JPH06204663A - Manufacture of printed wiring board - Google Patents

Abstract

PURPOSE:To easily obtain a high-reliability rigid-flexible type printed wiring board without using complicated processes and special facilities and skills. CONSTITUTION:In laminating and arranging a hard type printed wiring board 5 on the surface of a flexible wiring board 8, a non-adhesive piece 6 corresponding to a region where an insulating adhesive layer 7 does not intervene is adhered and disposed on the surface of the flexible wiring board 8 or the surface of the hard type printed wiring board 5.

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 printed wiring board, and more particularly to a method for manufacturing a bendable printed wiring board composed of a hard printed wiring unit and a flexible portion.

[0002]

2. Description of the Related Art Conventionally, the following structure has been adopted as a circuit structure that also serves as a wiring connection portion and a device casing which are required to have flexibility, or as a laminated or compact structure of wiring or circuit units. Printed wiring boards are known. For example, as shown in the cross-sectional view of the main part configuration in FIG. 4, the flexible wiring board 1 forming the above-mentioned separated portion is formed by laminating hard printed wiring board units 2 and 2'on a surface of the flexible wiring board 1 with appropriate separation. There is known a printed wiring board configured to be bendable according to ′. In FIG. 4, reference numeral 1a is a wiring conductor of the flexible wiring board 1, and 2a and 2a '.
Is the wiring conductor of the rigid printed wiring board units 2 and 2 ',
Reference numerals 3 respectively indicate through-hole connections.

A printed wiring board of this type is generally manufactured as follows. 5 to 7 schematically show the embodiments in the order of manufacturing steps. First, as shown in a sectional view in FIG. 5, a required flexible wiring board 1 prepared in advance and one main surface are provided. A required wiring conductor (wiring pattern) 2a is formed, an outer layer circuit forming copper foil 2b is adhered to the other main surface, and a circuit forming region (corresponding to the hard printed wiring board unit 2, 2 ') and non- A hard printed wiring board in which a groove 2c for cutting is formed on the surface on which the wiring conductor (wiring pattern) 2a is formed so as to enable cutting / separation of the circuit forming region 2 ″, and an insulating adhesive sheet with a window 4a. Positioning, stacking, and arranging 4. Here,
The window 4a of the insulating adhesive sheet 4 corresponds to the non-circuit forming area 2 "of the hard printed wiring board.

Next, the laminated body having the above positioning, arrangement and lamination is subjected to pressure and heat treatment to be integrated, and then the outer layer circuit forming copper foil 2b forming a surface layer is subjected to so-called photo-etching treatment. While forming the required outer layer circuit, through hole processing is performed. After that, after the outer shape is processed along the so-called outer shape processing line, the circuit forming area (in other words, the hard printed wiring board units 2 and 2 ') and the non-circuit forming area 2 "can be cut and separated. By forming a groove corresponding to the separation groove 2c on the outside of the hard printed wiring board and selectively separating and separating the non-circuit forming region 2 ″, the structure as shown in FIG. A foldable printed wiring board can be obtained.

[0005]

However, in the method of manufacturing a printed wiring board having the above-described structure, the steps are complicated and the productivity is inferior. That is, when laminated and integrated by pressurization and heat treatment, as shown in a sectional view of a main part in FIG. 6, it is originally desired that the peeling / separation can be performed as easily as possible. A phenomenon in which a part of the insulating adhesive sheet 4 melted flows out to the circuit forming region 2 ″ and the non-circuit forming region 2 ″ is bonded and integrated with the surface of the flexible wiring board 1 is observed. For this reason, it becomes difficult to selectively separate and peel off the non-circuit forming region 2 ″ in the final step, and as a result, the foldable flexible area is shortened compared to the design value, or the rigid printed wiring board unit There is a problem in that the separation surface between the non-circuit forming area 2 ″ and the non-circuit forming area 2 ″ is likely to be uneven as shown in FIG. That is, it is practically difficult to obtain a printed wiring board in which the flexible wiring board 1 ′ area and the hard printed wiring board units 2 and 2 ′ areas are arranged and integrated with a predetermined size and accuracy and which has a desired bending function. Can be said. further,
In addition, if the area surface of the flexible wiring board 1'is made uneven by the partial adhesion of the leaked adhesive to the non-circuit forming area 2 ", masking in the formation of the outer layer circuit by photoetching or solder resist ink. The adverse effects such as coating.

The present invention has been made in consideration of the above circumstances, and it is possible to easily obtain a highly reliable rigid-flex type printed wiring board without requiring complicated steps, special equipment and skill. The purpose is to provide a possible manufacturing method.

[0007]

A method for manufacturing a printed wiring board according to the present invention comprises a hard printed wiring board provided with a groove that can be separated from a circuit formation region and a non-circuit formation region.
A step of stacking and arranging on the surface of the flexible wiring board with an insulating adhesive layer interposed in a portion corresponding to the circuit forming area of the hard printed wiring board, and integrating the stacked and arranged laminate by heating and pressing. And a step of separating the non-circuit forming region of the rigid printed wiring board of the integrated laminated body with a separable groove portion, and peeling off the flexible printed wiring board surface. When laminating and arranging a rigid printed wiring board on the board, a non-adhesive piece corresponding to the area where no insulating adhesive layer is interposed is attached and arranged on the flexible wiring board surface or the rigid printed wiring board surface. And
That is, according to the present invention, in the manufacture of a rigid-flex type printed wiring board, the rigid non-circuit formation is performed by a flow of an adhesive agent that bonds and integrates the opposing surfaces of the flexible wiring board surface and the rigid circuit formation region surface. In order to completely prevent the area surface from adhering to the flexible wiring board surface, it is essential to interpose a non-adhesive body piece.

[0008]

According to the method for manufacturing a printed wiring board according to the present invention, a region where adhesion / integration or inflow of an adhesive is not desired, in other words, a region where the rigid non-circuit forming region and the flexible wiring board face each other. A non-adhesive piece is selectively attached to one of the facing surfaces so as to fill the space. For this reason, melting and outflow (inflow) of the adhesive that adheres and integrates the opposing surfaces of the flexible wiring substrate surface and the rigid circuit formation region surface can be easily and reliably prevented. In other words, the region where the adhesive is not desired to be melted / flowed out is temporarily filled with the non-adhesive body piece, and the adhesive is prevented from flowing into the region, so that the rigid non-circuit forming region can be easily separated and peeled. Moreover, since the non-adhesive piece does not cause a positional displacement due to temporary fixing, and the separating surface is linear (non-concave surface), the flexible wiring board region and the rigid type exhibiting bendability are provided. It is possible to always obtain a printed wiring board in which the circuit forming area is arranged and integrated with high precision.

[0009]

Embodiments of the present invention will be described below with reference to FIGS. 1 (a) to 1 (c), 2 (a) to 2 (b), and 3 (a) to 3 (c).

Example 1 FIGS. 1 (a) to 1 (c) show a method of manufacturing a printed wiring board according to the present invention, in which various starting materials are positioned and laminated / laminated.
It is sectional drawing which showed the aspect arrange | positioned typically and it is performed as follows. First, a required wiring conductor (wiring pattern) 5a is formed on one main surface, and a copper foil 5b is attached to the other main surface.
For example, a glass epoxy-based hard printed wiring board 5 having a thickness of 0.2 mm is prepared, and the hard printed wiring board 5 has a non-circuit forming area 5 ″ on the wiring conductor 5a forming surface, which is slightly larger than the area 5 ″ surface. Non-adhesive piece 6, eg 100 μm thick
Attach a piece of polyethylene terephthalate film (Fig. 1 (a)).

Next, the non-adhesive body piece 6 is selectively attached to the hard printed wiring board 5, and the non-adhesive body piece 6 is inserted by, for example, a Victoria mold to penetrate the copper foil of the hard printed wiring board 5. 5b, or a groove (slit) 5c for cutting that reaches the vicinity thereof is drilled (after the process shown in FIG. 1 (b),
The non-adhesive piece 6 on the larger portion (outside the groove 5c for separation) is peeled off.

On the other hand, a portion corresponding to the non-circuit forming area 5 "of the rigid printed wiring board 5 is provided with an insulating adhesive sheet 7 selectively opened, for example, a polyimide prepreg sheet and a flexible wiring board 8. Prepare,
As shown in FIG. 1 (c), the hard printed wiring board 5 to which the insulating adhesive sheet 7 and the non-adhesive piece 6 are attached is positioned and laminated / arranged on the surface of the flexible wiring board 8.

After the laminated body is formed in this manner, it is heated and pressed under the conditions of 70 to 180 ° C. and 25 to 35 kg / cm ² , for example, to obtain an integrated laminated body. About this integrated laminated body, copper foil for forming the outer layer circuit on the surface
5b is photo-etched to form a desired outer layer circuit in a portion corresponding to the circuit forming region (hard wiring board unit) 5'of the hard printed wiring board 5, while forming a non-circuit of the hard printed wiring board 5. The unnecessary portion such as the portion corresponding to the region 5 ″ is removed by etching.

After forming the required outer layer circuit and forming a so-called rigid printed wiring board unit (5 ') consisting of the circuit forming region 5'and the outer layer circuit, outer shape processing and the like are performed, and one main surface is exposed. By peeling off the non-circuit forming region 5 ″ of the rigid printed wiring board 5 from the surface of the flexible wiring board 8, a rigid-flex type printed wiring board having good dimensional accuracy and appearance can be obtained as desired. Flexible wiring board 8
In the process of peeling off the non-circuit forming area 5 ″ from the surface, the non-adhesive piece 6 is interposed between the flexible wiring substrate 8 surface and the non-circuit forming area 5 ″ surface, and no adhesive is intervening or flowing in. It can be easily peeled and removed. Here, since the non-adhesive piece 6 is temporarily fixed, it can be easily detached and removed, and the temporary fixing causes a positional deviation in the process of stacking and integrating by heating and pressing. There was no.

Example 2 FIGS. 2 (a) and 2 (b) are sectional views schematically showing another example of the embodiment. In Example 1 described above, the non-circuit forming region 5 "of the hard printed wiring board 5 is covered. , The non-adhesive body piece 6 was selectively attached,
In this example, the same procedure was performed except that the non-adhesive piece 6 was selectively attached to the surface of the flexible wiring board 8 corresponding to the non-circuit forming area 5 ″ of the hard printed wiring board 5, Similar to the case of Example 1, a rigid-flex type printed wiring board having good dimensional accuracy and appearance was obtained.

Embodiment 3 FIGS. 3 (a) to 3 (c) are sectional views schematically showing another embodiment, which corresponds to a modification of Embodiment 2 described above. First, after the non-adhesive piece 6 is selectively adhered to the surface 8'of the flexible wiring board 8 to be finally exposed (a region exhibiting a bending action) (Fig. 3 (a)), the selective adhesion is performed. A portion (area) corresponding to the attached non-adhesive body piece 6 is provided with an insulating adhesive sheet 7 which is pre-opened, a hard printed wiring board 5 having wiring conductors 5a on both sides, and a copper foil 5b (see FIG. 3). As shown in (b)), position and stack and arrange.

After the laminated body is formed in this manner, it is heated and pressed under the conditions of, for example, 70 to 180 ° C. and 25 to 35 kg / cm ² to obtain an integrated laminated body. About this integrated laminated body, copper foil for forming the outer layer circuit on the surface
5b is photo-etched to form an outer layer circuit corresponding to the circuit forming area (hard wiring board unit) 5'of the hard printed wiring board 5, while a portion corresponding to the non-adhesive body piece 6 (hard printed wiring board). The unnecessary portion such as the non-circuit forming region 5 ″ of 5) is removed by etching.

After forming the required outer layer circuit to form a so-called rigid printed wiring board unit (5 ') consisting of the circuit forming region 5'and the outer layer circuit, external processing is performed, and then the exposed non-bonded portion. By peeling off the body piece 6 from the surface of the flexible wiring board 8, a rigid-flex type printed wiring board excellent in dimensional accuracy and appearance can be obtained as desired. Here, since the non-adhesive piece 6 is temporarily fixed, it can be easily detached and removed, and the temporary fixing causes a positional deviation in the process of stacking and integrating by heating and pressing. There was no.

The present invention is not limited to the above examples, and various modifications can be made within the scope of the gist of the invention. For example, in the above, the polyimide prepreg sheet is exemplified as the adhesive layer sheet, but an epoxy prepreg sheet or a combination of a polyimide prepreg sheet and an epoxy prepreg sheet may be used, and the point is to select in consideration of the affinity for the adherend. Good.

[0020]

As described above, according to the method for manufacturing a printed wiring board of the present invention, the adhesive for bonding and integrating the opposing surfaces of the flexible wiring board surface and the rigid type circuit formation region surface is Melting and outflow (inflow) to an undesired area is easily and surely prevented. In other words, the problem that the adhesive that melts in the manufacturing process flows into the separation and separation area of the rigid non-circuit forming area is completely eliminated (avoided) or prevented. Peeling can be done easily, and since the separating surface is linear (non-concave surface),
Both the flexible wiring board region and the rigid type circuit forming region exhibiting bendability can function as a printed wiring board that is arranged and integrated with high precision.

[Brief description of drawings]

FIG. 1 schematically shows an embodiment of a method for manufacturing a printed wiring board according to the present invention, in which (a) selectively attaches a non-adhesive body piece to a non-circuit forming region surface of a hard printed wiring board. The cross-sectional view, (b) is a cross-sectional view of the hard printed wiring board to which the non-adhesive body piece is attached, and has a groove for cutting, and (c) is a cross-sectional view in which the respective materials are aligned and stacked and arranged.

FIG. 2 schematically shows another embodiment of the method for manufacturing a printed wiring board according to the present invention, in which (a) corresponds to a non-circuit forming area of a prepreg hard printed wiring board on a flexible wiring board surface. A cross-sectional view in which non-adhesive body pieces are selectively attached to the positions, and (b) is a cross-sectional view in which the respective materials are aligned and stacked and arranged.

FIG. 3 schematically shows still another embodiment of the method for manufacturing a printed wiring board according to the present invention, in which (a) corresponds to the non-circuit forming area of the hard printed wiring board on the surface of the flexible wiring board. Sectional view where non-adhesive body pieces are selectively attached at the specified positions, (b) is a sectional view in which each material is aligned and stacked, and (c) is a sectional view in which the outer layer circuit is formed after stacking and integration. .

FIG. 4 is a cross-sectional view showing a structural example of a rigid-flexible printed wiring board.

FIG. 5 is a cross-sectional view schematically showing a state in which the respective materials are aligned and laminated / arranged in the embodiment of the conventional method for manufacturing a rigid-flexible printed wiring board.

FIG. 6 is a cross-sectional view showing a main part when laminated and integrated by a conventional method for manufacturing a rigid-flexible printed wiring board.

FIG. 7 is a perspective view schematically showing a state in which a non-circuit forming region of a hard printed wiring board is separated and peeled off in an embodiment of a conventional printed wiring board manufacturing method.

[Explanation of symbols]

1,8 ... Flexible wiring board 1 ', 8' ... Peeled portion of flexible wiring board (foldable portion)
1a ... wiring conductors of flexible wiring board 2, 2 ',
5 '... rigid printed wiring board unit 2 ", 5" ...
Non-circuit forming areas 2a, 2a ', 5a ... Wiring conductors 2d, 5b of hard printed wiring board unit ... Copper foils 2c, 5c for forming outer layer circuit ... Decoupling groove 3 ... Through hole connection 4, 7 ... Insulating adhesive Sheet 4a ... Insulating adhesive sheet window 6 ... Non-adhesive piece

Claims (1)

[Claims] 1. A hard printed wiring board provided with a groove that can be separated from a circuit formation area to a non-circuit formation area and is provided with an insulating adhesive layer at a portion corresponding to the circuit formation area of the hard printed wiring board. Stacking and arranging on the flexible wiring board surface, integrating the laminated and arranged laminate by heating and pressing, and separating the non-circuit forming region of the rigid printed wiring board of the integrated laminate. In a method for manufacturing a printed wiring board, which comprises a step of separating and separating at a separable groove portion, in laminating and arranging a hard printed wiring board on the surface of the flexible wiring board, an area where an insulating adhesive layer is not interposed is placed. Manufacture of a printed wiring board characterized in that a corresponding non-adhesive piece is attached and arranged on the surface of a flexible wiring board or the surface of a hard printed wiring board. Method.