JPH02273985A - Manufacture of three-dimensional wiring circuit board - Google Patents

Abstract

PURPOSE:To manufacture a three dimensional wiring circuit board and contrive manufacturing of thin, small-sized, lightweight, miniaturized electronic apparatuses with its wiring board by crystallizing this wiring board after having a curved face deformed by using required curvature during the manufacture of its board. CONSTITUTION:While applying pressure to shaping molds 13 and 14 under pressure of 10kg/cm<2>, the molds 13 and 14 are allowed to raise a temperature. When the temperature reaches 180 deg.C, pressing pressure is increased further up to 30kg/cm<2> and this state is maintained for about 20min. The molds are cooled up to a normal temperature and then press operation is complete. When its molding comes to an end, a printed wiring board is taken out from the molds 13 and 14 and then, a three dimensional wiring circuit board 12 which is pressed into shaping at a prescribed curvature is obtained. This circuit board 12 is processed by heating and operation work for about 20 min. by the use of a hot press and then its initial weak noncrystal state undergoes a transmission to a completely crystallized state that is superior in hardness. Then, even though a force is applied from the outside so that it may return back to a flattened state shown prior to crystallization, it reverts to a curved state as soon as the outside force is released. Such a property enables this circuit board to have three dimensional wiring and contrives manufacturing of thin, small sized, lightweight, miniaturized electronic apparatuses.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method for manufacturing a three-dimensional wiring circuit board with elasticity that can be used in various electronic devices such as small electronic computers, communications, and video equipment. , its purpose is to respond immediately to the miniaturization and miniaturization of electronic equipment,
Another object of the present invention is to provide a method for manufacturing a three-dimensional wiring circuit board that is highly reliable and can be mass-produced by using existing manufacturing equipment for rigid or flexible wiring boards as is.

C. Prior Art] In recent years, for example, small electronic computers with built-in programs,
In electronic devices such as so-called personal computers, with various demands such as miniaturization, higher performance, and multi-functionality of the devices, the printed wiring boards used in the devices are also becoming more densely wired, circuits are becoming finer, etc. Naturally, a response will be necessary.

The substrates of printed wiring boards currently in practical use are mainly glass-based epoxy resin laminates, but since these laminates are hard substrates, they can only be used in a flat state. In other words, it was not possible to use it three-dimensionally by bending it. For this reason, the above-mentioned laminates not only cannot make effective use of the dead space of devices, but also can only be used on a flat surface, so there is a limit to how much they can contribute to making electronic devices lighter, thinner, shorter, smaller, and lighter. there were.

However, recently, while having the performance as a rigid substrate,
A bendable copper-clad laminate, for example, has been developed by Rogers Company in the United States under the trade name Bendflex J. This laminate is a board with characteristics intermediate between conventional rigid laminates and flexible laminates, and its structure consists of a nonwoven fabric made of polyester fibers and glass fibers, with an insulating part on one side that is impregnated and cured with epoxy resin. Alternatively, by laminating copper foil on both sides, it is provided so that it can be easily bent at room temperature. FIG. 9 shows an example using the above-mentioned bendable laminate.
is a keyboard used for small electronic computers, etc., 2 is a bendable laminate, 3 is a keyboard switch installed on this aJi12, and its terminal 4 is connected to the keyboard switch 3.
Connect to the conductive part of the product NFi2 at the installation position by soldering. Since this laminated board 2 can be easily bent at room temperature, as shown in FIG. There is an advantage that all the keyboard switches 3 can be of the same type.

[Problem to be solved by the invention]

The bendable laminate 2 has an improved elongation rate by using polyester fibers and glass fibers for the nonwoven fabric, but the insulating portion uses a thermosetting modified epoxy resin as a matrix. Although it can be bent at room temperature, the keyboard switch 3
If this operation is repeated frequently, the degree of curvature of the laminated plate 2 formed into a curved surface at room temperature will gradually collapse and return to a state close to its original shape (flat plate shape), causing the curved surface of the keyboard switch 3 to become irregularly shaped. There was a problem in that the keyboard switch 3 was deformed and the operability of the keyboard switch 3 was impaired.

In addition, in view of the above-mentioned problems, as shown in FIG. 10, for example, a rigid or flexible wiring board 6 on which W4 foil is etched on a substrate with a thickness of about 0.5 m is prepared in advance.
A hole is drilled at the same position as the through-hole portion of the wiring @ 6, and a metal plate 7 such as an aluminum plate that is insulated and curved into the required curved shape is attached to the hole, and this metal plate A printed wiring board IO has also been developed in which a keyboard switch 8 is disposed on the wiring board 7 and its terminal 9 is connected to a conductive portion of the wiring board 6 by soldering.

In the wiring Fi10 equipped with the metal plate 7, there is no problem in returning to the original shape (curved shape) by repeated operations of the keyboard switch 8, but for this reason, the use of metal plates such as aluminum machines requires an increase in the number of parts. This complicates the manufacturing process and increases weight, which goes against the trend of electronic A devices becoming lighter, thinner, shorter, smaller, and more compact.Additionally, the increased number of manufacturing steps impedes productivity and raises manufacturing costs. there were.

In view of the above-mentioned problems, the present invention has been developed by forming a conductive pattern on a specially processed flat insulating substrate and then bending the insulating substrate. It is an object of the present invention to provide a method for manufacturing a three-dimensional wiring circuit board that can maintain a curved state without returning to a flat state.

[Means and effects for solving the problems] The present invention is based on a thermoplastic high viscosity saturated polyester resin, filled with glass fiber and inorganic filler, and extruded to form an insulating substrate, and before crystallization. That is, by forming a conductor pattern in an amorphous state and then performing a thermal deformation process to crystallize the leading edge substrate, it is possible to manufacture a wiring board with excellent self-returnability. By deforming the curved surface with the required curvature during manufacturing and crystallizing it, it has a certain degree of elasticity, and
Even if force is applied to the curved surface deformation part, it does not return to the original flat state at all, and it is possible to manufacture a three-dimensional wiring circuit board that can maintain the curved surface deformation state, and by using this wiring board, it is possible to manufacture electronic devices. It is characterized by being able to contribute to reduction in weight, thickness, and size.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4.

First, manufacturing of the insulating substrate used in the three-dimensional wiring circuit board of the present invention will be explained. The insulating substrate is made by filling a thermoplastic high-viscosity saturated polyester resin with glass fibers and an inorganic filler, and then forming the composite to a desired thickness (approximately 0.5 to
This insulating substrate is an electrically insulating material developed by Unitika Co., Ltd., and the product name ``Unirate J'' falls under this category. When it is extruded into a shape, it is in an amorphous state and has high elasticity, but when heated to the required temperature, it crystallizes and maintains the specified shape permanently, and even when excessive external force is applied. It is provided with elasticity so that it does not become flat and can self-return to a predetermined shape.

Next, a first embodiment will be described in which a three-dimensional wiring circuit board 12 used for a keyboard 11 for a small electronic computer shown in FIG. 4 is manufactured using the amorphous insulating substrate.
This will be explained with reference to FIGS.

In FIG. 1, an adhesive sheet is placed on an amorphous insulating substrate that has been extruded into a sheet shape and laminated to a desired thickness to form a mold, at a temperature of about 50'C and under a pressure of about 10 kg/d. Temporary adhesion was performed for 20 minutes, and then a 35μ thick copper foil was heated and pressed on the adhesive sheet using a hot roll press at approximately 60°C and 10kg/cni. Then perform the laminating process. Next, an etching resist for forming a conductor pattern is printed on the copper foil and cured, followed by etching treatment using an etching agent. Solder mask, except for the areas that require work,
Print and cure. Thereafter, the insulating substrate subjected to the above-mentioned treatments is simultaneously punched using a press mold to form holes for mounting electronic components and to prepare the external shape, thereby manufacturing a flat printed wiring board. At this point, the printed wiring board is in a highly elastic and flexible amorphous state. Next, the printed wiring board is molded into a predetermined curved shape to be compatible with electronic equipment that uses it. In this embodiment, in order to be used as a printed wiring board for the keyboard 11, male and female shaping molds 13 and 14 made of aluminum for forming curved surfaces as shown in FIG. 2 are used. That is, in order to form the flat printed wiring board into a predetermined curved shape,
These molds 13 and 14 are inserted between the heating plates of a hot press (not shown), and the temperature of the molding molds 13 and 14 is raised to about 160°C by the heating plate, and then press is performed. Perform the operation and set the shaping mold 13.14 to 1.
While pressurizing at 0 kg/cd, the temperature of the molds 13 and 14 was raised to approximately 180°C, and when the temperature reached 180°C, the press pressure was further increased to 30 kg/c+1 to maintain this state at approximately 180°C. Hold for 20 minutes. When this is cooled to room temperature and the pressing operation is completed, the printed wiring board that has been molded is taken out from the mold 13 and 14, as shown in Figure 3.
A three-dimensional wiring circuit board 12 that is press-molded with a predetermined curvature can be manufactured.

This circuit board 12 progresses from a soft, amorphous state to a stiff, completely crystalline state by heating and processing work using a hot press for about 20 minutes, and is subjected to an external force that attempts to return it to the flattened state before crystallization. Even when the external force was applied, the pestle returned to its curved state as soon as the external force was released, and no change was observed in its curvature or shape.

Next, the structure of the keyboard 11 using the three-dimensional wiring circuit board 12 will be explained. In FIG. 16 to the circuit board 121
By connecting to the conductive part of the surface by soldering, a curved keyboard 11 is manufactured in which the keyboard switch 15 is arranged in a curved manner so that it can be easily operated along the curved surface of the circuit board 12, as shown in FIG. can do.

It goes without saying that electronic components (not shown) are mounted on the three-dimensional wiring circuit board 12.

Next, as a second embodiment of the present invention, the structure of a three-dimensional wiring circuit board shown in FIG. 5, which is a combination of the amorphous insulating substrate and a flexible printed wiring board, will be explained. In Fig. 6, a thickness of 3
5μ copper foil in a hot roll press at approximately 60°C, 10k
The lamination process is performed by heating and pressurizing the product under conditions of g/cd for about 20 minutes. Next, semi-cure for 3 days at a temperature of approximately 70°C, and then further cure for approximately 15 days.
After-cure for 10 hours at a temperature of 0°C to produce a flexible print material. Next, an etching resist for forming a conductor pattern on the board is printed (or photoresist) on the copper foil and cured, followed by an etching treatment using an edger liquid, and further, during mounting. For soldering, solder resist is printed, cured, and covered except for the areas where work is required. Thereafter, the flexible printed circuit board that has been subjected to each of the above processes is simultaneously subjected to punching operations for punching holes and shaping the outer shape using a bus mold, thereby completing the production of the flexible printed wiring board. Next, an adhesive sheet is temporarily bonded onto the amorphous insulating substrate as described in the first embodiment, and as shown in FIG. Place these on top of the
A three-dimensional wiring circuit board is manufactured by laminating using a hot roll press under these conditions. Thereafter, thermal deformation processing is performed to obtain a desired shape, but since this step is the same as that of the first embodiment, its explanation will be omitted.

Next, an example in which the three-dimensional wiring circuit board I8 manufactured in the second embodiment is used in a keyboard II will be explained with reference to FIG. That is, the insulating substrate 1 is formed into a curved surface with a predetermined curvature.
2a and the flexible printed wiring board 17, a keyboard switch 15 is arranged in the same manner as in FIG. 4, and its terminal I6 is connected to the conductive part directly on the flexible printed wiring board 17 by soldering. On the other hand, as shown in FIG. 5, the extending end 17a (right side in FIG. 5) of the flexible printed wiring IJ 117 extending from the insulating substrate 12a is
It is connected to a concave connector contact 22 which is bent into a letter shape and mounted on the auxiliary printed wiring board 19.

On the other hand, on the auxiliary printed wiring board 19 provided with the connector contacts 22, an electronic component 21, such as an LSI, to be mounted on the keyboard 11 is mounted. or,
20 is a housing for mechanically fixing the connector contactor 22 and the flexible printed wiring board 17, and is mounted on the auxiliary printed wiring board 19. In this way, by forming the three-dimensional wiring circuit board 18 by combining the insulating substrate 12a that has been crystallized by thermal deformation processing and the flexible printed wiring board 17 on which a conductor pattern has been applied, the flexibility of the flexible printed wiring board 17 can be improved. The electronic components 21 of the keyboard 11 can be connected to the auxiliary printed wiring board 19 by effectively utilizing its flexibility and bending it into a U-shape to hide it under the three-dimensional wiring circuit board 18 and connecting it to the auxiliary printed wiring board 19 at this location. Since the keyboard can be arranged three-dimensionally, the depth dimension of the keyboard 11 can be significantly reduced, and the keyboard 11 can be made smaller and lighter.

Furthermore, a third embodiment of the present invention will be explained with reference to FIG.

In FIGS. 7 and 8, the first. As explained in the second embodiment, an insulating substrate 22 is provided by temporarily adhering an adhesive sheet, and a copper paste is printed on this insulating substrate 22 by, for example, a screen printing method, followed by a curing process to paste the copper paste. A conductive pattern 23 is formed. Next, in order to perform wet plating on the conductive pattern 23, an activation treatment is performed using activated palladium 24, and after that, wet plating is performed with an electroless nickel-boron alloy 25, and then the first. As in the second embodiment,
The solder resist 26 is printed, cured, and soldered except for the areas to be soldered! do. In this state, the insulating substrate 22 which has been subjected to each of the above-mentioned treatments is placed in the first. As in the second embodiment, a crystallized three-dimensional wiring circuit board 27 is molded by thermally deforming it into a desired shape using a real breath. In this case, the electroless nickel-boron alloy plating film can be stored for a long time without passivation, and the soldering of the conductive parts can be used without deteriorating the performance. Since no copper foil is used, it can be manufactured at a low cost.

〔Effect of the invention〕

As explained above, the present invention is printed! When manufacturing board A, a conductive pattern is formed on the insulating substrate that constitutes the material of the wiring board when it is in an amorphous state, or a flexible printed wiring board with a conductive pattern is bonded.
In this state, the insulating substrate is thermally deformed at a crystallization temperature to provide a crystallized three-dimensional wiring circuit board in a predetermined shape. Even when used as a wiring board, it can always be restored to its three-dimensional shape once external forces are removed, thereby eliminating the negative effects and harmful effects of external forces.

Furthermore, since three-dimensional wiring is possible, there is an advantage that electronic equipment using the circuit board of the present invention can be made lighter, thinner, shorter, smaller, and lighter.

Furthermore, when manufacturing the three-dimensional wiring circuit board of the present invention, the manufacturing process for conventional adhesive or flexible printed wiring boards can be used as is, so it can be manufactured in a short period of time and economically.

[Brief explanation of drawings]

Fig. 1 is a manufacturing process diagram of the three-dimensional wiring circuit board of the present invention;
The figure is a side view of the mold, Figure 3 is a side view showing the state in which the three-dimensional wiring circuit board has been thermally deformed, and Figures 4 and 5 show the three-dimensional wiring circuit board of the present invention used as a wiring board for a keyboard. FIG. 6 is a longitudinal cross-sectional view of main parts showing each example, and FIG. 6 shows a second embodiment of the present invention.+! ! The manufacturing process diagram, Figure 7, is the third embodiment of the present invention.
FIG. 8 is a longitudinal sectional view of main parts of a three-dimensional wiring circuit board manufactured according to the third embodiment, and FIGS. 9 and 10 are diagrams showing different usage states of a conventional wiring board. FIG.

Claims (3)

[Claims] (1) Thermoplastic high-viscosity saturated polyester resin is filled and composited with glass fiber and inorganic filler, and this is extruded to form a sheet-like amorphous insulating substrate, and an adhesive sheet is placed on this insulating substrate. Alternatively, after laminating copper foil through an adhesive layer and forming a conductive pattern in this area, thermal deformation processing is performed at a temperature that crystallizes the insulating substrate subjected to each of the above treatments to crystallize the insulating substrate. A method for manufacturing a three-dimensional wiring circuit board, characterized in that: (2) A thermoplastic high-viscosity saturated polyester resin is filled and composited with glass fiber and inorganic filler, and this is extruded to form a sheet-like amorphous insulating substrate, and this insulating substrate is coated with a conductive pattern. A three-dimensional wiring circuit board characterized in that the formed flexible printed wiring board is laminated, and both members are thermally deformed at a temperature at which the insulating substrate crystallizes, thereby crystallizing the insulating substrate. Production method. (3) Thermoplastic high viscosity saturated polyester resin is filled and composited with glass fiber and inorganic filler, and this is extruded to form a sheet-like amorphous insulating substrate, and conductive material is formed on this insulating substrate. After forming a predetermined conductive pattern with paste, chemical plating treatment such as copper or nickel is applied, and in this state thermal deformation processing is performed at a temperature that crystallizes the insulating substrate subjected to each of the above treatments to crystallize the insulating substrate. 1. A method for manufacturing a three-dimensional wiring circuit board, characterized in that: