JP3483238B2 - Film carrier and film carrier device using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film carrier (TAB) for driving a liquid crystal and a film carrier device having an IC mounted thereon.

[0002]

2. Description of the Related Art In recent years, a TAB method using a film carrier suitable for high density and thinning has been increasingly used as a package of a liquid crystal driving IC.

A liquid crystal driving IC is generally used as a film carrier.
As a method of connecting the wires, after aligning the lead formed of a conductor such as copper of the film carrier with the Au bump formed on the IC chip electrode, a bonding tool is applied from the opposite side of the lead surface for joining the lead and the bump. It is common to bond by heating and pressurizing using.

Therefore, in a conventional film carrier for connecting an IC, as shown in FIG. 1, a hole (device hole) 2 for connecting an IC is formed in advance in an insulative film (base film) 1 such as a polyimide resin. It is provided by punching, and the inner lead 3 is overhanged in the device hole and aligned with the Au bump formed on the IC chip electrode. Then, a bonding tool is applied from the opposite side of the lead surface for joining the lead and the bump. The method of joining by heating and pressurizing is generally used. Then, the connected IC is sealed with an epoxy-based IC sealing resin to ensure reliability.

Further, there are the following two methods for connecting the film carrier to a printed circuit board or the like. A hole (outer hole) 4 is formed at a predetermined place on the base film by punching or the like, and an outer lead 5 is further formed in the outer hole portion. After connecting the ICs by the above method, the film carriers are cut one by one, When it is desired to reduce the mounting space of the liquid crystal panel, the liquid crystal panel is bent at the bending portion 9 and then connected to the printed board by soldering or the like.
Further, in recent years, there is a method in which the outer lead 5 is directly formed on the base film without forming a hole (outer hole) and the anisotropic conductive film is used to heat and connect to the printed board.

Then, in the wiring pattern other than the portion contributing to the above-mentioned bonding, the solder is not bridged at the time of soldering, and the reliability is deteriorated due to pattern short-circuit, corrosion, electromigration and whiskers due to conductive foreign matter. In order not to cause it, Sn
In general, an overcoat agent is applied before IC connection in order to mask an unnecessary portion of pattern finish plating with Au, solder, or the like.

In this case, as one of the characteristics required for the overcoating agent, the adhesiveness with the epoxy type encapsulating resin treated to secure the reliability of the IC is extremely important. When an overcoating agent having low adhesion to the sealing resin is used, there is a high risk that the adhesive surface will be peeled off by an external force at the manufacturing stage of the film carrier package or a bending force at the time of mounting.

Further, in the case of a film carrier having a high-density pattern, the warp of the film carrier caused by the difference in the thermal contraction rate and the thermal expansion rate between the overcoating agent and the insulating polyimide film, especially the yield when joining the outer leads. And causes a decrease in reliability. Therefore, one of the important properties required for the overcoat agent is that the curing shrinkage is small, that is, the warpage is small.

Further, in the case of a high-density pattern, the conductor width of the wiring pattern becomes significantly smaller than that of the conventional one. Therefore, as a characteristic required for the overcoat agent, the adhesion to the conductor surface such as copper is also important. If the adhesion is poor, the components in the plating permeate into the ends of the overcoat agent in the plating step after the application of the overcoat agent, and copper or the like corrodes. As a result, migration occurs and reliability decreases.

Further, recently, due to the large screen of liquid crystal,
Bending and mounting for the purpose of reducing the frame of the panel is rapidly progressing. In that case, it is necessary to remove a part or all of the insulating film in the bent portion and apply a highly flexible overcoat agent to the bent portion. If an overcoating agent with low flexibility is used, cracks may occur in the overcoating agent during bending mounting or repair and the wiring pattern may be broken, or the back tension may increase during holding after bending, which may cause damage to the wiring of the film carrier and the substrate. A fatal defect occurs that the connection part of is peeled off.

As an overcoating agent for such a film carrier, conventionally, an epoxy-based overcoating agent (for example, CCR-232GF manufactured by Asahi Chemical Research Institute) is used.
And a polyimide-based overcoating agent (for example, FS-100L manufactured by Ube Industries, Ltd.) are used, but the adhesiveness with the above resin is high, the warpage is small, and the flexibility is high. There is no coating agent, and it is necessary to apply a plurality of overcoating agents in combination (JP-A-6-283575).

In FIG. 1, 6 is an epoxy type overcoating agent (CCR-232G) which is excellent in adhesion to a sealant and copper.
F) is applied, and 7 is applied with a polyimide-based overcoating agent (FS-100L) having high flexibility and less shrinkage.

However, in this case, in order to apply a plurality of overcoat agents, a plurality of coating steps are required, which not only results in a significant decrease in productivity and a decrease in yield but also an increase in cost, but also a constraint on the film carrier design. Will increase
It becomes an expensive and economical film carrier.

[0014]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. It has a high productivity and a high yield, is economical, and does not reduce the adhesiveness to the IC encapsulating resin, so that the warpage can be prevented. An object of the present invention is to provide a film carrier and a film carrier device which are remarkably small and have high flexibility and are highly reliable even when they are folded and used.

[0015]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above object, the present inventors have found that an overcoating agent containing a urethane resin as a main component is formed on the wiring pattern surface side other than the connecting portion including the bent portion. It has been found that by applying the composition, a warp can be remarkably reduced without lowering the adhesion with the IC encapsulating resin, and a highly flexible film carrier and a film carrier device can be obtained even when used by being bent and having high flexibility. The present invention has been completed.

That is, the film carrier of the present invention has a pattern formed of an insulating film and a metal foil film on the insulating film, and a part or all of the insulating film at the bent portion is removed for driving liquid crystal. In the film carrier of (1) , the (A) number average molecular weight is 1000 to 8000 on the side of the wiring pattern surface other than the connection portion including the bent portion , and
Polybutadiene having 2 to 10 hydroxyl groups per molecule
Polyol, (B) number average molecular weight 13,000-300
00, poly having 2 to 10 hydroxyl groups per molecule
Ester polyol and (C) number average molecular weight of 1000
~ 8000, having 2-10 hydroxyl groups per molecule
Essential polybutadiene polyblock isocyanate
And the weight ratio of the polyol is the solid content (A):
(B) = 40: 60 to 90:10, polyblock
The amount of isocyanate (C) is the total hydroxyl equivalent of the polyol
On the other hand, an overcoat agent containing a urethane resin as a main component containing 0.8 to 3.5 equivalents is applied. The film carrier device of the present invention is characterized by using such a film carrier.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The film carrier of the present invention and the film carrier device using the same will be described below in detail with reference to the drawings. FIG. 2 is a plan view of a film carrier for a liquid crystal driver of the present invention, in which the same reference numerals as those in FIG. 1 indicate the same things, and 8 is a urethane-based overcoating agent. As shown in the figure, part or all of the insulating film 1 is previously removed by punching, polyimide etching or the like to provide a device hole 2, an outer hole 4 and a bent portion 9.

Examples of the insulative film used here include polyimide resin, glass epoxy resin, BT resin, polyester tape and the like, but polyimide resin is preferably used in consideration of processability and characteristics. The means for providing the removed portion on the insulating film is not limited to punching and polyimide etching, and is arbitrary. The metal thin film is not particularly limited as long as it is a conductive thin film capable of forming a conductor pattern, but a copper foil is generally used. Usually, an electrolytic copper foil having a predetermined thickness is bonded to a base film by using an epoxy adhesive or the like, and heated in an oven to be laminated.

Next, a photoresist is applied, developed and etched on the laminated copper foil in accordance with a conventional method, and then an overcoating agent is applied by screen printing to the wiring pattern surface side other than the connection portion including the bent portion. To a predetermined thickness, usually in an oven at 120-160 ° C, 1
Heat for ~ 2 hours to form a film carrier.

In the present invention, a composition containing a urethane resin as a main component is used as the overcoat agent. That is, this composition has as a component (A) a number average molecular weight of 1
000 to 8,000, polybutadiene polyol having 2 to 10 hydroxyl groups per molecule, (B) number average molecular weight of 13,000 to 30,000, and 2 to 10 per molecule.
Polyester polyol having one hydroxyl group and (C)
Number average molecular weight is 1000-8000 and 2 per molecule
Polybutadiene polyblock isocyanate having 10 to 10 hydroxyl groups is an essential component, and the weight ratio of polyol is (A) :( B) = 40: 60 to 90: 1 in solid content.
It is 0, and the amount of the polyblock isocyanate (C) is 0.8 to 3.5 equivalent to the total hydroxyl equivalent of the polyol.

The component (A) is important for imparting both the characteristics found in the rigid resin such as heat resistance and chemical resistance, and the characteristics found in the flexible resin such as flexibility and low shrinkage. . If the molecular weight is smaller than this range or the number of hydroxyl groups per molecule is larger than this range, the crosslink density during curing will be higher, resulting in a harder cured product and the flexibility of the cured coating film. Sufficient physical properties cannot be obtained with respect to low shrinkage during curing. On the other hand, when the molecular weight is larger than this range or when the number of hydroxyl groups per molecule is smaller than this range, the crosslinking density at the time of curing becomes low, resulting in a more flexible cured product, while curing The heat resistance and chemical resistance of the coating film are significantly reduced. Further, since the component (A) has a polybutadiene skeleton, it has an effect of further improving flexibility and low shrinkage upon curing.

The component (B) imparts the characteristics found in a flexible cured product such as improved flexibility and low shrinkage at the time of curing, and also has the effect of the highly polar ester bond contained in the resin skeleton to form a base. It is important to improve the adhesion.

The component (C) is important for imparting both the characteristics found in the rigid resin such as heat resistance and chemical resistance and the characteristics found in the flexible resin such as flexibility and low shrinkage. If the molecular weight is smaller than this range or the number of hydroxyl groups per molecule is larger than this range, the crosslink density during curing will be higher, resulting in a harder cured product and the flexibility of the cured coating film. Sufficient physical properties cannot be obtained with respect to low shrinkage during curing. On the other hand, when the molecular weight is larger than this range or when the number of hydroxyl groups per molecule is smaller than this range, the crosslinking density at the time of curing becomes low, resulting in a more flexible cured product, while curing The heat resistance and chemical resistance of the coating film are significantly reduced. Further, since the component (A) has a polybutadiene skeleton, it has an effect of further improving flexibility and low shrinkage upon curing.

When the polybutadiene polyol (A) alone is cured with the polybutadiene polyisocyanate (B), a cured product having a relatively good balance of heat resistance, chemical resistance and flexibility, and low shrinkage upon curing is obtained. However, it is necessary to combine it with the polyester polyol (B) because it is a level that cannot be said to be fully satisfactory in terms of flexibility, low shrinkage upon curing, and adhesion to the base. That is, (A) :( B) = 4
It is preferable to use a mixture in the range of 0:60 to 90:10. When the amount of the polyol (A) is less than this range, the crosslinking density is too low, and thus the coating film has properties such as heat resistance and chemical resistance. Is significantly reduced. In addition, the amount of polybutadiene polyblock isocyanate (C) is preferably 0.8 to 3.5 equivalents relative to the total hydroxyl equivalents of the polyol, and the crosslinking density decreases when the amount is more or less than this. Since it is too much, the properties such as heat resistance and chemical resistance of the coating film are significantly deteriorated.

In the present invention, in addition to the above essential elements, a curing accelerator for polyol and isocyanate, a filler, an additive, a thixotropic agent, a solvent and the like may be added, if necessary. In particular, it is preferable to add rubber fine particles in order to further improve the bending resistance, and further improve the adhesion with the underlying copper circuit, a base substrate such as polyimide or polyester film, or the adhesive layer. Therefore, it is preferable to add polyamide fine particles. Generally, the overcoating agent is generally applied by printing after forming a wiring pattern by a screen printing method and then cured at a predetermined temperature, but it may be applied after a plating treatment such as tin plating or gold plating.

The thickness of the overcoating agent applied in this manner is 5 μm or more and 60 μm or less, preferably 10 μm.
It is preferably 30 μm or less. When the thickness is less than 5 μm, the copper pattern under the overcoat agent is discolored due to the permeation of the components of the plating solution into the coating film, which is unfavorable because the reliability is lowered. On the other hand, if it is thicker than 60 μm, the warpage becomes large due to curing shrinkage, and a problem occurs in package mounting, which is not preferable.

The film carrier device of the present invention uses the film carrier thus obtained,
It is made by connecting an IC to this and sealing with an epoxy-based IC sealing resin or the like.

[0028]

As described above, according to the present invention, productivity is improved by adopting the overcoating agent containing urethane resin as a main component on the wiring pattern surface side other than the connection portion including the bent portion of the film carrier. It is possible to obtain a film carrier and a film carrier device which have a high yield and are economical and which have a significantly small warpage without lowering the adhesiveness to the IC sealing resin, have high flexibility, and have high reliability even when they are bent and used.

[0029]

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

[0030]

Example 1 As shown in FIG. 2, in a film carrier for a liquid crystal driver having a bent portion 9,
A 75 μm polyimide resin (trade name, manufactured by Upilex S Ube Industries, Ltd.) is used as the base film 1.
The device hole 2 and the outer hole 4 and the bend removing portion 9 are provided by punching, respectively. Next, an electrolytic copper foil (trade name, FX-VLP manufactured by Mitsui Mining & Smelting Co., Ltd.) having a thickness of 18 μm was adhered to the base film with an epoxy adhesive (trade name X, manufactured by Tomagawa Paper Manufacturing Co., Ltd.), and placed in an oven. Heated and laminated.

Next, a photoresist is coated, developed and etched on the laminated copper foil by a conventional method, and then an overcoating agent is applied by screen printing to the wiring pattern surface side other than the connection portion including the bent portion. Urethane resin (trade name, AE-70-Mll Ajinomoto Co., Inc.)
Manufactured to a thickness of 20 μm and heated at 150 ° C. for 1 hour to prepare a film carrier as shown in FIG.

An IC is connected to this film carrier, and an epoxy type IC sealing resin (trade name, CEL-C-5020) is used.
-D20 manufactured by Hitachi Chemical Co., Ltd.) to form a film carrier device. The magnitude of warpage was measured for this film carrier device.

The measurement of the magnitude of the warp is carried out by using a measuring fine scope (MF-1) as a measuring machine.
00: manufactured by Mitutoyo Co., Ltd., and the measurement sample is the individual piece obtained in Example 1 (sample cut into one piece).
Was used.

First, the measurement sample is placed on the table of the measuring device with the surface of the base material facing upward, and then the table surface is set to the reference position (0 mm), and the curved height of the central portion in the width direction of the device hole portion is set. Was measured.

The height of the warp depends on the Measuring Fi
With ne Scope, measure the height by focusing on the curved part of the widthwise center of the tape,
The obtained height was defined as the amount of warpage.

Further, after bending and mounting on a substrate, a voltage of 100 V is applied at a temperature of 85 ° C. and a humidity of 85% to obtain 100
The insulation resistance after 0 hours was measured. The insulation resistance is 10
^A defect of ⁸ Ω or less was regarded as a defect, and the number of defective products out of 20 was evaluated.
As a result, the warpage was as good as 1 mm or less, the number of defects when bent and mounted on the substrate was zero, and the number of defects was zero even after 1000 hours.

[0037]

Comparative Example 1 Twenty film carrier devices were prepared by the same materials and process as in Example 1 except that an epoxy type (trade name: CCR-232GF, manufactured by Asahi Chemical Laboratory) was used as an overcoat agent.

The film carrier device thus obtained was evaluated in the same manner as in Example 1.
The warpage was as large as 2.2 mm, and two wires were broken when further bent and mounted on the substrate, and a total of eight pieces became defective after 1000 hours.

[0039]

[Comparative Example 2] Twenty film carrier devices were prepared by the same materials and process as in Example 1 except that a polyimide type (trade name: FS-100L, manufactured by Ube Industries) was used as an overcoat agent.

When the film carrier device thus obtained was evaluated in the same manner as in Example 1,
The warp was as good as 1 mm or less, but after bending and mounting on the substrate for 1000 hours, a total of 10 pieces became defective. The yield as a film carrier was also 2% worse than that in Example 1.

[0041]

[Comparative Example 3] An epoxy type (trade name CCR-232GF, manufactured by Asahi Chemical Laboratory) was used as an overcoating agent around the device hole, and a polyimide type (product Name FS-100
L, manufactured by Ube Industries, Ltd., except that the film carrier device was formed by the same material and process as in Example 1 except that
I made 0.

As a result, the warp was as good as 1 mm or less, and the number of defects when bent and mounted on the substrate was zero, and 10
The number of defective products was zero even after 00 hours, but the yield as a film carrier was 9% worse than that in Example 1.

[Brief description of drawings]

FIG. 1 shows a plan view of a conventional film carrier.

FIG. 2 shows a plan view of the film carrier of the present invention.

[Explanation of symbols]

1: Insulating film, 2: Device hole, 3: Inner lead, 4: Outer hole, 5: Outer lead,
6: Epoxy-based overcoat agent, 7: Polyimide-based overcoat agent, 8: Urethane-based overcoat agent,
9: Bent portion.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Oribe 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Ajinomoto Co., Inc. Central Research Laboratory (72) Inventor Tadahiko Yokota 1 Suzuki-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa -1 Central Research Institute of Ajinomoto Co., Inc. (56) Reference JP-A-5-3228 (JP, A) JP-A-7-122597 (JP, A) JP-A-5-267397 (JP, A) (58) ) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/60 311

Claims (2)

(57) [Claims] 1. A film carrier for driving a liquid crystal, comprising an insulating film and a pattern formed of a metal foil film on the insulating film, and part or all of the insulating film in the bending part is removed. (A) the number average molecular weight is 1000 to 80 on the side of the wiring pattern other than the connection portion including
00, poly having 2 to 10 hydroxyl groups per molecule
Butadiene polyol, (B) number average molecular weight is 1300
0-30000, 2-10 hydroxyl groups per molecule
Polyester polyol having and (C) number average molecular weight
Is 1000-8000 and 2-10 water per molecule
Polybutadiene Polyblock Isocyanate Having Acid Group
Is an essential component, and the weight ratio of the polyol is solid odor.
(A) :( B) = 40: 60 to 90:10,
The amount of reblocked isocyanate (C) is the total amount of polyol
A film carrier characterized by being coated with an overcoating agent containing a urethane resin as a main component , the content being 0.8 to 3.5 equivalents relative to the hydroxyl equivalents . 2. A film carrier device using the film carrier according to claim 1.