JPH07244291A - Anisotropic conductive film, liquid crystal display device and electronic printing device using the same - Google Patents

Abstract

PURPOSE:To stabilize electric interconnection among circuit boards with an anisotropic conductive film and to secure connection reliability for a long time by using a conductive plastic material as the conductive particles. CONSTITUTION:The anisotropic conductive film 3 is constituted mainly of the conductive particle 1 and an adhesive 2. The conductive particle 1 is almost a spherical particle mainly containing polythienylen vinylene(PTV) of the conductive plastic material. The adhesive 2 is made of a compound of styrene- butadiene-styrene(SBS) base, styrene-ethylene-butadiene-styrene(SEBS) base, epoxy base, acrylic base, polyester base, urethane base or the like or their mixture, and may be made of a compound of a thermoplastic, thermosetting or photosetting resin or their mixture. The conductive particles 1 are mixed and dispersed in the adhesive 2 to form the mixture into film state or may be also formed in melting state or paste state.

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 for electrical connection, a liquid crystal display device using the same, and an electronic printing device.

[0002]

2. Description of the Related Art In a conventional anisotropic conductive film, carbon (graphite) particles, metal particles such as nickel, indium, lead, tin, solder, etc. are used as conductive particles, and thermoplastic or thermal adhesive is used as an adhesive. It has been generally known that it is curable, photocurable, and some mixtures or compounds thereof, in which the conductive particles are dispersed in the adhesive. For example, it is described in JP-A-2-10316, page 2, upper right column, line 14 to lower left column, line 15 of the same page.

[0003]

However, the above-mentioned conventional technique, as shown in FIG.
ITO (Indium) on the glass substrate 106 of the panel
Electrode terminal 107 made of Tin Oxide) and TC
P (Tape Carrier Package) 10
When the terminal 105 of No. 4 was connected, the conductive particles 101 were interposed between the terminal 105 of the TCP 104 and the electrode terminal 107 to ensure a good connection state, but a plastic substrate such as polycarbonate was used as the substrate material of the panel. In the case of the liquid crystal display device used, as shown in FIG. 10, the electrode terminals 107 and the TCP on the plastic substrate 106 of the panel are used.
When the terminal 105 of 104 is connected using the anisotropic conductive film 103, the conductive particles 101 cause the electrode terminal 10 to be connected.
The crack 108 etc. generate | occur | produce on the 7 surface. 11 is shown in FIG.
The surface of the electrode terminal 107 on the plastic substrate 106 is shown by peeling off what is once connected as shown in FIG. 0, and cracks 108 are generated in a part or the whole of the part in contact with the conductive particles 101. . Such a crack 1
Due to the generation of 08, there is a drawback that electrical connection cannot be established or becomes unstable, and sufficient connection reliability cannot be ensured. This also affects the connection reliability in a liquid crystal display device or an electronic printing device using an anisotropic conductive film.

Therefore, the present invention has been made to solve the above-mentioned drawbacks, and an object of the present invention is to stabilize the electrical connection by an anisotropic conductive film between circuit boards to secure long-term connection reliability. Another object is to provide the anisotropic conductive film, the liquid crystal display device, and the electronic printing device.

[0005]

The invention according to claim 1 is
In the anisotropic conductive film that joins the circuit boards, the conductive connecting portions formed on each of the pair of circuit boards are opposed to each other, and the conductive connecting portions are interposed between the opposing terminals of the conductive connecting portions.
It is characterized in that a conductive plastic material is used as the conductive particles.

According to a second aspect of the invention, the conductive particles of the anisotropic conductive film according to the first aspect are formed by using polyphenylene vinylene (PT).
It is characterized in that a plastic material containing V) as a main component is used.

The invention according to claim 3 is characterized in that a liquid crystal driving semiconductor chip or a liquid crystal driving semiconductor chip-mounted electronic element is connected using the anisotropic conductive film according to claim 1.

According to a fourth aspect of the present invention, in the liquid crystal display device according to the third aspect, a plastic film material is used.

According to a fifth aspect of the present invention, in the electronic printing apparatus, the driving semiconductor chip or the electronic element mounted with the driving semiconductor chip is connected by using the anisotropic conductive film according to the first aspect.

[0010]

EXAMPLES Examples of the anisotropic conductive film of the present invention, a liquid crystal display device using the same, and an electronic printing device will be described below.

[Embodiment 1] An embodiment of the present invention will be described below.

FIG. 1 shows an anisotropic conductive film 3 of this embodiment.
The anisotropic conductive film 3 is mainly composed of conductive particles 1 and an adhesive 2. The conductive particles 1 are substantially spherical particles containing polyconylene vinylene (PTV), which is a conductive plastic material, as a main component. The size is about 1 μm to 20 μm. Further, the shape of the particles is not limited to a spherical shape, and may be an ellipsoidal shape, a polyhedral shape, or a fiber shape. Adhesive 2 is a styrene-butadiene-styrene (SBS) -based, styrene-ethylene-butadiene-styrene (SEBS) -based, epoxy-based, acrylic-based, polyester-based, urethane-based adhesive, etc., alone or as a mixture of two or more compounds, , Thermosetting, photocurable, alone or some mixtures or compounds thereof. The conductive particles 1 are mixed and dispersed in the adhesive 2 at a ratio of 2 to 10% by weight, and the thickness is 0.003 mm to 0.025 mm.
It is in the form of a film. Besides, it may be in the form of a solution or a paste, and can be used as an anisotropic conductive film or an anisotropic conductive adhesive.

In the conventional conductive particles obtained by subjecting relatively soft solder particles, indium lead particles, or insulating plastic particles such as polyester to conductive treatment such as Ni + Au plating, the terminals of the circuit board are fragile or have a surface condition or material or While there were problems such as cracks and peeling for the structure, by using a conductive plastic material as the conductive particles as in this example, the cracks and peeling did not occur. , Fine pitch terminals can be connected and long-term connection reliability can be secured.

[Embodiment 2] FIG. 2 is an overall view of a liquid crystal display device of the present embodiment. FIG. 3 is a view of a main part of a connection part using the anisotropic conductive film 3 of the present invention, and FIGS. 4 and 5 are cross-sectional views of the main part. This liquid crystal display device has a display screen size of 14 cm diagonal and a display capacity of 480 × 3.
The panel bases 16 and 17 having 20 dots and constituting the liquid crystal panel 4 are not glass but plastic films or plastic plates such as polycarbonate (PC) or polyether sulfone (PES) having a thickness of 80 to 500 μm. The anisotropic conductive film 3 includes six TCPs 5 each having a liquid crystal driving semiconductor chip 6 having 80 outputs on the X side, and two TCP5 having a liquid crystal driving semiconductor chips 6 having 160 outputs on the Y side. It is connected to the liquid crystal panel 4 via the. A mold 10 is provided between the liquid crystal panel 4 and the TCP 5 to reinforce and prevent moisture.

The anisotropic conductive film 3 is composed of conductive particles of polyphenylene vinylene (PTV), which is a conductive plastic material, and has a substantially spherical particle diameter of about 10 to 16 μm and a low temperature curing type epoxy resin. The adhesive resin comprises styrene ethylene butadiene styrene (SEBS) resin in an amount of approximately 50 parts and 50 parts. The anisotropic conductive film 3 is transferred to the output terminal 12 of the TCP 5 in advance, the output terminal 12 of the TCP 5 and the panel terminal 11 made of ITO of the liquid crystal panel 4 are aligned, and the anisotropic conductive film 3 is aligned. Temporarily fix using the initial adhesiveness of the film. After temporarily fixing the six TCPs 5 on the X side in this way, 130 ° C., 5 MPa,
The panel terminals 11 and T are heated and pressed under the crimping condition of 20 seconds.
The output terminal 12 of the CP 12 is electrically and mechanically connected. By the same method, two TCPs 5 on the Y side are also attached to the liquid crystal panel 4.
Is electrically and mechanically connected to the panel terminal 11. As shown in FIG. 5, in the portion where the conductive particles 1 are in contact with the panel terminal 11, a slight deformation of ITO is observed,
As shown in FIG. 6, when the connected TCP is peeled off and the surface of the panel terminal 11 is observed, a contact mark 15 due to the deformation of the ITO or the plastic base material of the panel can be seen at the portion in contact with the conductive particles. No cracks or the like of ITO were observed. In this way, a highly reliable anisotropic conductive film connection that secures a good connection even for the ITO film on the surface of a plastic film or plastic plate, which is a material that is much softer than glass Is.

X side terminal connection pitch is 0.20 mm, Y
Although the terminal connection pitch on the side is 0.18 mm, this liquid crystal display device has a moisture resistance test (60 ° C., 90% RH) of 5
Each of the reliability evaluation tests of 00 hours and 200 cycles of the thermal cycle test (−20 ° C. × 30 minutes to 60 ° C. × 30 minutes) was carried out, and in each case, sufficient reliability was secured without any problem.

[Embodiment 3] FIG. 7 is a sectional view of a main portion of a connecting portion using the anisotropic conductive film 3 in the liquid crystal display device of the present embodiment. This liquid crystal display device has a display screen size of 14 cm diagonal, a display capacity of 480 × 320 dots, and the panel base materials 16 and 17 forming the liquid crystal panel 4 are not made of glass but have a thickness similar to the second embodiment. 80-5
It is a plastic film or plate such as 00 μm polycarbonate (PC) or polyether sulfone (PES). In this embodiment, the bumps 14 of the liquid crystal driving semiconductor chip 6 are connected to the panel terminals 1 of the liquid crystal panel 4.
1 has a COG (Chip On Glass) structure in which the anisotropic conductive film 3 is connected to the input terminal 1 and the input terminal 13.

The anisotropic conductive film 3 is composed of polyphenylene vinylene (PTV) as a main component and has a substantially spherical particle size of about 2 to about 2.
A paste-like anisotropic conductive adhesive in which 5 μm conductive particles are mixed and dispersed in a low temperature curing type epoxy resin in an amount of 2 to 6% by weight. First, the anisotropic conductive film 3 is applied to the panel terminals 11 and the input terminals 13 of the panel at approximately the same positions as the portions where the liquid crystal driving semiconductor chips 6 are mounted by using a dispenser to a film thickness of about 10 μm. . Next, the bumps 14 of the semiconductor chip and the corresponding panel terminals 11 and input terminals 13 were aligned and connected with a thermocompression bonding tool. Thermocompression bonding conditions are 130 ℃,
It was conducted at 0.5 MPa for 20 seconds. When the connection state was observed on the ITO surface, contact traces were observed at the contacting portions of the conductive particles, but there was no defect such as ITO cracking, and it is speculated that a good connection state was secured.

This liquid crystal display device has the same display capacity and size as the second embodiment, and uses the same liquid crystal driving semiconductor chip. Here, the material of the bumps 14 of the semiconductor chip is Au. Connection bump pitch is 100-180 μm
However, the moisture resistance test (60
Each reliability evaluation test of 500 cycles at ℃, 90% RH) and 200 cycles of thermal cycle test (-20 ° C x 30 minutes to 60 ° C x 30 minutes) was conducted, but sufficient reliability was secured without any problems. It had been.

[Embodiment 4] FIG. 8 shows an anisotropic conductive film 3 in the electronic printer (thermal printer head) of this embodiment.
It is sectional drawing of the principal part of the connection part which used. In this embodiment, the TCP 22 equipped with the semiconductor chip 21 for driving the thermal printer head is connected to the N of the thermal printer head 24.
Anisotropic conductive film 3 is applied to terminal 25 of the thermal printer head which is metal-treated by i + Au plating, Cr + Al plating or the like.
It has a structure that is connected using.

The anisotropic conductive film 3 is mainly composed of polyconylene vinylene (PTV), which is a conductive plastic material, and contains epoxy resin in an amount of 5 to 15% by weight. Is a paste-like anisotropic conductive adhesive obtained by mixing and dispersing 2 to 6% by weight of the conductive particles in a low temperature curing type epoxy resin. This anisotropic conductive film 3
First, the TC on which the thermal printer head driving semiconductor chip 21 of the terminal 25 of the thermal printer head is mounted
Application is performed at a position approximately the same as the portion to which the output terminal 23 of P22 is connected by using a dispenser so as to have a film thickness of about 18 μm. Next, the output terminal 23 of the TCP 22 and the corresponding terminal 25 of the thermal printer head were aligned and connected with a thermocompression bonding tool. The thermocompression bonding conditions are
It was carried out at 130 ° C., 0.5 MPa, 20 seconds. Since it can be crimped under low temperature and low pressure conditions in this way, the connected terminal 25
There are no defects such as cracks or peeling on the metal-treated surface of
A good connection was secured. A mold 10 is applied to the exposed portion of the terminal 25 of the thermal printer head to reinforce and prevent moisture.

With respect to this electronic printer, a humidity resistance test (6
Each reliability evaluation test of 0 ° C., 90% RH) for 1000 hours and 1000 cycles of cooling / heating cycle test (−20 ° C. × 30 minutes to 60 ° C. × 30 minutes) was performed. It was secured.

[0023]

According to the first aspect of the present invention, by using the conductive plastic material as the conductive particles of the anisotropic conductive film, a good connection state can be secured even under low temperature and low pressure connection conditions. There is no occurrence of defects such as cracks or peeling of the terminals, the electrical connection between the circuit boards is stabilized by the anisotropic conductive film, and long-term connection reliability can be secured.

According to the third aspect of the present invention, since the anisotropic conductive film according to the first aspect is used for electrical connection, a liquid crystal display device having high connection reliability can be obtained.

According to the invention described in claim 5, since the electrical connection is made by using the anisotropic conductive film according to claim 1, an electronic printer having high connection reliability can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing another embodiment of the present invention.

FIG. 3 is a diagram showing a main part of another embodiment of the present invention.

FIG. 4 is a diagram showing a cross section of a main part of another embodiment of the present invention.

FIG. 5 is a view showing a cross section of a main part of another embodiment of the present invention.

FIG. 6 is a diagram showing a main part of another embodiment of the present invention.

FIG. 7 is a view showing a cross section of a main part of another embodiment of the present invention.

FIG. 8 is a diagram showing a cross section of a main part of another embodiment of the present invention.

FIG. 9 is a view showing a cross section of a main part of a conventional example.

FIG. 10 is a view showing a cross section of a main part of a conventional example.

FIG. 11 is a diagram showing a main part of a conventional example.

[Explanation of symbols]

1. Conductive particles 2. Adhesive 3. Anisotropic conductive film 4. Liquid crystal panel 5. TCP (Tape Carrier Pack)
e) 6. Liquid crystal driving semiconductor chip 7. X-side bus board 8. Y-side bus board 9. Tape wire 10. Mold 11. Panel terminal 12. Output terminal 13. Input terminal 14. Bump 15. Contact mark 16. Panel base material 17. Panel base material 21. Semiconductor chip for driving thermal printer head 22. TCP 23. Output terminal 24. Thermal printer head 25. Terminals of thermal printer head 26. Substrate 27. Mold 28. Solder 101. Conductive particles 102. Adhesive 103. Anisotropic conductive film 104. TCP 105. Terminal 106. Liquid crystal display panel 107. Electrode terminal 108. crack

Claims (5)

[Claims] 1. An anisotropic conductive film for bonding circuit boards to each other, with conductive connection portions formed on each of a pair of circuit boards facing each other and interposed between opposing terminals of the conductive connection portions, An anisotropic conductive film using a conductive plastic material as conductive particles. 2. The anisotropic conductive film according to claim 1, wherein a plastic material containing polyphenylene vinylene (PTV) as a main component is used as the conductive particles of the anisotropic conductive film. 3. A liquid crystal display using an anisotropic conductive film, wherein a liquid crystal driving semiconductor chip or an electronic element mounted with a liquid crystal driving semiconductor chip is connected using the anisotropic conductive film according to claim 1. apparatus. 4. The liquid crystal display device according to claim 3, wherein a plastic film material is used and an anisotropic conductive film is used. 5. An electronic printing apparatus, wherein a driving semiconductor chip or an electronic element mounted with a driving semiconductor chip is connected by using the anisotropic conductive film according to claim 1.