JP2001127119A - Flexible tape for forming fine pattern and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film base IC mounted board which can utilize the prior art TAB tape manufacturing line and has an ultrafine pitch of 50μm or less, particularly, a flexible tape which can be bonded with outer leads by bending TAB system after mounting an LCD driven IC. SOLUTION: This bending tape consists of a first film layer (a) and a second film layer (c) with an adhesive layer (b) in between: the second film layer is surfaced with a metal layer (d), and the first film layer (a) and the adhesive layer (b) can easily be released integrally from the rear of the second film layer (c).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible tape used for manufacturing a flexible substrate having a fine pitch for mounting a semiconductor integrated circuit (IC), in particular, a pattern pitch of less than 50 .mu.m, and a method for manufacturing the same.

[0002]

2. Description of the Related Art For a liquid crystal display element (LCD), especially a driving IC for a large LCD such as a notebook PC and a monitor, a TCP (tape carrier package) using a TAB tape as a mounting substrate is preferably used. With the progress of definition, multi-output drive IC, and miniaturization of IC, T
The pattern pitch of the TAB tape used for the CP continues to be finer.

[0003] In response to finer TAB tape patterns, in terms of material, high dimensional stability of the base film, higher functionality of the adhesive (higher adhesion, higher insulation reliability), thinner copper foil and copper foil bonding treatment This has been realized by flattening the surface, etc., and the inner lead (I
L) The pitch is 50 μm, and even finer pitches (about 45 μm) have been realized.

[0004] It is desirable to further refine the TAB tape pattern pitch as an LCD drive IC mounting substrate. However, if the area is less than 50 µm, especially less than 45 µm, there is a limit to the use of the TAB tape system as it is.
That is, in order to form an ultra-fine copper pattern by the subtractive (etching) method, it is an absolute requirement that the thickness of the copper foil be reduced, but the leading end of the inner lead of the TAB tape is a so-called flying lead. And is not supported by the base film. Therefore, when the thickness of the copper foil is reduced in response to the fine pitch, the bending strength of the inner lead is rapidly reduced. Therefore TA
In the process of manufacturing or handling the B tape, the flying leads of multiple outputs are bent, and the yield is poor, and the practical value is greatly reduced industrially.

For this reason, instead of the TAB (flying lead) method, an ultra-fine pattern is formed using a material composed of a base film and an ultra-thin copper foil.
A (COF) method in which a D drive IC is mounted is being studied.

On the other hand, in order to produce a super fine pattern tape by the subtract method, photoresist coating, exposure,
It is most suitable to use the conventional TAB tape production line for both development and etching. However, if the base film is thin, the film is weak and the tape cannot be transported smoothly. There is a problem that it is difficult to apply the method.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a conventional TAB.
Utilizes a tape production line and has an ultra-fine pitch film-based IC mounting substrate of 50 μm or less.
An object of the present invention is to provide a material for a flexible substrate which can be subjected to outer lead bonding by a bent TAB method after mounting a CD drive IC.

[0008]

That is, the present invention provides the following:
And a second film layer (c) via an adhesive layer (b), a metal layer (d) is formed on the surface of the second film layer, and the first film layer ( The present invention provides a flexible tape characterized in that a) and an adhesive layer (b) are integrated and can be easily separated and separated from the back surface of the second film layer (c), and a method for producing the same.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail.

The flexible tape in the present invention is
A tape material for manufacturing a flexible substrate (FPC) for mounting a semiconductor element, which is suitably used especially when forming a super fine pattern in a TAB tape manufacturing line.

In a TAB-type LCD driving IC, a bent TA called a so-called flex TAB (or bentTAB) is used to reduce a frame portion of a liquid crystal display screen.
It is often mounted on a B tape and mounted on an LCD panel (outer lead bonding: OLB). The bent TAB tape is formed by forming a slit hole in a bent portion of the TAB tape and applying a flexing agent to a conductor in the slit portion (this step is referred to as a flex processing step).

On the other hand, in the COF method using a material having an extremely thin copper foil, it is often difficult to form slit holes. On the other hand, if the thickness of the base film is reduced, it is possible to bend even without slit holes. There is also an advantage that the flex processing step becomes unnecessary.

The flexible tape of the present invention is preferably used as a first film layer (a) for use in a COF system.
And a second film layer (c) via an adhesive layer (b),
It is mainly composed of the metal layer (d) formed on the second film layer, and when the adhesive layer and the second film layer are peeled off, the first film layer and the adhesive layer are integrated and easily formed. The feature is that it can be peeled off. Further, the second film layer and the adhesive layer may be integrated, and may be easily separated from the first film layer.

In the present invention, in order to facilitate the formation of a fine pattern, the thickness of the metal layer is preferably 12 μm or less, more preferably 10 μm, 8 μm, and further preferably 6 μm, so that the shape of the pattern is reduced. It is possible to obtain a higher definition pattern pitch without breaking. The material of the metal layer is preferably copper or a copper alloy foil. Means for forming the metal layer (d) on the surface of the second film layer (c) include a method of laminating a copper or copper alloy foil using an adhesive, and applying a polyimide precursor to the copper or copper alloy foil and drying. There are a method and a method of copper plating on the surface of a film such as polyimide. The most preferable method for making the thickness of the metal layer as thin as possible is a method of plating on the film surface.

The thickness of the second film layer of the present invention is preferably reduced to 40 μm or less, more preferably 30 μm or 25 μm, because the LCD drive IC can be easily folded and mounted at the time of outer lead bonding. The effect increases. In addition, the first film layer and the second
Is preferably 60 μm or more, more preferably 75 μm or more, because the film can be easily transported in a pattern forming process such as resist coating, exposure, development and etching. Note that the stiffness of the film, which affects the film transportability, is the elastic modulus and the film thickness of the film, and is particularly strongly dependent on the film thickness.

The first type used for the flexible tape of the present invention
The material of the second film is not particularly limited as long as it satisfies heat resistance, dimensional stability, chemical resistance, electrical insulation, and the like, but typical examples include “Kapton”, “apical”, and “upilex”. And the like.

For the material of the adhesive layer (b), TAB
Usually, a TAB tape adhesive is preferably used to avoid damage due to peeling or chemical penetration during the tape patterning process, but ultimately a conductor bonding function or an insulating function is used. Since other adhesives are not required, other adhesives can be used, and there is no particular limitation. However, in the final step, it is necessary that the first film layer (a) can be easily peeled off alone or integrated with the adhesive layer (b). The thickness of the adhesive is not particularly limited, and is usually appropriately selected in the range of 3 to 30 μm.

In the present invention, the adhesive layer (b), the first
Although it depends on the material of the film layer (a) and the second film layer (c), in order to make the peeling easier and to stabilize the shape of the tape after the peeling, a release treatment is performed on the target peeling interface. Preferably a layer is present. Specifically, an interface between the first film layer (a) and the adhesive layer (b) or an interface between the adhesive layer (b) and the second film layer (c), and any one of them Is fine. The material of the release treatment layer is not particularly limited as long as it has a desired release property, but a silicone release agent is preferably used. Specifically, Toray Dow Corning Co., Ltd. silicone release agent SR
X-244, SRX-345, SRX-357, SRX
-370, SD-7223, SD-7227 and the like can be appropriately selected and used. An actual release layer is formed by dissolving and diluting each release agent, adding a predetermined amount of a corresponding predetermined curing catalyst, and applying and drying heat treatment on the film surface.

In the present invention, the first film layer (a)
, Or the first film layer (a) and the adhesive layer (b) are integrated, but the peel strength for easily separating and removing is 3 N / cm or less, preferably 1 N / cm or less. , More preferably 0.5 N / cm or less. However, if it is 0.1 N / cm or less, it is not preferable because it peels off during the conveyance of the pattern forming step.

The measuring method of the peeling strength is described in JIS-K
6854 (Adhesive peel strength test method)
It shall conform to the T-type peel test.

As for the method for producing the flexible tape of the present invention, it is preferable to first provide an adhesive layer on the first film layer, and then bond the second film layer having the metal layer formed thereon. When a release treatment layer is provided, (1) the surface of the second film layer (c) on which the metal layer (d) is formed, on which the metal layer is not formed, is subjected to release treatment in advance, and an adhesive (2) The surface of the second film layer (c) on which the metal layer (d) is formed, where the metal layer is not formed, is previously bonded to the first film layer (a) provided with the layer (b). Release treatment and adhesive layer (b) on the release treatment surface
Is formed on the first film layer (a).

As a method for laminating each film, a roll lamination method is suitable, but not limited thereto.

The adhesive layer (b), the second film layer (c) and the metal layer (d) of the flexible tape of the present invention in the width direction are formed by forming both ends of the first film layer (a) on both sides of the tape. It is preferable that the sprocket hole exists inside the sprocket hole portion formed at the bottom. The configuration in the width direction of the tape in this case is as shown in FIG. The TAB tape is provided with a sprocket hole (index hole) at the tape edge portion, and is used for film transport in each step or tape feeding and positioning in an exposure step. The flexible tape of the present invention is also subjected to pattern processing (photoresist coating, exposure, development, etching,
(For example, plating), so that the sprocket holes do not form a pattern. That is, there is no need to provide a metal layer in this portion, and there is an advantage that the photoresist does not spread to the sprocket portion at the time of applying the photoresist because the copper foil does not exist in the sprocket hole portion. Furthermore, since the sprocket holes are formed by press punching using a mold, there is an advantage that a single layer is easier to press punch than a multilayer structure. However, in this case, the thickness of the first film layer (a) is desirably 50 μm or more.

After the pattern is formed, the conductor pattern is plated with tin, gold or the like as necessary, and the IC is mounted. IC
Before the mounting or after the mounting of the IC, the first film layer (a) or the first film layer (a), which is a carrier, and the adhesive layer (b) are integrated, peeled, separated and used.

In the flexible tape of the present invention, the thickness of the metal layer (d) is as thin as 12 μm or less, and the sum of the thicknesses of the first film (a) and the second film (b) is 60 μm.
It is thicker than above.
It is easy to form a conductor pattern having an ultra fine pitch of less than 0 μm. Further, since the thickness of the second film serving as the conductor supporting substrate is small, and the first film (a) or the first film and the adhesive layer (c) are integrated and can be easily peeled off in the final step, the liquid crystal As a COF substrate on which a driving IC is mounted, it can be connected to a liquid crystal panel by a bending method.

In addition, the flexible tape of the present invention can be extremely suitably used not only for the above-mentioned applications but also for applications which are easy to bend and require a flexible substrate having an ultra fine pitch.

[0027]

The present invention will be described more specifically with reference to the following examples.

Example 1 An adhesive # 7100 for TAB tape (manufactured by Toray Industries, Inc.) was applied to a polyimide film "UPILEX" 50S (manufactured by Ube Industries, Ltd.) 50S (thickness: 50 μm, width: 508 mm) and dried. An adhesive layer (b) was formed on the surface of the film layer (a). The thickness of the adhesive after drying is 12 μm. The adhesive was dried and then subjected to an aging heat treatment to make the adhesive semi-cured.

In addition, the adhesive-free FP manufactured by Nippon Steel Chemical Co., Ltd.
Copper-clad laminate for C "ESPANEX" SC12-25-0
0WE (polyimide film layer (c) thickness 25 μm,
A copper tape layer (d) having a thickness of 12 μm and a width of 500 mm) was adhered by a roll laminating method, and a thermosetting treatment of an adhesive # 7100 was performed to prepare a flexible tape having a configuration shown in FIG. This is slit to a width of 35 mm so that it can be used in a TAB tape processing line. After forming a sprocket hole, the surface of the copper foil is polished (regulated), photoresist is applied, and a pattern is exposed (pattern pitch 45 μm, L / L
S = 25/20 setting, 384 output TAB for LCD
A pattern was formed by a series of TAB tape processes of (model pattern), development, copper etching, solder resist coating, tin plating.

The sum of the thicknesses of the first film layer (a) and the second film layer (c) was 75 μm, and the transportability in the TAB tape processing line was good.

Since the copper foil used was as thin as 12 μm, no pattern loss occurred and the conductor cross-sectional shape was appropriate.

(A) + (b) // (c) +
(D) The peel strength at the interface was 2.8 N / cm, and there was no difficulty in peeling. Furthermore, since the thickness of the second film layer (c) was as thin as 25 μm, it was also confirmed that bending resistance was low and bending mounting was easy.

Example 2 Two-layer adhesiveless FP manufactured by Toyo Metallizing Co., Ltd. having a copper layer formed on the surface of a polyimide film by plating.
C substrate "Metaroyal" PI-25B-CCS-08 (Polyimide film layer (c) thickness 25 μm, copper layer (d) thickness 8 μm
m, width of 500 mm) on a film surface of a condensation-reactive silicone release agent (SRX24 manufactured by Toray Dow Corning Co., Ltd.
4 / Specified amount of catalyst SRX-224AC, toluene / n-hexane = 3/7 mixed solvent, 0.6% solution) was applied and dried (basis weight 0.1 g / m ² ).

This was laminated to the polyimide film (a) / adhesive (b) laminate used in Example 1 by a roll laminating method, and subjected to a thermosetting treatment of an adhesive # 7100 to obtain a flexible tape having the structure shown in FIG. It was created.

A model sample having a pattern pitch of 35 μm (L / S = 20/15) was prepared in the same manner as in Example 1. Since the copper foil thickness was as thin as 8 μm, good results were obtained without pattern defects.

In addition, the first film layer and the adhesive layer were integrated and easily peeled from the second film layer, and the peel strength was 0.8 N / cm.

The thickness of the second film layer (c) is 25 μm.
It was also confirmed that bending resistance was low and bending mounting was easy because of the small thickness of m.

Example 3 Film carrier tape 3 for TAB tape manufactured by Toray Industries, Inc.
1N0-00JS (base film: "UPILEX" 75S (manufactured by Ube Industries, Ltd.), width 48 mm, adhesive # 7100 (manufactured by Toray Industries, Ltd.), adhesive width 41 mm, adhesive thickness 12 μm) The "Metaroyal" PI-25B-CCS-08, which has been subjected to the release treatment used in Step 2, is slit to a width of 41 mm, bonded together by a roll lamination method, subjected to a thermosetting treatment of an adhesive, and configured as shown in FIG. A flexible tape was created.

Using this, a model sample having a pattern pitch of 35 μm (L / S = 20/15) was prepared in the same manner as in Example 1. Since the copper foil thickness was as thin as 8 μm, good results were obtained without pattern defects.

Further, since the sprocket hole forming portion of this flexible tape is only the first film layer (a), the sprocket hole region was not contaminated with the resist when the photoresist was applied to the copper surface, and was easy to handle. .

First film layer (a) and adhesive layer (b)
Was integrated and easily peeled off from the second film layer (c), and the peel strength was 0.8 N / cm.

Further, the thickness of the second film layer (c) is 2
Since the thickness was as thin as 5 μm, it was also confirmed that bending resistance was low and bending mounting was easy.

Example 4 A TAB tape adhesive # 7100 was applied to a release layer obtained by applying and drying a silicone release agent on the film surface of "Metaroyal" PI-25-CCS-08 used in Example 2. Was applied and dried (application thickness: 8 μm), and the adhesive was semi-cured by aging heat treatment. To this product Toray Dupont Co., Ltd.
Polyimide film "Kapton" 200EN (thickness 5
0 μm) was subjected to a thermosetting treatment of a bonding adhesive by a roll lamination method to prepare a flexible tape having a configuration shown in FIG. Example 1
Pattern pitch 35 μm (L / S = 20)
/ 15) model sample was prepared. 8μ thick copper foil
Since m was thin, good results were obtained without pattern loss.

In addition, the first film layer and the adhesive layer were integrated and easily peeled from the second film layer, and the peel strength was 0.8 N / cm.

Further, the thickness of the second film layer (c) is 2
Since the thickness was as thin as 5 μm, it was also confirmed that bending resistance was low and bending mounting was easy.

Example 5 "Metaroyal" PI-25B-C manufactured by Toyo Metallizing Co., Ltd.
Toray Co., Ltd. T
The AB tape adhesive (b) # 7100 was applied and dried (dry thickness: 12 μm), and further the adhesive was semi-cured by aging heat treatment. A polyimide film "(a) Upilex" 50S (thickness: 50 μm) which was previously subjected to release treatment with the same silicone release agent as used in Example 2 was used.
m) were laminated by a roll laminating method, and a thermosetting treatment of an adhesive was performed to prepare a flexible tape having a configuration shown in FIG. This was slit to a width of 35 mm, and a pattern pitch of 35 μm (L / S = 20 /
15) A model sample was prepared. Copper foil thickness is 8μm
As a result, good results were obtained without pattern defects.

In addition, the first film layer and the adhesive layer were integrated and could be easily peeled off from the second film layer, and the peel strength was 0.8 N / cm.

Further, the thickness of the second film layer (c) is 2
Since the thickness was as thin as 5 μm, it was also confirmed that bending resistance was low and bending mounting was easy.

[0049]

By using the flexible tape of the present invention, an ultra-fine pitch flexible substrate of less than 50 μm can be produced with good yield using a TAB tape processing line.
Can be folded and mounted on liquid crystal panels.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the basic structure of a flexible tape according to the present invention.

FIG. 2 is a cross-sectional view in the width direction of the flexible tape according to claim 9 of the present invention.

[Explanation of symbols]

 Reference Signs List 1 first film layer (a) 2 adhesive layer (b) 3 second film layer (c) 4 metal layer (d) 5 tape end sprocket hole forming portion

Claims (12)

[Claims] 1. A first film layer (a) comprising a first film layer (a) and a second film layer (c) via an adhesive layer (b).
A metal layer (d) is formed on the surface of the film layer, and the first film layer (a) and the adhesive layer (b) are integrated and easily peeled off from the back surface of the second film layer (c) and separated. Flexible tape characterized by being able to. 2. The flexible tape according to claim 1, wherein the thickness of the metal layer (d) formed on the surface of the second film layer is 12 μm or less. 3. The flexible tape according to claim 1, wherein the second film layer (c) and the adhesive layer (b) are integrated and easily peeled off from the first film layer (a). Flexible tape characterized by being separable. 4. A first film layer (a) and an adhesive layer (b)
4. The flexible tape according to claim 1, wherein a release treatment layer is present at an interface of the adhesive layer or at an interface between the adhesive layer (b) and the second film layer (c). 5. The flexible tape according to claim 4, wherein the release treatment layer contains a silicone compound. 6. The thickness of the second film layer (c) is 40 μm.
Below, and the sum of the first and second film thicknesses is 60 μm
The flexible tape according to claim 1, wherein: 7. A first film layer (a) and an adhesive layer (b)
2. The flexible tape according to claim 1, wherein the peel strength from the back surface of the second film layer (c) is less than 3 N / cm. 8. The widths of the adhesive layer (b), the second film layer (c), and the metal layer (d) are inside the sprocket holes formed at both ends of the tape of the first film layer (a). The flexible tape according to claim 1, wherein 9. An adhesive layer (b) is provided on the surface of the first film layer (a) in advance, and the second film layer (c) on which the metal layer (d) is formed is laminated. The method for producing a flexible tape according to claim 1. 10. A second film layer (c) on which a metal layer (d) is formed, a surface of the second film layer (c) on which the metal layer is not formed is subjected to a mold release treatment in advance, and an adhesive layer (b) is provided. 2. The method for producing a flexible tape according to claim 1, wherein the flexible tape is laminated with the first film layer (a). 11. A surface of the second film layer (c) on which the metal layer (d) is formed, on which the metal layer is not formed, is subjected to a release treatment in advance, and an adhesive layer (b) is formed on the release treated surface. 2. The method for producing a flexible tape according to claim 1, wherein the formed film is bonded to the first film layer (a). 12. A second film layer (c) on which a metal layer (d) is formed, wherein an adhesive layer (b) is formed on a surface on which the metal layer is not formed, is subjected to a mold release treatment in advance. 2. A laminate according to claim 1, wherein said laminate is laminated with said first film layer (a).
A method for producing the flexible tape according to the above.