JPH0837381A - Manufacture of multilayered wiring board with terminal - Google Patents

Abstract

PURPOSE:To manufacture a multilayered wiring board with terminal with high workability and efficiency by cutting off the unnecessary part of an inner-layer wiring forming material from the line of a non-adhesive mold releasing film after the material and adhesive metallic foil are piled up upon another and stuck to each other with the inner-layer wiring material and mold releasing film in between. CONSTITUTION:Adhesive metallic foil which is formed by sticking metallic foil to an adhesive resin layer and through which a hole is formed is put on an inner-layer wiring forming material with a non-adhesive mold releasing film in between (Fig. a). Then the inner-layer wiring forming material and metallic foil are stuck to each other with the inner-layer wiring forming material and metallic foil in between (Fig. b) and wiring is formed in the laminated body (Figs. c-e). Then the end sections of the inner-layer wiring forming material are cut off along the external size of a multilayered wiring board (Fig. g). Therefore, the connection between wiring boards and between wiring boards and electronic parts can be easily made through fewer processes without using any expensive material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a high-density multilayer wiring board with terminals.

[0002]

2. Description of the Related Art As electronic devices become lighter, thinner, shorter, smaller, and more sophisticated, the installation space for wiring boards is becoming narrower, and wiring boards are required to have higher density and thinner thickness. Light, thin, short, and small multilayer wiring boards are increasingly installed in different shapes according to the size of the installation space.

As a method therefor, a method using a rigid multi-layered wiring board having an irregular shape suitable for the shape of the space, a method using a composite wiring board in which a plurality of rigid multi-layered wiring boards are mechanically connected by a flexible wiring board, and a rigid wiring board are used. There has been a method of using a rigid flex wiring board in which a flexible wiring board is extended in a multilayer wiring board portion.

[0004]

In the case of the method of the invention, since the multilayer wiring board is irregular, the wiring board after laminating and adhering is poor in board removal, resulting in low material yield and high wiring board cost. There is.

In the case of the method (1), since the wiring board is formed in a shape with a good material yield (generally rectangular), the yield problem can be solved. However, the cost of the flexible wiring board used only for connection is high, and it is necessary to connect both ends of the flexible wiring board that has been made as small as possible in order to minimize the cost increase to the rigid wiring board.
There is a problem of poor workability.

In the case of (1), the material used for the conventional rigid flex wiring board is expensive, and since the lamination bonding is performed in the final shape, the material yield is low and the cost becomes higher and higher as in (1). There is a problem.

An object of the present invention is to provide a method of manufacturing a multilayer wiring board with terminals which is excellent in workability and is efficient.

[0008]

As shown in FIG. 1 (a), a method for manufacturing a multilayer wiring board with a terminal according to the present invention integrates an inner layer wiring formation, a metal foil and an adhesive resin layer. An adhesive metal foil having holes formed in advance is laminated and adhered (shown in FIG. 1 (b)) by laminating a release film which is non-adhesive with the inner layer wiring formed product at the end portion, and is laminated. 1 (c) to (e). Then, as shown in FIG. 1 (f), the outer shape is cut, and the release film is formed as shown in FIG. 1 (g). It is characterized in that the end portion of the inner layer wiring formed product is cut and removed with the boundary defined as.

For making holes in the adhesive metal foil, known methods such as drilling and punching can be used.

The type of resin used in the resin layer of the adhesive metal foil is not particularly limited, but epoxy resin, phenol resin and modified resins thereof are particularly suitable. Epoxy resin, which has comprehensively excellent properties such as heat resistance, mechanical properties, electrical properties, and chemical resistance, is suitable for multilayer wiring boards with terminals that require high properties. Although the characteristics are slightly lowered, the resin is inexpensive and the phenol resin, which is often used for wiring board applications, is suitable for a low-cost multilayer wiring board with terminals. The resin layer may contain an organic or inorganic filler. In addition, the inclusion of paper, woven fabric or non-woven fabric in the resin layer is not limited.

When the resin used for the resin layer has too low a viscosity during heating, the interlayer insulation becomes insufficient, and particularly in the case of the method described in claim 3, the resin is not formed in the hole for IVH connection described later. There is a problem such as exudation, which makes it impossible to establish continuity. In order to maintain the viscosity appropriately, a method of adjusting the apparent viscosity by adding a filler as described above or using paper, woven fabric, or non-woven fabric to reduce the proportion of the resin contained in the resin layer is used. May be.

The terminal portion of the multilayer wiring board with terminals of the present invention is
Although it is not required to have a bending resistance as high as that of a general flexible wiring board, it is required to have a degree of flexibility such that cracks do not occur when it is bent to some extent. In the case of general epoxy resin and phenol resin, if they are made into a film and cured, they are easily cracked. Therefore, it is necessary to mix the flexibilizer and modify the resin. At this time, it is necessary to secure the heat resistance and electrical characteristics of the resin, and it is desirable that the resin be less expensive than the polyimide resin.

When a high molecular weight epoxy resin is used as the resin of the adhesive metal foil, it retains a certain degree of flexibility after curing without being flexibilized or modified, and also has a resin viscosity during heating during lamination and adhesion. Can be kept high and is suitable for the purpose of the present invention. AS3000 (trade name, manufactured by Hitachi Chemical Co., Ltd.) can be used as the high molecular weight epoxy resin.

According to the present invention, the resin layer of the adhesive metal foil is formed of a plurality of resins in a multi-layer structure, and in that case, the resin layers other than the outermost layer have no adhesive force (for example, cured). Does not exclude including.

A relatively heat resistant resin film such as a polyester film or a polyimide film can be used as the release film which is inserted for the purpose of preventing the adhesion between the inner layer wiring formed product and the adhesive metal foil at the time of lamination and adhesion. . If the thickness of these release films is too thick, a step becomes large at the time of laminating and bonding, and the laminating and bonding becomes incomplete. If it is too thin, it will be difficult to handle. From these facts, the thickness is preferably 15 to 80 μm, more preferably 30 μm.
~ 60 microns.

For laminating and bonding, a usual method of arranging a desired laminate between the mirror plates can be used, but if the resin layer of the adhesive metal foil is not sufficiently embedded in the gap portion of the inner layer wiring. In many cases, the peripheral portion of the release film is poorly adhered due to the unevenness or the step of the release film.

In order to prevent this, it is desirable to insert a cushion material between the end plate and the laminate. As the cushion material, one having flexibility such as silicone rubber and one having increased flexibility at the temperature at the time of laminating and bonding such as polyethylene film can be used.

The thickness of the cushion material should be such that a cushioning effect can be obtained. If the cushion material is unnecessarily thick, not only the cost of the cushion material increases but also the heat transfer from the hot plate to the laminate is achieved. There is a problem of getting worse. From these things, the thickness is preferably 30 microns to 2 mm. In particular, in the case of a thermoplastic resin film such as a polyethylene film that has a large viscosity decrease at the temperature during lamination and adhesion,
100 microns is sufficient, more preferably 30
~ 60 microns.

In a step after the laminating adhesion, the end portion of the inner layer wiring formed product is cut and removed with the release film as a boundary. The timing of this cutting and removal is not particularly limited, but it is desirable to carry out after the outer shape processing. For the cutting, V cutting may be performed in advance on the cut portion of the inner layer wiring formed product, or V cutting may be performed after stacking and the end portion may be broken off at the V cutting portion. Further, it is also possible to cut by cutting with a knife to a certain depth from the unnecessary portion side (the back surface side of the terminal formation surface). When connecting terminals are provided on both sides, if the inner layer wiring board is V-cut in advance, unnecessary portions can be easily folded off after the outer shape processing. There are various other embodiments of the cutting method.

The release film is preferably left for strengthening the terminal portion. Depending on this purpose, it is necessary to select a release film and surface treatment (corona treatment, etc.). A conventional through-hole connection can be used for the connection between the wiring layers. Further, as described in claim 3, if an adhesive metal foil that is preliminarily punched is used, IVH (interstitial via hole) connection can be performed simultaneously with through hole connection. As a connecting method, a method of connecting by plating can be used, but in addition, a method of filling and connecting a conductive material such as a copper paste or a silver paste can also be used.

[0021]

In the present invention, at least a release film that is non-adhesive to the inner layer wiring formed product is interposed, and after the layers are bonded together, unnecessary portions of the inner layer wiring formed product are cut and removed with the release film as a boundary. Therefore, at the time of lamination adhesion, it can be handled and produced in the same manner as a general multilayer wiring board, and since the release film is at least non-adhesive to the inner layer wiring formed product, a method such as making a notch Thus, the inner layer wiring formed product can be easily cut and removed from the end portion.

In addition, according to the present invention, when a resin having a high viscosity is used, it is difficult to sufficiently fill the gap between the inner layer wirings and the step due to the release film with the resin by a normal press using an end plate, and a void is generated. Or, it may cause cracks during the thermal cycle. In the present invention, such a problem is solved by inserting a cushioning material between the end plate and the one to be laminated.

As described above, the unnecessary portion of the substrate can be easily cut and removed, and by using this portion as the connection terminal,
Can be connected to other wiring boards and electronic components. As a result, a wiring board with connection terminals can be manufactured at substantially the same cost as a conventional multilayer wiring board. Even when wiring boards are installed in a narrow space, a plurality of wiring boards are installed and the wiring boards with connection terminals of the present invention are used to connect the necessary wiring boards to each other, thereby making it possible to achieve high-density equipment. Can be achieved at low cost.

[0024]

【Example】

(Preparation of Inner-Layer Wiring Formed Product) An inner-layer wiring was formed by etching, in which a core was formed by laminating copper foils on both sides of a base material impregnated with epoxy resin on a glass cloth, and lands were provided at necessary portions of the IVH connection portion. (Preparation of adhesive metal foil with holes) Epoxy resin film AS3000 having a thickness of 50 microns (manufactured by Hitachi Chemical Co., Ltd.,
The product name) and the copper foil were superposed and heated under pressure to bond them.
The bonding at this time was performed in a short time (about 5 minutes) so that the epoxy adhesive film B stage state was maintained. An adhesive metal foil with holes was prepared by drilling a hole (0.3 mm diameter) for IVH connection in this adhesive metal foil (copper foil).

Example A polyester film for mold release is arranged at the end portion of the wiring board of the inner layer wiring formed product, and a small amount of adhesive is used at the portion (cutting margin) not finally becoming the wiring board. I tentatively stopped. An adhesive metal foil with holes was placed on this product and laminated and adhered. Next, a hole was drilled for connecting the through hole with a drill. After performing processing such as hole cleaning, thick copper plating for interlayer connection was performed at the through hole connecting portion and the IVH connecting portion. After that, the surface wiring and the terminals for connection were formed at the ends by a tenting method.
After performing V-cut processing on the end portion of the substrate, outer shape cutting processing was performed, and the end portion of the inner layer wiring formed product was cut and removed from the V-cut portion. After the solder resist was formed and the components were mounted on the thus-prepared wiring board with terminals, the wiring board was connected to another wiring board at the terminal portion by soldering.

[0026]

According to the present invention, it is possible to easily connect the wiring boards to each other and to connect the wiring boards and the electronic components with a small number of steps without using an expensive material. Further, IVH connection is possible, and it can be used for applications requiring high density, and the cost increase at this time is smaller than that of the conventional method. As described above, the present invention contributes to high density electronic devices at low cost.

[Brief description of drawings]

1A to 1G are cross-sectional views of each step showing an embodiment of the present invention.

FIG. 2 is a top view for explaining an embodiment of the present invention.

FIG. 3 is a top view showing an embodiment of the present invention.

FIG. 4 is a sectional view showing a usage state of an embodiment of the present invention.

FIG. 5 is a cross-sectional view for explaining a usage state of an embodiment of the present invention.

FIG. 6 is a sectional view showing another embodiment of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H05K 1/11 C 7511-4E (72) Inventor Kazuhisa Otsuka 1500 Ogawa, Shimodate City, Ibaraki Hitachi Chemical Shimodate Research Laboratory, Industrial Co., Ltd. (72) Akinari Kida, 1500 Ogawa, Shimodate City, Ibaraki Prefecture Hitachi Chemical Co., Ltd. Shimodate Research Laboratory, Yoshihiro Tamura, 1500, Ogawa, Shimodate City, Ibaraki Hitachi Chemical Co., Ltd. in the factory

Claims (6)

[Claims] 1. A mold release which is non-adhesive to at least the inner layer wiring formed product at the end, the inner layer wiring formed product and an adhesive metal foil in which a metal foil and an adhesive resin layer are integrated and pre-punched. With terminals, characterized by laminating and interposing a film, forming wiring on the laminated adhesive, cutting the outer shape, and cutting and removing the end of the inner layer wiring formation with the release film as the boundary. Manufacturing method of multilayer wiring board. 2. The terminal according to claim 1, wherein the inner layer wiring formed product is an inner layer wiring formed product in which the inner layer wiring is formed on a substrate mainly composed of glass cloth and a thermosetting resin. Manufacturing method of multilayer wiring board. 3. A multilayer wiring board with a terminal according to claim 1, wherein a cushioning material is inserted between the end plate and the laminate to laminate and bond the layers. Manufacturing method. 4. The method for manufacturing a multilayer wiring board with a terminal according to claim 1, wherein the adhesive resin layer is a resin layer mainly containing an epoxy resin. 5. The method for manufacturing a multilayer wiring board with terminals according to claim 4, wherein the resin of the resin layer containing epoxy resin as a main component is a resin containing high molecular weight epoxy resin as a main component. 6. The method for producing a multilayer wiring board with a terminal according to claim 1, wherein the adhesive resin layer is a resin layer containing a phenol resin as a main component.