KR19990023968A - Film carrier and film carrier device using the same - Google Patents

Abstract

The present invention provides a film carrier and a film carrier device that is highly reliable even when folded and used with high flexibility and high flexibility without sacrificing productivity and yield, being economical, and reducing adhesion to IC sealing resin. In the film carrier for liquid crystal drive which has the pattern formed by the insulating film and the metal thin film on it, and the one part or all part of the insulating film of the bending part is removed, As a solution means, the bending part is carried out. Provided are a film carrier and a film carrier device using the film carrier, wherein an overcoat agent containing a urethane resin as a main component is applied to a wiring pattern surface other than the connecting portion to be included.

Description

Film carrier and film carrier device using the same

The present invention relates to a film carrier (TAB) for liquid crystal driving and a film carrier device in which an IC is mounted thereon.

In recent years, the TAB method using the film carrier suitable for densification and thickness reduction is increasingly used as a package of liquid crystal drive IC.

In general, a method of connecting a liquid crystal driving IC to a film carrier, wherein a lead formed of a conductor such as copper of a film carrier is aligned with an Au bump formed on an IC chip electrode, and then from the opposite side of the lead surface to which the lead and bump are joined. It is common to join by heating and pressure using a bonding tool.

Therefore, in the film carrier which connects an IC conventionally, as shown in FIG. 1, the hole (device hole) 2 for connecting an IC to insulating film (base film) 1, such as polyimide resin, is previously made. Formed by punching or the like, and the inner hole 3 of the device hole is overhanged and aligned with the Au bump formed on the IC chip electrode, and then the bonding tool is placed from the opposite side of the lead surface where the lead and bump are joined. The method of joining by heating and pressurizing using is common. The connected IC is sealed by an epoxy IC sealing resin to ensure reliability.

In addition, there are two methods for connecting the film carrier to a printed board or the like. Holes (outer holes) 4 are formed in a predetermined place on the base film by punching or the like, and outer cells 5 are formed in the outer hole portions, and the film carriers are formed one by one after connecting the IC by the above method. In the case of cutting and reducing the panel mounting space of the liquid crystal, the sheet is folded in the bending portion 9 and connected to the printed circuit board by soldering or the like. In recent years, there is a method in which an outer 5 is formed directly on a base film without forming a hole (outer hole), and is heated and connected to a printed circuit board using an anisotropic conductive film.

In addition, in the wiring patterns other than the portions contributing to the bonding, the solder is not bridged during soldering, and the reliability caused by the occurrence of pattern shorting, corrosion, electromigration, and whisker by conductive foreign matters does not deteriorate. In order to mask the unnecessary part of pattern finishing plating by Sn, Au, and solder, it is common to apply an overcoat agent before IC connection.

In this case, as one of the characteristics required for the overcoat agent, adhesion to the epoxy-based sealing resin to be treated for securing the reliability of the IC is very important. When the overcoat agent with low adhesiveness with a sealing resin is used, there exists a high risk that an adhesive surface may peel off by the external force in the manufacturing step of a film carrier package, or the bending force at the time of mounting.

In addition, in a film carrier having a high density pattern, the warp of the film carrier caused by the difference in thermal contraction rate and thermal expansion rate between the overcoat agent and the insulating polyimide film, in particular, reduces yield and reliability when joining an outer cell. It is a cause. For this reason, one of the important characteristics required for the overcoat agent is that the hardening shrinkage is small, i.e., the warpage is small.

When the high density pattern is formed, the conductor width of the wiring pattern is also significantly smaller than in the related art. Therefore, as properties required for the overcoat agent, adhesion to conductor surfaces such as copper is also important. In the case of poor adhesion, a component of the conductive metal penetrates into the end portion of the overcoat agent during the plating step after the overcoat is also coated, and copper or the like corrodes. As a result, migration occurs and reliability is lowered.

Moreover, in recent years, bending and mounting of the frame of a panel for the purpose of making a big screen of liquid crystals are rapidly progressing. In this case, it is necessary to remove a part or all of the insulating film of the part to be bent, and apply the high flexibility overcoat agent to the part to be bent. If a low-flex overcoat agent is used, cracks may occur in the overcoat agent during bending or repairing, resulting in disconnection of the wiring pattern or high back tension during holding after bending, and the connection between the film carrier wiring and the substrate A fatal defect that is said to be peeled off occurs.

As such an overcoat agent for film carriers, conventionally, an epoxy-based overcoat agent (for example, CCR-232GF manufactured by Asahi Chemical Research Institute, Japan) and a polyimide-based overcoat agent (for example, Japan and Ubekosan FS) -100L) and the like are used, but there is no overcoat agent that satisfies the characteristics of high adhesion to the resin, less warpage, and high flexibility, and it is necessary to apply a plurality of overcoat agents in combination. Japanese Patent Laid-Open No. 6-283575).

In Fig. 1, (6) is coated with an epoxy-based overcoat agent (CCR-232GF) excellent in adhesion to a sealant or copper, and (7) is a polyimide-based overcoat agent (FS-100L) with high flexibility and low shrinkage. Is applied.

In this case, however, in order to apply a plurality of overcoat agents, a plurality of application steps are required, not only cost increases due to a significant decrease in productivity and a decrease in yield, but also a lot of constraints on the film carrier design, which are expensive and economical. It is not a film carrier.

The present invention has been made to solve the problems of the prior art, and the productivity and yield are high, economical, and there is no deterioration in adhesion with the IC sealing resin, the warpage is remarkably small, the flexibility is high, and the reliability can be used even when folded. It is an object to provide this high film carrier and film carrier device.

1 is a plan view of a conventional film carrier

2 is a plan view of a film carrier of the present invention

Explanation of symbols for main parts of drawings

1: insulating film 2: device hole

3: inner lead 4: outer hole

5: outer 6 6: epoxy overcoat

7: polyimide-based overcoat agent 8: urethane-based overcoat agent

9: bending part

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to achieve the said objective, the present inventors apply | coated the overcoat agent which consists of urethane resin as a main component to the wiring pattern surface other than the connection part containing a bending part, without degrading adhesiveness with IC sealing resin. The present inventors have found that a film carrier and a film carrier device with high reliability can be obtained even when the warpage is remarkably small and the flexibility and bending are used, and the present invention has been completed.

That is, the film carrier of the present invention has a pattern formed by an insulating film and a metal thin film thereon, and in the film carrier for liquid crystal driving in which part or all of the insulating film of the bent portion is removed, the film carrier includes a bent portion. An overcoat agent containing a urethane resin as a main component is applied to a wiring pattern surface other than the connecting portion.

Moreover, the film carrier device of this invention used such a film carrier, It is characterized by the above-mentioned.

EMBODIMENT OF THE INVENTION Hereinafter, the film carrier of this invention and the film carrier device using this are demonstrated in detail using drawing.

Fig. 2 is a plan view of the film carrier for the liquid crystal driver of the present invention, in which the same reference numerals as in Fig. 1 indicate the same, and (8) is a urethane-based overcoat agent.

As shown in the drawing, part or all of the insulating film 1 is previously removed by punching, polyimide etching, or the like, so that the device hole 2, the outer hole 4 and the bent portion 9 are formed. have.

Examples of the insulating film used herein include polyimide resins, glass epoxy resins, BT resins, polyester tapes, and the like, but polyimide resins are preferably used in consideration of workability and characteristics. The means for forming the removed portion in the insulating film is not limited to punching or polyimide etching, but is optional.

In addition, the metal thin film is not particularly limited as long as it is a conductive one capable of forming a conductor pattern, but copper foil is generally used.

Usually, the electrolytic copper foil of predetermined thickness is adhere | attached on a base film using an epoxy adhesive etc., and it heats in an oven and laminates.

Next, a photoresist is applied, developed, and etched on the copper foil after lamination according to a conventional method, and then the overcoat is applied to a predetermined thickness by screen printing on the side of the wiring pattern other than the connecting portion, and the ordinary coating is applied to a predetermined thickness. 120-160 degreeC is heated in oven for 1 to 2 hours, and a film carrier is formed.

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 a polybutadiene polyol having (A) number average molecular weight of 1000 to 8000 as a component, 2 to 10 hydroxyl groups per molecule, (B) number average molecular weight of 13000 to 30000, and 2 per molecule. A polyester polyol having ˜10 hydroxyl groups and a polybutadiene polyblock isocyanate having a number average molecular weight of 1000 to 8000 and having 2 to 10 hydroxyl groups per molecule as essential components, and the weight ratio of the polyol A) :( B) = 40: 60-90: 10, and the quantity of polyblock isocyanate (C) contains 0.8-3.5 equivalent with respect to the total hydroxyl equivalent of a polyol.

The component (A) is important for imparting both the properties seen in rigid resins such as heat resistance and chemical resistance, and the properties seen in flexible resins such as flexibility and low shrinkage. When the molecular weight becomes smaller than this range, or when the number of hydroxyl groups per molecule becomes larger than this range, the crosslinking density at the time of curing increases, which results in a more cured product, which is more suitable for flexibility of the cured coating film and low shrinkage at the time of curing. Sufficient physical properties can not be obtained. 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 is lowered, resulting in a more flexible cured product, while the heat resistance and chemical resistance of the cured coating film. Significantly lowers. In addition, since the bicomponent (A) is a polybutadiene skeleton, there is an effect of further improving flexibility and low shrinkage at the time of curing.

The component (B) is important for improving flexibility and low shrinkage at the time of curing, and at the same time, improving the adhesion to the base from the influence of the highly polar ester bonds contained in the resin skeleton. Do.

The component (C) is important for giving both the properties seen in rigid resins such as heat resistance and chemical resistance, and the properties seen in flexible resins such as flexibility and low shrinkage. When the molecular weight becomes smaller than this range, or when the number of hydroxyl groups per molecule becomes larger than this range, the crosslinking density at the time of curing increases, which results in a more cured product, which is more suitable for flexibility of the cured coating film and low shrinkage at the time of curing. Sufficient physical properties can not be obtained. 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 is lowered, resulting in a more flexible cured product, while the heat resistance and chemical resistance of the cured coating film. Significantly lowers. Moreover, since the bicomponent (A) is a polybutadiene skeleton, there exists an effect which improves flexibility and the low shrinkage at the time of hardening further.

When only the polybutadiene polyol (A) is cured with polybutadiene polyisocyanate (B) alone, it is relatively a satisfactory characteristic of heat resistance, chemical resistance and flexibility, low shrinkage at the time of curing, and adhesion to the base. Since it is an unspeakable level, it is necessary to combine with polyester polyol (B). That is, it is preferable to mix and use in the range of (A) :( B) = 40: 60-90: 10, and when polyol (A) is less than this range, since crosslinking density will fall too much, Characteristics, such as heat resistance and chemical resistance, fall remarkably. In addition, the amount of polybutadiene polyblock isocyanate (C) is preferably 0.8 to 3.5 equivalents relative to the total hydroxyl group equivalent of the polyol. The properties such as heat resistance, chemical resistance and the like significantly decrease.

In addition to the above essential elements, the present invention may be added with a curing accelerator of a polyol and an isocyanate, a filler, an additive, a thixotropic agent, a solvent, and the like, as necessary. In particular, in order to further improve the bending resistance, it is preferable to add rubber fine particles, and in order to further improve the adhesion between the base copper circuit of the base, polyimide, polyester film and the like, and adhesive layer further Preference is given to adding polyamide particulates.

Usually, the overcoat agent is printed and applied after the wiring pattern is formed by the screen printing method, and then cured at a predetermined temperature thereafter, but may be after plating treatment such as tin plating or gold plating.

Thus, the thickness of the overcoat agent apply | coated is 5 micrometers or more and 60 micrometers or less, Preferably 10 micrometers or more and 30 micrometers or less are preferable. If it is less than 5 µm, discoloration occurs in the copper pattern under the overcoat agent due to the penetration of the plating liquid component into the coating film, resulting in a decrease in reliability and undesirable. Moreover, when it is thicker than 60 micrometers, curvature becomes large by hardening shrinkage, and a problem arises in package mounting, and it is not preferable.

Moreover, the film carrier device of this invention uses the film carrier obtained in this way, connects IC to this, and is made by sealing with epoxy type IC sealing resin etc.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated concretely based on an Example and a comparative example.

(Example 1)

As shown in Fig. 2, in the film carrier for the liquid crystal driver having the bent portion 9, as the base film 1, a polyimide resin of 75 mu m (trade name, Eupyrex S, Japan, Ubekosan ( Product), and the device hole 2, the outer hole 4, and the bending removal part 9 were formed by punching, respectively. Next, an electrolytic copper foil (trade name, FX-VLP, Japan, Mitsui Kinzoku Kogyo Co., Ltd.) having a thickness of 18 μm was applied to the base film, and an epoxy adhesive (trade name X, Japan, Tomoegawa Seishi Co., Ltd.) ), It was heated in an oven and laminated.

Next, a photoresist is applied, developed, and etched on the copper foil after lamination according to a conventional method, and then urethane resin (trade name, AE) is formed by screen printing on the surface of the wiring pattern other than the connection portion including the folded portion. -70-M11, Japan, and Ajinomoto Co., Ltd.) were applied so as to have a thickness of 20 µm, and heated at 150 ° C for 1 hour to prepare a film carrier as shown in FIG.

An IC was connected to this film carrier and sealed with an epoxy IC sealing resin (trade name, CEL-C-5020 D20, Japan, Hitachikasei Co., Ltd.) to make a film carrier device. The magnitude | size of the curvature with respect to this film carrier device was measured.

The size of this warp is measured using Measuring Fine Scope (MF-100: manufactured by Mitsutoyo Co., Ltd.) as a measuring instrument, and the measuring sample is a single piece (sample cut into one piece) obtained in Example 1. Was used.

First, the measurement sample was placed with the base material face up on the table of the measuring instrument, and then the curved height of the central portion in the width direction of the device hole portion was measured with the table surface as the reference position (0 mm).

The height of curvature measured the height by focusing on the curved point of the center part of the width direction of a tape by Measuring Fine Scope, and made the height obtained the curvature amount.

Furthermore, it was bent and mounted on the board | substrate, and the voltage of 100V was applied at 85 degreeC of humidity of 85%, and the insulation resistance after 1000 hours was measured. Insulation resistance was 10 ⁸ Ω or less, and evaluated based on the number of defects in 20 pieces.

As a result, the warpage was good at 1 mm or less, the number of defects when folded and mounted on the substrate was zero, and the number of defects was zero even after 1000 hours.

Comparative Example 1

20 film carrier devices were produced by the material and the process similar to Example 1 except having used the epoxy type (brand name CCR-232GF. Japan, Asahi Kagaku Research Institute) as an overcoat agent.

The film carrier devices thus obtained were subjected to the same evaluation as in Example 1, and the warpage was 2.2 mm, which was larger when folded and bent and mounted on a substrate. done.

Comparative Example 2

20 film carrier devices were produced by the material and the process similar to Example 1 except having used the polyimide system (brand name FS-100L, Japan, made by Ubeko-Ox Inc.) as an overcoat agent.

The film carrier devices thus obtained were subjected to the same evaluation as in Example 1, but the warpage was good at 1 mm or less. However, the film carrier devices were further folded and mounted on the substrate, resulting in a total of 10 defects after 1000 hours. Moreover, the yield as a film carrier also fell 2% compared with Example 1.

Comparative Example 3

Polyimide (trade name FS-100L, Japan) is used as the overcoat agent in the peripheral part of the device hole using an epoxy-based (trade name CCR-232GF, Japan, manufactured by Asahi Kagaku Research Institute), and other portions including the bend. 20 film carrier devices were produced by the material and the process similar to Example 1 except having apply | coated the thing of Ubekosan Co., Ltd. product.

As a result, the warpage was good at 1 mm or less, the number of defects when folded and mounted on the substrate was zero, and the number of defects was zero after 1000 hours, but the yield as a film carrier was 9% worse than that in Example 1.

As described above, according to the present invention, by adopting an overcoat 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, the productivity and yield are high, and the economic and adhesiveness with the IC sealing resin is reduced. It is possible to obtain a highly reliable film carrier and a film carrier device even if the bending is remarkably small, the flexibility is high, and the sheet is used without being folded.

Claims (2)

In a film carrier for liquid crystal driving having a pattern formed by an insulating film and a metal thin film thereon, and part or all of the insulating film of the bent portion is removed, a urethane resin on the surface of the wiring pattern other than the connecting portion including the bent portion. The film carrier which apply | coated the overcoat agent which has a main component as a main component. The film carrier device using the film carrier of Claim 1.