JPH08306741A - Film carrier for tab and its production - Google Patents

Abstract

PURPOSE: To provide film a carrier for TAB in which no restriction is put on the shape of slit being made at a bending part and the reliability is enhanced by improving the bending characteristics. CONSTITUTION: A reinforcing film 4 is applied to the rear of a flexible insulating basic material film 1 having the surface formed with a wiring pattern 2. The reinforcing film 4 is removed partially from the part 12 to be bent at the time of mounting thus making a slit 5. A material excellent in flexibility is employed for the insulating basic material film 1 and a material having sufficiently high mechanical strength is selected for the reinforcing film 4. A polyimide resin is preferably employed as these materials.

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 in which a wiring pattern is formed on the surface of a base film and a method for manufacturing the same, and more particularly to a TAB film carrier which requires bending during mounting.

[0002]

2. Description of the Related Art In recent years, a film carrier type semiconductor mounting technique called TAB has been attracting attention along with IC / LSI and the like. TAB is Tape Automa
Ted Bonding is an abbreviation of ted Bonding, and its features include high-efficiency batch bonding, ultra-fine pitch, and flexibility of bending board mounting. It is often used for liquid crystal drivers. ing.

The TAB film carrier mainly has a structure in which a metal wiring pattern is adhered to an insulating base film via an adhesive. The typical manufacturing method is 3
A guide hole called a perforation hole or an insulating base film with an adhesive having a width of 5 mm or 70 mm,
A device hole for bonding to a semiconductor chip, an outer hole for joining a substrate of outer leads, and the like are processed by press punching. Next, a conductive metal foil such as a copper foil is heat-bonded to this adhesive base film with an adhesive.
Then, a photosensitive organic resist paint is applied on the metal foil surface, the wiring pattern is baked and developed, and the wiring pattern is formed on the insulating base film along the resist pattern by an etching method. Further, if necessary, a solder resist for pattern protection is formed on the wiring pattern, and finally surface treatment such as tin plating, gold plating, solder plating is performed to complete the process.

The above-mentioned TAB film carrier is often folded and mounted on a liquid crystal panel or the like by taking advantage of its flexibility, and such a TAB film carrier has a base material at its bent portion. There is a film in which a slit is provided to improve bendability. However, when bent at this slit portion, the bending radius becomes small at the edge of the slit and the wiring pattern is often broken.

In order to prevent the breakage of the wiring pattern at the time of bending, a flex resin-filled type TAB film carrier has been proposed. As shown in FIG. 4, this is the insulating base film 21 at a portion that needs to be bent at the time of mounting.
The bending slit 24 formed in the above is filled with a flexible resin 25, which prevents the wiring pattern 22 from being bent at the edge of the slit 24 at the time of bending, and the bending is shared by the entire slit. The aim is to have a large radius.

[0006]

However, even in the flex resin-filled type TAB film carrier,
There are some manufacturing constraints. Flex resin is usually
The slit is filled by printing, but the slit width is 1.
There is no problem in the range of 0 to 3.0 mm, but it is difficult to fill when the slit has a narrow width of 1 mm or less. On the contrary, if the slit has a wide width of 3 mm or more, it is very difficult to fill the flex resin with a sufficient thickness to ensure bendability. In addition, it is difficult to uniformly fill the slits, and defects such as pinholes in the flex resin and poor adhesion with the conductor cannot be avoided.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, to provide a TAB film carrier which has no slit shape restriction, has good bending characteristics and can be improved in reliability. Another object of the present invention is to provide a method for manufacturing a TAB film carrier which does not require printing and is easy to manufacture.

[0008]

A film carrier for TAB of the present invention has a reinforcing film attached to the back surface of a flexible insulating substrate film having a wiring pattern formed on the surface thereof, and is folded at the time of mounting the reinforcing film. A slit is formed at a bent portion that requires bending.

Further, the method for producing a TAB film carrier of the present invention comprises a flexible insulating base film and a reinforcing film for reinforcing the perforation hole,
Necessary holes such as device holes and outer holes are formed in the same size and arrangement, and the reinforcing film is further provided with slit-shaped holes at the bent portions that require bending at the time of mounting. , A wiring pattern is formed on the surface of the insulating base film on the side opposite to the back side where the reinforcing film is pasted, by aligning the necessary holes such as outer holes with each other Is.

[0010]

When the TAB film carrier is bent at the time of mounting, since the bent portion is made of a flexible insulating base material film, it is flexible and can have a large radius of curvature. It is possible to prevent breakage of the wiring pattern running on the bent portion.

Further, since the slit formed at the bent portion is lined with a flexible insulating base material film, it is not necessary to fill the slit with flex resin,
Therefore, there is no restriction on the slit width.

For the base film, a material and a thickness that are highly flexible when bent are selected. The material is preferably polyimide resin, for example. Further, the thickness is closely related to the width of the slit formed in the portion requiring bending, but the thickness is made sufficiently thin. For example, in the case of a narrow slit having a slit width of less than 1 mm, about 5 to 20 μm is preferable. 1
In the case of a wide slit of mm or more, a thickness of about 15 to 50 μm is preferable in consideration of strength as an insulating base film.

Further, as the reinforcing film, a material and a thickness which can sufficiently secure the strength as a film material are selected. The material is preferably polyimide resin, for example. Also, the thickness is
The total thickness of the insulating base film including the adhesive is preferably 75 μm to 150 μm, although it depends on the use of the film carrier formed by attaching the insulating base film. If the total thickness is 75 μm or less, the mechanical strength as a film carrier cannot be maintained, and
If it is more than m, flexibility becomes poor and the merit of the film carrier is lost.

[0014]

Embodiments of the present invention will be described below. 1A and 1B show a TAB film carrier of the present embodiment. FIG. 1A is a perspective view, and FIG. 1B is a sectional view taken along the line AB.

In the film carrier for TAB, a reinforcing film 4 for reinforcing the strength of the insulating base film 1 is provided on the back surface of the flexible insulating base film 1 having the wiring pattern 2 attached to the front surface with an adhesive 3. It is attached with an adhesive 6. The insulating base film 1 and the reinforcing film 4 are provided with a perforation hole 7, a device hole 8 and an outer hole 9 in common. The wiring pattern 2 has an inner lead 10 projecting into the device hole 8 located substantially in the center, and outer leads 11 extending left and right thereof.

This TAB film carrier has a bent portion 12 that needs to be bent at the time of mounting, and the portion 12 is usually located in the middle of the extending outer lead 11. The reinforcing film 4 at the bent portion 12 is partially removed to form the slit 5 as illustrated.

The insulating base film 1 has a thickness of, for example, 50 μm.
m polyimide resin, Kapton V (registered trademark) manufactured by Toray DuPont Co., Ltd. as a trade name, and the wiring pattern 2 is adhered to the surface of the insulating base film 1 through an adhesive 3 having a thickness of 19 μm. There is. The reinforcing film 4 is made of a polyimide resin having a thickness of 50 μm, and Upilex S (registered trademark) manufactured by Ube Industries, Ltd. is used as a trade name. A slit 5 having a width of 3 mm is formed on the reinforcing film 4 at the bent portion 12. The reinforcing film 4 is adhered to the back surface of the insulating base film 1 with an adhesive 6 having a thickness of 19 μm. The adhesives 3 and 6 are made of polyimide resin.

As shown in FIG. 2, the TAB film carrier constructed as described above has a semiconductor chip 13 mounted on the inner leads 10 protruding in the device hole 8 and a liquid crystal 14 mounted on the outer leads 11, and the like. Is bent at the slit 5 and used.

Here, in order to confirm the performance of the TAB film carrier of this embodiment, the bending resistance of the outer lead 11 at the slit 5 portion was evaluated. The evaluation of the fold resistance is indicated by the number of folds until the outer lead is broken when a 90 ° both-sides bending test is performed with a load of 100 g. For comparison, the conventional flex resin-filled TAB film carrier shown in FIG. 4 was also tested. The TAB film carriers used in the tests all had the same wiring pattern (folded outer lead width 80
μm) and the slit width is the same (1.0
mm).

As a result, it was found that the fold resistance of this example was 200 times or more compared to 100 times of the conventional example, which was more than twice as good as that of the conventional example.

Next, a method of manufacturing the TAB film carrier of this embodiment described above will be described. As shown in FIG. 3, first, a perforation hole, a device hole 8 and an outer hole 9 are formed on a flexible insulating base film 1 having an adhesive 3 on its surface and a reinforcing film 4 having an adhesive 6 on its surface. Necessary holes such as are formed in the same size and the same arrangement by punching and punching. At this time,
Further, the reinforcing film 4 is provided with a slit 5 at a bent portion 12 which requires bending at the time of mounting (see FIG. 3).
(A)). The shape of the slit 5 depends only on the precision of the punching punching process of the reinforcing film, and basically there is no restriction on the shape as long as the strength as the reinforcing film can be maintained.

After that, necessary holes such as the perforation hole, the device hole 8 and the outer hole 9 are aligned with each other, and the reinforcing film 4 is attached to the insulating base film 1 with the adhesive 6 (FIG. 3 (b)). Then, a conductive metal foil such as a copper foil is heat-bonded to the surface of the insulating base material film 1 on the opposite side of the back surface to which the reinforcing film 4 is attached by using the adhesive 3. Then, as described above, the wiring pattern 2
Is formed on the insulating substrate film 1 (FIG. 3C).

According to this, since it is not necessary to fill the slit formed in the reinforcing film with the flex resin,
Manufacturing is easy. Further, the slit width is determined by the accuracy of punching and punching processing, but it can be 0.1 mm or more, and there is no restriction as in the past.

In the above-mentioned manufacturing method example, when the TAB film carrier is manufactured, the reinforcing film is attached to the insulating base film before the wiring pattern is formed. The reinforcing film may be attached after the wiring pattern is formed.

[0025]

According to the present invention, there is no restriction on the slit shape formed in the bent portion, the bending characteristics are good, and the bending resistance can be improved more than twice as compared with the conventional flex resin-filled TAB. , Excellent in reliability.

Further, according to the method of the present invention, since it is not necessary to fill the formed slit with the flex resin, the manufacturing is easy.

[Brief description of drawings]

1A and 1B are views showing an embodiment of a TAB film carrier of the present invention, in which FIG. 1A is a perspective view and FIG. 1B is a sectional view taken along line AB.

FIG. 2 is a cross-sectional view showing a usage state of the TAB film carrier of the present embodiment.

FIG. 3 is an explanatory view showing a method for manufacturing a TAB film carrier of the present embodiment.

FIG. 4 is a cross-sectional view of a conventional flex resin-filled TAB film carrier.

[Explanation of symbols]

 1 Insulating Base Film 2 Wiring Pattern 3 Adhesive 4 Reinforcing Film 5 Slit 6 Adhesive 7 Perforation Hole 8 Device Hole 9 Outer Hole 10 Inner Lead 11 Outer Lead 12 Bent Part

Claims (3)

[Claims] 1. A reinforcing film is attached to the back surface of a flexible insulating substrate film having a wiring pattern formed on the surface,
A film carrier for TAB having slits formed at the bending portions that require bending when mounting the reinforcing film. 2. The insulating base material film is composed of a polyimide resin having a high flexibility when bent, and the reinforcing film material is composed of a polyimide resin capable of sufficiently securing mechanical strength. TAB film carrier. 3. A flexible insulating base film and a reinforcing film for reinforcing the insulating base film are formed with necessary holes such as perforation holes, device holes and outer holes in the same size and the same arrangement. Slits are formed in the bending part that requires bending at the time of mounting, and the perforation hole, device hole,
For TAB in which necessary holes such as outer holes are aligned and a reinforcing film is attached to the insulating base film, and a wiring pattern is formed on the surface of the insulating base film opposite to the back side on which the reinforcing film is attached. Film carrier manufacturing method.