JPH1173821A - Anisotropic conductive film and connection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of short circuit caused by conductive foreign matters by dispersing a cylindrical conductive particle in which a first insulating film for constituting stacking structure together with a conductive magnetic film is arranged on the outside in a thermosetting resin binder. SOLUTION: A conductive magnetic film 13 is formed by plating on the surface of a lead (a first electrode) 2 on a base film (a first insulating member) 1, and the whole surface is covered with an insulating film 9. A conductive magnetic film 14 is formed by plating on the surface of a panel terminal (a second electrode) 6 on base glass (a second insulating member) 5, and the whole surface is covered with an insulating film 10. When the lead 2 and the panel terminal 6 are connected through a conductive particle 15, even if conductive foreign matters 8 exist, the contact of the lead 2 with the panel terminal 6 is prevented by the insulating films 9, 10. Part, which is taken in the inside of the cylinder of the conductive particle 15, of the conductive foreign matters 8 and part remaining on the outside are insulated by an insulating shell 12. Accordingly, the short between the lead 2 and the panel terminal 6 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anisotropic conductive film and a connection method, and more particularly, to a TFT having a liquid crystal driving IC mounted thereon.
The present invention relates to an anisotropic conductive film used for connecting a CP to a liquid crystal panel and a connection method.

[0002]

2. Description of the Related Art At present, a flexible printed circuit board (hereinafter, referred to as T) having a liquid crystal display panel and a liquid crystal driving IC mounted thereon.
CP (Tape Carrier Package (Tape ca
For example, an anisotropic conductive film (hereinafter, referred to as ACF) is used to connect two electronic components or an electronic device (hereinafter, simply referred to as an electronic device).

[0005] As shown in FIG. 5 (a), panel terminals 6 are formed on a base film 1 and a base glass 5 in which leads 2 are arranged at equal intervals, and an insulating film 7 is formed thereon.
And a terminal (not shown) heated on the upper surface of the TCP base film 1 with the ACF in which the conductive particles 4 are dispersed interposed between the tape-shaped thermosetting resin binder 3 and the terminal portion of the panel formed with FIG. 5
As shown in (b), the leads 2 are brought into contact with the panel terminals 6 via the conductive particles 4. By cooling to room temperature, the resin binder 3 is cured and the TCP and the terminal of the panel are joined.

When the width and spacing of electrodes (leads and panel terminals) decrease with the increase in the number of pixels of a liquid crystal display device, the number of conductive particles connecting the leads and the panel terminals decreases. If the conductive particles are dispersed at a high density in order to prevent the connection resistance from increasing, short-circuit failure between the electrodes is likely to occur.

There are various conventional examples proposed to solve such a problem.

A first conventional example described in Japanese Patent Application Laid-Open No. 6-69643 discloses a method in which conductive particles are made into a magnetic material, and when heated and pressed, a magnetic field is applied from the outside so that the conductive particles are directed in the direction of the magnetic field. By arranging them in contact with each other and arranging them apart from each other in a direction orthogonal to the magnetic field, it is intended to realize good connection and prevention of short circuit failure.

A second conventional example described in Japanese Patent Application Laid-Open No. Hei 5-206204 discloses a method in which conductive particles are formed into a magnetic material, and a magnetic film is formed on a panel terminal and magnetized, thereby forming a magnetic layer on the panel terminal. It is intended to realize good connection by adsorbing conductive particles to a body film.

[0008] These relate to an anisotropic conductive film in which conductive particles are randomly dispersed in a resin binder.

On the other hand, as disclosed in Japanese Patent Application Laid-Open No. 63-86322, a column-shaped conductor is electrically connected to the insulating adhesive material in the thickness direction of the layer when pressed and insulated in the in-plane direction. ACF embedded in array (third conventional example)
Also, as disclosed in Japanese Patent Application Laid-Open No. 63-94504, an ACF (fourth conventional example) in which a cylindrical conductive material is filled into a cylindrical straight hole opened in an insulating thin film to form a columnar conductor is also known. Have been.

[0010]

The conventional example described above can prevent a short-circuit failure due to an increase in the number of pixels. However, as shown in FIG. It is not effective for the problem that adjacent electrodes are electrically connected and short-circuited. When a connection is made using an ACF in a state where a conductive foreign substance is present between adjacent electrodes, even if the adjacent electrodes can be prevented from being directly connected to each other by the conductive foreign substance, the adjacent electrodes can be directly connected to each other. This is because it is unavoidable that the conductive particles or the columnar conductors are short-circuited by the conductive foreign matter.

An object of the present invention is to provide an anisotropic conductive film and a connection method capable of preventing occurrence of short-circuit failure due to conductive foreign matter.

[0012]

The anisotropic conductive film of the present invention has a laminated structure including a conductive magnetic film and a first insulating film, and has a cylindrical shape in which the first insulating film is disposed outside. Are dispersed in a thermosetting resin binder.

[0013] In this case, the end of the conductive particles may have a blade-like or saw-tooth-like shape.

Further, it is preferable that the conductive magnetic film is made of a ferromagnetic material having a Curie temperature higher than the thermosetting temperature of the resin binder.

[0015] The connection method of the present invention comprises the steps of: connecting an anisotropic conductive film having conductive particles dispersed in a thermosetting resin binder to a first electrode provided on a first insulating member; It is inserted between the second electrode provided on the member, heated and pressed to a predetermined temperature, applies a magnetic field in the thickness direction of the anisotropic conductive film, and connects the first electrode and the second electrode to each other. In the connection method for joining the first insulating member and the second insulating member by establishing electrical continuity, the conductive particles have a laminated structure including a conductive magnetic film and a first insulating film. The first
Of the first electrode or the second electrode is provided with a magnetic film on at least one of them and is covered with a second insulating film and a third insulating film, respectively. It is that it is. In this case, the second insulating film is made of a resin having a softening temperature higher than the thermosetting temperature of the resin binder, and the conductive magnetic film is made of a ferromagnetic material having a Curie temperature higher than the thermosetting temperature of the resin binder. be able to.

The ends of the conductive particles may have a blade-like or saw-tooth-like shape.

When the thermosetting resin binder is fluidized by heating, the magnetic poles of the magnetic film and / or the external magnetic field and the magnetic poles of the conductive particles and the conductive poles of the conductive particles are provided on at least one of the first electrode and the second electrode. Due to the magnetic interaction between the conductive particles, the conductive particles become the first particles provided with the magnetic film.
And / or coarsely in the vicinity of the second electrode and / or the second electrode, with their axes aligned in the direction of the external magnetic field. By applying pressure in that state, the first electrode and the second electrode are connected by conductive particles. Even if conductive foreign matter is present, the particles are separated by the cylindrical conductive particles.

[0018]

Embodiments of the present invention will now be described with reference to the drawings.

Referring to FIG. 1, an anisotropic conductive film according to an embodiment of the present invention includes a conductive magnetic film 11 and an insulating film (insulating shell 12) on a resin binder 3 attached to a carrier film 16. ), And the cylindrical conductive particles 15 having the insulating shell 12 disposed outside are randomly dispersed. Here, it is assumed that the conductive magnetic film 11 is magnetized in advance and magnetic poles of opposite polarities are formed at both ends of the cylinder. further,
It is preferable that both ends of the cylinder have a sawtooth shape (first example) as shown in the figure, or a blade shape (second example) as shown in FIG.

The resin binder 3 is, for example, an epoxy resin or an epoxy resin adhesive obtained by dispersing a curing agent in an epoxy resin in the form of a capsule protected by a reaction-inhibiting film, and may be a material usually used for TCP.

The conductive magnetic film 11 includes an Fe film, a Ni film,
A Co film or an Fe—Ni—Co alloy film is provided on the inner wall of the insulating shell 12. The Curie temperature of the conductive magnetic film 11 is set at the thermosetting temperature of the resin binder 3 (1.
00-180 ° C).

The insulating shell 12 is an insulating cylinder having a certain degree of elasticity so as not to cause plastic deformation at a predetermined temperature required for the electronic device when the electronic device is connected to and used with an anisotropic conductive film. is there.

Next, a method for connecting an electronic device using the anisotropic conductive film will be described.

As shown in FIG. 3A, an anisotropic conductive film peeled from a carrier film is disposed between the TCP and the terminal of the panel of the liquid crystal display device.

A lead film (first electrode) on a TCP base film 1 (first insulating member) has an Fe film, Ni film
A conductive magnetic film 13 such as a film, a Co film, or a Ni—Co alloy film is plated. Further, the entire surface is covered with an insulating film 9 such as a photoresist film. Magnetic film 13
Is assumed to be demagnetized in advance here.

On the surface of the panel terminal 6 (second electrode) made of a conductive film such as a Cr film on the base glass 5 (second insulating member) of the terminal portion of the panel of the liquid crystal display device, an Fe film, Ni
A conductive magnetic film 14 such as a film or an Fe—Ni—Co alloy film is plated. Further, the entire surface is covered with an insulating film 10 such as a silicon nitride film. Magnetic film 14
Is assumed to be demagnetized in advance here.

Next, a heated head (not shown) is applied to the base film 1 to apply heat and pressure.
As shown in (b), an external magnetic field Φ (substantially perpendicular to the base glass 5 and the base film 1) is applied from the terminal of the panel to the TCP. When the resin binder 3 reaches a softening temperature of 100 to 120 ° C. and becomes a fluidized state, if the conductive particles 15 are magnetized in advance, the N pole becomes TC
The south pole is drawn to the panel side and the south pole is drawn to the panel side. The magnetic film 13 of the TCP is magnetized and has an S pole on its surface. Similarly,
The magnetic film 14 of the panel is also magnetized and has an N pole on its surface. The magnetization of the conductive particles 15 also advances. Conductive particles 15
Attempt to align in the direction of the external magnetic field Φ, but repel each other in the direction perpendicular to the external magnetic field Φ. Thus, due to the interaction between the external magnetic field, the S pole of TCP, the N pole of the panel, and the conductive particles, the conductive particles 15 are aligned in the direction connecting the lead 2 and the corresponding panel terminal 6. The conductive particles 15
There is a dense distribution where the leads 2 and the panel terminals 6 are located, and a coarse distribution where the leads 2 and the panel terminals 6 are not located (0 when the density of the dispersed conductive particles is small). The conductive particles 15 are pressurized by the movement of the heated header, and the TCP insulating film 9 and the panel insulating film 10 are broken, as shown in FIG.
The leads 2 and the panel terminals 6 are connected. At this time, it is assumed that the temperature of the resin binder has risen to about 180 ° C.
Stop heating and pressurizing and cool to near room temperature. The crosslinking reaction of the thermosetting resin binder 3 further progresses during the heating up to about 180 ° C. (thermosetting treatment). Thus, the resin binder is cured and the joining of the TCP and the panel is completed. The Curie temperature of ferromagnetic materials such as Fe, Ni, and Co is
Since the temperature is higher than the thermosetting temperature, there is no possibility of losing ferromagnetism in the above processing steps. Further, since the softening temperature of the photoresist film is higher than 180 ° C., there is no problem that the shape is lost.

FIG. 4 is a schematic sectional view showing the liquid crystal display device and the TCP connected as described above.

The conductive magnetic film 11 made of conductive particles only needs to be in contact with both the magnetic films 13 and 14, but preferably, as shown in FIG. 6 respectively. The insulating shell 12 may be in contact with the insulating films 9 and 10 without forming a gap, but is preferably cut into these as illustrated.

In this figure, the leads 2 and the panel terminals 6 are connected by one conductive particle 15 in the width direction. In the case of double, a plurality of conductive particles are arranged and connected in parallel.

Although the case has been described in which the magnetic films provided on the surfaces of the leads and the panel terminals are first demagnetized, they may be magnetized in advance. At that time, the polarities of the magnetic poles on the surfaces of the respective magnetic films are set to be opposite to each other, and the direction of the resulting magnetic field and the direction of the external magnetic field Φ are made the same. Further, a magnetic film may be provided only on one of the surfaces, for example, only on the surface of the lead.

Further, the conductive particles need not be magnetized in advance.

Even if conductive foreign matter 8 is attached between adjacent leads or between panel terminals, conductive particles 15
And is insulated by the insulating shell 12, so that a short circuit can be prevented.

[0034]

As described above, according to the anisotropic conductive film and the connection method of the present invention, when the first electrode and the second electrode are connected via the conductive particles, the conductive foreign matter Is present, the contact between the conductive foreign matter and each of the first electrode and the second electrode is caused by the second electrode covering the first electrode and the second electrode.
The portion of the conductive foreign matter that is prevented by the insulating film and the second insulating film and that is captured inside the cylinder of the conductive particles (contact with the conductive magnetic film of the conductive foreign material) and the portion that remains outside Since the first and second electrodes adjacent to each other are insulated by the insulating shell outside the conductive particles, a short circuit between the first and second electrodes adjacent to each other is prevented.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an ACF according to an embodiment of the present invention.

FIG. 2 is a side view with a partially crushed cross section showing a second example of conductive particles.

3A to 3C are cross-sectional views in the order of steps, illustrating a connection method using an ACF according to an embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view showing an electronic device (liquid crystal display device and TCP) connected using an ACF according to an embodiment of the present invention.

FIG. 5A to FIG. 5D for explaining a conventional technique.
FIG. 4B is a sectional view illustrating a process order, which is separately illustrated in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 base film 2 lead 3 resin binder 4 conductive particle 5 base glass 6 panel terminal 7 insulating film 8 conductive foreign material 9 insulating film 10 insulating film 11 conductive magnetic film 12 insulating shell 13 magnetic film 14 magnetic film 15 conductive Particles 16 carrier film

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H05K 3/36 H05K 3/36 A

Claims (6)

[Claims] A cylindrical conductive particle having a laminated structure including a conductive magnetic film and a first insulating film and having the first insulating film disposed outside is dispersed in a thermosetting resin binder. An anisotropic conductive film, characterized in that: 2. The anisotropic conductive film according to claim 1, wherein the end of the conductive particles has a blade-like or saw-tooth-like shape. 3. The anisotropic conductive film according to claim 1, wherein the conductive magnetic film is a ferromagnetic material having a Curie temperature higher than the thermosetting temperature of the resin binder. 4. An anisotropic conductive film in which conductive particles are dispersed in a thermosetting resin binder is provided on a first electrode provided on a first insulating member and a second electrode provided on a second insulating member. Between the first electrode and the second electrode by applying a magnetic field in the thickness direction of the anisotropic conductive film by applying a magnetic field in the thickness direction of the anisotropic conductive film. In the connecting method for joining the first insulating member and the second insulating member, the conductive particles may have a laminated structure including a conductive magnetic film and a first insulating film. A first electrode or a second electrode provided with a magnetic film on at least one of them and covered with a second insulating film and a third insulating film, respectively; A connection method characterized in that: 5. The ferromagnetic material, wherein the second insulating film is made of a resin having a softening temperature higher than the thermosetting temperature of the resin binder, and the conductive magnetic film has a Curie temperature higher than the thermosetting temperature of the resin binder. The connection method according to claim 4, wherein the connection method is a body. 6. The connection method according to claim 4, wherein the end of the conductive particles has a blade-like or saw-tooth-like shape.