JP2008117748A - Anisotropic conductive film, and method of manufacturing anisotropic conductive film, wiring board, wiring board connector and wiring board module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anisotropic conductive film which uses anisotropic conductive resin for connection of a conductor of a wiring board and certainly forms a conductive part between facing conductors and connect between required conductors. <P>SOLUTION: The anisotropic conductive film 20 includes an insulating resin film 21 which is provided with through-holes 21a bored with intervals in a thickness direction and has adhesiveness on both sides in a thickness direction and conductive parts 23 which penetrate the through-holes 21 respectively and are exposed from openings on both sides, and the conductive parts 23 conductively fasten conductors arranged in opposition on both sides of the insulating resin film 21 in a thickness direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an anisotropic conductive film, a method for producing an anisotropic conductive film, a wiring board, a wiring board connector, and a wiring board module, and more particularly, thin and small electronic devices such as mobile phone devices, digital cameras, and video cameras. In an apparatus, it is suitably used for electrical connection between wiring boards such as a flexible printed wiring board (FPC) and a hard printed wiring board (PCB).

  In recent years, electronic devices have become highly functional, and thinning and miniaturization have been promoted. Therefore, in the wiring boards accommodated in these electronic devices, the conductor pitch is reduced to 1 mm or less, and further to 0.2 mm or less. For example, a conductor that is wired on a wiring board made of PCB at a narrow pitch is FPC. It is electrically connected to a conductor wired at a narrow pitch on a wiring board made of

Conventionally, the following methods have been mainly employed as a method for electrically connecting conductors of this type of wiring board.
(1) Insert and connect an FPC conductor to a terminal in a connector mounted on a PCB.
(2) The conductors of the connection portions exposed by peeling off the insulation coating are directly soldered (Japanese Patent Laid-Open No. 8-17259, etc.).
(3) The conductors of the connection portions exposed by the conductors are connected to each other via an anisotropic conductive adhesive (Japanese Patent Laid-Open No. 2006-176716).
When the anisotropic conductive adhesive (3) is used, a film or paste in which conductive particles are dispersed in an insulating resin is used, and conductors arranged opposite to each other are connected by heating and pressing.

JP-A-8-17259 JP 2006-176716 A

The connection by the connector in (1) has an advantage that the wiring boards can be easily connected to each other and can be easily removed after the connection, but the connector housing is bulky and supports high density of parts. Difficult to do. Moreover, it is necessary to solder the lead wires of the connector, and it is difficult to cope with the narrow pitch of the connection terminals.
When the conductors of (2) are directly connected by soldering, there is an advantage that the electrical reliability is high and the connecting operation is easy. However, the conductors of narrow pitch are firmly fixed by direct soldering and usually adjacent to each other. There is a problem in that the insulating part between the conductors is formed of a thermosetting resin and the peelability is firmly fixed. Therefore, when the connection work is performed again, there is a problem that peeling is easy and the connection portion is damaged and cannot be reused.

  In the connection using the anisotropic conductive adhesive (3), since the printed wiring boards can be directly connected to each other, the size of the component can be reduced. In addition, it is possible to cope with a narrow pitch connection as compared with the connector. In anisotropic conductive adhesive, insulation performance that lowers the resistance (connection resistance) between connecting terminals facing each other in the thickness direction and increases the resistance (insulation resistance) between adjacent connection terminals in the surface direction. Is needed. However, when the connection pitch is reduced, the width of the connection terminal is reduced, and the number of conductive particles contributing to the connection is reduced, so that the contact resistance is increased. If the number of conductive particles in the anisotropic conductive adhesive is increased in order to solve this problem, the conductive particles existing between adjacent connection terminals come into contact with each other, and the insulation resistance is lowered.

In particular, in connection work between wiring boards having fine connection terminals, there is a demand for peeling once connected and reconnecting (repairing) in order to repair misalignment and the like. In addition, there is also a demand for reusing a PCB on which expensive components are mounted by temporarily separating the wiring boards that are connected when repairing the electrical equipment.
However, since the anisotropic conductive adhesive bonds the wiring boards to be connected to each other, it becomes a permanent connection and cannot be easily peeled off after being connected once, and if it is forcibly removed, the wiring board may be damaged. Although it is conceivable to reduce the adhesive strength of the adhesive in order to improve the repairability, if the adhesive strength is lowered, connection reliability may be reduced.

The present invention has been made in view of the above problems,
First, as in the case of using the anisotropic conductive adhesive of (3) above for connecting conductors of a wiring board, an anisotropic conductive film that can reliably form a conductive portion between opposing conductor wirings. It is an issue to provide.
Secondly, it is an object to provide a production method capable of easily producing a highly accurate anisotropic conductive film.
Thirdly, the conductor wiring and the insulating resin in the connecting portion can be bonded with a required adhesive force, and can be peeled off so that the conductor wiring is not damaged at the time of peeling. It is an object to provide a plate module.

In order to solve the first problem, the present invention provides:
An insulating resin film having through-holes in the thickness direction formed at intervals and having adhesiveness on both sides in the thickness direction;
A conductive portion that penetrates into each through hole and is exposed at both end openings;
The conductive portion provides an anisotropic conductive film that conducts conductors arranged opposite to both side surfaces in the thickness direction of the insulating resin film.

  As described above, the conventional anisotropic conductive adhesive has conductive particles dispersed in an insulating resin, and is heated and pressed to enclose the conductive particles between opposing terminals in the thickness direction. Although the conductivity is imparted, the anisotropic conductive film of the present invention has a through hole in the insulating resin film, and the conductive part is penetrated through the through hole to impart conductivity only in the thickness direction. . Therefore, when connecting the conductors of narrow pitch, only by interposing the anisotropic conductive film of the present invention, the conductors opposed to each other can be reliably conducted, and a short circuit does not occur between adjacent conductors.

  It is preferable that the conductive portion protrudes from at least one surface side of the insulating resin film. With this configuration, it is possible to increase the adhesive force between the conductive portion of the anisotropic conductive film and the conductor of the wiring board to improve connection reliability, and to reduce the applied pressure when adhering to the conductor of the wiring board. The compressive force applied to the wiring board can be reduced.

The conductive part is formed of one or more conductive materials selected from solder, solder paste, solder plating, other metal plating, or conductive resin paste.
When the conductive material is a solder paste or conductive resin paste, the through hole is filled with screen printing, a dispenser, etc., and in the case of solder plating or other metal plating, a plated layer is formed on the inner peripheral surface of the through hole. Is done.
When the conductive portion is formed of solder or solder paste, the adhesive force between the wiring board and the conductor can be increased.

Furthermore, it is preferable that an adhesive resin layer is provided on one or both surfaces of the insulating resin film, and the melt viscosity when the adhesive resin layer is heated is lower than the melt viscosity when the insulating resin film is heated.
When the conductive part is formed of conductive resin or plating, the adhesive force between the conductor of the wiring board is low, so the insulating resin part and the adhesive force between adjacent conductors of the wiring board are increased. A resin layer is provided.
With the above-described two-layer structure, the adhesive resin layer can be melted to fill the space between the conductor wirings, and the insulating film layer having the conductive portion is not greatly melted, and the shape of the conductive portion can be maintained. And since the board | substrate of a wiring board and an insulating resin film are adhere | attached through the adhesive resin layer which fuse | melts at the time of adhesion | attachment, a pressing force can be reduced also from this point and the compressive force loaded on the board | substrate of a wiring board can be reduced.

The adhesive resin layer preferably contains a thermoplastic resin as a main component.
As this type of thermoplastic resin, for example, polyvinyl acetal resin such as polyvinyl butyral resin, phenoxy resin, acrylic resin, methacrylic resin, polyamide, polyacetal, polyphenylene sulfide, polyimide, polytetrafluoroethylene, polyether ether ketone, polyether Examples include sulfone, urethane, polyester, polyethylene, polypropylene, and polystyrene.
The adhesive resin layer can be easily peeled off from the insulating resin portion between the conductors of the wiring board by making the melt viscosity at the time of heating lower than the melt viscosity of the insulating resin film provided with the conductive portion so as to be easily peeled off. Like that.
The adhesive resin layer is fixed to the entire surface excluding the through holes of the insulating resin film, but may be provided on the entire surface as long as it flows from the surface of the conductive portion when bonded to the wiring board by heating and pressing.
Thus, by making it possible to peel the anisotropic conductive film easily, damage to the wiring board can be reduced, and the wiring board can be reused.

The insulating resin film may be formed of a thermoplastic resin such as a phenoxy resin, a brachial resin, or an acrylic resin as long as the conductive portion can be held.
The insulating resin film may be formed of a thermosetting resin. Since thermosetting resin has excellent adhesive strength at high humidity, connection reliability is improved. Furthermore, it is more preferable to use a thermoplastic resin and a thermosetting resin in combination because the properties are balanced.

The through hole provided in the anisotropic conductive film of the present invention is set to be equal to or smaller than the conductor width, and prevents a short circuit between conductors so as not to straddle between adjacent conductors.
Further, it is preferable that the through holes are provided at a required pitch in the vertical and horizontal directions, and the through holes provided with the conductive portions are connected to one conductor at a plurality of locations in the length direction.

In order to solve the second problem described above, as a method for producing the anisotropic conductive film, a mask film provided with an opening at a position corresponding to a through hole of the insulating resin film is laminated, or the insulating resin film and the mask After laminating the film, provide a through hole,
Next, a conductive part is formed by filling the through hole with a conductive material,
Then, the manufacturing method of the anisotropic conductive film characterized by peeling the said mask film is provided.

The step of filling the through hole with a conductive material to form a conductive portion is performed by filling the through hole with solder paste or conductive resin paste through the opening of the mask film, or by electrolytic plating or electroless on the inner surface of the through hole. It is formed by plating.
As the mask film, a PET film having good releasability is preferably used.
As described above, when the conductive film is formed in the through hole by covering the surface of the insulating resin film with the mask film, the conductive part may protrude from the surface of the insulating resin film with a dimension corresponding to the thickness of the mask film. it can.

Furthermore, when providing the adhesive resin layer, the insulating resin for adhesion is applied to the surface of the edge resin film after the mask film is peeled off. Alternatively, it is formed by melting after placing an insulating resin film for adhesion.
In the step of forming the adhesive resin layer, the adhesive resin film is disposed on the surface of the insulating resin film so as to cover the front end surface of the conductive portion protruding from the surface of the insulating resin film,
Then, it is preferable that the adhesive resin film is heated and melted, and the melted resin is allowed to flow out from the front end surface of the conductive material to fill the gaps between the conductive materials.

Further, the present invention provides a wiring board having a plurality of conductor wirings provided at intervals as connection portions, wherein the anisotropic conductive film is attached in advance to the surface of the connection portion. A wiring board is provided.
The wiring board provided in the present invention may be any of a flexible printed wiring board (FPC), a flexible flat cable (FFC), and a hard printed wiring board (PCB).

In the wiring board in which the anisotropic conductive film is fixed to the connection portion, the insulating resin portion between adjacent conductors of the wiring board and the insulating resin film or the adhesive resin layer of the anisotropic conductive film are fixed. The peel strength of the fixed portion is preferably set lower than the peel strength between the conductive portion and the conductor wiring.
With this configuration, since the adhesion area between the resin parts is smaller than the adhesion area between the conductors, it can be removed without difficulty when peeling between the wiring board and the anisotropic conductive film, and damage to the wiring board can be reduced and prevented. Reusable.

When the conductive portion of the anisotropic conductive film has high adhesive strength such as solder, the conductive portion and the wiring conductor of the wiring board are bonded to each other, and the insulating resin portion between the conductive wires and the anisotropic conductive film are bonded. The insulating resin film is not necessarily fixed.
With this configuration, the insulating resin portions are not bonded to each other at the time of peeling between the anisotropic conductive film and the wiring board, and thus can be easily peeled off.

Furthermore, in the present invention, a first wiring board having a plurality of conductor wires provided at intervals as a first connection portion and a plurality of conductor wires provided at intervals as a second connection portion. A connection body with a second wiring board,
A wiring board connector is provided, wherein the first connecting portion and the second connecting portion are electrically connected by the anisotropic conductive film described above.

For example, the first wiring board is a flexible printed wiring board (FPC), and the second wiring board is a hard printed wiring board (PCB).
An FPC is disposed on one surface of the anisotropic conductive film and a PBC is disposed on the other surface. One end of the conductive material of the anisotropic conductive film is fixed to a wiring conductor of the FPC and the other end is disposed. It is fixed to the wiring conductor of the PBC.

  The method of adhering the first wiring board made of FPC and the second wiring board made of PBC with an anisotropic conductive film interposed is, for example, temporarily bonding the anisotropic conductive film to the terminal connection portion of the FPC Then, pressurize the PBC connection part with the required pressure and crimp it, and contact the FPC wiring conductor and the PBC wiring conductor with the required pressure at both ends in the thickness direction of the conductive part of the anisotropic conductive film. Then, the insulating resin film of the anisotropic conductive film or the adhesive resin layer is melted by heating at a required temperature, and bonded to the insulating resin portions of the FPC and PBC.

The FPC and PCB bonded through the anisotropic conductive film have a peel strength at 100 ° C. in a state where the FPC is bent 90 degrees with respect to the PBC and pulled in the wiring direction of the wiring conductor. It is preferable to be 500 g / cm or less.
At the time of peeling, if the insulating resin film of the anisotropic conductive film or the adhesive resin layer is present on the surface of the insulating resin film, the glass transition temperature of the resin of the adhesive resin layer is higher than the softening point of the resin. It is preferable to heat. Alternatively, it may be immersed in a solvent at room temperature.

  Furthermore, it is more preferable that the peel strength between the anisotropic conductive film and the PBC is lower than the peel strength between the anisotropic conductive film and the FPC. Thus, by reducing the peel strength between the anisotropic conductive film and the PBC, damage to the PBC at the time of peeling can be prevented and reduced.

  As described above, the first wiring board is not limited to FPC and the second wiring board is PBC, and both the first and second wiring boards may be FPC and FFC. And PBC.

  When the above anisotropic conductive film is attached in advance to either the first or second wiring board, it is preferable to attach the anisotropic conductive film to the first wiring board made of FPC. An anisotropic conductive film may be attached to the side in advance.

Furthermore, the present invention provides a wiring board module, wherein an electronic component is mounted on at least one of the first wiring board and the second wiring board of the wiring board connector.
The electronic component may be mounted on both the first wiring board and the second wiring board.
Since the anisotropic conductive film of the present invention is excellent in repairability, when an electronic component is mounted and then connected using the anisotropic conductive film, it can be reconnected even if a connection failure occurs. An expensive wiring board on which electronic components are mounted can be reused.
In the wiring board module, when the second wiring board is made of PCB, the anisotropic conductive film is bonded to one surface of the PCB, and the back side of the PCB facing the bonding side of the anisotropic conductive film An electronic component can be mounted on.

Furthermore, the present invention provides an electronic device incorporating the wiring board module.
As described above, when a wiring board module including a PCB is used, it is possible to reduce the size by reducing the connecting portion compared to the connector connection. In addition, since the components and circuit patterns can be formed at high density, the wiring board module itself can be reduced in size.
Examples of electronic devices incorporating the wiring board module include small, lightweight, thin and portable electronic devices such as mobile phone devices, cameras such as digital cameras and video cameras, portable audio players, portable DVD players, and portable laptop computers. Equipment.

  As described above, since the anisotropic conductive film of the present invention has a through hole in the insulating resin film and a conductive portion is provided in the through hole, the conductive portion is arranged in the thickness direction of the anisotropic conductive film. If it arrange | positions between the conductors arrange | positioned facing, a conductor can be reliably electrically connected. Therefore, it is particularly suitable for connection between conductors wired at a narrow pitch. In addition, the insulating resin film is provided with a conductive portion penetrating in the thickness direction, the conductive portion is exposed on the surface of the insulating resin film, and the adhesive resin layer melts on the surface when connected to the conductor of the wiring board. And the wiring board are bonded to each other, the applied pressure can be reduced, and as a result, the compressive force applied to the wiring board can be reduced.

  Furthermore, in the wiring board assembly in which the wiring conductors of the wiring boards are electrically connected via the anisotropic conductive film, the adhesion to the insulating resin portion of the wiring board is adjusted by adjusting the resin component of the anisotropic conductive film. The force can be adjusted, and when it is necessary to peel off after being connected, it is possible to peel in a state where damage to the conductor of the wiring board is prevented, and the repair performance can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 4 show a first embodiment of the present invention.
As shown in FIG. 1, the wiring board connector 10 includes a conductor wiring 32 of a flexible printed wiring board 30 (hereinafter referred to as FPC 30) that is a first wiring board, and a rigid printed wiring board that is a second wiring board. 40 (hereinafter, referred to as PCB 40) conductor wirings 42 are connected to each other at connecting portions 33 and 43.

  Specifically, the conductor 32 of the FPC 30 and the conductor 42 of the PCB 40 are electrically connected and bonded by the conductive portion 23 of the anisotropic conductive film 20 provided in the connection portion 33 of the FPC 30, and the insulating resin film 31 of the FPC 30 The substrate 41 of the PCB 40 is bonded with the adhesive resin layer 22 of the anisotropic conductive film 20, and the peel strength between the FPC 30 and the PCB 40 at 100 ° C. is set to 500 g / cm or less.

As shown in FIG. 2, the anisotropic conductive film 20 provided on the connecting portion 22 of the FPC 30 has an adhesive resin layer 22 on both surfaces of the insulating resin film 21, and the insulating resin film 21 is perforated at intervals. The provided through hole 21a in the thickness direction and the conductive portion 23 penetrating the adhesive resin layer 22 are provided, and both ends of the conductive portion 23 are exposed to the outer surface of the adhesive resin layer 22 on both sides.
While the insulating resin film 21 is made of a thermosetting resin, the adhesive resin layer 22 is made of a resin mainly composed of a phenoxy resin (thermoplastic resin), and the melt viscosity when the adhesive resin layer 22 is heated is determined to be an insulating resin. It is lower than the melt viscosity when the film 21 is heated. The conductive portion 23 is made of solder.

  In addition, the diameter of the conductive portion 23 of the anisotropic conductive film 20 is set to be smaller than the width of the conductor wirings 32 and 42 and the gap width between the conductor wirings 32 and 42, so Although the portion 23 is fixed, only one conductor wiring 32 and 42 is fixed to one conductive portion 23, respectively. This prevents the conductors 23 that are not connected from being short-circuited by the conductive portion 23.

First, as shown in FIGS. 3A and 3B, the anisotropic conductive film 20 is opened on both sides of the insulating resin film 21 having the through holes 21a at positions corresponding to the through holes 21a. A mask film 24 made of a PET film provided with 24a is laminated, and then, as shown in FIG. 3C, the through hole 21a is filled with solder to form a conductive portion 23.
Thereafter, as shown in FIG. 3D, the mask film 24 is peeled off, and the conductive portion 23 protrudes from both surfaces of the insulating resin film 21.
Next, as shown in FIG. 3 (E), an adhesive resin film 25 is disposed on both surfaces of the insulating resin film 21 so as to cover the front end surface of the conductive portion 23 protruding from the surface of the insulating resin film 21. The resin film 25 is heated and melted, and as shown in FIG. 3 (F), the molten resin flows out from the front end surface of the conductive portion 23 and fills the gaps between the conductive portions 23 to form the adhesive resin layer 22. To do.

  As shown in FIG. 4, the FPC 30 has conductor wirings 32 made of copper formed at a pitch of 0.2 mm or less, and both surfaces of the conductors 32 are covered with an insulating resin film 31. At the terminal position of the FPC 30, the insulating resin film 31 on one side is not laminated, and a connection portion 33 exposing the conductor 32 is provided.

The anisotropic conductive film 20 manufactured by the above method is attached to the connection portion 33, and the anisotropic conductive film 20 is placed so that one surface in the thickness direction of the anisotropic conductive film 20 contacts the connection portion 33. In this state, pressure is applied and heating is performed. As a result, the conductor 32 and the conductive portion 23 of the anisotropic conductive film 20 are fixed, and the melted one adhesive resin layer 22A is filled in the gap between the conductors 32 and both sides, and the adhesive resin layer 22A The insulating resin portions 31a between the conductors 32 and both sides of the insulating resin film 31 are fixed.
The peel strength of the fixing portion between the adhesive resin layer 22A and the insulating resin portion 31a is set lower than the peel strength between the conductive portion 23 and the conductor 32.

  On the other hand, as shown in FIG. 1, the PCB 40 connected to the FPC 30 is provided with a connection portion 43 at a required position on the periphery of the hard printed circuit board 41. Wiring is performed at the same pitch of 0.2 mm or less.

  Next, a method for manufacturing the wiring board connector 10 by connecting the FPC 30 and the PCB 40 will be described.

First, the conductor 42 of the PCB 40 and the conductor 32 of the FPC 30 that are electrically connected to each other are opposed to each other, and the other surface in the thickness direction of the anisotropic conductive film 20 provided on the FPC 30 is brought into contact with the connection portion of the PCB 40.
Next, the FPC 30 and the PCB 40 are pressurized and heated to fix the conductor 42 and the conductive portion 23 of the anisotropic conductive film 20, and the molten other adhesive resin layer 22 B is filled in the gap between the conductors 42 and both sides. Then, the insulating resin portions 41a are fixed between the adhesive resin layer 22B and the conductor 42 of the substrate 41 and on both sides.

  In the wiring board of the present invention having the above-described configuration, the anisotropic conductive film 20 has a through-hole 21a in the insulating resin film 21, and the conductive portion 23 is passed through the through-hole 21a so as to be conductive only in the thickness direction. Therefore, when the conductors with a narrow pitch are connected, the conductors facing each other can be reliably conducted only by interposing the anisotropic conductive film 20, and a short circuit is not generated between the adjacent conductors. In addition, since the conductive portion 23 penetrates the insulating resin film and further penetrates the adhesive resin layer to expose both ends, it is not necessary to increase the pressure when bonding to the PCB 40. Can be significantly reduced, and the compressive load on the PCB 40 can be reduced.

On the other hand, when the FPC 30 and the PCB 40 need to be peeled off, the adhesive resin layer 22 is formed of a resin mainly composed of a thermoplastic resin, and thus the adhesive resin layer 22 is softened by heating. Or it can peel easily from the resin part of PCB40 by heating and melting at the glass transition temperature of the thermoplastic resin. And since the electroconductive part 23 is also formed with the low melting metal, the adhesion interface can be melted and easily peeled off.
Further, since the melt viscosity of the adhesive resin layer 22 is lower than the melt viscosity of the insulating resin film 31 of the FPC 30, the insulating resin film 31 of the FPC 30 is not melted even when the adhesive resin layer 22 is melted. The conductor wiring can be filled and bonded with an adhesive resin while maintaining the shape of the portion.

  In this way, the adhesive resin layer 22 can be melted and the plating layer 24 made of a low melting point metal can be easily peeled to prevent the FPC 30 and the PCB 40 from being damaged during the peeling, particularly the conductor. The FPC 30 and the PCB 40 can be reused.

FIG. 5 shows a modification of the first embodiment of the present invention.
In this modification, the manufacturing method of the anisotropic conductive film 20 is different from that of the first embodiment.
As shown in FIGS. 5 (A) and 5 (B), after laminating a mask film 24 not provided with a through hole on both surfaces of an insulating resin film 21 not provided with a through hole, it is shown in FIG. 5 (C). Thus, the laminated resin film 21 and the mask film 24 are provided with a through hole 21a and an opening 24a. Since the subsequent manufacturing method is the same as that of the first embodiment, the description thereof is omitted.

  According to the said structure, when laminating the insulating resin film 21 and the mask film 24, it is not necessary to align the through hole 21a of the insulating resin film 21 and the opening 24a of the mask film, so that the laminating operation is facilitated. Can do.

FIG. 6 shows a second embodiment of the present invention.
In the anisotropic conductive film 20 of the present embodiment, the adhesive resin layer 22 is provided only on one surface of the insulating resin film 21, while the adhesive resin layer is not provided on the other surface, and the insulating resin film 21 is provided on the other surface side. The conductive portion 23 is projected from the opening end of the through hole 21a.
Also in the case of the above configuration, when the wiring boards connected to the wiring board connector are peeled off, the adhesive resin layer provided only on one surface is melted by heating and can be easily peeled off by the adhesive resin layer. it can. Moreover, the compressive load applied to the wiring board to be connected can be reduced by reducing the applied pressure during bonding.
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 7 shows a third embodiment of the present invention.
In the anisotropic conductive film 20 of the present embodiment, the conductive material 23 is formed by plating the inner surface of the through hole 21a without filling the through hole 21a of the insulating resin film 21 with a conductive material.
In FIG. 7A, the adhesive resin layer is not provided on both surfaces of the insulating resin film 21, and in FIG. 7B, the adhesive resin layer 22 is provided on both surfaces of the insulating resin film 21.
According to the said structure, since the contact area of the electroconductive part 23 of the anisotropic conductive film 20 and the conductor of a wiring board becomes small, adhering force becomes small and can peel the connected wiring boards easily. .
In addition, since another structure and an effect are the same as that of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

8 and 9 show a fourth embodiment.
The fourth embodiment includes a printed wiring board module 100 that includes an FPC 30 and a PCB 40 connected via the anisotropic conductive film 20, and an electronic component 50 is mounted on the PCB 40.

In FIG. 8, 40-1 is a main PCB, and a wiring conductor (not shown) at one end of a plurality of FPCs 30-1 to 30-4 is electrically connected to a wiring conductor (not shown) of the main PCB 40-1. They are connected by the parts P1 to P4. Further, the wiring conductor at the other end of the FPC 30-1 is connected to the wiring conductor of the sub PCB 40-2 by the electrical connection portion P5, and the wiring conductor at the other end of the FPC 30-2 is connected to the sub PCB 40-3 by the electrical connection portion P6. Connected. One end of the FPC 30-5 is connected to the sub PCB 40-3 by an electrical connection portion P7, and the other end of the FPC 30-5 is connected to the PCB 40-4 on which the in-camera 55 is mounted by an electrical connection portion P8.
The other end of the FPC 30-3 is connected to the main display 56 through an electrical connection portion P9, and the other end of the FPC 30-4 is connected to the sub display 57 through an electrical connection portion P10.
Further, the wiring 60 connected to the main PCB 40-1 is connected to the PCB 40-5, connected to the PCB 40-5 via the electrical connection portion P11, and the FFC 30-6 is connected to the PCB 40-6. Connected. In the figure, 59 is an out camera.

The main PCBs 40-1 and 40-5 have a substrate 42 on both sides thereof with electronic components such as a built-in memory, a baseband LSI, a power supply control IC, a sound source IC, an RF reception LSI, an RF transmission LSI, a switch IC, and a power amplifier. 53 is implemented.
In addition, necessary electronic components 53 are also mounted on the substrates of the sub PCPs 40-2 and 40-3.

  The electrical connection portions P1 to P11 are similar to the electrical connection portion P1 between the FPC 30-1 and the main PCB 40-1 shown in FIG. In addition, it is connected by pressurization and heating.

When the anisotropic conductive film 20 is connected to the PCB 40 by pressurizing and heating, as shown in FIG. 9, a load receiving jig is applied so that no load is applied to the electronic component 53 mounted on the back side of the substrate 42 of the PCB 40. 54 is disposed on the back side of the substrate 42, and the upper surface of the support portion 54 a of the load receiving jig 54 is in contact with and supported by the back surface of the substrate 42.
Note that the load receiving jig need not be used when the load at the time of connection is received by the substrate 42 and the electronic components on the back side are not affected by the load.

  When the load receiving jig 54 is used, if the pressure applied to the anisotropic conductive film increases and the compressive load applied to the substrate 42 increases, the support portion 54a increases the strength of the load receiving jig 54. Needs to be thick and have a large protrusion. However, when the support portion 54a of the load receiving jig 54 is thickened, the occupied area of the support portion 54a of the load receiving jig 54 increases, but wiring conductors are formed on the back surface of the substrate 42 with high density, It is difficult to secure a space where the electronic component 53 is mounted, and the substrate 42 needs to be enlarged.

As described above, when the compressive load applied to the substrate 42 is increased, the substrate 42 is inevitably thick and large. However, in the anisotropic conductive film 20 of the present invention, as described above, the insulating resin film 21 is used. The conductive portion 23 penetrating in the thickness direction is provided so that the conductive portion protrudes from the surface of the insulating resin film 21 and is also exposed to the outer surface of the adhesive resin layer 22 on the surface of the insulating resin film 21. The pressure applied during bonding can be reduced, and as a result, the compressive load applied to the substrate 42 can be lowered.
Therefore, even when the load receiving jig 54 is disposed on the back surface of the substrate 42, the pressure resistance strength of the load receiving jig 54 can be reduced, and the support portion 54a of the load receiving jig 54 can be thinned. An increase in the area of 42 can be suppressed.

  As described above, in the printed circuit board module 100, the electrical connection portions connected by the anisotropic conductive film 20 exist at a large number of places P1 to P11, and the thickness of the substrate 42 in the connection portions of these anisotropic conductive films 20 is present. If the increase in the height and the area can be suppressed, the entire printed circuit board module 100 can be further downsized.

  The fourth embodiment is a printed circuit board module built in a mobile phone device. However, even when applied to a portable electronic device such as a digital camera, a video camera, a portable audio player, and a portable DVD player, the miniaturization is promoted. can do.

  In addition, the said embodiment is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

The wiring board connection body of 1st Embodiment of this invention is shown, (A) is a perspective view of a manufacturing process, (B) is sectional drawing of a length direction, (C) is sectional drawing of the width direction. An anisotropic conductive film is shown, (A) is a perspective view, (B) is an AA sectional view. (A)-(F) are drawings which show the manufacturing method of an anisotropic conductive film. The wiring board which consists of FPC is shown, (A) is a perspective view, (B) is a BB sectional drawing, (C) is a CC sectional view. (A)-(C) are drawings which show the modification of 1st Embodiment. It is sectional drawing of the anisotropic conductive film of 2nd Embodiment. (A) (B) is sectional drawing of the anisotropic conductive film of 3rd Embodiment. It is drawing which shows the printed wiring board module of 3rd Embodiment. It is a principal part enlarged view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wiring board connector 20 Anisotropic conductive film 21 Insulating resin film 22 Adhesive resin layer 23 Conductive part 24 Mask film 30 (30-1 to 30-6) Flexible printed wiring board (FPC)
32 Conductor 40 (40-1 to 40-5) Rigid printed wiring board (PCB)
42 conductor 53 electronic component 100 printed wiring board module

Claims (12)

An insulating resin film having through-holes in the thickness direction formed at intervals and having adhesiveness on both sides in the thickness direction;
A conductive portion that penetrates into each through hole and is exposed at both end openings;
The said conductive part is an anisotropic conductive film which conduct | electrically_connects the conductor arrange | positioned facing both the side surfaces of the thickness direction of the said insulating resin film.   The anisotropic conductive film according to claim 1, wherein the conductive portion protrudes from at least one surface side of the insulating resin film.   3. The anisotropy according to claim 1, wherein the conductive portion is formed of at least one conductive material selected from solder, solder paste, solder plating, other metal plating, or conductive resin paste. Conductive film.   The adhesive resin layer is provided on one surface or both surfaces of the insulating resin film, and the melt viscosity when the adhesive resin layer is heated is lower than the melt viscosity when the insulating resin film is heated. The anisotropic conductive film of any one of thru | or 3 thru | or 3.   The anisotropic conductive film according to claim 4, wherein the adhesive resin layer contains a thermoplastic resin as a main component. A method for producing an anisotropic conductive film according to any one of claims 1 to 5,
Laminating a mask film having an opening at a corresponding position with the through hole of the insulating resin film, or providing a through hole after laminating the insulating resin film and the mask film,
Next, a conductive part is formed by filling the through hole with a conductive material,
Then, the said mask film is peeled, The manufacturing method of the anisotropic conductive film characterized by the above-mentioned.   The method for producing an anisotropic conductive film according to claim 6, further comprising a step of providing an adhesive resin layer, wherein the adhesive resin layer is provided after the mask film is peeled off.   It is a wiring board which makes a connection part the some conductor wiring provided at intervals, Comprising: It has the anisotropic conductive film of any one of Claims 1 thru | or 5 on the surface of the said connection part. Wiring board characterized by A first wiring board having a plurality of conductor wirings provided at intervals as a first connection part, and a second wiring board having a plurality of conductor wirings provided at intervals as a second connection part. A connected body,
The wiring board connection, wherein the first connection portion and the second connection portion are electrically connected by the anisotropic conductive film according to any one of claims 1 to 5. body. The first wiring board is a flexible printed wiring board (FPC), and the second wiring board is a hard printed wiring board (PCB).
The wiring board connector according to claim 9, wherein a peel strength between the FPC and the PCB at 100 ° C. is 500 g / cm or less.   An electronic component is mounted on at least one of the first wiring board and the second wiring board of the wiring board connector according to claim 9 or 10.   An electronic device incorporating the wiring board module according to claim 11.

Images