a printed wiring board, comprising: integrating and then patterning the metal foil into a predetermined shape. 16. A method of manufacturing a printed wiring board according to claim 1 5 of bonding a metal foil on both sides of the substrate material. 17. We covered on both sides with a cover film, and the thickness direction of the uncured resin-impregnated fiber sheet substrate material having an internal pore, a through hole is formed by laser beam irradiation, conductive in the through-hole Filling with paste, then removing the cover film and preparing two intermediates in which a metal foil is attached to one surface of the substrate material, and arranged so that the metal foil surface of the intermediate is outside A circuit board having at least two or more wiring patterns in the center is sandwiched, and the board material and the conductive paste are integrated by heating and pressurizing and compressing and hardening the entire board. A method of manufacturing a multilayer printed wiring board for patterning into a predetermined shape. 18. We covered on both sides with a cover film, and the thickness direction of the uncured resin-impregnated fiber sheet substrate material having an internal pore, a through hole is formed by laser beam irradiation, conductive in the through-hole Filling with paste, then removing the cover film to create an intermediate connector, sandwiching the intermediate connector between a plurality of double-sided printed wiring boards,
A method of manufacturing a multilayer printed wiring board in which the substrate material and the conductive paste are integrated by heating and pressurizing the whole to compress and harden. 19. uncured resin impregnated fiber sheet substrate material inside the pores, claim 15 and 17 also is a vacancy closed structure
19. The method for manufacturing a printed wiring board according to item 18 . 20. pore diameter of the substrate material of the uncured having pores of the sealed structure is 5~20μm claim 15, 17 also
19. The method for manufacturing a printed wiring board according to item 18 . 21. The method for producing a printed wiring board according to claim 15 , wherein the porosity of the uncured substrate material having pores is 2 to 35%. 22. The heating temperature of the substrate material is from 170 to 260.
The method for producing a printed wiring board according to claim 15, 17 or 18 , wherein the temperature is in the range of ° C. 23. The pressing force of the substrate material is 20 to 80 kg /
19. The method for manufacturing a printed wiring board according to claim 15, 17 or 18 , wherein the range is cm ² . 24. The method according to claim 15, wherein a part of the fiber in the substrate material is left in the through hole by irradiating the laser beam.
19. The method for manufacturing a printed wiring board according to item 18 . 25. Use of a composition of fine metal particles and a resin as the conductive resin composition, and when filling the through-hole with the conductive resin composition, a resin which is one component of the conductive resin composition is coated on the substrate. 18. The method according to claim 15, 17 or 17,
19. The method for manufacturing a printed wiring board according to item 18 . 26. A resin, which is a component of the conductive resin composition, and a resin of substantially the same system as the impregnating resin for the substrate,
Claim be integrated by self-adhesive by a covalent bond 1
19. The method for producing a printed wiring board according to 5, 17 , or 18 . 27. Both the impregnated resin of the substrate and the resin which is one component of the conductive resin composition are thermosetting resins, and at least one selected from epoxy resin, thermosetting polybutadiene resin, phenol resin and polyimide resin. The method for producing a printed wiring board according to claim 15, 17 or 18 . 28. The method according to claim 15 , wherein the method of filling the through hole with the conductive resin composition is a roll coating method.
Or the method for manufacturing a printed wiring board according to 18 . 29. The method for manufacturing a printed wiring board according to claim 15 , wherein the resin-impregnated fiber sheet of the substrate uses at least one selected from heat-resistant synthetic fibers and glass fibers. 30. The method for manufacturing a printed wiring board according to claim 29 , wherein the heat-resistant synthetic fiber uses at least one selected from an aromatic polyamide fiber and a polyimide fiber. 31. The method for manufacturing a printed wiring board according to claim 15 , wherein the resin-impregnated fiber sheet of the substrate is a nonwoven fabric. 32. The fine metal particles in the conductive resin composition,
The method for manufacturing a printed wiring board according to claim 25 , wherein the method is at least one selected from gold, silver, copper, palladium, nickel, and an alloy thereof. 33. The method for producing a printed wiring board according to claim 25 , wherein the amount of the metal fine particles in the conductive resin composition is in the range of 80 to 92.5% by weight. 34. The method for producing a printed wiring board according to claim 25 , wherein the size of the metal fine particles in the conductive resin composition is in the range of 0.2 to 20 μm in average particle diameter. 35. The method for producing a printed wiring board according to claim 15 , wherein the size of the through hole filled with the conductive resin composition is in the range of 50 to 300 μm in average diameter. 36. The laser beam is a carbon dioxide gas laser, Y
The method for manufacturing a printed wiring board according to claim 15, 17 or 18 , which is at least one selected from an AG laser and an excimer laser.