JP2884265B2 - Method for manufacturing two-layer TAB tape - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a two-layer TAB tape, and more particularly, to a method in which a liquid thermosetting resin is applied to a metal foil only as necessary as a support and cured to form a conductive pattern. The present invention relates to a method for manufacturing a two-layer TAB tape which is inexpensive and simple by being formed, and which is excellent in various properties such as bendability, dimensional stability and heat resistance.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 1 and 2, a windowed printed wiring board or TAB tape has a conductor pattern exposed without an insulating substrate portion for supporting the conductor wiring pattern from below. Are partially formed, and these are generally manufactured by a photo-etching method or the like.

[0003] As a method of manufacturing such a TAB tape, as shown in FIG. 3, a metal foil (conductive metal layer) 1 is formed through an adhesive layer 3 made of glue or the like by punching a hole at a desired position. Press bonding to the substrate 2 (FIG. 3A), and then exposing, developing, and etching the metal foil 1 by a photo-etching method to obtain a conductive pattern 4 (FIG. 3B), Printing is performed, and plating of gold or tin is partially performed to form a wiring pattern.

Further, there is a method in which a wiring pattern is formed by photoetching a metal foil after a part of an insulating substrate is chemically or mechanically removed using a two-layer substrate in which no adhesive is present. . This method uses an insulating substrate 2 made of polyimide, as shown in FIG.
After a metal such as copper is sputtered on one side of the above, a metal foil 1 is formed by further thickly plating a metal such as copper thereon, and the other side is similarly sputtered, and a masking of copper or the like is performed by thick plating. A layer 5 is provided (FIG. 4A); then, a portion of the masking agent 5 is etched to expose a portion to be a device hole of the insulating substrate (polyimide) 2 (FIG. 4B). Further, device holes are opened in the insulating substrate 2 by polyimide etching (FIG. 4C); then, the metal foil 1 is exposed, developed and etched by a photo-etching method to obtain a conductor pattern 4 (FIG. 4).
(D)); After further removing the masking layer 5 by etching (FIG. 4 (e)), a solder resist printing is then performed.
Further, a wiring pattern is formed by partially plating gold or tin.

However, in the case of a TAB tape using an adhesive, there is a problem that a mold is required, which requires a long time for manufacturing and is costly. In some cases, the adhesive softens during thermocompression bonding with the liquid crystal panel substrate, causing the conductor to move. In addition, the conductor expands and contracts in a heating step, a washing step, and a drying step, and it is difficult to control the dimensions. Further, the bending property is disadvantageous by the thickness of the adhesive. For this reason, when trying to improve the bendability using a thin film, there is a problem in handling in the continuous processing, wrinkles and cuts are generated in the metal foil, and it becomes difficult to apply the adhesive, particularly This tendency is remarkable in a base film having a thickness of 1 mil (25 μm) or less. Moreover, the TAB tape is widely used for liquid crystal displays. In this case, the TAB tape is bent and used. However, this bending causes cracks. It is necessary to manufacture such a mold, which leads to an increase in cost.

On the other hand, when a two-layer TAB tape without an adhesive is used, a part of the insulating substrate must be chemically etched in order to form a part that is not supported by the insulating substrate, and a masking layer for that purpose is required. In addition, there is a problem that the cost is high due to the fact that an etching agent having a high reactivity is required, and it is not preferable from the viewpoint of environmental hygiene. Further, there is a problem that the shape after the etching is not appropriate and an error occurs. There is also a method of mechanically removing a part of the insulating substrate using an excimer laser or the like, but in this case, there is a problem that the cost becomes extremely high. In addition, in the case of a copper directly attached original plate by the sputtering method,
Copper is generally used as the pattern material, and since electrodeposited copper by electroplating is used, there is no flexibility in controlling the tensile strength, hardness, elongation, and the like and in selecting the material. For example, phosphor bronze, stainless steel, and other copper alloys for lead frames cannot be used.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object thereof is to achieve high density,
Provided is an inexpensive and simple method for manufacturing a two-layer TAB tape which has a fine wiring pattern, has excellent electrical and mechanical properties, does not have an adhesive layer, has no disconnection or short circuit of the wiring pattern. In particular, an object of the present invention is to provide a two-layer TAB tape in which there is no insulating substrate portion for supporting the conductor pattern from below, and a part of the conductor pattern is exposed.

[0008]

The inventor of the present invention has conducted various tests and studies on the manufacturing process of a two-layer TAB tape, and has completed the method of manufacturing a two-layer TAB tape of the present invention.

That is, according to the present invention, a liquid thermosetting resin is applied to the back surface of a metal foil in a predetermined shape, cured by heating, and then the front and back surfaces of the metal foil are coated with a resist. , Developing, and then etching to obtain a conductive pattern.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 5 is a process chart showing the manufacturing method of the present invention. In FIG. 5, reference numeral 1 denotes a metal foil (conductor pattern layer);
Reference numeral 4 denotes a conductor pattern, 6 denotes a liquid thermosetting resin (support layer), 7 denotes a support, 8 denotes a photoresist (dry film), and 9 denotes a solder resist.

As shown in FIG. 1A, in the present invention, a liquid thermosetting resin is applied to the back surface of the metal foil 1 in a predetermined shape. The conductive pattern 4 is formed on the metal foil 1 by a photo-etching method, and it is necessary that the metal foil 1 has at least conductivity. Such a metal foil 1 is appropriately selected, and specific examples thereof include copper, a copper alloy such as phosphor bronze, and stainless steel. On the other hand, the liquid thermosetting resin 6 is applied to a desired portion by screen printing or the like, and is heated and cured to be used as the support 7. The support 7 mechanically supports the metal foil 1 or the conductor pattern 4 during manufacture, and has at least mechanical strength. Examples of the liquid thermosetting resin 6 used as the support 7 include liquid polyimide, epoxy resin, and the like having an appropriate viscosity. A material that is not etched by a photoetching solution for forming a circuit is selected. There is a need.

Next, as shown in FIG. 1B, the front and back surfaces of the metal foil 1 are coated with a resist 8, and a desired conductor pattern 4 is formed on the metal foil 1 by a photo-etching method. This photo etching method is based on a usual technique. For example, a photoresist 8 is applied to the surface of the metal foil 1, a mask (photomask) or the like on which a desired pattern is drawn is placed thereon, and ultraviolet light or the like is irradiated to selectively remove unexposed resist. The metal foil can be etched using the remaining resist as a mask.

In this way, as shown in FIG. 1C, a conductor pattern 4 partially having the support 7 is obtained. Further, in FIG. 3C, the portion of the conductor pattern 4 that is not supported by the support 7 at the window (outer lead window, device hole, etc.) of the support 7 is exposed.

Further, as shown in FIG. 1D, if necessary, a solder resist 9 is applied by printing, and plating of gold or tin is performed partially to form a wiring pattern.

FIG. 6 shows an example of the two-layer TAB tape thus obtained. FIG. 3A shows the pattern surface (× 2).
In this example, no solder resist is applied, and the entire surface is gold-plated. FIG. 2B shows the back surface of the pattern (× 2).

The two-layer TA obtained according to the present invention as described above.
The B tape is subjected to various treatments as necessary, and is provided for the purpose.

[0018]

The operation of the method for producing a two-layer TAB tape according to the present invention is as follows.

(1) Since a liquid thermosetting resin is applied to the metal foil itself to form a windowed portion and a supporting insulating portion, it can be easily performed without punching or polyimide etching. A window can be obtained.

(2) Since no adhesive is used, the obtained TAB tape has excellent flexibility (flexibility), and since it uses a liquid thermosetting resin, it has high heat resistance and good dimensional accuracy.

(3) Liquid thermosetting resin can be thinly applied to the metal foil, and handling is easy if a strong material is used as the metal foil.

(4) The metal foil has selectivity, and characteristics such as tensile strength and hardness can be controlled freely.

(5) Since there is no need to make a mold and only a screen printing mask needs to be made, the manufacturing time can be reduced and the cost can be reduced.

[0024]

According to the present invention, a high-density, fine wiring pattern, excellent electrical and mechanical properties, no adhesive layer, no disconnection or short circuit of the wiring pattern are obtained.
A layer TAB tape can be obtained at low cost and easily.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments.

Example 1 Phosphor bronze foil (width 15 cm, height 15 cm, thickness 40 μm)
Using an ammonium persulfate solution (60 ° C., 20
0 g / l) for 8 minutes to dissolve and roughen the surface.
The thickness was reduced to 30 μm, and four holes for positioning were drilled with a drill.

A liquid thermosetting resin (polyimide varnish, FS-100, manufactured by Ube Industries) was applied to a predetermined portion on the back surface of the phosphor bronze foil by screen printing to a thickness of 9 μm. The screen mask used here was a 200 mesh plate made of Tetron, and the thickness of the emulsion was 20 μm. Screen printing was performed at about 30 cm / sec using a silicone rubber squeegee.

Next, the polyimide was heated and cured in the air at 200 ° C. for 30 minutes to obtain a support. Further, pickling (5%
Sulfuric acid) and after drying, a 25 μm thick dry film (photoresist) was applied to both sides of a phosphor bronze foil with a support at 100 ° C.
Was laminated.

Thereafter, the film was placed in an exposure machine, a pattern mask was placed thereon, and the inside of the chamber was evacuated to irradiate ultraviolet rays at 30 mJ / cm ² to expose both sides. Inner lead pitch is 100μ
m, a line width of 50 μm, and a pattern having 56 pins in four directions were used. Development was carried out with 1% sodium carbonate for 50 seconds (30 ° C.), followed by etching with a cupric chloride solution. The etching was performed at 40 ° C. for 125 seconds.

After peeling off the dry film, a solder resist ink was applied to a thickness of about 10 μm by screen printing, heated at 110 ° C. for 60 minutes, and electroless tin plated to a thickness of 0.1 μm.
A two-layer TAB tape was prepared by depositing to a thickness of 5 μm.

As a result, a desired two-layer TAB tape was obtained. In this two-layer TAB tape, the conductor pattern protruded to the window portion of the substrate and was exposed, but no failure such as breakage, deformation, or contact of the pattern occurred.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a conventionally used windowed printed wiring board.

FIG. 2 is a perspective view showing an example of a conventionally used TAB tape.

FIG. 3 is a process chart showing an example of a conventional method for manufacturing a two-layer TAB tape.

FIG. 4 is a process chart showing another example of a conventional method for manufacturing a two-layer TAB tape.

FIG. 5 is a process chart showing an example of a method for producing a two-layer TAB tape of the present invention.

FIG. 6 is a plan view and a bottom view showing an example of a two-layer TAB tape obtained according to the present invention.

[Description of Signs] 1 Metal foil 2 Insulating substrate 3 Adhesive layer 4 Conductor pattern 5 Masking layer 6 Liquid thermosetting resin 7 Support 8 Photo resist 9 Solder resist

Claims (1)

(57) [Claims] 1. A liquid thermosetting resin is applied on the back surface of a metal foil in a predetermined shape, cured by heating, and then the front and back surfaces of the metal foil are coated with a resist, and the front and back surfaces are exposed and developed. Thereafter, a conductive pattern is obtained by etching, thereby producing a two-layer TAB tape.