JPH0766933B2 - TAB tape manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a TAB (Tape Au).
The present invention relates to a method for manufacturing a tomated bonding tape, and particularly to a method for manufacturing a TAB tape that is preferably used for manufacturing a TAB having a fine pitch pattern.

[0002]

2. Description of the Related Art A TAB tape used for manufacturing a TAB is obtained by adhering a copper foil, which is a conductive layer, to one side or both sides of a base film (resin film) such as a polyimide, and is laminated with three layers or five layers. It has a structure.
Adhesion between the base film and the copper foil is usually performed via an adhesive.

An electrolytic copper foil is generally used as such a copper foil. Electrolytic copper foil is obtained by peeling the copper foil deposited on the drum. The surface peeled from the drum (glossy surface) is relatively smooth, but the opposite surface, the deposition surface (rough surface), is uneven. Have. The rough surface of the TAB tape is adhered to the base film. In order to improve the peel strength with the base film, this rough surface has a grain size of 0.
Copper fine particles of 5 to 2.0 μm are attached. Therefore, copper fine particles are further attached on the irregularities, and the surface roughness (Rz: ten-point average roughness) increases. Therefore, when this is pattern-etched, etching having a sharp line cannot be performed, and copper particles adhere and remain at the root of the etching pattern of the base film.

Therefore, a general electrolytic copper foil is not suitable for the production of TAB having a fine pitch, and an electrolytic copper foil having high hardness and relatively small surface irregularities is used for this application. Such an electrolytic copper foil can be obtained by means such as adjusting the liquid composition. Since this copper foil has relatively small irregularities and a surface roughness (Rz) of 2.0 to 3.0 μm, 80 μm
It can be used to form a pattern of about m pitch, but when the pattern pitch becomes finer, such as 50 to 60 μm, the copper electrodeposited particles remaining at the base of the etching pattern are left between the conductors. This may cause a short circuit if the insulation resistance is reduced or severe.

The rolled copper foil can be used for this purpose by attaching a beard-like, dendritic or bump-like electrodeposit. However, in order to make a fine pitch pattern of about 50 to 60 μm, the thickness of the copper foil should be 18 to 25 μm.
It must be made as thin as possible, and preparing a copper foil of this thickness by rolling requires many steps, resulting in an increase in cost. Further, when the thickness of the copper foil is reduced by rolling, there is a problem that minute scratches caused by inclusion of dust or the like in the coolant during rolling adversely affect the properties of the copper foil.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the problems of the prior art, does not cause a decrease in peel strength, and is excellent in economic efficiency, and copper is used as the base of the etching pattern of the base film. TAB that has a fine fine pitch pattern without particles adhering and remaining
It is an object of the present invention to provide a method for producing a TAB tape that enables the production of the above.

[0007]

The above object of the present invention is achieved by forming a bond between a glossy surface of an electrolytic copper foil and a base film and smoothing a rough surface of the electrolytic copper foil.

That is, according to the method for producing a TAB tape of the present invention, a copper electrodeposition is formed at a height of 0.2 to 1.0 μm on a glossy surface of an electrolytic copper foil, and copper plating is further adhered on this. Thereafter, the base film is bonded to the glossy surface, and then the surface roughness (Rz) of the rough surface of the electrolytic copper foil is smoothed to less than 3.0 μm.

The manufacturing method of the present invention will be further described below. 1 (a) to 1 (c) are manufacturing process diagrams of a method for manufacturing a TAB tape of the present invention.

As shown in FIG. 1A, electrolytic copper foil 1
The copper electrodeposited material 2 is formed on the glossy surface 1a of the above in a height of 0.2 to 1.0 μm. Examples of the copper electrodeposit 2 include a beard-shaped, dendritic or bump-shaped copper electrodeposit. In order to form such a copper electrodeposit 2, it is formed by electroplating at normal temperature under high current density. The plating bath used at this time is, for example, CuSO ₄ .5H ₂ O 32 g / l, H ₂ SO ₄ 1
A copper sulfate plating bath consisting of 00 g / l is preferably used. If the height of the electrodeposited copper is less than 0.2 μm, the adhesion to the base film is poor, and if it exceeds 1.0 μm, copper particles adhere to and remain at the base of the etching pattern of the base film when forming a fine pattern by etching. It becomes a state. Further, copper plating (not shown) is applied on the copper electrodeposit 2 at a low current density to improve the adhesion of the copper electrodeposit to the copper foil. If desired, a suitable rust preventive treatment may be applied.

Next, the copper foil 1 is pre-slit to an appropriate width, and then a copper electrodeposit 2 is formed as shown in FIG. 1 (b), and the copper foil is plated with a shiny surface 1a. 1 and the base film 3 are bonded. The base film 3 is not particularly limited, but a polyimide film is generally used. This bonding is usually performed via the adhesive 4, and an epoxy thermosetting adhesive or the like is used.

In this way, the copper foil 1 and the base film 3 are
A TAB tape (copper-clad laminate) in which and are laminated is obtained. The exposed surface of the copper foil 1 is a rough surface 1b, and the surface roughness (Rz) has irregularities of about 3 to 12 μm. , It is not possible to apply a resist on this. Therefore, in FIG.
As shown in (c), it is smoothed by chemical polishing such as etching. Examples of the etching solution used for this chemical polishing include cupric chloride, hydrochloric acid and hydrogen peroxide solution. It is necessary to make the surface roughness (Rz) less than 3 μm by this smoothing, and if the surface roughness is higher than this, it becomes difficult to apply the resist.
The TAB tape is obtained through the above steps.

In order to produce a TAB having a fine pattern from this TAB tape, a resist is applied to the exposed surface (rough surface) of a smoothed copper foil, and exposure, development and etching are usually conducted by a photolithographic method. A fine pitch pattern having a pitch of about 50 μm is obtained by the above method.

In the TAB thus obtained, the lines are sharply etched without copper particles adhering to and remaining at the root of the etching pattern of the base film.

[0015]

By using the TAB tape obtained by the present invention, a TAB having a fine pitch pattern that is sharply etched can be obtained. Further, since the line width can be designed to be thick even with the same pitch, the strength of the inner leads is increased accordingly, and the bending and bending of the leads during the process can be reduced. Moreover, it is possible to use various copper foils, for example, a fine pitch pattern cannot be formed by a usual method due to the large unevenness of the matte surface, but the copper foil has large elongation, good flexibility, and excellent folding endurance. Can also be used. Furthermore, since the thickness can be adjusted by etching, the degree of freedom in circuit design such as resistance and strength can be increased.

[0016]

EXAMPLES The present invention will be specifically described below based on Examples and the like.

Example 1 A polyimide resin tape (Upilex S, Ube Industries, Ltd.) having a thickness of 75 μm and a width of 35 mm and an epoxy thermosetting adhesive (# 5700, manufactured by Toray Industries, Inc.) applied to a thickness of 20 μm was punched. After punching out the device holes, etc., laminating at 150 ° C so that the glossy side of the electrolytic copper foil with the acicular copper electrodeposit formed on the glossy side is in contact with the polyimide resin, and then at a maximum of 160 ° C for about 24 hours. It was applied and cured. The width of the copper foil was about 26.5 mm. In addition, the formation of the copper electrodeposit on the glossy surface of the electrolytic copper foil is H ₂ SO ₄
Using a plating solution consisting of 100 g / l and CuSO ₄ .5H ₂ O 32 g / l, under the condition of current density 50 A / dm ² ,
Electroplating for 10 minutes at room temperature, 0.5-1.0μ
It was formed to have a height of m.

Further, a plating solution of 100 g / l of H ₂ SO ₄ and 150 g / l of CuSO ₄ .5H ₂ O was used for electroplating at room temperature for 60 seconds at a current density of 2 A / dm ² . A 0.5 μm plated layer was formed.

Next, the polyimide resin side was coated with a positive photocurable resist ink in order to protect the copper on the device hole and the back surface of the slit portion. The roughness (Rz) of the rough surface of this copper foil was 6 μm. The thickness of the copper foil was 35 μm. Next, by using an etching machine, an etching solution having a composition of cupric chloride of about 120 g / l and hydrochloric acid of 100 g / l is sprayed on the roughened surface at a spray pressure of 0.8 Kg / cm ² for etching for about 1 minute. Was reduced to about 18 μm. The roughness (Rz) of the rough surface of the TAB copper foil thus obtained is 0.5 to 1.
It was 0 μm.

Next, using this TAB tape, a positive type liquid resist was coated on the rough surface to a thickness of about 4 μm and further baked. After that, a mask pattern (50 μm pitch) was baked by ultraviolet rays. After developing with alkali, the pattern was etched again using the etching machine. TAB with fine pitch pattern after finishing the surface by tin plating after etching
Got

A schematic view of the inner lead portion of the TAB thus obtained is shown in FIG. In the figure, 3 is a base film and 5 is a fine pitch pattern. The line width of this inner lead is 15 μm, and the gap is 35 μm.
m, and no copper particles adhered to and remained at the root of the etching pattern on the base film (polyimide resin). The peel strength after etching is 11 to 1
The width was 3 g / 100 μm and the peel strength after tin plating was 7 to 8 g / 100 μm.

Comparative Example 1 Similar to Example 1, 35 m of a 75 μm thick polyimide resin was used.
After the epoxy tape thermosetting adhesive is applied to the width tape to a thickness of 20 μm, the device hole is punched out by punching, and then the electrolytic copper foil with the copper electrodeposit on the rough surface is in contact with the polyimide resin. Thus, it was laminated at 150 ° C. and then cured at a maximum of 160 ° C. for about 24 hours. The width of the copper foil was about 26.5 mm. The conditions for forming the copper electrodeposit on the rough surface of the electrolytic copper foil were the same as in Example 1, and the copper electrodeposit was formed to have a height of 0.5 to 1.0 μm. Further, in the same manner as in Example 1, the copper plating film 0.5
μm formed.

Next, the polyimide resin side was coated with a positive photocurable resist ink in order to protect the copper on the device hole and the back surface of the slit portion. The roughness (Rz) of the rough surface of this copper foil was 6 μm, and the roughness (Rz) of the glossy surface was 0.4 to 0.6 μm. The thickness of the copper foil was 35 μm. Next, the glossy side was etched by an etching machine in the same manner as in Example 1 to have a thickness of about 18 μm. Thus, a laminated tape for TAB was obtained.

Next, as in Example 1, TAB having a fine pitch pattern was manufactured. The reference numerals are the same as in FIG. A schematic view of the inner lead portion of the TAB thus obtained is shown in FIG. The line width of this inner lead was 25 μm and the gap was 35 μm, and copper particles adhered and remained on the surface of the base film (polyimide resin). The peel strength after etching is 11 to 12 g.
/ 100μm width, peel strength after tin plating is 1
The width was 0 to 11 g / 100 μm.

[0025]

As described above, according to the present invention, a TAB tape which does not cause a decrease in peel strength, is excellent in economical efficiency, and is capable of producing a TAB having a fine fine pitch pattern can be obtained.

[Brief description of drawings]

FIG. 1 is a process diagram of a method for manufacturing a TAB tape of the present invention.

FIG. 2 is a schematic diagram of a fine pitch pattern of an inner lead portion obtained in Example 1.

FIG. 3 is a schematic diagram of a fine pitch pattern of an inner lead portion obtained in Comparative Example 1.

[Explanation of symbols]

1 copper foil, 1a glossy surface, 1b rough surface, 2 copper electrodeposit, 3 base film, 4 adhesive.

Claims (1)

[Claims] 1. A glossy surface of an electrolytic copper foil is 0.2 to 1.0 μm.
After forming a copper electrodeposit on the surface of the copper foil and further depositing copper plating thereon, the base film and the glossy surface are adhered to each other, and then the surface roughness of the rough surface of the electrolytic copper foil is (Rz) 3 0.0 μm
A method for producing a TAB tape, wherein the TAB tape is smoothed to a lower level.