JP2006210618A - Printed wiring board and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To align a flexible printed-wiring board and a reinforcing plate accurately, to secure improved bending properties in the flexible printed-wiring board, and to prevent the flexible printed-wiring board from being damaged when it is bent in the printed-wiring board, having the flexible printed-wiring board in which a circuit pattern is formed and the reinforcing plate crimped to the flexible printed-wiring board. <P>SOLUTION: The reinforcing plate 1 made of a hard material is molded in a prescribed shape and is directly crimped to the flexible printed-wiring board 2 for affixation. Then, after crimping the reinforcing plate 1 to the flexible printed-wiring board 2, a circuit pattern 5 is formed in the flexible printed-wiring board 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printed wiring board having a flexible printed wiring board on which a circuit pattern is formed, and a reinforcing board pressure-bonded to the flexible printed wiring board, and a method for manufacturing the printed wiring board.

  In recent years, various electronic devices have been required to be reduced in size, thickness, and weight, and printed wiring boards constituting such electronic devices are also required to be reduced in size, thickness, and high integration. Has reached. In addition to so-called rigid printed wiring boards using glass epoxy substrates or the like, various forms of printed wiring boards have been put into practical use. For example, flexible printed wiring boards (FPC), multilayer printed wiring boards, and the like have been put into practical use. The flexible printed wiring board has a circuit pattern formed on the flexible printed wiring board having flexibility, and since it is thin, the space occupied by the printed wiring board can be reduced, or the housing is Widely used in electronic devices that can be bent.

  As shown in FIG. 5, the flexible printed wiring board has a configuration in which a polyimide base material 101 and a copper foil to be a circuit pattern 102 are bonded together. The circuit pattern 102 is formed by etching a copper foil. On the circuit pattern 102, an insulating layer 103 made of a coverlay film or a solder resist is formed as necessary for insulation protection.

  And in order to reinforce this flexible printed wiring board 104 in order to attach electronic parts, such as a connector and a switch, to such a flexible printed wiring board 104, it is described in Patent Document 1. In addition, a printed wiring board in which a reinforcing plate 105 is bonded to a predetermined position on the flexible printed wiring board 104 has been proposed.

  In this printed wiring board, a reinforcing plate 105 made of a hard material such as a metal such as stainless steel is formed in a predetermined shape in advance. The shape processing of the reinforcing plate 105 is performed by punching using a mold or the like. The reinforcing plate 105 is provided with an adhesive layer 106. Then, the reinforcing plate 105 is adhered to a predetermined portion of the flexible printed wiring board 104 on which the circuit pattern 102 is formed by the adhesive layer 106. The reinforcing plate 105 and the flexible printed wiring board 104 are aligned with reference holes 107 and 108 provided in the flexible printed wiring board 104 and the reinforcing plate 105, respectively. This is done by penetrating. Then, a high-temperature and high-pressure press is performed, and the flexible printed wiring board 104 and the reinforcing plate 105 are bonded to each other through the adhesive layer 106.

Moreover, in this printed wiring board, as shown in FIG. 6, before forming the copper foil 102a in the circuit pattern 102, the board | plate material 105a used as the material of the reinforcement board 105 with respect to the polyimide base material 101 is hot-pressed. There has also been proposed a manufacturing method in which pressure bonding is carried out by means of, for example. In this manufacturing method, next, a circuit pattern 102 is formed, and an insulating layer 103 is formed on the circuit pattern 102. Then, using the position of the circuit pattern 102 as a reference, an etching mask 110 is formed on the plate material 105a. When the portion of the plate material 105a where the etching mask 110 is not formed is removed by an etching process, the reinforcing plate 105 is formed.
No. 06-004579

  By the way, in the conventional printed wiring board as described above, when the reinforcing plate 105 and the flexible printed wiring board 104 are bonded together via the adhesive layer 106, the reinforcing plate 105 and the flexible printed wiring board 104 It is difficult to accurately align the positions of the reinforcing plate 105 and the flexible printed wiring board 104. In addition, when the reinforcing plate 105 and the flexible printed wiring board 104 are bonded together, the adhesive layer 106 is pressed at a high temperature and a high pressure to press the adhesive layer 106 whose viscosity decreases and fluidity increases at a high temperature. Misalignment with the printed wiring board 104 is likely to occur.

  Further, since the reinforcing plate 105 and the flexible printed wiring board 104 are pressed together at a high temperature and a high pressure, the molten adhesive oozes out as shown in FIG. As described above, the adhesive material that has oozed out between the reinforcing plate 105 and the flexible printed wiring board 104 may cause foreign matters to adhere or cause the flexibility of the flexible printed wiring board 104 to deteriorate. There is a fear.

  Furthermore, when the flexible printed wiring board 104 is small, the size of the reinforcing plate 105 is extremely small, and it is difficult to bond these reinforcing plates 105 individually.

  When the reinforcing plate 105 is formed by etching from the plate material 105a bonded to the flexible printed wiring board 104, the peripheral edge surface portion of the reinforcing plate 105 is removed from the etching mask 110 as shown in FIG. The taper is widened toward the flexible printed wiring board 104. That is, the etching is performed according to the size of the etching mask 110 in the vicinity of the etching mask 110, but the etching is difficult to enter in the vicinity of the flexible printed wiring board 104 because the etching liquid is difficult to enter. The plate 105 becomes large. Such a tendency becomes more prominent as the plate material 105a serving as the reinforcing plate 105 is thicker.

  The peripheral edge surface portion of the reinforcing plate 105 has such a taper shape, and there is a possibility that the edge portion of the reinforcing plate 105 may damage the flexible printed wiring board 104 when the flexible printed wiring board 104 is bent. is there.

  Therefore, the present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a flexible printed wiring board on which a circuit pattern is formed and a reinforcing plate that is pressure-bonded to the flexible printed wiring board. In the printed wiring board, the alignment between the flexible printed wiring board and the reinforcing board is accurately performed, and good flexibility of the flexible printed wiring board is ensured. Furthermore, the flexible printed wiring board It is to provide a printed wiring board in which the flexible printed wiring board is not damaged when it is bent, and to provide a method for manufacturing such a printed wiring board.

  The printed wiring board manufacturing method according to the present invention includes at least one of the following configurations in order to solve the above-described problems.

[Configuration 1]
A reinforcing plate made of a hard material is molded into a predetermined shape, and the reinforcing plate molded into a predetermined shape is directly bonded to a flexible printed wiring board and pasted.

[Configuration 2]
In the printed wiring board manufacturing method having the configuration 1, the circuit board is formed on the flexible printed wiring board after the reinforcing board molded into a predetermined shape is pressure-bonded to the flexible printed wiring board. To do.

  The printed wiring board according to the present invention has the following configuration.

[Configuration 3]
A flexible printed wiring board on which a circuit pattern is formed, and a reinforcing plate made of a hard material and molded into a predetermined shape and pressure-bonded to the flexible printed wiring board. It is characterized by being formed as a surface substantially perpendicular to the main surface portion.

  In the printed wiring board and the manufacturing method thereof according to the present invention, the adhesive plate is not used for bonding the reinforcing plate and the flexible printed wiring board, and is directly bonded and bonded, so that the adhesive material does not bleed out. The problem caused by the bleeding of the adhesive does not occur.

  Moreover, in this printed wiring board and its manufacturing method, since the circuit pattern of a flexible printed wiring board is formed according to a reinforcement board, alignment with a flexible printed wiring board and a reinforcement board is performed with high precision. be able to.

  Furthermore, in this printed wiring board and the manufacturing method thereof, the reinforcing plate is molded into a predetermined shape in advance before being crimped to the flexible printed wiring board, so that the peripheral end surface portion is substantially perpendicular to the main surface portion. It is formed as a flat surface. Therefore, there is no problem due to the peripheral edge surface portion of the reinforcing plate being tapered.

  That is, the present invention relates to a printed wiring board having a flexible printed wiring board on which a circuit pattern is formed and a reinforcing board crimped to the flexible printed wiring board. The positioning of the flexible printed wiring board is performed accurately, and the flexible printed wiring board is secured with good flexibility. Further, when the flexible printed wiring board is bent, the flexible printed wiring board is damaged. It is possible to provide a printed wiring board and a manufacturing method thereof.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  The printed wiring board according to the present invention includes a flexible printed wiring board having flexibility and a reinforcing plate made of a hard material and press-bonded to the flexible printed wiring board.

[First Embodiment]
FIG. 1 is a cross-sectional view showing steps in a first embodiment of a method for manufacturing a printed wiring board according to the present invention.

  In the method for manufacturing a printed wiring board according to the present invention, first, as shown in FIG. 1 (a), a reinforcing material 1 is formed by molding a hard material such as a metal such as stainless steel into a predetermined shape. Keep it. The reinforcing plate 1 is formed by etching or punching using a mold.

  And this reinforcement board 1 is directly crimped | bonded to the flexible printed wiring board 2, as shown to (a) in FIG. The flexible printed wiring board 2 has a configuration in which a polyimide base material 3 and a copper foil 4 that becomes a circuit pattern by being etched are bonded together. Thus, when the reinforcing plate 1 is pressure-bonded, the circuit pattern is not yet formed.

  For the flexible printed wiring board 2, the reinforcing plate 1 is directly bonded to the polyimide base material 3 side. That is, without using an adhesive, the flexible printed wiring board 2 and the reinforcing board 1 are heated to about 300 ° C., and the flexible printed wiring board 2 and the reinforcing board 1 are bonded by pressure bonding. Match.

  Next, as shown in FIG. 1B, the circuit pattern 5 is formed by etching the copper foil 4 of the flexible printed wiring board 2. The circuit pattern 5 is formed on the basis of the position of the reinforcing plate 1. That is, the etching mask is formed on the copper foil 4 using the reinforcing plate 1 as a position reference. Therefore, the positional accuracy between the reinforcing plate 1 and the circuit pattern 5 is extremely high.

  Then, as shown in FIG. 1 (c), on the circuit pattern 5, an insulating layer 6 made of a polyimide and an adhesive material or a solder resist is formed on the circuit pattern 5 for insulation protection as needed. To do. In this manner, a printed wiring board is completed in which the reinforcing board 1 made of a hard material and molded into a predetermined shape is pressure-bonded to the flexible printed wiring board 2 on which the circuit pattern 5 is formed.

  FIG. 2 is a cross-sectional view showing the shape of a reinforcing plate formed by etching.

  In this printed wiring board, when the reinforcing plate 1 is formed by etching, as shown in FIG. 2, the reinforcing plate 1 has a peripheral end surface portion 1a having a surface substantially perpendicular to the main surface portion 1b. Is formed. When formed by etching, the edge portions on both sides of the peripheral edge surface portion 1a have a slightly eroded shape, but such erosion occurs equally on both surfaces of the reinforcing plate 1, and therefore the peripheral edge surface portion 1a. Is maintained as being substantially perpendicular to the main surface portion 1b.

  FIG. 3 is a cross-sectional view showing the shape of a reinforcing plate formed by punching using a mold.

  Further, in this printed wiring board, even when the reinforcing plate 1 is formed by punching using a mold, as shown in FIG. 3, the reinforcing plate 1 has a peripheral end surface portion 1a formed on the main surface portion 1b. It is formed as a substantially vertical surface.

  Therefore, in this printed wiring board, good flexibility of the flexible printed wiring board 2 is ensured. Furthermore, when the flexible printed wiring board 2 is bent, the flexible printed wiring board 2 is also bent. Is not damaged by the edge portion of the reinforcing plate 1 or the like.

[Second Embodiment]
FIG. 4 is a plan view showing the shape of the reinforcing plate in the second embodiment of the method for manufacturing a printed wiring board according to the present invention.

  In the method for manufacturing a printed wiring board according to the present invention, the reinforcing plate 1 may be formed by connecting a plurality of reinforcing plates 1 in a sheet form as shown in FIG. In this case, each reinforcing plate 1 is connected to a frame body 7 which is a non-product part via a narrow support beam portion 7a.

  Then, each of the reinforcing plates 1 formed into a sheet shape is pressure-bonded to a sheet formed by connecting a plurality of flexible printed wiring boards 2 corresponding to the reinforcing plates 1. And it etches with respect to the copper foil 4 of each flexible printed wiring board 2, and the circuit pattern 5 is formed in each.

  Thus, by using the reinforcing plate 1 formed into a sheet shape by connecting a plurality of sheets, it is attached to the flexible printed wiring board 2 formed into a sheet shape by connecting a plurality of sheets. Since the printed wiring board 2 is easier to handle than the single piece, product defects such as bending of the flexible printed wiring board 2 and generation of wrinkles in the process of forming the circuit pattern 5 and the insulating layer 6 are performed. Can be reduced.

  In this state, a plurality of printed wiring boards are connected. This printed wiring board can be shipped, transported, etc. in a state where a plurality of printed wiring boards are connected in this way. After that, when each flexible printed wiring board 2 is separated into individual flexible printed wiring boards 2, if each reinforcing plate 1 and support beam portion 7a are separated by a mold, etching, or the like, A plurality of printed wiring boards to which the reinforcing plate 1 is bonded are obtained.

It is sectional drawing which shows the process in 1st Embodiment of the manufacturing method of the printed wiring board which concerns on this invention. It is sectional drawing which shows the shape of the reinforcement board formed by the etching process in the manufacturing method of the said printed wiring board. It is sectional drawing which shows the shape of the reinforcement board formed by the punching process using the metal mold | die in the manufacturing method of the said printed wiring board. It is a top view which shows the shape of the reinforcement board in 2nd Embodiment of the manufacturing method of the printed wiring board which concerns on this invention. It is sectional drawing which shows the process in the manufacturing method of the conventional printed wiring board. It is sectional drawing which shows the process in the other example of the manufacturing method of the conventional printed wiring board. It is sectional drawing which shows the state of the seepage of the adhesive material in the conventional printed wiring board. It is sectional drawing which shows the shape of the reinforcement board in the conventional printed wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reinforcement board 2 Flexible printed wiring board 3 Polyimide base material 4 Copper foil 5 Circuit pattern

Claims (3)

A reinforcing plate made of a hard material is molded into a predetermined shape,
A method of manufacturing a printed wiring board, wherein the reinforcing plate molded into the predetermined shape is directly bonded to a flexible printed wiring board. After pressing the reinforcing plate molded into the predetermined shape to the flexible printed wiring board,
The method of manufacturing a printed wiring board according to claim 1, wherein a circuit pattern is formed on the flexible printed wiring board. A flexible printed wiring board on which a circuit pattern is formed;
A reinforcing plate made of a hard material, molded into a predetermined shape, and pressed against the flexible printed wiring board,
The printed circuit board according to claim 1, wherein the reinforcing plate has a peripheral edge surface portion formed as a surface substantially perpendicular to the main surface portion.

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