JPH06152136A - Manufacture of printed wiring board - Google Patents

Abstract

PURPOSE:To provide a highly reliable rigid-flex type printed wiring board by melting insulation adhesive to coat/fill a slit part of a printed wiring board, without requiring complex processes and special facilities. CONSTITUTION:On the surface of a flexible wiring board 8, a hard printed wiring boards 9 with a slit 9a worked with are, with a circuit formation area 9' and an open area 9'' separable, laminated and assigned, with an insulation adhesive layer 10a positioned corresponding to the circuit formation area 9'. Then on the circuit formation area 9' surface of the printed wiring board 9, thus laminated and assigned, a copper foil 11 is laminated and assigned with an insulation adhesive layer 10b in between. During the above series of processes, the insulation adhesive layers 10a and 10b melt to coat/fill the slit 9a part of the printed wiring board 9. After thus a laminated body is formed, it is heated and pressurized. Then the copper foil 11 is etched to form an outer layer circuit, corresponding to the circuit formation area 9', while not-required part is removed by etching.

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 which also serves as a wiring connection portion and a device housing 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 structure of FIG. 3, the flexible printed circuit board 1 and the hard printed wiring board units 2 and 2'which are appropriately spaced apart from each other are integrally laminated on the surface of the flexible printed circuit board 1 to form the separated portion. There is known a printed wiring board configured to be bendable according to ′. In FIG. 3, 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. 4 to 9 schematically show the embodiments in the order of manufacturing steps.
While preparing a flexible wiring board 1 as shown in a perspective view in FIG. 5, a required wiring conductor (wiring pattern) 2a is formed on one main surface and an outer layer circuit is formed on the other main surface, as shown in a sectional view in FIG. Copper foil 2b for bonding is attached, and a disconnecting groove 2c for enabling cutting / separation of a circuit forming region (corresponding to the hard printed wiring board unit 2, 2 ') and a non-circuit forming region 2 ", A hard printed wiring board formed on the surface on which the wiring conductor (wiring pattern) 2a is formed is prepared, and an insulating board 4 with a window 4a as shown in a perspective view in FIG.
An insulating adhesive sheet 5 with a window 5a as shown in a perspective view in FIG. 6 (b) and a spacer 6 detachably fitted to the window 4a of the insulating plate 4 are prepared. Here, the window 4a of the insulating plate 4
The window 5a of the insulating adhesive sheet 5 corresponds to the non-circuit forming area 2 "of the hard printed wiring board.

Next, the prepared flexible wiring board 1, rigid printed wiring board, insulating plate 4 with window 4a, insulating adhesive sheet 5 with window 5a and spacer 6 are prepared as shown in cross section in FIG. After positioning, arranging and stacking, pressurization and heating are integrated. Thus, the flexible wiring board 1
After the hard printed wiring board units 2 and 2'are integrated on the surface, the outer layer circuit forming copper foil 2b forming the surface layer is subjected to so-called photo-etching treatment to form the required outer layer circuit, while through hole processing is performed. I do. After that, FIG.
As shown in a perspective view in FIG.
A groove 2d corresponding to a cutting groove 2c for enabling cutting / separation of the circuit forming area (in other words, the hard printed wiring board units 2 and 2 ') and the non-circuit forming area 2 "is provided with a hard printed wiring board. The non-circuit forming area 2 ″ is selectively cut off and peeled off and the spacer 6 is removed to form a foldable printed wiring board having the structure shown in FIG. can get.

[0005]

However, in the method of manufacturing a printed wiring board having the above-mentioned structure, not only the process is complicated, but also the skill of the operator is required and the productivity is inferior. To be That is,
When laminating and integrating, (a) it is necessary to form a groove 2c for separation in a hard printed wiring board forming an outer layer circuit, (b) an insulating board 4 having no wiring conductor is required, and a window
4a requires opening process, and (c) window 4a of the insulating plate 4
It requires a spacer 6 to be attached / detached to / from. These conditions not only lead to a large complication of the manufacturing work, but also require skill to form the separating groove 2c in (a) above, and the windows in (b) and (c). Since high precision and data creation for router processing are required for opening the 4a and processing the spacer 6 fitted therein, the manufacturing work is further complicated and the cost is increased.

The present invention has been made in view of the above circumstances, and provides a method for easily manufacturing a highly reliable rigid-flex type printed wiring board without requiring complicated steps or special equipment. For the purpose of provision.

[0007]

SUMMARY OF THE INVENTION A method of manufacturing a printed wiring board according to the present invention comprises a circuit of a hard printed wiring board having a circuit-formed region and a non-circuit-formed region slittable on a flexible wiring substrate surface. Layered with an insulating adhesive layer selectively interposed in the part corresponding to the formation area
The step of arranging and laminating and arranging the copper foil for forming the outer layer circuit by selectively interposing the insulating adhesive layer on the circuit forming area surface of the laminated and arranged hard printed wiring board, and integrating by heating and pressing And a step of selectively etching the copper foil for forming an outer layer circuit of the laminate to form an outer layer circuit, wherein the insulating adhesive forms an adhesive layer to form an integrated action. It is characterized by melting and covering the slit portion of the hard printed wiring board when it is formed.

That is, according to the present invention, in manufacturing a rigid-flex type printed wiring board, a so-called rigid portion is formed by slitting a rigid type circuit forming area and a copper foil for forming an outer layer circuit, while a flexible wiring board surface is formed. When forming the outer layer circuit by photo-etching or the like by covering / filling the slits with a flow of an adhesive agent for adhering and integrating the opposing surfaces of the rigid type circuit forming area surface and the copper foil surface for forming the outer layer circuit. The essence is to avoid or eliminate the adverse effects of the etching solution.

[0009]

According to the method of manufacturing a printed wiring board according to the present invention, a hard printed wiring board for forming an outer layer circuit as a starting material is unnecessary, and accordingly, a work for forming a groove for cutting is also unnecessary. Since the window opening insulating plate and the spacer having no wiring conductor are not required, the manufacturing work is greatly simplified. That is, it is possible to manufacture a highly reliable rigid-flex type printed wiring board with good productivity without requiring special skill or complicated operation, and by utilizing the flow phenomenon of the adhesive resin. It will be possible.

[0010]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 shows a method of manufacturing a printed wiring board according to the present invention, in which various starting materials are positioned and laminated and
It is sectional drawing which showed the aspect arrange | positioned typically and it is performed as follows. That is, the required flexible wiring board 8
A hard printed wiring board 9 having a slit 9a formed by using, for example, a Victoria mold so that the circuit forming region 9'and the non-circuit forming region 9 "can be separated on the surface, for example, the thickness.
A glass epoxy type printed wiring board 9 having a thickness of 0.1 mm is selectively used as an insulating adhesive layer in a portion corresponding to the circuit forming area 9 '.
10a, for example, laminated and arranged with a polyimide prepreg interposed. Then, an insulating adhesive layer 10b, for example, epoxy prepreg, is selectively interposed on the circuit forming area 9'side of the laminated and arranged hard printed wiring board 9 to form a copper foil having a thickness of about 18 μm for forming an outer layer circuit. 11 is stacked and arranged. The insulating adhesive layers 10a and 10b used in the series of laminating / arranging steps may be, for example, a sheet shape, a mesh shape, or a prepreg, but they are appropriately melted at the time of bonding / integrating, and the hard A material that can cover and fill the slit 9a of the printed wiring board 9 is selected.

After the laminated body is formed in this way, it is heated and pressed under the conditions of, for example, 70 to 180 ° C. and 25 to 35 kg / cm ^2, so that the main structure is shown in cross section in FIG. It becomes a printed wiring board. With respect to the integrated laminate, a copper foil 11 for forming an outer layer circuit on the surface is photoetched to form a required outer layer circuit on a portion of the hard printed wiring board 9 corresponding to the circuit forming area 9 '. On the other hand, unnecessary portions such as a portion corresponding to the non-circuit forming area 9 ″ of the hard printed wiring board 9 are removed by etching.

After forming the required outer layer circuit and forming a so-called rigid printed wiring board unit consisting of the circuit forming region 9'and the outer layer circuit, external processing is performed, and then one main surface is further exposed. By peeling off the non-circuit forming region 9 ″ of the hard printed wiring board 9 from the surface of the flexible wiring board 8, a desired rigid-flex type printed wiring board can be obtained. In the process of peeling off the non-circuit forming area 9 ″ from the above, an adhesive layer is not interposed between the flexible wiring board 8 surface and the non-circuit forming area 9 ″ surface, and the non-circuit forming area 9 ″ is formed into a film shape. The flowed adhesive layer can also be easily broken and removed, so that it can be easily achieved. 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 case where the wiring conductor has eight layers has been illustrated, but the wiring conductor may have a multilayer structure, and the adhesive layer may be replaced with a combination of epoxy prepreg and polyimide prepreg, instead of epoxy prepregs or polyimide prepregs. A combination thereof may be used, and the point is to select them in consideration of the affinity for the adherend.

[0014]

As described above, according to the method for manufacturing a printed wiring board of the present invention, since a groove for cutting (a non-penetrating slit), which is a complicated process, is eliminated, a series of manufacturing steps are performed. It can be significantly shortened, and in the photoetching for forming the outer layer circuit, it is possible to completely prevent the etching solution from penetrating into the inner layer wiring region of the hard printed wiring board unit. Thus, it can be said that the present invention brings about many practical advantages in combination with good productivity or mass productivity and that the manufactured printed wiring board retains and exhibits a highly reliable function.

[Brief description of drawings]

FIG. 1 schematically shows an embodiment of a method for manufacturing a printed wiring board according to the present invention, and is a cross-sectional view showing a state in which materials are aligned and laminated / arranged.

FIG. 2 is a cross-sectional view schematically showing an embodiment of a method for manufacturing a printed wiring board according to the present invention, in which a laminate of raw materials is heated and pressed to be bonded and integrated.

FIG. 3 is a cross-sectional view showing a structural example of a rigid-flexible printed wiring board.

FIG. 4 is a perspective view showing a structural example of a flexible wiring board.

FIG. 5 is a cross-sectional view showing a main part structure of a hard printed wiring board used for manufacturing a conventional rigid-flexible printed wiring board.

FIG. 6A is a perspective view showing an insulating plate used for manufacturing a conventional rigid-flexible printed wiring board, and FIG. 6B is an adhesive sheet similarly used for manufacturing a conventional rigid-flexible printed wiring board. FIG.

FIG. 7 is a cross-sectional view schematically showing an embodiment of a conventional method for manufacturing a printed wiring board, in which raw materials are aligned and laminated / arranged.

FIG. 8 is a perspective view schematically showing an embodiment of a conventional method for manufacturing a printed wiring board, showing a laminated body which is heated and pressed to be bonded and integrated.

FIG. 9 is a perspective view schematically showing an embodiment of a conventional method for manufacturing a printed wiring board, showing a state in which the laminated body bonded by heat and pressure, and bonded and integrated is subjected to outer shape processing.

[Explanation of Codes] 1,8 ... Flexible wiring board 1a ... Wiring conductor of flexible wiring board 2, 2 '... Hard printed wiring board unit 2 ",
9 "... Non-circuit forming area 2a, 2a '... Wiring conductor of rigid printed wiring board unit
2b ... Copper foil for forming outer layer circuit 2c, 2d ... Separation groove 3 ... Through hole connection 4 ... Insulation plate with window 4a ... Window of insulation plate with window 5 ... Adhesive sheet 5a ... Window of adhesive sheet 6 ... Spacer 7 … Outline processing line
9 ... Hard printed wiring board 9a ... Slit 9 '... Circuit forming area 10a, 10b ... Insulating adhesive layer
11 ... Copper foil for outer layer circuit formation

Claims (1)

[Claims] 1. A hard printed wiring board in which a circuit forming area and a non-circuit forming area are slittable so that the circuit forming area and the non-circuit forming area can be separated from each other on the surface of the flexible wiring board, and an insulating adhesive layer is selectively formed at a portion corresponding to the circuit forming area. The step of stacking and arranging with interposition, and the step of stacking and arranging the copper foil for forming the outer layer circuit by selectively interposing the insulating adhesive layer on the surface of the circuit forming area of the hard printed circuit board which is laminated and arranged. It comprises a step of integrating by heating and pressurizing and a step of selectively etching an outer layer circuit forming copper foil of the laminate to form an outer layer circuit, wherein the insulating adhesive forms an adhesive layer. Then, it melts when acting as a unit and covers the slit part of the hard printed wiring board.
A method for manufacturing a printed wiring board, which comprises filling.