JP2973782B2 - TAB film carrier and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TAB film carrier and a method for producing the same, and more particularly to a film carrier excellent in bending mountability.

[0002]

2. Description of the Related Art In recent years, in the mounting of semiconductors such as ICs, T
The AB (Tape Automated Bonding) method has been actively used as a method suitable for reducing the thickness, increasing the number of pins, and reducing the size of a package.

Generally, a film carrier used in the TAB system is a base film having a sprocket hole 3 for feeding a film, a device hole 4 for disposing elements, an outer lead hole 5 and the like as shown in FIGS. 1 is laminated with a copper foil via an adhesive 2. This copper foil is etched by photo-etching,
After forming a desired lead pattern including an inner lead 7 for bonding to an electrode of the C element and outer leads 8a and 8b for connection to an external substrate, the lead surface is plated.

[0004] In the TAB method manufactured in this manner, three-dimensional mounting can be performed by folding the tape utilizing the flexibility of the tape, and a lead pattern is formed on the tape to form a circuit board. It has features such as being able to be used as a mixed integrated circuit.

One of the applications utilizing the features of this TAB method is
One is a driving element of a liquid crystal panel used for a display device such as an OA device. With the demand for miniaturization and higher density of the device, a method of folding and mounting a TAB film carrier as shown in FIG. 6 has been used to reduce the mounting area of the driving element at the periphery of the liquid crystal substrate.

In the case of a film carrier used for the liquid crystal driving TAB, one of the outer leads 8a for connecting an output signal is provided on one side, and the outer lead 8b for connecting an input signal is provided on the other side.
Are formed, and the outer leads 8 for connecting output signals are formed.
“a” is opposed to an electrode formed on a peripheral portion of a liquid crystal substrate 11 on which a liquid crystal 13 is mounted, and is connected via an anisotropic conductive adhesive 10. It is mounted by soldering to the board terminals.

In particular, in the film carrier used in this type of mounting method, bending slits 6 and 6 are previously provided in bending portions 15 and 15 of the base film 1 in order to facilitate bending, and leads are formed. In general, only 14 is bent.

However, when only the lead 14 is bent, the slit opening 6, which is a bent portion,
Since there is no base film 1 at the position 6, there is a problem that mechanical stress at the time of mounting and stress due to thermal cycling and the like are concentrated on the thin lead, and cracks and breakage of the lead are likely to occur.

As a countermeasure, a method of reducing the film thickness of a bent portion by a chemical etching method, a laser processing, a cutting process, or the like without using a slit opening as a through hole (for example, JP-A-4-91450) A method has been proposed in which a liquid resin is applied to the inside of a slit opening formed as a through-hole and cured (for example, Japanese Patent Application Laid-Open No. 4-162542). In addition, a method of reducing the thickness of the entire base film to a thickness that can be bent is also conceivable.

[0010]

However, the above-mentioned prior art has the following disadvantages.

(1) The method of reducing the thickness of the film at the bent portion or applying a resin in the opening to cure the resin requires special special processing equipment. Degree, low productivity.

(2) In the method in which the entire base film is thinned to a thickness at which the base film can be bent, the strength of the base film is reduced, so that it is difficult to handle the film carrier during manufacture and mounting, and the dimensional accuracy is reduced. Not.

An object of the present invention is to provide a novel TAB film carrier excellent in bending mountability and reliability by solving the above-mentioned problems of the prior art by forming the base film into two layers. It is in.

It is another object of the present invention to provide a method for producing a TAB film carrier which can be produced by ordinary processing equipment and has excellent processability and productivity.

[0015]

According to the TAB film carrier of the present invention, a lead is formed on a base film, and a bent opening is formed in a base film portion corresponding to a bent portion of the lead. TA to be bent at position
In the film carrier for B, the base film has a two-layer structure of a first base film on the lead pattern side and a second base film on the side opposite to the lead pattern side, and is bent only on the second base film. It is provided with an opening for use.

The first and second base films used in the present invention may be any film material having flexibility, heat resistance, insulation and the like, for example, polyimide, polyester and the like. In particular, when heat resistance and dimensional stability are required, a polyimide film is preferable.
In addition, the first base film is designed to ensure bendability,
It is desirable to use one having a thickness of 25 μm or less.

Further, according to the method for producing a TAB film carrier of the present invention, a lead is formed on a base film, and a bending opening is formed in a base film portion corresponding to a bent portion of the lead. TA to be bent and used
In the method for manufacturing a film carrier for B, an adhesive is applied to both surfaces of the insulating film to form a first base film, and a second base film is formed by forming a bending hole in the insulating film. After laminating the first base film on the second base film via the adhesive, a common opening excluding the bending opening is formed in the first and second base films. After laminating a metal foil on the base film 1 via the adhesive, leads are formed.

[0018]

According to the TAB film carrier of the present invention, the base film has a two-layer structure of a first base film on the lead pattern side and a second base film on the side opposite to the lead pattern. An opening for bending is provided only in the second base film. Therefore, when the lead of the bent portion is supported by the first base film, thereby bending the TAB film carrier,
Stress concentration on the lead pattern can be reduced, and bending resistance can be greatly improved.

In the method for producing a TAB film carrier according to the present invention, the second base film, in which the opening for bending is press-formed in advance, is simply laminated on the first base film. Since the opening for use can be provided only in the second base film, no special dedicated processing equipment is required, and workability is facilitated.

[0020]

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

(Embodiment) FIG. 2 is a plan view of a TAB film carrier of this embodiment, and FIG. 3 is a sectional view taken along line AA 'of FIG. In the TAB film carrier of the present embodiment, as shown in FIGS. 2 and 3, the base film 1 includes a first base film 1a for supporting a lead 14 made of copper foil by bonding with an adhesive 2, and a second base film 1a. 1 base film 1a
Base film 1b adhered with adhesive 2 '
And a two-layer structure. The device hole 4 and the outer lead hole 5 penetrate the first and second base films 1a and 1b. The bending slit openings 6 ', 6' formed in the base film portion corresponding to the bent portion of the lead 14 are opened so as to penetrate only the second base film 1b, and the bent portion of the lead 8a is formed. Fifteen, one
5 is supported by the first base film 1a.

The TAB film carrier having the above structure is manufactured as follows. First, thickness 50μm, width 35m
A second base film 1b is formed by press-piercing a sprocket hole 3 and bending openings 6 ', 6' in a m-polyimide film. Here, the shape of the opening 6 ′ for bending was a slit shape, the opening width was 0.6 mm, and the number was 2.

Next, a first base film 1a made of a polyimide film having a thickness of 25 μm and a width of 26 mm coated with epoxy resin adhesives 2 and 2 ′ having a thickness of 10 μm on both sides.
Is laminated on one side of the second base film 1b. Thereby, the total thickness of the base film is set to a normal value of 75 μm. After lamination, desired openings including the device hole 4 and the outer lead hole 5 are provided in the first and second base films 1a and 1b in common by press punching.

Next, an electrolytic copper foil having a thickness of 35 μm and a width of 26 mm is laminated on the first base film 1 a via an adhesive 2. Then, the copper foil is etched by a photo-etching method to form a lead pattern including the inner leads 7 and the outer leads 8a and 8b, and a TAB film carrier having a plan shape shown in FIG. 2 and a cross-sectional structure shown in FIG. obtain.

FIG. 1 is a cross-sectional view in which the TAB tape carrier is bent to mount a driving element of a liquid crystal panel. The output signal connection outer lead 8a is opposed to an electrode formed on the periphery of the liquid crystal substrate 11 on which the liquid crystal 13 is mounted, and is connected via an anisotropic conductive adhesive 10. The input signal connection outer lead 8b is It is mounted by soldering to an external board terminal on the printed board 12. In the bent portions 15 of the base film 1 provided with the slit slits 6 for bending, the leads 14 are bent together with the first base film 1a. Supported by

In FIG. 1, the lead 14 is bent inward and the base film is bent outward, but the lead may be bent outward and the base film may be bent inward.

Comparative Example As a comparative example, a polyimide film having a thickness of 75 μm is used as a base film having a single-layer structure, and has the same planar shape as that of the example, and has a slit 6 for bending that penetrates the base film. 4. A film carrier for TAB having the same structure as the conventional one shown in FIG. 5 was prepared.

(Experimental Results) With respect to the two types of film carriers obtained in the above Examples and Comparative Examples, a lead bending test (bending curvature of 0.1 mm) was performed at the bent portion at the slit opening position.
5 mm, repeated bending at a bending angle of 90 °).
In the comparative example in which the bent portion was only a copper foil lead, the lead was broken after 20 to 30 times, whereas in the film carrier of the example in which the lead was supported by the first base film, the lead was cut even after bending 100 times or more. No bending occurred, indicating excellent bending resistance.

As described above, according to this embodiment, since the lead of the bent portion is supported by the flexible first base film, the lead at the time of mounting can be provided without impairing the bendability. Is prevented from being concentrated, and the bending resistance can be greatly improved. Also, since the first base film is laminated on the second base film having the opening for bending formed by press punching to reinforce the bent portion without impairing the bendability, the base of the bent portion is formed. Compared to a method of thinning a film by chemical etching or mechanical processing, a special device and process are not required, and the film can be manufactured by a conventional film carrier manufacturing facility, which is very economical.

In the above-described embodiment, the case where the width of the slit opening is 0.6 mm, the number of the slits is 2 and the width of the first base film is smaller than the width of the second base film has been described. There is no limitation, and the size and number of slit openings can be arbitrarily set according to the mounting form on the device. Also,
By forming the width of the first base film to be the same as the width of the second base film, it is possible to improve the film strength of the sprocket hole portion and improve the handleability.

[0031]

As is clear from the above description, the following effects can be obtained according to the TAB film carrier of the present invention.

(1) According to the film carrier according to the first aspect, the base film has a two-layer structure, the opening for bending is provided in the second base film, and the lead of the bent portion is formed in the first base film. Since it is supported by the base film, stress concentration on the lead during mounting is reduced without impairing the bendability, and reliability and bend resistance can be greatly improved.

(2) According to the TAB film carrier of the second aspect, the thickness of the first base film is 25
Since the polyimide film having a thickness of μm or less is used, sufficient bendability can be ensured, and the requirements for heat resistance and dimensional stability can be sufficiently satisfied.

(3) According to the method for manufacturing a TAB film carrier according to the third aspect, the second base film having the base film having a two-layer structure and the opening for bending formed in advance is used as the first base film. Since it is laminated on the film, it does not require any special equipment or process compared to the conventional method of thinning the bent part of the one-layer structure base film by chemical etching or mechanical processing. Manufacturing by a carrier manufacturing facility is enabled, and workability and productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a mounting state of a TAB film carrier according to an embodiment of the present invention.

FIG. 2 is a plan view showing a TAB film carrier according to an embodiment of the present invention.

FIG. 3 is a sectional view taken along line AA ′ of FIG. 2;

FIG. 4 is a plan view showing a conventional TAB film carrier.

FIG. 5 is a sectional view taken along line AA ′ of FIG. 4;

FIG. 6 is a cross-sectional view showing a mounting state using a conventional TAB film carrier.

[Explanation of symbols]

 Reference Signs List 1 base film 1a first base film 1b second base film 2, 2 'adhesive 3 sprocket hole 4 device hole 5 outer lead hole 6, 6' slit opening for bending 7 inner lead 8a, 8b outer lead 9 for connection IC chip 10 Anisotropic conductive adhesive 11 Liquid crystal substrate 12 Printed circuit board 13 Liquid crystal

Claims (3)

(57) [Claims] 1. A TAB which is formed by forming a lead on a base film, forming a bending hole in a base film portion corresponding to a bent portion of the lead, and bending the lead at the opening position.
In the film carrier for use, the base film has a two-layer structure of a first base film on the lead pattern side and a second base film on the side opposite to the lead pattern side, and the folding is performed only on the second base film. A film carrier for TAB, characterized by having an opening for bending. 2. The method according to claim 1, wherein the first base film has a thickness of 25 μm.
The film carrier for TAB according to claim 1, which is the following polyimide film. 3. A TAB which is formed by forming a lead on a base film, forming a bending opening in the base film corresponding to the bent portion of the lead, and bending the lead at the opening position.
In the method for producing a film carrier for use, an adhesive is applied to both sides of an insulating film to form a first base film, and a bending opening is formed in the insulating film to form a second base film. After laminating the first base film on the second base film via the adhesive,
Forming a common opening except for the opening for bending in the first and second base films, laminating a metal foil on the first base film via the adhesive, and then forming a lead. A method for producing a TAB film carrier.