JPH11204896A - Printed wiring board with flexible part and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring board which is simplified in structure and manufactured through a simple manufacturing process at a low cost without using an expensive sheet material such as an overlay film, a bonding sheet or prepreg. SOLUTION: A printed wiring board is equipped with a flexible part B, a rigid part A is formed on a part of the flexible board where a wiring pattern is formed, a protective layer formed on the prescribed part B of the printed board and the rigid part A formed by hardening a non-conductive adhesive agent layer 6 and provided to a part of the flexible board are provided.

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 having a flexible portion formed by forming a rigid portion on a part of a flexible wiring board having flexibility and a method of manufacturing the same.

[0002]

2. Description of the Related Art A printed wiring board having a flexible portion is obtained by laminating a rigid substrate such as a glass substrate or an epoxy resin substrate on a part of a flexible substrate having a wiring pattern formed on the surface of a flexible insulating substrate. By utilizing the flexibility of the flexible portion, it is folded and incorporated into an electronic device such as a personal computer or a mobile phone, so that it is possible to effectively utilize a space and to cope with a reduction in size and thickness.

FIG. 5 shows a conventional example of a printed wiring board having the above-mentioned flexible portion, and is a longitudinal sectional view for explaining the structure thereof.

1, a printed wiring board 1 is made of a flexible insulating film 2 such as a polyimide film.
Flexible substrate 4 having a wiring pattern 3 formed on the surface thereof
And a rigid wiring board 10 laminated on both ends of the flexible substrate 4 via an adhesive sheet such as a bonding sheet or a prepreg.

The rigid wiring board 10 has a wiring pattern 7 on a surface of a rigid substrate such as a glass substrate or an epoxy resin substrate.
In a rigid portion A on which the rigid wiring board 10 is laminated, a through-hole 11 having a conductive thin film 11a formed on the inner peripheral surface of the hole is formed so as to penetrate therethrough. The flexible portion B having flexibility includes a rigid portion A,
A is formed between A.

The surface of the flexible wiring board 4 on which the wiring pattern 3 is formed is covered with a cover lay film for protecting the wiring pattern 3, and the surface thereof is further covered with an adhesive layer 5 such as a bonding sheet, prepreg, epoxy resin or the like.
Is formed and the rigid wiring board 10 is bonded.

[0007]

However, in the above-mentioned conventional printed wiring board having a flexible portion, the protective layer made of the coverlay film is formed by laminating or hot-rolling before the rigid wiring board 10 is bonded. It is necessary to form them, which causes a problem that the manufacturing process becomes complicated and the cost increases.

Further, an adhesive layer 5 such as a bonding sheet or a prepreg, which is adhered to the flexible wiring board 4.
Of these, it is necessary to remove the adhesive layer 5 at the portion that becomes the flexible portion B, but there is a problem that removing the adhesive layer 5 is troublesome and the production cost is increased.

Further, since a sheet-like material such as a coverlay film, a bonding sheet or a prepreg is used, the cost for manufacturing the sheet is high and the manufacturing cost for the printed wiring board is high. .

The present invention has been made in view of the above problems, and simplifies the structure and manufacturing process of a printed wiring board without using expensive sheet-like materials such as a coverlay film, a bonding sheet, and a prepreg. An object of the present invention is to provide a printed wiring board having a flexible portion and a method of manufacturing the same, which can reduce the manufacturing cost.

[0011]

According to a first aspect of the present invention, there is provided a printed wiring board having a flexible portion, wherein a rigid portion is formed on a part of a flexible substrate on which a wiring pattern is formed. In a printed wiring board having a flexible portion, a protective layer formed at a predetermined portion serving as a flexible portion of the printed wiring board, of a portion where a wiring pattern of the flexible substrate is formed, and the part of the flexible substrate And a rigid portion formed by curing a non-conductive adhesive layer.

With this configuration, it is not necessary to form a protective layer using a sheet material such as a coverlay film, and it is not necessary to bond a rigid substrate such as a glass substrate or an epoxy resin, thereby simplifying the configuration of the printed wiring board. It can be something.

According to a second aspect of the present invention, there is provided a printed wiring board having a flexible portion, wherein a wiring pattern made of a conductive film is formed on one surface of the adhesive layer.

With this configuration, the conductive film such as a copper foil is directly bonded to the flexible substrate by the adhesive layer.
The configuration of the printed wiring board can be simplified.

In the rigid portion formed by the adhesive layer, a drilling operation of a through hole by a drill is easy, a crack is hardly generated, and a high quality printed wiring board can be obtained.

According to a third aspect of the present invention, in the printed wiring board, the adhesive layer is formed of a resin mainly composed of an epoxy resin.

Since a resin containing an epoxy resin as a main component is excellent in adhesiveness and non-conductivity and is inexpensive, it is possible to manufacture a high quality printed wiring board at low cost.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a printed wiring board having a flexible portion in which a rigid portion is formed on a part of a flexible substrate on which a wiring pattern is formed. Forming a wiring pattern on the flexible substrate, and applying a liquid cover coating agent to a predetermined portion of the portion of the flexible substrate on which the wiring pattern is formed to be a flexible portion of the printed wiring board to protect the portion. Forming a layer, and applying an adhesive to a part of the flexible substrate, and curing the adhesive to form a rigid portion formed of an adhesive layer, characterized by this configuration, Coverlay sheet to protect the wiring pattern of the flexible board, or rigid board by laminating press etc. The step of bonding is not required, and the manufacturing process can be simplified to greatly reduce the manufacturing cost.

According to a fifth aspect of the present invention, in the method of manufacturing a printed wiring board having a flexible portion, a conductive film having an adhesive layer formed on one surface is adhered to a part of the flexible substrate, and the adhesive is cured. Forming a rigid portion made of an adhesive layer, and forming a wiring pattern on the conductive film, by this method, a conductive film such as a copper foil is directly formed on a flexible substrate together with the formation of the adhesive layer. Adhesion can be performed, so that the manufacturing process of the printed wiring board can be simplified and the manufacturing cost can be reduced.

According to a sixth aspect of the present invention, in the method of manufacturing a printed wiring board, the adhesive layer is formed of a resin mainly composed of an epoxy resin.

A resin containing an epoxy resin as a main component is excellent in adhesiveness and non-conductivity and is inexpensive, so that a high quality printed wiring board can be manufactured at low cost.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a printed wiring board having a flexible portion according to the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view for explaining the structure of one embodiment of the multilayer printed wiring board according to the present invention.

As shown in the figure, a flexible wiring board 4 constituting a printed wiring board 1 has a wiring pattern 3 formed on the surface of a flexible film 2 such as a polyimide film. At both ends of the flexible wiring board 4, an adhesive layer 6 formed by applying and curing a non-conductive resin mainly composed of an epoxy-based resin is formed, and forms a rigid portion A.

A wiring pattern 7 made of a conductive film such as a copper foil is formed on the surface of the adhesive layer 6. Further, a through hole 8 is formed in the adhesive layer 6 so as to penetrate from one side where the wiring pattern 7 is formed to the other side. A conductive thin film is formed on the inner peripheral surface of the through hole 8 by plating or the like.

Flexible part B between rigid parts A, A
, A liquid cover coating material 9 is applied to one surface of the flexible wiring board 4 on which the wiring pattern 3 is formed. This cover coat material 9 is cured after being applied,
This protects the wiring pattern 3.

Next, one embodiment of the method for manufacturing a printed wiring board according to the present invention will be described with reference to FIGS.

FIG. 2 is a flow chart for explaining a method for manufacturing a printed wiring board according to the present invention, and FIG. 3 is an explanatory view for explaining a method for manufacturing a printed wiring board according to the present invention. FIG. 4 is a perspective view showing a state in which a liquid cover coating material is applied, and FIG. 4 is a view for explaining a step of bonding a copper foil having a non-conductive adhesive layer formed on one surface by a hot roll method.

First, the wiring pattern 3 is formed on the flexible wiring board 4 serving as an inner layer (step S1).

A liquid cover coat material 9 for protecting the wiring pattern 3 is applied to the surface of the flexible wiring board 4 on which the wiring pattern 3 is formed (step S2).

After the liquid cover coat material 9 is cured,
The copper foil 8 having the non-conductive adhesive layer 6 formed on one surface of the flexible wiring board 4 is bonded by a hot roll method or the like (step S3). An epoxy resin or the like is suitable for the adhesive layer.

After the adhesive layer is cured, the through holes 11
Is formed and plating 11a is performed on the inner peripheral surface of the through hole 11, and a wiring pattern 7 is formed on the copper foil 8 (step S4).

Thereafter, a protective layer is formed on the wiring pattern 7 as necessary, and external processing, inspection, and the like are performed.

The printed wiring board 1 manufactured by the above-described process does not use a sheet material as a protective layer of the wiring pattern 3 and adheres a glass substrate or the like to the laminated portion of the rigid portion A. As a result, the manufacturing process is simplified, and the manufacturing cost can be greatly reduced. In addition, the printed wiring board manufactured by this manufacturing method had equivalent or better electrical characteristics and workability than those of the conventional configuration.

Although the preferred embodiment of the present invention has been described, the wiring patterns 3, 7 formed on the rigid portion A and the flexible portion B are not limited to the copper foil 8, but may be formed of another conductive film, for example, an aluminum foil. There may be. The adhesive layer 6 is not limited to a resin containing an epoxy resin as a main component, but may be another resin as long as it is nonconductive, has adhesiveness, and has a certain degree of hardness after curing.

[0036]

According to the printed wiring board having a flexible portion of the present invention, it is not necessary to form a protective layer with a sheet material such as a coverlay film, and a conductive film such as a copper foil is formed by an adhesive layer. By directly adhering to the flexible substrate, the configuration of the printed wiring board can be simplified. Further, in the rigid portion formed by the adhesive layer, a drilling operation of a through hole by a drill is easy, a crack is hardly generated, and a high quality printed wiring board can be obtained.

In particular, if a resin mainly composed of an epoxy resin is used as the adhesive layer, a high quality printed wiring board can be provided at a lower cost.

According to the method of manufacturing a printed wiring board of the present invention, a step of bonding a coverlay sheet for protecting a wiring pattern of a flexible substrate or a rigid substrate such as a glass substrate or an epoxy substrate by a lamination press or the like. Is not required, and the manufacturing process can be simplified to greatly reduce the manufacturing cost. In addition, a conductive film such as a copper foil can be directly bonded to the flexible substrate together with the formation of the adhesive layer, so that the manufacturing process can be omitted and the manufacturing cost can be further reduced. Furthermore, if a resin containing an epoxy resin as a main component is used as the adhesive layer, a high-quality printed wiring board can be provided at lower cost.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view illustrating a structure of a printed wiring board according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a method for manufacturing a printed wiring board according to the present invention.

FIG. 3 is an explanatory view of the method for manufacturing a printed wiring board of the present invention, and is a perspective view showing a state in which a liquid cover coating material is applied to a surface of a flexible wiring board on which a wiring pattern is formed.

FIG. 4 is a view illustrating a step of bonding a copper foil having a non-conductive adhesive layer formed on one surface thereof by a hot roll method.

FIG. 5 is a longitudinal sectional view illustrating a conventional example of a printed wiring board having a flexible portion, and illustrating the structure thereof.

[Explanation of symbols]

 Reference Signs List A rigid part B flexible part 1, 1 'printed wiring board 2 insulating film 3 wiring pattern 4 flexible wiring board 5, 6 adhesive layer 7 wiring pattern 8 copper foil 9 cover coating material 10 rigid wiring board 11 through hole

Claims (6)

[Claims] 1. A printed wiring board having a flexible portion formed by forming a rigid portion on a part of a flexible substrate on which a wiring pattern is formed, wherein the printed portion of the portion of the flexible substrate on which the wiring pattern is formed is formed. A protective layer formed on a predetermined portion to be a flexible portion of the wiring board; and a rigid portion formed on the part of the flexible substrate and cured by a non-conductive adhesive layer. Printed wiring board having a flexible portion. 2. The printed wiring board according to claim 1, wherein a wiring pattern made of a conductive film is formed on one surface of the adhesive layer. 3. The printed wiring board according to claim 1, wherein the adhesive layer is formed of a resin mainly composed of an epoxy resin. 4. A method for manufacturing a printed wiring board having a flexible portion formed by forming a rigid portion on a part of a flexible substrate on which a wiring pattern is formed, wherein: a step of forming a wiring pattern on the flexible substrate; A step of applying a liquid cover coating agent to a predetermined portion of the flexible printed circuit board where the wiring pattern is formed to be a flexible portion to form a protective layer; Forming a rigid part comprising an adhesive layer by applying the adhesive to the part and curing the adhesive. A method for producing a printed wiring board having a flexible part, comprising: 5. A part of the flexible substrate is bonded with a conductive film having an adhesive layer formed on one surface thereof, and the adhesive is cured to form a rigid portion formed of the adhesive layer. The method for manufacturing a printed wiring board having a flexible part according to claim 4, wherein a wiring pattern is formed on the conductive film. 6. The method according to claim 4, wherein the adhesive layer is a resin mainly composed of an epoxy resin.