JP3252183B2 - Flexible wiring board and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a flexible wiring board and a method for manufacturing the same.

[0002]

2. Description of the Related Art When manufacturing a carrier tape (flexible wiring board) used in TCP (Tape Carrier Package) or the like, as one example, sprocket holes are formed on both sides in the width direction of a base film made of polyimide.
Next, a copper foil is adhered to the wiring forming area at the center in the width direction of one surface of the base film via an adhesive, then a photoresist is applied to the surface of the copper foil, and then exposed and developed to perform photo-forming. A wiring is formed by forming a resist pattern and then etching the copper foil using the photoresist pattern as a mask, and then peeling off the photoresist pattern. In this case, the length of the base film is as long as several tens to hundreds of meters, and the manufacturing process after the formation of the sprocket holes is performed by roll-to-roll by pin roller conveyance.

As a base film made of polyimide, a relatively thick film having a thickness of about 75 to 125 μm is generally used. Such a base film is relatively thick, so that the strength of the sprocket hole portion can be made sufficient, so that the pin of the pin roller can be satisfactorily hooked on the sprocket hole, and the transfer by the pin roller can be performed smoothly. The sprocket hole can be prevented from being deformed.

[0004]

By the way, recently,
As a polyimide base film, the thickness is 25
It has been considered to use a relatively thin one of about μm. However, such a base film is relatively thin, so that the strength of the sprocket hole portion cannot be sufficient, and consequently the pin of the pin roller does not catch on the sprocket hole, and the pin roller cannot be conveyed. In addition, even if the pin of the pin roller is caught on the sprocket hole, the sprocket hole is deformed, which adversely affects the alignment accuracy in a later process. SUMMARY OF THE INVENTION It is an object of the present invention to smoothly carry a pin roller even when a base film has a relatively small thickness, and to prevent sprocket holes from being deformed.

[0005]

According to a first aspect of the present invention, there is provided a flexible wiring board having a base film having a thickness which is so thin that the strength of a sprocket hole portion by itself cannot be as expected. Wiring formed at the center in the width direction of one surface and another surface of the base film
When the reinforcing film is provided as a whole, a dummy wiring is formed on one surface of the base film around the sprocket hole. The method of manufacturing a flexible wiring board according to the invention according to claim 3, wherein the conductive layer is formed on one surface of the base film having such a thickness that the strength of the sprocket hole portion by itself cannot be as expected. And a reinforcing film is provided on the other surface of the base film, and sprocket holes are formed on both sides in the width direction of the base film, the conductive layer and the reinforcing film, and a center in the width direction of one surface of the base film is provided. A wiring is formed by the conductive layer in the portion, a dummy wiring is formed by the conductive layer on one surface of the base film around the sprocket hole, and then the reinforcing film is peeled off. . According to the present invention, the dummy wiring is formed on one surface of the base film around the sprocket hole. Therefore, even if the thickness of the base film is relatively thin, the substantial strength of the sprocket hole portion is required. As a result, the transfer by the pin rollers can be performed smoothly, and the sprocket holes can be prevented from being deformed.

[0006]

1 to 8 show the steps of manufacturing a carrier tape (flexible wiring board) according to an embodiment of the present invention. Therefore, the structure of the carrier tape (flexible wiring board) in this embodiment will be described together with the manufacturing method thereof with reference to these drawings in order.

First, as shown in FIG. 1, a copper foil (conductive layer) 3 having a thickness of about 8 μm is attached to the upper surface of a base film 1 made of polyimide having a thickness of about 25 μm via an adhesive 2. In this case, the base film 1 and the copper foil 3 are long and have a width of 35 mm. In this embodiment, a three-layer structure of the base film 1, the adhesive 2, and the copper foil 3 is used, but a two-layer structure of the base film 1 and a conductive layer such as the copper foil 3 may be used.

Next, as shown in FIG. 2, a reinforcing film 5 made of PET (polyethylene terephthalate) having a thickness of about 50 μm is attached to the lower surface of the base film 1 via an adhesive 4. The reinforcing film 5 also has a long width of 35 mm. The reinforcing film 5 is for ensuring conveyance during the manufacturing process, and has a thickness of 50 μm.
It may be the above. For example, the thickness of the reinforcing film 5 may be about 100 μm or about 125 μm,
The transport during the manufacturing process can be further ensured as the thickness increases.

Next, as shown in FIG. 3, a base film 1, an adhesive 2,
Sprocket holes 6 are formed on both sides in the width direction of the copper foil 3, the adhesive 4, and the reinforcing film 5.

Next, as shown in FIG. 4, the pin 8 of the pin roller 7 is engaged with the sprocket hole 6, and in this state, the pin roller 7 rotates in a predetermined direction at a predetermined speed, thereby obtaining the base film 1 and the like. Is transported in a predetermined direction at a predetermined speed. In this case, the reinforcing film 5 is on the pin roller 7 side. And in this conveyance, the copper foil 3
A dry film resist 9 on the upper surface of the substrate. In this state, the upper surface side of the sprocket hole 6 is covered with the dry film resist 9. Note that the dry film resist 9 is also made of a long material having a width of 35 mm.

Here, the thickness of the base film 1 is 25 μm.
Even though it is relatively thin, about m, the reinforcing film 5 having a thickness of about 50 μm or more is attached to the lower surface of the base film 1, so that the substantial thickness of the entire film becomes relatively thick. As a result, the pin 8 of the pin roller 7 is prevented from contacting the dry film resist 9 so that the pin roller 7
Can be smoothly carried out, and the sprocket hole 6 can be prevented from being deformed.

Next, as shown in FIG. 5, by performing predetermined exposure and development, a predetermined resist pattern 9a is formed in a wiring forming region at the center in the width direction on the upper surface of the copper foil 3, and A strip-shaped resist pattern 9b is formed on both sides in the width direction of the upper surface of No.3. Therefore, in this state, the upper surface side of the sprocket hole 6 is covered with the belt-shaped resist pattern 9b.

Next, as shown in FIG. 6, by etching the copper foil 3 using the resist patterns 9a and 9b as a mask, a predetermined wiring 3a is formed in the wiring forming area at the center in the width direction on the upper surface of the base film 1. And a strip-shaped dummy wiring 3b on both sides in the width direction of the upper surface of the base film 1.
To form In this case, a part of the sprocket hole 6 is directly formed in the dummy wiring 3b.

Next, when the resist patterns 9a and 9b are peeled off, the result is as shown in FIG. Next, the reinforcing film 5
Is peeled off, a carrier tape shown in FIG. 8 is obtained.
FIG. 9 shows a plan view of an example of the carrier tape in this state. In the carrier tape thus obtained, the strip-shaped dummy wirings 3b are formed on both sides in the width direction on the base film 1 even if the thickness of the base film 1 is relatively thin, about 25 μm. Since the dummy wirings 3b are formed on the base film 1 around the sprocket holes 6, the substantial strength of the portions of the sprocket holes 6 can be as expected. Therefore, even after the steps shown in FIGS. 8 and 9, the conveyance by the pin rollers 7 can be performed smoothly, and the sprocket holes 6 can be prevented from being deformed, which adversely affects the alignment accuracy in the subsequent steps. Can have no effect.

The adhesive 4 on the lower surface of the base film 1 may be removed. In this case, the lower surface of the base film 1 is not sticky and does not adhere with dust, so that the workability can be improved.

In the above embodiment, the case where the base film 1 has a width of 35 mm has been described. However, the present invention is not limited to this, and a film having a width of 70 mm or more may be used. As an example, FIG. 10 shows a manufacturing process corresponding to the case shown in FIG. 7 when a base film having a width of 70 mm is used. In this case, sprocket holes 6 are formed on both sides in the width direction of the base film 1, the adhesive 2, the copper foil 3, the adhesive 4, and the reinforcing film 5 having a width of 70 mm, and two sprocket holes 6 are formed in the center in the same width direction. 6 are formed. The strip-shaped dummy wiring 3a that covers the upper surface of the two sprocket holes 6 at the center in the width direction is divided into two at the center in the width direction.

When the base film 1, the adhesive 2, the copper foil 3, the adhesive 4, and the reinforcing film 5 are cut between the dummy wirings 3a covering the upper surfaces of the two sprocket holes 6 at the center in the width direction, As shown in FIG.
Two carrier tapes are obtained. Next, when the reinforcing film 5 is peeled off from each carrier tape, two carrier tapes having a width of 35 mm are obtained as shown in FIG.
Also in this case, the adhesive 4 on the lower surface side of the base film 1 may be removed.

[0018]

As described above, according to the present invention, since the dummy wiring is formed on one surface of the base film around the sprocket hole, even if the thickness of the base film is relatively small, The substantial strength of the sprocket hole portion can be as expected, so that the conveyance by the pin roller can be performed smoothly, and the sprocket hole can be prevented from being deformed, and as a result, in the subsequent process The alignment accuracy can be prevented from being adversely affected.

[Brief description of the drawings]

FIG. 1 shows a carrier tape according to an embodiment of the present invention.
Sectional drawing which shows the initial manufacturing process of (flexible wiring board).

FIG. 2 is a sectional view showing a manufacturing step following FIG. 1;

FIG. 3 is a sectional view showing a manufacturing step following FIG. 2;

FIG. 4 is a sectional view showing a manufacturing step following FIG. 3;

FIG. 5 is a sectional view showing a manufacturing step following FIG. 4;

FIG. 6 is a sectional view showing a manufacturing step following FIG. 5;

FIG. 7 is a sectional view showing a manufacturing step following FIG. 6;

FIG. 8 is a sectional view showing a manufacturing step following FIG. 7;

FIG. 9 is a plan view of the state shown in FIG. 8;

FIG. 10 is a sectional view showing a manufacturing process corresponding to the case shown in FIG. 7 of the carrier tape (flexible wiring board) according to another embodiment of the present invention.

FIG. 11 is a sectional view showing a manufacturing step following FIG. 10;

FIG. 12 is a sectional view showing a manufacturing step following FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base film 2 Adhesive 3 Copper foil 3a Wiring 3b Dummy wiring 4 Adhesive 5 Reinforcement film 6 Sprocket hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H05K 1/02

Claims (4)

(57) [Claims] 1. A base film having a thickness such that the strength of a sprocket hole portion by itself cannot be as expected is formed at a central portion in the width direction of one surface of a base film.
Wiring and reinforcing off the entire other surface of the base film
When the film is provided, it is formed on one surface of the base film around the sprocket hole.
Flexible wiring board, characterized in that it comprises a dummy wirings. 2. The flexible wiring board according to claim 1, wherein the thickness of the base film is about 25 μm. 3. A conductive layer is provided on one surface of the base film having such a thickness that the thickness of the sprocket hole portion by itself cannot be as high as expected.
A reinforcing film is provided on the other surface of the base film, sprocket holes are formed on both sides in the width direction of the base film, the conductive layer and the reinforcing film, and the conductive film is formed in a width direction central portion of one surface of the base film. Forming a wiring by a layer, forming a dummy wiring by the conductive layer on one surface of the base film around the sprocket hole, and then peeling off the reinforcing film. Method. 4. The method according to claim 3, wherein the thickness of the base film is about 25 μm.