JP2003045235A - Anisotropy conductive paste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anisotropy conductive paste that is superior in storage stability and dispenser painting work performance and does not have occurrence of resin fall-out, gas and spread at the thermo-compression bonding, and the hardened substance has high reliability of adhesion and connection at high temperature and high humidity, and has a good repair performance. SOLUTION: The anisotropy paste contains (I) 30-80 mass % of epoxy resin, (II) 10-50 mass % of amine system hardening agent, (III) 5-25 mass % of a high softening point particulate, (IV) 97-99.9 volume % of resin composite containing 5-25 mass % of poly-silicone, and (V) 0.1-3 volume % of conductive particles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display such as a liquid crystal display, an electroluminescence display, a plasma display, a charge coupled device (CCD), and a CMOS (Complementary Metal Oxide Semiconductor).
The present invention relates to an anisotropic conductive paste used for connecting fine wiring of an electric circuit used for a semiconductor device, and a method for connecting electric circuit wiring using the anisotropic conductive paste.

[0002]

2. Description of the Related Art In recent years, liquid crystal displays and the like used in television receivers, personal computers, mobile phones, etc. have been made finer and smaller, and accordingly, the wiring of the integrated circuit of the driver has become narrower. It is pitching. In addition, in order to maintain high productivity, the temperature is 200
TCP mounted with an integrated circuit under severe thermocompression bonding conditions such as ℃, pressure of 2 MPa and time of 20 to 30 seconds.
The wiring of (Tape Carrier Package) and the wiring of the liquid crystal display board are connected.

Conventionally, in order to connect such wirings, anisotropy is obtained by dispersing fine conductive particles in a resin as disclosed in Japanese Patent Laid-Open No. 3-46707. An anisotropic conductive film is used. However, since this anisotropic conductive film is manufactured by forming it into a film using a release film, the manufacturing cost is high and expensive, and it is necessary to install a dedicated automatic peeling machine at the time of use. There is a problem in terms of cost. In addition, sufficient adhesive strength cannot be obtained,
There is also a problem that the connection reliability is lowered under high temperature and high humidity.

Materials for solving these problems are disclosed in Japanese Patent Laid-Open Nos. 62-40183 and 62-76215.
An anisotropic conductive paste or an anisotropic conductive adhesive that is liquid at room temperature as disclosed in Japanese Patent Laid-Open No. 62-176139. However,
The viscosity of these anisotropic conductive pastes or anisotropic conductive adhesives is drastically reduced in the thermocompression bonding process involving a rapid temperature rise. Therefore, there is a problem that the resin comes off due to the generation of the liquid flow or the bleeding contamination occurs. In addition, there is a problem such as poor conduction in the pressure bonding direction due to the occurrence of partial aggregation of the conductive particles. These phenomena are caused by bubbles present in the anisotropic conductive paste and the like. Further, after the anisotropic conductive paste or the like is hardened, there is a problem that the connection reliability at high temperature and high humidity cannot be maintained due to the bubbles remaining in the hardened material. Furthermore, although the cured product has sufficient strength, it has a problem that it does not have repairability.

Therefore, in particular, even under severe thermocompression bonding conditions such as a temperature of 200 ° C., a pressure of 2 MPa, and a time of 20 to 30 seconds, no bubbles remain in the cured product, which results in high adhesion reliability, connection reliability and repair. A material having properties is desired.

[0006]

The object of the present invention is excellent in storage stability and workability of dispenser application, and there is no resin dropout, bubble and exudation during thermocompression bonding, and the cured product thereof has high temperature and high humidity. An object of the present invention is to provide an anisotropic conductive paste having high adhesive reliability and connection reliability and repairability.

[0007]

According to the present invention, (I) epoxy resin is 30 to 80% by mass, (II) amine curing agent is 10 to 50% by mass, and (III) high softening point fine particles are 5 to 2%.
5% by mass, 97 to 99.9% by volume of a resin composition containing 5 to 25% by mass of (IV) polysilicone, and (V) 0.1 to 3% by volume of conductive particles. It is an anisotropic conductive paste.

The present invention also provides (I) epoxy resin 30
˜79.9 mass%, (II) amine curing agent 10-5
0% by mass, (III) 5 to 25% by mass of high softening point fine particles, (IV) 5 to 25% by mass of polysilicone, (V)
I) resin composition 97 to 99.9% by volume containing 0.1 to 5% by mass of coupling agent, and (V) conductive particles 0.1 to 3
The anisotropic conductive paste is characterized by containing a volume%.

Further preferably, the epoxy resin (I)
Has an average of 1 to 6 epoxy groups in one molecule and a molecular weight of 100 to 7,000.

Preferably, the amine curing agent (I
As I), an imidazole-based curing agent is used, and the imidazole-based curing agent is microencapsulated.

Preferably, the high softening point fine particles (I
II) has a softening point temperature of 60 to 150 ° C. and 1
Use the particles having a secondary particle size of 0.01 to 2 μm,
High softening point fine particles obtained by copolymerizing methyl (meth) acrylate and a copolymerizable monomer other than the methyl (meth) acrylate, the fine particles having 30 to 70% by mass of the methyl (meth) acrylate. To use.

Also preferably, the above-mentioned polysilicone (I
V) uses a silicone-modified elastomer, and the softening point temperature of the silicone-modified elastomer is −
The temperature is 80 to 0 ° C., the elastomer is present as particles, and the primary particle diameter thereof is 0.05 to 5 μm. More preferably, the silicone-modified elastomer is grafted on an epoxy resin.

Preferably, the surface component of the conductive particles (V) is gold or nickel.

Preferably, the anisotropic conductive paste has a viscosity at 25 ° C. of 30 to 400 Pa · s.

Further preferably, the anisotropic conductive paste is used for any one of a circuit material, a liquid crystal display, an electroluminescence display, a plasma display, a charge coupled device and a semiconductor device.

According to the present invention, the storage stability and dispenser coating workability are excellent, there is no resin omission, air bubbles and exudation during thermocompression bonding, and the cured product thereof has reliable adhesion even at high temperature and high humidity. Also, an anisotropic conductive paste having high connection reliability and repairability can be obtained. In addition, by using such an anisotropic conductive paste, a short circuit of wiring does not occur, and the insulation between adjacent wirings is maintained.

Further, the present invention is characterized in that the anisotropic conductive paste connects the electric circuit wiring formed on one substrate and the electric circuit wiring formed on the other substrate. This is a circuit wiring connection method.

According to the present invention, since the anisotropic conductive paste which can obtain high adhesion reliability and connection reliability even at high temperature and high humidity is used, the wirings can be reliably connected.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The anisotropic conductive paste of the present invention is
(I) Epoxy resin 30 to 80% by mass, (II) Amine curing agent 10 to 50% by mass, (III) High softening point fine particles 5 to 25% by mass, (IV) Polysilicone 5 to 5% by mass.
Resin composition (hereinafter referred to as resin composition 1) containing 25% by mass of 97 to 99.9% by volume, and (V) conductive particles 0.1.
˜3% by volume.

Further, the epoxy resin (I) is added in an amount of 30 to 79.
9 mass%, (II) amine curing agent 10 to 50 mass%, (III) high softening point fine particles 5 to 25 mass%, (I
V) 97 to 99.9% by volume of a resin composition (hereinafter, referred to as resin composition 2) containing 5 to 25% by weight of polysilicone and 0.1 to 5% by weight of (VI) coupling agent, and (V) It may be prepared by including 0.1 to 3% by volume of conductive particles. In the following description, the resin composition 1 and the resin composition 2
Are collectively referred to as a resin composition.

With the above-mentioned constitution, an anisotropic conductive paste having excellent storage stability and dispenser coating workability and free from resin loss during hot pressing, bubbles and exudation can be obtained, The cured product also has high adhesion reliability and connection reliability even at high temperature and high humidity, and also has repairability. The anisotropic conductive paste of the present invention is
It has the property of being electrically conductive in the direction in which it is cured by applying pressure and insulating in the other direction. The components (I) to (VI) will be described in detail below.

The amount of the epoxy resin (I) used in the anisotropic conductive paste of the present invention is preferably 30 to 80% by mass in the resin composition. Further, when the (VI) coupling agent described later is included in the resin composition, the content is preferably 30 to 79.9% by mass.

The amount of the epoxy resin (I) used is 30% by mass.
By the above, the adhesive reliability and connection reliability can be secured in the cured product of the anisotropic conductive paste of the present invention, and the cured product of the anisotropic conductive paste of the present invention can be repaired by setting the content to 80% by mass or less. You can secure the sex. Here, the term "repairability" means that when a problem occurs after the electrodes and the like are bonded together with an anisotropic conductive paste, the paste may be peeled and then re-bonded, but at that time, the paste is peeled off. The paste does not remain on materials such as glass substrates, and it is the ability to withstand reuse.

Epoxy resin (I) used in the present invention
As the epoxy resin, a known one may be used, but preferably 1 to 6 epoxy groups are averaged in one molecule of the epoxy resin (I).
It is preferable to use those having an average number of 1.2, more preferably 1.2 to 6, and even more preferably 1.7 to 6.
When the epoxy resin (I) has an average of 1 to 6 epoxy groups in one molecule, the anisotropic conductive paste of the present invention can have adhesive reliability and connection reliability at high temperature and high humidity.

The molecular weight of the epoxy resin (I) is as follows.
Gel permeation chromatography (hereinafter GP
The polystyrene-equivalent number average molecular weight is 10)
It is in the range of 0 to 7,000. Preferably 150-300
It is 0, and more preferably in the range of 350 to 2000. The polystyrene-equivalent number average molecular weight by GPC is 10
When it is from 0 to 7,000, the workability of the anisotropic conductive paste of the present invention in dispenser application can be maintained.

The epoxy resin (I) may be liquid or solid at room temperature. For example, one selected from a monofunctional epoxy resin and a polyfunctional epoxy resin may be used alone, or two or more kinds may be used in combination.

As the monofunctional epoxy resin, an aliphatic monoglycidyl ether compound, an aromatic monoglycidyl ether compound, an aliphatic monoglycidyl ester compound,
Examples thereof include aromatic monoglycidyl ester compounds, alicyclic monoglycidyl ester compounds, nitrogen element-containing monoglycidyl ether compounds, monoglycidylpropyl polysiloxane compounds, and monoglycidyl alkanes.

Examples of the aliphatic monoglycidyl ether compounds include those obtained by the reaction of polyalkylene monoalkyl ethers with epichlorohydrin, those obtained by the reaction of aliphatic alcohols with epichlorohydrin, and the like. As the polyalkylene monoalkyl ethers, having an alkyl group or an alkenyl group having 1 to 6 carbon atoms, ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether, triethylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether, Examples thereof include propylene glycol monoalkyl ether, dipropylene glycol monoalkyl ether, tripropylene glycol monoalkyl ether, polypropylene glycol monoalkyl ether and the like. Examples of the aliphatic alcohols include n-butanol, isobutanol, n-octanol, 2-ethylhexyl alcohol, dimethylolpropane monoalkyl ether, methylolpropane dialkyl ether, glycerin dialkyl ether, dimethylolpropane monoalkyl ester, and methylolpropane dialkyl. Examples thereof include esters and glycerin dialkyl esters.

Examples of the aromatic monoglycidyl ether compounds include those obtained by reacting aromatic alcohols or alcohols obtained by modifying them with alkylene glycols such as ethylene glycol and propylene glycol, and epichlorohydrin. Examples of the aromatic alcohols include phenol, benzyl alcohol, xylenol, and naphthol.

As the above-mentioned aliphatic monoglycidyl ester compound, a compound obtained by reacting an aliphatic dicarboxylic acid monoalkyl ester with epichlorohydrin,
Examples of the aromatic monoglycidyl ester compound include those obtained by the reaction of aromatic dicarboxylic acid monoalkyl ester and epichlorohydrin.

As the polyfunctional epoxy resin, an aliphatic polyvalent glycidyl ether compound, an aromatic polyvalent glycidyl ether compound, an aliphatic polyvalent glycidyl ester compound,
Aromatic polyvalent glycidyl ester compound, aliphatic polyvalent glycidyl ether ester compound, aromatic polyvalent glycidyl ether ester compound, alicyclic polyvalent glycidyl ether compound, aliphatic polyvalent glycidyl amine compound, aromatic polyvalent glycidyl amine compound , Hydantoin type polyvalent glycidyl compound, novolak type polyvalent glycidyl ether compound, epoxidized diene polymer, 3,4-epoxy-6
-Methylcyclohexylmethyl-3,4-epoxy-6
-Methylcyclohexane carbonate, bis (2,3-
Epoxycyclopentyl) ether and the like.

Examples of the aliphatic polyhydric glycidyl ether compound include those obtained by the reaction of polyalkylene glycols with epichlorohydrin, those obtained by the reaction of polyhydric alcohols with epichlorohydrin, and the like. Examples of the polyalkylene glycols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and polypropylene glycol. Examples of the polyhydric alcohols include dimethylolpropane, trimethylolpropane, spiroglycol, and glycerin.

Examples of the aromatic polyhydric glycidyl ether compounds include those obtained by reacting aromatic diols or diols obtained by modifying them with alkylene glycols such as ethylene glycol and propylene glycol, and epichlorohydrin. Examples of the aromatic diols include bisphenol A, bisphenol S, bisphenol F and bisphenol AD.

Examples of the aliphatic polyhydric glycidyl ester compounds include those obtained by reacting an aliphatic dicarboxylic acid such as adipic acid or itaconic acid with epichlorohydrin.

Examples of the aromatic polyhydric glycidyl ester compounds include those obtained by reacting an aromatic dicarboxylic acid such as isophthalic acid, terephthalic acid and pyromellitic acid with epichlorohydrin.

Examples of the aliphatic polyvalent glycidyl ether ester compound and the aromatic polyvalent glycidyl ether ester compound include those obtained by the reaction of a hydroxydicarboxylic acid compound and epichlorohydrin.

Examples of the aliphatic polyhydric glycidyl amine compound include those obtained by reacting an aliphatic diamine such as polyethylene diamine with epichlorohydrin.

Examples of the aromatic polyvalent glycidylamine compounds include those obtained by the reaction of aromatic diamines such as diaminodiphenylmethane, aniline and metaxylylenediamine with epichlorohydrin.

Examples of the hydantoin-type polyvalent glycidyl compound include those obtained by reacting hydantoin or a derivative thereof with epichlorohydrin.

The novolak-type polyhydric glycidyl ether compound is obtained by the reaction of a novolak resin derived from phenol or cresol and formaldehyde with epichlorohydrin, polyphenols such as polyalkenylphenol and its copolymers, and epichlorohydrin. Those obtained by the reaction of.

Examples of the epoxidized diene polymer include epoxidized polybutadiene and epoxidized polyisoprene.

The amount of the amine-based curing agent (II) used in the anisotropic conductive paste of the present invention is preferably 10 to 50% by mass in the resin composition. By setting the amount of the amine-based curing agent (II) to 10% by mass or more, the anisotropic conductive paste of the present invention is cured in a short time during thermocompression bonding, so that fine wiring can be connected in a very short time. can do. Further, when the content is 50% by mass or less, the amount of unreacted curing agent can be suppressed, and high adhesion reliability and connection reliability of the cured product of the epoxy resin (I) can be obtained.

As the amine type curing agent (II), a latent epoxy curing agent may be used, and it is particularly preferable to use a latent epoxy curing agent which exhibits thermosetting activity by heating at 40 ° C. or higher. As the latent epoxy curing agent which exhibits thermosetting activity by heating at 40 ° C. or higher, one selected from already known ones may be used alone, or a mixture of two or more kinds may be used.

Examples of the latent epoxy curing agent which exhibits thermosetting activity when heated at 40 ° C. or higher include dicyandiamide, dicyandiamide derivatives, dividazid compounds such as adipic acid dihydrazide and isophthalic acid dihydrazide. Further, a derivative of an imidazole compound and a modified product thereof, that is, an imidazole-based curing agent may be used. Specifically, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-
Examples thereof include imidazole derivatives such as n-pentadecylimidazole, complexes with aromatic acid anhydrides, adducts of imidazole compounds and epoxy resins, modified derivatives thereof, and modified microcapsules.

Examples of the modified microcapsules, that is, microcapsulated imidazole-based curing agents include imidazole-based curing agents such as 2-ethyl-4-methylimidazole, 2-methylimidazole, and 2-n-pentadecylimidazole. As a core material, a micro-encapsulated product in which a fine shell is contained is mentioned.

The high softening point fine particles (III) are melted in the anisotropic conductive paste of the present invention at a softening point temperature or higher to increase the viscosity of the paste and suppress the flow of the paste. Further, repairability is also imparted to the anisotropic conductive paste of the present invention.

The amount of the high softening point fine particles (III) used in the anisotropic conductive paste of the present invention is 5 to 25% by mass, preferably 13 to 19% by mass in the resin composition.
Is the range. The amount of high softening point fine particles (III) used is 5
When the content is at least mass%, it is possible to suppress the occurrence of resin loss and exudation during thermocompression bonding. Further, when the content is 25% by mass or less, the viscosity of the anisotropic conductive paste of the present invention does not increase too much, and workability such as dispenser application becomes high.

High softening point fine particles (II
As I), a known one may be used as long as it has a softening point temperature of 60 to 150 ° C. and a primary particle diameter of 0.01 to 2 μm. Here, the primary particles are particles that cannot be mechanically separated any more.

When the softening point temperature is 60 ° C. or higher, the storage stability of the anisotropic conductive paste of the present invention at room temperature becomes high. Moreover, when it is 150 ° C. or lower, 150 to 200 ° C.
In the thermocompression bonding step, the flow of the anisotropic conductive paste can be suppressed and repairability can be imparted. The primary particle diameter of the high softening point fine particles (III) is preferably 0.01 to 2 μm in terms of workability such as dispenser application and connection reliability.

Preferably, emulsion fine particles obtained by copolymerizing 30 to 70% by mass of a monomer methyl (meth) acrylate and another copolymerizable monomer,
More preferably, a finely crosslinked structure is formed on the emulsion fine particles by using a polyfunctional monomer. By using these in the anisotropic conductive paste of the present invention, the storage stability of the anisotropic conductive paste of the present invention at room temperature becomes higher, and the occurrence of resin loss and exudation during thermocompression bonding is further suppressed. You can

Examples of the monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate,
2-ethylhexyl (meth) acrylate, amyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, butoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, glycidyl Acrylic esters such as (meth) acrylate, acrylamides, (meth) acrylic acid,
Acid monomers such as itaconic acid and maleic acid, styrene,
Examples thereof include aromatic vinyl compounds such as styrene derivatives.

As the polyfunctional monomer for forming a finely crosslinked structure in the emulsion fine particles, divinylbenzene, diacrylates, 1,3-butadiene,
Examples thereof include conjugated dienes such as 1,3-pentadiene, isoprene, 1,3-hexadiene, and chloroprene.

As a method for slightly cross-linking the surface of the emulsion fine particles, there may be mentioned a method for cross-linking the ionomer by metal-cross-linking the epoxy group, the carboxyl group and the amino group of the surface layer of the emulsion fine particles. By forming a fine crosslinked structure in the emulsion fine particles,
It will not dissolve easily in the epoxy resin (I), solvent, etc. at room temperature, and the storage stability of the anisotropic conductive paste of the present invention can be improved.

The amount of polysilicone (IV) used in the anisotropic conductive paste of the present invention is
It is 5 to 25% by mass, preferably 7 to 15% by mass. By using the polysilicone (IV) in an amount of 5% by mass or more, the anisotropic conductive paste of the present invention can be provided with defoaming properties. Further, when the content is 25% by mass or less, the adhesiveness of the anisotropic conductive paste and the deterioration of the gas barrier property can be suppressed, and the dispenser coating workability can be maintained.

Polysilicone (IV) is preferably a silicone-modified elastomer. By making the silicone into an elastomer, it is possible to reduce physical shock from the outside, thermal strain during a thermal cycle test, and the like when the anisotropic conductive paste is cured. Further, by modifying the elastomer with silicone, it is possible to further alleviate physical impact from the outside, thermal strain during a thermal cycle test, and the like. Here, the silicone modification is to graft-bond a silicone having a functional group to an elastomer.

Further, as the polysilicone (IV),
It is more preferable to use a silicone-modified elastomer grafted to an epoxy resin other than the epoxy resin (I) which is a component of the anisotropic conductive paste of the present invention. Generally, the compatibility between epoxy resin and silicone is low, and phase separation easily occurs. Therefore, by using the silicone-modified elastomer grafted to the epoxy resin, it becomes possible to uniformly disperse the poly-silicone (IV) in the anisotropic conductive paste.

The elastomer preferably has a softening point temperature of -80 to 0 ° C. Softening point temperature is -80 ~
By setting the temperature to 0 ° C., the effect of relieving physical shock from the outside and thermal strain at the time of a thermal cycle test is improved,
High adhesive strength can be secured.

The primary particle size of the elastomer is
Rubber-like polymer fine particles having a particle size of 0.05 to 5 μm or less are preferable, and a range of 0.1 to 3.5 μm is more preferable. By setting the primary particle diameter to 0.05 μm or more,
Aggregation does not occur, the viscosity of the anisotropic conductive paste is stable, and workability such as dispenser application can be secured. Also,
By setting the primary particle diameter to 5 μm or less, workability such as dispenser application can be ensured, and high adhesive strength can be ensured.

As a method for forming the elastomer, a method using fine particles of silicon rubber, JP-A-60-7295 is used.
The method disclosed in Japanese Patent Laid-Open No. 7-17052
No. 3, the method disclosed in Japanese Patent Publication No. 3, a double bond is introduced into an epoxy resin, a hydrogen-containing silicon capable of reacting with the double bond is reacted to produce a graft body, and a silicone rubber is produced in the presence of the graft body. A method of polymerizing a monomer, a method of introducing a double bond into an epoxy resin and reacting a polymerizable vinyl group-containing silicone rubber monomer with the epoxy resin to form a graft body, and polymerizing a silicone rubber monomer in the presence of the graft body. Method etc. are mentioned. Preferred are a method of forming a graft body without using silicone rubber fine particles and a method of producing silicon rubber fine particles after producing the graft body, and these methods are easy to control the produced silicon rubber fine particles. Further, the elastomer obtained by these methods has a small increase in viscosity even when dispersed, so that good dispenser coating workability can be obtained.

The coupling agent (VI) is used to improve the adhesive strength between the anisotropic conductive paste and the base material, and the amount used is 0.1 to 5% by mass in the resin composition. is there. High adhesive reliability can be obtained by using 0.1 mass% or more. Further, when the content is 5% by mass or less, deterioration of the curability of the anisotropic conductive paste of the present invention can be prevented, and contamination of peripheral members can be prevented.

As the coupling agent (VI), known coupling agents can be used. Specific examples include a trialkoxysilane compound and a methyldialkoxysilane compound. More specifically,
γ-glycidoxypropylmethyldimethoxysilane, γ
-Glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyl Methyldimethoxysilane, γ-aminopropyltrimethoxysilane, N-aminoethyl-γ-iminopropylmethyldimethoxysilane, N-aminoethyl-γ-iminopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-aminopropyl Trimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropyltriethoxysilane. And the like.

The conductive particles (V) in the anisotropic conductive paste of the present invention are 0.1% of those of the anisotropic conductive paste of the present invention.
~ 3% by volume. By setting the content to be 0.1% by volume or more, electrical conductivity in the direction perpendicular to the pressure-bonded surface can be reliably obtained. Further, by setting the content to 3% by volume or less, it is possible to secure insulation between adjacent wirings in the horizontal direction with respect to the crimping surface even when electrodes having a narrow pitch are connected to each other.

As the conductive particles (V), known particles can be used. Specifically, gold, nickel,
Conductive particles of noble metals such as silver and platinum, conductive particles of noble metal alloys such as silver-copper alloy, gold-copper alloy and nickel alloy,
Examples thereof include conductive particles obtained by forming a film of the above-mentioned noble metal or noble metal alloy on fine particles of an organic polymer such as polystyrene. Preferably, conductive particles of noble metal gold or nickel, conductive particles obtained by forming a noble metal film of gold or nickel on organic polymer fine particles, that is, conductive particles whose surface component is formed of gold or nickel. Is to use. As a commercially available product, Sekisui Fine Chemical's product name "Micropearl A"
U series ”. It is preferable to use those conductive particles having a particle diameter in the range of 2 to 20 μm.

The viscosity of the anisotropic conductive paste of the present invention is 2
30 to 400 Pa · s (EH type viscometer,
2.5 rpm) is preferable. Viscosity 30Pa
-By setting it to be s or more, it is possible to suppress the flow of resin which causes bubbles during curing by thermocompression bonding.
Further, when the pressure is 400 Pa · s or less, the dispenser coating workability can be maintained.

To prepare the anisotropic conductive paste of the present invention,
Other additives such as inorganic fillers and solvents may be used.

The above-mentioned inorganic filler is used for the purpose of adjusting the viscosity and reducing the thermal stress of the cured product, and can be selected from the already known inorganic compounds. Specifically, calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, zirconium silicate, iron oxide, titanium oxide, aluminum oxide (alumina), zinc oxide, silicon dioxide, potassium titanate, kaolin, talc. , Asbestos powder, quartz powder, mica, glass fiber and the like. The particle size of the inorganic filler is
There is no particular limitation as long as it does not affect the conduction characteristics of the anisotropic conductive paste, but it is preferable to use one having a thickness of 2 μm or less. The amount of the inorganic filler used is not particularly limited as long as it does not affect the conduction characteristics of the anisotropic conductive paste, but is preferably 40% by mass or less.

The inorganic filler is partially or wholly
It is preferable that 1 to 50 mass% of at least one of the epoxy resin (I) and the coupling agent (VI) is graft-modified with respect to 100 mass% of the inorganic filler. That is, it is preferable to use an inorganic filler having a grafting ratio of 1 to 50, which is represented by the weight increase ratio obtained by the repeated solvent washing method.

Here, the repeated solvent washing method is a method of obtaining the grafting ratio as follows. First, the inorganic filler partially or wholly graft-modified,
Wet filtration is repeated 5 to 10 times with 10 to 20 times the mass of the following solvent. By this filtration, the epoxy resin (I) not modified by grafting and the coupling agent (VI)
Are washed away. The solvent is a good solvent for the epoxy resin (I) or the coupling agent (VI),
For example, acetone, methyl ethyl ketone, methanol,
Examples thereof include ethanol, toluene and xylene. Next, the inorganic filler remaining after the filtration is dried and its mass is measured. This mass is the dry mass of the graft-modified inorganic filler. From this measured value, the mass increase rate is calculated according to the following calculation formula. The grafting rate may be obtained by a Soxhlet continuous extraction method using the solvent instead of the repeated solvent washing method.

Grafting ratio = [(dry mass of inorganic filler modified by grafting-dry mass of inorganic filler before grafting modification) / dry mass of inorganic filler before grafting modification] × 100

The solvent is used to secure smoothness after application of the dispenser and to improve wettability to a member to which the anisotropic conductive paste is applied, and is compatible with the epoxy resin (I). If there is no particular limitation. The boiling point is preferably less than 200 ° C, more preferably the boiling point is 40 to 150 ° C.
Is a solvent of. When the solvent having the above boiling point is used, the viscosity stability when handling the anisotropic conductive paste is ensured, and the solvent can be easily removed even by predrying for a short time.

Specific examples of the solvent include ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ether solvents such as diethylene glycol dimethyl ether, methyl carbitol, ethyl carbitol and butyl carbitol, ethyl acetate, diethylene glycol diacetate and alkoxy. An acetate solvent such as diethylene glycol monoacetate may be used. The amount used is such that no solvent remains after the anisotropic conductive paste is cured.

The connection method of the electric circuit wiring of the present invention will be described by taking the connection method of the electric circuit wiring in the liquid crystal display as an example.

First, in step a1, the anisotropic conductive paste of the present invention is applied to a predetermined position on a liquid crystal display substrate by a dispenser. Next, in step a2, the liquid crystal display substrate is aligned with the TCP that is the IC mounted circuit substrate. Next, in step a3, the anisotropic conductive paste is cured by a heating press fixing method. By these steps a1 to a3,
An electric conduction circuit between the liquid crystal display substrate and the TCP is formed.

When the anisotropic conductive paste is applied by the dispenser in step a1, the entire dispenser is
It may be preheated at a temperature of 0 ° C to 50 ° C. In addition, the application may be performed by computer control, or may be applied to a required site manually.

When the anisotropic conductive paste is hardened by the heating press fixing method in step a3, the temperature for adjusting the hot plate for hot pressing is 100 to 300 ° C., preferably 120 to 250 ° C., more preferably 120. ~ 20
It shall be in the range of 0 ° C. Further, the clamping pressure at the time of hot pressing is preferably 0.1 to 5 MPa, and a uniform thermal pressure is applied to the joint portion between the electrodes. For example, a rubber mat may be arranged between the electrode and the pressing surface for pressing.

As described above, when the wiring of the liquid crystal display substrate and the wiring of the TCP are connected by using the anisotropic conductive paste of the present invention, the connection is made to have conductivity only in the crimping direction. Therefore, insulation between adjacent wirings is maintained, and wirings can be connected with high connection reliability.

In the above-mentioned connection method of electric circuit wiring, the liquid crystal display is explained, but it can also be applied to the connection of electric circuit wiring in a flat panel display such as an electroluminescence display and a plasma display. Examples of the electroluminescence display include an organic electroluminescence display and an inorganic electroluminescence display. The anisotropic conductive paste of the present invention can also be used for connecting wirings of circuit devices, semiconductor devices such as CCDs and CMOSs.

[0078]

The present invention will be described in detail below with reference to examples.

[Synthesis Example 1] 10 equipped with a synthetic stirrer for high softening point fine particles (A), a nitrogen introducing tube, a thermometer, and a reflux cooling tube
In a 00 ml four-necked flask, 400 g of ion-exchanged water,
1.0 g of sodium alkyldiphenyl ether disulfonate was added, and the temperature was raised to 65 ° C. After adding 0.4 g of potassium persulfate thereto, 1.2 g of t-dodecyl mercaptan emulsified with a homogenizer, 156 g of n-butyl acrylate, 4.0 g of divinylbenzene, sodium alkyldiphenyl ether disulfonate 3.0.
g, and a mixed solution consisting of 200 g of ion-exchanged water were continuously added dropwise for 4 hours. After the reaction was continued for 2 hours after the dropping, 232 g of methyl methacrylate was added all at once, and then the reaction was continued for 1 hour. Next, 8 g of acrylic acid was continuously added over 1 hour, the reaction was continued at 65 ° C. for 2 hours, and then cooled. It was neutralized to pH = 7 with potassium hydroxide to obtain an emulsion solution having a solid content of 40.6% by mass.

1,000 g of this emulsion solution was applied to a spray dryer to obtain about 400 g of high softening point fine particles (A) having a water content of 0.1% or less. The softening point of the obtained high softening point fine particles (A) was 80 ° C. The high softening point fine particles (A) had a particle size of 180 nm as measured by an N-4 Coulter counter.

[Synthesis Example 2] 10 equipped with a stirrer for synthesizing high softening point fine particles (B), a nitrogen introducing tube, a thermometer, and a reflux cooling tube
In a 00 ml four-necked flask, 400 g of ion-exchanged water, sodium alkyldiphenyl ether disulfonate 1.
0 g was added and the temperature was raised to 65 ° C. After adding 0.4 g of potassium persulfate thereto, the mixture was emulsified with a homogenizer.
A mixed solution of 1.2 g of dodecyl mercaptan, 156 g of n-butyl acrylate, 4.0 g of divinylbenzene, 3.0 g of sodium alkyldiphenyl ether disulfonate, and 200 g of ion-exchanged water was continuously added dropwise for 4 hours. After the reaction was continued for 2 hours after the dropping, 142 g of methyl methacrylate and 90 g of n-butyl acrylate were added all at once, and then the reaction was continued for 1 hour. Next, 8 g of acrylic acid was continuously added over 1 hour, the reaction was continued at 65 ° C. for 2 hours, and then cooled. P with potassium hydroxide
It was neutralized to H = 7 to obtain an emulsion solution having a solid content of 40.6% by mass.

1,000 g of this emulsion solution was applied to a spray drier to obtain about 400 g of high softening point fine particles (B) having a water content of 0.1% or less. The high softening point fine particles (B) thus obtained had a softening point of 40 ° C. The high softening point fine particles (B) had a particle diameter of 180 nm as measured by an N-4 Coulter counter.

[Synthesis Example 3] 2000 equipped with a synthetic stirrer for silicon elastomer (A), a gas introduction pipe, a thermometer, and a cooling pipe
Prepare a ml four-necked flask, 600 g of bisphenol F type epoxy resin (Epiclone 830S, manufactured by Dainippon Ink and Chemicals) having two epoxy groups in the molecule, 12 g of methacrylic acid, 1 g of dimethylethanolamine, and 50 g of toluene. And at 5 ° C at 110 ° C while introducing air.
After reacting for a time, a double bond was introduced into the epoxy resin. Next, 5 g of hydroxy acrylate, 10 g of butyl acrylate, and 1 g of azobisisobutyronitrile were added, and the mixture was reacted at 70 ° C. for 3 hours and further at 90 ° C. for 1 hour. Then, toluene removal was performed under reduced pressure at 110 ° C. Next, 70 g of a silicon intermediate having a methoxy group in the molecule and 0.3 g of dibutyltin dilaurate are added,
The reaction was carried out at 150 ° C. for 1 hour, and the reaction was further continued for 1 hour in order to remove the produced methanol. To the obtained graft body, 1 / room temperature curing type 2 liquid type silicone rubber
300 g of the mixture obtained in 1 was added and reacted for 2 hours to obtain a silicone elastomer (A) in which crosslinked silicone rubber fine particles were uniformly dispersed.

This silicone elastomer (A) was rapidly cured at a low temperature in the presence of a photocuring catalyst, and the average primary particle diameter value of the dispersed rubber obtained by observing the fracture surface morphology of the cured product with an electron microscope. , 1.0 μm.

Example 1 Bisphenol A type epoxy resin as the epoxy resin (I), high softening point fine particles (II
High softening point fine particles (A) synthesized in Synthesis Example 1 as I), silicone elastomer (A) synthesized in Synthesis Example 3 as polysilicone (IV), and γ-glycidylpropyltrimethoxysilane as coupling agent (VI). KBM-403 (manufactured by Shin-Etsu Silicone) was pre-kneaded with a Dalton mixer, and then kneaded with three rolls. Next, as an amine-based curing agent (II), an imidazole-modified microencapsulated curing agent, and as conductive particles (V), Micropearl Au-205 (manufactured by Sekisui Chemical Co., Ltd.,
After mixing with a specific gravity of 2.67), vacuum kneading and defoaming were performed with a Dalton mixer. The blending amount (unit: g) of each material is shown in Table 1.
Shown in.

The anisotropic conductive paste (P-1) thus obtained was evaluated by the following test methods. The results are shown in Table 2.

<1. Storage stability test> The viscosity of the anisotropic conductive paste (P-1) at 25 ° C was measured and the value was used as a reference. Put P-1 in a polyethylene container, seal,
It was stored under a constant condition of 10 ° C. 25 days after 30 days
The viscosity was measured and the rate of increase was determined. ○: less than 10% △: 10% or more and less than 50% ×: 50% or more

<2. Applicability> Anisotropic conductive paste (P
-1) was filled in a 10 cc syringe and then defoamed. Apply with a dispenser (Shot Master: made by Musashi Engineering) at a speed of 4 cm per second,
The following criteria were used to judge superiority or inferiority. ◯: No bleeding, no stringing, and good appearance. Δ: No bleeding, no stringing, but poor appearance. X: Exudation, stringing occurred, and coating suitability was extremely poor. Was

<3. 150 ° C. Gelation Time Measurement Test> 1 g of anisotropic conductive paste (P-1) was placed on a hot plate at 150 ° C. and stirred with a spatula. The time from when P-1 was placed on the hot plate until the stringing disappeared was measured and used as the gelation time.

<4. Adhesive strength> Anisotropic conductive paste (P
-1) 1 g was applied onto low-alkali glass with a dispenser (shot master: manufactured by Musashi Engineering). 2MP with a ceramic tool at 230 ℃ for 30 seconds
TAB for test (Tape Automated Bondin)
g) The film was pressure-bonded and laminated. After being stored in a constant temperature bath at 25 ° C. and a humidity of 50% for 24 hours, the peel strength was measured by a tensile test device (manufactured by Intesco).

<5. Presence or absence of resin omission> 1 g of the anisotropic conductive paste (P-1) was applied on a low alkali glass with a dispenser (shot master: manufactured by Musashi Engineering). Using a ceramic tool at 230 ° C., a test TAB film was pressure-bonded for 30 seconds at a pressure of 2 MPa to perform bonding. The joint portion was observed with a microscope and superiority or inferiority was judged according to the following criteria. Good: Appearance was good with no resin bleeding or bleeding. C: Partial resin bleeding was observed between the bumps and appearance was poor. X: Resin bleeding or bleeding occurred overall.

<6. Presence or absence of air bubbles> 1 g of the anisotropic conductive paste (P-1) was applied on low-alkali glass with a dispenser (shot master: manufactured by Musashi Engineering). Using a ceramic tool at 230 ° C., the test TAB film was pressure-bonded for 30 seconds at a pressure of 2 MPa to perform bonding. The joint portion was observed with a microscope and superiority or inferiority was judged according to the following criteria. ◯: There were no bubbles and the appearance was good. Δ: Some bubbles were seen between the bumps. ×: Bubbles were seen overall.

<7. Conductivity> Anisotropic conductive paste (P-
1) 1 g was applied onto a low alkali glass having an ITO (Indium Tin Oxide) electrode with a dispenser (shot master: manufactured by Musashi Engineering). Using a ceramic tool at 230 ° C., the test TAB film was pressure-bonded for 30 seconds at a pressure of 2 MPa to perform bonding. I
The resistance between the TO electrode and the electrode on the test TAB film was measured at 60 ° C and 95% RH (relative humidit
y) Measured after 600 hours.

<8. Confirmation test for the presence of shorts between wires>
1 g of anisotropic conductive paste (P-1) was dispensed (shot master: made by Musashi Engineering Co., Ltd.)
It was applied on a low alkali glass having a TO electrode. 23
The test TAB film was pressure-bonded with a ceramic tool at 0 ° C. for 30 seconds at a pressure of 2 MPa to perform bonding. The resistance value between adjacent ITO electrodes was measured and shown by the following criteria. ○: Insulation is secured ×: Conductivity

<9. Repairability> Anisotropic conductive paste (P
-1) 1 g was applied onto low-alkali glass with a dispenser (shot master: manufactured by Musashi Engineering). 2MP with a ceramic tool at 230 ℃ for 30 seconds
The test TAB film was pressure-bonded and bonded at a pressure of a. After washing with a solvent and peeling the test TAB film, the surface of the low-alkali glass was observed with a microscope, and the superiority or inferiority was judged according to the following criteria. ◯: No resin remained and appearance was good Δ: Resin partially remained and appearance was poor X: Resin remained overall

[Example 2] An anisotropic conductive paste (P-2) was prepared and tested in the same manner as in Example 1 except that the compounding amounts were as shown in Table 1. The test results are shown in Table 2.

Example 3 The silicone elastomer (A) in Example 1 was used as a linear silicone DC3037.
Anisotropic conductive paste (P-3) was prepared and tested in the same manner as in Example 1 except that (Shin-Etsu Silicone) was used and the compounding amount was changed as shown in Table 1. Table 2 shows the test results
Shown in.

[Example 4] In addition to the silicone elastomer (A) in Example 1, a linear silicone DC3037 (manufactured by Shin-Etsu Silicone) was used, and the compounding amount was as shown in Table 1. An anisotropic conductive paste (P-4) was prepared and tested in the same manner as in Example 1. The test results are shown in Table 2.

[Example 5] An anisotropic conductive paste (P-5) was prepared and tested in the same manner as in Example 1 except that the compounding amounts were as shown in Table 1. The test results are shown in Table 2.

Example 6 γ-glycidylpropyltrimethoxysilane KBM-403 (manufactured by Shin-Etsu Silicone Co., Ltd.) was not used as the coupling agent (VI) in Example 1 except that the compounding amount was as shown in Table 1. In the same manner as in Example 1, an anisotropic conductive paste (P-6) was prepared and tested. The test results are shown in Table 2.

[Comparative Example 1] An anisotropic conductive paste (C-1) was prepared and tested in the same manner as in Example 1 except that the compounding amounts were as shown in Table 1. The test results are shown in Table 2.

[Comparative Example 2] An anisotropic conductive paste (C-2) was prepared and tested in the same manner as in Example 1 except that the compounding amounts were as shown in Table 1. The test results are shown in Table 2.

Comparative Example 3 The high softening point fine particles (B) synthesized in Synthesis Example 2 were used in place of the high softening point fine particles (A) in Example 1, and the compounding amounts were as shown in Table 1. The anisotropic conductive paste (C
-3) was prepared and tested. The test results are shown in Table 2.

[Comparative Example 4] An anisotropic conductive paste (C-4) was prepared and tested in the same manner as in Example 1 except that the blending amount was changed as shown in Table 1. The test results are shown in Table 2.

[Comparative Example 5] An anisotropic conductive paste (C-5) was prepared and tested in the same manner as in Example 1 except that the compounding amounts were changed as shown in Table 1. The test results are shown in Table 2.

[Comparative Example 6] An anisotropic conductive paste (C-6) was prepared and tested in the same manner as in Example 1 except that the compounding amount was as shown in Table 1. The test results are shown in Table 2.

[0107]

[Table 1]

[0108]

[Table 2]

From Table 2, it can be seen that the anisotropic conductive pastes of Examples 1 to 6 obtained good evaluations in all tests.

[0110]

According to the present invention, it is possible to provide an anisotropic conductive paste which is excellent in storage stability and workability in dispenser application.

Further, according to the present invention, in order to maintain high productivity, the temperature is 200 ° C., the pressure is 2 MPa, and the time is 20.
It is an anisotropic conductive paste that does not cause resin bleeding, bubbles, or exudation even when used for wiring connection under severe thermocompression bonding conditions of ~ 30 seconds, and its cured product adheres even at high temperature and high humidity. Reliable and connection reliable,
An anisotropic conductive paste having high repairability can be provided.

[Brief description of drawings]

FIG. 1 is a process drawing of a method for connecting electrical circuit wiring according to the present invention.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09J 133/06 C09J 133/06 5G307 151/08 151/08 163/00 163/00 183/04 183/04 201/02 201/02 H05K 1/14 H05K 1/14 A 3/32 3/32 B // (C08L 63/00 C08L 33:12 33:12 83:04 83:04) (72) Inventor Tatsushi Murata 580-32 Nagaura, Sodegaura City, Chiba Prefecture Mitsui Chemicals Co., Ltd. (72) Inventor Makoto Nakahara 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Prefecture 22-22 Ikemachi, Sharp Corporation (72) Inventor Daisuke Ikesugi 22-22, Nagaikemachi, Abeno-ku, Osaka-shi, Osaka Prefecture F-terms within Sharp Corporation (reference) 4J002 BG062 CD011 CD051 CD061 CD101 CD131 CD181 CD203 DA077 DA087 DA117 EU116 FA082 FB 286 FD010 FD117 FD146 GJ01 GQ02 4J036 AC17 AD08 AE05 AF06 AG01 AG04 AG07 AH05 AH07 AH10 AJ01 AJ05 CD04 DC41 FA02 FA11 FB03 FB16 HA07 JA06 4J040 DF032 DL052 DL152 EC031 EC041 EC071 EC121 EK032 HA066 HC12 HC15 HC23 HD32 HD35 HD36 HD37 JA11 JB02 JB10 KA03 KA16 KA42 LA01 LA02 LA06 LA08 LA09 LA11 MA10 NA17 PA24 PA30 5E319 AA03 AC03 AC04 BB16 CC12 CD27 GG20 5E344 AA02 AA22 BB02 CD04 CD06 DD10 EE30 5G307 HA02 HB03 HC01

Claims (14)

[Claims] 1. (I) Epoxy resin 30 to 80% by mass, (II) Amine curing agent 10 to 50% by mass, (III) High softening point fine particles 5 to 25% by mass, (IV) Polysilicone An anisotropic conductive paste comprising 97 to 99.9% by volume of a resin composition containing 5 to 25% by mass and (V) 0.1 to 3% by volume of conductive particles. 2. (I) 30 to 79.9 mass% of epoxy resin, (II) 10 to 50 mass% of amine curing agent, (III) 5 to 25 mass% of high softening point fine particles, (IV) 5 to 25 mass% of polysilicone, 97 to 99.9 vol% of a resin composition containing (VI) 0.1 to 5 mass% of a coupling agent, and (V) 0.1 to 3 vol% of conductive particles. An anisotropic conductive paste comprising: 3. The epoxy resin (I) according to claim 1, wherein the epoxy resin (I) has at least 1 to 6 epoxy groups in one molecule on average, and has a molecular weight of 100 to 7000. Directional conductive paste. 4. The anisotropic conductive paste according to claim 1, wherein the amine curing agent (II) is an imidazole curing agent. 5. The anisotropic conductive paste according to claim 4, wherein the imidazole curing agent is microencapsulated. 6. The high softening point fine particles (III) are 60
It has a softening point temperature of ˜150 ° C. and a primary particle size of 0.1.
It is in the range of 01 to 2 μm.
5. An anisotropic conductive paste according to any one of 5 above. 7. The high softening point fine particles (III) are high softening point fine particles obtained by copolymerizing methyl (meth) acrylate and a copolymerizable monomer other than the methyl (meth) acrylate, The methyl (meth) acrylate is contained in an amount of 30 to 70% by mass.
An anisotropic conductive paste according to any one of 1 to 6. 8. The anisotropic conductive paste according to claim 1, wherein the polysilicone (IV) is a silicone-modified elastomer. 9. The softening point temperature of the silicone-modified elastomer is −80 to 0 ° C., the elastomer is present as particles, and the primary particle diameter thereof is 0.0.
It is 5-5 micrometers, The anisotropic conductive paste of Claim 8 characterized by the above-mentioned. 10. The anisotropic conductive paste according to claim 8 or 9, wherein the silicone-modified elastomer is grafted on an epoxy resin. 11. The surface component of the conductive particles (V) is
It is gold or nickel, It is characterized by the above-mentioned.
0. The anisotropic conductive paste according to any one of 0. 12. The viscosity at 25 ° C. is 30 to 400.
It is Pa * s, The anisotropic conductive paste in any one of Claims 1-11 characterized by the above-mentioned. 13. The anisotropic conductive paste according to claim 1, which is used in any one of a circuit material, a liquid crystal display, an electroluminescent display, a plasma display, a charge-coupled device and a semiconductor device. An anisotropic conductive paste characterized by being obtained. 14. The anisotropic conductive paste according to claim 1 connects electrical circuit wiring formed on one substrate and electrical circuit wiring formed on the other substrate. A method for connecting electrical circuit wiring, comprising: