JP2003318546A - Multilayer wiring board, base material for the same and their manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base material for a multilayer wiring board by which a thin multilayer wiring board can be obtained without failing connection reliability between a conductive resin composition and a conductive circuit and lowering the flatness of the board. <P>SOLUTION: The diameter of a conductive layer 14b of a through hole 14 is made smaller than those of an insulation layer and an adhesion layer part 14a, and conductive connection between a conductive resin composition 15 and a conductive layer 12 is ensured on the rear surface 12a of the conductive layer 12, and then the conductive layer 14b is also filled with the conductive resin composition 15 in addition to the insulation layer and the adhesion layer part 14a. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer wiring board (multilayer printed wiring board), a base material for a multilayer wiring board, and a method for manufacturing the same, and in particular, a multilayer flexible print capable of high-density mounting such as flip-chip mounting. The present invention relates to a multilayer wiring board such as a wiring board, a base material for a multilayer wiring board, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A flexible printed wiring board (FPC) using a polyimide film having high heat resistance, electric insulation and high flexibility as an insulating layer material is known. Further, a multilayer FPC in which FPCs are laminated in multiple layers and interlayer conduction is achieved by through holes has been developed.

In a multi-layer FPC using through holes, the degree of freedom in wiring design is low due to the restriction of the interlayer connection position, and the chip cannot be mounted on the through holes.
There is a limit to increase the packaging density, and it has become impossible to meet the recent demand for higher density packaging.

In order to cope with this, the IVH (Interstitial V
ia Hole) to enable via-on-via resin multilayer printed wiring boards, for example, ALIVH (Any Layer Intersti) from Matsushita Electric Industrial Co., Ltd.
Tial Via Hole) and a polyimide composite multilayer build-up integrated circuit board (MOSAIC) of Sony Chemical Co., in which FPCs made of polyimide are stacked in multiple layers by a build-up method without using through holes, have been developed.

In addition, a general-purpose copper-clad resin base material (laminated material) having a polyimide film as an insulating layer and a conductive layer made of copper foil attached to one surface of the insulating film is used as a starting base material, and an IVH structure is formed by a simple process. There is proposed a structure and a manufacturing method for obtaining the multilayer FPC (see, for example, Patent Document 1).

In the base material for a multilayer wiring board disclosed in Patent Document 1, a through hole is formed in a copper clad resin base material having a copper foil provided on one surface of an insulating layer, and then a conductive resin composition ( An IVH portion as shown in FIG. 9 is formed by filling a resin-based conductive paste) from the copper foil side by a printing method such as a screen printing method.

In FIG. 9, 101 is an insulating layer,
Reference numeral 102 denotes a copper foil portion, 104 denotes a through hole, and 105 denotes a conductive resin composition filled in the through hole 104.

When the aperture of the mask (stencil) at the time of screen printing is made larger than the IVH diameter, a certain degree of alignment accuracy can be provided at the time of printing, and a conductive resin is formed on the copper foil portion 102. Composition 105
By the head-shaped portion 1 having a size corresponding to the aperture of the mask
05A is formed.

The through hole 1 is formed by the head-shaped portion 105A.
04 filled with conductive resin composition 105 and copper foil portion 10
The contact area with 2 can be enlarged. In addition, the presence of the head-shaped portion 105A can prevent the conductive resin composition 105 filled in the through hole 104 from falling off from the through hole 104.

[0010]

[Patent Document 1] Japanese Patent Laid-Open No. 2002-353621

[0011]

However, in the base material for a multilayer wiring board as disclosed in Patent Document 1, the copper foil portion 102 of the conductive resin composition 105 as shown in FIG. 9 is used.
Due to the thickness of the upper portion, that is, the head-shaped portion 105A, in the case where the conductive resin composition 105 is cured and then laminated and laminated for multilayering, the thickness of the circuit portion is formed by a copper foil.
Above the copper foil of the conductive resin composition 105 (head-shaped portion 1
The thickness of the adhesive layer is sufficient to fill the thickness including the thickness of 05A), and if the adhesive layer is not thickened, the surface smoothness of the multilayer wiring board will be deteriorated.

Therefore, in a general-purpose copper-clad resin substrate in which a polyimide film is used as an insulating layer and a conductive layer made of copper foil is attached to one surface of the polyimide film, the insulating layer has a thickness of 15 to 30.
μm, and the thickness of the copper foil is about 5 to 20 μm, an adhesive layer having a thickness of about 15 to 30 μm is required, which leads to thickening of the substrate due to thickening of the adhesive layer. It will be.

On the other hand, it has been considered that the conductive resin composition is laminated in a soft state before curing so that the conductive resin composition and the copper foil of the other layer are brought into close contact with each other.

However, when this is applied to the base material for a multilayer wiring board shown in Patent Document 1, as shown in FIG. 10, the conductive resin composition 105 is provided above the copper foil portion 102. The portion (head-shaped portion 105A) is excessively crushed by the stacking pressure P during multilayer stacking and spreads in a crushed state.

For this reason, it is difficult to make the size of the head-shaped portion 105A uniform when viewed from the surface of the substrate, and the conductive resin composition of the head-shaped portion 105A spreads to the other wiring portion 102 '. This may result in short circuit.

The present invention has been made in view of the above-mentioned problems, and it does not impair the contact reliability between the conductive resin composition and the conductive circuit portion, and does not reduce the smoothness of the substrate, and thus thin multilayer wiring is provided. The substrate can be obtained, and even if a reliability test such as exposure to high temperature is performed, no problems such as peeling and peeling occur, and the conductive paste filled in the via hole and the conductive circuit section are also prevented. It is an object of the present invention to provide a base material for a multilayer wiring board capable of increasing a contact area, a method for manufacturing the same, and a multilayer wiring board.

[0017]

In order to achieve the above object, the base material for a multilayer wiring board according to the present invention is provided with a conductive layer forming a wiring pattern on one surface of an insulating base material. A material for a multilayer wiring board in which a through hole penetrating the material and the conductive layer is filled with a conductive resin composition for obtaining interlayer conduction, and the diameter of the conductive layer portion of the through hole is an insulating base material. The diameter of the portion is smaller than that of the portion, and the conductive resin composition is filled in all of the insulating base material portion and the conductive layer portion of the through hole.

According to this base material for a multilayer wiring board, the conductive contact between the conductive layer and the conductive resin composition is made on the back side of the conductive layer due to the difference in diameter between the insulating base material portion of the through hole and the conductive layer portion. The structure is taken, and it is freed from various problems derived from securing the contact area between the portion of the conductive resin composition above the conductive layer and the conductive layer.

Since the conductive resin composition is filled not only in the insulating base material portion (via hole) of the through hole but also in the conductive layer portion, a cavity is not formed inside the multilayer wiring board after the lamination. Even if a reliability test such as exposure to a high temperature is performed, no trouble such as peeling or peeling occurs. At the same time, the contact area between the conductive paste filled in the via hole and the conductive layer is increased by the area of the inner peripheral surface of the conductive layer portion.

In order to achieve the above object, the base material for a multilayer wiring board according to the present invention has a conductive layer forming a wiring pattern on one surface of an insulating base material and an interlayer adhesive for the other surface. Which is provided with an adhesive layer and is filled with a conductive resin composition for obtaining interlayer conduction in a through hole penetrating the conductive layer, the insulating substrate and the adhesive layer, , The diameter of the conductive layer portion of the through hole is smaller than the diameters of the insulating base material portion and the adhesive layer portion, and the conductive resin composition for all of the insulating base material portion, the adhesive layer portion and the conductive layer portion of the through hole Is filled.

According to this base material for a multilayer wiring board, the conductive contact between the conductive layer and the conductive resin composition can be obtained from the difference in the diameter between the insulating base material portion of the through hole and the adhesive layer portion and the conductive layer portion.
The structure is taken on the back side of the conductive layer, and is free from various problems derived from securing the contact area between the conductive resin composition and the portion above the conductive layer.

Since the conductive resin composition is filled not only in the insulating base material portion and the adhesive layer portion (via hole) of the through hole but also in the conductive layer portion, after the lamination, a cavity is formed inside the multilayer wiring board. Even if a reliability test such as exposure to a high temperature is performed, problems such as peeling and peeling do not occur. At the same time, the contact area between the conductive paste filled in the via hole and the conductive layer is increased by the area of the inner peripheral surface of the conductive layer portion.

In the base material for a multilayer wiring board according to the present invention,
The insulating base material is made of a flexible resin film such as polyimide, and a general-purpose copper-clad resin base material having a conductive layer made of copper foil attached to one surface of the flexible resin film is used as a starting base material. can do. The adhesive layer may be made of thermoplastic polyimide or a thermoplastic polyimide having a thermosetting function.

Further, it is preferable that the conductive resin composition filled in the through-holes is projected toward the interlayer adhesion surface side to form a projection of the conductive resin composition. The protrusion has the effect of lowering the electrical connection resistance between the layers by pressing or piercing the conductive layer of the adjacent layer.

A substrate for a multilayer wiring board according to the present invention comprises at least one substrate for a multilayer wiring board according to the above-mentioned invention,
It is one that includes.

In order to achieve the above-mentioned object, in the method for manufacturing a base material for a multilayer wiring board according to the present invention, a laminated material having a conductive layer forming a wiring pattern on one surface of an insulating base material is electrically conductive. A piercing step of piercing a through hole having a layer portion having a diameter smaller than that of the insulating base material portion, and a filling step of filling the conductive resin composition into all of the insulating base material portion and the conductive layer portion of the through hole. Have.

In order to achieve the above-mentioned object, the method for manufacturing a base material for a multilayer wiring board according to the present invention comprises a conductive layer forming a wiring pattern on one surface of an insulating base material and an interlayer on the other surface. In a laminated material provided with an adhesive layer for adhesion, a perforation step of perforating a through hole in which the diameter of the conductive layer portion is smaller than the diameters of the insulating base material portion and the adhesive layer portion, and the conductive resin composition is penetrated. And a filling step of filling all of the insulating base material portion, the adhesive layer portion, and the conductive layer portion of the hole.

As a preferable perforating step in the method for manufacturing a base material for a multilayer wiring board according to the present invention, a resin portion other than the conductive layer portion is perforated by laser beam irradiation, and after the perforation is completed, the conductive layer portion is perforated. Either in the process of making a small hole to form a through hole, or by irradiating the surface opposite to the conductive layer with a laser beam having a laser intensity distribution in the beam diameter direction, and calibrating the resin part other than the conductive layer. It is possible to select any one of the steps of forming holes having a large diameter in the conductive layer portion at one time to form the through holes.

Further, in the method for manufacturing a base material for a multilayer wiring board according to the present invention, it is preferable to have a desmear step after the perforation step by laser beam irradiation in order to remove smear generated by laser perforation.

The filling step in the method for producing a substrate for a multilayer wiring board according to the present invention may be a step of filling the through hole with a conductive resin composition from the side opposite to the conductive layer by squeezing.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2 show the basic structure of a base material for a multilayer wiring board according to an embodiment of the present invention.

The base material for a multilayer wiring board shown in FIG. 1 has a conductive layer 12 made of copper foil or the like forming a wiring pattern on one surface of an insulating resin layer 11 forming an insulating base material and the other surface on the other surface. Adhesive layers 13 for inter-layer adhesion are provided respectively, and the adhesive layers 1
Through hole 1 penetrating through 3, insulating resin layer 11 and conductive layer 12
4 are drilled. The through hole 14 is filled with the conductive resin composition 15 to form an IVH (via hole).

In the FPC, the insulating resin layer 11 is made of a flexible resin film such as a polyimide film made of wholly aromatic polyimide (API) or a polyester film. The three-layer structure of the insulating resin layer 11, the conductive layer 12, and the adhesive layer 13 has a copper foil (conductive layer 1) of a polyimide part (insulating resin layer 11) of a general-purpose polyimide base material with a single-sided copper foil.
The adhesive layer 13 may be formed by adhering a polyimide adhesive on the surface opposite to that of 2).

Through hole 1 formed in the base material for a multilayer wiring board
4, the diameter of a portion (via hole) 14a penetrating the adhesive layer 13 and the insulating resin layer 11 is a normal via hole diameter, and the diameter of a portion (small hole) 14b penetrating the conductive layer 12 is an adhesive layer 13 And a portion 1 penetrating the insulating resin layer 11
The diameter is smaller than the diameter of 4a.

The adhesive layer 13 can be formed by applying a thermoplastic polyimide or a film obtained by adding a thermosetting function to a thermoplastic polyimide, in addition to applying the adhesive. In the case of thermoplastic polyimide, it is preferable to use one having a high glass transition point in consideration of the heat resistance of the substrate.

In addition to the polyimide film, the insulating resin layer 11 may be made of epoxy-based or imide-based prepreg as an insulating material. In that case, the insulating resin layer 11 may be used as an adhesive material. Since it functions, it is not necessary to separately form the adhesive layer 13.

The conductive resin composition 15 is prepared by mixing a metal powder having a conductive function into a resin binder and mixing it with a viscous medium containing a solvent to form a conductive paste from the insulating resin layer 11 side by squeezing or the like. The through holes 14 are evenly filled and filled with. That is, the adhesive layer-insulating resin layer portion 14 a and the conductive layer portion 14 of the through hole 14
The conductive resin composition 15 is evenly filled in all of b.

Since the conductive resin composition 15 conducts electricity on the back surface 12a of the conductive layer 12 and does not conduct electricity on contact with the upper surface of the conductive layer 12, it projects above the conductive layer 12. No need for extended extensions.

The conductive layer 12, that is, the copper foil portion, has a hole 14 smaller than the resin portion (insulating resin layer 11 + adhesive layer 13).
Although b is provided, when the copper foil portion 102 and the resin portion (insulating layer 101) have the same hole diameter as shown in FIG. 11, the copper foil portion 102 is insulated from the copper foil portion 102. This is because the contact portion with the layer 101 is only the hole wall surface portion 102A of the copper foil portion 102, and the reliability of the conductive connection between the copper foil portion 102 and the conductive resin composition 105 becomes poor.

Further, as shown in FIG. 12, when holes are not formed in the copper foil part 102 but only the resin part insulating layer 101 is formed, the conductive paste is filled with holes by squeezing or the like. This is because the IVH is not sufficiently deaerated during filling, bubbles h remain in the IVH, and the contact area between the copper foil portion 102 and the conductive resin composition 105 becomes unstable.

Small holes 14b provided in the conductive layer 12
Functions as an air bleed hole, and when filling the filling with the conductive paste, the air bubbles are surely discharged from the small holes 14b, and the contact area between the conductive layer 12 and the conductive resin composition 15 can be accurately secured.

In the base material for a multilayer wiring board shown in FIG. 2, the insulating resin layer 21 itself, which is an insulating base material, has adhesiveness for interlayer adhesion. This base material is the insulating resin layer 2
A conductive layer 22 made of copper foil or the like forming a wiring pattern is provided on one surface of No. 1 and a through hole 24 penetrating the insulating resin layer 21 and the conductive layer 22 is formed. The through hole 24 is filled with a conductive resin composition 25, and IVH (via hole) is formed.
Is formed.

In the FPC, the insulating resin layer 2 having adhesiveness
1 is composed of a thermoplastic polyimide (TPI) or a thermoplastic polyimide having a thermosetting function.
In the case of thermoplastic polyimide, it is preferable to use one having a high glass transition point in consideration of the heat resistance of the substrate.

Of the through holes 24, the diameter of a portion (via hole) 24a penetrating the insulating resin layer 21 is a normal via hole diameter, and a portion (small hole) 2 penetrating the conductive layer 22.
The diameter of 4b is smaller than the diameter of the portion 24a penetrating the insulating resin layer 21.

The conductive resin composition 25 is prepared by mixing a metal powder having a conductive function into a resin binder and mixing it with a viscous medium containing a solvent to form a conductive paste from the insulating resin layer 21 side by squeezing or the like. The through holes 24 are evenly filled and filled. That is, the conductive resin composition 25 is evenly filled in all of the insulating resin layer portion 24a and the conductive layer portion 24b of the through hole 24.

Since the conductive resin composition 25 conducts electricity on the back surface 22a of the conductive layer 22 and does not conduct electricity on contact with the upper surface of the conductive layer 22, it projects above the conductive layer 22. No need for extended extensions.

Small holes 24b provided in the conductive layer 22
Functions as an air bleed hole, and the bubbles are surely discharged from the small holes 24b during filling and filling, and the contact area between the conductive layer 22 and the conductive resin composition 25 can be accurately secured.

In both of the base materials for multilayer wiring boards shown in FIGS. 1 and 2, the through holes 14 and 24 formed by the large holes 14a and 24a and the small holes 14b and 24b are laser drilled by laser beam irradiation. It can be formed by processing. In addition, a large hole 14 can be formed by a combination of etching, laser beam irradiation and etching.
a, 24a and small hole 14b, 24b through hole 1
4, 24 can be processed.

In the case of laser drilling, first, a large hole 14a is formed in the insulating resin layer 11 and the adhesive layer 13 or a large hole 24a is formed in the insulating resin layer 21 by laser beam irradiation.
After piercing, a small hole 14b or 24b is bored in the conductive layer 12 or 22 again by laser beam irradiation, and then the conductive resin composition (conductive paste) 1
Although the method of filling 5 and 25 in the through holes 14 and 24 may be used, the laser beam intensity (laser intensity) is usually used.
Is higher (stronger) in the center of the beam when viewed in the beam radial direction,
Since the circumference is low (weak), this is used to form the small hole 14 in the central portion formed in the conductive layers 12 and 22.
b and 24b and the holes 14a and 24a having a large resin portion can be formed at one time. This makes it possible to efficiently obtain the via hole having the above structure in a shorter time.

Further, the in-plane distribution of the beam intensity is
As shown in FIGS. 8 (a) and 8 (b), it is possible to more reliably perform the above-mentioned drilling by using a two-step laser beam in which the vicinity of the center of the laser-processed surface is strong and the peripheral part is weak. A structural IVH can be formed. A laser beam having such a two-step laser intensity can be obtained by passing the laser beam through a filter having a high beam transmittance in the central portion and a low beam transmittance in the peripheral portion before narrowing down the laser beam.

FIG. 3 shows one embodiment of the multilayer wiring board according to the present invention. This multilayer wiring board uses the base material for a multilayer wiring board shown in FIG.
As the base material 10B for the second layer A and the base material 10B for the second layer, the base material 10 for the first layer is laminated by the adhesive layer 13 of the base material 10A for the first layer.
A and the second-layer base material 10B are adhesively bonded to each other.
On the adhesive layer 13 of the second layer base material 10B, a conductive layer 16 made of copper foil forming a wiring pattern on the surface is formed.

The through holes 14 filled with the conductive resin composition 15 form IVH, and the conductive resin composition 15 allows the conductive layer 15 of each layer or the conductive layers 15 and 16 to be electrically connected to each other.

In addition to the adhesive layer-insulating resin layer portion 14a of the through hole 14, the conductive resin composition 15 is added to the conductive layer portion 14
Since it is also filled in b, no void is formed inside the multilayer wiring board, and even if a reliability test such as exposure to a high temperature is performed, no problems such as peeling and peeling occur.

Since the conductive layer portion 14b is also filled with the conductive resin composition 15, the conductive resin composition 15 filled in the via hole by the area of the inner peripheral surface of the conductive layer portion.
The effect of increasing the contact area between the conductive layer 15 and the conductive layer 15 is also obtained.

Since the conductive layer portion 14b is also filled with the conductive resin composition 15, an anchoring effect can be obtained. Thereby, the conductive resin composition 15 is less likely to be peeled from the insulating resin layer 11 and the adhesive layer 13 due to the thermal stress caused by the difference in the thermal expansion coefficient of the insulating resin layer 11, the adhesive layer 13, and the conductive resin composition 15. Durability and reliability are improved.

A multilayer wiring board having the same function can be obtained by stacking a plurality of base materials for a multilayer wiring board shown in FIG. 2 and adhering them to each other.

Further, as shown in FIGS. 4 and 5,
The conductive resin composition 15 filled in the through holes 14 and 24,
25 is projected to the side of the interlayer adhesion surface to form the conductive resin composition 1
It is preferable to form the protrusions 15A and 25A by 5 and 25.

The protrusions 15A and 25A are pressed or pierced into the adjacent conductive layers to reduce the electrical connection resistance between the layers.

Next, one embodiment of the multilayer wiring board base material shown in FIG. 1 and a method of manufacturing a multilayer wiring board using the multilayer wiring board base material will be described with reference to FIGS. 6 and 7. To do.

As shown in FIG. 6A, a single-sided copper-clad laminate (CCL) having a conductive layer 12 made of copper foil forming a wiring pattern on one surface of an insulating resin layer (polyimide film) 11 is formed. As a starting material, as shown in FIG. 6B, an adhesive layer 13 is formed on the insulating resin layer 11 side by adhering a film obtained by applying a thermosetting function to plastic polyimide or thermoplastic polyimide.

Next, as shown in FIG. 6C, the conductive layer 12 is etched to form a wiring pattern (circuit pattern) by the conductive layer 12.

Next, as shown in FIG. 6 (d), a PET masking tape 17 is attached on the adhesive layer 13 and laser drilling is performed to obtain a pattern as shown in FIG. 6 (e). , PET masking tape 17, adhesive layer 1
3, through hole 14 penetrating insulating resin layer 11 and conductive layer 12
To drill.

The through hole 14 is a portion 1 penetrating the PET masking tape 17, the adhesive layer 13, and the insulating resin layer 11.
The diameter of 4a is the usual via hole diameter, for example, 100μ.
m, the diameter of the portion 14b penetrating the conductive layer 12 is about 30 to 50 μm, which is smaller than the via hole diameter.

When the through hole 14 is completed, the through hole 1
Desmear is carried out to remove the smear 18 due to the resin or the oxide of the copper foil, etc., which is caused by the perforations remaining inside 4. The desmear can be performed by soot etching using plasma or wet desmear using a permanganese chlorine-based desmear solution.

When desmearing is completed, as shown in FIG. 6 (f), a squeegee plate (squeegee plate) 50 as used in screen printing is shown in FIG. 6 (g). From the surface side of the PET masking tape 17 to the conductive resin composition (conductive paste) 15
Are squeezed to fill the through holes 14 with holes.

FIG. 6 (h) shows a state where the filling of the conductive resin composition 15 is completed. This filling of the conductive resin composition is sufficiently performed without gaps in the conductive layer portion 14b in addition to the adhesive layer-insulating resin layer portion 14a of the through hole 14.

As the conductive resin composition 15, a silver paste was used in order to avoid oxidation due to heating in the subsequent steps. At this time, when the one having a viscosity of 300 dPa · s was used, the conductive paste could be properly filled and filled without coming off from the small holes 14b of the copper foil portion (conductive layer 12). As the conductive resin composition 15, it is possible to use a conductive paste made of a copper filler or a carbon mixture other than the silver paste.

In this embodiment, since the PET masking tape 17 is attached to the surface of the base material, the squeegee plate 50 does not use a metal mask or a screen mask.
May be directly contacted with the substrate for squeezing,
Of course, squeezing through a metal mask or a screen mask can reduce waste of the conductive resin composition.

At the time of this squeezing, air bubbles are discharged from the small holes 14b of the copper foil portion (conductive layer 12), and no air bubbles remain in the through holes 14, and the copper foil portion (conductive layer 12) and the conductive layer 12 are electrically conductive. Of the conductive resin composition 15 to the back surface 12 of the conductive layer 12
a is sufficient.

As described above, if the diameter of the large hole 14a of the resin portion of the through hole 14 is about 100 μm, the diameter of the small hole 14b of the copper foil portion may be about 30 to 50 μm. The diameter of the conductive resin composition 15
In addition to the requirement from the contact resistance with the conductive resin composition 1
Depending on various properties such as viscosity and thixotropy of No. 5, the selection is made so as to avoid remaining of air bubbles and dropping of the conductive resin composition 15.

Next, as shown in FIG. 6 (i), P having the rest of the conductive resin composition 15 attached to the surface
Peel off the ET masking tape 17. As a result, one base material 10 is completed. This base material 10A has the conductive resin composition 1 which is protruded from the surface of the adhesive layer 13, that is, the interlayer adhesive surface side by peeling off the PET masking tape 17.
5 to form a protrusion 15A. The height of the protrusion 15A is equivalent to the thickness of the PET masking tape 17.

This base material 10A is used as the base material of the first layer, and FIG.
(A) to (i) the base material 10B manufactured by the same manufacturing method as before, and the conductive layer 16 made of copper foil are aligned by a proper alignment method, respectively, and are laminated by thermocompression bonding (lamination). 7 (j), (k)
Multiple layers are achieved, as shown in.

At the time of lamination, by heating and pressing the base material while exposing it to a vacuum, the followability of the adhesive layer 13 to the irregularities of the circuit pattern by the conductive layer 12 can be enhanced. In addition, the conductive resin composition 15 can be laminated in a soft state, and the conductive resin composition 15 and the copper foil of the other layer can be brought into close contact with each other.

Finally, as shown in FIG. 7 (l), the outermost conductive layer 16 is formed into a circuit by etching to complete the wiring board. No cavity is left inside the multilayer wiring board.

Procedure for manufacturing the above-mentioned base material for multilayer wiring board,
The procedure for manufacturing a multilayer wiring board using the base material for a multilayer wiring board is the same as that for manufacturing the base material for a multilayer wiring board shown in FIG. 2 and for manufacturing a multilayer wiring board using the base material for a multilayer wiring board. Applicable to

The multilayer wiring board, the substrate for a multilayer wiring board, and the method for manufacturing the same according to the present invention are not limited to the flexible printed wiring board using the polyimide film, and the flexible printed wiring board using the polyester film, The same can be applied to a rigid type using an epoxy resin, a prepreg material made of glass cloth, aramid nonwoven cloth or the like as an insulating material.

In the above, the present invention has been described in detail with respect to a specific embodiment, but the present invention is not limited to this and various modifications are possible within the scope of the technical idea of the present invention. It will be apparent to those skilled in the art that the embodiments of are possible.

[0078]

As can be understood from the above description, according to the multilayer wiring board, the multilayer wiring board substrate and the method for producing the same of the present invention, the conductive contact between the conductive layer and the conductive resin composition is penetrated. Due to the difference in diameter between the insulating base material portion of the hole and the conductive layer portion, the structure is taken on the back side of the conductive layer, which is derived from securing the contact area between the portion above the conductive layer of the conductive resin composition and the conductive layer. Free from problems, using a general-purpose copper-clad resin base material as a starting material, thin multilayer wiring without impairing the contact reliability between the conductive resin composition and the conductive circuit part, and without lowering the smoothness of the substrate. A substrate can be obtained.

Since the conductive resin composition is filled not only in the insulating base material portion and the adhesive layer portion (via hole) of the through hole but also in the conductive layer portion, after the lamination, a cavity is formed inside the multilayer wiring board. Even if a reliability test such as exposure to a high temperature is performed, problems such as peeling and peeling do not occur. In addition, the contact area between the conductive paste filled in the via hole and the conductive layer can be increased by the area of the inner peripheral surface of the conductive layer portion.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing one basic structure of a base material for a multilayer wiring board according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing another basic structure of a base material for a multilayer wiring board according to an embodiment of the present invention.

FIG. 3 is a sectional view showing a multilayer wiring board according to an embodiment of the present invention.

FIG. 4 is a sectional view showing a base material for a multilayer wiring board according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a base material for a multilayer wiring board according to another embodiment of the present invention.

6A to 6I are process diagrams showing an embodiment of a method for manufacturing a base material for a multilayer wiring board according to an embodiment of the present invention.

7 (j) to (l) are process drawings showing an embodiment of a method for manufacturing a multilayer wiring board according to an embodiment of the present invention.

FIG. 8A is an explanatory view showing a laser processed surface in a perforating step of a base material for a multilayer wiring board according to an embodiment of the present invention, and FIG. 8B is an explanatory view showing a laser intensity distribution of the same. Is.

FIG. 9 is a cross-sectional view showing an IVH structure of a conventional base material for a multilayer wiring board.

FIG. 10 is a cross-sectional view showing a defect in the IVH structure of the conventional base material for a multilayer wiring board.

FIG. 11 is a cross-sectional view showing an IVH structure in which the hole diameters of the copper foil portion and the insulating layer are the same.

FIG. 12 is a cross-sectional view showing a configuration in which a hole is not formed in a copper foil portion.

[Explanation of symbols]

10A ... Base material of the first layer 10B ... Second layer base material 11 ... Insulating resin layer 12 ... Conductive layer 13 ... Adhesive layer 14 ... Through hole 14a ... Insulating resin layer-adhesive layer portion 14b ... Conductive layer portion 15 ... Conductive resin composition 15A ... projection 16 ... Conductive layer 17 ... PET masking tape 21 ... Insulating resin layer 22 ... Conductive layer 24 ... Through hole 24a ... Insulating resin layer portion 24b ... Conductive layer portion 25 ... Conductive resin composition 25A ... Projection

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05K 3/00 H05K 3/40 K 3/40 H01L 23/12 N (72) Inventor Masahiro Okamoto Sakura, Chiba Prefecture 1440 Rokuzaki, Ichi Fujikura Co., Ltd.Sakura Works (72) Inventor Satoshi Nakao 1440, Fujikura, Sakura-shi, Chiba F-Terms inside Sakura Works, 5E317 AA24 BB03 BB11 BB25 CC22 CC25 CD32 GG14 5E346 AA02 AA12 AA15 AA16 AA41 AA43 CC10 CC31 DD02 DD12 DD32 EE02 EE06 EE07 EE42 FF03 FF18 FF24 FF35 GG02 GG15 GG16 GG28 HH07 HH24

Claims (12)

[Claims] 1. A conductive layer forming a wiring pattern is provided on one surface of an insulating base material, and a through hole penetrating the insulating base material and the conductive layer is filled with a conductive resin composition for obtaining interlayer conduction. In the base material for a multilayer wiring board, the diameter of the conductive layer portion of the through hole is smaller than the diameter of the insulating base material portion, and the conductive material is formed in all of the insulating base material portion and the conductive layer portion of the through hole. A base material for a multilayer wiring board, which is filled with a resin composition. 2. A conductive layer forming a wiring pattern is provided on one surface of an insulating base material, and an adhesive layer for interlayer adhesion is provided on the other surface of the insulating base material, and the conductive layer, the insulating base material and the adhesive layer are provided. Is a substrate for a multilayer wiring board filled with a conductive resin composition for obtaining interlayer conduction in a through hole penetrating through, wherein the diameter of the conductive layer portion of the through hole is an insulating base material portion and an adhesive layer portion. A substrate for a multilayer wiring board, which has a diameter smaller than that of the above, and in which the conductive resin composition is filled in all of the insulating base material portion, the adhesive layer portion, and the conductive layer portion of the through hole. 3. The base material for a multilayer wiring board according to claim 1, wherein the insulating base material is a flexible resin film such as polyimide. 4. The substrate for a multilayer wiring board according to claim 2, wherein the adhesive layer is made of thermoplastic polyimide or a thermoplastic polyimide having a thermosetting function. 5. The base material for a multilayer wiring board according to claim 1, wherein the conductive resin composition filled in the through holes projects toward the interlayer adhesive surface to form a projection. . 6. A multilayer wiring board including the base material for a multilayer wiring board according to claim 1. 7. A punching step of punching a through hole having a diameter of a conductive layer portion smaller than a diameter of an insulating base material portion in a laminated material in which a conductive layer forming a wiring pattern is provided on one surface of an insulating base material. A method for producing a base material for a multilayer wiring board, which comprises a filling step of filling a conductive resin composition in all of the insulating base material portion and the conductive layer portion of the through hole. 8. A laminated material having a conductive layer forming a wiring pattern on one surface of an insulating base material and an adhesive layer for interlayer adhesion on the other surface, and a conductive layer portion having an insulating base. A perforating step of perforating a through hole smaller than the diameter of the material portion and the adhesive layer portion, and a filling step of filling the conductive resin composition in all of the insulating base material portion, the adhesive layer portion and the conductive layer portion of the through hole A method for producing a base material for a multilayer wiring board, comprising: 9. The perforating step is performed by piercing a resin portion other than the conductive layer portion with a large diameter by laser beam irradiation, and after completing the perforation, the conductive layer portion is drilled with a small diameter hole to form a through hole. The method for manufacturing a base material for a multilayer wiring board according to claim 7. 10. In the perforating step, a laser beam having a laser intensity distribution in a beam diameter direction is irradiated to a surface opposite to the conductive layer, and a resin portion other than the conductive layer portion is perforated with a large diameter to make a conductive layer. The method for producing a base material for a multilayer wiring board according to claim 8 or 9, wherein holes having a small diameter are collectively formed in the layer portion to form the through holes. 11. The method for manufacturing a base material for a multilayer wiring board according to claim 9, further comprising a desmear step of removing smear generated by laser perforation after the perforation step by laser beam irradiation. 12. The base for a multilayer wiring board according to claim 6, wherein in the filling step, the conductive resin composition is filled into the through hole by squeezing from the side opposite to the conductive layer. Method of manufacturing wood.