KR100509109B1 - Composition for Use in the Formation of Anisotropic Conductive Film - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition capable of forming an anisotropic conductive film that can be used as a connection material between modules when mounting various display devices including a liquid crystal display device (LCD) and a semiconductor device. An anisotropic conductive film composed of an acrylated epoxy resin, a radical polymerizable compound, an acrylic rubber, a radical initiator, an epoxy curing agent, an amine group-containing phosphorus compound, and conductive particles, wherein the anisotropic conductive film formed from the composition of the present invention is applied to a substrate in a wide temperature range. Since it shows high adhesive strength and maintains excellent reliability even at high temperature and high humidity conditions, it is used to interconnect the panel substrate of the liquid crystal display device and the external driving circuit board to provide a high reliability product by exhibiting constant physical properties without changing the initial adhesive strength. can do.

Description

Composition for Use in the Formation of Anisotropic Conductive Film}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition capable of forming an anisotropic conductive film that can be used as a connection material between modules when mounting various display devices including liquid crystal displays (LCDs) and semiconductor devices, and more particularly, in a wide temperature range. The present invention relates to a resin composition for anisotropic conductive films that exhibits high adhesion to various kinds of substrates and is excellent in reliability such as moisture resistance and heat resistance.

In recent years, anisotropic conductive films have been widely used as materials for electrically connecting electronic components such as semiconductor devices and circuit boards. The use of anisotropic conductive films is becoming more diversified in accordance with the trend toward thinner and shorter electronic components. In recent years, computer monitors as well as televisions have become thinner and thinner. A connection method using an anisotropic conductive film (ACF) is widely used. Among them, in particular, the use of ACF in LCD mounting technology is deepening, and a method of directly mounting a semiconductor circuit on a film or a glass substrate by a COF (Chip On Film) or COG (Chip on Glass) method is rapidly developing. Examples of patents related to such an anisotropic conductive film include Japanese Patent Laid-Open Nos. 5-21094, 5-5-020020, 7-302666, 7-302667, 7-211374, 8-311420, and 9-199206, and 9-115335.

The anisotropic conductive film is basically composed of conductive particles and insulating resin. Carbon particles were initially used as the particles exhibiting electrical conductivity, and then solder balls were used, and now nickel balls or silver balls are mainly used. The reason why silver is used as the conductive material is that the price is reasonable, the electrical conductivity is high, and the chemical stability is good, but there is a problem of electrical ion migration. Nickel has a low price and relatively good electrical conductivity, but when exposed to high temperature and humidity conditions, it may cause problems such as corrosion or oxidation on the surface.

On the other hand, there are three types of insulating resins used for the production of anisotropic conductive films: thermoplastic type, thermosetting type, and ultraviolet curing type. However, generally used thermosetting type, epoxy resin and acrylic resin are widely used as the thermosetting resin. Epoxy type thermosetting resins have the advantage of showing high adhesion to various types of substrates and relatively superior properties in reliability against high temperature, high temperature, high humidity or cold and thermal shocks, but they exhibit sufficient adhesion at relatively low adhesion temperatures and short adhesion times. The disadvantage is that it is difficult. On the contrary, acrylic type thermosetting resins can express relatively high adhesion even at low adhesion temperature and short adhesion time. However, there is a case that sufficient adhesive strength does not come out depending on the type of substrate, and it is not limited to use. It is known that there is a problem in reliability.

For this reason, Korean Patent Application No. 2001-0011646 proposes a method of mixing and using an adhesive having a radical polymerization-based thermosetting mechanism and an adhesive having an epoxy-based thermosetting mechanism. Simple mixing does not form a covalent bond between the two may cause a problem of deterioration of reliability.

Therefore, the present invention is to solve the problems of the prior art as described above, when manufacturing a semiconductor circuit directly on the film or glass substrate by the COF or COG method in the manufacture of LCD, it is possible to form an anisotropic conductive film functioning as an adhesive It is an object of the present invention to provide a resin composition having a wide range of applicable substrates and adhesion temperature ranges and excellent reliability such as moisture resistance and heat resistance.

In order to achieve the above object, in the present invention, a phosphorus compound having a specific structure is added as an adhesive force improving component to an existing anisotropic conductive film composition having an epoxy resin as a base resin, and an acrylate as a reliability improving component under high temperature and high humidity conditions. It is characterized by adding an epoxy resin and an acrylic rubber.

That is, the present invention provides a composition for an anisotropic conductive film comprising the following components:

(A) an epoxy resin;

(B) acrylated epoxy resins;

(C) a radically polymerizable compound;

(D) acrylic rubber;

(E) radical initiators;

(F) epoxy curing agents;

(G) amine group-containing phosphorus compounds; And

(H) conductive particles.

Hereinafter, the composition of the present invention will be described in more detail for each component.

As an epoxy resin of the component (A) of this invention, it is preferable to use the polyhydric epoxy resin which has two or more glycidyl groups in 1 molecule, More preferably, a phenol novolak-type epoxy resin and a bisphenol-A epoxy resin Or bisphenol F type epoxy resin is used.

In preparing the composition of the present invention, the component (A) is used in an amount of 5 to 45 parts by weight. If the content of the component (A) is insufficient, the curability is insufficient, the reliability is lowered, and if the content is excessive, the storage stability is poor, there may be a problem in use.

The acrylated epoxy resin of component (B) of the present invention is a form in which some epoxy groups of the epoxy resin are substituted with an acryl group, and such resins are epoxy such as bisphenol A or F type, phenol novolac type, cresol novolac type, and the like. It is prepared by stoichiometrically reacting the photopolymerizable acrylate monomer with respect to the epoxy equivalent of the resin, and commercially available products can be purchased and used in the present invention. Representative examples of the photopolymerizable acrylate monomer substituted in the epoxy resin include (meth) acrylate, hydroxyl ethyl (meth) acrylate, hydroxyl propyl (meth) acrylate, propylene glycol (meth) acrylate, trimethylol Propane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, and the like.

In the present invention, the acryl group of the component (B) is covalently bonded to the epoxy group of the component (A) to increase the degree of curing of the conductive film formed from the composition of the present invention, thereby contributing to the improvement of moisture resistance.

In preparing the composition of the present invention, the component (B) is used in an amount of 5 to 40 parts by weight. When the content of component (B) is insufficient, there is no effect of improving moisture resistance, while when the content is excessive, film formation is rather difficult, which may cause a problem in workability.

The radically polymerizable compound of the component (C) of the present invention is a compound having a functional group that can be cured by a radical, and preferably a compound containing an acrylic group. Examples of such compounds include acryl amide, hydroxy ethyl methacrylate, butyl acrylate, ethylene oxide diacrylate, and the like.

In preparing the composition of the present invention, the component (C) is used in an amount of 5 to 50 parts by weight. If the content of component (C) is insufficient, there is a problem in that the hardenability is lowered and the adhesion and reliability are lowered. If the content is excessive, the hardening rate is excessively increased during ACF bonding, thereby decreasing the adhesion.

The acrylic rubber of the component (D) of the present invention is not particularly limited as long as the object of the present invention is not impaired. However, in the case of acrylic rubber polymerized using methacrylic acid as one of the comonomers, the addition amount of methacrylic acid should be in the range of 2 to 12 mol%, and beyond this range, it is not preferable in terms of adhesion and compatibility. . In addition, when acrylonitrile is used as a main monomer, the content of acrylonitrile is not specifically limited, It is preferable that it is 20 mol% or more from a compatible viewpoint with the other resin which comprises the composition of this invention.

The component (D) has an effect of improving the moisture resistance of the conductive film formed from the composition of the present invention due to its moisture resistance.

In preparing the composition of the present invention, the component (D) is used in an amount of 20 to 70 parts by weight. If the amount is less than 20 parts by weight, sufficient moisture resistance improvement effect cannot be obtained. However, if the content is excessive, the surface tack is excessive, resulting in deterioration of workability and adhesion.

The radical initiator of the component (E) of the present invention is not particularly limited as long as it is a compound that generates radicals by light or heating, and peroxides, azo compounds and the like can be used. However, in terms of high reactivity and storage stability, the half-life is 10 hours. It is preferable to use an organic peroxide having a temperature of 40 ° C. or higher and a temperature of half life of 1 minute of 180 ° C. or lower. Specific examples of the organic peroxide useful in the present invention include diacyl peroxide, peroxydicarbonate, peroxyester, peroxyketal, dialkylperoxide, hydroperoxide and the like.

In the present invention, the component (E) reacts with the acrylic groups of the components (B) and (C) to serve to increase the degree of curing of the film formed from the composition of the present invention.

In preparing the composition of the present invention, the component (E) is used in an amount of 0.5 to 20 parts by weight. If the content of the component (E) is insufficient, the curing reaction does not proceed smoothly during film formation, the degree of curing of the film is lowered, causing a poor reliability, if the content is excessive there is a problem that the storage stability is lowered.

The epoxy curing agent of the component (F) of the present invention is a component that promotes the curing reaction of the epoxy groups of the component (A) and the component (B). In the present invention, a latent curing agent is used, which is stable at room temperature and has at least one activation. The compound having hydrogen in the molecule may be used. Preferably, any one of imidazole-based, polyisocyanate-based, amine-based, amide-based, or acid-anhydride-based curing agents is used alone, or two or more thereof are used in combination.

In preparing the composition of the present invention, the component (F) is used in an amount of 0.5 to 20 parts by weight. If the content of the component (F) is insufficient, the curing reaction does not occur, the film formation itself is impossible, if the content is excessive there is a problem that the storage stability is lowered.

As the phosphorus compound of component (G) of the present invention, a phosphorus compound containing an amine group is used as shown in the following general formula (1):

(Wherein R ₁ , R ₂ , R ₃ and R ₄ are each independently a hydrogen atom or an alkyl group or aryl group having 1 to 10 carbon atoms, and R ₅ is an alkylene group or benzene ring having 1 to 10 carbon atoms).

Preferred examples of the amine group-containing phosphorus compound include phosphoryldimethylethanolamine, 2-dimethylaminophenoldiphenyl phosphate, 2-diethylaminoethanoldimethyl phosphate, 2-ethylpropylaminophenoldihydrogen phosphate, and 2-dibutylamino Phenol dihydrogen phosphate and the like, and one or more of them can be used.

The said component (G) is an essential component in improving the adhesive force to the base material of the conductive film formed from the composition of this invention.

In preparing the composition of the present invention, the component (G) is used in an amount of 0.1 to 10 parts by weight. While the amount of less than 0.1 part by weight does not provide the effect of improving the adhesive strength desired in the present invention, when the content is excessive, there is a problem of deteriorating reliability by corroding metal such as Cu.

As the conductive particles of the component (H) of the present invention, metal particles are used, or inorganic or organic particles coated with gold or silver, and the particle size thereof is not particularly limited as long as the object of the present invention is not impaired. Preferably, the thing of 3 micrometers-25 micrometers is used according to a use. The metal particles are powders of iron, zinc, manganese, gold, silver or nickel, and any one of them may be used alone, or two or more thereof may be mixed and used. The inorganic or organic particles coated with gold or silver may also be used as long as they are known to be usable for anisotropic conductive films.

In preparing the composition of the present invention, the component (H) is used in an amount of 1 to 30 parts by weight. If the content of component (H) is insufficient, the film formed from the composition of the present invention cannot achieve sufficient electrical conductivity, and if the content is excessive, the insulation resistance is lowered, thereby preventing the function as ACF.

No special apparatus or equipment is required to form an anisotropic conductive film using the composition of the present invention. For example, the composition of the present invention may be dissolved in an organic solvent such as toluene to be liquefied, and then, on the release film, After apply | coating to a thickness, and passing through a drier of about 100 degreeC, toluene is volatilized and the anisotropic conductive film which has a single layer structure can be obtained.

Hereinafter, the present invention will be described in more detail with reference to examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

Example 1

The resin solution prepared by mixing the following components was applied onto a white release film, and then passed through a dryer at 100 ° C. to obtain an anisotropic conductive film having a thickness of 40 μm.

(A) epoxy resin

    Epicoat 828 (Mn: 214; Shell Corporation) ---- 20 parts by weight

(B) 50% of epoxy groups substituted by acrylic acid

    Phenolic novolac acrylated epoxy resin

    EA-6310 (Shin Nakachon Industry Co., Ltd.) ---- 15 parts by weight

(C) radically polymerizable compound

    Ethylene oxide diacrylate ---- 20 parts by weight

(D) acrylic rubber

    AT-4000 (Samwon Co., Ltd.) ---- 50 parts by weight

(E) radical initiator

    Igacure 651 (Switzerland Pharmaceutical Chemicals Corporation) ---- 5 parts by weight

(F) epoxy curing agent

    2-methylimidazole ---- 5 parts by weight

(G) phosphorus compounds

    Phosphoryldimethylethanolamine ---- 1 part by weight

(H) conductive particles

    Nickel powder (average particle size 3 ~ 8㎛) ---- 7 parts by weight

(I) solvent

    Toluene ---- 100 parts by weight

Example 2

The above-mentioned implementation was carried out except that particles having an average particle diameter of 5 µm coated with a 0.09 µm-thick Ag layer on the surface of the particles (compressive modulus of 480 Kgf / mm 2) having polystyrene as the nucleus as the conductive particles of component (H) were used. A resin solution was prepared in the same composition as in Example 1. After apply | coating the said resin solution on the white mold release film, it passed through the dryer of 100 degreeC, and obtained the anisotropic conductive film of 40 micrometers thickness.

Comparative Example 1

A resin solution was prepared in the same composition as in Example 1, except that the phosphorus compound of component (G) was omitted. After apply | coating the said resin solution on the white mold release film, it passed through the dryer of 100 degreeC, and obtained the anisotropic conductive film of 40 micrometers thickness.

Comparative Example 2

A resin solution was prepared in the same composition as in Example 1, except that the acrylated epoxy resin of component (B) was omitted. After apply | coating the said resin solution on the white mold release film, it passed through the dryer of 100 degreeC, and obtained the anisotropic conductive film of 40 micrometers thickness.

Comparative Example 3

A resin solution was prepared in the same composition as in Example 1, except that NBR (DN-003, manufactured by Nippon Zeon) was used instead of the acrylic rubber of component (D). After apply | coating the said resin solution on the white mold release film, it passed through the dryer of 100 degreeC, and obtained the anisotropic conductive film of 40 micrometers thickness.

[Evaluation of Physical Properties of Anisotropic Conductive Film]

In order to evaluate the physical properties of the anisotropic conductive films prepared according to Examples 1 and 2 and Comparative Examples 1 to 3, each film was left at room temperature (25 ° C.) for 1 hour, and then using this, a line width of 50 μm and a pitch of 100 were used. A printed circuit board (PCB) having 250 micrometers and 18 micrometers copper circuits and a copper circuit having a line width of 50 micrometers, a pitch of 100 micrometers and a copper circuit of 18 micrometers in thickness was fabricated at 140 and 180 degrees Celsius. It was bonded by heating and pressing for 15 seconds at a pressure of 3MPa under the temperature conditions.

Adhesion of the completed sample was measured by the 90 ° peel adhesion measurement method, but after measuring a total of five times for each sample, the average value was taken as the initial adhesion. In addition, in order to verify the reliability, after performing a thermal shock test at a high temperature (85 ℃) high humidity (85% relative humidity) conditions for 500 hours, the adhesive force was measured and compared with the initial adhesive force (see Table 1).

Compare Initial adhesive force (gf / cm) Adhesive force after high temperature and humidity test (gf / cm) 140 ℃ 180 ℃ 140 ℃ 180 ℃ Example 1 1257 1355 1425 1443 Example 2 1232 1385 1456 1421 Comparative Example 1 865 1023 1035 1124 Comparative Example 2 1136 1250 968 942 Comparative Example 3 956   1099 656 751

As can be seen in Table 1, in the case of Examples 1 and 2 shows a high adhesive strength of 1200gf / cm or more even at the adhesion temperature of 140 ℃. In other words, it exhibits sufficient adhesion even at relatively low adhesion temperatures. And even after the high temperature and high humidity reliability test in the case of Example 1 and Example 2 maintains a high adhesive strength of 1400 gf / ㎝. On the other hand, in Comparative Example 1, in which the phosphorus compound was not added, the initial adhesive strength at the time of adhesion at 140 ° C. was significantly low, 865 gf / cm. It supports the effect of improving.

On the other hand, in the case of Comparative Example 2 without the addition of the acrylated epoxy resin, the initial adhesive strength at the time of adhesion at 140 ℃ can be said to be relatively high, after the high temperature and high humidity test it was observed that the adhesive strength is greatly reduced. This is considered to be because, when the acrylated epoxy resin is not added, covalent bonds between the epoxy group of the resin component and the acrylic group are not formed and the moisture resistance at high temperature and high humidity conditions is inferior.

And, in the case of Comparative Example 3 used a general NBR instead of acrylic rubber, in this case also it can be seen that the adhesion after the high temperature and high humidity test is very degraded. It is believed that this is because the moisture resistance of NBR is inferior to that of the acrylic rubber used in the present invention.

On the other hand, the conductivity of each film was evaluated by measuring the connection resistance value between adjacent circuits of the said TCP with a multimeter (refer: Table 2).

Compare Initial connection resistance (mΩ) Connection resistance after high temperature and humidity test (m 습) 140 ℃ 180 ℃ 140 ℃ 180 ℃ Example 1 255 240 325 423 Example 2 244 289 289 326 Comparative Example 1 321 252 324 396 Comparative Example 2 266 259 857 689 Comparative Example 3 354 391 789 852

As can be seen in Table 2 above, the initial connection resistance of the Examples and Comparative Examples is less than 1 kW, but there is no problem in use, but the connection resistance after the high temperature and high humidity test is not more than 1 kW. In case of 3, the connection resistance is significantly increased more than twice the initial value. This is judged to be due to the fact that the overall curing degree of the film was decreased due to the lack of acrylated epoxy resin in Comparative Example 2 and the moisture resistance was decreased. In Comparative Example 3, the moisture resistance of NBR was used in the present invention. This is because it is inferior to rubber.

As described in detail above, the anisotropic conductive film formed from the composition of the present invention exhibits high adhesion in a wide temperature range and maintains excellent reliability even under high temperature and high humidity conditions. When used for interconnection, constant physical properties can be exhibited without changing the initial adhesion to provide a highly reliable product.

Claims (4)

Composition for anisotropic conductive film containing the following components: (A) an epoxy resin; 5-45 parts by weight; (B) acrylated epoxy resins; 5-40 parts by weight; (C) a radically polymerizable compound; 5-50 parts by weight; (D) acrylic rubber; 20 to 70 parts by weight; (E) radical initiators; 0.5-20 parts by weight; (F) epoxy curing agents; 0.5-20 parts by weight; (G) Phosphorus compound containing amine group which has a structure of following General formula (1): 0.1-10 weight part           [Formula 1] (Wherein R ₁ , R ₂ , R ₃ , and R ₄ are each independently a hydrogen atom or an alkyl group or aryl group having 1 to 10 carbon atoms, and R ₅ is an alkylene group or benzene ring having 1 to 10 carbon atoms); And (H) 1-30 weight part of electroconductive particles. delete The epoxy group of claim 1, wherein some of the epoxy groups of the epoxy resin of bisphenol A type, bisphenol F type, phenol novolac type or cresol novolac type (meth) acrylate, hydroxyl ethyl (meth) acrylic 1 acryl selected from the group consisting of latex, hydroxyl propyl (meth) acrylate, propylene glycol (meth) acrylate, trimethylolpropane tri (meth) acrylate and ethoxylated trimethylolpropane tri (meth) acrylate A composition characterized in that the form is substituted with a rate monomer. The amine group-containing phosphorus compound according to claim 1, wherein the amine group-containing phosphorus compound is phosphoryldimethylethanolamine, 2-dimethylaminophenoldiphenyl phosphate, 2-diethylaminoethanoldimethyl phosphate, 2-ethylpropylaminophenoldihydrogen phosphate and 2- At least one member selected from the group consisting of dibutylaminophenol dihydrogen phosphate.