JPH08335607A - One-layer wiring tcp tape - Google Patents

Abstract

PURPOSE: To obtain TCP strong in a repeated bending test by a method wherein a one-layer wiring TCP tape with no adhesive is composed of a polyimide base film, a copper foil layer and a solder resist coat film of a polyimide solder resist ink. CONSTITUTION: A one-layer wiring TCP tape is formed by using no adhesive with a base film 3 of a thickness 6 to 75μm; a copper foil layer 1 formed with a one-layer wiring layer of a thickness 4 to 25μm and of a pitch between wires 100μm or less; and a solder resist coating layer 2 of a thickness 6 to 60μm covering a wiring layer. The copper foil layer 1 is obtained by casting of the base film 3 and cure heat treatment. After the solder resist coating layer 2 is subjected to the cure heat treatment at 350 deg.C or less, the characteristics are heat pulling strength is 20 to 30kgf/mm<2> and bending elastic coefficient is 3000 to 5000kgf/m<2> . The solder resist coating layer 2 is an epoxy resin ink polyimide system ink.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to TCP (Tape C
TAB (Tape) for Arriage Package
The present invention relates to an Automated Bonding tape, and more particularly to a TCP TAB tape having an adhesive-free single-layer wiring TCP tape having a fine pattern (pitch between wirings is 100 μm or less) between wirings for protection and insulation. .

[0002]

2. Description of the Related Art In a TCP TAB tape, a structure having a coating layer for protection and insulation between wirings is used.
Conventionally, a solder resist ink (epoxy resin) or a polyimide resin ink to be a coating layer is applied to a predetermined thickness of about 20 μm by a printing method and then heated to 120 to 350 ° C. in the atmosphere. Then, the TAB tape for TCP is manufactured by baking for 1 to 5 hours, drying and reactive coagulation to form a coating layer.

However, the conventional TAB tape for TCP has a technical problem. That is, conventionally, photolithography pattern etching was technically possible up to a region where the thickness of the copper foil forming the space between the wirings was 4 μm or more and 35 μm or less and the pitch between the wirings was 100 μm or more. However, in the single-layer wiring thin TCP tape without adhesive, if the pitch between the wirings is 100 μm or less, for example, 80 μm, the photo resist pattern etching cannot be performed in the region where the copper foil thickness is 25 μm or less.

Also, in a single-layer wiring thin TCP tape without adhesive, in a structure having a coating layer for protection and insulation between wirings, a solder resist ink (epoxy resin) or a polyimide resin serving as a coating layer is used. For example, the ink is applied to a predetermined thickness of about 20 μm by a printing method, heated to 120 to 350 ° C. in the atmosphere, cured for 1 to 5 hours, dried, and reactively solidified to form a coating layer. When the TAB tape for TCP is manufactured by forming it, the wiring of the copper foil softens due to heat in the area exceeding 200 ° C., the spring property of the copper foil wiring is deteriorated, and at the same time, the bending property is deteriorated. There is a technical problem that it cannot be used for a single-layer wiring thin TCP tape that requires elasticity and springiness.

Further, there is a technique of forming a TAB tape for TCP on both sides of a conventional metal foil by a screen printing method using, for example, a solder resist ink mainly composed of an epoxy resin paint, but this technique also exceeds 200 ° C. Since the copper foil wiring is softened by heat, the springiness of the copper foil wiring is deteriorated, and at the same time, the flexibility is deteriorated. Therefore, it cannot be used for a single-layer wiring thin TCP tape that requires flexibility and springability. There are technical challenges. As described above, in the conventional single-layer wiring thin TCP tape without an adhesive produced by the conventional manufacturing method, since the curing temperature is as high as 120 to 350 ° C., the wiring of the copper foil is softened by heat, and the copper foil wiring The spring property is reduced, and at the same time, the flexibility is reduced.

[0006]

As described above, according to the conventional one-layer wiring thin TCP tape without adhesive,
When the curing temperature is as high as 350 ° C., there is a problem that the spring property of the copper foil wiring is lowered and, at the same time, the bending property is lowered.

Therefore, the object of the present invention is to prevent the copper foil wiring from being softened by heat even in the region where the curing temperature is 350 ° C., and to reduce the spring property of the copper foil wiring. It is an object to economically provide a single-layer wiring thin TCP tape having flexibility and spring properties without lowering the flexibility.

Further, an object of the present invention is, in particular, in a TAB tape for TCP having a fine pattern (pitch between wirings is 100 μm or less), even if the curing temperature is 350 ° C., the copper foil wiring is heated. Without causing softening due to
A single-layer wiring thin thickness T with good bendability and springability, which does not reduce the springiness or bendability of the copper foil wiring.
To provide CP tape.

Another object of the present invention is to resist the repeated bending test (bending test) and to obtain the T of a single-layer copper foil wiring having a spring property.
To provide CP tape.

[0010]

In order to achieve the above object, the present invention provides a base film having a thickness of 6 to 75 μm and a single wiring layer having a thickness of 4 to 25 μm and a pitch between wirings of 100 μm or less. A one-layer wiring TCP tape having no adhesive is formed by the copper foil layer forming the layer and the solder resist coating layer having a thickness of 6 to 60 μm covering the wiring layer.

In order to achieve the above-mentioned object, the present invention comprises a polyimide-based film, a solder resist coating layer of a polyimide-based solder resist ink, and a copper foil layer to form an adhesive-free single-layer wiring TCP tape. . In this case, the copper foil layer has a tensile strength of 20 to 30 k after the casting and curing heat treatment of the base film and the solder resist coating layer after the heat treatment of 350 ° C. or less.
Bending elastic modulus of 3000 to 5000 kgf at gf / mm ²
A single-layer wiring TCP tape is composed of a copper foil having a thickness of / mm ² .

[0012]

In the present invention, the polyimide-based film, the copper foil layer, and the solder resist coating layer of the polyimide-based solder resist ink are used to form an adhesive-free single-layer wiring T.
Cure heat treatment temperature 3 by constructing CP tape
Even at 50 ° C, the copper foil layer does not soften. The copper foil layer is
The cast film of the base film and the heat treatment for curing, and the heat treatment of the solder resist coating layer at a temperature of 350 ° C. or less have the characteristics of the copper foil having a tensile strength of 20 to 30 kgf.
/ Mm ² bending elastic modulus 3000-5000 kgf / m
By using the copper foil of m ^2, it is possible to realize the one-layer wiring TCP tape which does not soften the copper foil layer even at the curing heat treatment temperature of 350 ° C.

In the present invention, the reason why the thickness of the copper foil layer forming the wiring layer is 4 μm or more and 25 μm or less is that the thickness of the copper foil layer is 35 μm in the region where the pitch between the wirings exceeds 100 μm. Photolithography pattern etching was possible up to the area beyond. However, in a region where the pitch between the wirings is 100 μm or less, the photolithography pattern etching becomes impossible when the thickness of the copper foil layer is 25 μm or more.

In the present invention, the reason why the thickness of the base film is 6 μm or more and 75 μm or less and the thickness of the solder resist coating layer that covers the wiring layer is 6 μm or more and 60 μm or less is one layer TCP without adhesive. In the tape, when the thickness of the base film is 6 μm or more and 75 μm or less,
This is because the flexibility can be maintained without being restricted by the manufacturing method, and the thickness of the solder resist coating layer is for protection between wirings, insulation, and improvement of the flexibility. To guarantee the above, 6μm or more 60μ
It is necessary to secure a thickness of m or less.

In the present invention, in order to guarantee a bending number of 1,000,000 times or more in a repeated bending test (for example, a bending tester of MIT with a bending radius of 2 mm) and to have springiness, a copper foil layer is cured by heat treatment. It is necessary that the copper foil layer does not soften even at a temperature of 350 ° C. Therefore, in the present invention, as a copper foil layer, in the atmosphere
The properties after curing at 350 ° C for 1 to 5 hours have a tensile strength of 20 to 30 kgf / mm ² and, in addition, a flexural modulus of elasticity in order to appropriately hold the bending stress acting on the copper foil layer. It was found that the conventional technical problems can be solved by using a copper foil having 3000 to 5000 kgf / mm ² .

[0016]

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing the TCP tape of the present invention, FIG. 2 is a tensile strength / stretching diagram of various copper foils, and FIG. 3 is a bending stress distribution diagram when the tape is bent. In FIG. 1, 1 is a wiring layer. The copper foil layer to be formed, 2 is a solder resist coating layer, and 3 is a base film.

In the present invention, as shown in FIG. 1, a polyimide base film 3, a solder resist coating layer 2 of a polyimide-based solder resist ink, and a copper foil layer 1 constitute a one-layer wiring TCP tape having no adhesive. To do. in this case,
The copper foil layer 1 has a tensile strength of 20 to 30 kgf after casting and curing heat treatment of the base film, and after the heat treatment of the solder resist coating layer at 350 ° C. or less.
/ Mm ² bending elastic modulus 3000-5000 kgf / m
A one-layer wiring TCP tape is constructed with a copper foil of m ² .

The single-layer wiring TCP having the structure according to the first embodiment of the present invention
By way of background to the discovery of the tape, the method of making the tape of the present invention will now be described. Rolled foil A, electrolytic foil B, electrolytic foil C, and electrolytic foil D were prepared as types of copper foil having a thickness of 18 μm, and polyimide having a thickness of 50 μm was cast on each, and a curing treatment at 350 ° C. was performed. A single-layer wiring TCP tape having a pitch between wirings of 60 μm was manufactured by registration etching. Polyimide solder resist ink (having a flexural modulus of elasticity of the coating layer after curing of 600 kgf / mm @ 2) was applied to the wiring thus obtained by screen printing to a thickness of 20 .mu.m. After coating, step curing was carried out at a curing temperature of 300 ° C. or lower for 3 hours. As a result, the one-layer wiring TCP tape having the structure of the first embodiment is obtained.

Repeated bending tests (bending radius 2) were carried out for each one-layer type wiring TCP tape having the rolled foil A, electrolytic foil B, electrolytic foil C, and electrolytic foil D thus obtained.
mm MIT bending tester). As a result, the number of times of bending was as follows: rolled foil A = 1.2 million times (however, softened and lost the spring property), electrolytic foil B = 950,000 times, electrolytic foil C = 9
50,000 times, electrolytic foil D = 1.2 million times, 100 times of bending
I was able to guarantee 10,000 times. It was the combination of the electrolytic foils D that had the least degree of softening and the most springiness.

Next, the one-layer wiring T of the constitution type of the electrolytic foil D is used.
In the CP tape, the electrolytic foil D has a copper foil thickness of 18 μm and 2
Two types of 5 μm are prepared, each with a thickness of 5 without adhesive.
A 0-μm polyimide casting material was combined to produce a 60-μm pitch between wirings and a single-layer wiring thin TCP tape. Furthermore, polyimide-based solder resist ink (the bending elastic modulus of the coating layer after curing is 600 k
gf / mm ² ) was applied to a thickness of 20 μm by a screen printing method. After coating, step curing was carried out at a curing temperature of 300 ° C. or lower for 3 hours.

Each of the thus obtained single layer type wiring TCP tapes was repeatedly subjected to a bending test (a bending tester for MIT having a bending radius of 2 mm). As a result, the number of times of bending was 1,200,000 times when the copper foil thickness of the electrolytic foil D was 18 μm, whereas the number of times of bending was more than 1 million times when the copper foil thickness of the electrolytic foil D was 25 μm. . The 1-layer type wiring TCP tape of any combination of the copper foils could guarantee the number of bending times of 1 million times. Further, a migration test was carried out at a DC bias of 50 V at 85 ° C. and 85% humidity for 1000 hours. The electrolytic foil D had a copper foil thickness of 18 μm and a single layer type wiring TC.
Both the P tape and the 25 μm single-layer type wiring TCP tape had no dielectric breakdown of the coating layer. As described above, by combining the electrolytic foil D of the present invention, it was possible to supply a one-layer type wiring TCP tape with high reliability of spring property, flexibility and migration resistance.

Here, the tensile strength and flexural modulus of the copper foil layer after polyimide casting and curing for improving the flexibility and after curing the solderless dist coating layer (at a temperature of 350 ° C.) will be described. As shown in the above example, Table 1 shows the results obtained by measuring the tensile strength and the bending elastic modulus of the copper foil layer after the treatment of the produced copper foil at a temperature of 350 ° C.

Further, the tensile strength and elongation of various copper foils of the examples
The diagram is shown in FIG. From these Table 1 and FIG.
As is clear, the electrolytic foil D has good spring properties and flexibility.
Has a tensile strength of 20 to 30 kgf / mm²Flexural elasticity
Coefficient is 3000 to 5000 kgf / mm²To have
found. This bending elastic modulus is 5000 kgf / mm ²
Above, the bending stress due to bending acting on the copper foil layer increases
I know what to do. That is, the curve when the tape in FIG. 3 is bent
Bending stress acting on the copper foil layer as shown in the
Is the bending stress acting on the copper foil layer б = E · ε, where bending strain ε = [one layer wiring TCP tape neutral
Distance to axis C (Approximately one layer wiring TCP tape thickness half
Min)] in [(bending radius R) +1 layer wiring TCP tape
Distance to vertical axis C (Approximately 1 layer wiring half the thickness of TCP tape
Minutes)]. The bending stress б is the copper foil layer.
Yield stress (Plastic deformation of the tensile strength / elongation diagram in Fig. 2
If it is not less than the tensile strength at which it starts, it will break. So
And the bending elastic modulus is 3000 kgf / mm²Copper foil below
, The springiness due to bending is weak (the restoring force at bending is weak.
It will not return to its original shape.)
It cannot be used as a one-layer wiring TCP tape.

In the embodiment of the present invention, the example of the electrolytic copper foil was explained, but the tensile strength of the copper foil layer after being moderately softened under the curing heat treatment condition of the curing heat treatment temperature of 350 ° C. is 20.
Bending elastic modulus is 3,000 to 50 at -30 kgf / mm ^2.
Rolled copper foil may be used as long as it can secure 00 kgf / mm ² .

Further, in the present invention, the TCP tape having a structure having a coating layer for protection and insulation between wirings in the one-layer wiring TCP tape having no adhesive has been described, but the technique of the present invention is flexible. It is also applicable to a one-layer wiring TAB tape for TCP having an adhesive having a structure having a flex resin-based coating layer in which flexibility and flexibility are taken into consideration.

[0026]

As an effect of the present invention, even in a region where the curing temperature is 350 ° C., the wiring of the copper foil does not soften due to heat, and the spring property of the copper foil wiring deteriorates. Thus, it is possible to provide a single-layer wiring thin TCP tape which requires flexibility and spring property without lowering flexibility.

Further, as an effect of the present invention, in particular, in a TAB tape for TCP having a fine pattern (pitch between wirings is 100 μm or less), even if the curing temperature is 350 ° C. A single-layer wiring thin TCP tape having good flexibility and spring properties, which does not cause softening due to heat, and does not reduce spring properties or flexibility of copper foil wiring. You can

Further, as an effect of the present invention, it is possible to provide a TCP tape of a single-layer copper foil wiring which is strong against a repeated bending test (bending test) and has a spring property.

As an effect of the present invention, the TPC tape of the present invention has a high insulation resistance between wirings for liquid crystal drivers or ASICs (insulation resistance of 10 ⁹ after 1000 hours at 85 ° C. and humidity of 85%). It is possible to stably supply a fine wiring (pitch between wirings of 100 μm or less) TCP tape having a high reliability of Ω or more) and to provide it at low cost by mass production.

Further, as an effect of the present invention, T of the present invention
CP tape has a high insulation resistance (85%) between wiring for flexible connection, liquid crystal driver, or ABIS.
Insulation resistance after 10 hours at 85 ° C and 85% humidity is 10
⁹ Ω or more) and so-called flex TAB tape with flexibility and flexible connecting T
In the AB tape, it is possible to provide a highly reliable, highly reliable TAB tape for TCP suitable for fine wiring (pitch between wirings is 100 μm or less).

The effect of the present invention is that the adhesive-free single-layer wiring TCP tape of the present invention is a flexible TAB tape for connection, which is excellent in the spring property (the restoring force at the time of bending is large and returns to the original state immediately). In addition, it is characterized by excellent flexibility and high reliability of flexibility. It is also suitable for TAB tape for fine wiring (pitch between wirings is 100 μm or less) for TPC.

Further, as an effect of the present invention, particularly in a tightly flexible TAB tape having a bending radius of 5 mm or less and having a severe bendability and excellent bending with fine wiring (pitch between wirings is 100 μm or less). The characteristics and springiness (the restoring force at the time of bending is large and returns to the original immediately) are stable.

As another effect of the present invention, the TCP tape of the present invention can be mass-produced in a stable state with a highly reliable TPC tape having high insulation resistance and excellent electrolytic corrosion (migration) resistance. Can be provided.

As described above, the TCP tape of the present invention is particularly suitable for fine wiring (pitch between wirings is 100 μm or less), and has excellent bending characteristics and spring property (the restoring force at the time of bending is large and returns immediately). stable. Since it is strong against repeated bending tests (bending tests) and has springiness, it is possible to provide a highly reliable TAB tape for TCP. Of course, it is possible to economically provide the TCP tape having the one-layer copper foil wiring.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a TCP tape of the present invention.

[Fig. 2] Tensile strength and elongation diagram of various copper foils.

FIG. 3 is a bending stress distribution diagram when the tape is bent.

[Explanation of symbols]

 1. Copper foil layer that forms the wiring layer 1. Solder resist coating layer 3. Base film

Claims (3)

[Claims] 1. A base film having a thickness of 6 to 75 μm,
A copper foil layer forming a single wiring layer having a thickness of 4 to 25 μm and a pitch between wirings of 100 μm or less, and a thickness of 6 to covering the wiring layer.
Adhesive-free single-layer wiring TC characterized by being configured without an adhesive with a solder resist coating layer of 60 μm
P tape. 2. The copper foil layer comprises a base film casting and curing heat treatment, and a solder resist coating layer.
Tensile strength of 2 after curing heat treatment at 50 ℃ or less
Bending elastic modulus 3000 to 50 at 0 to 30 kgf / mm ^2.
The one-layer wiring TCP tape according to claim 1, wherein the TCP tape has a weight of 00 kgf / mm ² . 3. The adhesive-free single-layer wiring TCP tape according to claim 1, wherein the solder resist coating layer is an epoxy resin ink or a polyimide ink.