JPH08288656A - Manufacture of multilayered printed wiring board - Google Patents

Abstract

PURPOSE: To improve wiring density and connection reliability, by forming holes for interlayer connection of circuit conductor of a plurality of inner circuits and circuit conductor of outer circuit layers on both sides, in only necessary parts. CONSTITUTION: A hole is made in a copper clad epoxy lamination board, and copper plating is performed. Etching resist is formed in the part except a wiring pattern. An inner layer board is formed by contact with etching solution. A hole is formed in the part to be connected with a penetrating hole of an inner layer circuit 11 of an insulating bonding film provided with a copper foil. The insulating bonding film provided with the copper foil in which the hole is formed is stacked on the inner layer circuit board, and collectively laminated in a unified body by heating and pressing. Copper plating 201 is performed, an outer layer circuit 21 is formed by etching and eliminating unnecessary parts of the outer copper film, and a multilayered wiring board is obtained. Thereby a constant thickness can be ensured in the part of a through hole 31 of the inner layer, and the through hole 31 can be formed only in the part necessitating connection, so that wiring density is improved and the number of circuits to be accommodated can be increased.

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 and its manufacturing method.

[0002]

2. Description of the Related Art There are many types of multilayer printed wiring boards, and various structures and manufacturing methods have been proposed and used. Also, many methods for interlayer connection of a multilayer printed wiring board have been developed, and as a typical example, (1) a plurality of single-sided circuit boards are prepared and laminated and integrated through a prepreg,
How to connect holes by making holes in the necessary parts and making the inside a conductor, (2) Creating multiple double-sided circuit boards, making holes in the parts that require connection on both sides, and making the inside a conductor, A method of laminating and integrating these through a prepreg, making a hole, connecting the inside by making it a conductor, (3) Creating an inner layer circuit board, stacking prepreg and copper foil on it, laminating and integrating, There is a method of forming a conductor inside, and finally forming an outer layer circuit, and (4) a combination of the above three methods.

[0003]

By the way, among these methods, the method (1) requires that holes are always formed in the places where the connection is required, and the wiring density is largely limited by the number of holes. And the holes restrict the wiring route,
It has become unpractical for high wiring density.
In other methods, the connection between adjacent circuit layers, or the connection between two adjacent layers is performed by providing another via hole in each adjacent layer, or as shown in FIG. A hole is made in the plate (shown in FIG. 2 (a)), and then outer layers are laminated to form a circuit as shown in FIG. 2 (b), or after lamination as shown in FIG. , They were connected by opening a hole halfway. However,
In the case of FIG. 2, two stacking steps are required, and in the case of FIG. 1, when the hole diameter is smaller than the depth of the hole, the chance of contact with the plating solution is reduced, At the bottom,
The plating thickness tends to be thin, and it may happen that the bottom is not plated at all.

An object of the present invention is to provide a multilayer wiring board excellent in wiring density and connection reliability, and a manufacturing method thereof.

[0005]

The multilayer wiring board of the present invention comprises:
It is characterized in that the circuit conductors of the plurality of inner circuit layers and the circuit conductors of the outer circuit layers on both surfaces are provided with holes for interlayer connection only at necessary portions.

In order to manufacture such a multilayer wiring board,
The following steps can be used. a. Creating an inner layer circuit board in which circuits on both sides are connected by through holes, b. A step of preparing an insulative adhesive film with a copper foil in which a semi-cured, low-fluidity insulating resin layer is formed on one surface of the copper foil, c. A step of forming a hole in a portion of the insulating adhesive film with copper foil, which is connected to a through hole of an inner layer circuit, d. A step of stacking the inner-layer circuit board and the perforated insulating adhesive film with a copper foil, and heating and pressurizing them to integrate and laminate; e. A step of plating the laminated and integrated product, f. Process of forming a circuit by etching away unnecessary parts of the outer layer copper foil,

The following manufacturing method can also be used. a. A step of forming two inner layer circuit boards in which circuits on both sides are connected by through holes, b. A step of preparing two insulative adhesive films with copper foil, which are semi-cured and have a low-fluidity insulating resin layer formed on one surface of the copper foil, c. A step of forming a hole in a portion of the insulating adhesive film with copper foil, which is connected to a through hole of an inner layer circuit, d. Between the two inner layer circuit boards, a semi-cured state,
A step of stacking an insulating adhesive film having a low-fluidity insulating resin layer formed thereon, and stacking an insulating adhesive film with a copper foil having the holes on the outside of the inner circuit board, and heating and pressing to laminate the layers. , E. A step of plating the laminated and integrated product, f. Process to form a circuit by etching away unnecessary parts of the outer copper foil

In step c, the insulating adhesive film with a copper foil may be provided with a hole at a place where it is connected to only one inner layer circuit, and an integrated laminated body is formed between steps d and e. It is also possible to provide a hole passing through.

In order to further increase the number of layers, the multilayer wiring board prepared in the above step can be used as a second inner layer circuit board, and the following steps can be performed following the above steps. g. A step of preparing a second insulating adhesive film with a copper foil, which is a semi-cured, low-flowing insulating resin layer formed on one surface of the copper foil, h. A step of forming a hole in a portion of the second insulating adhesive film with copper foil, which is connected to the through hole of the second inner layer circuit, i. A step of stacking the second inner-layer circuit board and the second insulative adhesive film with copper foil with holes and heating and pressing to laminate and integrate them; j. A step of plating the laminated and integrated product, k. Process of forming a circuit by etching away unnecessary parts of the outer layer copper foil,

Even in this case, in step h, holes are also formed in the second insulating adhesive film with copper foil at a portion to be connected to only one inner layer circuit or a portion to be connected to a through hole penetrating the inner layer circuit. Can be provided, process i and process j
It is also possible to provide a hole penetrating the integrated laminate between and.

Instead of the insulating adhesive film with copper foil, a semi-cured, low-fluidity insulating resin layer is formed on the insulating material side of a single-sided copper foil-bonded insulating substrate, and the adhesive-coated one side A copper foil-bonded insulating substrate can also be used.

The inner layer circuit board used in the present invention can be produced by a method for producing a usual wiring board, using the material used for the usual wiring board. A semi-cured, low-fluidity insulating resin layer with a copper foil on which an insulating resin layer is formed, an epoxy resin type, an acrylic modified resin type, or a polyimide resin type insulating material can be used, These can be applied to the copper foil surface by roll coating, dip coating, curtain coating, or the like. Here, the semi-cured state is 40
It is a state in which it does not have tackiness at a temperature of not higher than 0 ° C., and a strength of 0.8 kgf / cm or more can be given to the adhesive strength in the subsequent laminating adhesion. Further, the low fluidity means that the fluidity is 200 μm or less when laminated under heat and pressure at a pressure of 25 kgf / cm ² . Such an insulating adhesive film with copper foil is commercially available as MCF-3000 (manufactured by Hitachi Chemical Co., Ltd.) using a polymer epoxy resin. In addition, AS-3000 (manufactured by Hitachi Chemical Co., Ltd., trade name) using a high molecular epoxy polymer can be used as a commercially available insulating adhesive film used for forming a multilayer. The size of the holes formed in the insulating adhesive film with a copper foil of the present invention can be made larger than the through holes of the inner layer circuit board, as shown in FIG. 3 (b). In this case, it is preferable that the positional accuracy of the inner layer circuit board with respect to the through hole can be prevented from being lowered due to expansion and contraction of the material.

[0013]

In the present invention, as shown in FIG. 3, since the conductor is already formed inside the blind hole, the connection can be sufficiently performed as long as the outer layer of the hole is plated.

[0014]

【Example】

Example 1 As shown in FIG. 4 (a), a hole was formed in a copper foil-clad epoxy laminate, copper plating was performed, an etching resist was formed on a portion other than the wiring pattern, and the inner layer plate was brought into contact with an etching solution. It was created. Next, MCF-3 which is an epoxy adhesive film with copper foil shown in FIGS.
000 (manufactured by Hitachi Chemical Co., Ltd., trade name) is prepared. Next, as shown in FIG. 4 (c), holes were provided in the copper foil-insulated insulating adhesive film at locations where they were connected to the through holes of the inner layer circuit. The inner layer circuit board and the perforated insulating adhesive film with copper foil are overlaid, and the pressure is 25 kgf / c.
At m ² temperature of 170 ° C., heating and pressurization were performed for 90 minutes to laminate and integrate, and as shown in FIG. Next, copper plating was performed as shown in FIG. Next, as shown in FIG. 4 (f), unnecessary portions of the outer layer copper foil were removed by etching to form a circuit, and a multilayer wiring board was obtained.

Example 2 All were prepared in the same manner as in Example 1 except that in step c of Example 1, the insulating adhesive film with copper foil was also provided with a hole at a place where only one inner layer circuit was connected. (Not shown).

Example 3 All were prepared in the same manner as in Example 2 except that a hole was formed between the step d and the step e of Example 2 through the integrated laminate (not shown). ).

Example 4 As a double-sided copper-clad laminate, MCL-E-67 (trade name, manufactured by Hitachi Chemical Co., Ltd.), which is an epoxy resin-impregnated glass cloth copper-clad laminate, was used. After forming a hole and performing electroless plating on the entire surface, electrolytic plating is performed to form an etching resist on the surfaces of the copper foils on both sides, and unnecessary portions exposed from the etching resist are removed by etching. As shown in a), two inner layer circuit boards having circuits on both sides connected by through holes were prepared. As shown in FIG. 5B, two copper foil-containing insulating adhesive films each having a semi-cured, low-fluidity insulating resin layer formed on one surface of the copper foil were prepared. The material used at this time was the same as in Example 1. As shown in FIG. 5 (c), a hole was provided in the insulating adhesive film with copper foil at a location where it was connected to the through hole of the inner layer circuit. This hole was drilled. As shown in FIG. 5D, a polymeric epoxy is supported as an insulating adhesive film having a semi-cured and low-fluidity insulating resin layer formed between the two inner layer circuit boards. AS- which is applied to a polyethylene film which is a film and heated and dried in a semi-cured state.
3000 (manufactured by Hitachi Chemical Co., Ltd., product name) with the protective film peeled off is stacked, and on the outside of the inner layer circuit board,
The insulative adhesive film with copper foil having the holes formed thereon was stacked and heated and pressed to be laminated and integrated. As shown in FIG. 5 (e),
Electroless plating is applied to the laminated and integrated product, and the result shown in FIG.
As shown in (f), unnecessary portions of the outer copper foil were removed by etching to form a circuit.

Example 5 Instead of the insulating adhesive film with copper foil of Example 4, a semi-cured, low-fluidity insulating resin layer is formed on the insulating material side of a single-sided copper foil-clad insulating substrate. It was prepared in the same manner as in Example 1 except that the adhesive-coated one-sided copper foil-clad insulating substrate was used.

The multilayer wiring board prepared as described above is
In each case, at least the thickness of about 20 μm was secured at the location of the through hole in the inner layer. Further, since the wiring density can be provided only at the place where the connection is required, the number of circuits accommodated in the conventional multilayer wiring board can be accommodated almost twice or more. As can be seen from the above-mentioned Examples, the production efficiency was increased because the lamination pressing step was performed once for 4 layers and once for 6 layers.

[0020]

As described above, it is possible to provide a multilayer wiring board excellent in wiring density and connection reliability, and a method for efficiently manufacturing the multilayer board.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining a problem of the present invention.

FIG. 2 is a sectional view for explaining another problem of the present invention.

3A and 3B are cross-sectional views showing an embodiment of the present invention.

4A to 4G are cross-sectional views in each step for explaining the method of one embodiment of the present invention.

5 (a) to 5 (g) are cross-sectional views in each step for explaining a method of another embodiment of the present invention.

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[Procedure amendment]

[Submission date] September 19, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

[0003]

[SUMMARY OF THE INVENTION Incidentally, among these methods, (1) is the desired location of the connection, must Re only always such a hole, wiring density, larger the number of holes Is restricted, and the route of the wiring is restricted by holes,
It has become unpractical for high wiring density.
In other methods, the connection between adjacent circuit layers, or the connection between two adjacent layers is performed by providing another via hole in each adjacent layer, or as shown in FIG. A hole is made in the plate (shown in FIG. 2 ( c )), and then outer layers are laminated to form a circuit as shown in FIG. 2 ( d ), or after lamination as shown in FIG. , They were connected by opening a hole halfway. However,
In the case of FIG. 2, two stacking steps are required, and in the case of FIG. 1, when the hole diameter is smaller than the depth of the hole, the chance of contact with the plating solution is reduced, At the bottom,
The plating thickness tends to be thin, and it may happen that the bottom is not plated at all.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

Example 4 As a double-sided copper-clad laminate, MCL-E-67 (trade name, manufactured by Hitachi Chemical Co., Ltd.), which is an epoxy resin-impregnated glass cloth copper-clad laminate, was used. After forming a hole and performing electroless plating on the entire surface, electrolytic plating is performed to form an etching resist on the surfaces of the copper foils on both sides, and unnecessary portions exposed from the etching resist are removed by etching. As shown in a), two inner layer circuit boards having circuits on both sides connected by through holes were prepared. As shown in FIG. 5B, two copper foil-containing insulating adhesive films each having a semi-cured, low-fluidity insulating resin layer formed on one surface of the copper foil were prepared. The material used at this time was the same as in Example 1. As shown in FIG. 5 (c), a hole was provided in the insulating adhesive film with copper foil at a location where it was connected to the through hole of the inner layer circuit. This hole was drilled. As shown in FIG. 5D, a polymeric epoxy is supported as an insulating adhesive film having a semi-cured and low-fluidity insulating resin layer formed between the two inner layer circuit boards. Polyethylene teref, which is a film
The protective film of AS-3000 (manufactured by Hitachi Chemical Co., Ltd., which is a product of Hitachi Chemical Co., Ltd.), which is applied to a tarate film and dried by heating in a semi-cured state, is peeled off, and the holes are formed on the outside of the inner circuit board. The insulative adhesive film with copper foil having been opened was stacked and heated and pressed to be laminated and integrated.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazuhisa Otsuka 1500 Ogawa, Shimodate City, Ibaraki Prefecture Hitachi Chemical Co., Ltd. Shimodate Research Center

Claims (12)

[Claims] 1. A multilayer wiring board characterized in that a plurality of circuit conductors of an inner circuit layer and circuit conductors of outer circuit layers on both surfaces are interlayer-connected only at a necessary position. 2. A method for manufacturing a multilayer wiring board, comprising the following steps. a. Creating an inner layer circuit board in which circuits on both sides are connected by through holes, b. A step of preparing an insulative adhesive film with a copper foil in which a semi-cured, low-fluidity insulating resin layer is formed on one surface of the copper foil, c. A step of forming a hole in a portion of the insulating adhesive film with copper foil, which is connected to a through hole of an inner layer circuit, d. A step of stacking the inner-layer circuit board and the perforated insulating adhesive film with a copper foil, and heating and pressurizing them to integrate and laminate; e. A step of plating the laminated and integrated product, f. Process of forming a circuit by etching away unnecessary parts of the outer layer copper foil, 3. A method for manufacturing a multilayer wiring board, comprising the following steps. a. A step of forming two inner layer circuit boards in which circuits on both sides are connected by through holes, b. A step of preparing two insulative adhesive films with copper foil, which are semi-cured and have a low-fluidity insulating resin layer formed on one surface of the copper foil, c. A step of forming a hole in a portion of the insulating adhesive film with copper foil, which is connected to a through hole of an inner layer circuit, d. Between the two inner layer circuit boards, a semi-cured state,
A step of stacking an insulating adhesive film having a low-fluidity insulating resin layer formed thereon, and stacking an insulating adhesive film with a copper foil having the holes on the outside of the inner circuit board, and heating and pressing to laminate the layers. , E. A step of plating the laminated and integrated product, f. Process of forming a circuit by etching away unnecessary parts of the outer layer copper foil, 4. The process for producing a multilayer wiring board according to claim 2, wherein in step c, the insulating adhesive film with a copper foil is provided with a hole at a place where only one inner layer circuit is connected. Law. 5. A hole for penetrating the integrated laminated body is provided between step d and step e.
A method for manufacturing a multilayer wiring board according to any one of 1. 6. A method of manufacturing a multilayer wiring board, comprising the following steps. a. Creating an inner layer circuit board in which circuits on both sides are connected by through holes, b. A step of preparing an insulative adhesive film with a copper foil in which a semi-cured, low-fluidity insulating resin layer is formed on one surface of the copper foil, c. A step of forming a hole in a portion of the insulating adhesive film with copper foil, which is connected to a through hole of an inner layer circuit, d. A step of stacking the inner-layer circuit board and the perforated insulating adhesive film with a copper foil, and heating and pressurizing them to integrate and laminate; e. A step of plating the laminated and integrated product, f. A step of forming a circuit by etching away unnecessary portions of the outer layer copper foil to form a second inner layer circuit board; g. A step of preparing a second insulating adhesive film with a copper foil, which is a semi-cured, low-flowing insulating resin layer formed on one surface of the copper foil, h. A step of forming a hole in a portion of the second insulating adhesive film with copper foil, which is connected to the through hole of the second inner layer circuit, i. A step of stacking the second inner-layer circuit board and the second insulating adhesive film with a copper foil with holes and heating and pressurizing to integrate the layers; j. A step of plating the laminated and integrated product, k. Process of forming a circuit by etching away unnecessary parts of the outer layer copper foil, 7. A method for manufacturing a multilayer wiring board, comprising the following steps. a. A step of forming two inner layer circuit boards in which circuits on both sides are connected by through holes, b. A step of preparing two insulative adhesive films with copper foil, which are semi-cured and have a low-fluidity insulating resin layer formed on one surface of the copper foil, c. A step of forming a hole in a portion of the insulating adhesive film with copper foil, which is connected to a through hole of an inner layer circuit, d. Between the two inner layer circuit boards, a semi-cured state,
A step of stacking an insulating adhesive film having a low-fluidity insulating resin layer formed thereon, and stacking an insulating adhesive film with a copper foil having the holes on the outside of the inner circuit board, and heating and pressing to laminate the layers. , E. A step of plating the laminated and integrated product, f. Remove unnecessary parts of the outer copper foil by etching
Creating an inner layer circuit board of g. A step of preparing a second insulating adhesive film with a copper foil, which is a semi-cured, low-flowing insulating resin layer formed on one surface of the copper foil, h. A step of forming a hole in a portion of the second insulating adhesive film with copper foil, which is connected to the through hole of the second inner layer circuit, i. A step of stacking the second inner-layer circuit board and the second insulating adhesive film with a copper foil with holes and heating and pressurizing to integrate the layers; j. A step of plating the laminated and integrated product, k. Process of forming a circuit by etching away unnecessary parts of the outer layer copper foil, 8. The process for producing a multilayer wiring board according to claim 6, wherein in step c, the insulating adhesive film with a copper foil is provided with a hole at a place where only one inner layer circuit is connected. Law. 9. The method according to claim 6, wherein a hole passing through the integrated laminated body is provided between step d and step e.
A method for manufacturing a multilayer wiring board according to any one of 1. 10. In step h, a portion of the second insulating adhesive film with copper foil, which is connected to only one inner layer circuit,
Alternatively, the method for manufacturing a multilayer wiring board according to any one of claims 6 to 9, wherein a hole is also provided at a position connected to a through hole penetrating the inner layer circuit. 11. The method according to claim 6, wherein a hole is provided between the step i and the step j so as to pass through the integrated laminated body.
11. The method for manufacturing a multilayer wiring board according to any one of 10. 12. An insulating adhesive film with a copper foil is replaced with
3. A one-sided copper-clad insulating substrate with an adhesive, in which a semi-cured, low-fluidity insulating resin layer is formed on the insulating material side of the one-sided copper-clad laminated insulating substrate.
11. The method for manufacturing a multilayer wiring board according to any one of 1 to 11.